?? utf.c
字號:
/*
** 2004 April 13
**
** 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 contains routines used to translate between UTF-8,
** UTF-16, UTF-16BE, and UTF-16LE.
**
** $Id: utf.c,v 1.23 2006/10/12 21:34:22 rmsimpson Exp $
**
** Notes on UTF-8:
**
** Byte-0 Byte-1 Byte-2 Byte-3 Value
** 0xxxxxxx 00000000 00000000 0xxxxxxx
** 110yyyyy 10xxxxxx 00000000 00000yyy yyxxxxxx
** 1110zzzz 10yyyyyy 10xxxxxx 00000000 zzzzyyyy yyxxxxxx
** 11110uuu 10uuzzzz 10yyyyyy 10xxxxxx 000uuuuu zzzzyyyy yyxxxxxx
**
**
** Notes on UTF-16: (with wwww+1==uuuuu)
**
** Word-0 Word-1 Value
** 110110ww wwzzzzyy 110111yy yyxxxxxx 000uuuuu zzzzyyyy yyxxxxxx
** zzzzyyyy yyxxxxxx 00000000 zzzzyyyy yyxxxxxx
**
**
** BOM or Byte Order Mark:
** 0xff 0xfe little-endian utf-16 follows
** 0xfe 0xff big-endian utf-16 follows
**
**
** Handling of malformed strings:
**
** SQLite accepts and processes malformed strings without an error wherever
** possible. However this is not possible when converting between UTF-8 and
** UTF-16.
**
** When converting malformed UTF-8 strings to UTF-16, one instance of the
** replacement character U+FFFD for each byte that cannot be interpeted as
** part of a valid unicode character.
**
** When converting malformed UTF-16 strings to UTF-8, one instance of the
** replacement character U+FFFD for each pair of bytes that cannot be
** interpeted as part of a valid unicode character.
** This file contains the following public routines:
**
** sqlite3VdbeMemTranslate() - Translate the encoding used by a Mem* string.
** sqlite3VdbeMemHandleBom() - Handle byte-order-marks in UTF16 Mem* strings.
** sqlite3utf16ByteLen() - Calculate byte-length of a void* UTF16 string.
** sqlite3utf8CharLen() - Calculate char-length of a char* UTF8 string.
** sqlite3utf8LikeCompare() - Do a LIKE match given two UTF8 char* strings.
**
*/
#include "sqliteInt.h"
#include <assert.h>
#include "vdbeInt.h"
/*
** This table maps from the first byte of a UTF-8 character to the number
** of trailing bytes expected. A value '255' indicates that the table key
** is not a legal first byte for a UTF-8 character.
*/
static const u8 xtra_utf8_bytes[256] = {
/* 0xxxxxxx */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 10wwwwww */
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
/* 110yyyyy */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
/* 1110zzzz */
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
/* 11110yyy */
3, 3, 3, 3, 3, 3, 3, 3, 255, 255, 255, 255, 255, 255, 255, 255,
};
/*
** This table maps from the number of trailing bytes in a UTF-8 character
** to an integer constant that is effectively calculated for each character
** read by a naive implementation of a UTF-8 character reader. The code
** in the READ_UTF8 macro explains things best.
*/
static const int xtra_utf8_bits[4] = {
0,
12416, /* (0xC0 << 6) + (0x80) */
925824, /* (0xE0 << 12) + (0x80 << 6) + (0x80) */
63447168 /* (0xF0 << 18) + (0x80 << 12) + (0x80 << 6) + 0x80 */
};
#define READ_UTF8(zIn, c) { \
int xtra; \
c = *(zIn)++; \
xtra = xtra_utf8_bytes[c]; \
switch( xtra ){ \
case 255: c = (int)0xFFFD; break; \
case 3: c = (c<<6) + *(zIn)++; \
case 2: c = (c<<6) + *(zIn)++; \
case 1: c = (c<<6) + *(zIn)++; \
c -= xtra_utf8_bits[xtra]; \
} \
}
int sqlite3ReadUtf8(const unsigned char *z){
int c;
READ_UTF8(z, c);
return c;
}
#define SKIP_UTF8(zIn) { \
zIn += (xtra_utf8_bytes[*(u8 *)zIn] + 1); \
}
#define WRITE_UTF8(zOut, c) { \
if( c<0x00080 ){ \
*zOut++ = (c&0xFF); \
} \
else if( c<0x00800 ){ \
*zOut++ = 0xC0 + ((c>>6)&0x1F); \
*zOut++ = 0x80 + (c & 0x3F); \
} \
else if( c<0x10000 ){ \
*zOut++ = 0xE0 + ((c>>12)&0x0F); \
*zOut++ = 0x80 + ((c>>6) & 0x3F); \
*zOut++ = 0x80 + (c & 0x3F); \
}else{ \
*zOut++ = 0xF0 + ((c>>18) & 0x07); \
*zOut++ = 0x80 + ((c>>12) & 0x3F); \
*zOut++ = 0x80 + ((c>>6) & 0x3F); \
