#endif

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>
#include "sqlite3.h"
typedef sqlite3_int64 i64;
typedef sqlite3_uint64 u64;
typedef unsigned char u8;
#if SQLITE_USER_AUTHENTICATION
# include "sqlite3userauth.h"
#endif
#include <ctype.h>
#include <stdarg.h>

#if !defined(_WIN32) && !defined(WIN32)
# include <signal.h>
# if !defined(__RTP__) && !defined(_WRS_KERNEL)
#  include <pwd.h>
# endif
#endif
#if (!defined(_WIN32) && !defined(WIN32)) || defined(__MINGW_H)
# include <unistd.h>
# include <dirent.h>
# if defined(__MINGW_H)
#  define DIRENT dirent
#  ifndef S_ISLNK
#   define S_ISLNK(mode) (0)
#  endif
# endif
#endif
#include <sys/types.h>
#include <sys/stat.h>

#if HAVE_READLINE
# include <readline/readline.h>
# include <readline/history.h>
#endif

#if HAVE_EDITLINE

      lwr = mid+1;
    }else{
      upr = mid-1;
    }
  }
  return 0;
}

/*
** Construct a fake object name and column list to describe the structure
** of the view, virtual table, or table valued function zSchema.zName.
*/
static char *shellFakeSchema(
  sqlite3 *db,            /* The database connection containing the vtab */
  const char *zSchema,    /* Schema of the database holding the vtab */
  const char *zName       /* The name of the virtual table */
){
  sqlite3_stmt *pStmt = 0;
  char *zSql;
  ShellText s;
  char cQuote;
  char *zDiv = "(";
  int nRow = 0;

  zSql = sqlite3_mprintf("PRAGMA \"%w\".table_info=%Q;",
                         zSchema ? zSchema : "main", zName);
  sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
  sqlite3_free(zSql);
  initText(&s);
  if( zSchema ){
    cQuote = quoteChar(zSchema);
    if( cQuote && sqlite3_stricmp(zSchema,"temp")==0 ) cQuote = 0;
    appendText(&s, zSchema, cQuote);
    appendText(&s, ".", 0);
  }
  cQuote = quoteChar(zName);
  appendText(&s, zName, cQuote);
  while( sqlite3_step(pStmt)==SQLITE_ROW ){
    const char *zCol = (const char*)sqlite3_column_text(pStmt, 1);
    nRow++;
    appendText(&s, zDiv, 0);
    zDiv = ",";
    cQuote = quoteChar(zCol);
    appendText(&s, zCol, cQuote);
  }
  appendText(&s, ")", 0);
  sqlite3_finalize(pStmt);
  if( nRow==0 ){
    freeText(&s);
    s.z = 0;
  }
  return s.z;
}

/*
** SQL function:  shell_module_schema(X)
**
** Return a fake schema for the table-valued function or eponymous virtual
** table X.
*/
static void shellModuleSchema(
  sqlite3_context *pCtx,
  int nVal,
  sqlite3_value **apVal
){
  const char *zName = (const char*)sqlite3_value_text(apVal[0]);
  char *zFake = shellFakeSchema(sqlite3_context_db_handle(pCtx), 0, zName);
  if( zFake ){
    sqlite3_result_text(pCtx, sqlite3_mprintf("/* %z */", zFake),
                        -1, sqlite3_free);
  }
}

/*
** SQL function:  shell_add_schema(S,X)
**
** Add the schema name X to the CREATE statement in S and return the result.
** Examples:
**

     "VIEW",
     "TRIGGER",
     "VIRTUAL TABLE"
  };
  int i = 0;
  const char *zIn = (const char*)sqlite3_value_text(apVal[0]);
  const char *zSchema = (const char*)sqlite3_value_text(apVal[1]);
  const char *zName = (const char*)sqlite3_value_text(apVal[2]);
  sqlite3 *db = sqlite3_context_db_handle(pCtx);
  if( zIn!=0 && strncmp(zIn, "CREATE ", 7)==0 ){
    for(i=0; i<(int)(sizeof(aPrefix)/sizeof(aPrefix[0])); i++){
      int n = strlen30(aPrefix[i]);
      if( strncmp(zIn+7, aPrefix[i], n)==0 && zIn[n+7]==' ' ){
        char *z = 0;
        char *zFake = 0;
        if( zSchema ){
          char cQuote = quoteChar(zSchema);
          if( cQuote && sqlite3_stricmp(zSchema,"temp")!=0 ){
            z = sqlite3_mprintf("%.*s \"%w\".%s", n+7, zIn, zSchema, zIn+n+8);
          }else{
            z = sqlite3_mprintf("%.*s %s.%s", n+7, zIn, zSchema, zIn+n+8);
          }
        }
        if( zName
         && aPrefix[i][0]=='V'
         && (zFake = shellFakeSchema(db, zSchema, zName))!=0
        ){
          if( z==0 ){
            z = sqlite3_mprintf("%s\n/* %z */", zIn, zFake);
          }else{
            z = sqlite3_mprintf("%z\n/* %z */", z, zFake);
          }
        }
        if( z ){
          sqlite3_result_text(pCtx, z, -1, sqlite3_free);
          return;
        }
      }
    }
  }
  sqlite3_result_value(pCtx, apVal[0]);
}

/*
** The source code for several run-time loadable extensions is inserted
** below by the ../tool/mkshellc.tcl script.  Before processing that included
** code, we need to override some macros to make the included program code
** work here in the middle of this regular program.
*/
#define SQLITE_EXTENSION_INIT1
#define SQLITE_EXTENSION_INIT2(X) (void)(X)

#if defined(_WIN32) && defined(_MSC_VER)
/************************* Begin test_windirent.c ******************/
/*
** 2015 November 30
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code to implement most of the opendir() family of
** POSIX functions on Win32 using the MSVCRT.
*/

#if defined(_WIN32) && defined(_MSC_VER)

#include "test_windirent.h"

/*
** Implementation of the POSIX getenv() function using the Win32 API.
** This function is not thread-safe.
*/
const char *windirent_getenv(
  const char *name
){
  static char value[32768]; /* Maximum length, per MSDN */
  DWORD dwSize = sizeof(value) / sizeof(char); /* Size in chars */
  DWORD dwRet; /* Value returned by GetEnvironmentVariableA() */

  memset(value, 0, sizeof(value));
  dwRet = GetEnvironmentVariableA(name, value, dwSize);
  if( dwRet==0 || dwRet>dwSize ){
    /*
    ** The function call to GetEnvironmentVariableA() failed -OR-
    ** the buffer is not large enough.  Either way, return NULL.
    */
    return 0;
  }else{
    /*
    ** The function call to GetEnvironmentVariableA() succeeded
    ** -AND- the buffer contains the entire value.
    */
    return value;
  }
}

/*
** Implementation of the POSIX opendir() function using the MSVCRT.
*/
LPDIR opendir(
  const char *dirname
){
  struct _finddata_t data;
  LPDIR dirp = (LPDIR)sqlite3_malloc(sizeof(DIR));
  SIZE_T namesize = sizeof(data.name) / sizeof(data.name[0]);

  if( dirp==NULL ) return NULL;
  memset(dirp, 0, sizeof(DIR));

  /* TODO: Remove this if Unix-style root paths are not used. */
  if( sqlite3_stricmp(dirname, "/")==0 ){
    dirname = windirent_getenv("SystemDrive");
  }

  memset(&data, 0, sizeof(struct _finddata_t));
  _snprintf(data.name, namesize, "%s\\*", dirname);
  dirp->d_handle = _findfirst(data.name, &data);

  if( dirp->d_handle==BAD_INTPTR_T ){
    closedir(dirp);
    return NULL;
  }

  /* TODO: Remove this block to allow hidden and/or system files. */
  if( is_filtered(data) ){
next:

    memset(&data, 0, sizeof(struct _finddata_t));
    if( _findnext(dirp->d_handle, &data)==-1 ){
      closedir(dirp);
      return NULL;
    }

    /* TODO: Remove this block to allow hidden and/or system files. */
    if( is_filtered(data) ) goto next;
  }

  dirp->d_first.d_attributes = data.attrib;
  strncpy(dirp->d_first.d_name, data.name, NAME_MAX);
  dirp->d_first.d_name[NAME_MAX] = '\0';

  return dirp;
}

/*
** Implementation of the POSIX readdir() function using the MSVCRT.
*/
LPDIRENT readdir(
  LPDIR dirp
){
  struct _finddata_t data;

  if( dirp==NULL ) return NULL;

  if( dirp->d_first.d_ino==0 ){
    dirp->d_first.d_ino++;
    dirp->d_next.d_ino++;

    return &dirp->d_first;
  }

next:

  memset(&data, 0, sizeof(struct _finddata_t));
  if( _findnext(dirp->d_handle, &data)==-1 ) return NULL;

  /* TODO: Remove this block to allow hidden and/or system files. */
  if( is_filtered(data) ) goto next;

  dirp->d_next.d_ino++;
  dirp->d_next.d_attributes = data.attrib;
  strncpy(dirp->d_next.d_name, data.name, NAME_MAX);
  dirp->d_next.d_name[NAME_MAX] = '\0';

  return &dirp->d_next;
}

/*
** Implementation of the POSIX readdir_r() function using the MSVCRT.
*/
INT readdir_r(
  LPDIR dirp,
  LPDIRENT entry,
  LPDIRENT *result
){
  struct _finddata_t data;

  if( dirp==NULL ) return EBADF;

  if( dirp->d_first.d_ino==0 ){
    dirp->d_first.d_ino++;
    dirp->d_next.d_ino++;

    entry->d_ino = dirp->d_first.d_ino;
    entry->d_attributes = dirp->d_first.d_attributes;
    strncpy(entry->d_name, dirp->d_first.d_name, NAME_MAX);
    entry->d_name[NAME_MAX] = '\0';

    *result = entry;
    return 0;
  }

next:

  memset(&data, 0, sizeof(struct _finddata_t));
  if( _findnext(dirp->d_handle, &data)==-1 ){
    *result = NULL;
    return ENOENT;
  }

  /* TODO: Remove this block to allow hidden and/or system files. */
  if( is_filtered(data) ) goto next;

  entry->d_ino = (ino_t)-1; /* not available */
  entry->d_attributes = data.attrib;
  strncpy(entry->d_name, data.name, NAME_MAX);
  entry->d_name[NAME_MAX] = '\0';

  *result = entry;
  return 0;
}

/*
** Implementation of the POSIX closedir() function using the MSVCRT.
*/
INT closedir(
  LPDIR dirp
){
  INT result = 0;

  if( dirp==NULL ) return EINVAL;

  if( dirp->d_handle!=NULL_INTPTR_T && dirp->d_handle!=BAD_INTPTR_T ){
    result = _findclose(dirp->d_handle);
  }

  sqlite3_free(dirp);
  return result;
}

#endif /* defined(WIN32) && defined(_MSC_VER) */

/************************* End test_windirent.c ********************/
#define dirent DIRENT
#endif
/************************* Begin ../ext/misc/shathree.c ******************/
/*
** 2017-03-08
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**

** is used.  If SIZE is included it must be one of the integers 224, 256,
** 384, or 512, to determine SHA3 hash variant that is computed.
*/
SQLITE_EXTENSION_INIT1
#include <assert.h>
#include <string.h>
#include <stdarg.h>
/* typedef sqlite3_uint64 u64; */

/******************************************************************************
** The Hash Engine
*/
/*
** Macros to determine whether the machine is big or little endian,
** and whether or not that determination is run-time or compile-time.

};

/*
** A single step of the Keccak mixing function for a 1600-bit state
*/
static void KeccakF1600Step(SHA3Context *p){
  int i;
  u64 b0, b1, b2, b3, b4;
  u64 c0, c1, c2, c3, c4;
  u64 d0, d1, d2, d3, d4;
  static const u64 RC[] = {
    0x0000000000000001ULL,  0x0000000000008082ULL,
    0x800000000000808aULL,  0x8000000080008000ULL,
    0x000000000000808bULL,  0x0000000080000001ULL,
    0x8000000080008081ULL,  0x8000000000008009ULL,
    0x000000000000008aULL,  0x0000000000000088ULL,
    0x0000000080008009ULL,  0x000000008000000aULL,
    0x000000008000808bULL,  0x800000000000008bULL,
    0x8000000000008089ULL,  0x8000000000008003ULL,
    0x8000000000008002ULL,  0x8000000000000080ULL,
    0x000000000000800aULL,  0x800000008000000aULL,
    0x8000000080008081ULL,  0x8000000000008080ULL,
    0x0000000080000001ULL,  0x8000000080008008ULL
  };
# define a00 (p->u.s[0])
# define a01 (p->u.s[1])
# define a02 (p->u.s[2])
# define a03 (p->u.s[3])
# define a04 (p->u.s[4])
# define a10 (p->u.s[5])
# define a11 (p->u.s[6])
# define a12 (p->u.s[7])
# define a13 (p->u.s[8])
# define a14 (p->u.s[9])
# define a20 (p->u.s[10])
# define a21 (p->u.s[11])
# define a22 (p->u.s[12])
# define a23 (p->u.s[13])
# define a24 (p->u.s[14])
# define a30 (p->u.s[15])
# define a31 (p->u.s[16])
# define a32 (p->u.s[17])
# define a33 (p->u.s[18])
# define a34 (p->u.s[19])
# define a40 (p->u.s[20])
# define a41 (p->u.s[21])
# define a42 (p->u.s[22])
# define a43 (p->u.s[23])
# define a44 (p->u.s[24])
# define ROL64(a,x) ((a<<x)|(a>>(64-x)))

  for(i=0; i<24; i+=4){
    c0 = a00^a10^a20^a30^a40;
    c1 = a01^a11^a21^a31^a41;
    c2 = a02^a12^a22^a32^a42;
    c3 = a03^a13^a23^a33^a43;
    c4 = a04^a14^a24^a34^a44;
    d0 = c4^ROL64(c1, 1);
    d1 = c0^ROL64(c2, 1);
    d2 = c1^ROL64(c3, 1);
    d3 = c2^ROL64(c4, 1);
    d4 = c3^ROL64(c0, 1);

    b0 = (a00^d0);
    b1 = ROL64((a11^d1), 44);
    b2 = ROL64((a22^d2), 43);
    b3 = ROL64((a33^d3), 21);
    b4 = ROL64((a44^d4), 14);
    a00 =   b0 ^((~b1)&  b2 );
    a00 ^= RC[i];
    a11 =   b1 ^((~b2)&  b3 );
    a22 =   b2 ^((~b3)&  b4 );
    a33 =   b3 ^((~b4)&  b0 );
    a44 =   b4 ^((~b0)&  b1 );

    b2 = ROL64((a20^d0), 3);
    b3 = ROL64((a31^d1), 45);
    b4 = ROL64((a42^d2), 61);
    b0 = ROL64((a03^d3), 28);
    b1 = ROL64((a14^d4), 20);
    a20 =   b0 ^((~b1)&  b2 );
    a31 =   b1 ^((~b2)&  b3 );
    a42 =   b2 ^((~b3)&  b4 );
    a03 =   b3 ^((~b4)&  b0 );
    a14 =   b4 ^((~b0)&  b1 );

    b4 = ROL64((a40^d0), 18);
    b0 = ROL64((a01^d1), 1);
    b1 = ROL64((a12^d2), 6);
    b2 = ROL64((a23^d3), 25);
    b3 = ROL64((a34^d4), 8);
    a40 =   b0 ^((~b1)&  b2 );
    a01 =   b1 ^((~b2)&  b3 );
    a12 =   b2 ^((~b3)&  b4 );
    a23 =   b3 ^((~b4)&  b0 );
    a34 =   b4 ^((~b0)&  b1 );

    b1 = ROL64((a10^d0), 36);
    b2 = ROL64((a21^d1), 10);
    b3 = ROL64((a32^d2), 15);
    b4 = ROL64((a43^d3), 56);
    b0 = ROL64((a04^d4), 27);
    a10 =   b0 ^((~b1)&  b2 );
    a21 =   b1 ^((~b2)&  b3 );
    a32 =   b2 ^((~b3)&  b4 );
    a43 =   b3 ^((~b4)&  b0 );
    a04 =   b4 ^((~b0)&  b1 );

    b3 = ROL64((a30^d0), 41);
    b4 = ROL64((a41^d1), 2);
    b0 = ROL64((a02^d2), 62);
    b1 = ROL64((a13^d3), 55);
    b2 = ROL64((a24^d4), 39);
    a30 =   b0 ^((~b1)&  b2 );
    a41 =   b1 ^((~b2)&  b3 );
    a02 =   b2 ^((~b3)&  b4 );
    a13 =   b3 ^((~b4)&  b0 );
    a24 =   b4 ^((~b0)&  b1 );

    c0 = a00^a20^a40^a10^a30;
    c1 = a11^a31^a01^a21^a41;
    c2 = a22^a42^a12^a32^a02;
    c3 = a33^a03^a23^a43^a13;
    c4 = a44^a14^a34^a04^a24;
    d0 = c4^ROL64(c1, 1);
    d1 = c0^ROL64(c2, 1);
    d2 = c1^ROL64(c3, 1);
    d3 = c2^ROL64(c4, 1);
    d4 = c3^ROL64(c0, 1);

    b0 = (a00^d0);
    b1 = ROL64((a31^d1), 44);
    b2 = ROL64((a12^d2), 43);
    b3 = ROL64((a43^d3), 21);
    b4 = ROL64((a24^d4), 14);
    a00 =   b0 ^((~b1)&  b2 );
    a00 ^= RC[i+1];
    a31 =   b1 ^((~b2)&  b3 );
    a12 =   b2 ^((~b3)&  b4 );
    a43 =   b3 ^((~b4)&  b0 );
    a24 =   b4 ^((~b0)&  b1 );

    b2 = ROL64((a40^d0), 3);
    b3 = ROL64((a21^d1), 45);
    b4 = ROL64((a02^d2), 61);
    b0 = ROL64((a33^d3), 28);
    b1 = ROL64((a14^d4), 20);
    a40 =   b0 ^((~b1)&  b2 );
    a21 =   b1 ^((~b2)&  b3 );
    a02 =   b2 ^((~b3)&  b4 );
    a33 =   b3 ^((~b4)&  b0 );

    a14 =   b4 ^((~b0)&  b1 );

    b4 = ROL64((a30^d0), 18);
    b0 = ROL64((a11^d1), 1);
    b1 = ROL64((a42^d2), 6);
    b2 = ROL64((a23^d3), 25);
    b3 = ROL64((a04^d4), 8);
    a30 =   b0 ^((~b1)&  b2 );
    a11 =   b1 ^((~b2)&  b3 );
    a42 =   b2 ^((~b3)&  b4 );
    a23 =   b3 ^((~b4)&  b0 );
    a04 =   b4 ^((~b0)&  b1 );

    b1 = ROL64((a20^d0), 36);
    b2 = ROL64((a01^d1), 10);
    b3 = ROL64((a32^d2), 15);
    b4 = ROL64((a13^d3), 56);
    b0 = ROL64((a44^d4), 27);
    a20 =   b0 ^((~b1)&  b2 );
    a01 =   b1 ^((~b2)&  b3 );
    a32 =   b2 ^((~b3)&  b4 );
    a13 =   b3 ^((~b4)&  b0 );
    a44 =   b4 ^((~b0)&  b1 );

    b3 = ROL64((a10^d0), 41);
    b4 = ROL64((a41^d1), 2);
    b0 = ROL64((a22^d2), 62);
    b1 = ROL64((a03^d3), 55);
    b2 = ROL64((a34^d4), 39);
    a10 =   b0 ^((~b1)&  b2 );
    a41 =   b1 ^((~b2)&  b3 );
    a22 =   b2 ^((~b3)&  b4 );
    a03 =   b3 ^((~b4)&  b0 );
    a34 =   b4 ^((~b0)&  b1 );

    c0 = a00^a40^a30^a20^a10;
    c1 = a31^a21^a11^a01^a41;
    c2 = a12^a02^a42^a32^a22;
    c3 = a43^a33^a23^a13^a03;
    c4 = a24^a14^a04^a44^a34;
    d0 = c4^ROL64(c1, 1);
    d1 = c0^ROL64(c2, 1);
    d2 = c1^ROL64(c3, 1);
    d3 = c2^ROL64(c4, 1);
    d4 = c3^ROL64(c0, 1);

    b0 = (a00^d0);
    b1 = ROL64((a21^d1), 44);
    b2 = ROL64((a42^d2), 43);
    b3 = ROL64((a13^d3), 21);
    b4 = ROL64((a34^d4), 14);
    a00 =   b0 ^((~b1)&  b2 );
    a00 ^= RC[i+2];
    a21 =   b1 ^((~b2)&  b3 );
    a42 =   b2 ^((~b3)&  b4 );
    a13 =   b3 ^((~b4)&  b0 );
    a34 =   b4 ^((~b0)&  b1 );

    b2 = ROL64((a30^d0), 3);
    b3 = ROL64((a01^d1), 45);
    b4 = ROL64((a22^d2), 61);
    b0 = ROL64((a43^d3), 28);
    b1 = ROL64((a14^d4), 20);
    a30 =   b0 ^((~b1)&  b2 );
    a01 =   b1 ^((~b2)&  b3 );
    a22 =   b2 ^((~b3)&  b4 );
    a43 =   b3 ^((~b4)&  b0 );

    a14 =   b4 ^((~b0)&  b1 );

    b4 = ROL64((a10^d0), 18);
    b0 = ROL64((a31^d1), 1);
    b1 = ROL64((a02^d2), 6);
    b2 = ROL64((a23^d3), 25);
    b3 = ROL64((a44^d4), 8);
    a10 =   b0 ^((~b1)&  b2 );
    a31 =   b1 ^((~b2)&  b3 );
    a02 =   b2 ^((~b3)&  b4 );
    a23 =   b3 ^((~b4)&  b0 );
    a44 =   b4 ^((~b0)&  b1 );

    b1 = ROL64((a40^d0), 36);
    b2 = ROL64((a11^d1), 10);
    b3 = ROL64((a32^d2), 15);
    b4 = ROL64((a03^d3), 56);
    b0 = ROL64((a24^d4), 27);
    a40 =   b0 ^((~b1)&  b2 );
    a11 =   b1 ^((~b2)&  b3 );
    a32 =   b2 ^((~b3)&  b4 );
    a03 =   b3 ^((~b4)&  b0 );
    a24 =   b4 ^((~b0)&  b1 );

    b3 = ROL64((a20^d0), 41);
    b4 = ROL64((a41^d1), 2);
    b0 = ROL64((a12^d2), 62);
    b1 = ROL64((a33^d3), 55);
    b2 = ROL64((a04^d4), 39);
    a20 =   b0 ^((~b1)&  b2 );
    a41 =   b1 ^((~b2)&  b3 );
    a12 =   b2 ^((~b3)&  b4 );
    a33 =   b3 ^((~b4)&  b0 );
    a04 =   b4 ^((~b0)&  b1 );

    c0 = a00^a30^a10^a40^a20;
    c1 = a21^a01^a31^a11^a41;
    c2 = a42^a22^a02^a32^a12;
    c3 = a13^a43^a23^a03^a33;
    c4 = a34^a14^a44^a24^a04;
    d0 = c4^ROL64(c1, 1);
    d1 = c0^ROL64(c2, 1);
    d2 = c1^ROL64(c3, 1);
    d3 = c2^ROL64(c4, 1);
    d4 = c3^ROL64(c0, 1);

    b0 = (a00^d0);
    b1 = ROL64((a01^d1), 44);
    b2 = ROL64((a02^d2), 43);
    b3 = ROL64((a03^d3), 21);
    b4 = ROL64((a04^d4), 14);
    a00 =   b0 ^((~b1)&  b2 );
    a00 ^= RC[i+3];
    a01 =   b1 ^((~b2)&  b3 );
    a02 =   b2 ^((~b3)&  b4 );
    a03 =   b3 ^((~b4)&  b0 );
    a04 =   b4 ^((~b0)&  b1 );

    b2 = ROL64((a10^d0), 3);
    b3 = ROL64((a11^d1), 45);
    b4 = ROL64((a12^d2), 61);
    b0 = ROL64((a13^d3), 28);
    b1 = ROL64((a14^d4), 20);
    a10 =   b0 ^((~b1)&  b2 );
    a11 =   b1 ^((~b2)&  b3 );
    a12 =   b2 ^((~b3)&  b4 );
    a13 =   b3 ^((~b4)&  b0 );

    a14 =   b4 ^((~b0)&  b1 );

    b4 = ROL64((a20^d0), 18);
    b0 = ROL64((a21^d1), 1);
    b1 = ROL64((a22^d2), 6);
    b2 = ROL64((a23^d3), 25);
    b3 = ROL64((a24^d4), 8);
    a20 =   b0 ^((~b1)&  b2 );
    a21 =   b1 ^((~b2)&  b3 );
    a22 =   b2 ^((~b3)&  b4 );
    a23 =   b3 ^((~b4)&  b0 );
    a24 =   b4 ^((~b0)&  b1 );

    b1 = ROL64((a30^d0), 36);
    b2 = ROL64((a31^d1), 10);
    b3 = ROL64((a32^d2), 15);
    b4 = ROL64((a33^d3), 56);
    b0 = ROL64((a34^d4), 27);
    a30 =   b0 ^((~b1)&  b2 );
    a31 =   b1 ^((~b2)&  b3 );
    a32 =   b2 ^((~b3)&  b4 );
    a33 =   b3 ^((~b4)&  b0 );
    a34 =   b4 ^((~b0)&  b1 );

    b3 = ROL64((a40^d0), 41);
    b4 = ROL64((a41^d1), 2);
    b0 = ROL64((a42^d2), 62);
    b1 = ROL64((a43^d3), 55);
    b2 = ROL64((a44^d4), 39);
    a40 =   b0 ^((~b1)&  b2 );
    a41 =   b1 ^((~b2)&  b3 );
    a42 =   b2 ^((~b3)&  b4 );
    a43 =   b3 ^((~b4)&  b0 );
    a44 =   b4 ^((~b0)&  b1 );
  }
}

/*
** Initialize a new hash.  iSize determines the size of the hash
** in bits and should be one of 224, 256, 384, or 512.  Or iSize
** can be zero to use the default hash size of 256 bits.

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This SQLite extension implements SQL functions readfile() and
** writefile(), and eponymous virtual type "fsdir".
**
** WRITEFILE(FILE, DATA [, MODE [, MTIME]]):
**
**   If neither of the optional arguments is present, then this UDF
**   function writes blob DATA to file FILE. If successful, the number
**   of bytes written is returned. If an error occurs, NULL is returned.
**
**   If the first option argument - MODE - is present, then it must
**   be passed an integer value that corresponds to a POSIX mode
**   value (file type + permissions, as returned in the stat.st_mode
**   field by the stat() system call). Three types of files may
**   be written/created:
**
**     regular files:  (mode & 0170000)==0100000
**     symbolic links: (mode & 0170000)==0120000
**     directories:    (mode & 0170000)==0040000
**
**   For a directory, the DATA is ignored. For a symbolic link, it is
**   interpreted as text and used as the target of the link. For a
**   regular file, it is interpreted as a blob and written into the
**   named file. Regardless of the type of file, its permissions are
**   set to (mode & 0777) before returning.
**
**   If the optional MTIME argument is present, then it is interpreted
**   as an integer - the number of seconds since the unix epoch. The
**   modification-time of the target file is set to this value before
**   returning.
**
**   If three or more arguments are passed to this function and an
**   error is encountered, an exception is raised.
**
** READFILE(FILE):
**
**   Read and return the contents of file FILE (type blob) from disk.
**
** FSDIR:
**
**   Used as follows:
**
**     SELECT * FROM fsdir($path [, $dir]);
**
**   Parameter $path is an absolute or relative pathname. If the file that it
**   refers to does not exist, it is an error. If the path refers to a regular
**   file or symbolic link, it returns a single row. Or, if the path refers
**   to a directory, it returns one row for the directory, and one row for each
**   file within the hierarchy rooted at $path.
**
**   Each row has the following columns:
**
**     name:  Path to file or directory (text value).
**     mode:  Value of stat.st_mode for directory entry (an integer).
**     mtime: Value of stat.st_mtime for directory entry (an integer).
**     data:  For a regular file, a blob containing the file data. For a
**            symlink, a text value containing the text of the link. For a
**            directory, NULL.
**
**   If a non-NULL value is specified for the optional $dir parameter and
**   $path is a relative path, then $path is interpreted relative to $dir. 
**   And the paths returned in the "name" column of the table are also 
**   relative to directory $dir.
*/
SQLITE_EXTENSION_INIT1
#include <stdio.h>
#include <string.h>
#include <assert.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#if !defined(_WIN32) && !defined(WIN32)
#  include <unistd.h>
#  include <dirent.h>
#  include <utime.h>
#else
#  include "windows.h"
#  include <io.h>
#  include <direct.h>
#  include "test_windirent.h"
#  define dirent DIRENT
#  define timespec TIMESPEC
#  define stat _stat
#  define mkdir(path,mode) _mkdir(path)
#  define lstat(path,buf) _stat(path,buf)
#endif
#include <time.h>
#include <errno.h>


#define FSDIR_SCHEMA "(name,mode,mtime,data,path HIDDEN,dir HIDDEN)"

/*
** Set the result stored by context ctx to a blob containing the 
** contents of file zName.
*/
static void readFileContents(sqlite3_context *ctx, const char *zName){
  FILE *in;
  long nIn;
  void *pBuf;

  in = fopen(zName, "rb");
  if( in==0 ) return;
  fseek(in, 0, SEEK_END);
  nIn = ftell(in);
  rewind(in);
  pBuf = sqlite3_malloc( nIn );
  if( pBuf && 1==fread(pBuf, nIn, 1, in) ){
    sqlite3_result_blob(ctx, pBuf, nIn, sqlite3_free);
  }else{
    sqlite3_free(pBuf);
  }
  fclose(in);
}

/*
** Implementation of the "readfile(X)" SQL function.  The entire content
** of the file named X is read and returned as a BLOB.  NULL is returned
** if the file does not exist or is unreadable.
*/
static void readfileFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  const char *zName;




  (void)(argc);  /* Unused parameter */
  zName = (const char*)sqlite3_value_text(argv[0]);
  if( zName==0 ) return;
  readFileContents(context, zName);
}

/*
** Set the error message contained in context ctx to the results of
** vprintf(zFmt, ...).
*/
static void ctxErrorMsg(sqlite3_context *ctx, const char *zFmt, ...){
  char *zMsg = 0;
  va_list ap;
  va_start(ap, zFmt);
  zMsg = sqlite3_vmprintf(zFmt, ap);
  sqlite3_result_error(ctx, zMsg, -1);
  sqlite3_free(zMsg);
  va_end(ap);
}

/*
** Argument zFile is the name of a file that will be created and/or written
** by SQL function writefile(). This function ensures that the directory
** zFile will be written to exists, creating it if required. The permissions
** for any path components created by this function are set to (mode&0777).
**
** If an OOM condition is encountered, SQLITE_NOMEM is returned. Otherwise,
** SQLITE_OK is returned if the directory is successfully created, or
** SQLITE_ERROR otherwise.
*/
static int makeDirectory(
  const char *zFile,
  mode_t mode
){
  char *zCopy = sqlite3_mprintf("%s", zFile);
  int rc = SQLITE_OK;

  if( zCopy==0 ){
    rc = SQLITE_NOMEM;
  }else{
    int nCopy = (int)strlen(zCopy);
    int i = 1;

    while( rc==SQLITE_OK ){
      struct stat sStat;
      int rc2;

      for(; zCopy[i]!='/' && i<nCopy; i++);
      if( i==nCopy ) break;
      zCopy[i] = '\0';

      rc2 = stat(zCopy, &sStat);
      if( rc2!=0 ){
        if( mkdir(zCopy, mode & 0777) ) rc = SQLITE_ERROR;
      }else{
        if( !S_ISDIR(sStat.st_mode) ) rc = SQLITE_ERROR;
      }
      zCopy[i] = '/';
      i++;
    }

    sqlite3_free(zCopy);
  }

  return rc;
}

/*
** This function does the work for the writefile() UDF. Refer to 
** header comments at the top of this file for details.
*/
static int writeFile(
  sqlite3_context *pCtx,          /* Context to return bytes written in */
  const char *zFile,              /* File to write */
  sqlite3_value *pData,           /* Data to write */
  mode_t mode,                    /* MODE parameter passed to writefile() */
  sqlite3_int64 mtime             /* MTIME parameter (or -1 to not set time) */
){
#if !defined(_WIN32) && !defined(WIN32)
  if( S_ISLNK(mode) ){
    const char *zTo = (const char*)sqlite3_value_text(pData);
    if( symlink(zTo, zFile)<0 ) return 1;
  }else
#endif
  {
    if( S_ISDIR(mode) ){
      if( mkdir(zFile, mode) ){
        /* The mkdir() call to create the directory failed. This might not
        ** be an error though - if there is already a directory at the same
        ** path and either the permissions already match or can be changed
        ** to do so using chmod(), it is not an error.  */
        struct stat sStat;
        if( errno!=EEXIST
         || 0!=stat(zFile, &sStat)
         || !S_ISDIR(sStat.st_mode)
         || ((sStat.st_mode&0777)!=(mode&0777) && 0!=chmod(zFile, mode&0777))
        ){
          return 1;
        }
      }
    }else{
      sqlite3_int64 nWrite = 0;
      const char *z;
      int rc = 0;
      FILE *out = fopen(zFile, "wb");
      if( out==0 ) return 1;
      z = (const char*)sqlite3_value_blob(pData);
      if( z ){
        sqlite3_int64 n = fwrite(z, 1, sqlite3_value_bytes(pData), out);
        nWrite = sqlite3_value_bytes(pData);
        if( nWrite!=n ){
          rc = 1;
        }
      }
      fclose(out);
      if( rc==0 && mode && chmod(zFile, mode & 0777) ){
        rc = 1;
      }
      if( rc ) return 2;
      sqlite3_result_int64(pCtx, nWrite);
    }
  }

  if( mtime>=0 ){
#if !defined(_WIN32) && !defined(WIN32)
    struct timespec times[2];
    times[0].tv_nsec = times[1].tv_nsec = 0;
    times[0].tv_sec = time(0);
    times[1].tv_sec = mtime;
    if( utimensat(AT_FDCWD, zFile, times, AT_SYMLINK_NOFOLLOW) ){
      return 1;
    }
#else
    FILETIME lastAccess;
    FILETIME lastWrite;
    SYSTEMTIME currentTime;
    LONGLONG intervals;
    HANDLE hFile;
    GetSystemTime(&currentTime);
    SystemTimeToFileTime(&currentTime, &lastAccess);
    intervals = Int32x32To64(mtime, 10000000) + 116444736000000000;
    lastWrite.dwLowDateTime = (DWORD)intervals;
    lastWrite.dwHighDateTime = intervals >> 32;
    hFile = CreateFile(
      zFile, FILE_WRITE_ATTRIBUTES, 0, NULL, OPEN_EXISTING,
      FILE_FLAG_BACKUP_SEMANTICS, NULL
    );
    if( hFile!=INVALID_HANDLE_VALUE ){
      BOOL bResult = SetFileTime(hFile, NULL, &lastAccess, &lastWrite);
      CloseHandle(hFile);
      return !bResult;
    }else{
      return 1;
    }
#endif
  }

  return 0;
}

/*
** Implementation of the "writefile(W,X[,Y[,Z]]])" SQL function.  



