/*
** 2007 June 22
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
** This file implements a tokenizer for fts3 based on the ICU library.
*/
#include "fts3Int.h"
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
#ifdef SQLITE_ENABLE_ICU
#include <assert.h>
#include <string.h>
#include "fts3_tokenizer.h"
#include <unicode/ubrk.h>
#include <unicode/ucol.h>
#include <unicode/ustring.h>
#include <unicode/utf16.h>
typedef struct IcuTokenizer IcuTokenizer;
typedef struct IcuCursor IcuCursor;
struct IcuTokenizer {
sqlite3_tokenizer base;
char *zLocale;
};
struct IcuCursor {
sqlite3_tokenizer_cursor base;
UBreakIterator *pIter; /* ICU break-iterator object */
int nChar; /* Number of UChar elements in pInput */
UChar *aChar; /* Copy of input using utf-16 encoding */
int *aOffset; /* Offsets of each character in utf-8 input */
int nBuffer;
char *zBuffer;
int iToken;
};
/*
** Create a new tokenizer instance.
*/
static int icuCreate(
int argc, /* Number of entries in argv[] */
const char * const *argv, /* Tokenizer creation arguments */
sqlite3_tokenizer **ppTokenizer /* OUT: Created tokenizer */
){
IcuTokenizer *p;
int n = 0;
if( argc>0 ){
n = strlen(argv[0])+1;
}
p = (IcuTokenizer *)sqlite3_malloc(sizeof(IcuTokenizer)+n);
if( !p ){
return SQLITE_NOMEM;
}
memset(p, 0, sizeof(IcuTokenizer));
if( n ){
p->zLocale = (char *)&p[1];
memcpy(p->zLocale, argv[0], n);
}
*ppTokenizer = (sqlite3_tokenizer *)p;
return SQLITE_OK;
}
/*
** Destroy a tokenizer
*/
static int icuDestroy(sqlite3_tokenizer *pTokenizer){
IcuTokenizer *p = (IcuTokenizer *)pTokenizer;
sqlite3_free(p);
return SQLITE_OK;
}
/*
** Prepare to begin tokenizing a particular string. The input
** string to be tokenized is pInput[0..nBytes-1]. A cursor
** used to incrementally tokenize this string is returned in
** *ppCursor.
*/
static int icuOpen(
sqlite3_tokenizer *pTokenizer, /* The tokenizer */
const char *zInput, /* Input string */
int nInput, /* Length of zInput in bytes */
sqlite3_tokenizer_cursor **ppCursor /* OUT: Tokenization cursor */
){
IcuTokenizer *p = (IcuTokenizer *)pTokenizer;
IcuCursor *pCsr;
const int32_t opt = U_FOLD_CASE_DEFAULT;
UErrorCode status = U_ZERO_ERROR;
int nChar;
UChar32 c;
int iInput = 0;
int iOut = 0;
*ppCursor = 0;
if( zInput==0 ){
nInput = 0;
zInput = "";
}else if( nInput<0 ){
nInput = strlen(zInput);
}
nChar = nInput+1;
pCsr = (IcuCursor *)sqlite3_malloc(
sizeof(IcuCursor) + /* IcuCursor */
((nChar+3)&~3) * sizeof(UChar) + /* IcuCursor.aChar[] */
(nChar+1) * sizeof(int) /* IcuCursor.aOffset[] */
);
if( !pCsr ){
return SQLITE_NOMEM;
}
memset(pCsr, 0, sizeof(IcuCursor));
pCsr->aChar = (UChar *)&pCsr[1];
pCsr->aOffset = (int *)&pCsr->aChar[(nChar+3)&~3];
pCsr->aOffset[iOut] = iInput;
U8_NEXT(zInput, iInput, nInput, c);
while( c>0 ){
int isError = 0;
c = u_foldCase(c, opt);
U16_APPEND(pCsr->aChar, iOut, nChar, c, isError);
if( isError ){
sqlite3_free(pCsr);
return SQLITE_ERROR;
}
pCsr->aOffset[iOut] = iInput;
if( iInput<nInput ){
U8_NEXT(zInput, iInput, nInput, c);
}else{
c = 0;
}
}
pCsr->pIter = ubrk_open(UBRK_WORD, p->zLocale, pCsr->aChar, iOut, &status);
if( !U_SUCCESS(status) ){
sqlite3_free(pCsr);
return SQLITE_ERROR;
}
pCsr->nChar = iOut;
ubrk_first(pCsr->pIter);
*ppCursor = (sqlite3_tokenizer_cursor *)pCsr;
return SQLITE_OK;
}
/*
** Close a tokenization cursor previously opened by a call to icuOpen().
*/
static int icuClose(sqlite3_tokenizer_cursor *pCursor){
IcuCursor *pCsr = (IcuCursor *)pCursor;
ubrk_close(pCsr->pIter);
sqlite3_free(pCsr->zBuffer);
sqlite3_free(pCsr);
return SQLITE_OK;
}
/*
** Extract the next token from a tokenization cursor.
*/
static int icuNext(
sqlite3_tokenizer_cursor *pCursor, /* Cursor returned by simpleOpen */
const char **ppToken, /* OUT: *ppToken is the token text */
int *pnBytes, /* OUT: Number of bytes in token */
int *piStartOffset, /* OUT: Starting offset of token */
int *piEndOffset, /* OUT: Ending offset of token */
int *piPosition /* OUT: Position integer of token */
){
IcuCursor *pCsr = (IcuCursor *)pCursor;
int iStart = 0;
int iEnd = 0;
int nByte = 0;
while( iStart==iEnd ){
UChar32 c;
iStart = ubrk_current(pCsr->pIter);
iEnd = ubrk_next(pCsr->pIter);
if( iEnd==UBRK_DONE ){
return SQLITE_DONE;
}
while( iStart<iEnd ){
int iWhite = iStart;
U16_NEXT(pCsr->aChar, iWhite, pCsr->nChar, c);
if( u_isspace(c) ){
iStart = iWhite;
}else{
break;
}
}
assert(iStart<=iEnd);
}
do {
UErrorCode status = U_ZERO_ERROR;
if( nByte ){
char *zNew = sqlite3_realloc(pCsr->zBuffer, nByte);
if( !zNew ){
return SQLITE_NOMEM;
}
pCsr->zBuffer = zNew;
pCsr->nBuffer = nByte;
}
u_strToUTF8(
pCsr->zBuffer, pCsr->nBuffer, &nByte, /* Output vars */
&pCsr->aChar[iStart], iEnd-iStart, /* Input vars */
&status /* Output success/failure */
);
} while( nByte>pCsr->nBuffer );
*ppToken = pCsr->zBuffer;
*pnBytes = nByte;
*piStartOffset = pCsr->aOffset[iStart];
*piEndOffset = pCsr->aOffset[iEnd];
*piPosition = pCsr->iToken++;
return SQLITE_OK;
}
/*
** The set of routines that implement the simple tokenizer
*/
static const sqlite3_tokenizer_module icuTokenizerModule = {
0, /* iVersion */
icuCreate, /* xCreate */
icuDestroy, /* xCreate */
icuOpen, /* xOpen */
icuClose, /* xClose */
icuNext, /* xNext */
0, /* xLanguageid */
};
/*
** Set *ppModule to point at the implementation of the ICU tokenizer.
*/
void sqlite3Fts3IcuTokenizerModule(
sqlite3_tokenizer_module const**ppModule
){
*ppModule = &icuTokenizerModule;
}
#endif /* defined(SQLITE_ENABLE_ICU) */
#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */