535 lines
15 KiB
C
535 lines
15 KiB
C
/*
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** 2007 May 6
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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** $Id: icu.c,v 1.7 2007/12/13 21:54:11 drh Exp $
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**
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** This file implements an integration between the ICU library
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** ("International Components for Unicode", an open-source library
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** for handling unicode data) and SQLite. The integration uses
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** ICU to provide the following to SQLite:
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**
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** * An implementation of the SQL regexp() function (and hence REGEXP
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** operator) using the ICU uregex_XX() APIs.
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**
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** * Implementations of the SQL scalar upper() and lower() functions
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** for case mapping.
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**
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** * Integration of ICU and SQLite collation sequences.
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**
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** * An implementation of the LIKE operator that uses ICU to
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** provide case-independent matching.
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*/
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#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_ICU)
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/* Include ICU headers */
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#include <unicode/utypes.h>
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#include <unicode/uregex.h>
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#include <unicode/ustring.h>
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#include <unicode/ucol.h>
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#include <assert.h>
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#ifndef SQLITE_CORE
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#include "sqlite3ext.h"
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SQLITE_EXTENSION_INIT1
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#else
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#include "sqlite3.h"
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#endif
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/*
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** Maximum length (in bytes) of the pattern in a LIKE or GLOB
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** operator.
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*/
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#ifndef SQLITE_MAX_LIKE_PATTERN_LENGTH
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# define SQLITE_MAX_LIKE_PATTERN_LENGTH 50000
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#endif
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/*
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** Version of sqlite3_free() that is always a function, never a macro.
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*/
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static void xFree(void *p){
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sqlite3_free(p);
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}
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/*
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** This lookup table is used to help decode the first byte of
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** a multi-byte UTF8 character. It is copied here from SQLite source
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** code file utf8.c.
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*/
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static const unsigned char icuUtf8Trans1[] = {
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0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
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0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
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0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
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0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
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0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
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0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
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0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
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0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
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};
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#define SQLITE_ICU_READ_UTF8(zIn, c) \
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c = *(zIn++); \
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if( c>=0xc0 ){ \
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c = icuUtf8Trans1[c-0xc0]; \
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while( (*zIn & 0xc0)==0x80 ){ \
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c = (c<<6) + (0x3f & *(zIn++)); \
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} \
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}
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#define SQLITE_ICU_SKIP_UTF8(zIn) \
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assert( *zIn ); \
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if( *(zIn++)>=0xc0 ){ \
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while( (*zIn & 0xc0)==0x80 ){zIn++;} \
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}
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/*
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** Compare two UTF-8 strings for equality where the first string is
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** a "LIKE" expression. Return true (1) if they are the same and
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** false (0) if they are different.
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*/
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static int icuLikeCompare(
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const uint8_t *zPattern, /* LIKE pattern */
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const uint8_t *zString, /* The UTF-8 string to compare against */
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const UChar32 uEsc /* The escape character */
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){
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static const int MATCH_ONE = (UChar32)'_';
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static const int MATCH_ALL = (UChar32)'%';
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int prevEscape = 0; /* True if the previous character was uEsc */
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while( 1 ){
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/* Read (and consume) the next character from the input pattern. */
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UChar32 uPattern;
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SQLITE_ICU_READ_UTF8(zPattern, uPattern);
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if( uPattern==0 ) break;
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/* There are now 4 possibilities:
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**
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** 1. uPattern is an unescaped match-all character "%",
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** 2. uPattern is an unescaped match-one character "_",
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** 3. uPattern is an unescaped escape character, or
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** 4. uPattern is to be handled as an ordinary character
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*/
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if( !prevEscape && uPattern==MATCH_ALL ){
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/* Case 1. */
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uint8_t c;
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/* Skip any MATCH_ALL or MATCH_ONE characters that follow a
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** MATCH_ALL. For each MATCH_ONE, skip one character in the
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** test string.
