Files correlati : sqlite Ricompilazione Demo : [ ] Commento : Passaggio da Sqlite 2 a Sqlite 3.3.5 git-svn-id: svn://10.65.10.50/trunk@13902 c028cbd2-c16b-5b4b-a496-9718f37d4682
		
			
				
	
	
		
			597 lines
		
	
	
		
			20 KiB
		
	
	
	
		
			C
		
	
	
		
			Executable File
		
	
	
	
	
			
		
		
	
	
			597 lines
		
	
	
		
			20 KiB
		
	
	
	
		
			C
		
	
	
		
			Executable File
		
	
	
	
	
/*
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** 2004 April 13
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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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** This file contains routines used to translate between UTF-8, 
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** UTF-16, UTF-16BE, and UTF-16LE.
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**
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** $Id: utf.c,v 1.1 2006-04-13 12:44:29 guy Exp $
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**
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** Notes on UTF-8:
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**
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**   Byte-0    Byte-1    Byte-2    Byte-3    Value
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**  0xxxxxxx                                 00000000 00000000 0xxxxxxx
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**  110yyyyy  10xxxxxx                       00000000 00000yyy yyxxxxxx
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**  1110zzzz  10yyyyyy  10xxxxxx             00000000 zzzzyyyy yyxxxxxx
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**  11110uuu  10uuzzzz  10yyyyyy  10xxxxxx   000uuuuu zzzzyyyy yyxxxxxx
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**
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**
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** Notes on UTF-16:  (with wwww+1==uuuuu)
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**
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**      Word-0               Word-1          Value
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**  110110ww wwzzzzyy   110111yy yyxxxxxx    000uuuuu zzzzyyyy yyxxxxxx
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**  zzzzyyyy yyxxxxxx                        00000000 zzzzyyyy yyxxxxxx
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**
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**
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** BOM or Byte Order Mark:
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**     0xff 0xfe   little-endian utf-16 follows
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**     0xfe 0xff   big-endian utf-16 follows
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**
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**
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** Handling of malformed strings:
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**
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** SQLite accepts and processes malformed strings without an error wherever
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** possible. However this is not possible when converting between UTF-8 and
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** UTF-16.
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**
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** When converting malformed UTF-8 strings to UTF-16, one instance of the
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** replacement character U+FFFD for each byte that cannot be interpeted as
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** part of a valid unicode character.
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**
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** When converting malformed UTF-16 strings to UTF-8, one instance of the
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** replacement character U+FFFD for each pair of bytes that cannot be
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** interpeted as part of a valid unicode character.
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**
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** This file contains the following public routines:
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**
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** sqlite3VdbeMemTranslate() - Translate the encoding used by a Mem* string.
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** sqlite3VdbeMemHandleBom() - Handle byte-order-marks in UTF16 Mem* strings.
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** sqlite3utf16ByteLen()     - Calculate byte-length of a void* UTF16 string.
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** sqlite3utf8CharLen()      - Calculate char-length of a char* UTF8 string.
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** sqlite3utf8LikeCompare()  - Do a LIKE match given two UTF8 char* strings.
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**
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*/
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#include "sqliteInt.h"
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#include <assert.h>
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#include "vdbeInt.h"
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/*
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** This table maps from the first byte of a UTF-8 character to the number
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** of trailing bytes expected. A value '255' indicates that the table key
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** is not a legal first byte for a UTF-8 character.
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*/
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static const u8 xtra_utf8_bytes[256]  = {
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/* 0xxxxxxx */
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0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,     0, 0, 0, 0, 0, 0, 0, 0,
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/* 10wwwwww */
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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/* 110yyyyy */
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1, 1, 1, 1, 1, 1, 1, 1,     1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1,     1, 1, 1, 1, 1, 1, 1, 1,
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/* 1110zzzz */
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2, 2, 2, 2, 2, 2, 2, 2,     2, 2, 2, 2, 2, 2, 2, 2,
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/* 11110yyy */
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3, 3, 3, 3, 3, 3, 3, 3,     255, 255, 255, 255, 255, 255, 255, 255,
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};
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/*
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** This table maps from the number of trailing bytes in a UTF-8 character
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** to an integer constant that is effectively calculated for each character
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** read by a naive implementation of a UTF-8 character reader. The code
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** in the READ_UTF8 macro explains things best.
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*/
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static const int xtra_utf8_bits[4] =  {
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0,
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12416,          /* (0xC0 << 6) + (0x80) */
