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-rwxr-xr-xlibraries/sqlite/win32/fts1_tokenizer1.c221
1 files changed, 221 insertions, 0 deletions
diff --git a/libraries/sqlite/win32/fts1_tokenizer1.c b/libraries/sqlite/win32/fts1_tokenizer1.c
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1/*
2** The author disclaims copyright to this source code.
3**
4*************************************************************************
5** Implementation of the "simple" full-text-search tokenizer.
6*/
7
8/*
9** The code in this file is only compiled if:
10**
11** * The FTS1 module is being built as an extension
12** (in which case SQLITE_CORE is not defined), or
13**
14** * The FTS1 module is being built into the core of
15** SQLite (in which case SQLITE_ENABLE_FTS1 is defined).
16*/
17#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS1)
18
19
20#include <assert.h>
21#include <stdlib.h>
22#include <stdio.h>
23#include <string.h>
24#include <ctype.h>
25
26#include "fts1_tokenizer.h"
27
28typedef struct simple_tokenizer {
29 sqlite3_tokenizer base;
30 char delim[128]; /* flag ASCII delimiters */
31} simple_tokenizer;
32
33typedef struct simple_tokenizer_cursor {
34 sqlite3_tokenizer_cursor base;
35 const char *pInput; /* input we are tokenizing */
36 int nBytes; /* size of the input */
37 int iOffset; /* current position in pInput */
38 int iToken; /* index of next token to be returned */
39 char *pToken; /* storage for current token */
40 int nTokenAllocated; /* space allocated to zToken buffer */
41} simple_tokenizer_cursor;
42
43
44/* Forward declaration */
45static const sqlite3_tokenizer_module simpleTokenizerModule;
46
47static int isDelim(simple_tokenizer *t, unsigned char c){
48 return c<0x80 && t->delim[c];
49}
50
51/*
52** Create a new tokenizer instance.
53*/
54static int simpleCreate(
55 int argc, const char * const *argv,
56 sqlite3_tokenizer **ppTokenizer
57){
58 simple_tokenizer *t;
59
60 t = (simple_tokenizer *) calloc(sizeof(*t), 1);
61 if( t==NULL ) return SQLITE_NOMEM;
62
63 /* TODO(shess) Delimiters need to remain the same from run to run,
64 ** else we need to reindex. One solution would be a meta-table to
65 ** track such information in the database, then we'd only want this
66 ** information on the initial create.
67 */
68 if( argc>1 ){
69 int i, n = strlen(argv[1]);
70 for(i=0; i<n; i++){
71 unsigned char ch = argv[1][i];
72 /* We explicitly don't support UTF-8 delimiters for now. */
73 if( ch>=0x80 ){
74 free(t);
75 return SQLITE_ERROR;
76 }
77 t->delim[ch] = 1;
78 }
79 } else {
80 /* Mark non-alphanumeric ASCII characters as delimiters */
81 int i;
82 for(i=1; i<0x80; i++){
83 t->delim[i] = !isalnum(i);
84 }
85 }
86
87 *ppTokenizer = &t->base;
88 return SQLITE_OK;
89}
90
91/*
92** Destroy a tokenizer
93*/
94static int simpleDestroy(sqlite3_tokenizer *pTokenizer){
95 free(pTokenizer);
96 return SQLITE_OK;
97}
98
99/*
100** Prepare to begin tokenizing a particular string. The input
101** string to be tokenized is pInput[0..nBytes-1]. A cursor
102** used to incrementally tokenize this string is returned in
103** *ppCursor.
