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/*
** Copyright (c) 2013 D. Richard Hipp
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of the Simplified BSD License (also
** known as the "2-Clause License" or "FreeBSD License".)
**
** This program is distributed in the hope that it will be useful,
** but without any warranty; without even the implied warranty of
** merchantability or fitness for a particular purpose.
**
** Author contact information:
**   drh@hwaci.com
**   http://www.hwaci.com/drh/
**
*******************************************************************************
**
** This file is copied from ext/fts3/fts3_unicode2.c of SQLite3 with
** minor changes.
*/
#include "config.h"
#include "unicode.h"

/*
** Return true if the argument corresponds to a unicode codepoint
** classified as either a letter or a number. Otherwise false.
**
** The results are undefined if the value passed to this function
** is less than zero.
*/
int unicode_isalnum(int c){
  /* Each unsigned integer in the following array corresponds to a contiguous
  ** range of unicode codepoints that are not either letters or numbers (i.e.
  ** codepoints for which this function should return 0).
  **
  ** The most significant 22 bits in each 32-bit value contain the first
  ** codepoint in the range. The least significant 10 bits are used to store
  ** the size of the range (always at least 1). In other words, the value
  ** ((C<<22) + N) represents a range of N codepoints starting with codepoint
  ** C. It is not possible to represent a range larger than 1023 codepoints
  ** using this format.
  */
  static const unsigned int aEntry[] = {
    0x00000030, 0x0000E807, 0x00016C06, 0x0001EC2F, 0x0002AC07,
    0x0002D001, 0x0002D803, 0x0002EC01, 0x0002FC01, 0x00035C01,
    0x0003DC01, 0x000B0804, 0x000B480E, 0x000B9407, 0x000BB401,
    0x000BBC81, 0x000DD401, 0x000DF801, 0x000E1002, 0x000E1C01,
    0x000FD801, 0x00120808, 0x00156806, 0x00162402, 0x00163403,
    0x00164437, 0x0017CC02, 0x0018001D, 0x00187802, 0x00192C15,
    0x0019A804, 0x0019C001, 0x001B5001, 0x001B580F, 0x001B9C07,
    0x001BF402, 0x001C000E, 0x001C3C01, 0x001C4401, 0x001CC01B,
    0x001E980B, 0x001FAC09, 0x001FD804, 0x00205804, 0x00206C09,
    0x00209403, 0x0020A405, 0x0020C00F, 0x00216403, 0x00217801,
    0x00239020, 0x0024E803, 0x0024F812, 0x00254407, 0x00258804,
    0x0025C001, 0x00260403, 0x0026F001, 0x0026F807, 0x00271C02,
    0x00272C03, 0x00275C01, 0x00278802, 0x0027C802, 0x0027E802,