*zOut++ = 0x80 + (c & 0x3F); \
} \
}
#define WRITE_UTF16LE(zOut, c) { \
if( c<=0xFFFF ){ \
*zOut++ = (c&0x00FF); \
*zOut++ = ((c>>8)&0x00FF); \
}else{ \
*zOut++ = (((c>>10)&0x003F) + (((c-0x10000)>>10)&0x00C0)); \
*zOut++ = (0x00D8 + (((c-0x10000)>>18)&0x03)); \
*zOut++ = (c&0x00FF); \
*zOut++ = (0x00DC + ((c>>8)&0x03)); \
} \
}
#define WRITE_UTF16BE(zOut, c) { \
if( c<=0xFFFF ){ \
*zOut++ = ((c>>8)&0x00FF); \
*zOut++ = (c&0x00FF); \
}else{ \
*zOut++ = (0x00D8 + (((c-0x10000)>>18)&0x03)); \
*zOut++ = (((c>>10)&0x003F) + (((c-0x10000)>>10)&0x00C0)); \
*zOut++ = (0x00DC + ((c>>8)&0x03)); \
*zOut++ = (c&0x00FF); \
} \
}
#define READ_UTF16LE(zIn, c){ \
c = (*zIn++); \
c += ((*zIn++)<<8); \
if( c>=0xD800 && c<=0xE000 ){ \
int c2 = (*zIn++); \
c2 += ((*zIn++)<<8); \
c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10); \
} \
}
#define READ_UTF16BE(zIn, c){ \
c = ((*zIn++)<<8); \
c += (*zIn++); \
if( c>=0xD800 && c<=0xE000 ){ \
int c2 = ((*zIn++)<<8); \
c2 += (*zIn++); \
c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10); \
} \
}
#define SKIP_UTF16BE(zIn){ \
if( *zIn>=0xD8 && (*zIn<0xE0 || (*zIn==0xE0 && *(zIn+1)==0x00)) ){ \
zIn += 4; \
}else{ \
zIn += 2; \
} \
}
#define SKIP_UTF16LE(zIn){ \
zIn++; \
if( *zIn>=0xD8 && (*zIn<0xE0 || (*zIn==0xE0 && *(zIn-1)==0x00)) ){ \
zIn += 3; \
}else{ \
zIn += 1; \
} \
}
#define RSKIP_UTF16LE(zIn){ \
if( *zIn>=0xD8 && (*zIn<0xE0 || (*zIn==0xE0 && *(zIn-1)==0x00)) ){ \
zIn -= 4; \
}else{ \
zIn -= 2; \
} \
}
#define RSKIP_UTF16BE(zIn){ \
zIn--; \
if( *zIn>=0xD8 && (*zIn<0xE0 || (*zIn==0xE0 && *(zIn+1)==0x00)) ){ \
zIn -= 3; \
}else{ \
zIn -= 1; \
} \
}
/*
** If the TRANSLATE_TRACE macro is defined, the value of each Mem is
** printed on stderr on the way into and out of sqlite3VdbeMemTranslate().
*/
/* #define TRANSLATE_TRACE 1 */
#ifndef SQLITE_OMIT_UTF16
/*
** This routine transforms the internal text encoding used by pMem to
** desiredEnc. It is an error if the string is already of the desired
** encoding, or if *pMem does not contain a string value.
*/
int sqlite3VdbeMemTranslate(Mem *pMem, u8 desiredEnc){
unsigned char zShort[NBFS]; /* Temporary short output buffer */
int len; /* Maximum length of output string in bytes */
unsigned char *zOut; /* Output buffer */
unsigned char *zIn; /* Input iterator */
unsigned char *zTerm; /* End of input */
unsigned char *z; /* Output iterator */
unsigned int c;
assert( pMem->flags&MEM_Str );
assert( pMem->enc!=desiredEnc );
assert( pMem->enc!=0 );
assert( pMem->n>=0 );
#if defined(TRANSLATE_TRACE) && defined(SQLITE_DEBUG)
{
char zBuf[100];
sqlite3VdbeMemPrettyPrint(pMem, zBuf);
fprintf(stderr, "INPUT: %s\n", zBuf);
}
#endif
/* If the translation is between UTF-16 little and big endian, then
** all that is required is to swap the byte order. This case is handled
** differently from the others.
*/
if( pMem->enc!=SQLITE_UTF8 && desiredEnc!=SQLITE_UTF8 ){
u8 temp;
int rc;
rc = sqlite3VdbeMemMakeWriteable(pMem);
if( rc!=SQLITE_OK ){
assert( rc==SQLITE_NOMEM );
return SQLITE_NOMEM;
}
zIn = (u8*)pMem->z;
zTerm = &zIn[pMem->n];
while( zIn<zTerm ){
temp = *zIn;
*zIn = *(zIn+1);
zIn++;
*zIn++ = temp;
}
pMem->enc = desiredEnc;
goto translate_out;
}
/* Set len to the maximum number of bytes required in the output buffer. */
if( desiredEnc==SQLITE_UTF8 ){
/* When converting from UTF-16, the maximum growth results from
** translating a 2-byte character to a 4-byte UTF-8 character.
** A single byte is required for the output string
** nul-terminator.
*/
len = pMem->n * 2 + 1;
}else{
/* When converting from UTF-8 to UTF-16 the maximum growth is caused
** when a 1-byte UTF-8 character is translated into a 2-byte UTF-16
** character. Two bytes are required in the output buffer for the
** nul-terminator.
?? 快捷鍵說明
復制代碼
Ctrl + C
搜索代碼
Ctrl + F
全屏模式
F11
切換主題
Ctrl + Shift + D
顯示快捷鍵
?
增大字號
Ctrl + =
減小字號
Ctrl + -