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| 1 /* | |
| 2 ** 2006 Oct 10 | |
| 3 ** | |
| 4 ** The author disclaims copyright to this source code. In place of | |
| 5 ** a legal notice, here is a blessing: | |
| 6 ** | |
| 7 ** May you do good and not evil. | |
| 8 ** May you find forgiveness for yourself and forgive others. | |
| 9 ** May you share freely, never taking more than you give. | |
| 10 ** | |
| 11 ****************************************************************************** | |
| 12 ** | |
| 13 ** Implementation of the "simple" full-text-search tokenizer. | |
| 14 */ | |
| 15 | |
| 16 /* | |
| 17 ** The code in this file is only compiled if: | |
| 18 ** | |
| 19 ** * The FTS2 module is being built as an extension | |
| 20 ** (in which case SQLITE_CORE is not defined), or | |
| 21 ** | |
| 22 ** * The FTS2 module is being built into the core of | |
| 23 ** SQLite (in which case SQLITE_ENABLE_FTS2 is defined). | |
| 24 */ | |
| 25 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS2) | |
| 26 | |
| 27 | |
| 28 #include <assert.h> | |
| 29 #include <stdlib.h> | |
| 30 #include <stdio.h> | |
| 31 #include <string.h> | |
| 32 #include <ctype.h> | |
| 33 | |
| 34 #include "fts2_tokenizer.h" | |
| 35 | |
| 36 typedef struct simple_tokenizer { | |
| 37 sqlite3_tokenizer base; | |
| 38 char delim[128]; /* flag ASCII delimiters */ | |
| 39 } simple_tokenizer; | |
| 40 | |
| 41 typedef struct simple_tokenizer_cursor { | |
| 42 sqlite3_tokenizer_cursor base; | |
| 43 const char *pInput; /* input we are tokenizing */ | |
| 44 int nBytes; /* size of the input */ | |
| 45 int iOffset; /* current position in pInput */ | |
| 46 int iToken; /* index of next token to be returned */ | |
| 47 char *pToken; /* storage for current token */ | |
| 48 int nTokenAllocated; /* space allocated to zToken buffer */ | |
| 49 } simple_tokenizer_cursor; | |
| 50 | |
| 51 | |
| 52 /* Forward declaration */ | |
| 53 static const sqlite3_tokenizer_module simpleTokenizerModule; | |
| 54 | |
| 55 static int simpleDelim(simple_tokenizer *t, unsigned char c){ | |
| 56 return c<0x80 && t->delim[c]; | |
| 57 } | |
| 58 | |
| 59 /* | |
| 60 ** Create a new tokenizer instance. | |
| 61 */ | |
| 62 static int simpleCreate( | |
| 63 int argc, const char * const *argv, | |
| 64 sqlite3_tokenizer **ppTokenizer | |
| 65 ){ | |
| 66 simple_tokenizer *t; | |
| 67 | |
| 68 t = (simple_tokenizer *) sqlite3_malloc(sizeof(*t)); | |
| 69 if( t==NULL ) return SQLITE_NOMEM; | |
| 70 memset(t, 0, sizeof(*t)); | |
| 71 | |
| 72 /* TODO(shess) Delimiters need to remain the same from run to run, | |
| 73 ** else we need to reindex. One solution would be a meta-table to | |
| 74 ** track such information in the database, then we'd only want this | |
| 75 ** information on the initial create. | |
| 76 */ | |
| 77 if( argc>1 ){ | |
| 78 int i, n = strlen(argv[1]); | |
| 79 for(i=0; i<n; i++){ | |
| 80 unsigned char ch = argv[1][i]; | |
| 81 /* We explicitly don't support UTF-8 delimiters for now. */ | |
| 82 if( ch>=0x80 ){ | |
| 83 sqlite3_free(t); | |
| 84 return SQLITE_ERROR; | |
| 85 } | |
| 86 t->delim[ch] = 1; | |
| 87 } | |
| 88 } else { | |
| 89 /* Mark non-alphanumeric ASCII characters as delimiters */ | |
| 90 int i; | |
| 91 for(i=1; i<0x80; i++){ | |
| 92 t->delim[i] = !isalnum(i); | |
| 93 } | |
| 94 } | |
| 95 | |
| 96 *ppTokenizer = &t->base; | |
| 97 return SQLITE_OK; | |
| 98 } | |
| 99 | |
| 100 /* | |
| 101 ** Destroy a tokenizer | |
| 102 */ | |
| 103 static int simpleDestroy(sqlite3_tokenizer *pTokenizer){ | |
| 104 sqlite3_free(pTokenizer); | |
| 105 return SQLITE_OK; | |
| 106 } | |
| 107 | |
| 108 /* | |
| 109 ** Prepare to begin tokenizing a particular string. The input | |
| 110 ** string to be tokenized is pInput[0..nBytes-1]. A cursor | |
| 111 ** used to incrementally tokenize this string is returned in | |
| 112 ** *ppCursor. | |
| 113 */ | |
| 114 static int simpleOpen( | |
| 115 sqlite3_tokenizer *pTokenizer, /* The tokenizer */ | |
| 116 const char *pInput, int nBytes, /* String to be tokenized */ | |
| 117 sqlite3_tokenizer_cursor **ppCursor /* OUT: Tokenization cursor */ | |
