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Overview
Comment:Small performance increase and size reduction in the implementation of the LIKE and GLOB operators.
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SHA3-256: f97626f921dafe596b615a168ef31987f4a1c0b52956443e1a5c1148b49cab74
User & Date: drh 2019-04-30 11:54:36.560
Context
2019-04-30
14:26
Fix an error message in the Lemon parser generator. (check-in: b6d7d42b74 user: drh tags: trunk)
11:54
Small performance increase and size reduction in the implementation of the LIKE and GLOB operators. (check-in: f97626f921 user: drh tags: trunk)
01:08
Slightly smaller and faster implementation of the OP_MakeRecord opcode. (check-in: 3bdce7ef1a user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/func.c.
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#ifdef SQLITE_TEST
    sqlite3_like_count++;
#endif
    sqlite3_result_int(context, 0);
    return;
  }
#endif
  zB = sqlite3_value_text(argv[0]);
  zA = sqlite3_value_text(argv[1]);

  /* Limit the length of the LIKE or GLOB pattern to avoid problems
  ** of deep recursion and N*N behavior in patternCompare().
  */
  nPat = sqlite3_value_bytes(argv[0]);
  testcase( nPat==db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH] );
  testcase( nPat==db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]+1 );
  if( nPat > db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH] ){
    sqlite3_result_error(context, "LIKE or GLOB pattern too complex", -1);
    return;
  }
  assert( zB==sqlite3_value_text(argv[0]) );  /* Encoding did not change */

  if( argc==3 ){
    /* The escape character string must consist of a single UTF-8 character.
    ** Otherwise, return an error.
    */
    const unsigned char *zEsc = sqlite3_value_text(argv[2]);
    if( zEsc==0 ) return;
    if( sqlite3Utf8CharLen((char*)zEsc, -1)!=1 ){
      sqlite3_result_error(context, 
          "ESCAPE expression must be a single character", -1);
      return;
    }
    escape = sqlite3Utf8Read(&zEsc);
  }else{
    escape = pInfo->matchSet;
  }


  if( zA && zB ){
#ifdef SQLITE_TEST
    sqlite3_like_count++;
#endif
    sqlite3_result_int(context,
                      patternCompare(zB, zA, pInfo, escape)==SQLITE_MATCH);
  }








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#ifdef SQLITE_TEST
    sqlite3_like_count++;
#endif
    sqlite3_result_int(context, 0);
    return;
  }
#endif



  /* Limit the length of the LIKE or GLOB pattern to avoid problems
  ** of deep recursion and N*N behavior in patternCompare().
  */
  nPat = sqlite3_value_bytes(argv[0]);
  testcase( nPat==db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH] );
  testcase( nPat==db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]+1 );
  if( nPat > db->aLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH] ){
    sqlite3_result_error(context, "LIKE or GLOB pattern too complex", -1);
    return;
  }


  if( argc==3 ){
    /* The escape character string must consist of a single UTF-8 character.
    ** Otherwise, return an error.
    */
    const unsigned char *zEsc = sqlite3_value_text(argv[2]);
    if( zEsc==0 ) return;
    if( sqlite3Utf8CharLen((char*)zEsc, -1)!=1 ){
      sqlite3_result_error(context, 
          "ESCAPE expression must be a single character", -1);
      return;
    }
    escape = sqlite3Utf8Read(&zEsc);
  }else{
    escape = pInfo->matchSet;
  }
  zB = sqlite3_value_text(argv[0]);
  zA = sqlite3_value_text(argv[1]);
  if( zA && zB ){
#ifdef SQLITE_TEST
    sqlite3_like_count++;
#endif
    sqlite3_result_int(context,
                      patternCompare(zB, zA, pInfo, escape)==SQLITE_MATCH);
  }
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