/*
** 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.
**
** 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
**
*/
#include "sqliteInt.h"
#include <assert.h>
#include "vdbeInt.h"

#if !defined(SQLITE_AMALGAMATION) && SQLITE_BYTEORDER==0
/*
** The following constant value is used by the SQLITE_BIGENDIAN and
** SQLITE_LITTLEENDIAN macros.
*/
const int sqlite3one = 1;
#endif /* SQLITE_AMALGAMATION && SQLITE_BYTEORDER==0 */

/*
** This lookup table is used to help decode the first byte of
** a multi-byte UTF8 character.
*/
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 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); \
 } \
}

#define WRITE_UTF16LE(zOut, c) { \
 if( c<=0xFFFF ){ \
 *zOut++ = (u8)(c&0x00FF); \
 *zOut++ = (u8)((c>>8)&0x00FF); \
 }else{ \
 *zOut++ = (u8)(((c>>10)&0x003F) + (((c-0x10000)>>10)&0x00C0)); \
 *zOut++ = (u8)(0x00D8 + (((c-0x10000)>>18)&0x03)); \
 *zOut++ = (u8)(c&0x00FF); \
 *zOut++ = (u8)(0x00DC + ((c>>8)&0x03)); \
 } \
}

#define WRITE_UTF16BE(zOut, c) { \
 if( c<=0xFFFF ){ \
 *zOut++ = (u8)((c>>8)&0x00FF); \
 *zOut++ = (u8)(c&0x00FF); \
 }else{ \
 *zOut++ = (u8)(0x00D8 + (((c-0x10000)>>18)&0x03)); \
 *zOut++ = (u8)(((c>>10)&0x003F) + (((c-0x10000)>>10)&0x00C0)); \
 *zOut++ = (u8)(0x00DC + ((c>>8)&0x03)); \
 *zOut++ = (u8)(c&0x00FF); \
 } \
}

/*
** Translate a single UTF-8 character. Return the unicode value.
**
** During translation, assume that the byte that zTerm points
** is a 0x00.
**
** Write a pointer to the next unread byte back into *pzNext.
**
** Notes On Invalid UTF-8:
**
** * This routine never allows a 7-bit character (0x00 through 0x7f) to
** be encoded as a multi-byte character. Any multi-byte character that
** attempts to encode a value between 0x00 and 0x7f is rendered as 0xfffd.
**
** * This routine never allows a UTF16 surrogate value to be encoded.
** If a multi-byte character attempts to encode a value between
** 0xd800 and 0xe000 then it is rendered as 0xfffd.
**
** * Bytes in the range of 0x80 through 0xbf which occur as the first
** byte of a character are interpreted as single-byte characters
** and rendered as themselves even though they are technically
** invalid characters.
**
** * This routine accepts over-length UTF8 encodings
** for unicode values 0x80 and greater. It does not change over-length
** encodings to 0xfffd as some systems recommend.
*/
#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; } \
 }
u32 sqlite3Utf8Read(
 const unsigned char **pz /* Pointer to string from which to read char */
){
 unsigned int c;

 /* Same as READ_UTF8() above but without the zTerm parameter.
 ** For this routine, we assume the UTF8 string is always zero-terminated.
 */
 c = *((*pz)++);
 if( c>=0xc0 ){
 c = sqlite3Utf8Trans1[c-0xc0];
 while( (*(*pz) & 0xc0)==0x80 ){
 c = (c<<6) + (0x3f & *((*pz)++));
 }
 if( c<0x80
 || (c&0xFFFFF800)==0xD800
 || (c&0xFFFFFFFE)==0xFFFE ){ c = 0xFFFD; }
 }
 return c;
}

/*
** Read a single UTF8 character out of buffer z[], but reading no
** more than n characters from the buffer. z[] is not zero-terminated.
**
** Return the number of bytes used to construct the character.
**
** Invalid UTF8 might generate a strange result. No effort is made
** to detect invalid UTF8.
**
** At most 4 bytes will be read out of z[]. The return value will always
** be between 1 and 4.
*/
int sqlite3Utf8ReadLimited(
 const u8 *z,
 int n,
 u32 *piOut
){
 u32 c;
 int i = 1;
 assert( n>0 );
 c = z[0];
 if( c>=0xc0 ){
 c = sqlite3Utf8Trans1[c-0xc0];
 if( n>4 ) n = 4;
 while( i<n && (z[i] & 0xc0)==0x80 ){
 c = (c<<6) + (0x3f & z[i]);
 i++;
 }
 }
 *piOut = c;
 return i;
}


