1 /*

     2 ** 2004 April 13

     3 **

     4 ** The author disclaims copyright to this source code.  In place of

     5 ** a legal notice, here is a blessing:

     6 **

     7 **    May you do good and not evil.

     8 **    May you find forgiveness for yourself and forgive others.

     9 **    May you share freely, never taking more than you give.

    10 **

    11 *************************************************************************

    12 ** This file contains routines used to translate between UTF-8, 

    13 ** UTF-16, UTF-16BE, and UTF-16LE.

    14 **

    15 ** $Id: utf.cpp 1282 2008-11-13 09:31:33Z LarsPson $

    16 **

    17 ** Notes on UTF-8:

    18 **

    19 **   Byte-0    Byte-1    Byte-2    Byte-3    Value

    20 **  0xxxxxxx                                 00000000 00000000 0xxxxxxx

    21 **  110yyyyy  10xxxxxx                       00000000 00000yyy yyxxxxxx

    22 **  1110zzzz  10yyyyyy  10xxxxxx             00000000 zzzzyyyy yyxxxxxx

    23 **  11110uuu  10uuzzzz  10yyyyyy  10xxxxxx   000uuuuu zzzzyyyy yyxxxxxx

    24 **

    25 **

    26 ** Notes on UTF-16:  (with wwww+1==uuuuu)

    27 **

    28 **      Word-0               Word-1          Value

    29 **  110110ww wwzzzzyy   110111yy yyxxxxxx    000uuuuu zzzzyyyy yyxxxxxx

    30 **  zzzzyyyy yyxxxxxx                        00000000 zzzzyyyy yyxxxxxx

    31 **

    32 **

    33 ** BOM or Byte Order Mark:

    34 **     0xff 0xfe   little-endian utf-16 follows

    35 **     0xfe 0xff   big-endian utf-16 follows

    36 **

    37 */

    38 #include "sqliteInt.h"

    39 #include <assert.h>

    40 #include "vdbeInt.h"

    41 

    42 /*

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

    44 ** SQLITE_LITTLEENDIAN macros.

    45 */

    46 const int sqlite3one = 1;

    47 

    48 /*

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

    50 ** a multi-byte UTF8 character.

    51 */

    52 static const unsigned char sqlite3UtfTrans1[] = {

    53   0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,

    54   0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,

    55   0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,

    56   0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,

    57   0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,

    58   0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,

    59   0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,

    60   0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,

    61 };

    62 

    63 

    64 #define WRITE_UTF8(zOut, c) {                          \

    65   if( c<0x00080 ){                                     \

    66     *zOut++ = (c&0xFF);                                \

    67   }                                                    \

    68   else if( c<0x00800 ){                                \

    69     *zOut++ = 0xC0 + ((c>>6)&0x1F);                    \

    70     *zOut++ = 0x80 + (c & 0x3F);                       \

    71   }                                                    \

    72   else if( c<0x10000 ){                                \

    73     *zOut++ = 0xE0 + ((c>>12)&0x0F);                   \

    74     *zOut++ = 0x80 + ((c>>6) & 0x3F);                  \

    75     *zOut++ = 0x80 + (c & 0x3F);                       \

    76   }else{                                               \

    77     *zOut++ = 0xF0 + ((c>>18) & 0x07);                 \

    78     *zOut++ = 0x80 + ((c>>12) & 0x3F);                 \

    79     *zOut++ = 0x80 + ((c>>6) & 0x3F);                  \

    80     *zOut++ = 0x80 + (c & 0x3F);                       \

    81   }                                                    \

    82 }

    83 

    84 #define WRITE_UTF16LE(zOut, c) {                                \

    85   if( c<=0xFFFF ){                                              \

    86     *zOut++ = (c&0x00FF);                                       \

    87     *zOut++ = ((c>>8)&0x00FF);                                  \

    88   }else{                                                        \

    89     *zOut++ = (((c>>10)&0x003F) + (((c-0x10000)>>10)&0x00C0));  \

    90     *zOut++ = (0x00D8 + (((c-0x10000)>>18)&0x03));              \

    91     *zOut++ = (c&0x00FF);                                       \

    92     *zOut++ = (0x00DC + ((c>>8)&0x03));                         \

    93   }                                                             \

    94 }

    95 

    96 #define WRITE_UTF16BE(zOut, c) {                                \

    97   if( c<=0xFFFF ){                                              \

    98     *zOut++ = ((c>>8)&0x00FF);                                  \

    99     *zOut++ = (c&0x00FF);                                       \

   100   }else{                                                        \

   101     *zOut++ = (0x00D8 + (((c-0x10000)>>18)&0x03));              \

   102     *zOut++ = (((c>>10)&0x003F) + (((c-0x10000)>>10)&0x00C0));  \

   103     *zOut++ = (0x00DC + ((c>>8)&0x03));                         \

   104     *zOut++ = (c&0x00FF);                                       \

   105   }                                                             \

   106 }

   107 

   108 #define READ_UTF16LE(zIn, c){                                         \

   109   c = (*zIn++);                                                       \

   110   c += ((*zIn++)<<8);                                                 \

   111   if( c>=0xD800 && c<0xE000 ){                                       \

   112     int c2 = (*zIn++);                                                \

   113     c2 += ((*zIn++)<<8);                                              \

   114     c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);   \

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

   116   }                                                                   \

   117 }

   118 

   119 #define READ_UTF16BE(zIn, c){                                         \

   120   c = ((*zIn++)<<8);                                                  \

   121   c += (*zIn++);                                                      \

   122   if( c>=0xD800 && c<0xE000 ){                                       \

   123     int c2 = ((*zIn++)<<8);                                           \

   124     c2 += (*zIn++);                                                   \

   125     c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);   \

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

   127   }                                                                   \

   128 }

   129 

   130 /*

   131 ** Translate a single UTF-8 character.  Return the unicode value.

   132 **

   133 ** During translation, assume that the byte that zTerm points

   134 ** is a 0x00.

   135 **

   136 ** Write a pointer to the next unread byte back into *pzNext.

   137 **

   138 ** Notes On Invalid UTF-8:

   139 **

   140 **  *  This routine never allows a 7-bit character (0x00 through 0x7f) to

   141 **     be encoded as a multi-byte character.  Any multi-byte character that

   142 **     attempts to encode a value between 0x00 and 0x7f is rendered as 0xfffd.

   143 **

   144 **  *  This routine never allows a UTF16 surrogate value to be encoded.

   145 **     If a multi-byte character attempts to encode a value between

   146 **     0xd800 and 0xe000 then it is rendered as 0xfffd.

   147 **

   148 **  *  Bytes in the range of 0x80 through 0xbf which occur as the first

   149 **     byte of a character are interpreted as single-byte characters

   150 **     and rendered as themselves even though they are technically

   151 **     invalid characters.

   152 **

   153 **  *  This routine accepts an infinite number of different UTF8 encodings

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

   155 **     encodings to 0xfffd as some systems recommend.

   156 */

   157 int sqlite3Utf8Read(

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

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

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

   161 ){

   162   int c = *(z++);

   163   if( c>=0xc0 ){

   164     c = sqlite3UtfTrans1[c-0xc0];

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

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

   167     }

   168     if( c<0x80

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

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

   171   }

   172   *pzNext = z;

   173   return c;

   174 }

   175 

   176 

   177 

   178 /*

   179 ** If the TRANSLATE_TRACE macro is defined, the value of each Mem is

   180 ** printed on stderr on the way into and out of sqlite3VdbeMemTranslate().

   181 */ 

   182 /* #define TRANSLATE_TRACE 1 */

   183 

   184 #ifndef SQLITE_OMIT_UTF16

   185 /*

   186 ** This routine transforms the internal text encoding used by pMem to

   187 ** desiredEnc. It is an error if the string is already of the desired

   188 ** encoding, or if *pMem does not contain a string value.

   189 */

   190 int sqlite3VdbeMemTranslate(Mem *pMem, u8 desiredEnc){

   191   unsigned char zShort[NBFS]; /* Temporary short output buffer */

   192   int len;                    /* Maximum length of output string in bytes */

   193   unsigned char *zOut;                  /* Output buffer */

   194   unsigned char *zIn;                   /* Input iterator */

   195   unsigned char *zTerm;                 /* End of input */

   196   unsigned char *z;                     /* Output iterator */

   197   unsigned int c;

   198 

   199   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );

   200   assert( pMem->flags&MEM_Str );

   201   assert( pMem->enc!=desiredEnc );

   202   assert( pMem->enc!=0 );

   203   assert( pMem->n>=0 );

   204 

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

   206   {

   207     char zBuf[100];

   208     sqlite3VdbeMemPrettyPrint(pMem, zBuf);

   209     fprintf(stderr, "INPUT:  %s\n", zBuf);

   210   }

   211 #endif

   212 

   213   /* If the translation is between UTF-16 little and big endian, then 

   214   ** all that is required is to swap the byte order. This case is handled

   215   ** differently from the others.

   216   */

   217   if( pMem->enc!=SQLITE_UTF8 && desiredEnc!=SQLITE_UTF8 ){

   218     u8 temp;

   219     int rc;

   220     rc = sqlite3VdbeMemMakeWriteable(pMem);

   221     if( rc!=SQLITE_OK ){

   222       assert( rc==SQLITE_NOMEM );

   223       return SQLITE_NOMEM;

   224     }

   225     zIn = (u8*)pMem->z;

   226     zTerm = &zIn[pMem->n];

   227     while( zIn<zTerm ){

   228       temp = *zIn;

   229       *zIn = *(zIn+1);

   230       zIn++;

   231       *zIn++ = temp;

   232     }

   233     pMem->enc = desiredEnc;

   234     goto translate_out;

   235   }

   236 

   237   /* Set len to the maximum number of bytes required in the output buffer. */

   238   if( desiredEnc==SQLITE_UTF8 ){

   239     /* When converting from UTF-16, the maximum growth results from

   240     ** translating a 2-byte character to a 4-byte UTF-8 character.

   241     ** A single byte is required for the output string

   242     ** nul-terminator.

   243     */

   244     len = pMem->n * 2 + 1;

   245   }else{

   246     /* When converting from UTF-8 to UTF-16 the maximum growth is caused

   247     ** when a 1-byte UTF-8 character is translated into a 2-byte UTF-16

   248     ** character. Two bytes are required in the output buffer for the

   249     ** nul-terminator.

   250     */

   251     len = pMem->n * 2 + 2;

   252   }

   253 

   254   /* Set zIn to point at the start of the input buffer and zTerm to point 1

   255   ** byte past the end.

   256   **

   257   ** Variable zOut is set to point at the output buffer. This may be space

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

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

   260   */

   261   zIn = (u8*)pMem->z;

   262   zTerm = &zIn[pMem->n];

   263   if( len>NBFS ){

   264     zOut = (unsigned char*)sqlite3DbMallocRaw(pMem->db, len);

   265     if( !zOut ){

   266       return SQLITE_NOMEM;

   267     }

   268   }else{

   269     zOut = zShort;

   270   }

   271   z = zOut;

   272 

   273   if( pMem->enc==SQLITE_UTF8 ){

   274     if( desiredEnc==SQLITE_UTF16LE ){

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

   276       while( zIn<zTerm ){

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

   278         WRITE_UTF16LE(z, c);

   279       }

   280     }else{

   281       assert( desiredEnc==SQLITE_UTF16BE );

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

   283       while( zIn<zTerm ){

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

   285         WRITE_UTF16BE(z, c);

   286       }

   287     }

   288     pMem->n = z - zOut;

   289     *z++ = 0;

   290   }else{

   291     assert( desiredEnc==SQLITE_UTF8 );

   292     if( pMem->enc==SQLITE_UTF16LE ){

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

   294       while( zIn<zTerm ){

   295         READ_UTF16LE(zIn, c); 

   296         WRITE_UTF8(z, c);

   297       }

   298     }else{

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

   300       while( zIn<zTerm ){

   301         READ_UTF16BE(zIn, c); 

   302         WRITE_UTF8(z, c);

   303       }

   304     }

   305     pMem->n = z - zOut;

   306   }

   307   *z = 0;

   308   assert( (pMem->n+(desiredEnc==SQLITE_UTF8?1:2))<=len );

   309 

   310   sqlite3VdbeMemRelease(pMem);

   311   pMem->flags &= ~(MEM_Static|MEM_Dyn|MEM_Ephem|MEM_Short);

   312   pMem->enc = desiredEnc;

   313   if( zOut==zShort ){

   314     memcpy(pMem->zShort, zOut, len);

   315     zOut = (u8*)pMem->zShort;

   316     pMem->flags |= (MEM_Term|MEM_Short);

   317   }else{

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

   319   }

   320   pMem->z = (char*)zOut;

   321 

   322 translate_out:

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

   324   {

   325     char zBuf[100];

   326     sqlite3VdbeMemPrettyPrint(pMem, zBuf);

   327     fprintf(stderr, "OUTPUT: %s\n", zBuf);

   328   }

   329 #endif

   330   return SQLITE_OK;

   331 }

   332 

   333 /*

   334 ** This routine checks for a byte-order mark at the beginning of the 

   335 ** UTF-16 string stored in *pMem. If one is present, it is removed and

   336 ** the encoding of the Mem adjusted. This routine does not do any

   337 ** byte-swapping, it just sets Mem.enc appropriately.