    0x00280403, 0x0028F001, 0x0028F805, 0x00291C02, 0x00292C03,
    0x00294401, 0x0029C002, 0x0029D401, 0x002A0403, 0x002AF001,
    0x002AF808, 0x002B1C03, 0x002B2C03, 0x002B8802, 0x002BC002,
    0x002C0403, 0x002CF001, 0x002CF807, 0x002D1C02, 0x002D2C03,
    0x002D5802, 0x002D8802, 0x002DC001, 0x002E0801, 0x002EF805,
    0x002F1803, 0x002F2804, 0x002F5C01, 0x002FCC08, 0x00300004,
    0x0030F807, 0x00311803, 0x00312804, 0x00315402, 0x00318802,
    0x0031FC01, 0x00320403, 0x0032F001, 0x0032F807, 0x00331803,
    0x00332804, 0x00335402, 0x00338802, 0x00340403, 0x0034F807,
    0x00351803, 0x00352804, 0x00355C01, 0x00358802, 0x0035E401,
    0x00360802, 0x00372801, 0x00373C06, 0x00375801, 0x00376008,
    0x0037C803, 0x0038C401, 0x0038D007, 0x0038FC01, 0x00391C09,
    0x00396802, 0x003AC401, 0x003AD006, 0x003AEC02, 0x003B2006,
    0x003C041F, 0x003CD00C, 0x003DC417, 0x003E340B, 0x003E6424,
    0x003EF80F, 0x003F380D, 0x0040AC14, 0x00412806, 0x00415804,
    0x00417803, 0x00418803, 0x00419C07, 0x0041C404, 0x0042080C,
    0x00423C01, 0x00426806, 0x0043EC01, 0x004D740C, 0x004E400A,
    0x00500001, 0x0059B402, 0x005A0001, 0x005A6C02, 0x005BAC03,
    0x005C4803, 0x005CC805, 0x005D4802, 0x005DC802, 0x005ED023,
    0x005F6004, 0x005F7401, 0x0060000F, 0x0062A401, 0x0064800C,
    0x0064C00C, 0x00650001, 0x00651002, 0x0066C011, 0x00672002,
    0x00677822, 0x00685C05, 0x00687802, 0x0069540A, 0x0069801D,
    0x0069FC01, 0x006A8007, 0x006AA006, 0x006AC00F, 0x006C0005,
    0x006CD011, 0x006D6823, 0x006E0003, 0x006E840D, 0x006F980E,
    0x006FF004, 0x00709014, 0x0070EC05, 0x0071F802, 0x00730008,
    0x00734019, 0x0073B401, 0x0073C803, 0x0073E002, 0x00770036,
    0x0077F004, 0x007EF401, 0x007EFC03, 0x007F3403, 0x007F7403,
    0x007FB403, 0x007FF402, 0x00800065, 0x0081980A, 0x0081E805,
    0x00822805, 0x0082801E, 0x00834021, 0x00840002, 0x00840C04,
    0x00842002, 0x00845001, 0x00845803, 0x00847806, 0x00849401,
    0x00849C01, 0x0084A401, 0x0084B801, 0x0084E802, 0x00850005,
    0x00852804, 0x00853C01, 0x0086426B, 0x00900027, 0x0091000B,
    0x0092704E, 0x00940276, 0x009E53E0, 0x00ADD820, 0x00AE6022,
    0x00AEF40C, 0x00AF2808, 0x00B39406, 0x00B3BC03, 0x00B3E404,
    0x00B3F802, 0x00B5C001, 0x00B5FC01, 0x00B7804F, 0x00B8C013,
    0x00BA001A, 0x00BA6C59, 0x00BC00D6, 0x00BFC00C, 0x00C00005,
    0x00C02019, 0x00C0A807, 0x00C0D802, 0x00C0F403, 0x00C26404,
    0x00C28001, 0x00C3EC01, 0x00C64002, 0x00C6580A, 0x00C70024,
    0x00C8001F, 0x00C8A81E, 0x00C94001, 0x00C98020, 0x00CA2827,
