azio.c 17.7 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
/*
  azio is a modified version of gzio. It  makes use of mysys and removes mallocs.
*/

/* gzio.c -- IO on .gz files
 * Copyright (C) 1995-2005 Jean-loup Gailly.
 * For conditions of distribution and use, see copyright notice in zlib.h
 *
 * Compile this file with -DNO_GZCOMPRESS to avoid the compression code.
 */

/* @(#) $Id$ */

#include <stdio.h>

#include "azlib.h"

static int const gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */

/* gzip flag byte */
#define ASCII_FLAG   0x01 /* bit 0 set: file probably ascii text */
#define HEAD_CRC     0x02 /* bit 1 set: header CRC present */
#define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
#define ORIG_NAME    0x08 /* bit 3 set: original file name present */
#define COMMENT      0x10 /* bit 4 set: file comment present */
#define RESERVED     0xE0 /* bits 5..7: reserved */

28 29 30 31 32 33 34
int az_open(azio_stream *s, const char *path, int Flags, File  fd);
int do_flush(azio_stream *file, int flush);
int    get_byte(azio_stream *s);
void   check_header(azio_stream *s);
int    destroy(azio_stream *s);
void putLong(File file, uLong x);
uLong  getLong(azio_stream *s);
35 36 37 38 39 40 41 42 43 44

/* ===========================================================================
  Opens a gzip (.gz) file for reading or writing. The mode parameter
  is as in fopen ("rb" or "wb"). The file is given either by file descriptor
  or path name (if fd == -1).
  az_open returns NULL if the file could not be opened or if there was
  insufficient memory to allocate the (de)compression state; errno
  can be checked to distinguish the two cases (if errno is zero, the
  zlib error is Z_MEM_ERROR).
*/
45
int az_open (azio_stream *s, const char *path, int Flags, File fd)
46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156
{
  int err;
  int level = Z_DEFAULT_COMPRESSION; /* compression level */
  int strategy = Z_DEFAULT_STRATEGY; /* compression strategy */

  s->stream.zalloc = (alloc_func)0;
  s->stream.zfree = (free_func)0;
  s->stream.opaque = (voidpf)0;
  zmemzero(s->inbuf, Z_BUFSIZE);
  zmemzero(s->outbuf, Z_BUFSIZE);
  s->stream.next_in = s->inbuf;
  s->stream.next_out = s->outbuf;
  s->stream.avail_in = s->stream.avail_out = 0;
  s->z_err = Z_OK;
  s->z_eof = 0;
  s->in = 0;
  s->out = 0;
  s->back = EOF;
  s->crc = crc32(0L, Z_NULL, 0);
  s->transparent = 0;
  s->mode = 'r';

  if (Flags & O_WRONLY || Flags & O_APPEND) 
    s->mode = 'w';

  if (s->mode == 'w') {
#ifdef NO_GZCOMPRESS
    err = Z_STREAM_ERROR;
#else
    err = deflateInit2(&(s->stream), level,
                       Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL, strategy);
    /* windowBits is passed < 0 to suppress zlib header */

    s->stream.next_out = s->outbuf;
#endif
    if (err != Z_OK)
    {
      destroy(s);
      return Z_NULL;
    }
  } else {
    s->stream.next_in  = s->inbuf;

    err = inflateInit2(&(s->stream), -MAX_WBITS);
    /* windowBits is passed < 0 to tell that there is no zlib header.
     * Note that in this case inflate *requires* an extra "dummy" byte
     * after the compressed stream in order to complete decompression and
     * return Z_STREAM_END. Here the gzip CRC32 ensures that 4 bytes are
     * present after the compressed stream.
   */
    if (err != Z_OK)
    {
      destroy(s);
      return Z_NULL;
    }
  }
  s->stream.avail_out = Z_BUFSIZE;

  errno = 0;
  s->file = fd < 0 ? my_open(path, Flags, MYF(0)) : fd;