   338 **

   339 ** The allocation (static, dynamic etc.) and encoding of the Mem may be

   340 ** changed by this function.

   341 */

   342 int sqlite3VdbeMemHandleBom(Mem *pMem){

   343   int rc = SQLITE_OK;

   344   u8 bom = 0;

   345 

   346   if( pMem->n<0 || pMem->n>1 ){

   347     u8 b1 = *(u8 *)pMem->z;

   348     u8 b2 = *(((u8 *)pMem->z) + 1);

   349     if( b1==0xFE && b2==0xFF ){

   350       bom = SQLITE_UTF16BE;

   351     }

   352     if( b1==0xFF && b2==0xFE ){

   353       bom = SQLITE_UTF16LE;

   354     }

   355   }

   356   

   357   if( bom ){

   358     /* This function is called as soon as a string is stored in a Mem*,

   359     ** from within sqlite3VdbeMemSetStr(). At that point it is not possible

   360     ** for the string to be stored in Mem.zShort, or for it to be stored

   361     ** in dynamic memory with no destructor.

   362     */

   363     assert( !(pMem->flags&MEM_Short) );

   364     assert( !(pMem->flags&MEM_Dyn) || pMem->xDel );

   365     if( pMem->flags & MEM_Dyn ){

   366       void (*xDel)(void*) = pMem->xDel;

   367       char *z = pMem->z;

   368       pMem->z = 0;

   369       pMem->xDel = 0;

   370       rc = sqlite3VdbeMemSetStr(pMem, &z[2], pMem->n-2, bom, 

   371           SQLITE_TRANSIENT);

   372       xDel(z);

   373     }else{

   374       rc = sqlite3VdbeMemSetStr(pMem, &pMem->z[2], pMem->n-2, bom, 

   375           SQLITE_TRANSIENT);

   376     }

   377   }

   378   return rc;

   379 }

   380 #endif /* SQLITE_OMIT_UTF16 */

   381 

   382 /*

   383 ** pZ is a UTF-8 encoded unicode string. If nByte is less than zero,

   384 ** return the number of unicode characters in pZ up to (but not including)

   385 ** the first 0x00 byte. If nByte is not less than zero, return the

   386 ** number of unicode characters in the first nByte of pZ (or up to 

   387 ** the first 0x00, whichever comes first).

   388 */

   389 int sqlite3Utf8CharLen(const char *zIn, int nByte){

   390   int r = 0;

   391   const u8 *z = (const u8*)zIn;

   392   const u8 *zTerm;

   393   if( nByte>=0 ){

   394     zTerm = &z[nByte];

   395   }else{

   396     zTerm = (const u8*)(-1);

   397   }

   398   assert( z<=zTerm );

   399   while( *z!=0 && z<zTerm ){

   400     SQLITE_SKIP_UTF8(z);

   401     r++;

   402   }

   403   return r;

   404 }

   405 

   406 /* This test function is not currently used by the automated test-suite. 

   407 ** Hence it is only available in debug builds.

   408 */

   409 #if defined(SQLITE_TEST) && defined(SQLITE_DEBUG)

   410 /*

   411 ** Translate UTF-8 to UTF-8.

   412 **

   413 ** This has the effect of making sure that the string is well-formed

   414 ** UTF-8.  Miscoded characters are removed.

   415 **

   416 ** The translation is done in-place (since it is impossible for the

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

   418 */

   419 int sqlite3Utf8To8(unsigned char *zIn){

   420   unsigned char *zOut = zIn;

   421   unsigned char *zStart = zIn;

   422   unsigned char *zTerm;

   423   u32 c;

   424 

   425   while( zIn[0] ){

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

   427     if( c!=0xfffd ){

   428       WRITE_UTF8(zOut, c);

   429     }

   430   }

   431   *zOut = 0;

   432   return zOut - zStart;

   433 }

   434 #endif

   435 

   436 #ifndef SQLITE_OMIT_UTF16

   437 /*

   438 ** Convert a UTF-16 string in the native encoding into a UTF-8 string.