    0x00CB003F, 0x00CC0100, 0x01370040, 0x02924037, 0x0293F802,
    0x02983403, 0x0299BC10, 0x029A7C01, 0x029BC008, 0x029C0017,
    0x029C8002, 0x029E2402, 0x02A00801, 0x02A01801, 0x02A02C01,
    0x02A08C09, 0x02A0D804, 0x02A1D004, 0x02A20002, 0x02A2D011,
    0x02A33802, 0x02A38012, 0x02A3E003, 0x02A4980A, 0x02A51C0D,
    0x02A57C01, 0x02A60004, 0x02A6CC1B, 0x02A77802, 0x02A79401,
    0x02A8A40E, 0x02A90C01, 0x02A93002, 0x02A97004, 0x02A9DC03,
    0x02A9EC03, 0x02AAC001, 0x02AAC803, 0x02AADC02, 0x02AAF802,
    0x02AB0401, 0x02AB7802, 0x02ABAC07, 0x02ABD402, 0x02AD6C01,
    0x02AF8C0B, 0x03600001, 0x036DFC02, 0x036FFC02, 0x037FFC01,
    0x03EC7801, 0x03ECA401, 0x03EEC810, 0x03F4F802, 0x03F7F002,
    0x03F8001A, 0x03F8800E, 0x03F8C023, 0x03F95013, 0x03F9A004,
    0x03FBFC01, 0x03FC040F, 0x03FC6807, 0x03FCEC06, 0x03FD6C0B,
    0x03FF8007, 0x03FFA007, 0x03FFE405, 0x04040003, 0x0404DC09,
    0x0405E411, 0x04063001, 0x0406400C, 0x04068001, 0x0407402E,
    0x040B8001, 0x040DD805, 0x040E7C01, 0x040F4001, 0x0415BC01,
    0x04215C01, 0x0421DC02, 0x04247C01, 0x0424FC01, 0x04280403,
    0x04281402, 0x04283004, 0x0428E003, 0x0428FC01, 0x04294009,
    0x0429FC01, 0x042B2001, 0x042B9402, 0x042BC007, 0x042CE407,
    0x042E6404, 0x04400003, 0x0440E016, 0x0441FC04, 0x0442C012,
    0x04440003, 0x04449C0E, 0x04450004, 0x0445CC03, 0x04460003,
    0x0446CC0E, 0x04471404, 0x04473401, 0x0448B012, 0x044B7C0C,
    0x044C0403, 0x044CF001, 0x044CF807, 0x044D1C02, 0x044D2C03,
    0x044D5C01, 0x044D8802, 0x044D9807, 0x044DC005, 0x0452C014,
    0x04531801, 0x0456BC07, 0x0456E012, 0x0458C014, 0x045AAC0D,
    0x0491C005, 0x05A9B802, 0x05ABC006, 0x05ACC010, 0x05AD1002,
    0x05BD442E, 0x05BE3C04, 0x06F27008, 0x074000F6, 0x07440027,
    0x0744A4B5, 0x07480046, 0x074C0057, 0x075B0401, 0x075B6C01,
    0x075BEC01, 0x075C5401, 0x075CD401, 0x075D3C01, 0x075DBC01,
    0x075E2401, 0x075EA401, 0x075F0C01, 0x07A34007, 0x07BBC002,
    0x07C0002C, 0x07C0C064, 0x07C2800F, 0x07C2C40F, 0x07C3040F,
    0x07C34425, 0x07C4401F, 0x07C4C03C, 0x07C5C02B, 0x07C7981D,
    0x07C8402B, 0x07C90009, 0x07C94002, 0x07CC002D, 0x07CCC04E,
    0x07CE004F, 0x07CF5024, 0x07D000FF, 0x07D4004B, 0x07D5402A,
    0x07D5EC29, 0x07D6949E, 0x07D9148B, 0x07DB800D, 0x07DBC004,
    0x07DC0074, 0x07DE0055, 0x07E0000C, 0x07E04038, 0x07E1400A,
    0x07E18028, 0x07E2401E, 0x38000401, 0x38008060, 0x380400F0,
  };
  static const unsigned int aAscii[4] = {
    0xFFFFFFFF, 0xFC00FFFF, 0xF8000001, 0xF8000001,
  };

