iconv/loop.c

   1 /* Conversion loop frame work.
   2    Copyright (C) 1998-2017 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, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 /* This file provides a frame for the reader loop in all conversion modules.
  21    The actual code must (of course) be provided in the actual module source
  22    code but certain actions can be written down generically, with some
  23    customization options which are these:
  24
  25      MIN_NEEDED_INPUT   minimal number of input bytes needed for the next
  26                         conversion.
  27      MIN_NEEDED_OUTPUT  minimal number of bytes produced by the next round
  28                         of conversion.
  29
  30      MAX_NEEDED_INPUT   you guess it, this is the maximal number of input
  31                         bytes needed.  It defaults to MIN_NEEDED_INPUT
  32      MAX_NEEDED_OUTPUT  likewise for output bytes.
  33
  34      LOOPFCT            name of the function created.  If not specified
  35                         the name is `loop' but this prevents the use
  36                         of multiple functions in the same file.
  37
  38      BODY               this is supposed to expand to the body of the loop.
  39                         The user must provide this.
  40
  41      EXTRA_LOOP_DECLS   extra arguments passed from conversion loop call.
  42
  43      INIT_PARAMS        code to define and initialize variables from params.
  44      UPDATE_PARAMS      code to store result in params.
  45
  46      ONEBYTE_BODY       body of the specialized conversion function for a
  47                         single byte from the current character set to INTERNAL.
  48 */
  49
  50 #include <assert.h>
  51 #include <endian.h>
  52 #include <gconv.h>
  53 #include <stdint.h>
  54 #include <string.h>
  55 #include <wchar.h>
  56 #include <sys/param.h>          /* For MIN.  */
  57 #define __need_size_t
  58 #include <stddef.h>
  59 #include <libc-diag.h>
  60
  61 /* We have to provide support for machines which are not able to handled
  62    unaligned memory accesses.  Some of the character encodings have
  63    representations with a fixed width of 2 or 4 bytes.  But if we cannot
  64    access unaligned memory we still have to read byte-wise.  */
  65 #undef FCTNAME2
  66 #if _STRING_ARCH_unaligned || !defined DEFINE_UNALIGNED
  67 /* We can handle unaligned memory access.  */
  68 # define get16(addr) *((const uint16_t *) (addr))
  69 # define get32(addr) *((const uint32_t *) (addr))
  70
  71 /* We need no special support for writing values either.  */
  72 # define put16(addr, val) *((uint16_t *) (addr)) = (val)
  73 # define put32(addr, val) *((uint32_t *) (addr)) = (val)
  74
  75 # define FCTNAME2(name) name
  76 #else
  77 /* Distinguish between big endian and little endian.  */
  78 # if __BYTE_ORDER == __LITTLE_ENDIAN
  79 #  define get16(addr) \
  80      (((const unsigned char *) (addr))[1] << 8                                \
  81       | ((const unsigned char *) (addr))[0])
  82 #  define get32(addr) \
  83      (((((const unsigned char *) (addr))[3] << 8                              \
  84         | ((const unsigned char *) (addr))[2]) << 8                           \
  85        | ((const unsigned char *) (addr))[1]) << 8                            \
  86       | ((const unsigned char *) (addr))[0])
  87
  88 #  define put16(addr, val) \
  89      ({ uint16_t __val = (val);                                               \
  90         ((unsigned char *) (addr))[0] = __val;                                \
  91         ((unsigned char *) (addr))[1] = __val >> 8;                           \
  92         (void) 0; })
  93 #  define put32(addr, val) \
  94      ({ uint32_t __val = (val);                                               \
  95         ((unsigned char *) (addr))[0] = __val;                                \
  96         __val >>= 8;                                                          \
  97         ((unsigned char *) (addr))[1] = __val;                                \
  98         __val >>= 8;                                                          \
  99         ((unsigned char *) (addr))[2] = __val;                                \
 100         __val >>= 8;                                                          \
 101         ((unsigned char *) (addr))[3] = __val;                                \
 102         (void) 0; })
 103 # else
 104 #  define get16(addr) \
 105      (((const unsigned char *) (addr))[0] << 8                                \
 106       | ((const unsigned char *) (addr))[1])
 107 #  define get32(addr) \
 108      (((((const unsigned char *) (addr))[0] << 8                              \
 109         | ((const unsigned char *) (addr))[1]) << 8                           \
 110        | ((const unsigned char *) (addr))[2]) << 8                            \
 111       | ((const unsigned char *) (addr))[3])
 112
 113 #  define put16(addr, val) \
 114      ({ uint16_t __val = (val);                                               \
 115         ((unsigned char *) (addr))[1] = __val;                                \
 116         ((unsigned char *) (addr))[0] = __val >> 8;                           \
 117         (void) 0; })
 118 #  define put32(addr, val) \
 119      ({ uint32_t __val = (val);                                               \
 120         ((unsigned char *) (addr))[3] = __val;                                \
 121         __val >>= 8;                                                          \
 122         ((unsigned char *) (addr))[2] = __val;                                \
 123         __val >>= 8;                                                          \
 124         ((unsigned char *) (addr))[1] = __val;                                \
 125         __val >>= 8;                                                          \
 126         ((unsigned char *) (addr))[0] = __val;                                \
 127         (void) 0; })
 128 # endif
 129
 130 # define FCTNAME2(name) name##_unaligned
 131 #endif
 132 #define FCTNAME(name) FCTNAME2(name)
 133
 134
 135 /* We need at least one byte for the next round.  */
 136 #ifndef MIN_NEEDED_INPUT
 137 # error "MIN_NEEDED_INPUT definition missing"
 138 #elif MIN_NEEDED_INPUT < 1
 139 # error "MIN_NEEDED_INPUT must be >= 1"
 140 #endif
 141
 142 /* Let's see how many bytes we produce.  */
 143 #ifndef MAX_NEEDED_INPUT
 144 # define MAX_NEEDED_INPUT       MIN_NEEDED_INPUT
 145 #endif
 146
 147 /* We produce at least one byte in the next round.  */
 148 #ifndef MIN_NEEDED_OUTPUT
 149 # error "MIN_NEEDED_OUTPUT definition missing"
 150 #elif MIN_NEEDED_OUTPUT < 1
 151 # error "MIN_NEEDED_OUTPUT must be >= 1"
 152 #endif
 153
 154 /* Let's see how many bytes we produce.  */
 155 #ifndef MAX_NEEDED_OUTPUT
 156 # define MAX_NEEDED_OUTPUT      MIN_NEEDED_OUTPUT
 157 #endif
 158
 159 /* Default name for the function.  */
 160 #ifndef LOOPFCT
 161 # define LOOPFCT                loop
 162 #endif
 163
 164 /* Make sure we have a loop body.  */
 165 #ifndef BODY
 166 # error "Definition of BODY missing for function" LOOPFCT
 167 #endif
 168
 169
 170 /* If no arguments have to passed to the loop function define the macro
 171    as empty.  */
 172 #ifndef EXTRA_LOOP_DECLS
 173 # define EXTRA_LOOP_DECLS
 174 #endif
 175
 176 /* Allow using UPDATE_PARAMS in macros where #ifdef UPDATE_PARAMS test
 177    isn't possible.  */
 178 #ifndef UPDATE_PARAMS
 179 # define UPDATE_PARAMS do { } while (0)
 180 #endif
 181 #ifndef REINIT_PARAMS
 182 # define REINIT_PARAMS do { } while (0)
 183 #endif
 184
 185
 186 /* To make it easier for the writers of the modules, we define a macro
 187    to test whether we have to ignore errors.  */
 188 #define ignore_errors_p() \
 189   (irreversible != NULL && (flags & __GCONV_IGNORE_ERRORS))
 190
 191
 192 /* Error handling for the FROM_LOOP direction, with ignoring of errors.
 193    Note that we cannot use the do while (0) trick since `break' and
 194    `continue' must reach certain points.  */
 195 #define STANDARD_FROM_LOOP_ERR_HANDLER(Incr) \
 196   {                                                                           \
 197     result = __GCONV_ILLEGAL_INPUT;                                           \
 198                                                                               \
 199     if (! ignore_errors_p ())                                                 \
 200       break;                                                                  \
 201                                                                               \
 202     /* We ignore the invalid input byte sequence.  */                         \
 203     inptr += (Incr);                                                          \
 204     ++*irreversible;                                                          \
 205     /* But we keep result == __GCONV_ILLEGAL_INPUT, because of the constraint \
 206        that "iconv -c" must give the same exitcode as "iconv".  */            \
 207     continue;                                                                 \
 208   }
 209
 210 /* Error handling for the TO_LOOP direction, with use of transliteration/
 211    transcription functions and ignoring of errors.  Note that we cannot use
 212    the do while (0) trick since `break' and `continue' must reach certain
 213    points.  */
 214 #define STANDARD_TO_LOOP_ERR_HANDLER(Incr) \
 215   {                                                                           \
 216     result = __GCONV_ILLEGAL_INPUT;                                           \
 217                                                                               \
 218     if (irreversible == NULL)                                                 \
 219       /* This means we are in call from __gconv_transliterate.  In this       \
 220          case we are not doing any error recovery outself.  */                \
 221       break;                                                                  \
 222                                                                               \
 223     /* If needed, flush any conversion state, so that __gconv_transliterate   \
 224        starts with current shift state.  */                                   \
 225     UPDATE_PARAMS;                                                            \
 226                                                                               \
 227     /* First try the transliteration methods.  */                             \
 228     if ((step_data->__flags & __GCONV_TRANSLIT) != 0)                         \
 229       result = __gconv_transliterate                                          \
 230         (step, step_data, *inptrp,                                            \
 231          &inptr, inend, &outptr, irreversible);                       \
 232                                                                               \
 233     REINIT_PARAMS;                                                            \
 234                                                                               \
 235     /* If any of them recognized the input continue with the loop.  */        \
 236     if (result != __GCONV_ILLEGAL_INPUT)                                      \
 237       {                                                                       \
 238         if (__glibc_unlikely (result == __GCONV_FULL_OUTPUT))                 \
 239           break;                                                              \
 240                                                                               \
 241         continue;                                                             \
 242       }                                                                       \
 243                                                                               \
 244     /* Next see whether we have to ignore the error.  If not, stop.  */       \
 245     if (! ignore_errors_p ())                                                 \
 246       break;                                                                  \
 247                                                                               \
 248     /* When we come here it means we ignore the character.  */                \
 249     ++*irreversible;                                                          \
 250     inptr += Incr;                                                            \
 251     /* But we keep result == __GCONV_ILLEGAL_INPUT, because of the constraint \
 252        that "iconv -c" must give the same exitcode as "iconv".  */            \
