fts0tokenize.h

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/** @file include/fts0tokenize.h
 Full Text Search plugin tokenizer refer to MyISAM
 
 Created 2014/11/17 Shaohua Wang
 ***********************************************************************/
 
#include <cstdint>
 
#include "ft_global.h"
#include "mysql/plugin_ftparser.h"
#include "mysql/strings/m_ctype.h"
 
/* Macros and structs below are from ftdefs.h in MyISAM */
/** Check a char is true word */
inline bool true_word_char(int c, uint8_t ch) {
  return ((c & (MY_CHAR_U | MY_CHAR_L | MY_CHAR_NMR)) != 0) || ch == '_';
}
 
/** Boolean search syntax */
static const char *fts_boolean_syntax = DEFAULT_FTB_SYNTAX;
 
#define FTB_YES (fts_boolean_syntax[0])
#define FTB_EGAL (fts_boolean_syntax[1])
#define FTB_NO (fts_boolean_syntax[2])
#define FTB_INC (fts_boolean_syntax[3])
#define FTB_DEC (fts_boolean_syntax[4])
#define FTB_LBR (fts_boolean_syntax[5])
#define FTB_RBR (fts_boolean_syntax[6])
#define FTB_NEG (fts_boolean_syntax[7])
#define FTB_TRUNC (fts_boolean_syntax[8])
#define FTB_LQUOT (fts_boolean_syntax[10])
#define FTB_RQUOT (fts_boolean_syntax[11])
 
/** FTS query token */
struct FT_WORD {
  uchar *pos;    /*!< word start pointer */
  uint len;      /*!< word len */
  double weight; /*!< word weight, unused in innodb */
};
 
/** Tokenizer for ngram referring to ft_get_word(ft_parser.c) in MyISAM.
Differences: a. code format changed; b. stopword processing removed.
@param[in]      cs      charset
@param[in,out]  start   doc start pointer
@param[in,out]  end     doc end pointer
@param[in,out]  word    token
@param[in,out]  info    token info
@retval 0       eof
@retval 1       word found
@retval 2       left bracket
@retval 3       right bracket
@retval 4       stopword found */
inline uchar fts_get_word(const CHARSET_INFO *cs, uchar **start, uchar *end,
                          FT_WORD *word, MYSQL_FTPARSER_BOOLEAN_INFO *info) {
  uchar *doc = *start;
  int ctype;
  int mbl;
 
  info->yesno = (FTB_YES == ' ') ? 1 : (info->quot != nullptr);
  info->weight_adjust = info->wasign = 0;
  info->type = FT_TOKEN_EOF;
 
  while (doc < end) {
    for (; doc < end; doc += (mbl > 0 ? mbl : (mbl < 0 ? -mbl : 1))) {
      mbl = cs->cset->ctype(cs, &ctype, doc, end);
 
      if (true_word_char(ctype, *doc)) {
        break;
      }
 
      if (*doc == FTB_RQUOT && info->quot) {
        *start = doc + 1;
        info->type = FT_TOKEN_RIGHT_PAREN;
 
        return (info->type);
      }
 
      if (!info->quot) {
        if (*doc == FTB_LBR || *doc == FTB_RBR || *doc == FTB_LQUOT) {
          /* param->prev=' '; */
          *start = doc + 1;
          if (*doc == FTB_LQUOT) {
            info->quot = (char *)1;
          }
 
          info->type =
              (*doc == FTB_RBR ? FT_TOKEN_RIGHT_PAREN : FT_TOKEN_LEFT_PAREN);
 
          return (info->type);
        }
 
        if (info->prev == ' ') {
          if (*doc == FTB_YES) {
            info->yesno = +1;
            continue;
          } else if (*doc == FTB_EGAL) {
            info->yesno = 0;
            continue;
          } else if (*doc == FTB_NO) {
            info->yesno = -1;
            continue;
          } else if (*doc == FTB_INC) {
            info->weight_adjust++;
            continue;
          } else if (*doc == FTB_DEC) {
            info->weight_adjust--;
            continue;
          } else if (*doc == FTB_NEG) {
            info->wasign = !info->wasign;
            continue;
          }
        }
      }
 
      info->prev = *doc;
      info->yesno = (FTB_YES == ' ') ? 1 : (info->quot != nullptr);
      info->weight_adjust = info->wasign = 0;
    }
 
    for (word->pos = doc; doc < end;
         doc += (mbl > 0 ? mbl : (mbl < 0 ? -mbl : 1))) {
      mbl = cs->cset->ctype(cs, &ctype, doc, end);
 
      if (!true_word_char(ctype, *doc)) {
        break;
      }
    }
 
    /* Be sure *prev is true_word_char. */
    info->prev = 'A';
    word->len = (uint)(doc - word->pos);
 
    if ((info->trunc = (doc < end && *doc == FTB_TRUNC))) {
      doc++;
    }
 
    /* We don't check stopword here. */
    *start = doc;
    info->type = FT_TOKEN_WORD;
 
    return (info->type);
  }
 
  if (info->quot) {
    *start = doc;
    info->type = FT_TOKEN_RIGHT_PAREN;
  }
 
  return (info->type);
}