** Refer to header comments at the top of this file for details.
*/
static void writefileFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){

  const char *zFile;
  mode_t mode = 0;
  int res;
  sqlite3_int64 mtime = -1;

  if( argc<2 || argc>4 ){
    sqlite3_result_error(context, 
        "wrong number of arguments to function writefile()", -1
    );
    return;
  }

  zFile = (const char*)sqlite3_value_text(argv[0]);
  if( zFile==0 ) return;
  if( argc>=3 ){
    mode = (mode_t)sqlite3_value_int(argv[2]);
  }
  if( argc==4 ){
    mtime = sqlite3_value_int64(argv[3]);
  }

  res = writeFile(context, zFile, argv[1], mode, mtime);
  if( res==1 && errno==ENOENT ){
    if( makeDirectory(zFile, mode)==SQLITE_OK ){
      res = writeFile(context, zFile, argv[1], mode, mtime);
    }
  }

  if( argc>2 && res!=0 ){
    if( S_ISLNK(mode) ){
      ctxErrorMsg(context, "failed to create symlink: %s", zFile);
    }else if( S_ISDIR(mode) ){
      ctxErrorMsg(context, "failed to create directory: %s", zFile);
    }else{
      ctxErrorMsg(context, "failed to write file: %s", zFile);
    }
  }
}

#ifndef SQLITE_OMIT_VIRTUALTABLE

/* 
** Cursor type for recursively iterating through a directory structure.
*/
typedef struct fsdir_cursor fsdir_cursor;
typedef struct FsdirLevel FsdirLevel;

struct FsdirLevel {
  DIR *pDir;                 /* From opendir() */
  char *zDir;                /* Name of directory (nul-terminated) */
};

struct fsdir_cursor {
  sqlite3_vtab_cursor base;  /* Base class - must be first */

  int nLvl;                  /* Number of entries in aLvl[] array */
  int iLvl;                  /* Index of current entry */
  FsdirLevel *aLvl;          /* Hierarchy of directories being traversed */

  const char *zBase;
  int nBase;

  struct stat sStat;         /* Current lstat() results */
  char *zPath;               /* Path to current entry */
  sqlite3_int64 iRowid;      /* Current rowid */
};

typedef struct fsdir_tab fsdir_tab;
struct fsdir_tab {
  sqlite3_vtab base;         /* Base class - must be first */
};

/*
** Construct a new fsdir virtual table object.
*/
static int fsdirConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  fsdir_tab *pNew = 0;
  int rc;

  rc = sqlite3_declare_vtab(db, "CREATE TABLE x" FSDIR_SCHEMA);
  if( rc==SQLITE_OK ){
    pNew = (fsdir_tab*)sqlite3_malloc( sizeof(*pNew) );
    if( pNew==0 ) return SQLITE_NOMEM;
    memset(pNew, 0, sizeof(*pNew));
  }
  *ppVtab = (sqlite3_vtab*)pNew;
  return rc;
}

/*
** This method is the destructor for fsdir vtab objects.
*/
static int fsdirDisconnect(sqlite3_vtab *pVtab){
  sqlite3_free(pVtab);
  return SQLITE_OK;
}

/*
** Constructor for a new fsdir_cursor object.
*/
static int fsdirOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
  fsdir_cursor *pCur;
  pCur = sqlite3_malloc( sizeof(*pCur) );
  if( pCur==0 ) return SQLITE_NOMEM;
  memset(pCur, 0, sizeof(*pCur));
  pCur->iLvl = -1;
  *ppCursor = &pCur->base;
  return SQLITE_OK;
}

/*
** Reset a cursor back to the state it was in when first returned
** by fsdirOpen().
*/
static void fsdirResetCursor(fsdir_cursor *pCur){
  int i;
  for(i=0; i<=pCur->iLvl; i++){
    FsdirLevel *pLvl = &pCur->aLvl[i];
    if( pLvl->pDir ) closedir(pLvl->pDir);
    sqlite3_free(pLvl->zDir);
  }
  sqlite3_free(pCur->zPath);
  pCur->aLvl = 0;
  pCur->zPath = 0;
  pCur->zBase = 0;
  pCur->nBase = 0;
  pCur->iLvl = -1;
  pCur->iRowid = 1;
}

/*
** Destructor for an fsdir_cursor.
*/
static int fsdirClose(sqlite3_vtab_cursor *cur){
  fsdir_cursor *pCur = (fsdir_cursor*)cur;

  fsdirResetCursor(pCur);
  sqlite3_free(pCur->aLvl);
  sqlite3_free(pCur);
  return SQLITE_OK;
}

/*
** Set the error message for the virtual table associated with cursor
** pCur to the results of vprintf(zFmt, ...).
*/
static void fsdirSetErrmsg(fsdir_cursor *pCur, const char *zFmt, ...){
  va_list ap;
  va_start(ap, zFmt);
  pCur->base.pVtab->zErrMsg = sqlite3_vmprintf(zFmt, ap);
  va_end(ap);
}


/*
** Advance an fsdir_cursor to its next row of output.
*/
static int fsdirNext(sqlite3_vtab_cursor *cur){
  fsdir_cursor *pCur = (fsdir_cursor*)cur;
  mode_t m = pCur->sStat.st_mode;

  pCur->iRowid++;
  if( S_ISDIR(m) ){
    /* Descend into this directory */
    int iNew = pCur->iLvl + 1;
    FsdirLevel *pLvl;
    if( iNew>=pCur->nLvl ){
      int nNew = iNew+1;
      int nByte = nNew*sizeof(FsdirLevel);
      FsdirLevel *aNew = (FsdirLevel*)sqlite3_realloc(pCur->aLvl, nByte);
      if( aNew==0 ) return SQLITE_NOMEM;
      memset(&aNew[pCur->nLvl], 0, sizeof(FsdirLevel)*(nNew-pCur->nLvl));
      pCur->aLvl = aNew;
      pCur->nLvl = nNew;
    }
    pCur->iLvl = iNew;
    pLvl = &pCur->aLvl[iNew];
    
    pLvl->zDir = pCur->zPath;
    pCur->zPath = 0;
    pLvl->pDir = opendir(pLvl->zDir);
    if( pLvl->pDir==0 ){
      fsdirSetErrmsg(pCur, "cannot read directory: %s", pCur->zPath);
      return SQLITE_ERROR;
    }
  }

  while( pCur->iLvl>=0 ){
    FsdirLevel *pLvl = &pCur->aLvl[pCur->iLvl];
    struct dirent *pEntry = readdir(pLvl->pDir);
    if( pEntry ){
      if( pEntry->d_name[0]=='.' ){
       if( pEntry->d_name[1]=='.' && pEntry->d_name[2]=='\0' ) continue;
       if( pEntry->d_name[1]=='\0' ) continue;
      }
      sqlite3_free(pCur->zPath);
      pCur->zPath = sqlite3_mprintf("%s/%s", pLvl->zDir, pEntry->d_name);
      if( pCur->zPath==0 ) return SQLITE_NOMEM;
      if( lstat(pCur->zPath, &pCur->sStat) ){
        fsdirSetErrmsg(pCur, "cannot stat file: %s", pCur->zPath);
        return SQLITE_ERROR;
      }
      return SQLITE_OK;
    }
    closedir(pLvl->pDir);
    sqlite3_free(pLvl->zDir);
    pLvl->pDir = 0;
    pLvl->zDir = 0;
    pCur->iLvl--;
  }

  /* EOF */
  sqlite3_free(pCur->zPath);
  pCur->zPath = 0;
  return SQLITE_OK;
}

/*
** Return values of columns for the row at which the series_cursor
** is currently pointing.
*/
static int fsdirColumn(
  sqlite3_vtab_cursor *cur,   /* The cursor */
  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
  int i                       /* Which column to return */
){
  fsdir_cursor *pCur = (fsdir_cursor*)cur;
  switch( i ){
    case 0: { /* name */
      sqlite3_result_text(ctx, &pCur->zPath[pCur->nBase], -1, SQLITE_TRANSIENT);
      break;
    }

    case 1: /* mode */
      sqlite3_result_int64(ctx, pCur->sStat.st_mode);
      break;

    case 2: /* mtime */
      sqlite3_result_int64(ctx, pCur->sStat.st_mtime);
      break;

    case 3: { /* data */
      mode_t m = pCur->sStat.st_mode;
      if( S_ISDIR(m) ){
        sqlite3_result_null(ctx);
#if !defined(_WIN32) && !defined(WIN32)
      }else if( S_ISLNK(m) ){
        char aStatic[64];
        char *aBuf = aStatic;
        int nBuf = 64;
        int n;

        while( 1 ){
          n = readlink(pCur->zPath, aBuf, nBuf);
          if( n<nBuf ) break;
          if( aBuf!=aStatic ) sqlite3_free(aBuf);
          nBuf = nBuf*2;
          aBuf = sqlite3_malloc(nBuf);
          if( aBuf==0 ){
            sqlite3_result_error_nomem(ctx);
            return SQLITE_NOMEM;
          }
        }

        sqlite3_result_text(ctx, aBuf, n, SQLITE_TRANSIENT);
        if( aBuf!=aStatic ) sqlite3_free(aBuf);
#endif
      }else{
        readFileContents(ctx, pCur->zPath);
      }
    }
  }
  return SQLITE_OK;
}

/*
** Return the rowid for the current row. In this implementation, the
** first row returned is assigned rowid value 1, and each subsequent
** row a value 1 more than that of the previous.
*/
static int fsdirRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
  fsdir_cursor *pCur = (fsdir_cursor*)cur;
  *pRowid = pCur->iRowid;
  return SQLITE_OK;
}

/*
** Return TRUE if the cursor has been moved off of the last
** row of output.
*/
static int fsdirEof(sqlite3_vtab_cursor *cur){
  fsdir_cursor *pCur = (fsdir_cursor*)cur;
  return (pCur->zPath==0);
}

/*
** xFilter callback.
*/
static int fsdirFilter(
  sqlite3_vtab_cursor *cur, 
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  const char *zDir = 0;
  fsdir_cursor *pCur = (fsdir_cursor*)cur;

  fsdirResetCursor(pCur);

  if( idxNum==0 ){
    fsdirSetErrmsg(pCur, "table function fsdir requires an argument");
    return SQLITE_ERROR;
  }

  assert( argc==idxNum && (argc==1 || argc==2) );
  zDir = (const char*)sqlite3_value_text(argv[0]);
  if( zDir==0 ){
    fsdirSetErrmsg(pCur, "table function fsdir requires a non-NULL argument");
    return SQLITE_ERROR;
  }
  if( argc==2 ){
    pCur->zBase = (const char*)sqlite3_value_text(argv[1]);
  }
  if( pCur->zBase ){
    pCur->nBase = (int)strlen(pCur->zBase)+1;
    pCur->zPath = sqlite3_mprintf("%s/%s", pCur->zBase, zDir);
  }else{
    pCur->zPath = sqlite3_mprintf("%s", zDir);
  }

  if( pCur->zPath==0 ){
    return SQLITE_NOMEM;
  }
  if( lstat(pCur->zPath, &pCur->sStat) ){
    fsdirSetErrmsg(pCur, "cannot stat file: %s", pCur->zPath);
    return SQLITE_ERROR;
  }

  return SQLITE_OK;
}

/*
** SQLite will invoke this method one or more times while planning a query
** that uses the generate_series virtual table.  This routine needs to create
** a query plan for each invocation and compute an estimated cost for that
** plan.
**
** In this implementation idxNum is used to represent the
** query plan.  idxStr is unused.
**
** The query plan is represented by bits in idxNum:
**
**  (1)  start = $value  -- constraint exists
**  (2)  stop = $value   -- constraint exists
**  (4)  step = $value   -- constraint exists
**  (8)  output in descending order
*/
static int fsdirBestIndex(
  sqlite3_vtab *tab,
  sqlite3_index_info *pIdxInfo
){
  int i;                 /* Loop over constraints */
  int idx4 = -1;
  int idx5 = -1;

  const struct sqlite3_index_constraint *pConstraint;
  pConstraint = pIdxInfo->aConstraint;
  for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){
    if( pConstraint->usable==0 ) continue;
    if( pConstraint->op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
    if( pConstraint->iColumn==4 ) idx4 = i;
    if( pConstraint->iColumn==5 ) idx5 = i;
  }

  if( idx4<0 ){
    pIdxInfo->idxNum = 0;
    pIdxInfo->estimatedCost = (double)(((sqlite3_int64)1) << 50);
  }else{
    pIdxInfo->aConstraintUsage[idx4].omit = 1;
    pIdxInfo->aConstraintUsage[idx4].argvIndex = 1;
    if( idx5>=0 ){
      pIdxInfo->aConstraintUsage[idx5].omit = 1;
      pIdxInfo->aConstraintUsage[idx5].argvIndex = 2;
      pIdxInfo->idxNum = 2;
      pIdxInfo->estimatedCost = 10.0;
    }else{
      pIdxInfo->idxNum = 1;
      pIdxInfo->estimatedCost = 100.0;
    }
  }

  return SQLITE_OK;
}

/*
** Register the "fsdir" virtual table.
*/
static int fsdirRegister(sqlite3 *db){
  static sqlite3_module fsdirModule = {
    0,                         /* iVersion */
    0,                         /* xCreate */
    fsdirConnect,              /* xConnect */
    fsdirBestIndex,            /* xBestIndex */
    fsdirDisconnect,           /* xDisconnect */
    0,                         /* xDestroy */
    fsdirOpen,                 /* xOpen - open a cursor */
    fsdirClose,                /* xClose - close a cursor */
    fsdirFilter,               /* xFilter - configure scan constraints */
    fsdirNext,                 /* xNext - advance a cursor */
    fsdirEof,                  /* xEof - check for end of scan */
    fsdirColumn,               /* xColumn - read data */
    fsdirRowid,                /* xRowid - read data */
    0,                         /* xUpdate */
    0,                         /* xBegin */
    0,                         /* xSync */
    0,                         /* xCommit */
    0,                         /* xRollback */
    0,                         /* xFindMethod */
    0,                         /* xRename */
  };

  int rc = sqlite3_create_module(db, "fsdir", &fsdirModule, 0);
  return rc;
}
#else         /* SQLITE_OMIT_VIRTUALTABLE */
# define fsdirRegister(x) SQLITE_OK
#endif

#ifdef _WIN32

#endif
int sqlite3_fileio_init(
  sqlite3 *db, 
  char **pzErrMsg, 
  const sqlite3_api_routines *pApi
){
  int rc = SQLITE_OK;
  SQLITE_EXTENSION_INIT2(pApi);
  (void)pzErrMsg;  /* Unused parameter */
  rc = sqlite3_create_function(db, "readfile", 1, SQLITE_UTF8, 0,
                               readfileFunc, 0, 0);
  if( rc==SQLITE_OK ){
    rc = sqlite3_create_function(db, "writefile", -1, SQLITE_UTF8, 0,
                                 writefileFunc, 0, 0);
  }
  if( rc==SQLITE_OK ){
    rc = fsdirRegister(db);
  }
  return rc;
}

/************************* End ../ext/misc/fileio.c ********************/
/************************* Begin ../ext/misc/completion.c ******************/
/*
** 2017-07-10

#ifndef SQLITE_OMIT_VIRTUALTABLE
  rc = sqlite3CompletionVtabInit(db);
#endif
  return rc;
}

/************************* End ../ext/misc/completion.c ********************/
/************************* Begin ../ext/misc/appendvfs.c ******************/
/*
** 2017-10-20
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file implements a VFS shim that allows an SQLite database to be
** appended onto the end of some other file, such as an executable.
**
** A special record must appear at the end of the file that identifies the
** file as an appended database and provides an offset to page 1.  For
** best performance page 1 should be located at a disk page boundary, though
** that is not required.
**
** When opening a database using this VFS, the connection might treat
** the file as an ordinary SQLite database, or it might treat is as a
** database appended onto some other file.  Here are the rules:
**
**  (1)  When opening a new empty file, that file is treated as an ordinary
**       database.
**
**  (2)  When opening a file that begins with the standard SQLite prefix
**       string "SQLite format 3", that file is treated as an ordinary
**       database.
**
**  (3)  When opening a file that ends with the appendvfs trailer string
**       "Start-Of-SQLite3-NNNNNNNN" that file is treated as an appended
**       database.
**
**  (4)  If none of the above apply and the SQLITE_OPEN_CREATE flag is
**       set, then a new database is appended to the already existing file.
**
**  (5)  Otherwise, SQLITE_CANTOPEN is returned.
**
** To avoid unnecessary complications with the PENDING_BYTE, the size of
** the file containing the database is limited to 1GB.  This VFS will refuse
** to read or write past the 1GB mark.  This restriction might be lifted in
** future versions.  For now, if you need a large database, then keep the
** database in a separate file.
**
** If the file being opened is not an appended database, then this shim is
** a pass-through into the default underlying VFS.
**/
SQLITE_EXTENSION_INIT1
#include <string.h>
#include <assert.h>

/* The append mark at the end of the database is:
**
**     Start-Of-SQLite3-NNNNNNNN
**     123456789 123456789 12345
**
** The NNNNNNNN represents a 64-bit big-endian unsigned integer which is
** the offset to page 1.
*/
#define APND_MARK_PREFIX     "Start-Of-SQLite3-"
#define APND_MARK_PREFIX_SZ  17
#define APND_MARK_SIZE       25

/*
** Maximum size of the combined prefix + database + append-mark.  This
** must be less than 0x40000000 to avoid locking issues on Windows.
*/
#define APND_MAX_SIZE  (65536*15259)

/*
** Forward declaration of objects used by this utility
*/
typedef struct sqlite3_vfs ApndVfs;
typedef struct ApndFile ApndFile;

/* Access to a lower-level VFS that (might) implement dynamic loading,
** access to randomness, etc.
*/
#define ORIGVFS(p)  ((sqlite3_vfs*)((p)->pAppData))
#define ORIGFILE(p) ((sqlite3_file*)(((ApndFile*)(p))+1))

/* An open file */
struct ApndFile {
  sqlite3_file base;              /* IO methods */
  sqlite3_int64 iPgOne;           /* File offset to page 1 */
  sqlite3_int64 iMark;            /* Start of the append-mark */
};

/*
** Methods for ApndFile
*/
static int apndClose(sqlite3_file*);
static int apndRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
static int apndWrite(sqlite3_file*,const void*,int iAmt, sqlite3_int64 iOfst);
static int apndTruncate(sqlite3_file*, sqlite3_int64 size);
static int apndSync(sqlite3_file*, int flags);
static int apndFileSize(sqlite3_file*, sqlite3_int64 *pSize);
static int apndLock(sqlite3_file*, int);
static int apndUnlock(sqlite3_file*, int);
static int apndCheckReservedLock(sqlite3_file*, int *pResOut);
static int apndFileControl(sqlite3_file*, int op, void *pArg);
static int apndSectorSize(sqlite3_file*);
static int apndDeviceCharacteristics(sqlite3_file*);
static int apndShmMap(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
static int apndShmLock(sqlite3_file*, int offset, int n, int flags);
static void apndShmBarrier(sqlite3_file*);
static int apndShmUnmap(sqlite3_file*, int deleteFlag);
static int apndFetch(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
static int apndUnfetch(sqlite3_file*, sqlite3_int64 iOfst, void *p);

/*
** Methods for ApndVfs
*/
static int apndOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
static int apndDelete(sqlite3_vfs*, const char *zName, int syncDir);
static int apndAccess(sqlite3_vfs*, const char *zName, int flags, int *);
static int apndFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
static void *apndDlOpen(sqlite3_vfs*, const char *zFilename);
static void apndDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
static void (*apndDlSym(sqlite3_vfs *pVfs, void *p, const char*zSym))(void);
static void apndDlClose(sqlite3_vfs*, void*);
static int apndRandomness(sqlite3_vfs*, int nByte, char *zOut);
static int apndSleep(sqlite3_vfs*, int microseconds);
static int apndCurrentTime(sqlite3_vfs*, double*);
static int apndGetLastError(sqlite3_vfs*, int, char *);
static int apndCurrentTimeInt64(sqlite3_vfs*, sqlite3_int64*);
static int apndSetSystemCall(sqlite3_vfs*, const char*,sqlite3_syscall_ptr);
static sqlite3_syscall_ptr apndGetSystemCall(sqlite3_vfs*, const char *z);
static const char *apndNextSystemCall(sqlite3_vfs*, const char *zName);

static sqlite3_vfs apnd_vfs = {
  3,                            /* iVersion (set when registered) */
  0,                            /* szOsFile (set when registered) */
  1024,                         /* mxPathname */
  0,                            /* pNext */
  "apndvfs",                    /* zName */
  0,                            /* pAppData (set when registered) */ 
  apndOpen,                     /* xOpen */
  apndDelete,                   /* xDelete */
  apndAccess,                   /* xAccess */
  apndFullPathname,             /* xFullPathname */
  apndDlOpen,                   /* xDlOpen */
  apndDlError,                  /* xDlError */
  apndDlSym,                    /* xDlSym */
  apndDlClose,                  /* xDlClose */
  apndRandomness,               /* xRandomness */
  apndSleep,                    /* xSleep */
  apndCurrentTime,              /* xCurrentTime */
  apndGetLastError,             /* xGetLastError */
  apndCurrentTimeInt64,         /* xCurrentTimeInt64 */
  apndSetSystemCall,            /* xSetSystemCall */
  apndGetSystemCall,            /* xGetSystemCall */
  apndNextSystemCall            /* xNextSystemCall */
};

static const sqlite3_io_methods apnd_io_methods = {
  3,                              /* iVersion */
  apndClose,                      /* xClose */
  apndRead,                       /* xRead */
  apndWrite,                      /* xWrite */
  apndTruncate,                   /* xTruncate */
  apndSync,                       /* xSync */
  apndFileSize,                   /* xFileSize */
  apndLock,                       /* xLock */
  apndUnlock,                     /* xUnlock */
  apndCheckReservedLock,          /* xCheckReservedLock */
  apndFileControl,                /* xFileControl */
  apndSectorSize,                 /* xSectorSize */
  apndDeviceCharacteristics,      /* xDeviceCharacteristics */
  apndShmMap,                     /* xShmMap */
  apndShmLock,                    /* xShmLock */
  apndShmBarrier,                 /* xShmBarrier */
  apndShmUnmap,                   /* xShmUnmap */
  apndFetch,                      /* xFetch */
  apndUnfetch                     /* xUnfetch */
};



/*
** Close an apnd-file.
*/
static int apndClose(sqlite3_file *pFile){
  pFile = ORIGFILE(pFile);
  return pFile->pMethods->xClose(pFile);
}

/*
** Read data from an apnd-file.
*/
static int apndRead(
  sqlite3_file *pFile, 
  void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){
  ApndFile *p = (ApndFile *)pFile;
  pFile = ORIGFILE(pFile);
  return pFile->pMethods->xRead(pFile, zBuf, iAmt, iOfst+p->iPgOne);
}

/*
** Add the append-mark onto the end of the file.
*/
static int apndWriteMark(ApndFile *p, sqlite3_file *pFile){
  int i;
  unsigned char a[APND_MARK_SIZE];
  memcpy(a, APND_MARK_PREFIX, APND_MARK_PREFIX_SZ);
  for(i=0; i<8; i++){
    a[APND_MARK_PREFIX_SZ+i] = (p->iPgOne >> (56 - i*8)) & 0xff;
  }
  return pFile->pMethods->xWrite(pFile, a, APND_MARK_SIZE, p->iMark);
}

/*
** Write data to an apnd-file.
*/
static int apndWrite(
  sqlite3_file *pFile,
  const void *zBuf,
  int iAmt,
  sqlite_int64 iOfst
){
  int rc;
  ApndFile *p = (ApndFile *)pFile;
  pFile = ORIGFILE(pFile);
  if( iOfst+iAmt>=APND_MAX_SIZE ) return SQLITE_FULL;
  rc = pFile->pMethods->xWrite(pFile, zBuf, iAmt, iOfst+p->iPgOne);
  if( rc==SQLITE_OK &&  iOfst + iAmt + p->iPgOne > p->iMark ){
    sqlite3_int64 sz = 0;
    rc = pFile->pMethods->xFileSize(pFile, &sz);
    if( rc==SQLITE_OK ){
      p->iMark = sz - APND_MARK_SIZE;
      if( iOfst + iAmt + p->iPgOne > p->iMark ){
        p->iMark = p->iPgOne + iOfst + iAmt;
        rc = apndWriteMark(p, pFile);
      }
    }
  }
  return rc;
}

/*
** Truncate an apnd-file.
*/
static int apndTruncate(sqlite3_file *pFile, sqlite_int64 size){
  int rc;
  ApndFile *p = (ApndFile *)pFile;
  pFile = ORIGFILE(pFile);
  rc = pFile->pMethods->xTruncate(pFile, size+p->iPgOne+APND_MARK_SIZE);
  if( rc==SQLITE_OK ){
    p->iMark = p->iPgOne+size;
    rc = apndWriteMark(p, pFile);
  }
  return rc;
}

/*
** Sync an apnd-file.
*/
static int apndSync(sqlite3_file *pFile, int flags){
  pFile = ORIGFILE(pFile);
  return pFile->pMethods->xSync(pFile, flags);
}

/*
** Return the current file-size of an apnd-file.
*/
static int apndFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
  ApndFile *p = (ApndFile *)pFile;
  int rc;
  pFile = ORIGFILE(p);
  rc = pFile->pMethods->xFileSize(pFile, pSize);
  if( rc==SQLITE_OK && p->iPgOne ){
    *pSize -= p->iPgOne + APND_MARK_SIZE;
  }
  return rc;
}

/*
** Lock an apnd-file.
*/
static int apndLock(sqlite3_file *pFile, int eLock){
  pFile = ORIGFILE(pFile);
  return pFile->pMethods->xLock(pFile, eLock);
}

/*
** Unlock an apnd-file.
*/
static int apndUnlock(sqlite3_file *pFile, int eLock){
  pFile = ORIGFILE(pFile);
  return pFile->pMethods->xUnlock(pFile, eLock);
}

/*
** Check if another file-handle holds a RESERVED lock on an apnd-file.
*/
static int apndCheckReservedLock(sqlite3_file *pFile, int *pResOut){
  pFile = ORIGFILE(pFile);
  return pFile->pMethods->xCheckReservedLock(pFile, pResOut);
}