| 118 ){ | |
| 119 simple_tokenizer_cursor *c; | |
| 120 | |
| 121 c = (simple_tokenizer_cursor *) sqlite3_malloc(sizeof(*c)); | |
| 122 if( c==NULL ) return SQLITE_NOMEM; | |
| 123 | |
| 124 c->pInput = pInput; | |
| 125 if( pInput==0 ){ | |
| 126 c->nBytes = 0; | |
| 127 }else if( nBytes<0 ){ | |
| 128 c->nBytes = (int)strlen(pInput); | |
| 129 }else{ | |
| 130 c->nBytes = nBytes; | |
| 131 } | |
| 132 c->iOffset = 0; /* start tokenizing at the beginning */ | |
| 133 c->iToken = 0; | |
| 134 c->pToken = NULL; /* no space allocated, yet. */ | |
| 135 c->nTokenAllocated = 0; | |
| 136 | |
| 137 *ppCursor = &c->base; | |
| 138 return SQLITE_OK; | |
| 139 } | |
| 140 | |
| 141 /* | |
| 142 ** Close a tokenization cursor previously opened by a call to | |
| 143 ** simpleOpen() above. | |
| 144 */ | |
| 145 static int simpleClose(sqlite3_tokenizer_cursor *pCursor){ | |
| 146 simple_tokenizer_cursor *c = (simple_tokenizer_cursor *) pCursor; | |
| 147 sqlite3_free(c->pToken); | |
| 148 sqlite3_free(c); | |
| 149 return SQLITE_OK; | |
| 150 } | |
| 151 | |
| 152 /* | |
| 153 ** Extract the next token from a tokenization cursor. The cursor must | |
| 154 ** have been opened by a prior call to simpleOpen(). | |
| 155 */ | |
| 156 static int simpleNext( | |
| 157 sqlite3_tokenizer_cursor *pCursor, /* Cursor returned by simpleOpen */ | |
| 158 const char **ppToken, /* OUT: *ppToken is the token text */ | |
| 159 int *pnBytes, /* OUT: Number of bytes in token */ | |
| 160 int *piStartOffset, /* OUT: Starting offset of token */ | |
| 161 int *piEndOffset, /* OUT: Ending offset of token */ | |
| 162 int *piPosition /* OUT: Position integer of token */ | |
| 163 ){ | |
| 164 simple_tokenizer_cursor *c = (simple_tokenizer_cursor *) pCursor; | |
| 165 simple_tokenizer *t = (simple_tokenizer *) pCursor->pTokenizer; | |
| 166 unsigned char *p = (unsigned char *)c->pInput; | |
| 167 | |
| 168 while( c->iOffset<c->nBytes ){ | |
| 169 int iStartOffset; | |
| 170 | |
| 171 /* Scan past delimiter characters */ | |
| 172 while( c->iOffset<c->nBytes && simpleDelim(t, p[c->iOffset]) ){ | |
| 173 c->iOffset++; | |
| 174 } | |
| 175 | |
| 176 /* Count non-delimiter characters. */ | |
| 177 iStartOffset = c->iOffset; | |
| 178 while( c->iOffset<c->nBytes && !simpleDelim(t, p[c->iOffset]) ){ | |
| 179 c->iOffset++; | |
| 180 } | |
| 181 | |
| 182 if( c->iOffset>iStartOffset ){ | |
| 183 int i, n = c->iOffset-iStartOffset; | |
| 184 if( n>c->nTokenAllocated ){ | |
| 185 c->nTokenAllocated = n+20; | |
| 186 c->pToken = sqlite3_realloc(c->pToken, c->nTokenAllocated); | |
| 187 if( c->pToken==NULL ) return SQLITE_NOMEM; | |
| 188 } | |
| 189 for(i=0; i<n; i++){ | |
| 190 /* TODO(shess) This needs expansion to handle UTF-8 | |
| 191 ** case-insensitivity. | |
| 192 */ | |
| 193 unsigned char ch = p[iStartOffset+i]; | |
| 194 c->pToken[i] = (ch>='A' && ch<='Z') ? (ch-'A'+'a') : ch; | |
| 195 } | |
| 196 *ppToken = c->pToken; | |
| 197 *pnBytes = n; | |
| 198 *piStartOffset = iStartOffset; | |
| 199 *piEndOffset = c->iOffset; | |
| 200 *piPosition = c->iToken++; | |
| 201 | |
| 202 return SQLITE_OK; | |
| 203 } | |
| 204 } | |
| 205 return SQLITE_DONE; | |
| 206 } | |
| 207 | |
| 208 /* | |
| 209 ** The set of routines that implement the simple tokenizer | |
| 210 */ | |
| 211 static const sqlite3_tokenizer_module simpleTokenizerModule = { | |
| 212 0, | |
| 213 simpleCreate, | |
| 214 simpleDestroy, | |
| 215 simpleOpen, | |
| 216 simpleClose, | |
| 217 simpleNext, | |
| 218 }; | |
| 219 | |
| 220 /* | |
| 221 ** Allocate a new simple tokenizer. Return a pointer to the new | |
| 222 ** tokenizer in *ppModule | |
| 223 */ | |
| 224 void sqlite3Fts2SimpleTokenizerModule( | |
| 225 sqlite3_tokenizer_module const**ppModule | |
| 226 ){ | |
| 227 *ppModule = &simpleTokenizerModule; | |
| 228 } | |
| 229 | |
| 230 #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS2) */ | |
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Chromium Code Reviews
Issue 3108030:
Move bundled copy of sqlite one level deeper to better separate it... (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src/