/*
** 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.
*/
SQLITE_NOINLINE int sqlite3VdbeMemTranslate(Mem *pMem, u8 desiredEnc){
 sqlite3_int64 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->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
 assert( pMem->flags&MEM_Str );
 assert( pMem->enc!=desiredEnc );
 assert( pMem->enc!=0 );
 assert( pMem->n>=0 );

#if defined(TRANSLATE_TRACE) && defined(SQLITE_DEBUG)
 {
 StrAccum acc;
 char zBuf[1000];
 sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0); 
 sqlite3VdbeMemPrettyPrint(pMem, &acc);
 fprintf(stderr, "INPUT: %s\n", sqlite3StrAccumFinish(&acc));
 }
#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_BKPT;
 }
 zIn = (u8*)pMem->z;
 zTerm = &zIn[pMem->n&~1];
 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.
 */
 pMem->n &= ~1;
 len = 2 * (sqlite3_int64)pMem->n + 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.
 */
 len = 2 * (sqlite3_int64)pMem->n + 2;
 }

 /* Set zIn to point at the start of the input buffer and zTerm to point 1
 ** byte past the end.
 **
 ** Variable zOut is set to point at the output buffer, space obtained
 ** from sqlite3_malloc().
 */
 zIn = (u8*)pMem->z;
 zTerm = &zIn[pMem->n];
 zOut = sqlite3DbMallocRaw(pMem->db, len);
 if( !zOut ){
 return SQLITE_NOMEM_BKPT;
 }
 z = zOut;

 if( pMem->enc==SQLITE_UTF8 ){
 if( desiredEnc==SQLITE_UTF16LE ){
 /* UTF-8 -> UTF-16 Little-endian */
 while( zIn<zTerm ){
 READ_UTF8(zIn, zTerm, c);
 WRITE_UTF16LE(z, c);
 }
 }else{
 assert( desiredEnc==SQLITE_UTF16BE );
 /* UTF-8 -> UTF-16 Big-endian */
 while( zIn<zTerm ){
 READ_UTF8(zIn, zTerm, c);
 WRITE_UTF16BE(z, c);
 }
 }
 pMem->n = (int)(z - zOut);
 *z++ = 0;
 }else{
 assert( desiredEnc==SQLITE_UTF8 );
 if( pMem->enc==SQLITE_UTF16LE ){
 /* UTF-16 Little-endian -> UTF-8 */
 while( zIn<zTerm ){
 c = *(zIn++);
 c += (*(zIn++))<<8;
 if( c>=0xd800 && c<0xe000 ){
#ifdef SQLITE_REPLACE_INVALID_UTF
 if( c>=0xdc00 || zIn>=zTerm ){
 c = 0xfffd;
 }else{
 int c2 = *(zIn++);
 c2 += (*(zIn++))<<8;
 if( c2<0xdc00 || c2>=0xe000 ){
 zIn -= 2;
 c = 0xfffd;
 }else{
 c = ((c&0x3ff)<<10) + (c2&0x3ff) + 0x10000;
 }
 }
#else
 if( zIn<zTerm ){
 int c2 = (*zIn++);
 c2 += ((*zIn++)<<8);
 c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);
 }
#endif
 }
 WRITE_UTF8(z, c);
 }
 }else{
 /* UTF-16 Big-endian -> UTF-8 */
 while( zIn<zTerm ){
 c = (*(zIn++))<<8;
 c += *(zIn++);
 if( c>=0xd800 && c<0xe000 ){
#ifdef SQLITE_REPLACE_INVALID_UTF
 if( c>=0xdc00 || zIn>=zTerm ){
 c = 0xfffd;
 }else{
 int c2 = (*(zIn++))<<8;
 c2 += *(zIn++);
 if( c2<0xdc00 || c2>=0xe000 ){
 zIn -= 2;
 c = 0xfffd;
 }else{
 c = ((c&0x3ff)<<10) + (c2&0x3ff) + 0x10000;
 }
 }
#else
 if( zIn<zTerm ){
 int c2 = ((*zIn++)<<8);
 c2 += (*zIn++);
 c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);
 }
#endif
 }
 WRITE_UTF8(z, c);
 }
 }
 pMem->n = (int)(z - zOut);
 }
 *z = 0;
 assert( (pMem->n+(desiredEnc==SQLITE_UTF8?1:2))<=len );

 c = MEM_Str|MEM_Term|(pMem->flags&(MEM_AffMask|MEM_Subtype));
 sqlite3VdbeMemRelease(pMem);
 pMem->flags = c;
 pMem->enc = desiredEnc;
 pMem->z = (char*)zOut;
 pMem->zMalloc = pMem->z;
 pMem->szMalloc = sqlite3DbMallocSize(pMem->db, pMem->z);

translate_out:
#if defined(TRANSLATE_TRACE) && defined(SQLITE_DEBUG)
 {
 StrAccum acc;
 char zBuf[1000];
 sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0); 
 sqlite3VdbeMemPrettyPrint(pMem, &acc);
 fprintf(stderr, "OUTPUT: %s\n", sqlite3StrAccumFinish(&acc));
 }
#endif
 return SQLITE_OK;
}
#endif /* SQLITE_OMIT_UTF16 */