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*/
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while( (c=*zPattern) == MATCH_ALL || c == MATCH_ONE ){
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if( c==MATCH_ONE ){
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if( *zString==0 ) return 0;
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SQLITE_ICU_SKIP_UTF8(zString);
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}
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zPattern++;
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}
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if( *zPattern==0 ) return 1;
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while( *zString ){
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if( icuLikeCompare(zPattern, zString, uEsc) ){
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return 1;
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}
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SQLITE_ICU_SKIP_UTF8(zString);
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}
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return 0;
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}else if( !prevEscape && uPattern==MATCH_ONE ){
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/* Case 2. */
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if( *zString==0 ) return 0;
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SQLITE_ICU_SKIP_UTF8(zString);
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}else if( !prevEscape && uPattern==uEsc){
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/* Case 3. */
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prevEscape = 1;
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}else{
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/* Case 4. */
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UChar32 uString;
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SQLITE_ICU_READ_UTF8(zString, uString);
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uString = u_foldCase(uString, U_FOLD_CASE_DEFAULT);
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uPattern = u_foldCase(uPattern, U_FOLD_CASE_DEFAULT);
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if( uString!=uPattern ){
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return 0;
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}
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prevEscape = 0;
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}
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}
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return *zString==0;
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}
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/*
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** Implementation of the like() SQL function. This function implements
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** the build-in LIKE operator. The first argument to the function is the
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** pattern and the second argument is the string. So, the SQL statements:
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**
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** A LIKE B
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**
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** is implemented as like(B, A). If there is an escape character E,
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**
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** A LIKE B ESCAPE E
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**
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** is mapped to like(B, A, E).
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*/
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static void icuLikeFunc(
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sqlite3_context *context,
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int argc,
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sqlite3_value **argv
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){
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const unsigned char *zA = sqlite3_value_text(argv[0]);
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const unsigned char *zB = sqlite3_value_text(argv[1]);
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UChar32 uEsc = 0;
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/* Limit the length of the LIKE or GLOB pattern to avoid problems
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** of deep recursion and N*N behavior in patternCompare().
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*/
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if( sqlite3_value_bytes(argv[0])>SQLITE_MAX_LIKE_PATTERN_LENGTH ){
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sqlite3_result_error(context, "LIKE or GLOB pattern too complex", -1);
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return;
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}
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if( argc==3 ){
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/* The escape character string must consist of a single UTF-8 character.
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** Otherwise, return an error.
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*/
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int nE= sqlite3_value_bytes(argv[2]);
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const unsigned char *zE = sqlite3_value_text(argv[2]);
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int i = 0;
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if( zE==0 ) return;
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U8_NEXT(zE, i, nE, uEsc);
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if( i!=nE){
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sqlite3_result_error(context,
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"ESCAPE expression must be a single character", -1);
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return;
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}
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}
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if( zA && zB ){
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sqlite3_result_int(context, icuLikeCompare(zA, zB, uEsc));
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}
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}
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/*
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** This function is called when an ICU function called from within
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** the implementation of an SQL scalar function returns an error.
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**
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** The scalar function context passed as the first argument is
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** loaded with an error message based on the following two args.
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*/
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static void icuFunctionError(
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sqlite3_context *pCtx, /* SQLite scalar function context */
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const char *zName, /* Name of ICU function that failed */
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UErrorCode e /* Error code returned by ICU function */
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){
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char zBuf[128];
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sqlite3_snprintf(128, zBuf, "ICU error: %s(): %s", zName, u_errorName(e));
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zBuf[127] = '\0';
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sqlite3_result_error(pCtx, zBuf, -1);
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}
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/*
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** Function to delete compiled regexp objects. Registered as
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** a destructor function with sqlite3_set_auxdata().
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*/
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static void icuRegexpDelete(void *p){
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URegularExpression *pExpr = (URegularExpression *)p;
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uregex_close(pExpr);
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}
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/*
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** Implementation of SQLite REGEXP operator. This scalar function takes
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** two arguments. The first is a regular expression pattern to compile
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** the second is a string to match against that pattern. If either
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** argument is an SQL NULL, then NULL Is returned. Otherwise, the result
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** is 1 if the string matches the pattern, or 0 otherwise.
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**
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** SQLite maps the regexp() function to the regexp() operator such
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** that the following two are equivalent:
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**
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** zString REGEXP zPattern
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** regexp(zPattern, zString)
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**
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** Uses the following ICU regexp APIs:
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**
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** uregex_open()
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** uregex_matches()
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** uregex_close()
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*/
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static void icuRegexpFunc(sqlite3_context *p, int nArg, sqlite3_value **apArg){
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UErrorCode status = U_ZERO_ERROR;
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URegularExpression *pExpr;
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UBool res;
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const UChar *zString = sqlite3_value_text16(apArg[1]);
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(void)nArg; /* Unused parameter */
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/* If the left hand side of the regexp operator is NULL,
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** then the result is also NULL.
