src/zlib/gzio.c

   1 /* gzio.c -- IO on .gz files
   2  * Copyright (C) 1995-1998 Jean-loup Gailly.
   3  * For conditions of distribution and use, see copyright notice in zlib.h
   4  *
   5  * Compile this file with -DNO_DEFLATE to avoid the compression code.
   6  */
   7
   8 /* @(#) $Id$ */
   9
  10 #include <stdio.h>
  11
  12 #include "zutil.h"
  13
  14 struct internal_state {int dummy;}; /* for buggy compilers */
  15
  16 #ifndef Z_BUFSIZE
  17 #  ifdef MAXSEG_64K
  18 #    define Z_BUFSIZE 4096 /* minimize memory usage for 16-bit DOS */
  19 #  else
  20 #    define Z_BUFSIZE 16384
  21 #  endif
  22 #endif
  23 #ifndef Z_PRINTF_BUFSIZE
  24 #  define Z_PRINTF_BUFSIZE 4096
  25 #endif
  26
  27 #define ALLOC(size) malloc(size)
  28 #define TRYFREE(p) {if (p) free(p);}
  29
  30 static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
  31
  32 /* gzip flag byte */
  33 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ascii text */
  34 #define HEAD_CRC     0x02 /* bit 1 set: header CRC present */
  35 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
  36 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
  37 #define COMMENT      0x10 /* bit 4 set: file comment present */
  38 #define RESERVED     0xE0 /* bits 5..7: reserved */
  39
  40 typedef struct gz_stream {
  41     z_stream stream;
  42     int      z_err;   /* error code for last stream operation */
  43     int      z_eof;   /* set if end of input file */
  44     FILE     *file;   /* .gz file */
  45     Byte     *inbuf;  /* input buffer */
  46     Byte     *outbuf; /* output buffer */
  47     uLong    crc;     /* crc32 of uncompressed data */
  48     char     *msg;    /* error message */
  49     char     *path;   /* path name for debugging only */
  50     int      transparent; /* 1 if input file is not a .gz file */
  51     char     mode;    /* 'w' or 'r' */
  52     long     startpos; /* start of compressed data in file (header skipped) */
  53 } gz_stream;
  54
  55
  56 local gzFile gz_open      OF((const char *path, const char *mode, int  fd));
  57 local int do_flush        OF((gzFile file, int flush));
  58 local int    get_byte     OF((gz_stream *s));
  59 local void   check_header OF((gz_stream *s));
  60 local int    destroy      OF((gz_stream *s));
  61 local void   putLong      OF((FILE *file, uLong x));
  62 local uLong  getLong      OF((gz_stream *s));
  63
  64 /* ===========================================================================
  65      Opens a gzip (.gz) file for reading or writing. The mode parameter
  66    is as in fopen ("rb" or "wb"). The file is given either by file descriptor
  67    or path name (if fd == -1).
  68      gz_open return NULL if the file could not be opened or if there was
  69    insufficient memory to allocate the (de)compression state; errno
  70    can be checked to distinguish the two cases (if errno is zero, the
  71    zlib error is Z_MEM_ERROR).
  72 */
  73 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
  74 local gzFile gz_open (const char* path, const char* mode, int fd)
  75 #else
  76 local gzFile gz_open (path, mode, fd)
  77     const char *path;
  78     const char *mode;
  79     int  fd;
  80 #endif
  81 {
  82     int err;
  83     int level = Z_DEFAULT_COMPRESSION; /* compression level */
  84     int strategy = Z_DEFAULT_STRATEGY; /* compression strategy */
  85     char *p = (char*)mode;
  86     gz_stream *s;
  87     char fmode[80]; /* copy of mode, without the compression level */
  88     char *m = fmode;
  89
  90     if (!path || !mode) return Z_NULL;
  91
  92     s = (gz_stream *)ALLOC(sizeof(gz_stream));
  93     if (!s) return Z_NULL;
  94
  95     s->stream.zalloc = (alloc_func)0;
  96     s->stream.zfree = (free_func)0;
  97     s->stream.opaque = (voidpf)0;
  98     s->stream.next_in = s->inbuf = Z_NULL;
  99     s->stream.next_out = s->outbuf = Z_NULL;
 100     s->stream.avail_in = s->stream.avail_out = 0;
 101     s->file = NULL;
 102     s->z_err = Z_OK;
 103     s->z_eof = 0;
 104     s->crc = crc32(0L, Z_NULL, 0);
 105     s->msg = NULL;
 106     s->transparent = 0;
 107
