iconv/loop.c

   1 /* Conversion loop frame work.
   2    Copyright (C) 1998-2002, 2003 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 /* This file provides a frame for the reader loop in all conversion modules.
  22    The actual code must (of course) be provided in the actual module source
  23    code but certain actions can be written down generically, with some
  24    customization options which are these:
  25
  26      MIN_NEEDED_INPUT   minimal number of input bytes needed for the next
  27                         conversion.
  28      MIN_NEEDED_OUTPUT  minimal number of bytes produced by the next round
  29                         of conversion.
  30
  31      MAX_NEEDED_INPUT   you guess it, this is the maximal number of input
  32                         bytes needed.  It defaults to MIN_NEEDED_INPUT
  33      MAX_NEEDED_OUTPUT  likewise for output bytes.
  34
  35      LOOPFCT            name of the function created.  If not specified
  36                         the name is `loop' but this prevents the use
  37                         of multiple functions in the same file.
  38
  39      BODY               this is supposed to expand to the body of the loop.
  40                         The user must provide this.
  41
  42      EXTRA_LOOP_DECLS   extra arguments passed from converion loop call.
  43
  44      INIT_PARAMS        code to define and initialize variables from params.
  45      UPDATE_PARAMS      code to store result in params.
  46
  47      ONEBYTE_BODY       body of the specialized conversion function for a
  48                         single byte from the current character set to INTERNAL.
  49 */
  50
  51 #include <assert.h>
  52 #include <endian.h>
  53 #include <gconv.h>
  54 #include <stdint.h>
  55 #include <string.h>
  56 #include <wchar.h>
  57 #include <sys/param.h>          /* For MIN.  */
  58 #define __need_size_t
  59 #include <stddef.h>
  60
  61
  62 /* We have to provide support for machines which are not able to handled
  63    unaligned memory accesses.  Some of the character encodings have
  64    representations with a fixed width of 2 or 4 bytes.  But if we cannot
  65    access unaligned memory we still have to read byte-wise.  */
  66 #undef FCTNAME2
  67 #if defined _STRING_ARCH_unaligned || !defined DEFINE_UNALIGNED
  68 /* We can handle unaligned memory access.  */
  69 # define get16(addr) *((__const uint16_t *) (addr))
  70 # define get32(addr) *((__const uint32_t *) (addr))
  71
  72 /* We need no special support for writing values either.  */
  73 # define put16(addr, val) *((uint16_t *) (addr)) = (val)
  74 # define put32(addr, val) *((uint32_t *) (addr)) = (val)
  75
  76 # define FCTNAME2(name) name
  77 #else
  78 /* Distinguish between big endian and little endian.  */
  79 # if __BYTE_ORDER == __LITTLE_ENDIAN
  80 #  define get16(addr) \
  81      (((__const unsigned char *) (addr))[1] << 8                              \
  82       | ((__const unsigned char *) (addr))[0])
  83 #  define get32(addr) \
  84      (((((__const unsigned char *) (addr))[3] << 8                            \
  85         | ((__const unsigned char *) (addr))[2]) << 8                         \
  86        | ((__const unsigned char *) (addr))[1]) << 8                          \
  87       | ((__const unsigned char *) (addr))[0])
  88
  89 #  define put16(addr, val) \
  90      ({ uint16_t __val = (val);                                               \
  91         ((unsigned char *) (addr))[0] = __val;                                \
  92         ((unsigned char *) (addr))[1] = __val >> 8;                           \
  93         (void) 0; })
  94 #  define put32(addr, val) \
  95      ({ uint32_t __val = (val);                                               \
  96         ((unsigned char *) (addr))[0] = __val;                                \