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*/
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if( !zString ){
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return;
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}
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pExpr = sqlite3_get_auxdata(p, 0);
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if( !pExpr ){
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const UChar *zPattern = sqlite3_value_text16(apArg[0]);
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if( !zPattern ){
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return;
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}
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pExpr = uregex_open(zPattern, -1, 0, 0, &status);
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if( U_SUCCESS(status) ){
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sqlite3_set_auxdata(p, 0, pExpr, icuRegexpDelete);
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}else{
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assert(!pExpr);
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icuFunctionError(p, "uregex_open", status);
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return;
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}
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}
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/* Configure the text that the regular expression operates on. */
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uregex_setText(pExpr, zString, -1, &status);
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if( !U_SUCCESS(status) ){
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icuFunctionError(p, "uregex_setText", status);
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return;
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}
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/* Attempt the match */
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res = uregex_matches(pExpr, 0, &status);
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if( !U_SUCCESS(status) ){
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icuFunctionError(p, "uregex_matches", status);
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return;
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}
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/* Set the text that the regular expression operates on to a NULL
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** pointer. This is not really necessary, but it is tidier than
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** leaving the regular expression object configured with an invalid
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** pointer after this function returns.
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*/
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uregex_setText(pExpr, 0, 0, &status);
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/* Return 1 or 0. */
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sqlite3_result_int(p, res ? 1 : 0);
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}
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/*
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** Implementations of scalar functions for case mapping - upper() and
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** lower(). Function upper() converts its input to upper-case (ABC).
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** Function lower() converts to lower-case (abc).
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**
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** ICU provides two types of case mapping, "general" case mapping and
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** "language specific". Refer to ICU documentation for the differences
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** between the two.
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**
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** To utilise "general" case mapping, the upper() or lower() scalar
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** functions are invoked with one argument:
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**
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** upper('ABC') -> 'abc'
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** lower('abc') -> 'ABC'
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**
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** To access ICU "language specific" case mapping, upper() or lower()
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** should be invoked with two arguments. The second argument is the name
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** of the locale to use. Passing an empty string ("") or SQL NULL value
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** as the second argument is the same as invoking the 1 argument version
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** of upper() or lower().
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**
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** lower('I', 'en_us') -> 'i'
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** lower('I', 'tr_tr') -> 'ı' (small dotless i)
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**
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** http://www.icu-project.org/userguide/posix.html#case_mappings
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*/
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static void icuCaseFunc16(sqlite3_context *p, int nArg, sqlite3_value **apArg){
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const UChar *zInput;
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UChar *zOutput;
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int nInput;
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int nOutput;
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UErrorCode status = U_ZERO_ERROR;
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const char *zLocale = 0;
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assert(nArg==1 || nArg==2);
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if( nArg==2 ){
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zLocale = (const char *)sqlite3_value_text(apArg[1]);
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}
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zInput = sqlite3_value_text16(apArg[0]);
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if( !zInput ){
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return;
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}
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nInput = sqlite3_value_bytes16(apArg[0]);
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nOutput = nInput * 2 + 2;
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zOutput = sqlite3_malloc(nOutput);
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if( !zOutput ){
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return;
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}
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if( sqlite3_user_data(p) ){
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u_strToUpper(zOutput, nOutput/2, zInput, nInput/2, zLocale, &status);
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}else{
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u_strToLower(zOutput, nOutput/2, zInput, nInput/2, zLocale, &status);
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}
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if( !U_SUCCESS(status) ){
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icuFunctionError(p, "u_strToLower()/u_strToUpper", status);
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return;
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}
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sqlite3_result_text16(p, zOutput, -1, xFree);
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}
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/*
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** Collation sequence destructor function. The pCtx argument points to
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** a UCollator structure previously allocated using ucol_open().
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*/
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static void icuCollationDel(void *pCtx){
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UCollator *p = (UCollator *)pCtx;
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ucol_close(p);
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}
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/*
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** Collation sequence comparison function. The pCtx argument points to
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** a UCollator structure previously allocated using ucol_open().
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*/
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static int icuCollationColl(
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void *pCtx,
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int nLeft,
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const void *zLeft,
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int nRight,
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const void *zRight
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){
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UCollationResult res;
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UCollator *p = (UCollator *)pCtx;
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res = ucol_strcoll(p, (UChar *)zLeft, nLeft/2, (UChar *)zRight, nRight/2);
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switch( res ){
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case UCOL_LESS: return -1;
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case UCOL_GREATER: return +1;
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case UCOL_EQUAL: return 0;
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}
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assert(!"Unexpected return value from ucol_strcoll()");
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return 0;
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}
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/*
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** Implementation of the scalar function icu_load_collation().
