/*
** 2012 May 24
**
** 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.
**
******************************************************************************
**
** Implementation of the "unicode" full-text-search tokenizer.
*/
#ifdef SQLITE_ENABLE_FTS4_UNICODE61
#include "fts3Int.h"
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "fts3_tokenizer.h"
/*
** The following two macros - READ_UTF8 and WRITE_UTF8 - have been copied
** from the sqlite3 source file utf.c. If this file is compiled as part
** of the amalgamation, they are not required.
*/
#ifndef SQLITE_AMALGAMATION
static const unsigned char sqlite3Utf8Trans1[] = {
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
};
#define READ_UTF8(zIn, zTerm, c) \
c = *(zIn++); \
if( c>=0xc0 ){ \
c = sqlite3Utf8Trans1[c-0xc0]; \
while( zIn!=zTerm && (*zIn & 0xc0)==0x80 ){ \
c = (c<<6) + (0x3f & *(zIn++)); \
} \
if( c<0x80 \
|| (c&0xFFFFF800)==0xD800 \
|| (c&0xFFFFFFFE)==0xFFFE ){ c = 0xFFFD; } \
}
#define WRITE_UTF8(zOut, c) { \
if( c<0x00080 ){ \
*zOut++ = (u8)(c&0xFF); \
} \
else if( c<0x00800 ){ \
*zOut++ = 0xC0 + (u8)((c>>6)&0x1F); \
*zOut++ = 0x80 + (u8)(c & 0x3F); \
} \
else if( c<0x10000 ){ \
*zOut++ = 0xE0 + (u8)((c>>12)&0x0F); \
*zOut++ = 0x80 + (u8)((c>>6) & 0x3F); \
*zOut++ = 0x80 + (u8)(c & 0x3F); \
}else{ \
*zOut++ = 0xF0 + (u8)((c>>18) & 0x07); \
*zOut++ = 0x80 + (u8)((c>>12) & 0x3F); \
*zOut++ = 0x80 + (u8)((c>>6) & 0x3F); \
*zOut++ = 0x80 + (u8)(c & 0x3F); \
} \
}
#endif /* ifndef SQLITE_AMALGAMATION */
typedef struct unicode_tokenizer unicode_tokenizer;
typedef struct unicode_cursor unicode_cursor;
struct unicode_tokenizer {
sqlite3_tokenizer base;
int bRemoveDiacritic;
int nException;
int *aiException;
};
struct unicode_cursor {
sqlite3_tokenizer_cursor base;
const unsigned char *aInput; /* Input text being tokenized */
int nInput; /* Size of aInput[] in bytes */
int iOff; /* Current offset within aInput[] */
int iToken; /* Index of next token to be returned */
char *zToken; /* storage for current token */
int nAlloc; /* space allocated at zToken */
};
/*
** Destroy a tokenizer allocated by unicodeCreate().
*/
static int unicodeDestroy(sqlite3_tokenizer *pTokenizer){
if( pTokenizer ){
unicode_tokenizer *p = (unicode_tokenizer *)pTokenizer;
sqlite3_free(p->aiException);
sqlite3_free(p);
}
return SQLITE_OK;