  97         __val >>= 8;                                                          \
  98         ((unsigned char *) (addr))[1] = __val;                                \
  99         __val >>= 8;                                                          \
 100         ((unsigned char *) (addr))[2] = __val;                                \
 101         __val >>= 8;                                                          \
 102         ((unsigned char *) (addr))[3] = __val;                                \
 103         (void) 0; })
 104 # else
 105 #  define get16(addr) \
 106      (((__const unsigned char *) (addr))[0] << 8                              \
 107       | ((__const unsigned char *) (addr))[1])
 108 #  define get32(addr) \
 109      (((((__const unsigned char *) (addr))[0] << 8                            \
 110         | ((__const unsigned char *) (addr))[1]) << 8                         \
 111        | ((__const unsigned char *) (addr))[2]) << 8                          \
 112       | ((__const unsigned char *) (addr))[3])
 113
 114 #  define put16(addr, val) \
 115      ({ uint16_t __val = (val);                                               \
 116         ((unsigned char *) (addr))[1] = __val;                                \
 117         ((unsigned char *) (addr))[0] = __val >> 8;                           \
 118         (void) 0; })
 119 #  define put32(addr, val) \
 120      ({ uint32_t __val = (val);                                               \
 121         ((unsigned char *) (addr))[3] = __val;                                \
 122         __val >>= 8;                                                          \
 123         ((unsigned char *) (addr))[2] = __val;                                \
 124         __val >>= 8;                                                          \
 125         ((unsigned char *) (addr))[1] = __val;                                \
 126         __val >>= 8;                                                          \
 127         ((unsigned char *) (addr))[0] = __val;                                \
 128         (void) 0; })
 129 # endif
 130
 131 # define FCTNAME2(name) name##_unaligned
 132 #endif
 133 #define FCTNAME(name) FCTNAME2(name)
 134
 135
 136 /* We need at least one byte for the next round.  */
 137 #ifndef MIN_NEEDED_INPUT
 138 # error "MIN_NEEDED_INPUT definition missing"
 139 #elif MIN_NEEDED_INPUT < 1
 140 # error "MIN_NEEDED_INPUT must be >= 1"
 141 #endif
 142
 143 /* Let's see how many bytes we produce.  */
 144 #ifndef MAX_NEEDED_INPUT
 145 # define MAX_NEEDED_INPUT       MIN_NEEDED_INPUT
 146 #endif
 147
 148 /* We produce at least one byte in the next round.  */
 149 #ifndef MIN_NEEDED_OUTPUT
 150 # error "MIN_NEEDED_OUTPUT definition missing"
 151 #elif MIN_NEEDED_OUTPUT < 1
 152 # error "MIN_NEEDED_OUTPUT must be >= 1"
 153 #endif
 154
 155 /* Let's see how many bytes we produce.  */
 156 #ifndef MAX_NEEDED_OUTPUT
 157 # define MAX_NEEDED_OUTPUT      MIN_NEEDED_OUTPUT
 158 #endif
 159
 160 /* Default name for the function.  */
 161 #ifndef LOOPFCT
 162 # define LOOPFCT                loop
 163 #endif
 164
 165 /* Make sure we have a loop body.  */
 166 #ifndef BODY
 167 # error "Definition of BODY missing for function" LOOPFCT
 168 #endif
 169
 170
 171 /* If no arguments have to passed to the loop function define the macro
 172    as empty.  */
 173 #ifndef EXTRA_LOOP_DECLS
 174 # define EXTRA_LOOP_DECLS
 175 #endif
 176
 177
 178 /* To make it easier for the writers of the modules, we define a macro
 179    to test whether we have to ignore errors.  */
 180 #define ignore_errors_p() \
 181   (irreversible != NULL && (flags & __GCONV_IGNORE_ERRORS))
 182
 183
 184 /* Error handling for the FROM_LOOP direction, with ignoring of errors.
 185    Note that we cannot use the do while (0) trick since `break' and
 186    `continue' must reach certain points.  */
 187 #define STANDARD_FROM_LOOP_ERR_HANDLER(Incr) \
 188   {                                                                           \
 189     result = __GCONV_ILLEGAL_INPUT;                                           \
 190                                                                               \
 191     if (! ignore_errors_p ())                                                 \
 192       break;                                                                  \
 193                                                                               \
 194     /* We ignore the invalid input byte sequence.  */                         \
 195     inptr += (Incr);                                                          \
 196     ++*irreversible;                                                          \
 197     /* But we keep result == __GCONV_ILLEGAL_INPUT, because of the constraint \
 198        that "iconv -c" must give the same exitcode as "iconv".  */            \
 199     continue;                                                                 \
 200   }
 201
 202 /* Error handling for the TO_LOOP direction, with use of transliteration/
 203    transcription functions and ignoring of errors.  Note that we cannot use
 204    the do while (0) trick since `break' and `continue' must reach certain
 205    points.  */
 206 #define STANDARD_TO_LOOP_ERR_HANDLER(Incr) \
 207   {                                                                           \
 208     struct __gconv_trans_data *trans;                                         \
 209                                                                               \
 210     result = __GCONV_ILLEGAL_INPUT;                                           \
 211                                                                               \
 212     if (irreversible == NULL)                                                 \
 213       /* This means we are in call from __gconv_transliterate.  In this       \
 214          case we are not doing any error recovery outself.  */                \
 215       break;                                                                  \
 216                                                                               \
 217     /* First try the transliteration methods.  */                             \
 218     for (trans = step_data->__trans; trans != NULL; trans = trans->__next)    \
 219       {                                                                       \
 220         result = DL_CALL_FCT (trans->__trans_fct,                             \
 221                               (step, step_data, trans->__data, *inptrp,       \
 222                                &inptr, inend, &outptr, irreversible));        \
 223         if (result != __GCONV_ILLEGAL_INPUT)                                  \
 224           break;                                                              \
 225       }                                                                       \
 226     /* If any of them recognized the input continue with the loop.  */        \
 227     if (result != __GCONV_ILLEGAL_INPUT)                                      \
 228       continue;                                                               \
 229                                                                               \
 230     /* Next see whether we have to ignore the error.  If not, stop.  */       \
 231     if (! ignore_errors_p ())                                                 \
 232       break;                                                                  \
 233                                                                               \
 234     /* When we come here it means we ignore the character.  */                \
 235     ++*irreversible;                                                          \
 236     inptr += Incr;                                                            \
 237     /* But we keep result == __GCONV_ILLEGAL_INPUT, because of the constraint \
 238        that "iconv -c" must give the same exitcode as "iconv".  */            \