  if (s->file < 0 ) 
  {
    destroy(s);
    return Z_NULL;
  }
  if (s->mode == 'w') {
    char buffer[10];
    /* Write a very simple .gz header:
  */
    snprintf(buffer, 10, "%c%c%c%c%c%c%c%c%c%c", gz_magic[0], gz_magic[1],
            Z_DEFLATED, 0 /*flags*/, 0,0,0,0 /*time*/, 0 /*xflags*/, OS_CODE);
    s->start = 10L;
    my_write(s->file, buffer, s->start, MYF(0));
    /* We use 10L instead of ftell(s->file) to because ftell causes an
     * fflush on some systems. This version of the library doesn't use
     * start anyway in write mode, so this initialization is not
     * necessary.
   */
  } else {
    check_header(s); /* skip the .gz header */
    s->start = my_tell(s->file, MYF(0)) - s->stream.avail_in;
  }

  return 1;
}

/* ===========================================================================
  Opens a gzip (.gz) file for reading or writing.
*/
int azopen(azio_stream *s, const char *path, int Flags)
{
  return az_open(s, path, Flags, -1);
}

/* ===========================================================================
  Associate a gzFile with the file descriptor fd. fd is not dup'ed here
  to mimic the behavio(u)r of fdopen.
*/
int azdopen(azio_stream *s, File fd, int Flags)
{
  if (fd < 0) return 0;

  return az_open (s, NULL, Flags, fd);
}

/* ===========================================================================
  Read a byte from a azio_stream; update next_in and avail_in. Return EOF
  for end of file.
  IN assertion: the stream s has been sucessfully opened for reading.
*/
157
int get_byte(s)
158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185
  azio_stream *s;
{
  if (s->z_eof) return EOF;
  if (s->stream.avail_in == 0) 
  {
    errno = 0;
    s->stream.avail_in = my_read(s->file, (byte *)s->inbuf, Z_BUFSIZE, MYF(0));
    if (s->stream.avail_in == 0) 
    {
      s->z_eof = 1;
      // if (ferror(s->file)) s->z_err = Z_ERRNO;
      return EOF;
    }
    s->stream.next_in = s->inbuf;
  }
  s->stream.avail_in--;
  return *(s->stream.next_in)++;
}

/* ===========================================================================
  Check the gzip header of a azio_stream opened for reading. Set the stream
  mode to transparent if the gzip magic header is not present; set s->err
  to Z_DATA_ERROR if the magic header is present but the rest of the header
  is incorrect.
  IN assertion: the stream s has already been created sucessfully;
  s->stream.avail_in is zero for the first time, but may be non-zero
  for concatenated .gz files.
*/
186
void check_header(azio_stream *s)
187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251
{
  int method; /* method byte */
  int flags;  /* flags byte */
  uInt len;
  int c;

  /* Assure two bytes in the buffer so we can peek ahead -- handle case
    where first byte of header is at the end of the buffer after the last
    gzip segment */
  len = s->stream.avail_in;
  if (len < 2) {
    if (len) s->inbuf[0] = s->stream.next_in[0];
    errno = 0;
    len = (uInt)my_read(s->file, (byte *)s->inbuf + len, Z_BUFSIZE >> len, MYF(0));
    if (len == 0) s->z_err = Z_ERRNO;
    s->stream.avail_in += len;
    s->stream.next_in = s->inbuf;
    if (s->stream.avail_in < 2) {
      s->transparent = s->stream.avail_in;
      return;
    }
  }

  /* Peek ahead to check the gzip magic header */
  if (s->stream.next_in[0] != gz_magic[0] ||
      s->stream.next_in[1] != gz_magic[1]) {
    s->transparent = 1;
    return;
  }
  s->stream.avail_in -= 2;
  s->stream.next_in += 2;

  /* Check the rest of the gzip header */
  method = get_byte(s);
  flags = get_byte(s);
  if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
    s->z_err = Z_DATA_ERROR;
    return;
  }