  if( c<128 ){
    return ( (aAscii[c >> 5] & (1 << (c & 0x001F)))==0 );
  }else if( c<(1<<22) ){
    unsigned int key = (((unsigned int)c)<<10) | 0x000003FF;
    int iRes = 0;
    int iHi = sizeof(aEntry)/sizeof(aEntry[0]) - 1;
    int iLo = 0;
    while( iHi>=iLo ){
      int iTest = (iHi + iLo) / 2;
      if( key >= aEntry[iTest] ){
        iRes = iTest;
        iLo = iTest+1;
      }else{
        iHi = iTest-1;
      }
    }
    assert( aEntry[0]<key );
    assert( key>=aEntry[iRes] );
    return (((unsigned int)c) >= ((aEntry[iRes]>>10) + (aEntry[iRes]&0x3FF)));
  }
  return 1;
}


/*
** If the argument is a codepoint corresponding to a lowercase letter
** in the ASCII range with a diacritic added, return the codepoint
** of the ASCII letter only. For example, if passed 235 - "LATIN
** SMALL LETTER E WITH DIAERESIS" - return 65 ("LATIN SMALL LETTER
** E"). The resuls of passing a codepoint that corresponds to an
** uppercase letter are undefined.
*/
static int unicode_remove_diacritic(int c){
  static const unsigned short aDia[] = {
        0,  1797,  1848,  1859,  1891,  1928,  1940,  1995,
     2024,  2040,  2060,  2110,  2168,  2206,  2264,  2286,
     2344,  2383,  2472,  2488,  2516,  2596,  2668,  2732,
     2782,  2842,  2894,  2954,  2984,  3000,  3028,  3336,
     3456,  3696,  3712,  3728,  3744,  3896,  3912,  3928,
     3968,  4008,  4040,  4106,  4138,  4170,  4202,  4234,
     4266,  4296,  4312,  4344,  4408,  4424,  4472,  4504,
     6148,  6198,  6264,  6280,  6360,  6429,  6505,  6529,
    61448, 61468, 61534, 61592, 61642, 61688, 61704, 61726,
    61784, 61800, 61836, 61880, 61914, 61948, 61998, 62122,
    62154, 62200, 62218, 62302, 62364, 62442, 62478, 62536,
    62554, 62584, 62604, 62640, 62648, 62656, 62664, 62730,
    62924, 63050, 63082, 63274, 63390,
  };
  static const char aChar[] = {
    '\0', 'a',  'c',  'e',  'i',  'n',  'o',  'u',  'y',  'y',  'a',  'c',
    'd',  'e',  'e',  'g',  'h',  'i',  'j',  'k',  'l',  'n',  'o',  'r',
    's',  't',  'u',  'u',  'w',  'y',  'z',  'o',  'u',  'a',  'i',  'o',
    'u',  'g',  'k',  'o',  'j',  'g',  'n',  'a',  'e',  'i',  'o',  'r',
    'u',  's',  't',  'h',  'a',  'e',  'o',  'y',  '\0', '\0', '\0', '\0',
    '\0', '\0', '\0', '\0', 'a',  'b',  'd',  'd',  'e',  'f',  'g',  'h',
    'h',  'i',  'k',  'l',  'l',  'm',  'n',  'p',  'r',  'r',  's',  't',
    'u',  'v',  'w',  'w',  'x',  'y',  'z',  'h',  't',  'w',  'y',  'a',
    'e',  'i',  'o',  'u',  'y',
  };

  unsigned int key = (((unsigned int)c)<<3) | 0x00000007;
  int iRes = 0;
  int iHi = sizeof(aDia)/sizeof(aDia[0]) - 1;
  int iLo = 0;
  while( iHi>=iLo ){
    int iTest = (iHi + iLo) / 2;
    if( key >= aDia[iTest] ){
      iRes = iTest;
      iLo = iTest+1;
    }else{
      iHi = iTest-1;
    }
  }
  assert( key>=aDia[iRes] );
  return ((c > (aDia[iRes]>>3) + (aDia[iRes]&0x07)) ? c : (int)aChar[iRes]);
}


/*
** Return true if the argument interpreted as a unicode codepoint
** is a diacritical modifier character.
*/
int unicode_is_diacritic(int c){
  unsigned int mask0 = 0x08029FDF;
  unsigned int mask1 = 0x000361F8;
  if( c<768 || c>817 ) return 0;
  return (c < 768+32) ?
      (mask0 & (1 << (c-768))) :
      (mask1 & (1 << (c-768-32)));
}


/*
** Interpret the argument as a unicode codepoint. If the codepoint
** is an upper case character that has a lower case equivalent,
** return the codepoint corresponding to the lower case version.
** Otherwise, return a copy of the argument.
**
** The results are undefined if the value passed to this function
** is less than zero.
*/
int unicode_fold(int c, int bRemoveDiacritic){
  /* Each entry in the following array defines a rule for folding a range
  ** of codepoints to lower case. The rule applies to a range of nRange
  ** codepoints starting at codepoint iCode.
  **
  ** If the least significant bit in flags is clear, then the rule applies
  ** to all nRange codepoints (i.e. all nRange codepoints are upper case and
  ** need to be folded). Or, if it is set, then the rule only applies to
  ** every second codepoint in the range, starting with codepoint C.
  **
  ** The 7 most significant bits in flags are an index into the aiOff[]
  ** array. If a specific codepoint C does require folding, then its lower
  ** case equivalent is ((C + aiOff[flags>>1]) & 0xFFFF).
  **
  ** The contents of this array are generated by parsing the CaseFolding.txt
  ** file distributed as part of the "Unicode Character Database". See
  ** http://www.unicode.org for details.
  */
  static const struct TableEntry {
    unsigned short iCode;
    unsigned char flags;
    unsigned char nRange;
  } aEntry[] = {
    {65, 14, 26},          {181, 64, 1},          {192, 14, 23},
    {216, 14, 7},          {256, 1, 48},          {306, 1, 6},
    {313, 1, 16},          {330, 1, 46},          {376, 126, 1},
    {377, 1, 6},           {383, 114, 1},         {385, 50, 1},
    {386, 1, 4},           {390, 44, 1},          {391, 0, 1},
    {393, 42, 2},          {395, 0, 1},           {398, 32, 1},
    {399, 38, 1},          {400, 40, 1},          {401, 0, 1},
    {403, 42, 1},          {404, 46, 1},          {406, 52, 1},
    {407, 48, 1},          {408, 0, 1},           {412, 52, 1},
    {413, 54, 1},          {415, 56, 1},          {416, 1, 6},
    {422, 60, 1},          {423, 0, 1},           {425, 60, 1},
    {428, 0, 1},           {430, 60, 1},          {431, 0, 1},
    {433, 58, 2},          {435, 1, 4},           {439, 62, 1},
    {440, 0, 1},           {444, 0, 1},           {452, 2, 1},
    {453, 0, 1},           {455, 2, 1},           {456, 0, 1},
    {458, 2, 1},           {459, 1, 18},          {478, 1, 18},
    {497, 2, 1},           {498, 1, 4},           {502, 132, 1},
    {503, 144, 1},         {504, 1, 40},          {544, 120, 1},
    {546, 1, 18},          {570, 70, 1},          {571, 0, 1},
    {573, 118, 1},         {574, 68, 1},          {577, 0, 1},
    {579, 116, 1},         {580, 28, 1},          {581, 30, 1},
    {582, 1, 10},          {837, 36, 1},          {880, 1, 4},
    {886, 0, 1},           {895, 36, 1},          {902, 18, 1},
    {904, 16, 3},          {908, 26, 1},          {910, 24, 2},
    {913, 14, 17},         {931, 14, 9},          {962, 0, 1},
    {975, 4, 1},           {976, 150, 1},         {977, 152, 1},
    {981, 156, 1},         {982, 154, 1},         {984, 1, 24},
    {1008, 146, 1},        {1009, 148, 1},        {1012, 140, 1},
    {1013, 138, 1},        {1015, 0, 1},          {1017, 162, 1},
    {1018, 0, 1},          {1021, 120, 3},        {1024, 34, 16},
    {1040, 14, 32},        {1120, 1, 34},         {1162, 1, 54},
    {1216, 6, 1},          {1217, 1, 14},         {1232, 1, 96},
    {1329, 22, 38},        {4256, 66, 38},        {4295, 66, 1},
    {4301, 66, 1},         {7680, 1, 150},        {7835, 142, 1},
    {7838, 106, 1},        {7840, 1, 96},         {7944, 160, 8},
    {7960, 160, 6},        {7976, 160, 8},        {7992, 160, 8},
    {8008, 160, 6},        {8025, 161, 8},        {8040, 160, 8},
    {8072, 160, 8},        {8088, 160, 8},        {8104, 160, 8},
    {8120, 160, 2},        {8122, 136, 2},        {8124, 158, 1},
    {8126, 110, 1},        {8136, 134, 4},        {8140, 158, 1},
    {8152, 160, 2},        {8154, 130, 2},        {8168, 160, 2},
    {8170, 128, 2},        {8172, 162, 1},        {8184, 122, 2},
    {8186, 124, 2},        {8188, 158, 1},        {8486, 108, 1},
    {8490, 102, 1},        {8491, 104, 1},        {8498, 12, 1},
    {8544, 8, 16},         {8579, 0, 1},          {9398, 10, 26},
    {11264, 22, 47},       {11360, 0, 1},         {11362, 98, 1},
    {11363, 112, 1},       {11364, 100, 1},       {11367, 1, 6},
    {11373, 94, 1},        {11374, 96, 1},        {11375, 90, 1},
    {11376, 92, 1},        {11378, 0, 1},         {11381, 0, 1},
    {11390, 88, 2},        {11392, 1, 100},       {11499, 1, 4},
    {11506, 0, 1},         {42560, 1, 46},        {42624, 1, 28},
    {42786, 1, 14},        {42802, 1, 62},        {42873, 1, 4},
    {42877, 86, 1},        {42878, 1, 10},        {42891, 0, 1},
    {42893, 82, 1},        {42896, 1, 4},         {42902, 1, 20},
    {42922, 76, 1},        {42923, 72, 1},        {42924, 74, 1},
    {42925, 78, 1},        {42928, 84, 1},        {42929, 80, 1},
    {65313, 14, 26},
  };
  static const unsigned short aiOff[] = {
   1,     2,     8,     15,    16,    26,    28,    32,
   37,    38,    40,    48,    63,    64,    69,    71,
   79,    80,    116,   202,   203,   205,   206,   207,
   209,   210,   211,   213,   214,   217,   218,   219,
   775,   7264,  10792, 10795, 23217, 23221, 23228, 23231,
   23254, 23256, 23278, 30204, 54721, 54753, 54754, 54756,
   54787, 54793, 54809, 57153, 57274, 57921, 58019, 58363,
   61722, 65268, 65341, 65373, 65406, 65408, 65410, 65415,
   65424, 65436, 65439, 65450, 65462, 65472, 65476, 65478,
   65480, 65482, 65488, 65506, 65511, 65514, 65521, 65527,
   65528, 65529,
  };