 239     continue;                                                                 \
 240   }
 241
 242
 243 /* Handling of Unicode 3.1 TAG characters.  Unicode recommends
 244    "If language codes are not relevant to the particular processing
 245     operation, then they should be ignored."  This macro is usually
 246    called right before  STANDARD_TO_LOOP_ERR_HANDLER (Incr).  */
 247 #define UNICODE_TAG_HANDLER(Character, Incr) \
 248   {                                                                           \
 249     /* TAG characters are those in the range U+E0000..U+E007F.  */            \
 250     if (((Character) >> 7) == (0xe0000 >> 7))                                 \
 251       {                                                                       \
 252         inptr += Incr;                                                        \
 253         continue;                                                             \
 254       }                                                                       \
 255   }
 256
 257
 258 /* The function returns the status, as defined in gconv.h.  */
 259 static inline int
 260 FCTNAME (LOOPFCT) (struct __gconv_step *step,
 261                    struct __gconv_step_data *step_data,
 262                    const unsigned char **inptrp, const unsigned char *inend,
 263                    unsigned char **outptrp, const unsigned char *outend,
 264                    size_t *irreversible EXTRA_LOOP_DECLS)
 265 {
 266 #ifdef LOOP_NEED_STATE
 267   mbstate_t *state = step_data->__statep;
 268 #endif
 269 #ifdef LOOP_NEED_FLAGS
 270   int flags = step_data->__flags;
 271 #endif
 272 #ifdef LOOP_NEED_DATA
 273   void *data = step->__data;
 274 #endif
 275   int result = __GCONV_EMPTY_INPUT;
 276   const unsigned char *inptr = *inptrp;
 277   unsigned char *outptr = *outptrp;
 278
 279 #ifdef INIT_PARAMS
 280   INIT_PARAMS;
 281 #endif
 282
 283   while (inptr != inend)
 284     {
 285       /* `if' cases for MIN_NEEDED_OUTPUT ==/!= 1 is made to help the
 286          compiler generating better code.  They will be optimized away
 287          since MIN_NEEDED_OUTPUT is always a constant.  */
 288       if (MIN_NEEDED_INPUT > 1
 289           && __builtin_expect (inptr + MIN_NEEDED_INPUT > inend, 0))
 290         {
 291           /* We don't have enough input for another complete input
 292              character.  */
 293           result = __GCONV_INCOMPLETE_INPUT;
 294           break;
 295         }
 296       if ((MIN_NEEDED_OUTPUT != 1
 297            && __builtin_expect (outptr + MIN_NEEDED_OUTPUT > outend, 0))
 298           || (MIN_NEEDED_OUTPUT == 1
 299               && __builtin_expect (outptr >= outend, 0)))
 300         {
 301           /* Overflow in the output buffer.  */
 302           result = __GCONV_FULL_OUTPUT;
 303           break;
 304         }
 305
 306       /* Here comes the body the user provides.  It can stop with
 307          RESULT set to GCONV_INCOMPLETE_INPUT (if the size of the
 308          input characters vary in size), GCONV_ILLEGAL_INPUT, or
 309          GCONV_FULL_OUTPUT (if the output characters vary in size).  */
 310       BODY
 311     }
 312
 313   /* Update the pointers pointed to by the parameters.  */
 314   *inptrp = inptr;
 315   *outptrp = outptr;
 316 #ifdef UPDATE_PARAMS
 317   UPDATE_PARAMS;
 318 #endif
 319
 320   return result;
 321 }
 322
 323
 324 /* Include the file a second time to define the function to handle
 325    unaligned access.  */
 326 #if !defined DEFINE_UNALIGNED && !defined _STRING_ARCH_unaligned \
 327     && MIN_NEEDED_INPUT != 1 && MAX_NEEDED_INPUT % MIN_NEEDED_INPUT == 0 \
 328     && MIN_NEEDED_OUTPUT != 1 && MAX_NEEDED_OUTPUT % MIN_NEEDED_OUTPUT == 0
 329 # undef get16
 330 # undef get32
 331 # undef put16
 332 # undef put32
 333 # undef unaligned
 334
 335 # define DEFINE_UNALIGNED
 336 # include "loop.c"
 337 # undef DEFINE_UNALIGNED
 338 #endif
 339
 340
 341 #if MAX_NEEDED_INPUT > 1
 342 # define SINGLE(fct) SINGLE2 (fct)
 343 # define SINGLE2(fct) fct##_single
 344 static inline int
 345 SINGLE(LOOPFCT) (struct __gconv_step *step,
 346                  struct __gconv_step_data *step_data,
 347                  const unsigned char **inptrp, const unsigned char *inend,
 348                  unsigned char **outptrp, unsigned char *outend,