  /* Discard time, xflags and OS code: */
  for (len = 0; len < 6; len++) (void)get_byte(s);

  if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
    len  =  (uInt)get_byte(s);
    len += ((uInt)get_byte(s))<<8;
    /* len is garbage if EOF but the loop below will quit anyway */
    while (len-- != 0 && get_byte(s) != EOF) ;
  }
  if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
    while ((c = get_byte(s)) != 0 && c != EOF) ;
  }
  if ((flags & COMMENT) != 0) {   /* skip the .gz file comment */
    while ((c = get_byte(s)) != 0 && c != EOF) ;
  }
  if ((flags & HEAD_CRC) != 0) {  /* skip the header crc */
    for (len = 0; len < 2; len++) (void)get_byte(s);
  }
  s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK;
}

/* ===========================================================================
 * Cleanup then free the given azio_stream. Return a zlib error code.
 Try freeing in the reverse order of allocations.
 */
252
int destroy (s)
253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269
  azio_stream *s;
{
  int err = Z_OK;

  if (s->stream.state != NULL) {
    if (s->mode == 'w') {
#ifdef NO_GZCOMPRESS
      err = Z_STREAM_ERROR;
#else
      err = deflateEnd(&(s->stream));
#endif
    } 
    else if (s->mode == 'r') 
    {
      err = inflateEnd(&(s->stream));
    }
  }
270
  if (s->file > 0 && my_close(s->file, MYF(0))) 
271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427
  {
#ifdef ESPIPE
    if (errno != ESPIPE) /* fclose is broken for pipes in HP/UX */
#endif
      err = Z_ERRNO;
  }
  if (s->z_err < 0) err = s->z_err;

  return err;
}

/* ===========================================================================
  Reads the given number of uncompressed bytes from the compressed file.
  azread returns the number of bytes actually read (0 for end of file).
*/
int ZEXPORT azread ( azio_stream *s, voidp buf, unsigned len)
{
  Bytef *start = (Bytef*)buf; /* starting point for crc computation */
  Byte  *next_out; /* == stream.next_out but not forced far (for MSDOS) */

  if (s->mode != 'r') return Z_STREAM_ERROR;

  if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO) return -1;
  if (s->z_err == Z_STREAM_END) return 0;  /* EOF */

  next_out = (Byte*)buf;
  s->stream.next_out = (Bytef*)buf;
  s->stream.avail_out = len;

  if (s->stream.avail_out && s->back != EOF) {
    *next_out++ = s->back;
    s->stream.next_out++;
    s->stream.avail_out--;
    s->back = EOF;
    s->out++;
    start++;
    if (s->last) {
      s->z_err = Z_STREAM_END;
      return 1;
    }
  }

  while (s->stream.avail_out != 0) {

    if (s->transparent) {
      /* Copy first the lookahead bytes: */
      uInt n = s->stream.avail_in;
      if (n > s->stream.avail_out) n = s->stream.avail_out;
      if (n > 0) {
        zmemcpy(s->stream.next_out, s->stream.next_in, n);
        next_out += n;
        s->stream.next_out = (Bytef *)next_out;
        s->stream.next_in   += n;
        s->stream.avail_out -= n;
        s->stream.avail_in  -= n;
      }
      if (s->stream.avail_out > 0) 
      {
        s->stream.avail_out -=
          (uInt)my_read(s->file, (byte *)next_out, s->stream.avail_out, MYF(0));
      }
      len -= s->stream.avail_out;
      s->in  += len;
      s->out += len;
      if (len == 0) s->z_eof = 1;
      return (int)len;
    }
    if (s->stream.avail_in == 0 && !s->z_eof) {

      errno = 0;
      s->stream.avail_in = (uInt)my_read(s->file, (byte *)s->inbuf, Z_BUFSIZE, MYF(0));
      if (s->stream.avail_in == 0) 
      {
        s->z_eof = 1;
      }
      s->stream.next_in = (Bytef *)s->inbuf;
    }
    s->in += s->stream.avail_in;
    s->out += s->stream.avail_out;
    s->z_err = inflate(&(s->stream), Z_NO_FLUSH);
    s->in -= s->stream.avail_in;
    s->out -= s->stream.avail_out;

    if (s->z_err == Z_STREAM_END) {
      /* Check CRC and original size */
      s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
      start = s->stream.next_out;

      if (getLong(s) != s->crc) {
        s->z_err = Z_DATA_ERROR;
      } else {
        (void)getLong(s);
        /* The uncompressed length returned by above getlong() may be
         * different from s->out in case of concatenated .gz files.
         * Check for such files:
       */
        check_header(s);
        if (s->z_err == Z_OK) {
          inflateReset(&(s->stream));
          s->crc = crc32(0L, Z_NULL, 0);
        }
      }
    }
    if (s->z_err != Z_OK || s->z_eof) break;
  }
  s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));

  if (len == s->stream.avail_out &&
      (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO))
    return -1;
  return (int)(len - s->stream.avail_out);
}