 253     continue;                                                                 \
 254   }
 255
 256
 257 /* Handling of Unicode 3.1 TAG characters.  Unicode recommends
 258    "If language codes are not relevant to the particular processing
 259     operation, then they should be ignored."  This macro is usually
 260    called right before  STANDARD_TO_LOOP_ERR_HANDLER (Incr).  */
 261 #define UNICODE_TAG_HANDLER(Character, Incr) \
 262   {                                                                           \
 263     /* TAG characters are those in the range U+E0000..U+E007F.  */            \
 264     if (((Character) >> 7) == (0xe0000 >> 7))                                 \
 265       {                                                                       \
 266         inptr += Incr;                                                        \
 267         continue;                                                             \
 268       }                                                                       \
 269   }
 270
 271
 272 /* The function returns the status, as defined in gconv.h.  */
 273 static inline int
 274 __attribute ((always_inline))
 275 FCTNAME (LOOPFCT) (struct __gconv_step *step,
 276                    struct __gconv_step_data *step_data,
 277                    const unsigned char **inptrp, const unsigned char *inend,
 278                    unsigned char **outptrp, const unsigned char *outend,
 279                    size_t *irreversible EXTRA_LOOP_DECLS)
 280 {
 281 #ifdef LOOP_NEED_STATE
 282   mbstate_t *state = step_data->__statep;
 283 #endif
 284 #ifdef LOOP_NEED_FLAGS
 285   int flags = step_data->__flags;
 286 #endif
 287 #ifdef LOOP_NEED_DATA
 288   void *data = step->__data;
 289 #endif
 290   int result = __GCONV_EMPTY_INPUT;
 291   const unsigned char *inptr = *inptrp;
 292   unsigned char *outptr = *outptrp;
 293
 294 #ifdef INIT_PARAMS
 295   INIT_PARAMS;
 296 #endif
 297
 298   while (inptr != inend)
 299     {
 300       /* `if' cases for MIN_NEEDED_OUTPUT ==/!= 1 is made to help the
 301          compiler generating better code.  They will be optimized away
 302          since MIN_NEEDED_OUTPUT is always a constant.  */
 303       if (MIN_NEEDED_INPUT > 1
 304           && __builtin_expect (inptr + MIN_NEEDED_INPUT > inend, 0))
 305         {
 306           /* We don't have enough input for another complete input
 307              character.  */
 308           result = __GCONV_INCOMPLETE_INPUT;
 309           break;
 310         }
 311       if ((MIN_NEEDED_OUTPUT != 1
 312            && __builtin_expect (outptr + MIN_NEEDED_OUTPUT > outend, 0))
 313           || (MIN_NEEDED_OUTPUT == 1
 314               && __builtin_expect (outptr >= outend, 0)))
 315         {
 316           /* Overflow in the output buffer.  */
 317           result = __GCONV_FULL_OUTPUT;
 318           break;
 319         }
 320
 321       /* Here comes the body the user provides.  It can stop with
 322          RESULT set to GCONV_INCOMPLETE_INPUT (if the size of the
 323          input characters vary in size), GCONV_ILLEGAL_INPUT, or
 324          GCONV_FULL_OUTPUT (if the output characters vary in size).  */
 325       BODY
 326     }
 327
 328   /* Update the pointers pointed to by the parameters.  */
 329   *inptrp = inptr;
 330   *outptrp = outptr;
 331   UPDATE_PARAMS;
 332
 333   return result;
 334 }
 335
 336
 337 /* Include the file a second time to define the function to handle
 338    unaligned access.  */
 339 #if !defined DEFINE_UNALIGNED && !_STRING_ARCH_unaligned \
 340     && MIN_NEEDED_INPUT != 1 && MAX_NEEDED_INPUT % MIN_NEEDED_INPUT == 0 \
 341     && MIN_NEEDED_OUTPUT != 1 && MAX_NEEDED_OUTPUT % MIN_NEEDED_OUTPUT == 0
 342 # undef get16
 343 # undef get32
 344 # undef put16
 345 # undef put32
 346 # undef unaligned
 347
 348 # define DEFINE_UNALIGNED
 349 # include "loop.c"
 350 # undef DEFINE_UNALIGNED
 351 #else
 352 # if MAX_NEEDED_INPUT > 1
 353 #  define SINGLE(fct) SINGLE2 (fct)
 354 #  define SINGLE2(fct) fct##_single
 355 static inline int
 356 __attribute ((always_inline))
 357 SINGLE(LOOPFCT) (struct __gconv_step *step,
 358                  struct __gconv_step_data *step_data,
 359                  const unsigned char **inptrp, const unsigned char *inend,
 360                  unsigned char **outptrp, unsigned char *outend,
 361                  size_t *irreversible EXTRA_LOOP_DECLS)
 362 {
 363   mbstate_t *state = step_data->__statep;
 364 #  ifdef LOOP_NEED_FLAGS
 365   int flags = step_data->__flags;
 366 #  endif
 367 #  ifdef LOOP_NEED_DATA
 368   void *data = step->__data;
 369 #  endif
 370   int result = __GCONV_OK;