 349                  size_t *irreversible EXTRA_LOOP_DECLS)
 350 {
 351   mbstate_t *state = step_data->__statep;
 352 #ifdef LOOP_NEED_FLAGS
 353   int flags = step_data->__flags;
 354 #endif
 355 #ifdef LOOP_NEED_DATA
 356   void *data = step->__data;
 357 #endif
 358   int result = __GCONV_OK;
 359   unsigned char bytebuf[MAX_NEEDED_INPUT];
 360   const unsigned char *inptr = *inptrp;
 361   unsigned char *outptr = *outptrp;
 362   size_t inlen;
 363
 364 #ifdef INIT_PARAMS
 365   INIT_PARAMS;
 366 #endif
 367
 368 #ifdef UNPACK_BYTES
 369   UNPACK_BYTES
 370 #else
 371   /* Add the bytes from the state to the input buffer.  */
 372   for (inlen = 0; inlen < (size_t) (state->__count & 7); ++inlen)
 373     bytebuf[inlen] = state->__value.__wchb[inlen];
 374 #endif
 375
 376   /* Are there enough bytes in the input buffer?  */
 377   if (__builtin_expect (inptr + (MIN_NEEDED_INPUT - inlen) > inend, 0))
 378     {
 379       *inptrp = inend;
 380 #ifdef STORE_REST
 381       inptr = bytebuf;
 382       inptrp = &inptr;
 383       inend = &bytebuf[inlen];
 384
 385       STORE_REST
 386 #else
 387       /* We don't have enough input for another complete input
 388          character.  */
 389       while (inptr < inend)
 390         state->__value.__wchb[inlen++] = *inptr++;
 391 #endif
 392
 393       return __GCONV_INCOMPLETE_INPUT;
 394     }
 395
 396   /* Enough space in output buffer.  */
 397   if ((MIN_NEEDED_OUTPUT != 1 && outptr + MIN_NEEDED_OUTPUT > outend)
 398       || (MIN_NEEDED_OUTPUT == 1 && outptr >= outend))
 399     /* Overflow in the output buffer.  */
 400     return __GCONV_FULL_OUTPUT;
 401
 402   /*  Now add characters from the normal input buffer.  */
 403   do
 404     bytebuf[inlen++] = *inptr++;
 405   while (inlen < MAX_NEEDED_INPUT && inptr < inend);
 406
 407   inptr = bytebuf;
 408   inend = &bytebuf[inlen];
 409
 410   do
 411     {
 412       BODY
 413     }
 414   while (0);
 415
 416   /* Now we either have produced an output character and consumed all the
 417      bytes from the state and at least one more, or the character is still
 418      incomplete, or we have some other error (like illegal input character,
 419      no space in output buffer).  */
 420   if (__builtin_expect (inptr != bytebuf, 1))
 421     {
 422       /* We found a new character.  */
 423       assert (inptr - bytebuf > (state->__count & 7));
 424
 425       *inptrp += inptr - bytebuf - (state->__count & 7);
 426       *outptrp = outptr;
 427
 428       result = __GCONV_OK;
 429
 430       /* Clear the state buffer.  */
 431 #ifdef CLEAR_STATE
 432       CLEAR_STATE;
 433 #else
 434       state->__count &= ~7;
 435 #endif
 436     }
 437   else if (result == __GCONV_INCOMPLETE_INPUT)
 438     {
 439       /* This can only happen if we have less than MAX_NEEDED_INPUT bytes
 440          available.  */
 441       assert (inend != &bytebuf[MAX_NEEDED_INPUT]);
 442
 443       *inptrp += inend - bytebuf - (state->__count & 7);
 444 #ifdef STORE_REST
 445       inptrp = &inptr;
 446
 447       STORE_REST
 448 #else
 449       /* We don't have enough input for another complete input
 450          character.  */
 451       while (inptr < inend)
 452         state->__value.__wchb[inlen++] = *inptr++;
 453 #endif
 454     }
 455
 456   return result;
 457 }
 458 # undef SINGLE
 459 # undef SINGLE2
 460 #endif
 461
 462
 463 #ifdef ONEBYTE_BODY
 464 /* Define the shortcut function for btowc.  */
 465 static wint_t
 466 gconv_btowc (struct __gconv_step *step, unsigned char c)
 467   ONEBYTE_BODY
 468 # define FROM_ONEBYTE gconv_btowc
 469 #endif
 470
 471
 472 /* We remove the macro definitions so that we can include this file again
 473    for the definition of another function.  */
 474 #undef MIN_NEEDED_INPUT
 475 #undef MAX_NEEDED_INPUT
 476 #undef MIN_NEEDED_OUTPUT
 477 #undef MAX_NEEDED_OUTPUT
 478 #undef LOOPFCT
 479 #undef BODY
 480 #undef LOOPFCT
 481 #undef EXTRA_LOOP_DECLS
 482 #undef INIT_PARAMS
 483 #undef UPDATE_PARAMS
 484 #undef ONEBYTE_BODY
 485 #undef UNPACK_BYTES
 486 #undef CLEAR_STATE
 487 #undef LOOP_NEED_STATE
 488 #undef LOOP_NEED_FLAGS
 489 #undef LOOP_NEED_DATA
 490 #undef get16
 491 #undef get32
 492 #undef put16
 493 #undef put32
 494 #undef unaligned