#ifndef NO_GZCOMPRESS
/* ===========================================================================
  Writes the given number of uncompressed bytes into the compressed file.
  azwrite returns the number of bytes actually written (0 in case of error).
*/
int azwrite (azio_stream *s, voidpc buf, unsigned len)
{

  s->stream.next_in = (Bytef*)buf;
  s->stream.avail_in = len;

  while (s->stream.avail_in != 0) 
  {
    if (s->stream.avail_out == 0) 
    {

      s->stream.next_out = s->outbuf;
      if (my_write(s->file, (byte *)s->outbuf, Z_BUFSIZE, MYF(0)) != Z_BUFSIZE) 
      {
        s->z_err = Z_ERRNO;
        break;
      }
      s->stream.avail_out = Z_BUFSIZE;
    }
    s->in += s->stream.avail_in;
    s->out += s->stream.avail_out;
    s->z_err = deflate(&(s->stream), Z_NO_FLUSH);
    s->in -= s->stream.avail_in;
    s->out -= s->stream.avail_out;
    if (s->z_err != Z_OK) break;
  }
  s->crc = crc32(s->crc, (const Bytef *)buf, len);

  return (int)(len - s->stream.avail_in);
}

#endif


/* ===========================================================================
  Flushes all pending output into the compressed file. The parameter
  flush is as in the deflate() function.
*/
428
int do_flush (s, flush)
429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507
  azio_stream *s;
  int flush;
{
  uInt len;
  int done = 0;

  if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;

  s->stream.avail_in = 0; /* should be zero already anyway */

  for (;;) {
    len = Z_BUFSIZE - s->stream.avail_out;

    if (len != 0) {
      if ((uInt)my_write(s->file, (byte *)s->outbuf, len, MYF(0)) != len) 
      {
        s->z_err = Z_ERRNO;
        return Z_ERRNO;
      }
      s->stream.next_out = s->outbuf;
      s->stream.avail_out = Z_BUFSIZE;
    }
    if (done) break;
    s->out += s->stream.avail_out;
    s->z_err = deflate(&(s->stream), flush);
    s->out -= s->stream.avail_out;

    /* Ignore the second of two consecutive flushes: */
    if (len == 0 && s->z_err == Z_BUF_ERROR) s->z_err = Z_OK;

    /* deflate has finished flushing only when it hasn't used up
     * all the available space in the output buffer:
   */
    done = (s->stream.avail_out != 0 || s->z_err == Z_STREAM_END);

    if (s->z_err != Z_OK && s->z_err != Z_STREAM_END) break;
  }
  return  s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
}

int ZEXPORT azflush (s, flush)
  azio_stream *s;
  int flush;
{
  int err = do_flush (s, flush);

  if (err) return err;
  my_sync(s->file, MYF(0));
  return  s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
}

/* ===========================================================================
  Rewinds input file.
*/
int azrewind (s)
  azio_stream *s;
{
  if (s == NULL || s->mode != 'r') return -1;

  s->z_err = Z_OK;
  s->z_eof = 0;
  s->back = EOF;
  s->stream.avail_in = 0;
  s->stream.next_in = (Bytef *)s->inbuf;
  s->crc = crc32(0L, Z_NULL, 0);
  if (!s->transparent) (void)inflateReset(&s->stream);
  s->in = 0;
  s->out = 0;
  return my_seek(s->file, s->start, MY_SEEK_SET, MYF(0));
}

