/*

 ** 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.

 **

 ** $Id$

 **

 ** 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"

 /*

 ** The following constant value is used by the SQLITE_BIGENDIAN and

 ** SQLITE_LITTLEENDIAN macros.

 */

 const int sqlite3one = 1;

 /*

 ** This lookup table is used to help decode the first byte of

 ** a multi-byte UTF8 character.

 */

 static const unsigned char sqlite3UtfTrans1[] = {

   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++ = (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);   \

     if( (c & 0xFFFF0000)==0 ) c = 0xFFFD;                             \

   }                                                                   \

 }

 #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);   \

     if( (c & 0xFFFF0000)==0 ) c = 0xFFFD;                             \

   }                                                                   \

 }

 /*

 ** 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 an infinite number of different UTF8 encodings

 **     for unicode values 0x80 and greater.  It do not change over-length

 **     encodings to 0xfffd as some systems recommend.

 */

 int sqlite3Utf8Read(

   const unsigned char *z,         /* First byte of UTF-8 character */

   const unsigned char *zTerm,     /* Pretend this byte is 0x00 */

   const unsigned char **pzNext    /* Write first byte past UTF-8 char here */

 ){

   int c = *(z++);

   if( c>=0xc0 ){

     c = sqlite3UtfTrans1[c-0xc0];

     while( z!=zTerm && (*z & 0xc0)==0x80 ){

       c = (c<<6) + (0x3f & *(z++));

     }

     if( c<0x80

         || (c&0xFFFFF800)==0xD800

         || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }

   }

   *pzNext = z;

   return c;

 }

 /*

 ** 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->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)

   {

     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.

     */

     len = pMem->n * 2 + 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. This may be space

   ** obtained from sqlite3_malloc(), or Mem.zShort, if it large enough and

   ** not in use, or the zShort array on the stack (see above).

   */

   zIn = (u8*)pMem->z;

   zTerm = &zIn[pMem->n];

   if( len>NBFS ){

     zOut = sqlite3DbMallocRaw(pMem->db, len);

     if( !zOut ){

       return SQLITE_NOMEM;

     }

   }else{

     zOut = zShort;

   }

   z = zOut;

   if( pMem->enc==SQLITE_UTF8 ){

     if( desiredEnc==SQLITE_UTF16LE ){

       /* UTF-8 -> UTF-16 Little-endian */

       while( zIn<zTerm ){

         c = sqlite3Utf8Read(zIn, zTerm, (const u8**)&zIn);

         WRITE_UTF16LE(z, c);

       }

     }else{

       assert( desiredEnc==SQLITE_UTF16BE );

       /* UTF-8 -> UTF-16 Big-endian */

       while( zIn<zTerm ){

         c = sqlite3Utf8Read(zIn, zTerm, (const u8**)&zIn);

         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{

     pMem->flags |= (MEM_Term|MEM_Dyn);

   }

   pMem->z = (char*)zOut;

 translate_out:

 #if defined(TRANSLATE_TRACE) && defined(SQLITE_DEBUG)

   {

     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 *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 (since it is impossible for the

 ** correct UTF-8 encoding to be longer than a malformed encoding).

 */

 int sqlite3Utf8To8(unsigned char *zIn){

   unsigned char *zOut = zIn;

   unsigned char *zStart = zIn;

   unsigned char *zTerm;

   u32 c;

   while( zIn[0] ){

     c = sqlite3Utf8Read(zIn, zTerm, (const u8**)&zIn);

     if( c!=0xfffd ){

       WRITE_UTF8(zOut, c);

     }

   }

   *zOut = 0;

   return 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){

   Mem m;

   memset(&m, 0, sizeof(m));

   m.db = db;

   sqlite3VdbeMemSetStr(&m, z, nByte, SQLITE_UTF16NATIVE, 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 );

   return (m.flags & MEM_Dyn)!=0 ? m.z : sqlite3DbStrDup(db, 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){

   unsigned 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);

 }

 #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(){

   unsigned int i, t;

   unsigned char zBuf[20];

   unsigned char *z;

   unsigned char *zTerm;

   int n;

   unsigned int c;

   for(i=0; i<0x00110000; i++){

     z = zBuf;

     WRITE_UTF8(z, i);

     n = z-zBuf;

     z[0] = 0;

     zTerm = z;

     z = zBuf;

     c = sqlite3Utf8Read(z, zTerm, (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 );

   }

   for(i=0; i<0x00110000; i++){

     if( i>=0xD800 && i<0xE000 ) continue;

     z = zBuf;

     WRITE_UTF16LE(z, i);

     n = z-zBuf;

     z[0] = 0;

     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[0] = 0;

     z = zBuf;

     READ_UTF16BE(z, c);

     assert( c==i );

     assert( (z-zBuf)==n );

   }

 }

 #endif /* SQLITE_TEST */

 #endif /* SQLITE_OMIT_UTF16 */