/*
** File control method. For custom operations on an apnd-file.
*/
static int apndFileControl(sqlite3_file *pFile, int op, void *pArg){
  ApndFile *p = (ApndFile *)pFile;
  int rc;
  pFile = ORIGFILE(pFile);
  rc = pFile->pMethods->xFileControl(pFile, op, pArg);
  if( rc==SQLITE_OK && op==SQLITE_FCNTL_VFSNAME ){
    *(char**)pArg = sqlite3_mprintf("apnd(%lld)/%z", p->iPgOne, *(char**)pArg);
  }
  return rc;
}

/*
** Return the sector-size in bytes for an apnd-file.
*/
static int apndSectorSize(sqlite3_file *pFile){
  pFile = ORIGFILE(pFile);
  return pFile->pMethods->xSectorSize(pFile);
}

/*
** Return the device characteristic flags supported by an apnd-file.
*/
static int apndDeviceCharacteristics(sqlite3_file *pFile){
  pFile = ORIGFILE(pFile);
  return pFile->pMethods->xDeviceCharacteristics(pFile);
}

/* Create a shared memory file mapping */
static int apndShmMap(
  sqlite3_file *pFile,
  int iPg,
  int pgsz,
  int bExtend,
  void volatile **pp
){
  pFile = ORIGFILE(pFile);
  return pFile->pMethods->xShmMap(pFile,iPg,pgsz,bExtend,pp);
}

/* Perform locking on a shared-memory segment */
static int apndShmLock(sqlite3_file *pFile, int offset, int n, int flags){
  pFile = ORIGFILE(pFile);
  return pFile->pMethods->xShmLock(pFile,offset,n,flags);
}

/* Memory barrier operation on shared memory */
static void apndShmBarrier(sqlite3_file *pFile){
  pFile = ORIGFILE(pFile);
  pFile->pMethods->xShmBarrier(pFile);
}

/* Unmap a shared memory segment */
static int apndShmUnmap(sqlite3_file *pFile, int deleteFlag){
  pFile = ORIGFILE(pFile);
  return pFile->pMethods->xShmUnmap(pFile,deleteFlag);
}

/* Fetch a page of a memory-mapped file */
static int apndFetch(
  sqlite3_file *pFile,
  sqlite3_int64 iOfst,
  int iAmt,
  void **pp
){
  ApndFile *p = (ApndFile *)pFile;
  pFile = ORIGFILE(pFile);
  return pFile->pMethods->xFetch(pFile, iOfst+p->iPgOne, iAmt, pp);
}

/* Release a memory-mapped page */
static int apndUnfetch(sqlite3_file *pFile, sqlite3_int64 iOfst, void *pPage){
  ApndFile *p = (ApndFile *)pFile;
  pFile = ORIGFILE(pFile);
  return pFile->pMethods->xUnfetch(pFile, iOfst+p->iPgOne, pPage);
}

/*
** Check to see if the file is an ordinary SQLite database file.
*/
static int apndIsOrdinaryDatabaseFile(sqlite3_int64 sz, sqlite3_file *pFile){
  int rc;
  char zHdr[16];
  static const char aSqliteHdr[] = "SQLite format 3";
  if( sz<512 ) return 0;
  rc = pFile->pMethods->xRead(pFile, zHdr, sizeof(zHdr), 0);
  if( rc ) return 0;
  return memcmp(zHdr, aSqliteHdr, sizeof(zHdr))==0;
}

/*
** Try to read the append-mark off the end of a file.  Return the
** start of the appended database if the append-mark is present.  If
** there is no append-mark, return -1;
*/
static sqlite3_int64 apndReadMark(sqlite3_int64 sz, sqlite3_file *pFile){
  int rc, i;
  sqlite3_int64 iMark;
  unsigned char a[APND_MARK_SIZE];

  if( sz<=APND_MARK_SIZE ) return -1;
  rc = pFile->pMethods->xRead(pFile, a, APND_MARK_SIZE, sz-APND_MARK_SIZE);
  if( rc ) return -1;
  if( memcmp(a, APND_MARK_PREFIX, APND_MARK_PREFIX_SZ)!=0 ) return -1;
  iMark = ((sqlite3_int64)(a[APND_MARK_PREFIX_SZ]&0x7f))<<56;
  for(i=1; i<8; i++){    
    iMark += (sqlite3_int64)a[APND_MARK_PREFIX_SZ+i]<<(56-8*i);
  }
  return iMark;
}

/*
** Open an apnd file handle.
*/
static int apndOpen(
  sqlite3_vfs *pVfs,
  const char *zName,
  sqlite3_file *pFile,
  int flags,
  int *pOutFlags
){
  ApndFile *p;
  sqlite3_file *pSubFile;
  sqlite3_vfs *pSubVfs;
  int rc;
  sqlite3_int64 sz;
  pSubVfs = ORIGVFS(pVfs);
  if( (flags & SQLITE_OPEN_MAIN_DB)==0 ){
    return pSubVfs->xOpen(pSubVfs, zName, pFile, flags, pOutFlags);
  }
  p = (ApndFile*)pFile;
  memset(p, 0, sizeof(*p));
  pSubFile = ORIGFILE(pFile);
  p->base.pMethods = &apnd_io_methods;
  rc = pSubVfs->xOpen(pSubVfs, zName, pSubFile, flags, pOutFlags);
  if( rc ) goto apnd_open_done;
  rc = pSubFile->pMethods->xFileSize(pSubFile, &sz);
  if( rc ){
    pSubFile->pMethods->xClose(pSubFile);
    goto apnd_open_done;
  }
  if( apndIsOrdinaryDatabaseFile(sz, pSubFile) ){
    memmove(pFile, pSubFile, pSubVfs->szOsFile);
    return SQLITE_OK;
  }
  p->iMark = 0;
  p->iPgOne = apndReadMark(sz, pFile);
  if( p->iPgOne>0 ){
    return SQLITE_OK;
  }
  if( (flags & SQLITE_OPEN_CREATE)==0 ){
    pSubFile->pMethods->xClose(pSubFile);
    rc = SQLITE_CANTOPEN;
  }
  p->iPgOne = (sz+0xfff) & ~(sqlite3_int64)0xfff;
apnd_open_done:
  if( rc ) pFile->pMethods = 0;
  return rc;
}

/*
** All other VFS methods are pass-thrus.
*/
static int apndDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
  return ORIGVFS(pVfs)->xDelete(ORIGVFS(pVfs), zPath, dirSync);
}
static int apndAccess(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int flags, 
  int *pResOut
){
  return ORIGVFS(pVfs)->xAccess(ORIGVFS(pVfs), zPath, flags, pResOut);
}
static int apndFullPathname(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int nOut, 
  char *zOut
){
  return ORIGVFS(pVfs)->xFullPathname(ORIGVFS(pVfs),zPath,nOut,zOut);
}
static void *apndDlOpen(sqlite3_vfs *pVfs, const char *zPath){
  return ORIGVFS(pVfs)->xDlOpen(ORIGVFS(pVfs), zPath);
}
static void apndDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){
  ORIGVFS(pVfs)->xDlError(ORIGVFS(pVfs), nByte, zErrMsg);
}
static void (*apndDlSym(sqlite3_vfs *pVfs, void *p, const char *zSym))(void){
  return ORIGVFS(pVfs)->xDlSym(ORIGVFS(pVfs), p, zSym);
}
static void apndDlClose(sqlite3_vfs *pVfs, void *pHandle){
  ORIGVFS(pVfs)->xDlClose(ORIGVFS(pVfs), pHandle);
}
static int apndRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
  return ORIGVFS(pVfs)->xRandomness(ORIGVFS(pVfs), nByte, zBufOut);
}
static int apndSleep(sqlite3_vfs *pVfs, int nMicro){
  return ORIGVFS(pVfs)->xSleep(ORIGVFS(pVfs), nMicro);
}
static int apndCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
  return ORIGVFS(pVfs)->xCurrentTime(ORIGVFS(pVfs), pTimeOut);
}
static int apndGetLastError(sqlite3_vfs *pVfs, int a, char *b){
  return ORIGVFS(pVfs)->xGetLastError(ORIGVFS(pVfs), a, b);
}
static int apndCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *p){
  return ORIGVFS(pVfs)->xCurrentTimeInt64(ORIGVFS(pVfs), p);
}
static int apndSetSystemCall(
  sqlite3_vfs *pVfs,
  const char *zName,
  sqlite3_syscall_ptr pCall
){
  return ORIGVFS(pVfs)->xSetSystemCall(ORIGVFS(pVfs),zName,pCall);
}
static sqlite3_syscall_ptr apndGetSystemCall(
  sqlite3_vfs *pVfs,
  const char *zName
){
  return ORIGVFS(pVfs)->xGetSystemCall(ORIGVFS(pVfs),zName);
}
static const char *apndNextSystemCall(sqlite3_vfs *pVfs, const char *zName){
  return ORIGVFS(pVfs)->xNextSystemCall(ORIGVFS(pVfs), zName);
}

  
#ifdef _WIN32

#endif
/* 
** This routine is called when the extension is loaded.
** Register the new VFS.
*/
int sqlite3_appendvfs_init(
  sqlite3 *db, 
  char **pzErrMsg, 
  const sqlite3_api_routines *pApi
){
  int rc = SQLITE_OK;
  sqlite3_vfs *pOrig;
  SQLITE_EXTENSION_INIT2(pApi);
  pOrig = sqlite3_vfs_find(0);
  apnd_vfs.iVersion = pOrig->iVersion;
  apnd_vfs.pAppData = pOrig;
  apnd_vfs.szOsFile = pOrig->szOsFile + sizeof(ApndFile);
  rc = sqlite3_vfs_register(&apnd_vfs, 0);
#ifdef APPENDVFS_TEST
  if( rc==SQLITE_OK ){
    rc = sqlite3_auto_extension((void(*)(void))apndvfsRegister);
  }
#endif
  if( rc==SQLITE_OK ) rc = SQLITE_OK_LOAD_PERMANENTLY;
  return rc;
}

/************************* End ../ext/misc/appendvfs.c ********************/
#ifdef SQLITE_HAVE_ZLIB
/************************* Begin ../ext/misc/zipfile.c ******************/
/*
** 2017-12-26
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
*/
SQLITE_EXTENSION_INIT1
#include <stdio.h>
#include <string.h>
#include <assert.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#if !defined(_WIN32) && !defined(WIN32)
#  include <unistd.h>
#  include <dirent.h>
#  include <utime.h>
#else
#  include <io.h>
#endif
#include <time.h>
#include <errno.h>

#include <zlib.h>

#ifndef SQLITE_OMIT_VIRTUALTABLE

#ifndef SQLITE_AMALGAMATION
/* typedef sqlite3_int64 i64; */
/* typedef unsigned char u8; */
typedef unsigned short u16;
typedef unsigned long u32;
#define MIN(a,b) ((a)<(b) ? (a) : (b))
#endif

#define ZIPFILE_SCHEMA "CREATE TABLE y("                           \
  "name,      /* Name of file in zip archive */"                   \
  "mode,      /* POSIX mode for file */"                           \
  "mtime,     /* Last modification time in seconds since epoch */" \
  "sz,        /* Size of object */"                                \
  "data,      /* Data stored in zip file (possibly compressed) */" \
  "method,    /* Compression method (integer) */"                  \
  "f HIDDEN   /* Name of zip file */"                              \
");"

#define ZIPFILE_F_COLUMN_IDX 6    /* Index of column "f" in the above */
#define ZIPFILE_BUFFER_SIZE (64*1024)


/*
** Magic numbers used to read and write zip files.
**
** ZIPFILE_NEWENTRY_MADEBY:
**   Use this value for the "version-made-by" field in new zip file
**   entries. The upper byte indicates "unix", and the lower byte 
**   indicates that the zip file matches pkzip specification 3.0. 
**   This is what info-zip seems to do.
**
** ZIPFILE_NEWENTRY_REQUIRED:
**   Value for "version-required-to-extract" field of new entries.
**   Version 2.0 is required to support folders and deflate compression.
**
** ZIPFILE_NEWENTRY_FLAGS:
**   Value for "general-purpose-bit-flags" field of new entries. Bit
**   11 means "utf-8 filename and comment".
**
** ZIPFILE_SIGNATURE_CDS:
**   First 4 bytes of a valid CDS record.
**
** ZIPFILE_SIGNATURE_LFH:
**   First 4 bytes of a valid LFH record.
*/
#define ZIPFILE_EXTRA_TIMESTAMP   0x5455
#define ZIPFILE_NEWENTRY_MADEBY   ((3<<8) + 30)
#define ZIPFILE_NEWENTRY_REQUIRED 20
#define ZIPFILE_NEWENTRY_FLAGS    0x800
#define ZIPFILE_SIGNATURE_CDS     0x02014b50
#define ZIPFILE_SIGNATURE_LFH     0x04034b50
#define ZIPFILE_SIGNATURE_EOCD    0x06054b50
#define ZIPFILE_LFH_FIXED_SZ      30

/*
** Set the error message contained in context ctx to the results of
** vprintf(zFmt, ...).
*/
static void zipfileCtxErrorMsg(sqlite3_context *ctx, const char *zFmt, ...){
  char *zMsg = 0;
  va_list ap;
  va_start(ap, zFmt);
  zMsg = sqlite3_vmprintf(zFmt, ap);
  sqlite3_result_error(ctx, zMsg, -1);
  sqlite3_free(zMsg);
  va_end(ap);
}


/*
*** 4.3.16  End of central directory record:
***
***   end of central dir signature    4 bytes  (0x06054b50)
***   number of this disk             2 bytes
***   number of the disk with the
***   start of the central directory  2 bytes
***   total number of entries in the
***   central directory on this disk  2 bytes
***   total number of entries in
***   the central directory           2 bytes
***   size of the central directory   4 bytes
***   offset of start of central
***   directory with respect to
***   the starting disk number        4 bytes
***   .ZIP file comment length        2 bytes
***   .ZIP file comment       (variable size)
*/
typedef struct ZipfileEOCD ZipfileEOCD;
struct ZipfileEOCD {
  u16 iDisk;
  u16 iFirstDisk;
  u16 nEntry;
  u16 nEntryTotal;
  u32 nSize;
  u32 iOffset;
};

/*
*** 4.3.12  Central directory structure:
***
*** ...
***
***   central file header signature   4 bytes  (0x02014b50)
***   version made by                 2 bytes
***   version needed to extract       2 bytes
***   general purpose bit flag        2 bytes
***   compression method              2 bytes
***   last mod file time              2 bytes
***   last mod file date              2 bytes
***   crc-32                          4 bytes
***   compressed size                 4 bytes
***   uncompressed size               4 bytes
***   file name length                2 bytes
***   extra field length              2 bytes
***   file comment length             2 bytes
***   disk number start               2 bytes
***   internal file attributes        2 bytes
***   external file attributes        4 bytes
***   relative offset of local header 4 bytes
*/
typedef struct ZipfileCDS ZipfileCDS;
struct ZipfileCDS {
  u16 iVersionMadeBy;
  u16 iVersionExtract;
  u16 flags;
  u16 iCompression;
  u16 mTime;
  u16 mDate;
  u32 crc32;
  u32 szCompressed;
  u32 szUncompressed;
  u16 nFile;
  u16 nExtra;
  u16 nComment;
  u16 iDiskStart;
  u16 iInternalAttr;
  u32 iExternalAttr;
  u32 iOffset;
  char *zFile;                    /* Filename (sqlite3_malloc()) */
};

/*
*** 4.3.7  Local file header:
***
***   local file header signature     4 bytes  (0x04034b50)
***   version needed to extract       2 bytes
***   general purpose bit flag        2 bytes
***   compression method              2 bytes
***   last mod file time              2 bytes
***   last mod file date              2 bytes
***   crc-32                          4 bytes
***   compressed size                 4 bytes
***   uncompressed size               4 bytes
***   file name length                2 bytes
***   extra field length              2 bytes
***   
*/
typedef struct ZipfileLFH ZipfileLFH;
struct ZipfileLFH {
  u16 iVersionExtract;
  u16 flags;
  u16 iCompression;
  u16 mTime;
  u16 mDate;
  u32 crc32;
  u32 szCompressed;
  u32 szUncompressed;
  u16 nFile;
  u16 nExtra;
};

typedef struct ZipfileEntry ZipfileEntry;
struct ZipfileEntry {
  char *zPath;               /* Path of zipfile entry */
  i64 iRowid;                /* Rowid for this value if queried */
  u8 *aCdsEntry;             /* Buffer containing entire CDS entry */
  int nCdsEntry;             /* Size of buffer aCdsEntry[] in bytes */
  int bDeleted;              /* True if entry has been deleted */
  ZipfileEntry *pNext;       /* Next element in in-memory CDS */
};

/* 
** Cursor type for recursively iterating through a directory structure.
*/
typedef struct ZipfileCsr ZipfileCsr;
struct ZipfileCsr {
  sqlite3_vtab_cursor base;  /* Base class - must be first */
  int bEof;                  /* True when at EOF */

  /* Used outside of write transactions */
  FILE *pFile;               /* Zip file */
  i64 iNextOff;              /* Offset of next record in central directory */
  ZipfileEOCD eocd;          /* Parse of central directory record */

  /* Used inside write transactions */
  ZipfileEntry *pCurrent;

  ZipfileCDS cds;            /* Central Directory Structure */
  ZipfileLFH lfh;            /* Local File Header for current entry */
  i64 iDataOff;              /* Offset in zipfile to data */
  u32 mTime;                 /* Extended mtime value */
  int flags;                 /* Flags byte (see below for bits) */
  ZipfileCsr *pCsrNext;      /* Next cursor on same virtual table */
};

/*
** Values for ZipfileCsr.flags.
*/
#define ZIPFILE_MTIME_VALID 0x0001

typedef struct ZipfileTab ZipfileTab;
struct ZipfileTab {
  sqlite3_vtab base;         /* Base class - must be first */
  char *zFile;               /* Zip file this table accesses (may be NULL) */
  u8 *aBuffer;               /* Temporary buffer used for various tasks */

  /* The following are used by write transactions only */
  ZipfileCsr *pCsrList;      /* List of cursors */
  ZipfileEntry *pFirstEntry; /* Linked list of all files (if pWriteFd!=0) */
  ZipfileEntry *pLastEntry;  /* Last element in pFirstEntry list */
  FILE *pWriteFd;            /* File handle open on zip archive */
  i64 szCurrent;             /* Current size of zip archive */
  i64 szOrig;                /* Size of archive at start of transaction */
};

static void zipfileDequote(char *zIn){
  char q = zIn[0];
  if( q=='"' || q=='\'' || q=='`' || q=='[' ){
    char c;
    int iIn = 1;
    int iOut = 0;
    if( q=='[' ) q = ']';
    while( (c = zIn[iIn++]) ){
      if( c==q ){
        if( zIn[iIn++]!=q ) break;
      }
      zIn[iOut++] = c;
    }
    zIn[iOut] = '\0';
  }
}

/*
** Construct a new ZipfileTab virtual table object.
** 
**   argv[0]   -> module name  ("zipfile")
**   argv[1]   -> database name
**   argv[2]   -> table name
**   argv[...] -> "column name" and other module argument fields.
*/
static int zipfileConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  int nByte = sizeof(ZipfileTab) + ZIPFILE_BUFFER_SIZE;
  int nFile = 0;
  const char *zFile = 0;
  ZipfileTab *pNew = 0;
  int rc;

  if( argc>3 ){
    zFile = argv[3];
    nFile = (int)strlen(zFile)+1;
  }

  rc = sqlite3_declare_vtab(db, ZIPFILE_SCHEMA);
  if( rc==SQLITE_OK ){
    pNew = (ZipfileTab*)sqlite3_malloc(nByte+nFile);
    if( pNew==0 ) return SQLITE_NOMEM;
    memset(pNew, 0, nByte+nFile);
    pNew->aBuffer = (u8*)&pNew[1];
    if( zFile ){
      pNew->zFile = (char*)&pNew->aBuffer[ZIPFILE_BUFFER_SIZE];
      memcpy(pNew->zFile, zFile, nFile);
      zipfileDequote(pNew->zFile);
    }
  }
  *ppVtab = (sqlite3_vtab*)pNew;
  return rc;
}

/*
** This method is the destructor for zipfile vtab objects.
*/
static int zipfileDisconnect(sqlite3_vtab *pVtab){
  sqlite3_free(pVtab);
  return SQLITE_OK;
}

/*
** Constructor for a new ZipfileCsr object.
*/
static int zipfileOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCsr){
  ZipfileCsr *pCsr;
  pCsr = sqlite3_malloc(sizeof(*pCsr));
  *ppCsr = (sqlite3_vtab_cursor*)pCsr;
  if( pCsr==0 ){
    return SQLITE_NOMEM;
  }
  memset(pCsr, 0, sizeof(*pCsr));
  return SQLITE_OK;
}

/*
** Reset a cursor back to the state it was in when first returned
** by zipfileOpen().
*/
static void zipfileResetCursor(ZipfileCsr *pCsr){
  ZipfileTab *pTab = (ZipfileTab*)(pCsr->base.pVtab);
  ZipfileCsr **pp;

  /* Remove this cursor from the ZipfileTab.pCsrList list. */
  for(pp=&pTab->pCsrList; *pp; pp=&((*pp)->pCsrNext)){
    if( *pp==pCsr ) *pp = pCsr->pCsrNext;
  }

  sqlite3_free(pCsr->cds.zFile);
  pCsr->cds.zFile = 0;
  pCsr->bEof = 0;
  if( pCsr->pFile ){
    fclose(pCsr->pFile);
    pCsr->pFile = 0;
  }
}

/*
** Destructor for an ZipfileCsr.
*/
static int zipfileClose(sqlite3_vtab_cursor *cur){
  ZipfileCsr *pCsr = (ZipfileCsr*)cur;
  zipfileResetCursor(pCsr);
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

/*
** Set the error message for the virtual table associated with cursor
** pCsr to the results of vprintf(zFmt, ...).
*/
static void zipfileSetErrmsg(ZipfileCsr *pCsr, const char *zFmt, ...){
  va_list ap;
  va_start(ap, zFmt);
  pCsr->base.pVtab->zErrMsg = sqlite3_vmprintf(zFmt, ap);
  va_end(ap);
}

static int zipfileReadData(
  FILE *pFile,                    /* Read from this file */
  u8 *aRead,                      /* Read into this buffer */
  int nRead,                      /* Number of bytes to read */
  i64 iOff,                       /* Offset to read from */
  char **pzErrmsg                 /* OUT: Error message (from sqlite3_malloc) */
){
  size_t n;
  fseek(pFile, (long)iOff, SEEK_SET);
  n = fread(aRead, 1, nRead, pFile);
  if( (int)n!=nRead ){
    *pzErrmsg = sqlite3_mprintf("error in fread()");
    return SQLITE_ERROR;
  }
  return SQLITE_OK;
}

static int zipfileAppendData(
  ZipfileTab *pTab,
  const u8 *aWrite,
  int nWrite
){
  size_t n;
  fseek(pTab->pWriteFd, (long)pTab->szCurrent, SEEK_SET);
  n = fwrite(aWrite, 1, nWrite, pTab->pWriteFd);
  if( (int)n!=nWrite ){
    pTab->base.zErrMsg = sqlite3_mprintf("error in fwrite()");
    return SQLITE_ERROR;
  }
  pTab->szCurrent += nWrite;
  return SQLITE_OK;
}

static u16 zipfileGetU16(const u8 *aBuf){
  return (aBuf[1] << 8) + aBuf[0];
}
static u32 zipfileGetU32(const u8 *aBuf){
  return ((u32)(aBuf[3]) << 24)
       + ((u32)(aBuf[2]) << 16)
       + ((u32)(aBuf[1]) <<  8)
       + ((u32)(aBuf[0]) <<  0);
}

static void zipfilePutU16(u8 *aBuf, u16 val){
  aBuf[0] = val & 0xFF;
  aBuf[1] = (val>>8) & 0xFF;
}
static void zipfilePutU32(u8 *aBuf, u32 val){
  aBuf[0] = val & 0xFF;
  aBuf[1] = (val>>8) & 0xFF;
  aBuf[2] = (val>>16) & 0xFF;
  aBuf[3] = (val>>24) & 0xFF;
}

#define zipfileRead32(aBuf) ( aBuf+=4, zipfileGetU32(aBuf-4) )
#define zipfileRead16(aBuf) ( aBuf+=2, zipfileGetU16(aBuf-2) )

#define zipfileWrite32(aBuf,val) { zipfilePutU32(aBuf,val); aBuf+=4; }
#define zipfileWrite16(aBuf,val) { zipfilePutU16(aBuf,val); aBuf+=2; }

static u8* zipfileCsrBuffer(ZipfileCsr *pCsr){
  return ((ZipfileTab*)(pCsr->base.pVtab))->aBuffer;
}

/*
** Magic numbers used to read CDS records.
*/
#define ZIPFILE_CDS_FIXED_SZ  46
#define ZIPFILE_CDS_NFILE_OFF 28

static int zipfileReadCDS(ZipfileCsr *pCsr){
  char **pzErr = &pCsr->base.pVtab->zErrMsg;
  u8 *aRead;
  int rc = SQLITE_OK;

  sqlite3_free(pCsr->cds.zFile);
  pCsr->cds.zFile = 0;

  if( pCsr->pCurrent==0 ){
    aRead = zipfileCsrBuffer(pCsr);
    rc = zipfileReadData(
        pCsr->pFile, aRead, ZIPFILE_CDS_FIXED_SZ, pCsr->iNextOff, pzErr
    );
  }else{
    aRead = pCsr->pCurrent->aCdsEntry;
  }

  if( rc==SQLITE_OK ){
    u32 sig = zipfileRead32(aRead);
    if( sig!=ZIPFILE_SIGNATURE_CDS ){
      assert( pCsr->pCurrent==0 );
      zipfileSetErrmsg(pCsr,"failed to read CDS at offset %lld",pCsr->iNextOff);
      rc = SQLITE_ERROR;
    }else{
      int nRead;
      pCsr->cds.iVersionMadeBy = zipfileRead16(aRead);
      pCsr->cds.iVersionExtract = zipfileRead16(aRead);
      pCsr->cds.flags = zipfileRead16(aRead);
      pCsr->cds.iCompression = zipfileRead16(aRead);
      pCsr->cds.mTime = zipfileRead16(aRead);
      pCsr->cds.mDate = zipfileRead16(aRead);
      pCsr->cds.crc32 = zipfileRead32(aRead);
      pCsr->cds.szCompressed = zipfileRead32(aRead);
      pCsr->cds.szUncompressed = zipfileRead32(aRead);
      assert( pCsr->pCurrent 
           || aRead==zipfileCsrBuffer(pCsr)+ZIPFILE_CDS_NFILE_OFF 
      );
      pCsr->cds.nFile = zipfileRead16(aRead);
      pCsr->cds.nExtra = zipfileRead16(aRead);
      pCsr->cds.nComment = zipfileRead16(aRead);
      pCsr->cds.iDiskStart = zipfileRead16(aRead);
      pCsr->cds.iInternalAttr = zipfileRead16(aRead);
      pCsr->cds.iExternalAttr = zipfileRead32(aRead);
      pCsr->cds.iOffset = zipfileRead32(aRead);
      assert( pCsr->pCurrent 
           || aRead==zipfileCsrBuffer(pCsr)+ZIPFILE_CDS_FIXED_SZ
      );

      if( pCsr->pCurrent==0 ){
        nRead = pCsr->cds.nFile + pCsr->cds.nExtra;
        aRead = zipfileCsrBuffer(pCsr);
        pCsr->iNextOff += ZIPFILE_CDS_FIXED_SZ;
        rc = zipfileReadData(pCsr->pFile, aRead, nRead, pCsr->iNextOff, pzErr);
      }

      if( rc==SQLITE_OK ){
        pCsr->cds.zFile = sqlite3_mprintf("%.*s", (int)pCsr->cds.nFile, aRead);
        pCsr->iNextOff += pCsr->cds.nFile;
        pCsr->iNextOff += pCsr->cds.nExtra;
        pCsr->iNextOff += pCsr->cds.nComment;
      }

      /* Scan the cds.nExtra bytes of "extra" fields for any that can
      ** be interpreted. The general format of an extra field is:
      **
      **   Header ID    2 bytes
      **   Data Size    2 bytes
      **   Data         N bytes
      **
      */
      if( rc==SQLITE_OK ){
        u8 *p = &aRead[pCsr->cds.nFile];
        u8 *pEnd = &p[pCsr->cds.nExtra];

        while( p<pEnd ){
          u16 id = zipfileRead16(p);
          u16 nByte = zipfileRead16(p);

          switch( id ){
            case ZIPFILE_EXTRA_TIMESTAMP: {
              u8 b = p[0];
              if( b & 0x01 ){     /* 0x01 -> modtime is present */
                pCsr->mTime = zipfileGetU32(&p[1]);
                pCsr->flags |= ZIPFILE_MTIME_VALID;
              }
              break;
            }
          }

          p += nByte;
        }
      }
    }
  }

  return rc;
}

static FILE *zipfileGetFd(ZipfileCsr *pCsr){
  if( pCsr->pFile ) return pCsr->pFile;
  return ((ZipfileTab*)(pCsr->base.pVtab))->pWriteFd;
}

static int zipfileReadLFH(ZipfileCsr *pCsr){
  FILE *pFile = zipfileGetFd(pCsr);
  char **pzErr = &pCsr->base.pVtab->zErrMsg;
  static const int szFix = ZIPFILE_LFH_FIXED_SZ;
  u8 *aRead = zipfileCsrBuffer(pCsr);
  int rc;

  rc = zipfileReadData(pFile, aRead, szFix, pCsr->cds.iOffset, pzErr);
  if( rc==SQLITE_OK ){
    u32 sig = zipfileRead32(aRead);
    if( sig!=ZIPFILE_SIGNATURE_LFH ){
      zipfileSetErrmsg(pCsr, "failed to read LFH at offset %d", 
          (int)pCsr->cds.iOffset
      );
      rc = SQLITE_ERROR;
    }else{
      pCsr->lfh.iVersionExtract = zipfileRead16(aRead);
      pCsr->lfh.flags = zipfileRead16(aRead);
      pCsr->lfh.iCompression = zipfileRead16(aRead);
      pCsr->lfh.mTime = zipfileRead16(aRead);
      pCsr->lfh.mDate = zipfileRead16(aRead);
      pCsr->lfh.crc32 = zipfileRead32(aRead);
      pCsr->lfh.szCompressed = zipfileRead32(aRead);
      pCsr->lfh.szUncompressed = zipfileRead32(aRead);
      pCsr->lfh.nFile = zipfileRead16(aRead);
      pCsr->lfh.nExtra = zipfileRead16(aRead);
      assert( aRead==zipfileCsrBuffer(pCsr)+szFix );
      pCsr->iDataOff = pCsr->cds.iOffset+szFix+pCsr->lfh.nFile+pCsr->lfh.nExtra;
    }
  }

  return rc;
}


/*
** Advance an ZipfileCsr to its next row of output.
*/
static int zipfileNext(sqlite3_vtab_cursor *cur){
  ZipfileCsr *pCsr = (ZipfileCsr*)cur;
  int rc = SQLITE_OK;
  pCsr->flags = 0;

  if( pCsr->pCurrent==0 ){
    i64 iEof = pCsr->eocd.iOffset + pCsr->eocd.nSize;
    if( pCsr->iNextOff>=iEof ){
      pCsr->bEof = 1;
    }
  }else{
    assert( pCsr->pFile==0 );
    do {
      pCsr->pCurrent = pCsr->pCurrent->pNext;
    }while( pCsr->pCurrent && pCsr->pCurrent->bDeleted );
    if( pCsr->pCurrent==0 ){
      pCsr->bEof = 1;
    }
  }

  if( pCsr->bEof==0 ){
    rc = zipfileReadCDS(pCsr);
    if( rc==SQLITE_OK ){
      rc = zipfileReadLFH(pCsr);
    }
  }

  return rc;
}

/*
** "Standard" MS-DOS time format:
**
**   File modification time:
**     Bits 00-04: seconds divided by 2
**     Bits 05-10: minute
**     Bits 11-15: hour
**   File modification date:
**     Bits 00-04: day
**     Bits 05-08: month (1-12)
**     Bits 09-15: years from 1980 
*/
static time_t zipfileMtime(ZipfileCsr *pCsr){
  struct tm t;
  memset(&t, 0, sizeof(t));
  t.tm_sec = (pCsr->cds.mTime & 0x1F)*2;
  t.tm_min = (pCsr->cds.mTime >> 5) & 0x2F;
  t.tm_hour = (pCsr->cds.mTime >> 11) & 0x1F;

  t.tm_mday = (pCsr->cds.mDate & 0x1F);
  t.tm_mon = ((pCsr->cds.mDate >> 5) & 0x0F) - 1;
  t.tm_year = 80 + ((pCsr->cds.mDate >> 9) & 0x7F);

  return mktime(&t);
}

static void zipfileMtimeToDos(ZipfileCDS *pCds, u32 mTime){
  time_t t = (time_t)mTime;
  struct tm res;