/* ===========================================================================
  Sets the starting position for the next azread or azwrite on the given
  compressed file. The offset represents a number of bytes in the
  azseek returns the resulting offset location as measured in bytes from
  the beginning of the uncompressed stream, or -1 in case of error.
  SEEK_END is not implemented, returns error.
  In this version of the library, azseek can be extremely slow.
*/
508
my_off_t azseek (s, offset, whence)
509
  azio_stream *s;
510
  my_off_t offset;
511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588
  int whence;
{

  if (s == NULL || whence == SEEK_END ||
      s->z_err == Z_ERRNO || s->z_err == Z_DATA_ERROR) {
    return -1L;
  }

  if (s->mode == 'w') {
#ifdef NO_GZCOMPRESS
    return -1L;
#else
    if (whence == SEEK_SET) {
      offset -= s->in;
    }

    /* At this point, offset is the number of zero bytes to write. */
    /* There was a zmemzero here if inbuf was null -Brian */
    while (offset > 0)  {
      uInt size = Z_BUFSIZE;
      if (offset < Z_BUFSIZE) size = (uInt)offset;

      size = azwrite(s, s->inbuf, size);
      if (size == 0) return -1L;

      offset -= size;
    }
    return s->in;
#endif
  }
  /* Rest of function is for reading only */

  /* compute absolute position */
  if (whence == SEEK_CUR) {
    offset += s->out;
  }

  if (s->transparent) {
    /* map to my_seek */
    s->back = EOF;
    s->stream.avail_in = 0;
    s->stream.next_in = (Bytef *)s->inbuf;
    if (my_seek(s->file, offset, MY_SEEK_SET, MYF(0)) == MY_FILEPOS_ERROR) return -1L;

    s->in = s->out = offset;
    return offset;
  }

  /* For a negative seek, rewind and use positive seek */
  if (offset >= s->out) {
    offset -= s->out;
  } else if (azrewind(s) < 0) {
    return -1L;
  }
  /* offset is now the number of bytes to skip. */

  if (offset && s->back != EOF) {
    s->back = EOF;
    s->out++;
    offset--;
    if (s->last) s->z_err = Z_STREAM_END;
  }
  while (offset > 0)  {
    int size = Z_BUFSIZE;
    if (offset < Z_BUFSIZE) size = (int)offset;

    size = azread(s, s->outbuf, (uInt)size);
    if (size <= 0) return -1L;
    offset -= size;
  }
  return s->out;
}

/* ===========================================================================
  Returns the starting position for the next azread or azwrite on the
  given compressed file. This position represents a number of bytes in the
  uncompressed data stream.
*/
589
my_off_t ZEXPORT aztell (file)
590 591 592 593 594 595 596 597 598
  azio_stream *file;
{
  return azseek(file, 0L, SEEK_CUR);
}


/* ===========================================================================
  Outputs a long in LSB order to the given file
*/
599
void putLong (File file, uLong x)
600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615
{
  int n;
  byte buffer[1];

  for (n = 0; n < 4; n++) 
  {
    buffer[0]= (int)(x & 0xff);
    my_write(file, buffer, 1, MYF(0));
    x >>= 8;
  }
}

/* ===========================================================================
  Reads a long in LSB order from the given azio_stream. Sets z_err in case
  of error.
*/
616
uLong getLong (azio_stream *s)
617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650
{
  uLong x = (uLong)get_byte(s);
  int c;

  x += ((uLong)get_byte(s))<<8;
  x += ((uLong)get_byte(s))<<16;
  c = get_byte(s);
  if (c == EOF) s->z_err = Z_DATA_ERROR;
  x += ((uLong)c)<<24;
  return x;
}

/* ===========================================================================
  Flushes all pending output if necessary, closes the compressed file
  and deallocates all the (de)compression state.
*/
int azclose (azio_stream *s)
{

  if (s == NULL) return Z_STREAM_ERROR;

  if (s->mode == 'w') {
#ifdef NO_GZCOMPRESS
    return Z_STREAM_ERROR;
#else
    if (do_flush (s, Z_FINISH) != Z_OK)
      return destroy(s);

    putLong(s->file, s->crc);
    putLong(s->file, (uLong)(s->in & 0xffffffff));
#endif
  }
  return destroy(s);
}