  int ret = c;

  assert( c>=0 );
  assert( sizeof(unsigned short)==2 && sizeof(unsigned char)==1 );

  if( c<128 ){
    if( c>='A' && c<='Z' ) ret = c + ('a' - 'A');
  }else if( c<65536 ){
    int iHi = sizeof(aEntry)/sizeof(aEntry[0]) - 1;
    int iLo = 0;
    int iRes = -1;

    while( iHi>=iLo ){
      int iTest = (iHi + iLo) / 2;
      int cmp = (c - aEntry[iTest].iCode);
      if( cmp>=0 ){
        iRes = iTest;
        iLo = iTest+1;
      }else{
        iHi = iTest-1;
      }
    }
    assert( iRes<0 || c>=aEntry[iRes].iCode );

    if( iRes>=0 ){
      const struct TableEntry *p = &aEntry[iRes];
      if( c<(p->iCode + p->nRange) && 0==(0x01 & p->flags & (p->iCode ^ c)) ){
        ret = (c + (aiOff[p->flags>>1])) & 0x0000FFFF;
        assert( ret>0 );
      }
    }

    if( bRemoveDiacritic ) ret = unicode_remove_diacritic(ret);
  }

  else if( c>=66560 && c<66600 ){
    ret = c + 40;
  }
  else if( c>=71840 && c<71872 ){
    ret = c + 32;
  }

  return ret;
}