 371   unsigned char bytebuf[MAX_NEEDED_INPUT];
 372   const unsigned char *inptr = *inptrp;
 373   unsigned char *outptr = *outptrp;
 374   size_t inlen;
 375
 376 #  ifdef INIT_PARAMS
 377   INIT_PARAMS;
 378 #  endif
 379
 380 #  ifdef UNPACK_BYTES
 381   UNPACK_BYTES
 382 #  else
 383   /* Add the bytes from the state to the input buffer.  */
 384   assert ((state->__count & 7) <= sizeof (state->__value));
 385   for (inlen = 0; inlen < (size_t) (state->__count & 7); ++inlen)
 386     bytebuf[inlen] = state->__value.__wchb[inlen];
 387 #  endif
 388
 389   /* Are there enough bytes in the input buffer?  */
 390   if (MIN_NEEDED_INPUT > 1
 391       && __builtin_expect (inptr + (MIN_NEEDED_INPUT - inlen) > inend, 0))
 392     {
 393       *inptrp = inend;
 394 #  ifdef STORE_REST
 395
 396       /* Building with -O3 GCC emits a `array subscript is above array
 397          bounds' warning.  GCC BZ #64739 has been opened for this.  */
 398       DIAG_PUSH_NEEDS_COMMENT;
 399       DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Warray-bounds");
 400       while (inptr < inend)
 401         bytebuf[inlen++] = *inptr++;
 402       DIAG_POP_NEEDS_COMMENT;
 403
 404       inptr = bytebuf;
 405       inptrp = &inptr;
 406       inend = &bytebuf[inlen];
 407
 408       STORE_REST
 409 #  else
 410       /* We don't have enough input for another complete input
 411          character.  */
 412       while (inptr < inend)
 413         state->__value.__wchb[inlen++] = *inptr++;
 414 #  endif
 415
 416       return __GCONV_INCOMPLETE_INPUT;
 417     }
 418
 419   /* Enough space in output buffer.  */
 420   if ((MIN_NEEDED_OUTPUT != 1 && outptr + MIN_NEEDED_OUTPUT > outend)
 421       || (MIN_NEEDED_OUTPUT == 1 && outptr >= outend))
 422     /* Overflow in the output buffer.  */
 423     return __GCONV_FULL_OUTPUT;
 424
 425   /*  Now add characters from the normal input buffer.  */
 426   do
 427     bytebuf[inlen++] = *inptr++;
 428   while (inlen < MAX_NEEDED_INPUT && inptr < inend);
 429
 430   inptr = bytebuf;
 431   inend = &bytebuf[inlen];
 432
 433   do
 434     {
 435       BODY
 436     }
 437   while (0);
 438
 439   /* Now we either have produced an output character and consumed all the
 440      bytes from the state and at least one more, or the character is still
 441      incomplete, or we have some other error (like illegal input character,
 442      no space in output buffer).  */
 443   if (__glibc_likely (inptr != bytebuf))
 444     {
 445       /* We found a new character.  */
 446       assert (inptr - bytebuf > (state->__count & 7));
 447
 448       *inptrp += inptr - bytebuf - (state->__count & 7);
 449       *outptrp = outptr;
 450
 451       result = __GCONV_OK;
 452
 453       /* Clear the state buffer.  */
 454 #  ifdef CLEAR_STATE
 455       CLEAR_STATE;
 456 #  else
 457       state->__count &= ~7;
 458 #  endif
 459     }
 460   else if (result == __GCONV_INCOMPLETE_INPUT)
 461     {
 462       /* This can only happen if we have less than MAX_NEEDED_INPUT bytes
 463          available.  */
 464       assert (inend != &bytebuf[MAX_NEEDED_INPUT]);
 465
 466       *inptrp += inend - bytebuf - (state->__count & 7);
 467 #  ifdef STORE_REST
 468       inptrp = &inptr;
 469
 470       STORE_REST
 471 #  else
 472       /* We don't have enough input for another complete input
 473          character.  */
 474       assert (inend - inptr > (state->__count & ~7));
 475       assert (inend - inptr <= sizeof (state->__value));
 476       state->__count = (state->__count & ~7) | (inend - inptr);
 477       inlen = 0;
 478       while (inptr < inend)
 479         state->__value.__wchb[inlen++] = *inptr++;
 480 #  endif
 481     }
 482
 483   return result;
 484 }
 485 #  undef SINGLE
 486 #  undef SINGLE2
 487 # endif
 488
 489
 490 # ifdef ONEBYTE_BODY
 491 /* Define the shortcut function for btowc.  */
 492 static wint_t
 493 gconv_btowc (struct __gconv_step *step, unsigned char c)
 494   ONEBYTE_BODY
 495 #  define FROM_ONEBYTE gconv_btowc
 496 # endif
 497
 498 #endif
 499
 500 /* We remove the macro definitions so that we can include this file again
 501    for the definition of another function.  */
 502 #undef MIN_NEEDED_INPUT
 503 #undef MAX_NEEDED_INPUT
 504 #undef MIN_NEEDED_OUTPUT
 505 #undef MAX_NEEDED_OUTPUT
 506 #undef LOOPFCT
 507 #undef BODY
 508 #undef LOOPFCT
 509 #undef EXTRA_LOOP_DECLS
 510 #undef INIT_PARAMS
 511 #undef UPDATE_PARAMS
 512 #undef REINIT_PARAMS
 513 #undef ONEBYTE_BODY
 514 #undef UNPACK_BYTES
 515 #undef CLEAR_STATE
 516 #undef LOOP_NEED_STATE
 517 #undef LOOP_NEED_FLAGS
 518 #undef LOOP_NEED_DATA
 519 #undef get16
 520 #undef get32
 521 #undef put16
 522 #undef put32
 523 #undef unaligned