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**
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** This scalar function is used to add ICU collation based collation
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** types to an SQLite database connection. It is intended to be called
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** as follows:
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**
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** SELECT icu_load_collation(<locale>, <collation-name>);
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**
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** Where <locale> is a string containing an ICU locale identifier (i.e.
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** "en_AU", "tr_TR" etc.) and <collation-name> is the name of the
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** collation sequence to create.
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*/
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static void icuLoadCollation(
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sqlite3_context *p,
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int nArg,
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sqlite3_value **apArg
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){
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sqlite3 *db = (sqlite3 *)sqlite3_user_data(p);
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UErrorCode status = U_ZERO_ERROR;
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const char *zLocale; /* Locale identifier - (eg. "jp_JP") */
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const char *zName; /* SQL Collation sequence name (eg. "japanese") */
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UCollator *pUCollator; /* ICU library collation object */
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int rc; /* Return code from sqlite3_create_collation_x() */
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assert(nArg==2);
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(void)nArg; /* Unused parameter */
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zLocale = (const char *)sqlite3_value_text(apArg[0]);
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zName = (const char *)sqlite3_value_text(apArg[1]);
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if( !zLocale || !zName ){
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return;
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}
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pUCollator = ucol_open(zLocale, &status);
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if( !U_SUCCESS(status) ){
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icuFunctionError(p, "ucol_open", status);
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return;
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}
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assert(p);
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rc = sqlite3_create_collation_v2(db, zName, SQLITE_UTF16, (void *)pUCollator,
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icuCollationColl, icuCollationDel
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);
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if( rc!=SQLITE_OK ){
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ucol_close(pUCollator);
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sqlite3_result_error(p, "Error registering collation function", -1);
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}
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}
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/*
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** Register the ICU extension functions with database db.
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*/
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int sqlite3IcuInit(sqlite3 *db){
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struct IcuScalar {
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const char *zName; /* Function name */
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int nArg; /* Number of arguments */
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int enc; /* Optimal text encoding */
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void *pContext; /* sqlite3_user_data() context */
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void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
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} scalars[] = {
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{"regexp", 2, SQLITE_ANY, 0, icuRegexpFunc},
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{"lower", 1, SQLITE_UTF16, 0, icuCaseFunc16},
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{"lower", 2, SQLITE_UTF16, 0, icuCaseFunc16},
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{"upper", 1, SQLITE_UTF16, (void*)1, icuCaseFunc16},
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{"upper", 2, SQLITE_UTF16, (void*)1, icuCaseFunc16},
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{"lower", 1, SQLITE_UTF8, 0, icuCaseFunc16},
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{"lower", 2, SQLITE_UTF8, 0, icuCaseFunc16},
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{"upper", 1, SQLITE_UTF8, (void*)1, icuCaseFunc16},
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{"upper", 2, SQLITE_UTF8, (void*)1, icuCaseFunc16},
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||
|
||
{"like", 2, SQLITE_UTF8, 0, icuLikeFunc},
|
||
{"like", 3, SQLITE_UTF8, 0, icuLikeFunc},
|
||
|
||
{"icu_load_collation", 2, SQLITE_UTF8, (void*)db, icuLoadCollation},
|
||
};
|
||
|
||
int rc = SQLITE_OK;
|
||
int i;
|
||
|
||
for(i=0; rc==SQLITE_OK && i<(int)(sizeof(scalars)/sizeof(scalars[0])); i++){
|
||
struct IcuScalar *p = &scalars[i];
|
||
rc = sqlite3_create_function(
|
||
db, p->zName, p->nArg, p->enc, p->pContext, p->xFunc, 0, 0
|
||
);
|
||
}
|
||
|
||
return rc;
|
||
}
|
||
|
||
#if !SQLITE_CORE
|
||
#ifdef _WIN32
|
||
__declspec(dllexport)
|
||
#endif
|
||
int sqlite3_icu_init(
|
||
sqlite3 *db,
|
||
char **pzErrMsg,
|
||
const sqlite3_api_routines *pApi
|
||
){
|
||
SQLITE_EXTENSION_INIT2(pApi)
|
||
return sqlite3IcuInit(db);
|
||
}
|
||
#endif
|
||
|
||
#endif
|