#if !defined(_WIN32) && !defined(WIN32)
  localtime_r(&t, &res);
#else
  memcpy(&res, localtime(&t), sizeof(struct tm));
#endif

  pCds->mTime = (u16)(
    (res.tm_sec / 2) + 
    (res.tm_min << 5) +
    (res.tm_hour << 11));

  pCds->mDate = (u16)(
    (res.tm_mday-1) +
    ((res.tm_mon+1) << 5) +
    ((res.tm_year-80) << 9));
}

/*
** Return values of columns for the row at which the series_cursor
** is currently pointing.
*/
static int zipfileColumn(
  sqlite3_vtab_cursor *cur,   /* The cursor */
  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
  int i                       /* Which column to return */
){
  ZipfileCsr *pCsr = (ZipfileCsr*)cur;
  int rc = SQLITE_OK;
  switch( i ){
    case 0:   /* name */
      sqlite3_result_text(ctx, pCsr->cds.zFile, -1, SQLITE_TRANSIENT);
      break;
    case 1:   /* mode */
      /* TODO: Whether or not the following is correct surely depends on
      ** the platform on which the archive was created.  */
      sqlite3_result_int(ctx, pCsr->cds.iExternalAttr >> 16);
      break;
    case 2: { /* mtime */
      if( pCsr->flags & ZIPFILE_MTIME_VALID ){
        sqlite3_result_int64(ctx, pCsr->mTime);
      }else{
        sqlite3_result_int64(ctx, zipfileMtime(pCsr));
      }
      break;
    }
    case 3: { /* sz */
      sqlite3_result_int64(ctx, pCsr->cds.szUncompressed);
      break;
    }
    case 4: { /* data */
      int sz = pCsr->cds.szCompressed;
      if( sz>0 ){
        u8 *aBuf = sqlite3_malloc(sz);
        if( aBuf==0 ){
          rc = SQLITE_NOMEM;
        }else{
          FILE *pFile = zipfileGetFd(pCsr);
          rc = zipfileReadData(pFile, aBuf, sz, pCsr->iDataOff,
              &pCsr->base.pVtab->zErrMsg
          );
        }
        if( rc==SQLITE_OK ){
          sqlite3_result_blob(ctx, aBuf, sz, SQLITE_TRANSIENT);
          sqlite3_free(aBuf);
        }
      }
      break;
    }
    case 5:   /* method */
      sqlite3_result_int(ctx, pCsr->cds.iCompression);
      break;
  }

  return SQLITE_OK;
}

/*
** Return the rowid for the current row.
*/
static int zipfileRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
  ZipfileCsr *pCsr = (ZipfileCsr*)cur;
  if( pCsr->pCurrent ){
    *pRowid = pCsr->pCurrent->iRowid;
  }else{
    *pRowid = pCsr->cds.iOffset;
  }
  return SQLITE_OK;
}

/*
** Return TRUE if the cursor has been moved off of the last
** row of output.
*/
static int zipfileEof(sqlite3_vtab_cursor *cur){
  ZipfileCsr *pCsr = (ZipfileCsr*)cur;
  return pCsr->bEof;
}

/*
*/
static int zipfileReadEOCD(
  ZipfileTab *pTab,               /* Return errors here */
  FILE *pFile,                    /* Read from this file */
  ZipfileEOCD *pEOCD              /* Object to populate */
){
  u8 *aRead = pTab->aBuffer;      /* Temporary buffer */
  i64 szFile;                     /* Total size of file in bytes */
  int nRead;                      /* Bytes to read from file */
  i64 iOff;                       /* Offset to read from */
  int rc;

  fseek(pFile, 0, SEEK_END);
  szFile = (i64)ftell(pFile);
  if( szFile==0 ){
    return SQLITE_EMPTY;
  }
  nRead = (int)(MIN(szFile, ZIPFILE_BUFFER_SIZE));
  iOff = szFile - nRead;

  rc = zipfileReadData(pFile, aRead, nRead, iOff, &pTab->base.zErrMsg);
  if( rc==SQLITE_OK ){
    int i;

    /* Scan backwards looking for the signature bytes */
    for(i=nRead-20; i>=0; i--){
      if( aRead[i]==0x50 && aRead[i+1]==0x4b 
       && aRead[i+2]==0x05 && aRead[i+3]==0x06 
      ){
        break;
      }
    }
    if( i<0 ){
      pTab->base.zErrMsg = sqlite3_mprintf(
          "cannot find end of central directory record"
      );
      return SQLITE_ERROR;
    }

    aRead += i+4;
    pEOCD->iDisk = zipfileRead16(aRead);
    pEOCD->iFirstDisk = zipfileRead16(aRead);
    pEOCD->nEntry = zipfileRead16(aRead);
    pEOCD->nEntryTotal = zipfileRead16(aRead);
    pEOCD->nSize = zipfileRead32(aRead);
    pEOCD->iOffset = zipfileRead32(aRead);

#if 0
    printf("iDisk=%d  iFirstDisk=%d  nEntry=%d  "
           "nEntryTotal=%d  nSize=%d  iOffset=%d", 
           (int)pEOCD->iDisk, (int)pEOCD->iFirstDisk, (int)pEOCD->nEntry,
           (int)pEOCD->nEntryTotal, (int)pEOCD->nSize, (int)pEOCD->iOffset
    );
#endif
  }

  return SQLITE_OK;
}

/*
** xFilter callback.
*/
static int zipfileFilter(
  sqlite3_vtab_cursor *cur, 
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  ZipfileTab *pTab = (ZipfileTab*)cur->pVtab;
  ZipfileCsr *pCsr = (ZipfileCsr*)cur;
  const char *zFile;              /* Zip file to scan */
  int rc = SQLITE_OK;             /* Return Code */

  zipfileResetCursor(pCsr);

  if( pTab->zFile ){
    zFile = pTab->zFile;
  }else if( idxNum==0 ){
    /* Error. This is an eponymous virtual table and the user has not 
    ** supplied a file name. */
    zipfileSetErrmsg(pCsr, "table function zipfile() requires an argument");
    return SQLITE_ERROR;
  }else{
    zFile = (const char*)sqlite3_value_text(argv[0]);
  }

  if( pTab->pWriteFd==0 ){
    pCsr->pFile = fopen(zFile, "rb");
    if( pCsr->pFile==0 ){
      zipfileSetErrmsg(pCsr, "cannot open file: %s", zFile);
      rc = SQLITE_ERROR;
    }else{
      rc = zipfileReadEOCD(pTab, pCsr->pFile, &pCsr->eocd);
      if( rc==SQLITE_OK ){
        pCsr->iNextOff = pCsr->eocd.iOffset;
        rc = zipfileNext(cur);
      }else if( rc==SQLITE_EMPTY ){
        rc = SQLITE_OK;
        pCsr->bEof = 1;
      }
    }
  }else{
    ZipfileEntry e;
    memset(&e, 0, sizeof(e));
    e.pNext = pTab->pFirstEntry;
    pCsr->pCurrent = &e;
    rc = zipfileNext(cur);
    assert( pCsr->pCurrent!=&e );
  }

  return rc;
}

/*
** xBestIndex callback.
*/
static int zipfileBestIndex(
  sqlite3_vtab *tab,
  sqlite3_index_info *pIdxInfo
){
  int i;

  for(i=0; i<pIdxInfo->nConstraint; i++){
    const struct sqlite3_index_constraint *pCons = &pIdxInfo->aConstraint[i];
    if( pCons->usable==0 ) continue;
    if( pCons->op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
    if( pCons->iColumn!=ZIPFILE_F_COLUMN_IDX ) continue;
    break;
  }

  if( i<pIdxInfo->nConstraint ){
    pIdxInfo->aConstraintUsage[i].argvIndex = 1;
    pIdxInfo->aConstraintUsage[i].omit = 1;
    pIdxInfo->estimatedCost = 1000.0;
    pIdxInfo->idxNum = 1;
  }else{
    pIdxInfo->estimatedCost = (double)(((sqlite3_int64)1) << 50);
    pIdxInfo->idxNum = 0;
  }

  return SQLITE_OK;
}

/*
** Add object pNew to the end of the linked list that begins at
** ZipfileTab.pFirstEntry and ends with pLastEntry.
*/
static void zipfileAddEntry(ZipfileTab *pTab, ZipfileEntry *pNew){
  assert( (pTab->pFirstEntry==0)==(pTab->pLastEntry==0) );
  assert( pNew->pNext==0 );
  if( pTab->pFirstEntry==0 ){
    pNew->iRowid = 1;
    pTab->pFirstEntry = pTab->pLastEntry = pNew;
  }else{
    assert( pTab->pLastEntry->pNext==0 );
    pNew->iRowid = pTab->pLastEntry->iRowid+1;
    pTab->pLastEntry->pNext = pNew;
    pTab->pLastEntry = pNew;
  }
}

static int zipfileLoadDirectory(ZipfileTab *pTab){
  ZipfileEOCD eocd;
  int rc;

  rc = zipfileReadEOCD(pTab, pTab->pWriteFd, &eocd);
  if( rc==SQLITE_OK ){
    int i;
    int iOff = 0;
    u8 *aBuf = sqlite3_malloc(eocd.nSize);
    if( aBuf==0 ){
      rc = SQLITE_NOMEM;
    }else{
      rc = zipfileReadData(
          pTab->pWriteFd, aBuf, eocd.nSize, eocd.iOffset, &pTab->base.zErrMsg
      );
    }

    for(i=0; rc==SQLITE_OK && i<eocd.nEntry; i++){
      u16 nFile;
      u16 nExtra;
      u16 nComment;
      ZipfileEntry *pNew;
      u8 *aRec = &aBuf[iOff];

      nFile = zipfileGetU16(&aRec[ZIPFILE_CDS_NFILE_OFF]);
      nExtra = zipfileGetU16(&aRec[ZIPFILE_CDS_NFILE_OFF+2]);
      nComment = zipfileGetU16(&aRec[ZIPFILE_CDS_NFILE_OFF+4]);

      pNew = sqlite3_malloc(
          sizeof(ZipfileEntry) 
        + nFile+1 
        + ZIPFILE_CDS_FIXED_SZ+nFile+nExtra+nComment
      );
      if( pNew==0 ){
        rc = SQLITE_NOMEM;
      }else{
        memset(pNew, 0, sizeof(ZipfileEntry));
        pNew->zPath = (char*)&pNew[1];
        memcpy(pNew->zPath, &aBuf[ZIPFILE_CDS_FIXED_SZ], nFile);
        pNew->zPath[nFile] = '\0';
        pNew->aCdsEntry = (u8*)&pNew->zPath[nFile+1];
        pNew->nCdsEntry = ZIPFILE_CDS_FIXED_SZ+nFile+nExtra+nComment;
        memcpy(pNew->aCdsEntry, aRec, pNew->nCdsEntry);
        zipfileAddEntry(pTab, pNew);
      }

      iOff += ZIPFILE_CDS_FIXED_SZ+nFile+nExtra+nComment;
    }

    sqlite3_free(aBuf);
  }else if( rc==SQLITE_EMPTY ){
    rc = SQLITE_OK;
  }

  return rc;
}

static ZipfileEntry *zipfileNewEntry(
  ZipfileCDS *pCds,               /* Values for fixed size part of CDS */
  const char *zPath,              /* Path for new entry */
  int nPath,                      /* strlen(zPath) */
  u32 mTime                       /* Modification time (or 0) */
){
  u8 *aWrite;
  ZipfileEntry *pNew;
  pCds->nFile = (u16)nPath;
  pCds->nExtra = mTime ? 9 : 0;
  pNew = (ZipfileEntry*)sqlite3_malloc(
    sizeof(ZipfileEntry) + 
    nPath+1 + 
    ZIPFILE_CDS_FIXED_SZ + nPath + pCds->nExtra
  );

  if( pNew ){
    memset(pNew, 0, sizeof(ZipfileEntry));
    pNew->zPath = (char*)&pNew[1];
    pNew->aCdsEntry = (u8*)&pNew->zPath[nPath+1];
    pNew->nCdsEntry = ZIPFILE_CDS_FIXED_SZ + nPath + pCds->nExtra;
    memcpy(pNew->zPath, zPath, nPath+1);

    aWrite = pNew->aCdsEntry;
    zipfileWrite32(aWrite, ZIPFILE_SIGNATURE_CDS);
    zipfileWrite16(aWrite, pCds->iVersionMadeBy);
    zipfileWrite16(aWrite, pCds->iVersionExtract);
    zipfileWrite16(aWrite, pCds->flags);
    zipfileWrite16(aWrite, pCds->iCompression);
    zipfileWrite16(aWrite, pCds->mTime);
    zipfileWrite16(aWrite, pCds->mDate);
    zipfileWrite32(aWrite, pCds->crc32);
    zipfileWrite32(aWrite, pCds->szCompressed);
    zipfileWrite32(aWrite, pCds->szUncompressed);
    zipfileWrite16(aWrite, pCds->nFile);
    zipfileWrite16(aWrite, pCds->nExtra);
    zipfileWrite16(aWrite, pCds->nComment);      assert( pCds->nComment==0 );
    zipfileWrite16(aWrite, pCds->iDiskStart);
    zipfileWrite16(aWrite, pCds->iInternalAttr);
    zipfileWrite32(aWrite, pCds->iExternalAttr);
    zipfileWrite32(aWrite, pCds->iOffset);
    assert( aWrite==&pNew->aCdsEntry[ZIPFILE_CDS_FIXED_SZ] );
    memcpy(aWrite, zPath, nPath);
    if( pCds->nExtra ){
      aWrite += nPath;
      zipfileWrite16(aWrite, ZIPFILE_EXTRA_TIMESTAMP);
      zipfileWrite16(aWrite, 5);
      *aWrite++ = 0x01;
      zipfileWrite32(aWrite, mTime);
    }
  }

  return pNew;
}

static int zipfileAppendEntry(
  ZipfileTab *pTab,
  ZipfileCDS *pCds,
  const char *zPath,              /* Path for new entry */
  int nPath,                      /* strlen(zPath) */
  const u8 *pData,
  int nData,
  u32 mTime
){
  u8 *aBuf = pTab->aBuffer;
  int rc;

  zipfileWrite32(aBuf, ZIPFILE_SIGNATURE_LFH);
  zipfileWrite16(aBuf, pCds->iVersionExtract);
  zipfileWrite16(aBuf, pCds->flags);
  zipfileWrite16(aBuf, pCds->iCompression);
  zipfileWrite16(aBuf, pCds->mTime);
  zipfileWrite16(aBuf, pCds->mDate);
  zipfileWrite32(aBuf, pCds->crc32);
  zipfileWrite32(aBuf, pCds->szCompressed);
  zipfileWrite32(aBuf, pCds->szUncompressed);
  zipfileWrite16(aBuf, (u16)nPath);
  zipfileWrite16(aBuf, pCds->nExtra);
  assert( aBuf==&pTab->aBuffer[ZIPFILE_LFH_FIXED_SZ] );
  rc = zipfileAppendData(pTab, pTab->aBuffer, (int)(aBuf - pTab->aBuffer));
  if( rc==SQLITE_OK ){
    rc = zipfileAppendData(pTab, (const u8*)zPath, nPath);
  }

  if( rc==SQLITE_OK && pCds->nExtra ){
    aBuf = pTab->aBuffer;
    zipfileWrite16(aBuf, ZIPFILE_EXTRA_TIMESTAMP);
    zipfileWrite16(aBuf, 5);
    *aBuf++ = 0x01;
    zipfileWrite32(aBuf, mTime);
    rc = zipfileAppendData(pTab, pTab->aBuffer, 9);
  }

  if( rc==SQLITE_OK ){
    rc = zipfileAppendData(pTab, pData, nData);
  }

  return rc;
}

static int zipfileGetMode(ZipfileTab *pTab, sqlite3_value *pVal, int *pMode){
  const char *z = (const char*)sqlite3_value_text(pVal);
  int mode = 0;
  if( z==0 || (z[0]>=0 && z[0]<=9) ){
    mode = sqlite3_value_int(pVal);
  }else{
    const char zTemplate[11] = "-rwxrwxrwx";
    int i;
    if( strlen(z)!=10 ) goto parse_error;
    switch( z[0] ){
      case '-': mode |= S_IFREG; break;
      case 'd': mode |= S_IFDIR; break;
#if !defined(_WIN32) && !defined(WIN32)
      case 'l': mode |= S_IFLNK; break;
#endif
      default: goto parse_error;
    }
    for(i=1; i<10; i++){
      if( z[i]==zTemplate[i] ) mode |= 1 << (9-i);
      else if( z[i]!='-' ) goto parse_error;
    }
  }
  *pMode = mode;
  return SQLITE_OK;

 parse_error:
  pTab->base.zErrMsg = sqlite3_mprintf("zipfile: parse error in mode: %s", z);
  return SQLITE_ERROR;
}

/*
** xUpdate method.
*/
static int zipfileUpdate(
  sqlite3_vtab *pVtab, 
  int nVal, 
  sqlite3_value **apVal, 
  sqlite_int64 *pRowid
){
  ZipfileTab *pTab = (ZipfileTab*)pVtab;
  int rc = SQLITE_OK;             /* Return Code */
  ZipfileEntry *pNew = 0;         /* New in-memory CDS entry */

  int mode;                       /* Mode for new entry */
  i64 mTime;                      /* Modification time for new entry */
  i64 sz;                         /* Uncompressed size */
  const char *zPath;              /* Path for new entry */
  int nPath;                      /* strlen(zPath) */
  const u8 *pData;                /* Pointer to buffer containing content */
  int nData;                      /* Size of pData buffer in bytes */
  int iMethod = 0;                /* Compression method for new entry */
  u8 *pFree = 0;                  /* Free this */
  ZipfileCDS cds;                 /* New Central Directory Structure entry */

  assert( pTab->zFile );
  assert( pTab->pWriteFd );

  if( sqlite3_value_type(apVal[0])!=SQLITE_NULL ){
    i64 iDelete = sqlite3_value_int64(apVal[0]);
    ZipfileEntry *p;
    for(p=pTab->pFirstEntry; p; p=p->pNext){
      if( p->iRowid==iDelete ){
        p->bDeleted = 1;
        break;
      }
    }
    if( nVal==1 ) return SQLITE_OK;
  }

  zPath = (const char*)sqlite3_value_text(apVal[2]);
  nPath = (int)strlen(zPath);
  rc = zipfileGetMode(pTab, apVal[3], &mode);
  if( rc!=SQLITE_OK ) return rc;
  mTime = sqlite3_value_int64(apVal[4]);
  sz = sqlite3_value_int(apVal[5]);
  pData = sqlite3_value_blob(apVal[6]);
  nData = sqlite3_value_bytes(apVal[6]);

  /* If a NULL value is inserted into the 'method' column, do automatic
  ** compression. */
  if( nData>0 && sqlite3_value_type(apVal[7])==SQLITE_NULL ){
    pFree = (u8*)sqlite3_malloc(nData);
    if( pFree==0 ){
      rc = SQLITE_NOMEM;
    }else{
      int res;
      z_stream str;
      memset(&str, 0, sizeof(str));
      str.next_in = (z_const Bytef*)pData;
      str.avail_in = nData;
      str.next_out = pFree;
      str.avail_out = nData;
      deflateInit2(&str, 9, Z_DEFLATED, -15, 8, Z_DEFAULT_STRATEGY);
      res = deflate(&str, Z_FINISH);
      if( res==Z_STREAM_END ){
        pData = pFree;
        nData = str.total_out;
        iMethod = 8;
      }else if( res!=Z_OK ){
        pTab->base.zErrMsg = sqlite3_mprintf("zipfile: deflate() error");
        rc = SQLITE_ERROR;
      }
      deflateEnd(&str);
    }
  }else{
    iMethod = sqlite3_value_int(apVal[7]);
    if( iMethod<0 || iMethod>65535 ){
      pTab->base.zErrMsg = sqlite3_mprintf(
          "zipfile: invalid compression method: %d", iMethod
      );
      rc = SQLITE_ERROR;
    }
  }

  if( rc==SQLITE_OK ){
    /* Create the new CDS record. */
    memset(&cds, 0, sizeof(cds));
    cds.iVersionMadeBy = ZIPFILE_NEWENTRY_MADEBY;
    cds.iVersionExtract = ZIPFILE_NEWENTRY_REQUIRED;
    cds.flags = ZIPFILE_NEWENTRY_FLAGS;
    cds.iCompression = (u16)iMethod;
    zipfileMtimeToDos(&cds, (u32)mTime);
    cds.crc32 = crc32(0, pData, nData);
    cds.szCompressed = nData;
    cds.szUncompressed = (u32)sz;
    cds.iExternalAttr = (mode<<16);
    cds.iOffset = (u32)pTab->szCurrent;
    pNew = zipfileNewEntry(&cds, zPath, nPath, (u32)mTime);
    if( pNew==0 ){
      rc = SQLITE_NOMEM;
    }else{
      zipfileAddEntry(pTab, pNew);
    }
  }

  /* Append the new header+file to the archive */
  if( rc==SQLITE_OK ){
    rc = zipfileAppendEntry(pTab, &cds, zPath, nPath, pData, nData, (u32)mTime);
  }

  sqlite3_free(pFree);
  return rc;
}

static int zipfileAppendEOCD(ZipfileTab *pTab, ZipfileEOCD *p){
  u8 *aBuf = pTab->aBuffer;

  zipfileWrite32(aBuf, ZIPFILE_SIGNATURE_EOCD);
  zipfileWrite16(aBuf, p->iDisk);
  zipfileWrite16(aBuf, p->iFirstDisk);
  zipfileWrite16(aBuf, p->nEntry);
  zipfileWrite16(aBuf, p->nEntryTotal);
  zipfileWrite32(aBuf, p->nSize);
  zipfileWrite32(aBuf, p->iOffset);
  zipfileWrite16(aBuf, 0);        /* Size of trailing comment in bytes*/

  assert( (aBuf-pTab->aBuffer)==22 );
  return zipfileAppendData(pTab, pTab->aBuffer, (int)(aBuf - pTab->aBuffer));
}

static void zipfileCleanupTransaction(ZipfileTab *pTab){
  ZipfileEntry *pEntry;
  ZipfileEntry *pNext;

  for(pEntry=pTab->pFirstEntry; pEntry; pEntry=pNext){
    pNext = pEntry->pNext;
    sqlite3_free(pEntry);
  }
  pTab->pFirstEntry = 0;
  pTab->pLastEntry = 0;
  fclose(pTab->pWriteFd);
  pTab->pWriteFd = 0;
  pTab->szCurrent = 0;
  pTab->szOrig = 0;
}

static int zipfileBegin(sqlite3_vtab *pVtab){
  ZipfileTab *pTab = (ZipfileTab*)pVtab;
  int rc = SQLITE_OK;

  assert( pTab->pWriteFd==0 );

  /* This table is only writable if a default archive path was specified 
  ** as part of the CREATE VIRTUAL TABLE statement. */
  if( pTab->zFile==0 ){
    pTab->base.zErrMsg = sqlite3_mprintf(
        "zipfile: writing requires a default archive"
    );
    return SQLITE_ERROR;
  }

  /* Open a write fd on the file. Also load the entire central directory
  ** structure into memory. During the transaction any new file data is 
  ** appended to the archive file, but the central directory is accumulated
  ** in main-memory until the transaction is committed.  */
  pTab->pWriteFd = fopen(pTab->zFile, "ab+");
  if( pTab->pWriteFd==0 ){
    pTab->base.zErrMsg = sqlite3_mprintf(
        "zipfile: failed to open file %s for writing", pTab->zFile
    );
    rc = SQLITE_ERROR;
  }else{
    fseek(pTab->pWriteFd, 0, SEEK_END);
    pTab->szCurrent = pTab->szOrig = (i64)ftell(pTab->pWriteFd);
    rc = zipfileLoadDirectory(pTab);
  }

  if( rc!=SQLITE_OK ){
    zipfileCleanupTransaction(pTab);
  }

  return rc;
}

static int zipfileCommit(sqlite3_vtab *pVtab){
  ZipfileTab *pTab = (ZipfileTab*)pVtab;
  int rc = SQLITE_OK;
  if( pTab->pWriteFd ){
    i64 iOffset = pTab->szCurrent;
    ZipfileEntry *p;
    ZipfileEOCD eocd;
    int nEntry = 0;

    /* Write out all undeleted entries */
    for(p=pTab->pFirstEntry; rc==SQLITE_OK && p; p=p->pNext){
      if( p->bDeleted ) continue;
      rc = zipfileAppendData(pTab, p->aCdsEntry, p->nCdsEntry);
      nEntry++;
    }

    /* Write out the EOCD record */
    eocd.iDisk = 0;
    eocd.iFirstDisk = 0;
    eocd.nEntry = (u16)nEntry;
    eocd.nEntryTotal = (u16)nEntry;
    eocd.nSize = (u32)(pTab->szCurrent - iOffset);
    eocd.iOffset = (u32)iOffset;
    rc = zipfileAppendEOCD(pTab, &eocd);

    zipfileCleanupTransaction(pTab);
  }
  return rc;
}

static int zipfileRollback(sqlite3_vtab *pVtab){
  return zipfileCommit(pVtab);
}

/*
** Register the "zipfile" virtual table.
*/
static int zipfileRegister(sqlite3 *db){
  static sqlite3_module zipfileModule = {
    1,                         /* iVersion */
    zipfileConnect,            /* xCreate */
    zipfileConnect,            /* xConnect */
    zipfileBestIndex,          /* xBestIndex */
    zipfileDisconnect,         /* xDisconnect */
    zipfileDisconnect,         /* xDestroy */
    zipfileOpen,               /* xOpen - open a cursor */
    zipfileClose,              /* xClose - close a cursor */
    zipfileFilter,             /* xFilter - configure scan constraints */
    zipfileNext,               /* xNext - advance a cursor */
    zipfileEof,                /* xEof - check for end of scan */
    zipfileColumn,             /* xColumn - read data */
    zipfileRowid,              /* xRowid - read data */
    zipfileUpdate,             /* xUpdate */
    zipfileBegin,              /* xBegin */
    0,                         /* xSync */
    zipfileCommit,             /* xCommit */
    zipfileRollback,           /* xRollback */
    0,                         /* xFindMethod */
    0,                         /* xRename */
  };

  int rc = sqlite3_create_module(db, "zipfile"  , &zipfileModule, 0);
  return rc;
}
#else         /* SQLITE_OMIT_VIRTUALTABLE */
# define zipfileRegister(x) SQLITE_OK
#endif

/*
** zipfile_uncompress(DATA, SZ, METHOD)
*/
static void zipfileUncompressFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  int iMethod;

  iMethod = sqlite3_value_int(argv[2]);
  if( iMethod==0 ){
    sqlite3_result_value(context, argv[0]);
  }else if( iMethod==8 ){
    Byte *res;
    int sz = sqlite3_value_int(argv[1]);
    z_stream str;
    memset(&str, 0, sizeof(str));
    str.next_in = (Byte*)sqlite3_value_blob(argv[0]);
    str.avail_in = sqlite3_value_bytes(argv[0]);
    res = str.next_out = (Byte*)sqlite3_malloc(sz);
    if( res==0 ){
      sqlite3_result_error_nomem(context);
    }else{
      int err;
      str.avail_out = sz;

      err = inflateInit2(&str, -15);
      if( err!=Z_OK ){
        zipfileCtxErrorMsg(context, "inflateInit2() failed (%d)", err);
      }else{
        err = inflate(&str, Z_NO_FLUSH);
        if( err!=Z_STREAM_END ){
          zipfileCtxErrorMsg(context, "inflate() failed (%d)", err);
        }else{
          sqlite3_result_blob(context, res, sz, SQLITE_TRANSIENT);
        }
      }
      sqlite3_free(res);
      inflateEnd(&str);
    }
  }else{
    zipfileCtxErrorMsg(context, "unrecognized compression method: %d", iMethod);
  }
}

#ifdef _WIN32

#endif
int sqlite3_zipfile_init(
  sqlite3 *db, 
  char **pzErrMsg, 
  const sqlite3_api_routines *pApi
){
  int rc = SQLITE_OK;
  SQLITE_EXTENSION_INIT2(pApi);
  (void)pzErrMsg;  /* Unused parameter */
  rc = sqlite3_create_function(db, "zipfile_uncompress", 3,
      SQLITE_UTF8, 0, zipfileUncompressFunc, 0, 0
  );
  if( rc!=SQLITE_OK ) return rc;
  return zipfileRegister(db);
}


/************************* End ../ext/misc/zipfile.c ********************/
/************************* Begin ../ext/misc/sqlar.c ******************/
/*
** 2017-12-17
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** Utility functions sqlar_compress() and sqlar_uncompress(). Useful
** for working with sqlar archives and used by the shell tool's built-in
** sqlar support.
*/
SQLITE_EXTENSION_INIT1
#include <zlib.h>