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925824,         /* (0xE0 << 12) + (0x80 << 6) + (0x80) */
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63447168        /* (0xF0 << 18) + (0x80 << 12) + (0x80 << 6) + 0x80 */
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};
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#define READ_UTF8(zIn, c) { \
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  int xtra;                                            \
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  c = *(zIn)++;                                        \
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  xtra = xtra_utf8_bytes[c];                           \
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  switch( xtra ){                                      \
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    case 255: c = (int)0xFFFD; break;                  \
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    case 3: c = (c<<6) + *(zIn)++;                     \
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    case 2: c = (c<<6) + *(zIn)++;                     \
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    case 1: c = (c<<6) + *(zIn)++;                     \
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    c -= xtra_utf8_bits[xtra];                         \
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  }                                                    \
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}
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int sqlite3ReadUtf8(const unsigned char *z){
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  int c;
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  READ_UTF8(z, c);
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  return c;
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}
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#define SKIP_UTF8(zIn) {                               \
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  zIn += (xtra_utf8_bytes[*(u8 *)zIn] + 1);            \
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}
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#define WRITE_UTF8(zOut, c) {                          \
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  if( c<0x00080 ){                                     \
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    *zOut++ = (c&0xFF);                                \
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  }                                                    \
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  else if( c<0x00800 ){                                \
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    *zOut++ = 0xC0 + ((c>>6)&0x1F);                    \
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    *zOut++ = 0x80 + (c & 0x3F);                       \
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  }                                                    \
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  else if( c<0x10000 ){                                \
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    *zOut++ = 0xE0 + ((c>>12)&0x0F);                   \
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    *zOut++ = 0x80 + ((c>>6) & 0x3F);                  \
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    *zOut++ = 0x80 + (c & 0x3F);                       \
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  }else{                                               \
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    *zOut++ = 0xF0 + ((c>>18) & 0x07);                 \
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    *zOut++ = 0x80 + ((c>>12) & 0x3F);                 \
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    *zOut++ = 0x80 + ((c>>6) & 0x3F);                  \
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    *zOut++ = 0x80 + (c & 0x3F);                       \
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  }                                                    \
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}
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#define WRITE_UTF16LE(zOut, c) {                                \
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  if( c<=0xFFFF ){                                              \
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    *zOut++ = (c&0x00FF);                                       \
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    *zOut++ = ((c>>8)&0x00FF);                                  \
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  }else{                                                        \
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    *zOut++ = (((c>>10)&0x003F) + (((c-0x10000)>>10)&0x00C0));  \
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    *zOut++ = (0x00D8 + (((c-0x10000)>>18)&0x03));              \
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    *zOut++ = (c&0x00FF);                                       \
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    *zOut++ = (0x00DC + ((c>>8)&0x03));                         \
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  }                                                             \
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}
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#define WRITE_UTF16BE(zOut, c) {                                \
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  if( c<=0xFFFF ){                                              \
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    *zOut++ = ((c>>8)&0x00FF);                                  \
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    *zOut++ = (c&0x00FF);                                       \
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  }else{                                                        \
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    *zOut++ = (0x00D8 + (((c-0x10000)>>18)&0x03));              \
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    *zOut++ = (((c>>10)&0x003F) + (((c-0x10000)>>10)&0x00C0));  \
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    *zOut++ = (0x00DC + ((c>>8)&0x03));                         \
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    *zOut++ = (c&0x00FF);                                       \
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  }                                                             \
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}
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#define READ_UTF16LE(zIn, c){                                         \
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  c = (*zIn++);                                                       \
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  c += ((*zIn++)<<8);                                                 \
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  if( c>=0xD800 && c<=0xE000 ){                                       \
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    int c2 = (*zIn++);                                                \
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    c2 += ((*zIn++)<<8);                                              \
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    c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);   \
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  }                                                                   \