#ifndef SQLITE_OMIT_UTF16
/*
** 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;

 assert( pMem->n>=0 );
 if( 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 ){
 rc = sqlite3VdbeMemMakeWriteable(pMem);
 if( rc==SQLITE_OK ){
 pMem->n -= 2;
 memmove(pMem->z, &pMem->z[2], pMem->n);
 pMem->z[pMem->n] = '0円';
 pMem->z[pMem->n+1] = '0円';
 pMem->flags |= MEM_Term;
 pMem->enc = bom;
 }
 }
 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 *zIn, int nByte){
 int r = 0;
 const u8 *z = (const u8*)zIn;
 const u8 *zTerm;
 if( nByte>=0 ){
 zTerm = &z[nByte];
 }else{
 zTerm = (const u8*)(-1);
 }
 assert( z<=zTerm );
 while( *z!=0 && z<zTerm ){
 SQLITE_SKIP_UTF8(z);
 r++;
 }
 return r;
}

/* This test function is not currently used by the automated test-suite. 
** Hence it is only available in debug builds.
*/
#if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)
/*
** Translate UTF-8 to UTF-8.
**
** This has the effect of making sure that the string is well-formed
** UTF-8. Miscoded characters are removed.
**
** The translation is done in-place and aborted if the output
** overruns the input.
*/
int sqlite3Utf8To8(unsigned char *zIn){
 unsigned char *zOut = zIn;
 unsigned char *zStart = zIn;
 u32 c;

 while( zIn[0] && zOut<=zIn ){
 c = sqlite3Utf8Read((const u8**)&zIn);
 if( c!=0xfffd ){
 WRITE_UTF8(zOut, c);
 }
 }
 *zOut = 0;
 return (int)(zOut - zStart);
}
#endif

#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 sqlite3_malloc and must
** be freed by the calling function.
**
** NULL is returned if there is an allocation error.
*/
char *sqlite3Utf16to8(sqlite3 *db, const void *z, int nByte, u8 enc){
 Mem m;
 memset(&m, 0, sizeof(m));
 m.db = db;
 sqlite3VdbeMemSetStr(&m, z, nByte, enc, SQLITE_STATIC);
 sqlite3VdbeChangeEncoding(&m, SQLITE_UTF8);
 if( db->mallocFailed ){
 sqlite3VdbeMemRelease(&m);
 m.z = 0;
 }
 assert( (m.flags & MEM_Term)!=0 || db->mallocFailed );
 assert( (m.flags & MEM_Str)!=0 || db->mallocFailed );
 assert( m.z || db->mallocFailed );
 return m.z;
}

/*
** zIn is a UTF-16 encoded unicode string at least nChar characters long.
** Return the number of bytes in the first nChar unicode characters
** in pZ. nChar must be non-negative.
*/
int sqlite3Utf16ByteLen(const void *zIn, int nChar){
 int c;
 unsigned char const *z = zIn;
 int n = 0;
 
 if( SQLITE_UTF16NATIVE==SQLITE_UTF16LE ) z++;
 while( n<nChar ){
 c = z[0];
 z += 2;
 if( c>=0xd8 && c<0xdc && z[0]>=0xdc && z[0]<0xe0 ) z += 2;
 n++;
 }
 return (int)(z-(unsigned char const *)zIn) 
 - (SQLITE_UTF16NATIVE==SQLITE_UTF16LE);
}

#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(void){
 unsigned int i, t;
 unsigned char zBuf[20];
 unsigned char *z;
 int n;
 unsigned int c;

 for(i=0; i<0x00110000; i++){
 z = zBuf;
 WRITE_UTF8(z, i);
 n = (int)(z-zBuf);
 assert( n>0 && n<=4 );
 z[0] = 0;
 z = zBuf;
 c = sqlite3Utf8Read((const u8**)&z);
 t = i;
 if( i>=0xD800 && i<=0xDFFF ) t = 0xFFFD;
 if( (i&0xFFFFFFFE)==0xFFFE ) t = 0xFFFD;
 assert( c==t );
 assert( (z-zBuf)==n );
 }
}
#endif /* SQLITE_TEST */
#endif /* SQLITE_OMIT_UTF16 */