}
/*
** As part of a tokenchars= or separators= option, the CREATE VIRTUAL TABLE
** statement has specified that the tokenizer for this table shall consider
** all characters in string zIn/nIn to be separators (if bAlnum==0) or
** token characters (if bAlnum==1).
**
** For each codepoint in the zIn/nIn string, this function checks if the
** sqlite3FtsUnicodeIsalnum() function already returns the desired result.
** If so, no action is taken. Otherwise, the codepoint is added to the
** unicode_tokenizer.aiException[] array. For the purposes of tokenization,
** the return value of sqlite3FtsUnicodeIsalnum() is inverted for all
** codepoints in the aiException[] array.
**
** If a standalone diacritic mark (one that sqlite3FtsUnicodeIsdiacritic()
** identifies as a diacritic) occurs in the zIn/nIn string it is ignored.
** It is not possible to change the behavior of the tokenizer with respect
** to these codepoints.
*/
static int unicodeAddExceptions(
unicode_tokenizer *p, /* Tokenizer to add exceptions to */
int bAlnum, /* Replace Isalnum() return value with this */
const char *zIn, /* Array of characters to make exceptions */
int nIn /* Length of z in bytes */
){
const unsigned char *z = (const unsigned char *)zIn;
const unsigned char *zTerm = &z[nIn];
int iCode;
int nEntry = 0;
assert( bAlnum==0 || bAlnum==1 );
while( z<zTerm ){
READ_UTF8(z, zTerm, iCode);
assert( (sqlite3FtsUnicodeIsalnum(iCode) & 0xFFFFFFFE)==0 );
if( sqlite3FtsUnicodeIsalnum(iCode)!=bAlnum
&& sqlite3FtsUnicodeIsdiacritic(iCode)==0
){
nEntry++;
}
}
if( nEntry ){
int *aNew; /* New aiException[] array */
int nNew; /* Number of valid entries in array aNew[] */
aNew = sqlite3_realloc(p->aiException, (p->nException+nEntry)*sizeof(int));
if( aNew==0 ) return SQLITE_NOMEM;
nNew = p->nException;
z = (const unsigned char *)zIn;
while( z<zTerm ){
READ_UTF8(z, zTerm, iCode);
if( sqlite3FtsUnicodeIsalnum(iCode)!=bAlnum
&& sqlite3FtsUnicodeIsdiacritic(iCode)==0
){
int i, j;
for(i=0; i<nNew && aNew[i]<iCode; i++);
for(j=nNew; j>i; j--) aNew[j] = aNew[j-1];
aNew[i] = iCode;
nNew++;
}
}
p->aiException = aNew;
p->nException = nNew;
}
return SQLITE_OK;
}
/*
** Return true if the p->aiException[] array contains the value iCode.
*/
static int unicodeIsException(unicode_tokenizer *p, int iCode){
if( p->nException>0 ){
int *a = p->aiException;
int iLo = 0;
int iHi = p->nException-1;
while( iHi>=iLo ){
int iTest = (iHi + iLo) / 2;
if( iCode==a[iTest] ){
return 1;
}else if( iCode>a[iTest] ){
iLo = iTest+1;
}else{
iHi = iTest-1;
}
}
}
return 0;
}
/*
** Return true if, for the purposes of tokenization, codepoint iCode is
** considered a token character (not a separator).
*/
static int unicodeIsAlnum(unicode_tokenizer *p, int iCode){
assert( (sqlite3FtsUnicodeIsalnum(iCode) & 0xFFFFFFFE)==0 );
return sqlite3FtsUnicodeIsalnum(iCode) ^ unicodeIsException(p, iCode);
}
/*
** Create a new tokenizer instance.
*/
static int unicodeCreate(
int nArg, /* Size of array argv[] */
const char * const *azArg, /* Tokenizer creation arguments */
sqlite3_tokenizer **pp /* OUT: New tokenizer handle */
){
unicode_tokenizer *pNew; /* New tokenizer object */
int i;
int rc = SQLITE_OK;
pNew = (unicode_tokenizer *) sqlite3_malloc(sizeof(unicode_tokenizer));
if( pNew==NULL ) return SQLITE_NOMEM;
memset(pNew, 0, sizeof(unicode_tokenizer));
pNew->bRemoveDiacritic = 1;
for(i=0; rc==SQLITE_OK && i<nArg; i++){
const char *z = azArg[i];
int n = strlen(z);
if( n==19 && memcmp("remove_diacritics=1", z, 19)==0 ){
pNew->bRemoveDiacritic = 1;
}
else if( n==19 && memcmp("remove_diacritics=0", z, 19)==0 ){
pNew->bRemoveDiacritic = 0;
}
else if( n>=11 && memcmp("tokenchars=", z, 11)==0 ){
rc = unicodeAddExceptions(pNew, 1, &z[11], n-11);
}
else if( n>=11 && memcmp("separators=", z, 11)==0 ){
rc = unicodeAddExceptions(pNew, 0, &z[11], n-11);
}
else{
/* Unrecognized argument */
rc = SQLITE_ERROR;
}
}
if( rc!=SQLITE_OK ){
unicodeDestroy((sqlite3_tokenizer *)pNew);
pNew = 0;
}
*pp = (sqlite3_tokenizer *)pNew;
return rc;
}
/*
** 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 unicodeOpen(
sqlite3_tokenizer *p, /* The tokenizer */
const char *aInput, /* Input string */
int nInput, /* Size of string aInput in bytes */
sqlite3_tokenizer_cursor **pp /* OUT: New cursor object */
){
unicode_cursor *pCsr;
pCsr = (unicode_cursor *)sqlite3_malloc(sizeof(unicode_cursor));
if( pCsr==0 ){
return SQLITE_NOMEM;
}
memset(pCsr, 0, sizeof(unicode_cursor));
pCsr->aInput = (const unsigned char *)aInput;
if( aInput==0 ){
pCsr->nInput = 0;
}else if( nInput<0 ){
pCsr->nInput = (int)strlen(aInput);
}else{
pCsr->nInput = nInput;
}
*pp = &pCsr->base;
UNUSED_PARAMETER(p);
return SQLITE_OK;