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}
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#define READ_UTF16BE(zIn, c){                                         \
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  c = ((*zIn++)<<8);                                                  \
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  c += (*zIn++);                                                      \
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  if( c>=0xD800 && c<=0xE000 ){                                       \
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    int c2 = ((*zIn++)<<8);                                           \
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    c2 += (*zIn++);                                                   \
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    c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);   \
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  }                                                                   \
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}
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#define SKIP_UTF16BE(zIn){                                            \
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  if( *zIn>=0xD8 && (*zIn<0xE0 || (*zIn==0xE0 && *(zIn+1)==0x00)) ){  \
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    zIn += 4;                                                         \
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  }else{                                                              \
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    zIn += 2;                                                         \
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  }                                                                   \
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}
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#define SKIP_UTF16LE(zIn){                                            \
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  zIn++;                                                              \
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  if( *zIn>=0xD8 && (*zIn<0xE0 || (*zIn==0xE0 && *(zIn-1)==0x00)) ){  \
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    zIn += 3;                                                         \
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  }else{                                                              \
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    zIn += 1;                                                         \
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  }                                                                   \
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}
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#define RSKIP_UTF16LE(zIn){                                            \
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  if( *zIn>=0xD8 && (*zIn<0xE0 || (*zIn==0xE0 && *(zIn-1)==0x00)) ){  \
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    zIn -= 4;                                                         \
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  }else{                                                              \
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    zIn -= 2;                                                         \
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  }                                                                   \
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}
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#define RSKIP_UTF16BE(zIn){                                            \
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  zIn--;                                                              \
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  if( *zIn>=0xD8 && (*zIn<0xE0 || (*zIn==0xE0 && *(zIn+1)==0x00)) ){  \
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    zIn -= 3;                                                         \
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  }else{                                                              \
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    zIn -= 1;                                                         \
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  }                                                                   \
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}
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/*
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** If the TRANSLATE_TRACE macro is defined, the value of each Mem is
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** printed on stderr on the way into and out of sqlite3VdbeMemTranslate().
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*/ 
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/* #define TRANSLATE_TRACE 1 */
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#ifndef SQLITE_OMIT_UTF16
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/*
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** This routine transforms the internal text encoding used by pMem to
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** desiredEnc. It is an error if the string is already of the desired
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** encoding, or if *pMem does not contain a string value.
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*/
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int sqlite3VdbeMemTranslate(Mem *pMem, u8 desiredEnc){
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  unsigned char zShort[NBFS]; /* Temporary short output buffer */
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  int len;                    /* Maximum length of output string in bytes */
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  unsigned char *zOut;                  /* Output buffer */
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  unsigned char *zIn;                   /* Input iterator */
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  unsigned char *zTerm;                 /* End of input */
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  unsigned char *z;                     /* Output iterator */
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  int c;
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  assert( pMem->flags&MEM_Str );
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  assert( pMem->enc!=desiredEnc );
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  assert( pMem->enc!=0 );
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  assert( pMem->n>=0 );
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#if defined(TRANSLATE_TRACE) && defined(SQLITE_DEBUG)
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  {
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    char zBuf[100];
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    sqlite3VdbeMemPrettyPrint(pMem, zBuf);
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    fprintf(stderr, "INPUT:  %s\n", zBuf);
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  }
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#endif
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  /* If the translation is between UTF-16 little and big endian, then 
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  ** all that is required is to swap the byte order. This case is handled
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  ** differently from the others.
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  */