/*
** Implementation of the "sqlar_compress(X)" SQL function.
**
** If the type of X is SQLITE_BLOB, and compressing that blob using
** zlib utility function compress() yields a smaller blob, return the
** compressed blob. Otherwise, return a copy of X.
**
** SQLar uses the "zlib format" for compressed content.  The zlib format
** contains a two-byte identification header and a four-byte checksum at
** the end.  This is different from ZIP which uses the raw deflate format.
**
** Future enhancements to SQLar might add support for new compression formats.
** If so, those new formats will be identified by alternative headers in the
** compressed data.
*/
static void sqlarCompressFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  assert( argc==1 );
  if( sqlite3_value_type(argv[0])==SQLITE_BLOB ){
    const Bytef *pData = sqlite3_value_blob(argv[0]);
    uLong nData = sqlite3_value_bytes(argv[0]);
    uLongf nOut = compressBound(nData);
    Bytef *pOut;

    pOut = (Bytef*)sqlite3_malloc(nOut);
    if( pOut==0 ){
      sqlite3_result_error_nomem(context);
      return;
    }else{
      if( Z_OK!=compress(pOut, &nOut, pData, nData) ){
        sqlite3_result_error(context, "error in compress()", -1);
      }else if( nOut<nData ){
        sqlite3_result_blob(context, pOut, nOut, SQLITE_TRANSIENT);
      }else{
        sqlite3_result_value(context, argv[0]);
      }
      sqlite3_free(pOut);
    }
  }else{
    sqlite3_result_value(context, argv[0]);
  }
}

/*
** Implementation of the "sqlar_uncompress(X,SZ)" SQL function
**
** Parameter SZ is interpreted as an integer. If it is less than or
** equal to zero, then this function returns a copy of X. Or, if
** SZ is equal to the size of X when interpreted as a blob, also
** return a copy of X. Otherwise, decompress blob X using zlib
** utility function uncompress() and return the results (another
** blob).
*/
static void sqlarUncompressFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  uLong nData;
  uLongf sz;

  assert( argc==2 );
  sz = sqlite3_value_int(argv[1]);

  if( sz<=0 || sz==(nData = sqlite3_value_bytes(argv[0])) ){
    sqlite3_result_value(context, argv[0]);
  }else{
    const Bytef *pData= sqlite3_value_blob(argv[0]);
    Bytef *pOut = sqlite3_malloc(sz);
    if( Z_OK!=uncompress(pOut, &sz, pData, nData) ){
      sqlite3_result_error(context, "error in uncompress()", -1);
    }else{
      sqlite3_result_blob(context, pOut, sz, SQLITE_TRANSIENT);
    }
    sqlite3_free(pOut);
  }
}


#ifdef _WIN32

#endif
int sqlite3_sqlar_init(
  sqlite3 *db, 
  char **pzErrMsg, 
  const sqlite3_api_routines *pApi
){
  int rc = SQLITE_OK;
  SQLITE_EXTENSION_INIT2(pApi);
  (void)pzErrMsg;  /* Unused parameter */
  rc = sqlite3_create_function(db, "sqlar_compress", 1, SQLITE_UTF8, 0,
                               sqlarCompressFunc, 0, 0);
  if( rc==SQLITE_OK ){
    rc = sqlite3_create_function(db, "sqlar_uncompress", 2, SQLITE_UTF8, 0,
                                 sqlarUncompressFunc, 0, 0);
  }
  return rc;
}

/************************* End ../ext/misc/sqlar.c ********************/
#endif
/************************* Begin ../ext/expert/sqlite3expert.h ******************/
/*
** 2017 April 07
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
*/



typedef struct sqlite3expert sqlite3expert;

/*
** Create a new sqlite3expert object.
**
** If successful, a pointer to the new object is returned and (*pzErr) set
** to NULL. Or, if an error occurs, NULL is returned and (*pzErr) set to
** an English-language error message. In this case it is the responsibility
** of the caller to eventually free the error message buffer using
** sqlite3_free().
*/
sqlite3expert *sqlite3_expert_new(sqlite3 *db, char **pzErr);

/*
** Configure an sqlite3expert object.
**
** EXPERT_CONFIG_SAMPLE:
**   By default, sqlite3_expert_analyze() generates sqlite_stat1 data for
**   each candidate index. This involves scanning and sorting the entire
**   contents of each user database table once for each candidate index
**   associated with the table. For large databases, this can be 
**   prohibitively slow. This option allows the sqlite3expert object to
**   be configured so that sqlite_stat1 data is instead generated based on a
**   subset of each table, or so that no sqlite_stat1 data is used at all.
**
**   A single integer argument is passed to this option. If the value is less
**   than or equal to zero, then no sqlite_stat1 data is generated or used by
**   the analysis - indexes are recommended based on the database schema only.
**   Or, if the value is 100 or greater, complete sqlite_stat1 data is
**   generated for each candidate index (this is the default). Finally, if the
**   value falls between 0 and 100, then it represents the percentage of user
**   table rows that should be considered when generating sqlite_stat1 data.
**
**   Examples:
**
**     // Do not generate any sqlite_stat1 data
**     sqlite3_expert_config(pExpert, EXPERT_CONFIG_SAMPLE, 0);
**
**     // Generate sqlite_stat1 data based on 10% of the rows in each table.
**     sqlite3_expert_config(pExpert, EXPERT_CONFIG_SAMPLE, 10);
*/
int sqlite3_expert_config(sqlite3expert *p, int op, ...);

#define EXPERT_CONFIG_SAMPLE 1    /* int */

/*
** Specify zero or more SQL statements to be included in the analysis.
**
** Buffer zSql must contain zero or more complete SQL statements. This
** function parses all statements contained in the buffer and adds them
** to the internal list of statements to analyze. If successful, SQLITE_OK
** is returned and (*pzErr) set to NULL. Or, if an error occurs - for example
** due to a error in the SQL - an SQLite error code is returned and (*pzErr)
** may be set to point to an English language error message. In this case
** the caller is responsible for eventually freeing the error message buffer
** using sqlite3_free().
**
** If an error does occur while processing one of the statements in the
** buffer passed as the second argument, none of the statements in the
** buffer are added to the analysis.
**
** This function must be called before sqlite3_expert_analyze(). If a call
** to this function is made on an sqlite3expert object that has already
** been passed to sqlite3_expert_analyze() SQLITE_MISUSE is returned
** immediately and no statements are added to the analysis.
*/
int sqlite3_expert_sql(
  sqlite3expert *p,               /* From a successful sqlite3_expert_new() */
  const char *zSql,               /* SQL statement(s) to add */
  char **pzErr                    /* OUT: Error message (if any) */
);


/*
** This function is called after the sqlite3expert object has been configured
** with all SQL statements using sqlite3_expert_sql() to actually perform
** the analysis. Once this function has been called, it is not possible to
** add further SQL statements to the analysis.
**
** If successful, SQLITE_OK is returned and (*pzErr) is set to NULL. Or, if
** an error occurs, an SQLite error code is returned and (*pzErr) set to 
** point to a buffer containing an English language error message. In this
** case it is the responsibility of the caller to eventually free the buffer
** using sqlite3_free().
**
** If an error does occur within this function, the sqlite3expert object
** is no longer useful for any purpose. At that point it is no longer
** possible to add further SQL statements to the object or to re-attempt
** the analysis. The sqlite3expert object must still be freed using a call
** sqlite3_expert_destroy().
*/
int sqlite3_expert_analyze(sqlite3expert *p, char **pzErr);

/*
** Return the total number of statements loaded using sqlite3_expert_sql().
** The total number of SQL statements may be different from the total number
** to calls to sqlite3_expert_sql().
*/
int sqlite3_expert_count(sqlite3expert*);

/*
** Return a component of the report.
**
** This function is called after sqlite3_expert_analyze() to extract the
** results of the analysis. Each call to this function returns either a
** NULL pointer or a pointer to a buffer containing a nul-terminated string.
** The value passed as the third argument must be one of the EXPERT_REPORT_*
** #define constants defined below.
**
** For some EXPERT_REPORT_* parameters, the buffer returned contains 
** information relating to a specific SQL statement. In these cases that
** SQL statement is identified by the value passed as the second argument.
** SQL statements are numbered from 0 in the order in which they are parsed.
** If an out-of-range value (less than zero or equal to or greater than the
** value returned by sqlite3_expert_count()) is passed as the second argument
** along with such an EXPERT_REPORT_* parameter, NULL is always returned.
**
** EXPERT_REPORT_SQL:
**   Return the text of SQL statement iStmt.
**
** EXPERT_REPORT_INDEXES:
**   Return a buffer containing the CREATE INDEX statements for all recommended
**   indexes for statement iStmt. If there are no new recommeded indexes, NULL 
**   is returned.
**
** EXPERT_REPORT_PLAN:
**   Return a buffer containing the EXPLAIN QUERY PLAN output for SQL query
**   iStmt after the proposed indexes have been added to the database schema.
**
** EXPERT_REPORT_CANDIDATES:
**   Return a pointer to a buffer containing the CREATE INDEX statements 
**   for all indexes that were tested (for all SQL statements). The iStmt
**   parameter is ignored for EXPERT_REPORT_CANDIDATES calls.
*/
const char *sqlite3_expert_report(sqlite3expert*, int iStmt, int eReport);

/*
** Values for the third argument passed to sqlite3_expert_report().
*/
#define EXPERT_REPORT_SQL        1
#define EXPERT_REPORT_INDEXES    2
#define EXPERT_REPORT_PLAN       3
#define EXPERT_REPORT_CANDIDATES 4

/*
** Free an (sqlite3expert*) handle and all associated resources. There 
** should be one call to this function for each successful call to 
** sqlite3-expert_new().
*/
void sqlite3_expert_destroy(sqlite3expert*);



/************************* End ../ext/expert/sqlite3expert.h ********************/
/************************* Begin ../ext/expert/sqlite3expert.c ******************/
/*
** 2017 April 09
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
*/
#include <assert.h>
#include <string.h>
#include <stdio.h>

/* typedef sqlite3_int64 i64; */
/* typedef sqlite3_uint64 u64; */

typedef struct IdxColumn IdxColumn;
typedef struct IdxConstraint IdxConstraint;
typedef struct IdxScan IdxScan;
typedef struct IdxStatement IdxStatement;
typedef struct IdxTable IdxTable;
typedef struct IdxWrite IdxWrite;

#define STRLEN  (int)strlen

/*
** A temp table name that we assume no user database will actually use.
** If this assumption proves incorrect triggers on the table with the
** conflicting name will be ignored.
*/
#define UNIQUE_TABLE_NAME "t592690916721053953805701627921227776"

/*
** A single constraint. Equivalent to either "col = ?" or "col < ?" (or
** any other type of single-ended range constraint on a column).
**
** pLink:
**   Used to temporarily link IdxConstraint objects into lists while
**   creating candidate indexes.
*/
struct IdxConstraint {
  char *zColl;                    /* Collation sequence */
  int bRange;                     /* True for range, false for eq */
  int iCol;                       /* Constrained table column */
  int bFlag;                      /* Used by idxFindCompatible() */
  int bDesc;                      /* True if ORDER BY <expr> DESC */
  IdxConstraint *pNext;           /* Next constraint in pEq or pRange list */
  IdxConstraint *pLink;           /* See above */
};

/*
** A single scan of a single table.
*/
struct IdxScan {
  IdxTable *pTab;                 /* Associated table object */
  int iDb;                        /* Database containing table zTable */
  i64 covering;                   /* Mask of columns required for cov. index */
  IdxConstraint *pOrder;          /* ORDER BY columns */
  IdxConstraint *pEq;             /* List of == constraints */
  IdxConstraint *pRange;          /* List of < constraints */
  IdxScan *pNextScan;             /* Next IdxScan object for same analysis */
};

/*
** Information regarding a single database table. Extracted from 
** "PRAGMA table_info" by function idxGetTableInfo().
*/
struct IdxColumn {
  char *zName;
  char *zColl;
  int iPk;
};
struct IdxTable {
  int nCol;
  char *zName;                    /* Table name */
  IdxColumn *aCol;
  IdxTable *pNext;                /* Next table in linked list of all tables */
};

/*
** An object of the following type is created for each unique table/write-op
** seen. The objects are stored in a singly-linked list beginning at
** sqlite3expert.pWrite.
*/
struct IdxWrite {
  IdxTable *pTab;
  int eOp;                        /* SQLITE_UPDATE, DELETE or INSERT */
  IdxWrite *pNext;
};

/*
** Each statement being analyzed is represented by an instance of this
** structure.
*/
struct IdxStatement {
  int iId;                        /* Statement number */
  char *zSql;                     /* SQL statement */
  char *zIdx;                     /* Indexes */
  char *zEQP;                     /* Plan */
  IdxStatement *pNext;
};


/*
** A hash table for storing strings. With space for a payload string
** with each entry. Methods are:
**
**   idxHashInit()
**   idxHashClear()
**   idxHashAdd()
**   idxHashSearch()
*/
#define IDX_HASH_SIZE 1023
typedef struct IdxHashEntry IdxHashEntry;
typedef struct IdxHash IdxHash;
struct IdxHashEntry {
  char *zKey;                     /* nul-terminated key */
  char *zVal;                     /* nul-terminated value string */
  char *zVal2;                    /* nul-terminated value string 2 */
  IdxHashEntry *pHashNext;        /* Next entry in same hash bucket */
  IdxHashEntry *pNext;            /* Next entry in hash */
};
struct IdxHash {
  IdxHashEntry *pFirst;
  IdxHashEntry *aHash[IDX_HASH_SIZE];
};

/*
** sqlite3expert object.
*/
struct sqlite3expert {
  int iSample;                    /* Percentage of tables to sample for stat1 */
  sqlite3 *db;                    /* User database */
  sqlite3 *dbm;                   /* In-memory db for this analysis */
  sqlite3 *dbv;                   /* Vtab schema for this analysis */
  IdxTable *pTable;               /* List of all IdxTable objects */
  IdxScan *pScan;                 /* List of scan objects */
  IdxWrite *pWrite;               /* List of write objects */
  IdxStatement *pStatement;       /* List of IdxStatement objects */
  int bRun;                       /* True once analysis has run */
  char **pzErrmsg;
  int rc;                         /* Error code from whereinfo hook */
  IdxHash hIdx;                   /* Hash containing all candidate indexes */
  char *zCandidates;              /* For EXPERT_REPORT_CANDIDATES */
};


/*
** Allocate and return nByte bytes of zeroed memory using sqlite3_malloc(). 
** If the allocation fails, set *pRc to SQLITE_NOMEM and return NULL.
*/
static void *idxMalloc(int *pRc, int nByte){
  void *pRet;
  assert( *pRc==SQLITE_OK );
  assert( nByte>0 );
  pRet = sqlite3_malloc(nByte);
  if( pRet ){
    memset(pRet, 0, nByte);
  }else{
    *pRc = SQLITE_NOMEM;
  }
  return pRet;
}

/*
** Initialize an IdxHash hash table.
*/
static void idxHashInit(IdxHash *pHash){
  memset(pHash, 0, sizeof(IdxHash));
}

/*
** Reset an IdxHash hash table.
*/
static void idxHashClear(IdxHash *pHash){
  int i;
  for(i=0; i<IDX_HASH_SIZE; i++){
    IdxHashEntry *pEntry;
    IdxHashEntry *pNext;
    for(pEntry=pHash->aHash[i]; pEntry; pEntry=pNext){
      pNext = pEntry->pHashNext;
      sqlite3_free(pEntry->zVal2);
      sqlite3_free(pEntry);
    }
  }
  memset(pHash, 0, sizeof(IdxHash));
}

/*
** Return the index of the hash bucket that the string specified by the
** arguments to this function belongs.
*/
static int idxHashString(const char *z, int n){
  unsigned int ret = 0;
  int i;
  for(i=0; i<n; i++){
    ret += (ret<<3) + (unsigned char)(z[i]);
  }
  return (int)(ret % IDX_HASH_SIZE);
}

/*
** If zKey is already present in the hash table, return non-zero and do
** nothing. Otherwise, add an entry with key zKey and payload string zVal to
** the hash table passed as the second argument. 
*/
static int idxHashAdd(
  int *pRc, 
  IdxHash *pHash, 
  const char *zKey,
  const char *zVal
){
  int nKey = STRLEN(zKey);
  int iHash = idxHashString(zKey, nKey);
  int nVal = (zVal ? STRLEN(zVal) : 0);
  IdxHashEntry *pEntry;
  assert( iHash>=0 );
  for(pEntry=pHash->aHash[iHash]; pEntry; pEntry=pEntry->pHashNext){
    if( STRLEN(pEntry->zKey)==nKey && 0==memcmp(pEntry->zKey, zKey, nKey) ){
      return 1;
    }
  }
  pEntry = idxMalloc(pRc, sizeof(IdxHashEntry) + nKey+1 + nVal+1);
  if( pEntry ){
    pEntry->zKey = (char*)&pEntry[1];
    memcpy(pEntry->zKey, zKey, nKey);
    if( zVal ){
      pEntry->zVal = &pEntry->zKey[nKey+1];
      memcpy(pEntry->zVal, zVal, nVal);
    }
    pEntry->pHashNext = pHash->aHash[iHash];
    pHash->aHash[iHash] = pEntry;

    pEntry->pNext = pHash->pFirst;
    pHash->pFirst = pEntry;
  }
  return 0;
}

/*
** If zKey/nKey is present in the hash table, return a pointer to the 
** hash-entry object.
*/
static IdxHashEntry *idxHashFind(IdxHash *pHash, const char *zKey, int nKey){
  int iHash;
  IdxHashEntry *pEntry;
  if( nKey<0 ) nKey = STRLEN(zKey);
  iHash = idxHashString(zKey, nKey);
  assert( iHash>=0 );
  for(pEntry=pHash->aHash[iHash]; pEntry; pEntry=pEntry->pHashNext){
    if( STRLEN(pEntry->zKey)==nKey && 0==memcmp(pEntry->zKey, zKey, nKey) ){
      return pEntry;
    }
  }
  return 0;
}

/*
** If the hash table contains an entry with a key equal to the string
** passed as the final two arguments to this function, return a pointer
** to the payload string. Otherwise, if zKey/nKey is not present in the
** hash table, return NULL.
*/
static const char *idxHashSearch(IdxHash *pHash, const char *zKey, int nKey){
  IdxHashEntry *pEntry = idxHashFind(pHash, zKey, nKey);
  if( pEntry ) return pEntry->zVal;
  return 0;
}

/*
** Allocate and return a new IdxConstraint object. Set the IdxConstraint.zColl
** variable to point to a copy of nul-terminated string zColl.
*/
static IdxConstraint *idxNewConstraint(int *pRc, const char *zColl){
  IdxConstraint *pNew;
  int nColl = STRLEN(zColl);

  assert( *pRc==SQLITE_OK );
  pNew = (IdxConstraint*)idxMalloc(pRc, sizeof(IdxConstraint) * nColl + 1);
  if( pNew ){
    pNew->zColl = (char*)&pNew[1];
    memcpy(pNew->zColl, zColl, nColl+1);
  }
  return pNew;
}

/*
** An error associated with database handle db has just occurred. Pass
** the error message to callback function xOut.
*/
static void idxDatabaseError(
  sqlite3 *db,                    /* Database handle */
  char **pzErrmsg                 /* Write error here */
){
  *pzErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(db));
}

/*
** Prepare an SQL statement.
*/
static int idxPrepareStmt(
  sqlite3 *db,                    /* Database handle to compile against */
  sqlite3_stmt **ppStmt,          /* OUT: Compiled SQL statement */
  char **pzErrmsg,                /* OUT: sqlite3_malloc()ed error message */
  const char *zSql                /* SQL statement to compile */
){
  int rc = sqlite3_prepare_v2(db, zSql, -1, ppStmt, 0);
  if( rc!=SQLITE_OK ){
    *ppStmt = 0;
    idxDatabaseError(db, pzErrmsg);
  }
  return rc;
}

/*
** Prepare an SQL statement using the results of a printf() formatting.
*/
static int idxPrintfPrepareStmt(
  sqlite3 *db,                    /* Database handle to compile against */
  sqlite3_stmt **ppStmt,          /* OUT: Compiled SQL statement */
  char **pzErrmsg,                /* OUT: sqlite3_malloc()ed error message */
  const char *zFmt,               /* printf() format of SQL statement */
  ...                             /* Trailing printf() arguments */
){
  va_list ap;
  int rc;
  char *zSql;
  va_start(ap, zFmt);
  zSql = sqlite3_vmprintf(zFmt, ap);
  if( zSql==0 ){
    rc = SQLITE_NOMEM;
  }else{
    rc = idxPrepareStmt(db, ppStmt, pzErrmsg, zSql);
    sqlite3_free(zSql);
  }
  va_end(ap);
  return rc;
}


/*************************************************************************
** Beginning of virtual table implementation.
*/
typedef struct ExpertVtab ExpertVtab;
struct ExpertVtab {
  sqlite3_vtab base;
  IdxTable *pTab;
  sqlite3expert *pExpert;
};

typedef struct ExpertCsr ExpertCsr;
struct ExpertCsr {
  sqlite3_vtab_cursor base;
  sqlite3_stmt *pData;
};

static char *expertDequote(const char *zIn){
  int n = STRLEN(zIn);
  char *zRet = sqlite3_malloc(n);

  assert( zIn[0]=='\'' );
  assert( zIn[n-1]=='\'' );

  if( zRet ){
    int iOut = 0;
    int iIn = 0;
    for(iIn=1; iIn<(n-1); iIn++){
      if( zIn[iIn]=='\'' ){
        assert( zIn[iIn+1]=='\'' );
        iIn++;
      }
      zRet[iOut++] = zIn[iIn];
    }
    zRet[iOut] = '\0';
  }

  return zRet;
}

/* 
** This function is the implementation of both the xConnect and xCreate
** methods of the r-tree virtual table.
**
**   argv[0]   -> module name
**   argv[1]   -> database name
**   argv[2]   -> table name
**   argv[...] -> column names...
*/
static int expertConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  sqlite3expert *pExpert = (sqlite3expert*)pAux;
  ExpertVtab *p = 0;
  int rc;

  if( argc!=4 ){
    *pzErr = sqlite3_mprintf("internal error!");
    rc = SQLITE_ERROR;
  }else{
    char *zCreateTable = expertDequote(argv[3]);
    if( zCreateTable ){
      rc = sqlite3_declare_vtab(db, zCreateTable);
      if( rc==SQLITE_OK ){
        p = idxMalloc(&rc, sizeof(ExpertVtab));
      }
      if( rc==SQLITE_OK ){
        p->pExpert = pExpert;
        p->pTab = pExpert->pTable;
        assert( sqlite3_stricmp(p->pTab->zName, argv[2])==0 );
      }
      sqlite3_free(zCreateTable);
    }else{
      rc = SQLITE_NOMEM;
    }
  }

  *ppVtab = (sqlite3_vtab*)p;
  return rc;
}

static int expertDisconnect(sqlite3_vtab *pVtab){
  ExpertVtab *p = (ExpertVtab*)pVtab;
  sqlite3_free(p);
  return SQLITE_OK;
}

static int expertBestIndex(sqlite3_vtab *pVtab, sqlite3_index_info *pIdxInfo){
  ExpertVtab *p = (ExpertVtab*)pVtab;
  int rc = SQLITE_OK;
  int n = 0;
  IdxScan *pScan;
  const int opmask = 
    SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_GT |
    SQLITE_INDEX_CONSTRAINT_LT | SQLITE_INDEX_CONSTRAINT_GE |
    SQLITE_INDEX_CONSTRAINT_LE;

  pScan = idxMalloc(&rc, sizeof(IdxScan));
  if( pScan ){
    int i;

    /* Link the new scan object into the list */
    pScan->pTab = p->pTab;
    pScan->pNextScan = p->pExpert->pScan;
    p->pExpert->pScan = pScan;

    /* Add the constraints to the IdxScan object */
    for(i=0; i<pIdxInfo->nConstraint; i++){
      struct sqlite3_index_constraint *pCons = &pIdxInfo->aConstraint[i];
      if( pCons->usable 
       && pCons->iColumn>=0 
       && p->pTab->aCol[pCons->iColumn].iPk==0
       && (pCons->op & opmask) 
      ){
        IdxConstraint *pNew;
        const char *zColl = sqlite3_vtab_collation(pIdxInfo, i);
        pNew = idxNewConstraint(&rc, zColl);
        if( pNew ){
          pNew->iCol = pCons->iColumn;
          if( pCons->op==SQLITE_INDEX_CONSTRAINT_EQ ){
            pNew->pNext = pScan->pEq;
            pScan->pEq = pNew;
          }else{
            pNew->bRange = 1;
            pNew->pNext = pScan->pRange;
            pScan->pRange = pNew;
          }
        }
        n++;
        pIdxInfo->aConstraintUsage[i].argvIndex = n;
      }
    }

    /* Add the ORDER BY to the IdxScan object */
    for(i=pIdxInfo->nOrderBy-1; i>=0; i--){
      int iCol = pIdxInfo->aOrderBy[i].iColumn;
      if( iCol>=0 ){
        IdxConstraint *pNew = idxNewConstraint(&rc, p->pTab->aCol[iCol].zColl);
        if( pNew ){
          pNew->iCol = iCol;
          pNew->bDesc = pIdxInfo->aOrderBy[i].desc;
          pNew->pNext = pScan->pOrder;
          pNew->pLink = pScan->pOrder;
          pScan->pOrder = pNew;
          n++;
        }
      }
    }
  }

  pIdxInfo->estimatedCost = 1000000.0 / n;
  return rc;
}

static int expertUpdate(
  sqlite3_vtab *pVtab, 
  int nData, 
  sqlite3_value **azData, 
  sqlite_int64 *pRowid
){
  return SQLITE_OK;
}

/* 
** Virtual table module xOpen method.
*/
static int expertOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
  int rc = SQLITE_OK;
  ExpertCsr *pCsr;
  pCsr = idxMalloc(&rc, sizeof(ExpertCsr));
  *ppCursor = (sqlite3_vtab_cursor*)pCsr;
  return rc;
}

/* 
** Virtual table module xClose method.
*/
static int expertClose(sqlite3_vtab_cursor *cur){
  ExpertCsr *pCsr = (ExpertCsr*)cur;
  sqlite3_finalize(pCsr->pData);
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

/*
** Virtual table module xEof method.
**
** Return non-zero if the cursor does not currently point to a valid 
** record (i.e if the scan has finished), or zero otherwise.
*/
static int expertEof(sqlite3_vtab_cursor *cur){
  ExpertCsr *pCsr = (ExpertCsr*)cur;
  return pCsr->pData==0;
}

/* 
** Virtual table module xNext method.
*/
static int expertNext(sqlite3_vtab_cursor *cur){
  ExpertCsr *pCsr = (ExpertCsr*)cur;
  int rc = SQLITE_OK;

  assert( pCsr->pData );
  rc = sqlite3_step(pCsr->pData);
  if( rc!=SQLITE_ROW ){
    rc = sqlite3_finalize(pCsr->pData);
    pCsr->pData = 0;
  }else{
    rc = SQLITE_OK;
  }

  return rc;
}

/* 
** Virtual table module xRowid method.
*/
static int expertRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
  *pRowid = 0;
  return SQLITE_OK;
}

/* 
** Virtual table module xColumn method.
*/
static int expertColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
  ExpertCsr *pCsr = (ExpertCsr*)cur;
  sqlite3_value *pVal;
  pVal = sqlite3_column_value(pCsr->pData, i);
  if( pVal ){
    sqlite3_result_value(ctx, pVal);
  }
  return SQLITE_OK;
}

/* 
** Virtual table module xFilter method.
*/
static int expertFilter(
  sqlite3_vtab_cursor *cur, 
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  ExpertCsr *pCsr = (ExpertCsr*)cur;
  ExpertVtab *pVtab = (ExpertVtab*)(cur->pVtab);
  sqlite3expert *pExpert = pVtab->pExpert;
  int rc;

  rc = sqlite3_finalize(pCsr->pData);
  pCsr->pData = 0;
  if( rc==SQLITE_OK ){
    rc = idxPrintfPrepareStmt(pExpert->db, &pCsr->pData, &pVtab->base.zErrMsg,
        "SELECT * FROM main.%Q WHERE sample()", pVtab->pTab->zName
    );
  }

  if( rc==SQLITE_OK ){
    rc = expertNext(cur);
  }
  return rc;
}

static int idxRegisterVtab(sqlite3expert *p){
  static sqlite3_module expertModule = {
    2,                            /* iVersion */
    expertConnect,                /* xCreate - create a table */
    expertConnect,                /* xConnect - connect to an existing table */
    expertBestIndex,              /* xBestIndex - Determine search strategy */
    expertDisconnect,             /* xDisconnect - Disconnect from a table */
    expertDisconnect,             /* xDestroy - Drop a table */
    expertOpen,                   /* xOpen - open a cursor */
    expertClose,                  /* xClose - close a cursor */
    expertFilter,                 /* xFilter - configure scan constraints */
    expertNext,                   /* xNext - advance a cursor */
    expertEof,                    /* xEof */
    expertColumn,                 /* xColumn - read data */
    expertRowid,                  /* xRowid - read data */
    expertUpdate,                 /* xUpdate - write data */
    0,                            /* xBegin - begin transaction */
    0,                            /* xSync - sync transaction */
    0,                            /* xCommit - commit transaction */
    0,                            /* xRollback - rollback transaction */
    0,                            /* xFindFunction - function overloading */
    0,                            /* xRename - rename the table */
    0,                            /* xSavepoint */
    0,                            /* xRelease */
    0,                            /* xRollbackTo */
  };

  return sqlite3_create_module(p->dbv, "expert", &expertModule, (void*)p);
}
/*
** End of virtual table implementation.
*************************************************************************/
/*
** Finalize SQL statement pStmt. If (*pRc) is SQLITE_OK when this function
** is called, set it to the return value of sqlite3_finalize() before
** returning. Otherwise, discard the sqlite3_finalize() return value.
*/
static void idxFinalize(int *pRc, sqlite3_stmt *pStmt){
  int rc = sqlite3_finalize(pStmt);
  if( *pRc==SQLITE_OK ) *pRc = rc;
}