}
/*
** Close a tokenization cursor previously opened by a call to
** simpleOpen() above.
*/
static int unicodeClose(sqlite3_tokenizer_cursor *pCursor){
unicode_cursor *pCsr = (unicode_cursor *) pCursor;
sqlite3_free(pCsr->zToken);
sqlite3_free(pCsr);
return SQLITE_OK;
}
/*
** Extract the next token from a tokenization cursor. The cursor must
** have been opened by a prior call to simpleOpen().
*/
static int unicodeNext(
sqlite3_tokenizer_cursor *pC, /* Cursor returned by simpleOpen */
const char **paToken, /* OUT: Token text */
int *pnToken, /* OUT: Number of bytes at *paToken */
int *piStart, /* OUT: Starting offset of token */
int *piEnd, /* OUT: Ending offset of token */
int *piPos /* OUT: Position integer of token */
){
unicode_cursor *pCsr = (unicode_cursor *)pC;
unicode_tokenizer *p = ((unicode_tokenizer *)pCsr->base.pTokenizer);
int iCode;
char *zOut;
const unsigned char *z = &pCsr->aInput[pCsr->iOff];
const unsigned char *zStart = z;
const unsigned char *zEnd;
const unsigned char *zTerm = &pCsr->aInput[pCsr->nInput];
/* Scan past any delimiter characters before the start of the next token.
** Return SQLITE_DONE early if this takes us all the way to the end of
** the input. */
while( z<zTerm ){
READ_UTF8(z, zTerm, iCode);
if( unicodeIsAlnum(p, iCode) ) break;
zStart = z;
}
if( zStart>=zTerm ) return SQLITE_DONE;
zOut = pCsr->zToken;
do {
int iOut;
/* Grow the output buffer if required. */
if( (zOut-pCsr->zToken)>=(pCsr->nAlloc-4) ){
char *zNew = sqlite3_realloc(pCsr->zToken, pCsr->nAlloc+64);
if( !zNew ) return SQLITE_NOMEM;
zOut = &zNew[zOut - pCsr->zToken];
pCsr->zToken = zNew;
pCsr->nAlloc += 64;
}
/* Write the folded case of the last character read to the output */
zEnd = z;
iOut = sqlite3FtsUnicodeFold(iCode, p->bRemoveDiacritic);
if( iOut ){
WRITE_UTF8(zOut, iOut);
}
/* If the cursor is not at EOF, read the next character */
if( z>=zTerm ) break;
READ_UTF8(z, zTerm, iCode);
}while( unicodeIsAlnum(p, iCode)
|| sqlite3FtsUnicodeIsdiacritic(iCode)
);
/* Set the output variables and return. */
pCsr->iOff = (z - pCsr->aInput);
*paToken = pCsr->zToken;
*pnToken = zOut - pCsr->zToken;
*piStart = (zStart - pCsr->aInput);
*piEnd = (zEnd - pCsr->aInput);
*piPos = pCsr->iToken++;
return SQLITE_OK;
}
/*
** Set *ppModule to a pointer to the sqlite3_tokenizer_module
** structure for the unicode tokenizer.
*/
void sqlite3Fts3UnicodeTokenizer(sqlite3_tokenizer_module const **ppModule){
static const sqlite3_tokenizer_module module = {
0,
unicodeCreate,
unicodeDestroy,
unicodeOpen,
unicodeClose,
unicodeNext,
0,
};
*ppModule = &module;
}
#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
#endif /* ifndef SQLITE_ENABLE_FTS4_UNICODE61 */