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