/*
** Attempt to allocate an IdxTable structure corresponding to table zTab
** in the main database of connection db. If successful, set (*ppOut) to
** point to the new object and return SQLITE_OK. Otherwise, return an
** SQLite error code and set (*ppOut) to NULL. In this case *pzErrmsg may be
** set to point to an error string.
**
** It is the responsibility of the caller to eventually free either the
** IdxTable object or error message using sqlite3_free().
*/
static int idxGetTableInfo(
  sqlite3 *db,                    /* Database connection to read details from */
  const char *zTab,               /* Table name */
  IdxTable **ppOut,               /* OUT: New object (if successful) */
  char **pzErrmsg                 /* OUT: Error message (if not) */
){
  sqlite3_stmt *p1 = 0;
  int nCol = 0;
  int nTab = STRLEN(zTab);
  int nByte = sizeof(IdxTable) + nTab + 1;
  IdxTable *pNew = 0;
  int rc, rc2;
  char *pCsr = 0;

  rc = idxPrintfPrepareStmt(db, &p1, pzErrmsg, "PRAGMA table_info=%Q", zTab);
  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(p1) ){
    const char *zCol = (const char*)sqlite3_column_text(p1, 1);
    nByte += 1 + STRLEN(zCol);
    rc = sqlite3_table_column_metadata(
        db, "main", zTab, zCol, 0, &zCol, 0, 0, 0
    );
    nByte += 1 + STRLEN(zCol);
    nCol++;
  }
  rc2 = sqlite3_reset(p1);
  if( rc==SQLITE_OK ) rc = rc2;

  nByte += sizeof(IdxColumn) * nCol;
  if( rc==SQLITE_OK ){
    pNew = idxMalloc(&rc, nByte);
  }
  if( rc==SQLITE_OK ){
    pNew->aCol = (IdxColumn*)&pNew[1];
    pNew->nCol = nCol;
    pCsr = (char*)&pNew->aCol[nCol];
  }

  nCol = 0;
  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(p1) ){
    const char *zCol = (const char*)sqlite3_column_text(p1, 1);
    int nCopy = STRLEN(zCol) + 1;
    pNew->aCol[nCol].zName = pCsr;
    pNew->aCol[nCol].iPk = sqlite3_column_int(p1, 5);
    memcpy(pCsr, zCol, nCopy);
    pCsr += nCopy;

    rc = sqlite3_table_column_metadata(
        db, "main", zTab, zCol, 0, &zCol, 0, 0, 0
    );
    if( rc==SQLITE_OK ){
      nCopy = STRLEN(zCol) + 1;
      pNew->aCol[nCol].zColl = pCsr;
      memcpy(pCsr, zCol, nCopy);
      pCsr += nCopy;
    }

    nCol++;
  }
  idxFinalize(&rc, p1);

  if( rc!=SQLITE_OK ){
    sqlite3_free(pNew);
    pNew = 0;
  }else{
    pNew->zName = pCsr;
    memcpy(pNew->zName, zTab, nTab+1);
  }

  *ppOut = pNew;
  return rc;
}

/*
** This function is a no-op if *pRc is set to anything other than 
** SQLITE_OK when it is called.
**
** If *pRc is initially set to SQLITE_OK, then the text specified by
** the printf() style arguments is appended to zIn and the result returned
** in a buffer allocated by sqlite3_malloc(). sqlite3_free() is called on
** zIn before returning.
*/
static char *idxAppendText(int *pRc, char *zIn, const char *zFmt, ...){
  va_list ap;
  char *zAppend = 0;
  char *zRet = 0;
  int nIn = zIn ? STRLEN(zIn) : 0;
  int nAppend = 0;
  va_start(ap, zFmt);
  if( *pRc==SQLITE_OK ){
    zAppend = sqlite3_vmprintf(zFmt, ap);
    if( zAppend ){
      nAppend = STRLEN(zAppend);
      zRet = (char*)sqlite3_malloc(nIn + nAppend + 1);
    }
    if( zAppend && zRet ){
      memcpy(zRet, zIn, nIn);
      memcpy(&zRet[nIn], zAppend, nAppend+1);
    }else{
      sqlite3_free(zRet);
      zRet = 0;
      *pRc = SQLITE_NOMEM;
    }
    sqlite3_free(zAppend);
    sqlite3_free(zIn);
  }
  va_end(ap);
  return zRet;
}

/*
** Return true if zId must be quoted in order to use it as an SQL
** identifier, or false otherwise.
*/
static int idxIdentifierRequiresQuotes(const char *zId){
  int i;
  for(i=0; zId[i]; i++){
    if( !(zId[i]=='_')
     && !(zId[i]>='0' && zId[i]<='9')
     && !(zId[i]>='a' && zId[i]<='z')
     && !(zId[i]>='A' && zId[i]<='Z')
    ){
      return 1;
    }
  }
  return 0;
}

/*
** This function appends an index column definition suitable for constraint
** pCons to the string passed as zIn and returns the result.
*/
static char *idxAppendColDefn(
  int *pRc,                       /* IN/OUT: Error code */
  char *zIn,                      /* Column defn accumulated so far */
  IdxTable *pTab,                 /* Table index will be created on */
  IdxConstraint *pCons
){
  char *zRet = zIn;
  IdxColumn *p = &pTab->aCol[pCons->iCol];
  if( zRet ) zRet = idxAppendText(pRc, zRet, ", ");

  if( idxIdentifierRequiresQuotes(p->zName) ){
    zRet = idxAppendText(pRc, zRet, "%Q", p->zName);
  }else{
    zRet = idxAppendText(pRc, zRet, "%s", p->zName);
  }

  if( sqlite3_stricmp(p->zColl, pCons->zColl) ){
    if( idxIdentifierRequiresQuotes(pCons->zColl) ){
      zRet = idxAppendText(pRc, zRet, " COLLATE %Q", pCons->zColl);
    }else{
      zRet = idxAppendText(pRc, zRet, " COLLATE %s", pCons->zColl);
    }
  }

  if( pCons->bDesc ){
    zRet = idxAppendText(pRc, zRet, " DESC");
  }
  return zRet;
}

/*
** Search database dbm for an index compatible with the one idxCreateFromCons()
** would create from arguments pScan, pEq and pTail. If no error occurs and 
** such an index is found, return non-zero. Or, if no such index is found,
** return zero.
**
** If an error occurs, set *pRc to an SQLite error code and return zero.
*/
static int idxFindCompatible(
  int *pRc,                       /* OUT: Error code */
  sqlite3* dbm,                   /* Database to search */
  IdxScan *pScan,                 /* Scan for table to search for index on */
  IdxConstraint *pEq,             /* List of == constraints */
  IdxConstraint *pTail            /* List of range constraints */
){
  const char *zTbl = pScan->pTab->zName;
  sqlite3_stmt *pIdxList = 0;
  IdxConstraint *pIter;
  int nEq = 0;                    /* Number of elements in pEq */
  int rc;

  /* Count the elements in list pEq */
  for(pIter=pEq; pIter; pIter=pIter->pLink) nEq++;

  rc = idxPrintfPrepareStmt(dbm, &pIdxList, 0, "PRAGMA index_list=%Q", zTbl);
  while( rc==SQLITE_OK && sqlite3_step(pIdxList)==SQLITE_ROW ){
    int bMatch = 1;
    IdxConstraint *pT = pTail;
    sqlite3_stmt *pInfo = 0;
    const char *zIdx = (const char*)sqlite3_column_text(pIdxList, 1);

    /* Zero the IdxConstraint.bFlag values in the pEq list */
    for(pIter=pEq; pIter; pIter=pIter->pLink) pIter->bFlag = 0;

    rc = idxPrintfPrepareStmt(dbm, &pInfo, 0, "PRAGMA index_xInfo=%Q", zIdx);
    while( rc==SQLITE_OK && sqlite3_step(pInfo)==SQLITE_ROW ){
      int iIdx = sqlite3_column_int(pInfo, 0);
      int iCol = sqlite3_column_int(pInfo, 1);
      const char *zColl = (const char*)sqlite3_column_text(pInfo, 4);

      if( iIdx<nEq ){
        for(pIter=pEq; pIter; pIter=pIter->pLink){
          if( pIter->bFlag ) continue;
          if( pIter->iCol!=iCol ) continue;
          if( sqlite3_stricmp(pIter->zColl, zColl) ) continue;
          pIter->bFlag = 1;
          break;
        }
        if( pIter==0 ){
          bMatch = 0;
          break;
        }
      }else{
        if( pT ){
          if( pT->iCol!=iCol || sqlite3_stricmp(pT->zColl, zColl) ){
            bMatch = 0;
            break;
          }
          pT = pT->pLink;
        }
      }
    }
    idxFinalize(&rc, pInfo);

    if( rc==SQLITE_OK && bMatch ){
      sqlite3_finalize(pIdxList);
      return 1;
    }
  }
  idxFinalize(&rc, pIdxList);

  *pRc = rc;
  return 0;
}

static int idxCreateFromCons(
  sqlite3expert *p,
  IdxScan *pScan,
  IdxConstraint *pEq, 
  IdxConstraint *pTail
){
  sqlite3 *dbm = p->dbm;
  int rc = SQLITE_OK;
  if( (pEq || pTail) && 0==idxFindCompatible(&rc, dbm, pScan, pEq, pTail) ){
    IdxTable *pTab = pScan->pTab;
    char *zCols = 0;
    char *zIdx = 0;
    IdxConstraint *pCons;
    int h = 0;
    const char *zFmt;

    for(pCons=pEq; pCons; pCons=pCons->pLink){
      zCols = idxAppendColDefn(&rc, zCols, pTab, pCons);
    }
    for(pCons=pTail; pCons; pCons=pCons->pLink){
      zCols = idxAppendColDefn(&rc, zCols, pTab, pCons);
    }

    if( rc==SQLITE_OK ){
      /* Hash the list of columns to come up with a name for the index */
      const char *zTable = pScan->pTab->zName;
      char *zName;                /* Index name */
      int i;
      for(i=0; zCols[i]; i++){
        h += ((h<<3) + zCols[i]);
      }
      zName = sqlite3_mprintf("%s_idx_%08x", zTable, h);
      if( zName==0 ){ 
        rc = SQLITE_NOMEM;
      }else{
        if( idxIdentifierRequiresQuotes(zTable) ){
          zFmt = "CREATE INDEX '%q' ON %Q(%s)";
        }else{
          zFmt = "CREATE INDEX %s ON %s(%s)";
        }
        zIdx = sqlite3_mprintf(zFmt, zName, zTable, zCols);
        if( !zIdx ){
          rc = SQLITE_NOMEM;
        }else{
          rc = sqlite3_exec(dbm, zIdx, 0, 0, p->pzErrmsg);
          idxHashAdd(&rc, &p->hIdx, zName, zIdx);
        }
        sqlite3_free(zName);
        sqlite3_free(zIdx);
      }
    }

    sqlite3_free(zCols);
  }
  return rc;
}

/*
** Return true if list pList (linked by IdxConstraint.pLink) contains
** a constraint compatible with *p. Otherwise return false.
*/
static int idxFindConstraint(IdxConstraint *pList, IdxConstraint *p){
  IdxConstraint *pCmp;
  for(pCmp=pList; pCmp; pCmp=pCmp->pLink){
    if( p->iCol==pCmp->iCol ) return 1;
  }
  return 0;
}

static int idxCreateFromWhere(
  sqlite3expert *p, 
  IdxScan *pScan,                 /* Create indexes for this scan */
  IdxConstraint *pTail            /* range/ORDER BY constraints for inclusion */
){
  IdxConstraint *p1 = 0;
  IdxConstraint *pCon;
  int rc;

  /* Gather up all the == constraints. */
  for(pCon=pScan->pEq; pCon; pCon=pCon->pNext){
    if( !idxFindConstraint(p1, pCon) && !idxFindConstraint(pTail, pCon) ){
      pCon->pLink = p1;
      p1 = pCon;
    }
  }

  /* Create an index using the == constraints collected above. And the
  ** range constraint/ORDER BY terms passed in by the caller, if any. */
  rc = idxCreateFromCons(p, pScan, p1, pTail);

  /* If no range/ORDER BY passed by the caller, create a version of the
  ** index for each range constraint.  */
  if( pTail==0 ){
    for(pCon=pScan->pRange; rc==SQLITE_OK && pCon; pCon=pCon->pNext){
      assert( pCon->pLink==0 );
      if( !idxFindConstraint(p1, pCon) && !idxFindConstraint(pTail, pCon) ){
        rc = idxCreateFromCons(p, pScan, p1, pCon);
      }
    }
  }

  return rc;
}

/*
** Create candidate indexes in database [dbm] based on the data in 
** linked-list pScan.
*/
static int idxCreateCandidates(sqlite3expert *p, char **pzErr){
  int rc = SQLITE_OK;
  IdxScan *pIter;

  for(pIter=p->pScan; pIter && rc==SQLITE_OK; pIter=pIter->pNextScan){
    rc = idxCreateFromWhere(p, pIter, 0);
    if( rc==SQLITE_OK && pIter->pOrder ){
      rc = idxCreateFromWhere(p, pIter, pIter->pOrder);
    }
  }

  return rc;
}

/*
** Free all elements of the linked list starting at pConstraint.
*/
static void idxConstraintFree(IdxConstraint *pConstraint){
  IdxConstraint *pNext;
  IdxConstraint *p;

  for(p=pConstraint; p; p=pNext){
    pNext = p->pNext;
    sqlite3_free(p);
  }
}

/*
** Free all elements of the linked list starting from pScan up until pLast
** (pLast is not freed).
*/
static void idxScanFree(IdxScan *pScan, IdxScan *pLast){
  IdxScan *p;
  IdxScan *pNext;
  for(p=pScan; p!=pLast; p=pNext){
    pNext = p->pNextScan;
    idxConstraintFree(p->pOrder);
    idxConstraintFree(p->pEq);
    idxConstraintFree(p->pRange);
    sqlite3_free(p);
  }
}

/*
** Free all elements of the linked list starting from pStatement up 
** until pLast (pLast is not freed).
*/
static void idxStatementFree(IdxStatement *pStatement, IdxStatement *pLast){
  IdxStatement *p;
  IdxStatement *pNext;
  for(p=pStatement; p!=pLast; p=pNext){
    pNext = p->pNext;
    sqlite3_free(p->zEQP);
    sqlite3_free(p->zIdx);
    sqlite3_free(p);
  }
}

/*
** Free the linked list of IdxTable objects starting at pTab.
*/
static void idxTableFree(IdxTable *pTab){
  IdxTable *pIter;
  IdxTable *pNext;
  for(pIter=pTab; pIter; pIter=pNext){
    pNext = pIter->pNext;
    sqlite3_free(pIter);
  }
}

/*
** Free the linked list of IdxWrite objects starting at pTab.
*/
static void idxWriteFree(IdxWrite *pTab){
  IdxWrite *pIter;
  IdxWrite *pNext;
  for(pIter=pTab; pIter; pIter=pNext){
    pNext = pIter->pNext;
    sqlite3_free(pIter);
  }
}



/*
** This function is called after candidate indexes have been created. It
** runs all the queries to see which indexes they prefer, and populates
** IdxStatement.zIdx and IdxStatement.zEQP with the results.
*/
int idxFindIndexes(
  sqlite3expert *p,
  char **pzErr                         /* OUT: Error message (sqlite3_malloc) */
){
  IdxStatement *pStmt;
  sqlite3 *dbm = p->dbm;
  int rc = SQLITE_OK;

  IdxHash hIdx;
  idxHashInit(&hIdx);

  for(pStmt=p->pStatement; rc==SQLITE_OK && pStmt; pStmt=pStmt->pNext){
    IdxHashEntry *pEntry;
    sqlite3_stmt *pExplain = 0;
    idxHashClear(&hIdx);
    rc = idxPrintfPrepareStmt(dbm, &pExplain, pzErr,
        "EXPLAIN QUERY PLAN %s", pStmt->zSql
    );
    while( rc==SQLITE_OK && sqlite3_step(pExplain)==SQLITE_ROW ){
      int iSelectid = sqlite3_column_int(pExplain, 0);
      int iOrder = sqlite3_column_int(pExplain, 1);
      int iFrom = sqlite3_column_int(pExplain, 2);
      const char *zDetail = (const char*)sqlite3_column_text(pExplain, 3);
      int nDetail = STRLEN(zDetail);
      int i;

      for(i=0; i<nDetail; i++){
        const char *zIdx = 0;
        if( memcmp(&zDetail[i], " USING INDEX ", 13)==0 ){
          zIdx = &zDetail[i+13];
        }else if( memcmp(&zDetail[i], " USING COVERING INDEX ", 22)==0 ){
          zIdx = &zDetail[i+22];
        }
        if( zIdx ){
          const char *zSql;
          int nIdx = 0;
          while( zIdx[nIdx]!='\0' && (zIdx[nIdx]!=' ' || zIdx[nIdx+1]!='(') ){
            nIdx++;
          }
          zSql = idxHashSearch(&p->hIdx, zIdx, nIdx);
          if( zSql ){
            idxHashAdd(&rc, &hIdx, zSql, 0);
            if( rc ) goto find_indexes_out;
          }
          break;
        }
      }

      pStmt->zEQP = idxAppendText(&rc, pStmt->zEQP, "%d|%d|%d|%s\n", 
          iSelectid, iOrder, iFrom, zDetail
      );
    }

    for(pEntry=hIdx.pFirst; pEntry; pEntry=pEntry->pNext){
      pStmt->zIdx = idxAppendText(&rc, pStmt->zIdx, "%s;\n", pEntry->zKey);
    }

    idxFinalize(&rc, pExplain);
  }

 find_indexes_out:
  idxHashClear(&hIdx);
  return rc;
}

static int idxAuthCallback(
  void *pCtx,
  int eOp,
  const char *z3,
  const char *z4,
  const char *zDb,
  const char *zTrigger
){
  int rc = SQLITE_OK;
  if( eOp==SQLITE_INSERT || eOp==SQLITE_UPDATE || eOp==SQLITE_DELETE ){
    if( sqlite3_stricmp(zDb, "main")==0 ){
      sqlite3expert *p = (sqlite3expert*)pCtx;
      IdxTable *pTab;
      for(pTab=p->pTable; pTab; pTab=pTab->pNext){
        if( 0==sqlite3_stricmp(z3, pTab->zName) ) break;
      }
      if( pTab ){
        IdxWrite *pWrite;
        for(pWrite=p->pWrite; pWrite; pWrite=pWrite->pNext){
          if( pWrite->pTab==pTab && pWrite->eOp==eOp ) break;
        }
        if( pWrite==0 ){
          pWrite = idxMalloc(&rc, sizeof(IdxWrite));
          if( rc==SQLITE_OK ){
            pWrite->pTab = pTab;
            pWrite->eOp = eOp;
            pWrite->pNext = p->pWrite;
            p->pWrite = pWrite;
          }
        }
      }
    }
  }
  return rc;
}

static int idxProcessOneTrigger(
  sqlite3expert *p, 
  IdxWrite *pWrite, 
  char **pzErr
){
  static const char *zInt = UNIQUE_TABLE_NAME;
  static const char *zDrop = "DROP TABLE " UNIQUE_TABLE_NAME;
  IdxTable *pTab = pWrite->pTab;
  const char *zTab = pTab->zName;
  const char *zSql = 
    "SELECT 'CREATE TEMP' || substr(sql, 7) FROM sqlite_master "
    "WHERE tbl_name = %Q AND type IN ('table', 'trigger') "
    "ORDER BY type;";
  sqlite3_stmt *pSelect = 0;
  int rc = SQLITE_OK;
  char *zWrite = 0;

  /* Create the table and its triggers in the temp schema */
  rc = idxPrintfPrepareStmt(p->db, &pSelect, pzErr, zSql, zTab, zTab);
  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pSelect) ){
    const char *zCreate = (const char*)sqlite3_column_text(pSelect, 0);
    rc = sqlite3_exec(p->dbv, zCreate, 0, 0, pzErr);
  }
  idxFinalize(&rc, pSelect);

  /* Rename the table in the temp schema to zInt */
  if( rc==SQLITE_OK ){
    char *z = sqlite3_mprintf("ALTER TABLE temp.%Q RENAME TO %Q", zTab, zInt);
    if( z==0 ){
      rc = SQLITE_NOMEM;
    }else{
      rc = sqlite3_exec(p->dbv, z, 0, 0, pzErr);
      sqlite3_free(z);
    }
  }

  switch( pWrite->eOp ){
    case SQLITE_INSERT: {
      int i;
      zWrite = idxAppendText(&rc, zWrite, "INSERT INTO %Q VALUES(", zInt);
      for(i=0; i<pTab->nCol; i++){
        zWrite = idxAppendText(&rc, zWrite, "%s?", i==0 ? "" : ", ");
      }
      zWrite = idxAppendText(&rc, zWrite, ")");
      break;
    }
    case SQLITE_UPDATE: {
      int i;
      zWrite = idxAppendText(&rc, zWrite, "UPDATE %Q SET ", zInt);
      for(i=0; i<pTab->nCol; i++){
        zWrite = idxAppendText(&rc, zWrite, "%s%Q=?", i==0 ? "" : ", ", 
            pTab->aCol[i].zName
        );
      }
      break;
    }
    default: {
      assert( pWrite->eOp==SQLITE_DELETE );
      if( rc==SQLITE_OK ){
        zWrite = sqlite3_mprintf("DELETE FROM %Q", zInt);
        if( zWrite==0 ) rc = SQLITE_NOMEM;
      }
    }
  }

  if( rc==SQLITE_OK ){
    sqlite3_stmt *pX = 0;
    rc = sqlite3_prepare_v2(p->dbv, zWrite, -1, &pX, 0);
    idxFinalize(&rc, pX);
    if( rc!=SQLITE_OK ){
      idxDatabaseError(p->dbv, pzErr);
    }
  }
  sqlite3_free(zWrite);

  if( rc==SQLITE_OK ){
    rc = sqlite3_exec(p->dbv, zDrop, 0, 0, pzErr);
  }

  return rc;
}

static int idxProcessTriggers(sqlite3expert *p, char **pzErr){
  int rc = SQLITE_OK;
  IdxWrite *pEnd = 0;
  IdxWrite *pFirst = p->pWrite;

  while( rc==SQLITE_OK && pFirst!=pEnd ){
    IdxWrite *pIter;
    for(pIter=pFirst; rc==SQLITE_OK && pIter!=pEnd; pIter=pIter->pNext){
      rc = idxProcessOneTrigger(p, pIter, pzErr);
    }
    pEnd = pFirst;
    pFirst = p->pWrite;
  }

  return rc;
}


static int idxCreateVtabSchema(sqlite3expert *p, char **pzErrmsg){
  int rc = idxRegisterVtab(p);
  sqlite3_stmt *pSchema = 0;

  /* For each table in the main db schema:
  **
  **   1) Add an entry to the p->pTable list, and
  **   2) Create the equivalent virtual table in dbv.
  */
  rc = idxPrepareStmt(p->db, &pSchema, pzErrmsg,
      "SELECT type, name, sql, 1 FROM sqlite_master "
      "WHERE type IN ('table','view') AND name NOT LIKE 'sqlite_%%' "
      " UNION ALL "
      "SELECT type, name, sql, 2 FROM sqlite_master "
      "WHERE type = 'trigger'"
      "  AND tbl_name IN(SELECT name FROM sqlite_master WHERE type = 'view') "
      "ORDER BY 4, 1"
  );
  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pSchema) ){
    const char *zType = (const char*)sqlite3_column_text(pSchema, 0);
    const char *zName = (const char*)sqlite3_column_text(pSchema, 1);
    const char *zSql = (const char*)sqlite3_column_text(pSchema, 2);

    if( zType[0]=='v' || zType[1]=='r' ){
      rc = sqlite3_exec(p->dbv, zSql, 0, 0, pzErrmsg);
    }else{
      IdxTable *pTab;
      rc = idxGetTableInfo(p->db, zName, &pTab, pzErrmsg);
      if( rc==SQLITE_OK ){
        int i;
        char *zInner = 0;
        char *zOuter = 0;
        pTab->pNext = p->pTable;
        p->pTable = pTab;

        /* The statement the vtab will pass to sqlite3_declare_vtab() */
        zInner = idxAppendText(&rc, 0, "CREATE TABLE x(");
        for(i=0; i<pTab->nCol; i++){
          zInner = idxAppendText(&rc, zInner, "%s%Q COLLATE %s", 
              (i==0 ? "" : ", "), pTab->aCol[i].zName, pTab->aCol[i].zColl
          );
        }
        zInner = idxAppendText(&rc, zInner, ")");

        /* The CVT statement to create the vtab */
        zOuter = idxAppendText(&rc, 0, 
            "CREATE VIRTUAL TABLE %Q USING expert(%Q)", zName, zInner
        );
        if( rc==SQLITE_OK ){
          rc = sqlite3_exec(p->dbv, zOuter, 0, 0, pzErrmsg);
        }
        sqlite3_free(zInner);
        sqlite3_free(zOuter);
      }
    }
  }
  idxFinalize(&rc, pSchema);
  return rc;
}

struct IdxSampleCtx {
  int iTarget;
  double target;                  /* Target nRet/nRow value */
  double nRow;                    /* Number of rows seen */
  double nRet;                    /* Number of rows returned */
};

static void idxSampleFunc(
  sqlite3_context *pCtx,
  int argc,
  sqlite3_value **argv
){
  struct IdxSampleCtx *p = (struct IdxSampleCtx*)sqlite3_user_data(pCtx);
  int bRet;

  assert( argc==0 );
  if( p->nRow==0.0 ){
    bRet = 1;
  }else{
    bRet = (p->nRet / p->nRow) <= p->target;
    if( bRet==0 ){
      unsigned short rnd;
      sqlite3_randomness(2, (void*)&rnd);
      bRet = ((int)rnd % 100) <= p->iTarget;
    }
  }

  sqlite3_result_int(pCtx, bRet);
  p->nRow += 1.0;
  p->nRet += (double)bRet;
}

struct IdxRemCtx {
  int nSlot;
  struct IdxRemSlot {
    int eType;                    /* SQLITE_NULL, INTEGER, REAL, TEXT, BLOB */
    i64 iVal;                     /* SQLITE_INTEGER value */
    double rVal;                  /* SQLITE_FLOAT value */
    int nByte;                    /* Bytes of space allocated at z */
    int n;                        /* Size of buffer z */
    char *z;                      /* SQLITE_TEXT/BLOB value */
  } aSlot[1];
};

/*
** Implementation of scalar function rem().
*/
static void idxRemFunc(
  sqlite3_context *pCtx,
  int argc,
  sqlite3_value **argv
){
  struct IdxRemCtx *p = (struct IdxRemCtx*)sqlite3_user_data(pCtx);
  struct IdxRemSlot *pSlot;
  int iSlot;
  assert( argc==2 );

  iSlot = sqlite3_value_int(argv[0]);
  assert( iSlot<=p->nSlot );
  pSlot = &p->aSlot[iSlot];

  switch( pSlot->eType ){
    case SQLITE_NULL:
      /* no-op */
      break;

    case SQLITE_INTEGER:
      sqlite3_result_int64(pCtx, pSlot->iVal);
      break;

    case SQLITE_FLOAT:
      sqlite3_result_double(pCtx, pSlot->rVal);
      break;

    case SQLITE_BLOB:
      sqlite3_result_blob(pCtx, pSlot->z, pSlot->n, SQLITE_TRANSIENT);
      break;

    case SQLITE_TEXT:
      sqlite3_result_text(pCtx, pSlot->z, pSlot->n, SQLITE_TRANSIENT);
      break;
  }

  pSlot->eType = sqlite3_value_type(argv[1]);
  switch( pSlot->eType ){
    case SQLITE_NULL:
      /* no-op */
      break;

    case SQLITE_INTEGER:
      pSlot->iVal = sqlite3_value_int64(argv[1]);
      break;

    case SQLITE_FLOAT:
      pSlot->rVal = sqlite3_value_double(argv[1]);
      break;

    case SQLITE_BLOB:
    case SQLITE_TEXT: {
      int nByte = sqlite3_value_bytes(argv[1]);
      if( nByte>pSlot->nByte ){
        char *zNew = (char*)sqlite3_realloc(pSlot->z, nByte*2);
        if( zNew==0 ){
          sqlite3_result_error_nomem(pCtx);
          return;
        }
        pSlot->nByte = nByte*2;
        pSlot->z = zNew;
      }
      pSlot->n = nByte;
      if( pSlot->eType==SQLITE_BLOB ){
        memcpy(pSlot->z, sqlite3_value_blob(argv[1]), nByte);
      }else{
        memcpy(pSlot->z, sqlite3_value_text(argv[1]), nByte);
      }
      break;
    }
  }
}

static int idxLargestIndex(sqlite3 *db, int *pnMax, char **pzErr){
  int rc = SQLITE_OK;
  const char *zMax = 
    "SELECT max(i.seqno) FROM "
    "  sqlite_master AS s, "
    "  pragma_index_list(s.name) AS l, "
    "  pragma_index_info(l.name) AS i "
    "WHERE s.type = 'table'";
  sqlite3_stmt *pMax = 0;

  *pnMax = 0;
  rc = idxPrepareStmt(db, &pMax, pzErr, zMax);
  if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pMax) ){
    *pnMax = sqlite3_column_int(pMax, 0) + 1;
  }
  idxFinalize(&rc, pMax);

  return rc;
}

static int idxPopulateOneStat1(
  sqlite3expert *p,
  sqlite3_stmt *pIndexXInfo,
  sqlite3_stmt *pWriteStat,
  const char *zTab,
  const char *zIdx,
  char **pzErr
){
  char *zCols = 0;
  char *zOrder = 0;
  char *zQuery = 0;
  int nCol = 0;
  int i;
  sqlite3_stmt *pQuery = 0;
  int *aStat = 0;
  int rc = SQLITE_OK;

  assert( p->iSample>0 );

  /* Formulate the query text */
  sqlite3_bind_text(pIndexXInfo, 1, zIdx, -1, SQLITE_STATIC);
  while( SQLITE_OK==rc && SQLITE_ROW==sqlite3_step(pIndexXInfo) ){
    const char *zComma = zCols==0 ? "" : ", ";
    const char *zName = (const char*)sqlite3_column_text(pIndexXInfo, 0);
    const char *zColl = (const char*)sqlite3_column_text(pIndexXInfo, 1);
    zCols = idxAppendText(&rc, zCols, 
        "%sx.%Q IS rem(%d, x.%Q) COLLATE %s", zComma, zName, nCol, zName, zColl
    );
    zOrder = idxAppendText(&rc, zOrder, "%s%d", zComma, ++nCol);
  }
  if( rc==SQLITE_OK ){
    if( p->iSample==100 ){
      zQuery = sqlite3_mprintf(
          "SELECT %s FROM %Q x ORDER BY %s", zCols, zTab, zOrder
      );
    }else{
      zQuery = sqlite3_mprintf(
          "SELECT %s FROM temp."UNIQUE_TABLE_NAME" x ORDER BY %s", zCols, zOrder
      );
    }
  }
  sqlite3_free(zCols);
  sqlite3_free(zOrder);