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  if( pMem->enc!=SQLITE_UTF8 && desiredEnc!=SQLITE_UTF8 ){
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    u8 temp;
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    int rc;
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    rc = sqlite3VdbeMemMakeWriteable(pMem);
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    if( rc!=SQLITE_OK ){
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      assert( rc==SQLITE_NOMEM );
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      return SQLITE_NOMEM;
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    }
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    zIn = (u8*)pMem->z;
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    zTerm = &zIn[pMem->n];
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    while( zIn<zTerm ){
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      temp = *zIn;
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      *zIn = *(zIn+1);
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      zIn++;
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      *zIn++ = temp;
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    }
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    pMem->enc = desiredEnc;
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    goto translate_out;
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  }
 | 
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 | 
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  /* Set len to the maximum number of bytes required in the output buffer. */
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  if( desiredEnc==SQLITE_UTF8 ){
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    /* When converting from UTF-16, the maximum growth results from
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    ** translating a 2-byte character to a 3-byte UTF-8 character (i.e.
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    ** code-point 0xFFFC). A single byte is required for the output string
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    ** nul-terminator.
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    */
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    len = (pMem->n/2) * 3 + 1;
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						|
  }else{
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    /* When converting from UTF-8 to UTF-16 the maximum growth is caused
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    ** when a 1-byte UTF-8 character is translated into a 2-byte UTF-16
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    ** character. Two bytes are required in the output buffer for the
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    ** nul-terminator.
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    */
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    len = pMem->n * 2 + 2;
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						|
  }
 | 
						|
 | 
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  /* Set zIn to point at the start of the input buffer and zTerm to point 1
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  ** byte past the end.
 | 
						|
  **
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  ** Variable zOut is set to point at the output buffer. This may be space
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  ** obtained from malloc(), or Mem.zShort, if it large enough and not in
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  ** use, or the zShort array on the stack (see above).
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  */
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  zIn = (u8*)pMem->z;
 | 
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  zTerm = &zIn[pMem->n];
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  if( len>NBFS ){
 | 
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    zOut = sqliteMallocRaw(len);
 | 
						|
    if( !zOut ) return SQLITE_NOMEM;
 | 
						|
  }else{
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    zOut = zShort;
 | 
						|
  }
 | 
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  z = zOut;
 | 
						|
 | 
						|
  if( pMem->enc==SQLITE_UTF8 ){
 | 
						|
    if( desiredEnc==SQLITE_UTF16LE ){
 | 
						|
      /* UTF-8 -> UTF-16 Little-endian */
 | 
						|
      while( zIn<zTerm ){
 | 
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        READ_UTF8(zIn, c); 
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        WRITE_UTF16LE(z, c);
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						|
      }
 | 
						|
    }else{
 | 
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      assert( desiredEnc==SQLITE_UTF16BE );
 | 
						|
      /* UTF-8 -> UTF-16 Big-endian */
 | 
						|
      while( zIn<zTerm ){
 | 
						|
        READ_UTF8(zIn, c); 
 | 
						|
        WRITE_UTF16BE(z, c);
 | 
						|
      }
 | 
						|
    }
 | 
						|
    pMem->n = z - zOut;
 | 
						|
    *z++ = 0;
 | 
						|
  }else{
 | 
						|
    assert( desiredEnc==SQLITE_UTF8 );
 | 
						|
    if( pMem->enc==SQLITE_UTF16LE ){
 | 
						|
      /* UTF-16 Little-endian -> UTF-8 */
 | 
						|
      while( zIn<zTerm ){
 | 
						|
        READ_UTF16LE(zIn, c); 
 | 
						|
        WRITE_UTF8(z, c);
 | 
						|
      }
 | 
						|
    }else{
 | 
						|
      /* UTF-16 Little-endian -> UTF-8 */
 | 
						|
      while( zIn<zTerm ){
 | 
						|
        READ_UTF16BE(zIn, c); 
 | 
						|
        WRITE_UTF8(z, c);
 | 
						|
      }
 | 
						|
    }
 | 
						|
    pMem->n = z - zOut;
 | 
						|
  }
 | 
						|
  *z = 0;
 | 
						|
  assert( (pMem->n+(desiredEnc==SQLITE_UTF8?1:2))<=len );
 | 
						|
 | 
						|
  sqlite3VdbeMemRelease(pMem);
 | 
						|
  pMem->flags &= ~(MEM_Static|MEM_Dyn|MEM_Ephem|MEM_Short);
 | 
						|
  pMem->enc = desiredEnc;
 | 
						|
  if( zOut==zShort ){
 | 
						|
    memcpy(pMem->zShort, zOut, len);
 | 
						|
    zOut = (u8*)pMem->zShort;
 | 
						|
    pMem->flags |= (MEM_Term|MEM_Short);
 | 
						|
  }else{
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						|
    pMem->flags |= (MEM_Term|MEM_Dyn);
 | 
						|
  }
 | 
						|
  pMem->z = (char*)zOut;
 | 
						|
 | 
						|
translate_out:
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						|
#if defined(TRANSLATE_TRACE) && defined(SQLITE_DEBUG)
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						|
  {
 | 
						|
    char zBuf[100];
 | 
						|
    sqlite3VdbeMemPrettyPrint(pMem, zBuf);
 | 
						|
    fprintf(stderr, "OUTPUT: %s\n", zBuf);
 | 
						|
  }
 | 
						|
#endif
 | 
						|
  return SQLITE_OK;
 | 
						|
}
 | 
						|
 | 
						|
/*
 | 
						|
** This routine checks for a byte-order mark at the beginning of the 
 | 
						|
** UTF-16 string stored in *pMem. If one is present, it is removed and
 | 
						|
** the encoding of the Mem adjusted. This routine does not do any
 | 
						|
** byte-swapping, it just sets Mem.enc appropriately.
 | 
						|
**
 | 
						|
** The allocation (static, dynamic etc.) and encoding of the Mem may be
 | 
						|
** changed by this function.
 | 
						|
*/
 | 
						|
int sqlite3VdbeMemHandleBom(Mem *pMem){
 | 
						|
  int rc = SQLITE_OK;
 | 
						|
  u8 bom = 0;
 | 
						|
 | 
						|
  if( pMem->n<0 || pMem->n>1 ){
 | 
						|
    u8 b1 = *(u8 *)pMem->z;
 | 
						|
    u8 b2 = *(((u8 *)pMem->z) + 1);
 | 
						|
    if( b1==0xFE && b2==0xFF ){
 | 
						|
      bom = SQLITE_UTF16BE;
 | 
						|
    }
 | 
						|
    if( b1==0xFF && b2==0xFE ){
 | 
						|
      bom = SQLITE_UTF16LE;
 | 
						|
    }
 | 
						|
  }
 | 
						|
  