104*/
105static int simpleOpen(
106 sqlite3_tokenizer *pTokenizer, /* The tokenizer */
107 const char *pInput, int nBytes, /* String to be tokenized */
108 sqlite3_tokenizer_cursor **ppCursor /* OUT: Tokenization cursor */
109){
110 simple_tokenizer_cursor *c;
111
112 c = (simple_tokenizer_cursor *) malloc(sizeof(*c));
113 if( c==NULL ) return SQLITE_NOMEM;
114
115 c->pInput = pInput;
116 if( pInput==0 ){
117 c->nBytes = 0;
118 }else if( nBytes<0 ){
119 c->nBytes = (int)strlen(pInput);
120 }else{
121 c->nBytes = nBytes;
122 }
123 c->iOffset = 0; /* start tokenizing at the beginning */
124 c->iToken = 0;
125 c->pToken = NULL; /* no space allocated, yet. */
126 c->nTokenAllocated = 0;
127
128 *ppCursor = &c->base;
129 return SQLITE_OK;
130}
131
132/*
133** Close a tokenization cursor previously opened by a call to
134** simpleOpen() above.
135*/
136static int simpleClose(sqlite3_tokenizer_cursor *pCursor){
137 simple_tokenizer_cursor *c = (simple_tokenizer_cursor *) pCursor;
138 free(c->pToken);
139 free(c);
140 return SQLITE_OK;
141}
142
143/*
144** Extract the next token from a tokenization cursor. The cursor must
145** have been opened by a prior call to simpleOpen().
146*/
147static int simpleNext(
148 sqlite3_tokenizer_cursor *pCursor, /* Cursor returned by simpleOpen */
149 const char **ppToken, /* OUT: *ppToken is the token text */
150 int *pnBytes, /* OUT: Number of bytes in token */
151 int *piStartOffset, /* OUT: Starting offset of token */
152 int *piEndOffset, /* OUT: Ending offset of token */
153 int *piPosition /* OUT: Position integer of token */
154){
155 simple_tokenizer_cursor *c = (simple_tokenizer_cursor *) pCursor;
156 simple_tokenizer *t = (simple_tokenizer *) pCursor->pTokenizer;
157 unsigned char *p = (unsigned char *)c->pInput;
158
159 while( c->iOffset<c->nBytes ){
160 int iStartOffset;
161
162 /* Scan past delimiter characters */
163 while( c->iOffset<c->nBytes && isDelim(t, p[c->iOffset]) ){
164 c->iOffset++;
165 }
166
167 /* Count non-delimiter characters. */
168 iStartOffset = c->iOffset;
169 while( c->iOffset<c->nBytes && !isDelim(t, p[c->iOffset]) ){
170 c->iOffset++;
171 }
172
173 if( c->iOffset>iStartOffset ){
174 int i, n = c->iOffset-iStartOffset;
175 if( n>c->nTokenAllocated ){
176 c->nTokenAllocated = n+20;
177 c->pToken = realloc(c->pToken, c->nTokenAllocated);
178 if( c->pToken==NULL ) return SQLITE_NOMEM;
179 }
180 for(i=0; i<n; i++){
181 /* TODO(shess) This needs expansion to handle UTF-8
182 ** case-insensitivity.
183 */
184 unsigned char ch = p[iStartOffset+i];
185 c->pToken[i] = ch<0x80 ? tolower(ch) : ch;
186 }
187 *ppToken = c->pToken;
188 *pnBytes = n;
189 *piStartOffset = iStartOffset;
190 *piEndOffset = c->iOffset;
191 *piPosition = c->iToken++;
192
193 return SQLITE_OK;
194 }
195 }
196 return SQLITE_DONE;
197}
198
199/*
200** The set of routines that implement the simple tokenizer
201*/
202static const sqlite3_tokenizer_module simpleTokenizerModule = {
203 0,
204 simpleCreate,
205 simpleDestroy,
206 simpleOpen,
207 simpleClose,
208 simpleNext,
209};
210
211/*
212** Allocate a new simple tokenizer. Return a pointer to the new
213** tokenizer in *ppModule
214*/
215void sqlite3Fts1SimpleTokenizerModule(
216 sqlite3_tokenizer_module const**ppModule
217){
218 *ppModule = &simpleTokenizerModule;
219}
220
221#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS1) */