  /* Formulate the query text */
  if( rc==SQLITE_OK ){
    sqlite3 *dbrem = (p->iSample==100 ? p->db : p->dbv);
    rc = idxPrepareStmt(dbrem, &pQuery, pzErr, zQuery);
  }
  sqlite3_free(zQuery);

  if( rc==SQLITE_OK ){
    aStat = (int*)idxMalloc(&rc, sizeof(int)*(nCol+1));
  }
  if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pQuery) ){
    IdxHashEntry *pEntry;
    char *zStat = 0;
    for(i=0; i<=nCol; i++) aStat[i] = 1;
    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pQuery) ){
      aStat[0]++;
      for(i=0; i<nCol; i++){
        if( sqlite3_column_int(pQuery, i)==0 ) break;
      }
      for(/*no-op*/; i<nCol; i++){
        aStat[i+1]++;
      }
    }

    if( rc==SQLITE_OK ){
      int s0 = aStat[0];
      zStat = sqlite3_mprintf("%d", s0);
      if( zStat==0 ) rc = SQLITE_NOMEM;
      for(i=1; rc==SQLITE_OK && i<=nCol; i++){
        zStat = idxAppendText(&rc, zStat, " %d", (s0+aStat[i]/2) / aStat[i]);
      }
    }

    if( rc==SQLITE_OK ){
      sqlite3_bind_text(pWriteStat, 1, zTab, -1, SQLITE_STATIC);
      sqlite3_bind_text(pWriteStat, 2, zIdx, -1, SQLITE_STATIC);
      sqlite3_bind_text(pWriteStat, 3, zStat, -1, SQLITE_STATIC);
      sqlite3_step(pWriteStat);
      rc = sqlite3_reset(pWriteStat);
    }

    pEntry = idxHashFind(&p->hIdx, zIdx, STRLEN(zIdx));
    if( pEntry ){
      assert( pEntry->zVal2==0 );
      pEntry->zVal2 = zStat;
    }else{
      sqlite3_free(zStat);
    }
  }
  sqlite3_free(aStat);
  idxFinalize(&rc, pQuery);

  return rc;
}

static int idxBuildSampleTable(sqlite3expert *p, const char *zTab){
  int rc;
  char *zSql;

  rc = sqlite3_exec(p->dbv,"DROP TABLE IF EXISTS temp."UNIQUE_TABLE_NAME,0,0,0);
  if( rc!=SQLITE_OK ) return rc;

  zSql = sqlite3_mprintf(
      "CREATE TABLE temp." UNIQUE_TABLE_NAME " AS SELECT * FROM %Q", zTab
  );
  if( zSql==0 ) return SQLITE_NOMEM;
  rc = sqlite3_exec(p->dbv, zSql, 0, 0, 0);
  sqlite3_free(zSql);

  return rc;
}

/*
** This function is called as part of sqlite3_expert_analyze(). Candidate
** indexes have already been created in database sqlite3expert.dbm, this
** function populates sqlite_stat1 table in the same database.
**
** The stat1 data is generated by querying the 
*/
static int idxPopulateStat1(sqlite3expert *p, char **pzErr){
  int rc = SQLITE_OK;
  int nMax =0;
  struct IdxRemCtx *pCtx = 0;
  struct IdxSampleCtx samplectx; 
  int i;
  i64 iPrev = -100000;
  sqlite3_stmt *pAllIndex = 0;
  sqlite3_stmt *pIndexXInfo = 0;
  sqlite3_stmt *pWrite = 0;

  const char *zAllIndex =
    "SELECT s.rowid, s.name, l.name FROM "
    "  sqlite_master AS s, "
    "  pragma_index_list(s.name) AS l "
    "WHERE s.type = 'table'";
  const char *zIndexXInfo = 
    "SELECT name, coll FROM pragma_index_xinfo(?) WHERE key";
  const char *zWrite = "INSERT INTO sqlite_stat1 VALUES(?, ?, ?)";

  /* If iSample==0, no sqlite_stat1 data is required. */
  if( p->iSample==0 ) return SQLITE_OK;

  rc = idxLargestIndex(p->dbm, &nMax, pzErr);
  if( nMax<=0 || rc!=SQLITE_OK ) return rc;

  rc = sqlite3_exec(p->dbm, "ANALYZE; PRAGMA writable_schema=1", 0, 0, 0);

  if( rc==SQLITE_OK ){
    int nByte = sizeof(struct IdxRemCtx) + (sizeof(struct IdxRemSlot) * nMax);
    pCtx = (struct IdxRemCtx*)idxMalloc(&rc, nByte);
  }

  if( rc==SQLITE_OK ){
    sqlite3 *dbrem = (p->iSample==100 ? p->db : p->dbv);
    rc = sqlite3_create_function(
        dbrem, "rem", 2, SQLITE_UTF8, (void*)pCtx, idxRemFunc, 0, 0
    );
  }
  if( rc==SQLITE_OK ){
    rc = sqlite3_create_function(
        p->db, "sample", 0, SQLITE_UTF8, (void*)&samplectx, idxSampleFunc, 0, 0
    );
  }

  if( rc==SQLITE_OK ){
    pCtx->nSlot = nMax+1;
    rc = idxPrepareStmt(p->dbm, &pAllIndex, pzErr, zAllIndex);
  }
  if( rc==SQLITE_OK ){
    rc = idxPrepareStmt(p->dbm, &pIndexXInfo, pzErr, zIndexXInfo);
  }
  if( rc==SQLITE_OK ){
    rc = idxPrepareStmt(p->dbm, &pWrite, pzErr, zWrite);
  }

  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pAllIndex) ){
    i64 iRowid = sqlite3_column_int64(pAllIndex, 0);
    const char *zTab = (const char*)sqlite3_column_text(pAllIndex, 1);
    const char *zIdx = (const char*)sqlite3_column_text(pAllIndex, 2);
    if( p->iSample<100 && iPrev!=iRowid ){
      samplectx.target = (double)p->iSample / 100.0;
      samplectx.iTarget = p->iSample;
      samplectx.nRow = 0.0;
      samplectx.nRet = 0.0;
      rc = idxBuildSampleTable(p, zTab);
      if( rc!=SQLITE_OK ) break;
    }
    rc = idxPopulateOneStat1(p, pIndexXInfo, pWrite, zTab, zIdx, pzErr);
    iPrev = iRowid;
  }
  if( rc==SQLITE_OK && p->iSample<100 ){
    rc = sqlite3_exec(p->dbv, 
        "DROP TABLE IF EXISTS temp." UNIQUE_TABLE_NAME, 0,0,0
    );
  }

  idxFinalize(&rc, pAllIndex);
  idxFinalize(&rc, pIndexXInfo);
  idxFinalize(&rc, pWrite);

  for(i=0; i<pCtx->nSlot; i++){
    sqlite3_free(pCtx->aSlot[i].z);
  }
  sqlite3_free(pCtx);

  if( rc==SQLITE_OK ){
    rc = sqlite3_exec(p->dbm, "ANALYZE sqlite_master", 0, 0, 0);
  }

  sqlite3_exec(p->db, "DROP TABLE IF EXISTS temp."UNIQUE_TABLE_NAME,0,0,0);
  return rc;
}

/*
** Allocate a new sqlite3expert object.
*/
sqlite3expert *sqlite3_expert_new(sqlite3 *db, char **pzErrmsg){
  int rc = SQLITE_OK;
  sqlite3expert *pNew;

  pNew = (sqlite3expert*)idxMalloc(&rc, sizeof(sqlite3expert));

  /* Open two in-memory databases to work with. The "vtab database" (dbv)
  ** will contain a virtual table corresponding to each real table in
  ** the user database schema, and a copy of each view. It is used to
  ** collect information regarding the WHERE, ORDER BY and other clauses
  ** of the user's query.
  */
  if( rc==SQLITE_OK ){
    pNew->db = db;
    pNew->iSample = 100;
    rc = sqlite3_open(":memory:", &pNew->dbv);
  }
  if( rc==SQLITE_OK ){
    rc = sqlite3_open(":memory:", &pNew->dbm);
    if( rc==SQLITE_OK ){
      sqlite3_db_config(pNew->dbm, SQLITE_DBCONFIG_TRIGGER_EQP, 1, (int*)0);
    }
  }
  

  /* Copy the entire schema of database [db] into [dbm]. */
  if( rc==SQLITE_OK ){
    sqlite3_stmt *pSql;
    rc = idxPrintfPrepareStmt(pNew->db, &pSql, pzErrmsg, 
        "SELECT sql FROM sqlite_master WHERE name NOT LIKE 'sqlite_%%'"
        " AND sql NOT LIKE 'CREATE VIRTUAL %%'"
    );
    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pSql) ){
      const char *zSql = (const char*)sqlite3_column_text(pSql, 0);
      rc = sqlite3_exec(pNew->dbm, zSql, 0, 0, pzErrmsg);
    }
    idxFinalize(&rc, pSql);
  }

  /* Create the vtab schema */
  if( rc==SQLITE_OK ){
    rc = idxCreateVtabSchema(pNew, pzErrmsg);
  }

  /* Register the auth callback with dbv */
  if( rc==SQLITE_OK ){
    sqlite3_set_authorizer(pNew->dbv, idxAuthCallback, (void*)pNew);
  }

  /* If an error has occurred, free the new object and reutrn NULL. Otherwise,
  ** return the new sqlite3expert handle.  */
  if( rc!=SQLITE_OK ){
    sqlite3_expert_destroy(pNew);
    pNew = 0;
  }
  return pNew;
}

/*
** Configure an sqlite3expert object.
*/
int sqlite3_expert_config(sqlite3expert *p, int op, ...){
  int rc = SQLITE_OK;
  va_list ap;
  va_start(ap, op);
  switch( op ){
    case EXPERT_CONFIG_SAMPLE: {
      int iVal = va_arg(ap, int);
      if( iVal<0 ) iVal = 0;
      if( iVal>100 ) iVal = 100;
      p->iSample = iVal;
      break;
    }
    default:
      rc = SQLITE_NOTFOUND;
      break;
  }

  va_end(ap);
  return rc;
}

/*
** Add an SQL statement to the analysis.
*/
int sqlite3_expert_sql(
  sqlite3expert *p,               /* From sqlite3_expert_new() */
  const char *zSql,               /* SQL statement to add */
  char **pzErr                    /* OUT: Error message (if any) */
){
  IdxScan *pScanOrig = p->pScan;
  IdxStatement *pStmtOrig = p->pStatement;
  int rc = SQLITE_OK;
  const char *zStmt = zSql;

  if( p->bRun ) return SQLITE_MISUSE;

  while( rc==SQLITE_OK && zStmt && zStmt[0] ){
    sqlite3_stmt *pStmt = 0;
    rc = sqlite3_prepare_v2(p->dbv, zStmt, -1, &pStmt, &zStmt);
    if( rc==SQLITE_OK ){
      if( pStmt ){
        IdxStatement *pNew;
        const char *z = sqlite3_sql(pStmt);
        int n = STRLEN(z);
        pNew = (IdxStatement*)idxMalloc(&rc, sizeof(IdxStatement) + n+1);
        if( rc==SQLITE_OK ){
          pNew->zSql = (char*)&pNew[1];
          memcpy(pNew->zSql, z, n+1);
          pNew->pNext = p->pStatement;
          if( p->pStatement ) pNew->iId = p->pStatement->iId+1;
          p->pStatement = pNew;
        }
        sqlite3_finalize(pStmt);
      }
    }else{
      idxDatabaseError(p->dbv, pzErr);
    }
  }

  if( rc!=SQLITE_OK ){
    idxScanFree(p->pScan, pScanOrig);
    idxStatementFree(p->pStatement, pStmtOrig);
    p->pScan = pScanOrig;
    p->pStatement = pStmtOrig;
  }

  return rc;
}

int sqlite3_expert_analyze(sqlite3expert *p, char **pzErr){
  int rc;
  IdxHashEntry *pEntry;

  /* Do trigger processing to collect any extra IdxScan structures */
  rc = idxProcessTriggers(p, pzErr);

  /* Create candidate indexes within the in-memory database file */
  if( rc==SQLITE_OK ){
    rc = idxCreateCandidates(p, pzErr);
  }

  /* Generate the stat1 data */
  if( rc==SQLITE_OK ){
    rc = idxPopulateStat1(p, pzErr);
  }

  /* Formulate the EXPERT_REPORT_CANDIDATES text */
  for(pEntry=p->hIdx.pFirst; pEntry; pEntry=pEntry->pNext){
    p->zCandidates = idxAppendText(&rc, p->zCandidates, 
        "%s;%s%s\n", pEntry->zVal, 
        pEntry->zVal2 ? " -- stat1: " : "", pEntry->zVal2
    );
  }

  /* Figure out which of the candidate indexes are preferred by the query
  ** planner and report the results to the user.  */
  if( rc==SQLITE_OK ){
    rc = idxFindIndexes(p, pzErr);
  }

  if( rc==SQLITE_OK ){
    p->bRun = 1;
  }
  return rc;
}

/*
** Return the total number of statements that have been added to this
** sqlite3expert using sqlite3_expert_sql().
*/
int sqlite3_expert_count(sqlite3expert *p){
  int nRet = 0;
  if( p->pStatement ) nRet = p->pStatement->iId+1;
  return nRet;
}

/*
** Return a component of the report.
*/
const char *sqlite3_expert_report(sqlite3expert *p, int iStmt, int eReport){
  const char *zRet = 0;
  IdxStatement *pStmt;

  if( p->bRun==0 ) return 0;
  for(pStmt=p->pStatement; pStmt && pStmt->iId!=iStmt; pStmt=pStmt->pNext);
  switch( eReport ){
    case EXPERT_REPORT_SQL:
      if( pStmt ) zRet = pStmt->zSql;
      break;
    case EXPERT_REPORT_INDEXES:
      if( pStmt ) zRet = pStmt->zIdx;
      break;
    case EXPERT_REPORT_PLAN:
      if( pStmt ) zRet = pStmt->zEQP;
      break;
    case EXPERT_REPORT_CANDIDATES:
      zRet = p->zCandidates;
      break;
  }
  return zRet;
}

/*
** Free an sqlite3expert object.
*/
void sqlite3_expert_destroy(sqlite3expert *p){
  if( p ){
    sqlite3_close(p->dbm);
    sqlite3_close(p->dbv);
    idxScanFree(p->pScan, 0);
    idxStatementFree(p->pStatement, 0);
    idxTableFree(p->pTable);
    idxWriteFree(p->pWrite);
    idxHashClear(&p->hIdx);
    sqlite3_free(p->zCandidates);
    sqlite3_free(p);
  }
}

/************************* End ../ext/expert/sqlite3expert.c ********************/

#if defined(SQLITE_ENABLE_SESSION)
/*
** State information for a single open session
*/
typedef struct OpenSession OpenSession;
struct OpenSession {

struct SavedModeInfo {
  int valid;          /* Is there legit data in here? */
  int mode;           /* Mode prior to ".explain on" */
  int showHeader;     /* The ".header" setting prior to ".explain on" */
  int colWidth[100];  /* Column widths prior to ".explain on" */
};

typedef struct ExpertInfo ExpertInfo;
struct ExpertInfo {
  sqlite3expert *pExpert;
  int bVerbose;
};

/*
** State information about the database connection is contained in an
** instance of the following structure.
*/
typedef struct ShellState ShellState;
struct ShellState {
  sqlite3 *db;           /* The database */
  u8 autoExplain;        /* Automatically turn on .explain mode */
  u8 autoEQP;            /* Run EXPLAIN QUERY PLAN prior to seach SQL stmt */
  u8 statsOn;            /* True to display memory stats before each finalize */
  u8 scanstatsOn;        /* True to display scan stats before each finalize */
  u8 openMode;           /* SHELL_OPEN_NORMAL, _APPENDVFS, or _ZIPFILE */
  int outCount;          /* Revert to stdout when reaching zero */
  int cnt;               /* Number of records displayed so far */
  FILE *out;             /* Write results here */
  FILE *traceOut;        /* Output for sqlite3_trace() */
  int nErr;              /* Number of errors seen */
  int mode;              /* An output mode setting */
  int cMode;             /* temporary output mode for the current query */

  int *aiIndent;         /* Array of indents used in MODE_Explain */
  int nIndent;           /* Size of array aiIndent[] */
  int iIndent;           /* Index of current op in aiIndent[] */
#if defined(SQLITE_ENABLE_SESSION)
  int nSession;             /* Number of active sessions */
  OpenSession aSession[4];  /* Array of sessions.  [0] is in focus. */
#endif
  ExpertInfo expert;        /* Valid if previous command was ".expert OPT..." */
};


/* Allowed values for ShellState.autoEQP
*/
#define AUTOEQP_off      0
#define AUTOEQP_on       1
#define AUTOEQP_trigger  2
#define AUTOEQP_full     3

/* Allowed values for ShellState.openMode
*/
#define SHELL_OPEN_UNSPEC     0      /* No open-mode specified */
#define SHELL_OPEN_NORMAL     1      /* Normal database file */
#define SHELL_OPEN_APPENDVFS  2      /* Use appendvfs */
#define SHELL_OPEN_ZIPFILE    3      /* Use the zipfile virtual table */

/*
** These are the allowed shellFlgs values
*/
#define SHFLG_Pagecache      0x00000001 /* The --pagecache option is used */
#define SHFLG_Lookaside      0x00000002 /* Lookaside memory is used */
#define SHFLG_Backslash      0x00000004 /* The --backslash option is used */
#define SHFLG_PreserveRowid  0x00000008 /* .dump preserves rowid values */

static void printSchemaLineN(FILE *out, char *z, int n, const char *zTail){
  char c = z[n];
  z[n] = 0;
  printSchemaLine(out, z, zTail);
  z[n] = c;
}

/*
** Return true if string z[] has nothing but whitespace and comments to the
** end of the first line.
*/
static int wsToEol(const char *z){
  int i;
  for(i=0; z[i]; i++){
    if( z[i]=='\n' ) return 1;
    if( IsSpace(z[i]) ) continue;
    if( z[i]=='-' && z[i+1]=='-' ) return 1;
    return 0;
  }
  return 1;
}
    

/*
** This is the callback routine that the shell
** invokes for each row of a query result.
*/
static int shell_callback(
  void *pArg,
  int nArg,        /* Number of result columns */

          j--;
        }
        z[j++] = c;
      }
      while( j>0 && IsSpace(z[j-1]) ){ j--; }
      z[j] = 0;
      if( strlen30(z)>=79 ){
        for(i=j=0; (c = z[i])!=0; i++){  /* Copy changes from z[i] back to z[j] */
          if( c==cEnd ){
            cEnd = 0;
          }else if( c=='"' || c=='\'' || c=='`' ){
            cEnd = c;
          }else if( c=='[' ){
            cEnd = ']';
          }else if( c=='-' && z[i+1]=='-' ){
            cEnd = '\n';
          }else if( c=='(' ){
            nParen++;
          }else if( c==')' ){
            nParen--;
            if( nLine>0 && nParen==0 && j>0 ){
              printSchemaLineN(p->out, z, j, "\n");
              j = 0;
            }
          }
          z[j++] = c;
          if( nParen==1 && cEnd==0
           && (c=='(' || c=='\n' || (c==',' && !wsToEol(z+i+1)))
          ){
            if( c=='\n' ) j--;
            printSchemaLineN(p->out, z, j, "\n  ");
            j = 0;
            nLine++;
            while( IsSpace(z[i+1]) ){ i++; }
          }
        }

      { "syscw: ",                  "Write() system calls:"     },
      { "read_bytes: ",             "Bytes read from storage:"  },
      { "write_bytes: ",            "Bytes written to storage:" },
      { "cancelled_write_bytes: ",  "Cancelled write bytes:"    },
    };
    int i;
    for(i=0; i<ArraySize(aTrans); i++){
      int n = strlen30(aTrans[i].zPattern);
      if( strncmp(aTrans[i].zPattern, z, n)==0 ){
        utf8_printf(out, "%-36s %s", aTrans[i].zDesc, &z[n]);
        break;
      }
    }
  }
  fclose(in);

    }else{
      do{
        rc = sqlite3_step(pStmt);
      } while( rc == SQLITE_ROW );
    }
  }
}

/*
** This function is called to process SQL if the previous shell command
** was ".expert". It passes the SQL in the second argument directly to
** the sqlite3expert object.
**
** If successful, SQLITE_OK is returned. Otherwise, an SQLite error
** code. In this case, (*pzErr) may be set to point to a buffer containing
** an English language error message. It is the responsibility of the
** caller to eventually free this buffer using sqlite3_free().
*/
static int expertHandleSQL(
  ShellState *pState, 
  const char *zSql, 
  char **pzErr
){
  assert( pState->expert.pExpert );
  assert( pzErr==0 || *pzErr==0 );
  return sqlite3_expert_sql(pState->expert.pExpert, zSql, pzErr);
}

/*
** This function is called either to silently clean up the object
** created by the ".expert" command (if bCancel==1), or to generate a 
** report from it and then clean it up (if bCancel==0).
**
** If successful, SQLITE_OK is returned. Otherwise, an SQLite error
** code. In this case, (*pzErr) may be set to point to a buffer containing
** an English language error message. It is the responsibility of the
** caller to eventually free this buffer using sqlite3_free().
*/
static int expertFinish(
  ShellState *pState,
  int bCancel,
  char **pzErr
){
  int rc = SQLITE_OK;
  sqlite3expert *p = pState->expert.pExpert;
  assert( p );
  assert( bCancel || pzErr==0 || *pzErr==0 );
  if( bCancel==0 ){
    FILE *out = pState->out;
    int bVerbose = pState->expert.bVerbose;

    rc = sqlite3_expert_analyze(p, pzErr);
    if( rc==SQLITE_OK ){
      int nQuery = sqlite3_expert_count(p);
      int i;

      if( bVerbose ){
        const char *zCand = sqlite3_expert_report(p,0,EXPERT_REPORT_CANDIDATES);
        raw_printf(out, "-- Candidates -----------------------------\n");
        raw_printf(out, "%s\n", zCand);
      }
      for(i=0; i<nQuery; i++){
        const char *zSql = sqlite3_expert_report(p, i, EXPERT_REPORT_SQL);
        const char *zIdx = sqlite3_expert_report(p, i, EXPERT_REPORT_INDEXES);
        const char *zEQP = sqlite3_expert_report(p, i, EXPERT_REPORT_PLAN);
        if( zIdx==0 ) zIdx = "(no new indexes)\n";
        if( bVerbose ){
          raw_printf(out, "-- Query %d --------------------------------\n",i+1);
          raw_printf(out, "%s\n\n", zSql);
        }
        raw_printf(out, "%s\n", zIdx);
        raw_printf(out, "%s\n", zEQP);
      }
    }
  }
  sqlite3_expert_destroy(p);
  pState->expert.pExpert = 0;
  return rc;
}


/*
** Execute a statement or set of statements.  Print
** any result rows/columns depending on the current mode
** set via the supplied callback.
**
** This is very similar to SQLite's built-in sqlite3_exec()

  int rc = SQLITE_OK;             /* Return Code */
  int rc2;
  const char *zLeftover;          /* Tail of unprocessed SQL */

  if( pzErrMsg ){
    *pzErrMsg = NULL;
  }

  if( pArg->expert.pExpert ){
    rc = expertHandleSQL(pArg, zSql, pzErrMsg);
    return expertFinish(pArg, (rc!=SQLITE_OK), pzErrMsg);
  }

  while( zSql[0] && (SQLITE_OK == rc) ){
    static const char *zStmtSql;
    rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, &zLeftover);
    if( SQLITE_OK != rc ){
      if( pzErrMsg ){
        *pzErrMsg = save_err_msg(db);

        utf8_printf(pArg->out, "%s\n", zStmtSql ? zStmtSql : zSql);
      }

      /* Show the EXPLAIN QUERY PLAN if .eqp is on */
      if( pArg && pArg->autoEQP && sqlite3_strlike("EXPLAIN%",zStmtSql,0)!=0 ){
        sqlite3_stmt *pExplain;
        char *zEQP;
        int triggerEQP = 0;
        disable_debug_trace_modes();
        sqlite3_db_config(db, SQLITE_DBCONFIG_TRIGGER_EQP, -1, &triggerEQP);
        if( pArg->autoEQP>=AUTOEQP_trigger ){
          sqlite3_db_config(db, SQLITE_DBCONFIG_TRIGGER_EQP, 1, 0);
        }
        zEQP = sqlite3_mprintf("EXPLAIN QUERY PLAN %s", zStmtSql);
        rc = sqlite3_prepare_v2(db, zEQP, -1, &pExplain, 0);
        if( rc==SQLITE_OK ){
          while( sqlite3_step(pExplain)==SQLITE_ROW ){
            raw_printf(pArg->out,"--EQP-- %d,",sqlite3_column_int(pExplain, 0));
            raw_printf(pArg->out,"%d,", sqlite3_column_int(pExplain, 1));
            raw_printf(pArg->out,"%d,", sqlite3_column_int(pExplain, 2));
            utf8_printf(pArg->out,"%s\n", sqlite3_column_text(pExplain, 3));
          }
        }
        sqlite3_finalize(pExplain);
        sqlite3_free(zEQP);
        if( pArg->autoEQP>=AUTOEQP_full ){
          /* Also do an EXPLAIN for ".eqp full" mode */
          zEQP = sqlite3_mprintf("EXPLAIN %s", zStmtSql);
          rc = sqlite3_prepare_v2(db, zEQP, -1, &pExplain, 0);
          if( rc==SQLITE_OK ){
            pArg->cMode = MODE_Explain;
            explain_data_prepare(pArg, pExplain);
            exec_prepared_stmt(pArg, pExplain, xCallback);
            explain_data_delete(pArg);
          }
          sqlite3_finalize(pExplain);
          sqlite3_free(zEQP);
        }
        sqlite3_db_config(db, SQLITE_DBCONFIG_TRIGGER_EQP, triggerEQP, 0);
        restore_debug_trace_modes();
      }

      if( pArg ){
        pArg->cMode = pArg->mode;
        if( pArg->autoExplain
         && sqlite3_column_count(pStmt)==8

  return rc;
}

/*
** Text of a help message
*/
static char zHelp[] =
#if defined(SQLITE_HAVE_ZLIB) && !defined(SQLITE_OMIT_VIRTUALTABLE)
  ".archive ...           Manage SQL archives: \".archive --help\" for details\n"
#endif
#ifndef SQLITE_OMIT_AUTHORIZATION
  ".auth ON|OFF           Show authorizer callbacks\n"
#endif
  ".backup ?DB? FILE      Backup DB (default \"main\") to FILE\n"
  ".bail on|off           Stop after hitting an error.  Default OFF\n"
  ".binary on|off         Turn binary output on or off.  Default OFF\n"
  ".cd DIRECTORY          Change the working directory to DIRECTORY\n"
  ".changes on|off        Show number of rows changed by SQL\n"
  ".check GLOB            Fail if output since .testcase does not match\n"
  ".clone NEWDB           Clone data into NEWDB from the existing database\n"
  ".databases             List names and files of attached databases\n"
  ".dbinfo ?DB?           Show status information about the database\n"
  ".dump ?TABLE? ...      Dump the database in an SQL text format\n"
  "                         If TABLE specified, only dump tables matching\n"
  "                         LIKE pattern TABLE.\n"
  ".echo on|off           Turn command echo on or off\n"
  ".eqp on|off|full       Enable or disable automatic EXPLAIN QUERY PLAN\n"
  ".exit                  Exit this program\n"
  ".expert                EXPERIMENTAL. Suggest indexes for specified queries\n"
/* Because explain mode comes on automatically now, the ".explain" mode
** is removed from the help screen.  It is still supported for legacy, however */
/*".explain ?on|off|auto? Turn EXPLAIN output mode on or off or to automatic\n"*/
  ".fullschema ?--indent? Show schema and the content of sqlite_stat tables\n"
  ".headers on|off        Turn display of headers on or off\n"
  ".help                  Show this message\n"
  ".import FILE TABLE     Import data from FILE into TABLE\n"

  int i;
  for(i=0; i<pSession->nFilter; i++){
    if( sqlite3_strglob(pSession->azFilter[i], zTab)==0 ) return 0;
  }
  return 1;
}
#endif

/*
** Try to deduce the type of file for zName based on its content.  Return
** one of the SHELL_OPEN_* constants.
*/
static int deduceDatabaseType(const char *zName){
  FILE *f = fopen(zName, "rb");
  size_t n;
  int rc = SHELL_OPEN_UNSPEC;
  char zBuf[100];
  if( f==0 ) return SHELL_OPEN_NORMAL;
  fseek(f, -25, SEEK_END);
  n = fread(zBuf, 25, 1, f);
  if( n==1 && memcmp(zBuf, "Start-Of-SQLite3-", 17)==0 ){
    rc = SHELL_OPEN_APPENDVFS;
  }else{
    fseek(f, -22, SEEK_END);
    n = fread(zBuf, 22, 1, f);
    if( n==1 && zBuf[0]==0x50 && zBuf[1]==0x4b && zBuf[2]==0x05
       && zBuf[3]==0x06 ){
      rc = SHELL_OPEN_ZIPFILE;
    }
  }
  fclose(f);
  return rc;  
}

/*
** Make sure the database is open.  If it is not, then open it.  If
** the database fails to open, print an error message and exit.
*/
static void open_db(ShellState *p, int keepAlive){
  if( p->db==0 ){
    sqlite3_initialize();
    if( p->openMode==SHELL_OPEN_UNSPEC && access(p->zDbFilename,0)==0 ){
      p->openMode = deduceDatabaseType(p->zDbFilename);
    }
    switch( p->openMode ){
      case SHELL_OPEN_APPENDVFS: {
        sqlite3_open_v2(p->zDbFilename, &p->db, 
           SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE, "apndvfs");
        break;
      }
      case SHELL_OPEN_ZIPFILE: {
        sqlite3_open(":memory:", &p->db);
        break;
      }
      case SHELL_OPEN_UNSPEC:
      case SHELL_OPEN_NORMAL: {
        sqlite3_open(p->zDbFilename, &p->db);
        break;
      }
    }
    globalDb = p->db;
    if( p->db==0 || SQLITE_OK!=sqlite3_errcode(p->db) ){
      utf8_printf(stderr,"Error: unable to open database \"%s\": %s\n",
          p->zDbFilename, sqlite3_errmsg(p->db));
      if( keepAlive ) return;
      exit(1);
    }
#ifndef SQLITE_OMIT_LOAD_EXTENSION
    sqlite3_enable_load_extension(p->db, 1);
#endif
    sqlite3_fileio_init(p->db, 0, 0);
    sqlite3_shathree_init(p->db, 0, 0);
    sqlite3_completion_init(p->db, 0, 0);
#ifdef SQLITE_HAVE_ZLIB
    sqlite3_zipfile_init(p->db, 0, 0);
    sqlite3_sqlar_init(p->db, 0, 0);
#endif
    sqlite3_create_function(p->db, "shell_add_schema", 3, SQLITE_UTF8, 0,
                            shellAddSchemaName, 0, 0);
    sqlite3_create_function(p->db, "shell_module_schema", 1, SQLITE_UTF8, 0,
                            shellModuleSchema, 0, 0);
    if( p->openMode==SHELL_OPEN_ZIPFILE ){
      char *zSql = sqlite3_mprintf(
         "CREATE VIRTUAL TABLE zip USING zipfile(%Q);", p->zDbFilename);
      sqlite3_exec(p->db, zSql, 0, 0, 0);
      sqlite3_free(zSql);
    }
  }
}