   439 ** Memory to hold the UTF-8 string is obtained from sqlite3_malloc and must

   440 ** be freed by the calling function.

   441 **

   442 ** NULL is returned if there is an allocation error.

   443 */

   444 char *sqlite3Utf16to8(sqlite3 *db, const void *z, int nByte){

   445   Mem m;

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

   447   m.db = db;

   448   sqlite3VdbeMemSetStr(&m, (const char*)z, nByte, SQLITE_UTF16NATIVE, SQLITE_STATIC);

   449   sqlite3VdbeChangeEncoding(&m, SQLITE_UTF8);

   450   if( db->mallocFailed ){

   451     sqlite3VdbeMemRelease(&m);

   452     m.z = 0;

   453   }

   454   assert( (m.flags & MEM_Term)!=0 || db->mallocFailed );

   455   assert( (m.flags & MEM_Str)!=0 || db->mallocFailed );

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

   457 }

   458 

   459 /*

   460 ** pZ is a UTF-16 encoded unicode string. If nChar is less than zero,

   461 ** return the number of bytes up to (but not including), the first pair

   462 ** of consecutive 0x00 bytes in pZ. If nChar is not less than zero,

   463 ** then return the number of bytes in the first nChar unicode characters

   464 ** in pZ (or up until the first pair of 0x00 bytes, whichever comes first).

   465 */

   466 int sqlite3Utf16ByteLen(const void *zIn, int nChar){

   467   unsigned int c = 1;

   468   char const *z = (const char*)zIn;

   469   int n = 0;

   470   if( SQLITE_UTF16NATIVE==SQLITE_UTF16BE ){

   471     /* Using an "if (SQLITE_UTF16NATIVE==SQLITE_UTF16BE)" construct here

   472     ** and in other parts of this file means that at one branch will

   473     ** not be covered by coverage testing on any single host. But coverage

   474     ** will be complete if the tests are run on both a little-endian and 

   475     ** big-endian host. Because both the UTF16NATIVE and SQLITE_UTF16BE

   476     ** macros are constant at compile time the compiler can determine

   477     ** which branch will be followed. It is therefore assumed that no runtime

   478     ** penalty is paid for this "if" statement.

   479     */

   480     while( c && ((nChar<0) || n<nChar) ){

   481       READ_UTF16BE(z, c);

   482       n++;

   483     }

   484   }else{

   485     while( c && ((nChar<0) || n<nChar) ){

   486       READ_UTF16LE(z, c);

   487       n++;

   488     }

   489   }

   490   return (z-(char const *)zIn)-((c==0)?2:0);

   491 }

   492 

   493 #if defined(SQLITE_TEST)

   494 /*

   495 ** This routine is called from the TCL test function "translate_selftest".

   496 ** It checks that the primitives for serializing and deserializing

   497 ** characters in each encoding are inverses of each other.

   498 */

   499 void sqlite3UtfSelfTest(){

   500   unsigned int i, t;

   501   unsigned char zBuf[20];

   502   unsigned char *z;

   503   unsigned char *zTerm;

   504   int n;

   505   unsigned int c;

   506 

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

   508     z = zBuf;

   509     WRITE_UTF8(z, i);

   510     n = z-zBuf;

   511     z[0] = 0;

   512     zTerm = z;

   513     z = zBuf;

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

   515     t = i;

   516     if( i>=0xD800 && i<=0xDFFF ) t = 0xFFFD;

   517     if( (i&0xFFFFFFFE)==0xFFFE ) t = 0xFFFD;

   518     assert( c==t );

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

   520   }

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

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

   523     z = zBuf;

   524     WRITE_UTF16LE(z, i);

   525     n = z-zBuf;

   526     z[0] = 0;

   527     z = zBuf;

   528     READ_UTF16LE(z, c);

   529     assert( c==i );

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

   531   }

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

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

   534     z = zBuf;

   535     WRITE_UTF16BE(z, i);

   536     n = z-zBuf;

   537     z[0] = 0;

   538     z = zBuf;

   539     READ_UTF16BE(z, c);

   540     assert( c==i );

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

   542   }

   543 }

   544 #endif /* SQLITE_TEST */

   545 #endif /* SQLITE_OMIT_UTF16 */