 | 
						|
  if( bom ){
 | 
						|
    /* This function is called as soon as a string is stored in a Mem*,
 | 
						|
    ** from within sqlite3VdbeMemSetStr(). At that point it is not possible
 | 
						|
    ** for the string to be stored in Mem.zShort, or for it to be stored
 | 
						|
    ** in dynamic memory with no destructor.
 | 
						|
    */
 | 
						|
    assert( !(pMem->flags&MEM_Short) );
 | 
						|
    assert( !(pMem->flags&MEM_Dyn) || pMem->xDel );
 | 
						|
    if( pMem->flags & MEM_Dyn ){
 | 
						|
      void (*xDel)(void*) = pMem->xDel;
 | 
						|
      char *z = pMem->z;
 | 
						|
      pMem->z = 0;
 | 
						|
      pMem->xDel = 0;
 | 
						|
      rc = sqlite3VdbeMemSetStr(pMem, &z[2], pMem->n-2, bom, SQLITE_TRANSIENT);
 | 
						|
      xDel(z);
 | 
						|
    }else{
 | 
						|
      rc = sqlite3VdbeMemSetStr(pMem, &pMem->z[2], pMem->n-2, bom, 
 | 
						|
          SQLITE_TRANSIENT);
 | 
						|
    }
 | 
						|
  }
 | 
						|
  return rc;
 | 
						|
}
 | 
						|
#endif /* SQLITE_OMIT_UTF16 */
 | 
						|
 | 
						|
/*
 | 
						|
** pZ is a UTF-8 encoded unicode string. If nByte is less than zero,
 | 
						|
** return the number of unicode characters in pZ up to (but not including)
 | 
						|
** the first 0x00 byte. If nByte is not less than zero, return the
 | 
						|
** number of unicode characters in the first nByte of pZ (or up to 
 | 
						|
** the first 0x00, whichever comes first).
 | 
						|
*/
 | 
						|
int sqlite3utf8CharLen(const char *z, int nByte){
 | 
						|
  int r = 0;
 | 
						|
  const char *zTerm;
 | 
						|
  if( nByte>=0 ){
 | 
						|
    zTerm = &z[nByte];
 | 
						|
  }else{
 | 
						|
    zTerm = (const char *)(-1);
 | 
						|
  }
 | 
						|
  assert( z<=zTerm );
 | 
						|
  while( *z!=0 && z<zTerm ){
 | 
						|
    SKIP_UTF8(z);
 | 
						|
    r++;
 | 
						|
  }
 | 
						|
  return r;
 | 
						|
}
 | 
						|
 | 
						|
#ifndef SQLITE_OMIT_UTF16
 | 
						|
/*
 | 
						|
** Convert a UTF-16 string in the native encoding into a UTF-8 string.
 | 
						|
** Memory to hold the UTF-8 string is obtained from malloc and must be
 | 
						|
** freed by the calling function.
 | 
						|
**
 | 
						|
** NULL is returned if there is an allocation error.
 | 
						|
*/
 | 
						|
char *sqlite3utf16to8(const void *z, int nByte){
 | 
						|
  Mem m;
 | 
						|
  memset(&m, 0, sizeof(m));
 | 
						|
  sqlite3VdbeMemSetStr(&m, z, nByte, SQLITE_UTF16NATIVE, SQLITE_STATIC);
 | 
						|
  sqlite3VdbeChangeEncoding(&m, SQLITE_UTF8);
 | 
						|
  assert( m.flags & MEM_Term );