#if HAVE_READLINE || HAVE_EDITLINE
/*
** Readline completion callbacks
*/

}

#elif HAVE_LINENOISE
/*
** Linenoise completion callback
*/
static void linenoise_completion(const char *zLine, linenoiseCompletions *lc){
  int nLine = strlen30(zLine);
  int i, iStart;
  sqlite3_stmt *pStmt = 0;
  char *zSql;
  char zBuf[1000];

  if( nLine>sizeof(zBuf)-30 ) return;
  if( zLine[0]=='.' ) return;

  void *pX
){
  FILE *f = (FILE*)pArg;
  UNUSED_PARAMETER(mType);
  UNUSED_PARAMETER(pP);
  if( f ){
    const char *z = (const char*)pX;
    int i = strlen30(z);
    while( i>0 && z[i-1]==';' ){ i--; }
    utf8_printf(f, "%.*s;\n", i, z);
  }
  return 0;
}
#endif
#endif

){
  sqlite3_stmt *pQuery = 0;
  sqlite3_stmt *pInsert = 0;
  char *zQuery = 0;
  char *zInsert = 0;
  int rc;
  int i, j, n;
  int nTable = strlen30(zTable);
  int k = 0;
  int cnt = 0;
  const int spinRate = 10000;

  zQuery = sqlite3_mprintf("SELECT * FROM \"%w\"", zTable);
  rc = sqlite3_prepare_v2(p->db, zQuery, -1, &pQuery, 0);
  if( rc ){
    utf8_printf(stderr, "Error %d: %s on [%s]\n",
            sqlite3_extended_errcode(p->db), sqlite3_errmsg(p->db),
            zQuery);
    goto end_data_xfer;
  }
  n = sqlite3_column_count(pQuery);
  zInsert = sqlite3_malloc64(200 + nTable + n*3);
  if( zInsert==0 ){
    raw_printf(stderr, "out of memory\n");
    goto end_data_xfer;
  }
  sqlite3_snprintf(200+nTable,zInsert,
                   "INSERT OR IGNORE INTO \"%s\" VALUES(?", zTable);
  i = strlen30(zInsert);
  for(j=1; j<n; j++){
    memcpy(zInsert+i, ",?", 2);
    i += 2;
  }
  memcpy(zInsert+i, ");", 3);
  rc = sqlite3_prepare_v2(newDb, zInsert, -1, &pInsert, 0);
  if( rc ){

    "LEFT JOIN pragma_table_info AS p ON (pk-1=seq AND p.arg=f.[table]) "
    "GROUP BY s.name, f.id "
    "ORDER BY (CASE WHEN ? THEN f.[table] ELSE s.name END)"
  ;
  const char *zGlobIPK = "SEARCH TABLE * USING INTEGER PRIMARY KEY (rowid=?)";

  for(i=2; i<nArg; i++){
    int n = strlen30(azArg[i]);
    if( n>1 && sqlite3_strnicmp("-verbose", azArg[i], n)==0 ){
      bVerbose = 1;
    }
    else if( n>1 && sqlite3_strnicmp("-groupbyparent", azArg[i], n)==0 ){
      bGroupByParent = 1;
      zIndent = "    ";
    }

*/
static int lintDotCommand(
  ShellState *pState,             /* Current shell tool state */
  char **azArg,                   /* Array of arguments passed to dot command */
  int nArg                        /* Number of entries in azArg[] */
){
  int n;
  n = (nArg>=2 ? strlen30(azArg[1]) : 0);
  if( n<1 || sqlite3_strnicmp(azArg[1], "fkey-indexes", n) ) goto usage;
  return lintFkeyIndexes(pState, azArg, nArg);

 usage:
  raw_printf(stderr, "Usage %s sub-command ?switches...?\n", azArg[0]);
  raw_printf(stderr, "Where sub-commands are:\n");
  raw_printf(stderr, "    fkey-indexes\n");
  return SQLITE_ERROR;
}

#if !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(SQLITE_HAVE_ZLIB)
/*********************************************************************************
** The ".archive" or ".ar" command.
*/
static void shellPrepare(
  sqlite3 *db, 
  int *pRc, 
  const char *zSql, 
  sqlite3_stmt **ppStmt
){
  *ppStmt = 0;
  if( *pRc==SQLITE_OK ){
    int rc = sqlite3_prepare_v2(db, zSql, -1, ppStmt, 0);
    if( rc!=SQLITE_OK ){
      raw_printf(stderr, "sql error: %s (%d)\n", 
          sqlite3_errmsg(db), sqlite3_errcode(db)
      );
      *pRc = rc;
    }
  }
}

static void shellPreparePrintf(
  sqlite3 *db, 
  int *pRc, 
  sqlite3_stmt **ppStmt,
  const char *zFmt, 
  ...
){
  *ppStmt = 0;
  if( *pRc==SQLITE_OK ){
    va_list ap;
    char *z;
    va_start(ap, zFmt);
    z = sqlite3_vmprintf(zFmt, ap);
    if( z==0 ){
      *pRc = SQLITE_NOMEM;
    }else{
      shellPrepare(db, pRc, z, ppStmt);
      sqlite3_free(z);
    }
  }
}

static void shellFinalize(
  int *pRc, 
  sqlite3_stmt *pStmt
){
  if( pStmt ){
    sqlite3 *db = sqlite3_db_handle(pStmt);
    int rc = sqlite3_finalize(pStmt);
    if( *pRc==SQLITE_OK ){
      if( rc!=SQLITE_OK ){
        raw_printf(stderr, "SQL error: %s\n", sqlite3_errmsg(db));
      }
      *pRc = rc;
    }
  }
}

static void shellReset(
  int *pRc, 
  sqlite3_stmt *pStmt
){
  int rc = sqlite3_reset(pStmt);
  if( *pRc==SQLITE_OK ){
    if( rc!=SQLITE_OK ){
      sqlite3 *db = sqlite3_db_handle(pStmt);
      raw_printf(stderr, "SQL error: %s\n", sqlite3_errmsg(db));
    }
    *pRc = rc;
  }
}
/*
** Structure representing a single ".ar" command.
*/
typedef struct ArCommand ArCommand;
struct ArCommand {
  int eCmd;                       /* An AR_CMD_* value */
  const char *zFile;              /* --file argument, or NULL */
  const char *zDir;               /* --directory argument, or NULL */
  int bVerbose;                   /* True if --verbose */
  int bZip;                       /* True if --zip */
  int nArg;                       /* Number of command arguments */
  char **azArg;                   /* Array of command arguments */
};

/*
** Print a usage message for the .ar command to stderr and return SQLITE_ERROR.
*/
static int arUsage(FILE *f){
  raw_printf(f,
"\n"
"Usage: .ar [OPTION...] [FILE...]\n"
"The .ar command manages sqlar archives.\n"
"\n"
"Examples:\n"
"  .ar -cf archive.sar foo bar    # Create archive.sar from files foo and bar\n"
"  .ar -tf archive.sar            # List members of archive.sar\n"
"  .ar -xvf archive.sar           # Verbosely extract files from archive.sar\n"
"\n"
"Each command line must feature exactly one command option:\n"
"  -c, --create               Create a new archive\n"
"  -u, --update               Update or add files to an existing archive\n"
"  -t, --list                 List contents of archive\n"
"  -x, --extract              Extract files from archive\n"
"\n"
"And zero or more optional options:\n"
"  -v, --verbose              Print each filename as it is processed\n"
"  -f FILE, --file FILE       Operate on archive FILE (default is current db)\n"
"  -C DIR, --directory DIR    Change to directory DIR to read/extract files\n"
"\n"
"See also: http://sqlite.org/cli.html#sqlar_archive_support\n"
"\n"
);
  return SQLITE_ERROR;
}

/*
** Print an error message for the .ar command to stderr and return 
** SQLITE_ERROR.
*/
static int arErrorMsg(const char *zFmt, ...){
  va_list ap;
  char *z;
  va_start(ap, zFmt);
  z = sqlite3_vmprintf(zFmt, ap);
  va_end(ap);
  raw_printf(stderr, "Error: %s (try \".ar --help\")\n", z);
  sqlite3_free(z);
  return SQLITE_ERROR;
}

/*
** Values for ArCommand.eCmd.
*/
#define AR_CMD_CREATE       1
#define AR_CMD_EXTRACT      2
#define AR_CMD_LIST         3
#define AR_CMD_UPDATE       4
#define AR_CMD_HELP         5

/*
** Other (non-command) switches.
*/
#define AR_SWITCH_VERBOSE   6
#define AR_SWITCH_FILE      7
#define AR_SWITCH_DIRECTORY 8
#define AR_SWITCH_ZIP       9

static int arProcessSwitch(ArCommand *pAr, int eSwitch, const char *zArg){
  switch( eSwitch ){
    case AR_CMD_CREATE:
    case AR_CMD_EXTRACT:
    case AR_CMD_LIST:
    case AR_CMD_UPDATE:
    case AR_CMD_HELP:
      if( pAr->eCmd ){
        return arErrorMsg("multiple command options");
      }
      pAr->eCmd = eSwitch;
      break;

    case AR_SWITCH_VERBOSE:
      pAr->bVerbose = 1;
      break;
    case AR_SWITCH_ZIP:
      pAr->bZip = 1;
      break;

    case AR_SWITCH_FILE:
      pAr->zFile = zArg;
      break;
    case AR_SWITCH_DIRECTORY:
      pAr->zDir = zArg;
      break;
  }

  return SQLITE_OK;
}

/*
** Parse the command line for an ".ar" command. The results are written into
** structure (*pAr). SQLITE_OK is returned if the command line is parsed
** successfully, otherwise an error message is written to stderr and 
** SQLITE_ERROR returned.
*/
static int arParseCommand(
  char **azArg,                   /* Array of arguments passed to dot command */
  int nArg,                       /* Number of entries in azArg[] */
  ArCommand *pAr                  /* Populate this object */
){
  struct ArSwitch {
    char cShort;
    const char *zLong;
    int eSwitch;
    int bArg;
  } aSwitch[] = {
    { 'c', "create",    AR_CMD_CREATE, 0 },
    { 'x', "extract",   AR_CMD_EXTRACT, 0 },
    { 't', "list",      AR_CMD_LIST, 0 },
    { 'u', "update",    AR_CMD_UPDATE, 0 },
    { 'h', "help",      AR_CMD_HELP, 0 },
    { 'v', "verbose",   AR_SWITCH_VERBOSE, 0 },
    { 'f', "file",      AR_SWITCH_FILE, 1 },
    { 'C', "directory", AR_SWITCH_DIRECTORY, 1 },
    { 'z', "zip",       AR_SWITCH_ZIP, 0 }
  };
  int nSwitch = sizeof(aSwitch) / sizeof(struct ArSwitch);
  struct ArSwitch *pEnd = &aSwitch[nSwitch];

  if( nArg<=1 ){
    return arUsage(stderr);
  }else{
    char *z = azArg[1];
    memset(pAr, 0, sizeof(ArCommand));

    if( z[0]!='-' ){
      /* Traditional style [tar] invocation */
      int i;
      int iArg = 2;
      for(i=0; z[i]; i++){
        const char *zArg = 0;
        struct ArSwitch *pOpt;
        for(pOpt=&aSwitch[0]; pOpt<pEnd; pOpt++){
          if( z[i]==pOpt->cShort ) break;
        }
        if( pOpt==pEnd ){
          return arErrorMsg("unrecognized option: %c", z[i]);
        }
        if( pOpt->bArg ){
          if( iArg>=nArg ){
            return arErrorMsg("option requires an argument: %c",z[i]);
          }
          zArg = azArg[iArg++];
        }
        if( arProcessSwitch(pAr, pOpt->eSwitch, zArg) ) return SQLITE_ERROR;
      }
      pAr->nArg = nArg-iArg;
      if( pAr->nArg>0 ){
        pAr->azArg = &azArg[iArg];
      }
    }else{
      /* Non-traditional invocation */
      int iArg;
      for(iArg=1; iArg<nArg; iArg++){
        int n;
        z = azArg[iArg];
        if( z[0]!='-' ){
          /* All remaining command line words are command arguments. */
          pAr->azArg = &azArg[iArg];
          pAr->nArg = nArg-iArg;
          break;
        }
        n = strlen30(z);

        if( z[1]!='-' ){
          int i;
          /* One or more short options */
          for(i=1; i<n; i++){
            const char *zArg = 0;
            struct ArSwitch *pOpt;
            for(pOpt=&aSwitch[0]; pOpt<pEnd; pOpt++){
              if( z[i]==pOpt->cShort ) break;
            }
            if( pOpt==pEnd ){
              return arErrorMsg("unrecognized option: %c\n", z[i]);
            }
            if( pOpt->bArg ){
              if( i<(n-1) ){
                zArg = &z[i+1];
                i = n;
              }else{
                if( iArg>=(nArg-1) ){
                  return arErrorMsg("option requires an argument: %c\n",z[i]);
                }
                zArg = azArg[++iArg];
              }
            }
            if( arProcessSwitch(pAr, pOpt->eSwitch, zArg) ) return SQLITE_ERROR;
          }
        }else if( z[2]=='\0' ){
          /* A -- option, indicating that all remaining command line words
          ** are command arguments.  */
          pAr->azArg = &azArg[iArg+1];
          pAr->nArg = nArg-iArg-1;
          break;
        }else{
          /* A long option */
          const char *zArg = 0;             /* Argument for option, if any */
          struct ArSwitch *pMatch = 0;      /* Matching option */
          struct ArSwitch *pOpt;            /* Iterator */
          for(pOpt=&aSwitch[0]; pOpt<pEnd; pOpt++){
            const char *zLong = pOpt->zLong;
            if( (n-2)<=strlen30(zLong) && 0==memcmp(&z[2], zLong, n-2) ){
              if( pMatch ){
                return arErrorMsg("ambiguous option: %s",z);
              }else{
                pMatch = pOpt;
              }
            }
          }

          if( pMatch==0 ){
            return arErrorMsg("unrecognized option: %s", z);
          }
          if( pMatch->bArg ){
            if( iArg>=(nArg-1) ){
              return arErrorMsg("option requires an argument: %s", z);
            }
            zArg = azArg[++iArg];
          }
          if( arProcessSwitch(pAr, pMatch->eSwitch, zArg) ) return SQLITE_ERROR;
        }
      }
    }
  }

  return SQLITE_OK;
}

/*
** This function assumes that all arguments within the ArCommand.azArg[]
** array refer to archive members, as for the --extract or --list commands. 
** It checks that each of them are present. If any specified file is not
** present in the archive, an error is printed to stderr and an error
** code returned. Otherwise, if all specified arguments are present in
** the archive, SQLITE_OK is returned.
**
** This function strips any trailing '/' characters from each argument.
** This is consistent with the way the [tar] command seems to work on
** Linux.
*/
static int arCheckEntries(sqlite3 *db, ArCommand *pAr){
  int rc = SQLITE_OK;
  if( pAr->nArg ){
    int i;
    sqlite3_stmt *pTest = 0;

    shellPreparePrintf(db, &rc, &pTest, "SELECT name FROM %s WHERE name=?1", 
        pAr->bZip ? "zipfile(?2)" : "sqlar"
    );
    if( rc==SQLITE_OK && pAr->bZip ){
      sqlite3_bind_text(pTest, 2, pAr->zFile, -1, SQLITE_TRANSIENT);
    }
    for(i=0; i<pAr->nArg && rc==SQLITE_OK; i++){
      char *z = pAr->azArg[i];
      int n = strlen30(z);
      int bOk = 0;
      while( n>0 && z[n-1]=='/' ) n--;
      z[n] = '\0';
      sqlite3_bind_text(pTest, 1, z, -1, SQLITE_STATIC);
      if( SQLITE_ROW==sqlite3_step(pTest) ){
        bOk = 1;
      }
      shellReset(&rc, pTest);
      if( rc==SQLITE_OK && bOk==0 ){
        raw_printf(stderr, "not found in archive: %s\n", z);
        rc = SQLITE_ERROR;
      }
    }
    shellFinalize(&rc, pTest);
  }

  return rc;
}

/*
** Format a WHERE clause that can be used against the "sqlar" table to
** identify all archive members that match the command arguments held
** in (*pAr). Leave this WHERE clause in (*pzWhere) before returning.
** The caller is responsible for eventually calling sqlite3_free() on
** any non-NULL (*pzWhere) value.
*/
static void arWhereClause(
  int *pRc, 
  ArCommand *pAr, 
  char **pzWhere                  /* OUT: New WHERE clause */
){
  char *zWhere = 0;
  if( *pRc==SQLITE_OK ){
    if( pAr->nArg==0 ){
      zWhere = sqlite3_mprintf("1");
    }else{
      int i;
      const char *zSep = "";
      for(i=0; i<pAr->nArg; i++){
        const char *z = pAr->azArg[i];
        zWhere = sqlite3_mprintf(
            "%z%s name = '%q' OR name BETWEEN '%q/' AND '%q0'", 
            zWhere, zSep, z, z, z
            );
        if( zWhere==0 ){
          *pRc = SQLITE_NOMEM;
          break;
        }
        zSep = " OR ";
      }
    }
  }
  *pzWhere = zWhere;
}

/*
** Argument zMode must point to a buffer at least 11 bytes in size. This
** function populates this buffer with the string interpretation of
** the unix file mode passed as the second argument (e.g. "drwxr-xr-x").
*/
static void shellModeToString(char *zMode, int mode){
  int i;

  /* Magic numbers copied from [man 2 stat] */
  if( mode & 0040000 ){
    zMode[0] = 'd';
  }else if( (mode & 0120000)==0120000 ){
    zMode[0] = 'l';
  }else{
    zMode[0] = '-';
  }

  for(i=0; i<3; i++){
    int m = (mode >> ((2-i)*3));
    char *a = &zMode[1 + i*3];
    a[0] = (m & 0x4) ? 'r' : '-';
    a[1] = (m & 0x2) ? 'w' : '-';
    a[2] = (m & 0x1) ? 'x' : '-';
  }
  zMode[10] = '\0';
}

/*
** Implementation of .ar "lisT" command. 
*/
static int arListCommand(ShellState *p, sqlite3 *db, ArCommand *pAr){
  const char *zSql = "SELECT %s FROM %s WHERE %s"; 
  const char *zTbl = (pAr->bZip ? "zipfile(?)" : "sqlar");
  const char *azCols[] = {
    "name",
    "mode, sz, datetime(mtime, 'unixepoch'), name"
  };

  char *zWhere = 0;
  sqlite3_stmt *pSql = 0;
  int rc;

  rc = arCheckEntries(db, pAr);
  arWhereClause(&rc, pAr, &zWhere);

  shellPreparePrintf(db, &rc, &pSql, zSql, azCols[pAr->bVerbose], zTbl, zWhere);
  if( rc==SQLITE_OK && pAr->bZip ){
    sqlite3_bind_text(pSql, 1, pAr->zFile, -1, SQLITE_TRANSIENT);
  }
  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pSql) ){
    if( pAr->bVerbose ){
      char zMode[11];
      shellModeToString(zMode, sqlite3_column_int(pSql, 0));

      raw_printf(p->out, "%s % 10d  %s  %s\n", zMode,
          sqlite3_column_int(pSql, 1), 
          sqlite3_column_text(pSql, 2),
          sqlite3_column_text(pSql, 3)
      );
    }else{
      raw_printf(p->out, "%s\n", sqlite3_column_text(pSql, 0));
    }
  }

  shellFinalize(&rc, pSql);
  return rc;
}


/*
** Implementation of .ar "eXtract" command. 
*/
static int arExtractCommand(ShellState *p, sqlite3 *db, ArCommand *pAr){
  const char *zSql1 = 
    "SELECT "
    "  :1 || name, "
    "  writefile(?1 || name, %s, mode, mtime) "
    "FROM %s WHERE (%s) AND (data IS NULL OR ?2 = 0)";

  const char *azExtraArg[] = { 
    "sqlar_uncompress(data, sz)",
    "zipfile_uncompress(data, sz, method)"
  };
  const char *azSource[] = {
    "sqlar", "zipfile(?3)"
  };



  sqlite3_stmt *pSql = 0;
  int rc = SQLITE_OK;
  char *zDir = 0;
  char *zWhere = 0;
  int i;

  /* If arguments are specified, check that they actually exist within
  ** the archive before proceeding. And formulate a WHERE clause to
  ** match them.  */
  rc = arCheckEntries(db, pAr);
  arWhereClause(&rc, pAr, &zWhere);

  if( rc==SQLITE_OK ){
    if( pAr->zDir ){
      zDir = sqlite3_mprintf("%s/", pAr->zDir);
    }else{
      zDir = sqlite3_mprintf("");
    }
    if( zDir==0 ) rc = SQLITE_NOMEM;
  }

  shellPreparePrintf(db, &rc, &pSql, zSql1, 
      azExtraArg[pAr->bZip], azSource[pAr->bZip], zWhere
  );

  if( rc==SQLITE_OK ){
    sqlite3_bind_text(pSql, 1, zDir, -1, SQLITE_STATIC);
    if( pAr->bZip ){
      sqlite3_bind_text(pSql, 3, pAr->zFile, -1, SQLITE_STATIC);
    }

    /* Run the SELECT statement twice. The first time, writefile() is called
    ** for all archive members that should be extracted. The second time,
    ** only for the directories. This is because the timestamps for
    ** extracted directories must be reset after they are populated (as
    ** populating them changes the timestamp).  */
    for(i=0; i<2; i++){
      sqlite3_bind_int(pSql, 2, i);
      while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pSql) ){
        if( i==0 && pAr->bVerbose ){
          raw_printf(p->out, "%s\n", sqlite3_column_text(pSql, 0));
        }
      }
      shellReset(&rc, pSql);
    }
    shellFinalize(&rc, pSql);
  }

  sqlite3_free(zDir);
  sqlite3_free(zWhere);
  return rc;
}


/*
** Implementation of .ar "create" and "update" commands.
**
** Create the "sqlar" table in the database if it does not already exist.
** Then add each file in the azFile[] array to the archive. Directories
** are added recursively. If argument bVerbose is non-zero, a message is
** printed on stdout for each file archived.
**
** The create command is the same as update, except that it drops
** any existing "sqlar" table before beginning.
*/
static int arCreateUpdate(
  ShellState *p,                  /* Shell state pointer */
  sqlite3 *db,
  ArCommand *pAr,                 /* Command arguments and options */
  int bUpdate
){
  const char *zSql = "SELECT name, mode, mtime, data FROM fsdir(?, ?)";
  const char *zCreate = 
      "CREATE TABLE IF NOT EXISTS sqlar(\n"
      "  name TEXT PRIMARY KEY,  -- name of the file\n"
      "  mode INT,               -- access permissions\n"
      "  mtime INT,              -- last modification time\n"
      "  sz INT,                 -- original file size\n"
      "  data BLOB               -- compressed content\n"
      ")";
  const char *zDrop = "DROP TABLE IF EXISTS sqlar";
  const char *zInsert = "REPLACE INTO sqlar VALUES(?,?,?,?,sqlar_compress(?))";

  sqlite3_stmt *pStmt = 0;        /* Directory traverser */
  sqlite3_stmt *pInsert = 0;      /* Compilation of zInsert */
  int i;                          /* For iterating through azFile[] */
  int rc;                         /* Return code */

  assert( pAr->bZip==0 );

  rc = sqlite3_exec(db, "SAVEPOINT ar;", 0, 0, 0);
  if( rc!=SQLITE_OK ) return rc;

  if( bUpdate==0 ){
    rc = sqlite3_exec(db, zDrop, 0, 0, 0);
    if( rc!=SQLITE_OK ) return rc;
  }

  rc = sqlite3_exec(db, zCreate, 0, 0, 0);
  shellPrepare(db, &rc, zInsert, &pInsert);
  shellPrepare(db, &rc, zSql, &pStmt);
  sqlite3_bind_text(pStmt, 2, pAr->zDir, -1, SQLITE_STATIC);

  for(i=0; i<pAr->nArg && rc==SQLITE_OK; i++){
    sqlite3_bind_text(pStmt, 1, pAr->azArg[i], -1, SQLITE_STATIC);
    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
      int sz;
      const char *zName = (const char*)sqlite3_column_text(pStmt, 0);
      int mode = sqlite3_column_int(pStmt, 1);
      unsigned int mtime = sqlite3_column_int(pStmt, 2);

      if( pAr->bVerbose ){
        raw_printf(p->out, "%s\n", zName);
      }

      sqlite3_bind_text(pInsert, 1, zName, -1, SQLITE_STATIC);
      sqlite3_bind_int(pInsert, 2, mode);
      sqlite3_bind_int64(pInsert, 3, (sqlite3_int64)mtime);

      if( S_ISDIR(mode) ){
        sz = 0;
        sqlite3_bind_null(pInsert, 5);
      }else{
        sqlite3_bind_value(pInsert, 5, sqlite3_column_value(pStmt, 3));
        if( S_ISLNK(mode) ){
          sz = -1;
        }else{
          sz = sqlite3_column_bytes(pStmt, 3);
        }
      }

      sqlite3_bind_int(pInsert, 4, sz);
      sqlite3_step(pInsert);
      rc = sqlite3_reset(pInsert);
    }
    shellReset(&rc, pStmt);
  }

  if( rc!=SQLITE_OK ){
    sqlite3_exec(db, "ROLLBACK TO ar; RELEASE ar;", 0, 0, 0);
  }else{
    rc = sqlite3_exec(db, "RELEASE ar;", 0, 0, 0);
  }
  shellFinalize(&rc, pStmt);
  shellFinalize(&rc, pInsert);
  return rc;
}

/*
** Implementation of .ar "Create" command. 
**
** Create the "sqlar" table in the database if it does not already exist.
** Then add each file in the azFile[] array to the archive. Directories
** are added recursively. If argument bVerbose is non-zero, a message is
** printed on stdout for each file archived.
*/
static int arCreateCommand(
  ShellState *p,                  /* Shell state pointer */
  sqlite3 *db,
  ArCommand *pAr                  /* Command arguments and options */
){
  return arCreateUpdate(p, db, pAr, 0);
}

/*
** Implementation of .ar "Update" command. 
*/
static int arUpdateCmd(ShellState *p, sqlite3 *db, ArCommand *pAr){
  return arCreateUpdate(p, db, pAr, 1);
}


/*
** Implementation of ".ar" dot command.
*/
static int arDotCommand(
  ShellState *pState,             /* Current shell tool state */
  char **azArg,                   /* Array of arguments passed to dot command */
  int nArg                        /* Number of entries in azArg[] */
){
  ArCommand cmd;
  int rc;
  rc = arParseCommand(azArg, nArg, &cmd);
  if( rc==SQLITE_OK ){
    sqlite3 *db = 0;              /* Database handle to use as archive */

    if( cmd.bZip ){
      if( cmd.zFile==0 ){
        raw_printf(stderr, "zip format requires a --file switch\n");
        return SQLITE_ERROR;
      }else
      if( cmd.eCmd==AR_CMD_CREATE || cmd.eCmd==AR_CMD_UPDATE ){
        raw_printf(stderr, "zip archives are read-only\n");
        return SQLITE_ERROR;
      }
      db = pState->db;
    }else if( cmd.zFile ){
      int flags;
      if( cmd.eCmd==AR_CMD_CREATE || cmd.eCmd==AR_CMD_UPDATE ){
        flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE;
      }else{
        flags = SQLITE_OPEN_READONLY;
      }
      rc = sqlite3_open_v2(cmd.zFile, &db, flags, 0);
      if( rc!=SQLITE_OK ){
        raw_printf(stderr, "cannot open file: %s (%s)\n", 
            cmd.zFile, sqlite3_errmsg(db)
        );
        sqlite3_close(db);
        return rc;
      }
      sqlite3_fileio_init(db, 0, 0);
#ifdef SQLITE_HAVE_ZLIB
      sqlite3_sqlar_init(db, 0, 0);
#endif
    }else{
      db = pState->db;
    }

    switch( cmd.eCmd ){
      case AR_CMD_CREATE:
        rc = arCreateCommand(pState, db, &cmd);
        break;

      case AR_CMD_EXTRACT:
        rc = arExtractCommand(pState, db, &cmd);
        break;

      case AR_CMD_LIST:
        rc = arListCommand(pState, db, &cmd);
        break;

      case AR_CMD_HELP:
        arUsage(pState->out);
        break;

      default:
        assert( cmd.eCmd==AR_CMD_UPDATE );
        rc = arUpdateCmd(pState, db, &cmd);
        break;
    }

    if( cmd.zFile ){
      sqlite3_close(db);
    }
  }

  return rc;
}
/* End of the ".archive" or ".ar" command logic
**********************************************************************************/
#endif /* !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(SQLITE_HAVE_ZLIB) */

/*
** Implementation of ".expert" dot command.
*/
static int expertDotCommand(
  ShellState *pState,             /* Current shell tool state */
  char **azArg,                   /* Array of arguments passed to dot command */
  int nArg                        /* Number of entries in azArg[] */
){
  int rc = SQLITE_OK;
  char *zErr = 0;
  int i;
  int iSample = 0;

  assert( pState->expert.pExpert==0 );
  memset(&pState->expert, 0, sizeof(ExpertInfo));

  for(i=1; rc==SQLITE_OK && i<nArg; i++){
    char *z = azArg[i];
    int n;
    if( z[0]=='-' && z[1]=='-' ) z++;
    n = strlen30(z);
    if( n>=2 && 0==strncmp(z, "-verbose", n) ){
      pState->expert.bVerbose = 1;
    }
    else if( n>=2 && 0==strncmp(z, "-sample", n) ){
      if( i==(nArg-1) ){
        raw_printf(stderr, "option requires an argument: %s\n", z);
        rc = SQLITE_ERROR;
      }else{
        iSample = (int)integerValue(azArg[++i]);
        if( iSample<0 || iSample>100 ){
          raw_printf(stderr, "value out of range: %s\n", azArg[i]);
          rc = SQLITE_ERROR;
        }
      }
    }
    else{
      raw_printf(stderr, "unknown option: %s\n", z);
      rc = SQLITE_ERROR;
    }
  }

  if( rc==SQLITE_OK ){
    pState->expert.pExpert = sqlite3_expert_new(pState->db, &zErr);
    if( pState->expert.pExpert==0 ){
      raw_printf(stderr, "sqlite3_expert_new: %s\n", zErr);
      rc = SQLITE_ERROR;
    }else{
      sqlite3_expert_config(
          pState->expert.pExpert, EXPERT_CONFIG_SAMPLE, iSample
      );
    }
  }

  return rc;
}


/*
** If an input line begins with "." then invoke this routine to
** process that line.
**
** Return 1 on error, 2 to exit, and 0 otherwise.
*/
static int do_meta_command(char *zLine, ShellState *p){
  int h = 1;
  int nArg = 0;
  int n, c;
  int rc = 0;
  char *azArg[50];

  if( p->expert.pExpert ){
    expertFinish(p, 1, 0);
  }

  /* Parse the input line into tokens.
  */
  while( zLine[h] && nArg<ArraySize(azArg) ){
    while( IsSpace(zLine[h]) ){ h++; }
    if( zLine[h]==0 ) break;
    if( zLine[h]=='\'' || zLine[h]=='"' ){