iconv/loop.c

   1 /* Conversion loop frame work.
   2    Copyright (C) 1998-2002, 2003, 2005 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       {                                                                       \
 229         if (__builtin_expect (result == __GCONV_FULL_OUTPUT, 0))              \
 230           break;                                                              \
 231                                                                               \
 232         continue;                                                             \
 233       }                                                                       \
 234                                                                               \
 235     /* Next see whether we have to ignore the error.  If not, stop.  */       \
 236     if (! ignore_errors_p ())                                                 \
 237       break;                                                                  \
 238                                                                               \
 239     /* When we come here it means we ignore the character.  */                \
 240     ++*irreversible;                                                          \
 241     inptr += Incr;                                                            \
 242     /* But we keep result == __GCONV_ILLEGAL_INPUT, because of the constraint \
 243        that "iconv -c" must give the same exitcode as "iconv".  */            \
 244     continue;                                                                 \
 245   }
 246
 247
 248 /* Handling of Unicode 3.1 TAG characters.  Unicode recommends
 249    "If language codes are not relevant to the particular processing
 250     operation, then they should be ignored."  This macro is usually
 251    called right before  STANDARD_TO_LOOP_ERR_HANDLER (Incr).  */
 252 #define UNICODE_TAG_HANDLER(Character, Incr) \
 253   {                                                                           \
 254     /* TAG characters are those in the range U+E0000..U+E007F.  */            \
 255     if (((Character) >> 7) == (0xe0000 >> 7))                                 \
 256       {                                                                       \
 257         inptr += Incr;                                                        \
 258         continue;                                                             \
 259       }                                                                       \
 260   }
 261
 262
 263 /* The function returns the status, as defined in gconv.h.  */
 264 static inline int
 265 __attribute ((always_inline))
 266 FCTNAME (LOOPFCT) (struct __gconv_step *step,
 267                    struct __gconv_step_data *step_data,
 268                    const unsigned char **inptrp, const unsigned char *inend,
 269                    unsigned char **outptrp, const unsigned char *outend,
 270                    size_t *irreversible EXTRA_LOOP_DECLS)
 271 {
 272 #ifdef LOOP_NEED_STATE
 273   mbstate_t *state = step_data->__statep;
 274 #endif
 275 #ifdef LOOP_NEED_FLAGS
 276   int flags = step_data->__flags;
 277 #endif
 278 #ifdef LOOP_NEED_DATA
 279   void *data = step->__data;
 280 #endif
 281   int result = __GCONV_EMPTY_INPUT;
 282   const unsigned char *inptr = *inptrp;
 283   unsigned char *outptr = *outptrp;
 284
 285 #ifdef INIT_PARAMS
 286   INIT_PARAMS;
 287 #endif
 288
 289   while (inptr != inend)
 290     {
 291       /* `if' cases for MIN_NEEDED_OUTPUT ==/!= 1 is made to help the
 292          compiler generating better code.  They will be optimized away
 293          since MIN_NEEDED_OUTPUT is always a constant.  */
 294       if (MIN_NEEDED_INPUT > 1
 295           && __builtin_expect (inptr + MIN_NEEDED_INPUT > inend, 0))
 296         {
 297           /* We don't have enough input for another complete input
 298              character.  */
 299           result = __GCONV_INCOMPLETE_INPUT;
 300           break;
 301         }
 302       if ((MIN_NEEDED_OUTPUT != 1
 303            && __builtin_expect (outptr + MIN_NEEDED_OUTPUT > outend, 0))
 304           || (MIN_NEEDED_OUTPUT == 1
 305               && __builtin_expect (outptr >= outend, 0)))
 306         {
 307           /* Overflow in the output buffer.  */
 308           result = __GCONV_FULL_OUTPUT;
 309           break;
 310         }
 311
 312       /* Here comes the body the user provides.  It can stop with
 313          RESULT set to GCONV_INCOMPLETE_INPUT (if the size of the
 314          input characters vary in size), GCONV_ILLEGAL_INPUT, or
 315          GCONV_FULL_OUTPUT (if the output characters vary in size).  */
 316       BODY
 317     }
 318
 319   /* Update the pointers pointed to by the parameters.  */
 320   *inptrp = inptr;
 321   *outptrp = outptr;
 322 #ifdef UPDATE_PARAMS
 323   UPDATE_PARAMS;
 324 #endif
 325
 326   return result;
 327 }
 328
 329
 330 /* Include the file a second time to define the function to handle
 331    unaligned access.  */
 332 #if !defined DEFINE_UNALIGNED && !defined _STRING_ARCH_unaligned \
 333     && MIN_NEEDED_INPUT != 1 && MAX_NEEDED_INPUT % MIN_NEEDED_INPUT == 0 \
 334     && MIN_NEEDED_OUTPUT != 1 && MAX_NEEDED_OUTPUT % MIN_NEEDED_OUTPUT == 0
 335 # undef get16
 336 # undef get32
 337 # undef put16
 338 # undef put32
 339 # undef unaligned
 340
 341 # define DEFINE_UNALIGNED
 342 # include "loop.c"
 343 # undef DEFINE_UNALIGNED
 344 #endif
 345
 346
 347 #if MAX_NEEDED_INPUT > 1
 348 # define SINGLE(fct) SINGLE2 (fct)
 349 # define SINGLE2(fct) fct##_single
 350 static inline int
 351 __attribute ((always_inline))
 352 SINGLE(LOOPFCT) (struct __gconv_step *step,
 353                  struct __gconv_step_data *step_data,
 354                  const unsigned char **inptrp, const unsigned char *inend,
 355                  unsigned char **outptrp, unsigned char *outend,
 356                  size_t *irreversible EXTRA_LOOP_DECLS)
 357 {
 358   mbstate_t *state = step_data->__statep;
 359 #ifdef LOOP_NEED_FLAGS
 360   int flags = step_data->__flags;
 361 #endif
 362 #ifdef LOOP_NEED_DATA
 363   void *data = step->__data;
 364 #endif
 365   int result = __GCONV_OK;
 366   unsigned char bytebuf[MAX_NEEDED_INPUT];
 367   const unsigned char *inptr = *inptrp;
 368   unsigned char *outptr = *outptrp;
 369   size_t inlen;
 370
 371 #ifdef INIT_PARAMS
 372   INIT_PARAMS;
 373 #endif
 374
 375 #ifdef UNPACK_BYTES
 376   UNPACK_BYTES
 377 #else
 378   /* Add the bytes from the state to the input buffer.  */
 379   for (inlen = 0; inlen < (size_t) (state->__count & 7); ++inlen)
 380     bytebuf[inlen] = state->__value.__wchb[inlen];
 381 #endif
 382
 383   /* Are there enough bytes in the input buffer?  */
 384   if (__builtin_expect (inptr + (MIN_NEEDED_INPUT - inlen) > inend, 0))
 385     {
 386       *inptrp = inend;
 387 #ifdef STORE_REST
 388       inptr = bytebuf;
 389       inptrp = &inptr;
 390       inend = &bytebuf[inlen];
 391
 392       STORE_REST
 393 #else
 394       /* We don't have enough input for another complete input
 395          character.  */
 396       while (inptr < inend)
 397         state->__value.__wchb[inlen++] = *inptr++;
 398 #endif
 399
 400       return __GCONV_INCOMPLETE_INPUT;
 401     }
 402
 403   /* Enough space in output buffer.  */
 404   if ((MIN_NEEDED_OUTPUT != 1 && outptr + MIN_NEEDED_OUTPUT > outend)
 405       || (MIN_NEEDED_OUTPUT == 1 && outptr >= outend))
 406     /* Overflow in the output buffer.  */
 407     return __GCONV_FULL_OUTPUT;
 408
 409   /*  Now add characters from the normal input buffer.  */
 410   do
 411     bytebuf[inlen++] = *inptr++;
 412   while (inlen < MAX_NEEDED_INPUT && inptr < inend);
 413
 414   inptr = bytebuf;
 415   inend = &bytebuf[inlen];
 416
 417   do
 418     {
 419       BODY
 420     }
 421   while (0);
 422
 423   /* Now we either have produced an output character and consumed all the
 424      bytes from the state and at least one more, or the character is still
 425      incomplete, or we have some other error (like illegal input character,
 426      no space in output buffer).  */
 427   if (__builtin_expect (inptr != bytebuf, 1))
 428     {
 429       /* We found a new character.  */
 430       assert (inptr - bytebuf > (state->__count & 7));
 431
 432       *inptrp += inptr - bytebuf - (state->__count & 7);
 433       *outptrp = outptr;
 434
 435       result = __GCONV_OK;
 436
 437       /* Clear the state buffer.  */
 438 #ifdef CLEAR_STATE
 439       CLEAR_STATE;
 440 #else
 441       state->__count &= ~7;
 442 #endif
 443     }
 444   else if (result == __GCONV_INCOMPLETE_INPUT)
 445     {
 446       /* This can only happen if we have less than MAX_NEEDED_INPUT bytes
 447          available.  */
 448       assert (inend != &bytebuf[MAX_NEEDED_INPUT]);
 449
 450       *inptrp += inend - bytebuf - (state->__count & 7);
 451 #ifdef STORE_REST
 452       inptrp = &inptr;
 453
 454       STORE_REST
 455 #else
 456       /* We don't have enough input for another complete input
 457          character.  */
 458       assert (inend - inptr > (state->__count & ~7));
 459       assert (inend - inptr <= 7);
 460       state->__count = (state->__count & ~7) | (inend - inptr);
 461       inlen = 0;
 462       while (inptr < inend)
 463         state->__value.__wchb[inlen++] = *inptr++;
 464 #endif
 465     }
 466
 467   return result;
 468 }
 469 # undef SINGLE
 470 # undef SINGLE2
 471 #endif
 472
 473
 474 #ifdef ONEBYTE_BODY
 475 /* Define the shortcut function for btowc.  */
 476 static wint_t
 477 gconv_btowc (struct __gconv_step *step, unsigned char c)
 478   ONEBYTE_BODY
 479 # define FROM_ONEBYTE gconv_btowc
 480 #endif
 481
 482
 483 /* We remove the macro definitions so that we can include this file again
 484    for the definition of another function.  */
 485 #undef MIN_NEEDED_INPUT
 486 #undef MAX_NEEDED_INPUT
 487 #undef MIN_NEEDED_OUTPUT
 488 #undef MAX_NEEDED_OUTPUT
 489 #undef LOOPFCT
 490 #undef BODY
 491 #undef LOOPFCT
 492 #undef EXTRA_LOOP_DECLS
 493 #undef INIT_PARAMS
 494 #undef UPDATE_PARAMS
 495 #undef ONEBYTE_BODY
 496 #undef UNPACK_BYTES
 497 #undef CLEAR_STATE
 498 #undef LOOP_NEED_STATE
 499 #undef LOOP_NEED_FLAGS
 500 #undef LOOP_NEED_DATA
 501 #undef get16
 502 #undef get32
 503 #undef put16
 504 #undef put32
 505 #undef unaligned