 | 
						|
  assert( m.flags & MEM_Str );
 | 
						|
  return (m.flags & MEM_Dyn)!=0 ? m.z : sqliteStrDup(m.z);
 | 
						|
}
 | 
						|
 | 
						|
/*
 | 
						|
** pZ is a UTF-16 encoded unicode string. If nChar is less than zero,
 | 
						|
** return the number of bytes up to (but not including), the first pair
 | 
						|
** of consecutive 0x00 bytes in pZ. If nChar is not less than zero,
 | 
						|
** then return the number of bytes in the first nChar unicode characters
 | 
						|
** in pZ (or up until the first pair of 0x00 bytes, whichever comes first).
 | 
						|
*/
 | 
						|
int sqlite3utf16ByteLen(const void *zIn, int nChar){
 | 
						|
  int c = 1;
 | 
						|
  char const *z = zIn;
 | 
						|
  int n = 0;
 | 
						|
  if( SQLITE_UTF16NATIVE==SQLITE_UTF16BE ){
 | 
						|
    /* Using an "if (SQLITE_UTF16NATIVE==SQLITE_UTF16BE)" construct here
 | 
						|
    ** and in other parts of this file means that at one branch will
 | 
						|
    ** not be covered by coverage testing on any single host. But coverage
 | 
						|
    ** will be complete if the tests are run on both a little-endian and 
 | 
						|
    ** big-endian host. Because both the UTF16NATIVE and SQLITE_UTF16BE
 | 
						|
    ** macros are constant at compile time the compiler can determine
 | 
						|
    ** which branch will be followed. It is therefore assumed that no runtime
 | 
						|
    ** penalty is paid for this "if" statement.
 | 
						|
    */
 | 
						|
    while( c && ((nChar<0) || n<nChar) ){
 | 
						|
      READ_UTF16BE(z, c);
 | 
						|
      n++;
 | 
						|
    }
 | 
						|
  }else{
 | 
						|
    while( c && ((nChar<0) || n<nChar) ){
 | 
						|
      READ_UTF16LE(z, c);
 | 
						|
      n++;
 | 
						|
    }
 | 
						|
  }
 | 
						|
  return (z-(char const *)zIn)-((c==0)?2:0);
 | 
						|
}
 | 
						|
 | 
						|
/*
 | 
						|
** UTF-16 implementation of the substr()
 | 
						|
*/
 | 
						|
void sqlite3utf16Substr(
 | 
						|
  sqlite3_context *context,
 | 
						|
  int argc,
 | 
						|
  sqlite3_value **argv
 | 
						|
){
 | 
						|
  int y, z;
 | 
						|
  unsigned char const *zStr;
 | 
						|
  unsigned char const *zStrEnd;
 | 
						|
  unsigned char const *zStart;
 | 
						|
  unsigned char const *zEnd;
 | 
						|
  int i;
 | 
						|
 | 
						|
  zStr = (unsigned char const *)sqlite3_value_text16(argv[0]);
 | 
						|
  zStrEnd = &zStr[sqlite3_value_bytes16(argv[0])];
 | 
						|
  y = sqlite3_value_int(argv[1]);
 | 
						|
  z = sqlite3_value_int(argv[2]);
 | 
						|
 | 
						|
  if( y>0 ){
 | 
						|
    y = y-1;
 | 
						|
    zStart = zStr;
 | 
						|
    if( SQLITE_UTF16BE==SQLITE_UTF16NATIVE ){
 | 
						|
      for(i=0; i<y && zStart<zStrEnd; i++) SKIP_UTF16BE(zStart);
 | 
						|
    }else{
 | 
						|
      for(i=0; i<y && zStart<zStrEnd; i++) SKIP_UTF16LE(zStart);
 | 
						|
    }
 | 
						|
  }else{
 | 
						|
    zStart = zStrEnd;
 | 
						|
    if( SQLITE_UTF16BE==SQLITE_UTF16NATIVE ){
 | 
						|
      for(i=y; i<0 && zStart>zStr; i++) RSKIP_UTF16BE(zStart);
 | 
						|
    }else{
 | 
						|
      for(i=y; i<0 && zStart>zStr; i++) RSKIP_UTF16LE(zStart);
 | 
						|
    }
 | 
						|
    for(; i<0; i++) z -= 1;
 | 
						|
  }
 | 
						|
 | 
						|
  zEnd = zStart;
 | 
						|
  if( SQLITE_UTF16BE==SQLITE_UTF16NATIVE ){
 | 
						|
    for(i=0; i<z && zEnd<zStrEnd; i++) SKIP_UTF16BE(zEnd);
 | 
						|
  }else{
 | 
						|
    for(i=0; i<z && zEnd<zStrEnd; i++) SKIP_UTF16LE(zEnd);
 | 
						|
  }
 | 
						|
 | 
						|
  sqlite3_result_text16(context, zStart, zEnd-zStart, SQLITE_TRANSIENT);
 | 
						|
}
 | 
						|
 | 
						|
#if defined(SQLITE_TEST)
 | 
						|
/*
 | 
						|
** This routine is called from the TCL test function "translate_selftest".
 | 
						|
** It checks that the primitives for serializing and deserializing
 | 
						|
** characters in each encoding are inverses of each other.
 | 
						|
*/
 | 
						|
void sqlite3utfSelfTest(){
 | 
						|
  int i;
 | 
						|
  unsigned char zBuf[20];
 | 
						|
  unsigned char *z;
 | 
						|
  int n;
 | 
						|
  int c;
 | 
						|
 | 
						|
  for(i=0; i<0x00110000; i++){
 | 
						|
    z = zBuf;
 | 
						|
    WRITE_UTF8(z, i);
 | 
						|
    n = z-zBuf;
 | 
						|
    z = zBuf;
 | 
						|
    READ_UTF8(z, c);
 | 
						|
    assert( c==i );
 | 
						|
    assert( (z-zBuf)==n );
 | 
						|
  }
 | 
						|
  for(i=0; i<0x00110000; i++){
 | 
						|
    if( i>=0xD800 && i<=0xE000 ) continue;
 | 
						|
    z = zBuf;
 | 
						|
    WRITE_UTF16LE(z, i);
 | 
						|
    n = z-zBuf;
 | 
						|
    z = zBuf;
 | 
						|
    READ_UTF16LE(z, c);
 | 
						|
    assert( c==i );
 | 
						|
    assert( (z-zBuf)==n );
 | 
						|
  }
 | 
						|
  for(i=0; i<0x00110000; i++){
 | 
						|
    if( i>=0xD800 && i<=0xE000 ) continue;
 | 
						|
    z = zBuf;
 | 
						|
    WRITE_UTF16BE(z, i);
 | 
						|
    n = z-zBuf;
 | 
						|
    z = zBuf;
 | 
						|
    READ_UTF16BE(z, c);
 | 
						|
    assert( c==i );
 | 
						|
    assert( (z-zBuf)==n );
 | 
						|
  }
 | 
						|
}
 | 
						|
#endif /* SQLITE_TEST */
 | 
						|
#endif /* SQLITE_OMIT_UTF16 */
 |