 108     s->path = (char*)ALLOC(strlen(path)+1);
 109     if (s->path == NULL) {
 110         return destroy(s), (gzFile)Z_NULL;
 111     }
 112     strcpy(s->path, path); /* do this early for debugging */
 113
 114     s->mode = '\0';
 115     do {
 116         if (*p == 'r') s->mode = 'r';
 117         if (*p == 'w' || *p == 'a') s->mode = 'w';
 118         if (*p >= '0' && *p <= '9') {
 119             level = *p - '0';
 120         } else if (*p == 'f') {
 121           strategy = Z_FILTERED;
 122         } else if (*p == 'h') {
 123           strategy = Z_HUFFMAN_ONLY;
 124         } else {
 125             *m++ = *p; /* copy the mode */
 126         }
 127     } while (*p++ && m != fmode + sizeof(fmode));
 128     if (s->mode == '\0') return destroy(s), (gzFile)Z_NULL;
 129
 130     if (s->mode == 'w') {
 131 #ifdef NO_DEFLATE
 132         err = Z_STREAM_ERROR;
 133 #else
 134         err = deflateInit2(&(s->stream), level,
 135                            Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL, strategy);
 136         /* windowBits is passed < 0 to suppress zlib header */
 137
 138         s->stream.next_out = s->outbuf = (Byte*)ALLOC(Z_BUFSIZE);
 139 #endif
 140         if (err != Z_OK || s->outbuf == Z_NULL) {
 141             return destroy(s), (gzFile)Z_NULL;
 142         }
 143     } else {
 144         s->stream.next_in  = s->inbuf = (Byte*)ALLOC(Z_BUFSIZE);
 145
 146         err = inflateInit2(&(s->stream), -MAX_WBITS);
 147         /* windowBits is passed < 0 to tell that there is no zlib header.
 148          * Note that in this case inflate *requires* an extra "dummy" byte
 149          * after the compressed stream in order to complete decompression and
 150          * return Z_STREAM_END. Here the gzip CRC32 ensures that 4 bytes are
 151          * present after the compressed stream.
 152          */
 153         if (err != Z_OK || s->inbuf == Z_NULL) {
 154             return destroy(s), (gzFile)Z_NULL;
 155         }
 156     }
 157     s->stream.avail_out = Z_BUFSIZE;
 158
 159     errno = 0;
 160     s->file = fd < 0 ? F_OPEN(path, fmode) : (FILE*)fdopen(fd, fmode);
 161
 162     if (s->file == NULL) {
 163         return destroy(s), (gzFile)Z_NULL;
 164     }
 165     if (s->mode == 'w') {
 166         /* Write a very simple .gz header:
 167          */
 168         fprintf(s->file, "%c%c%c%c%c%c%c%c%c%c", gz_magic[0], gz_magic[1],
 169              Z_DEFLATED, 0 /*flags*/, 0,0,0,0 /*time*/, 0 /*xflags*/, OS_CODE);
 170         s->startpos = 10L;
 171         /* We use 10L instead of ftell(s->file) to because ftell causes an
 172          * fflush on some systems. This version of the library doesn't use
 173          * startpos anyway in write mode, so this initialization is not
 174          * necessary.
 175          */
 176     } else {
 177         check_header(s); /* skip the .gz header */
 178         s->startpos = (ftell(s->file) - s->stream.avail_in);
 179     }
 180
 181     return (gzFile)s;
 182 }
 183
 184 /* ===========================================================================
 185      Opens a gzip (.gz) file for reading or writing.
 186 */
 187 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 188 gzFile ZEXPORT gzopen (const char* path, const char* mode)
 189 #else
 190 gzFile ZEXPORT gzopen (path, mode)
 191     const char *path;
 192     const char *mode;
 193 #endif
 194 {
 195     return gz_open (path, mode, -1);
 196 }
 197
 198 /* ===========================================================================
 199      Associate a gzFile with the file descriptor fd. fd is not dup'ed here
 200    to mimic the behavio(u)r of fdopen.
 201 */
 202 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 203 gzFile ZEXPORT gzdopen (int fd, const char* mode)
 204 #else
 205 gzFile ZEXPORT gzdopen (fd, mode)
 206     int fd;
 207     const char *mode;
 208 #endif
 209 {
 210     char name[20];
 211
 212     if (fd < 0) return (gzFile)Z_NULL;
 213     sprintf(name, "<fd:%d>", fd); /* for debugging */
 214
 215     return gz_open (name, mode, fd);
 216 }
 217
 218 /* ===========================================================================
 219  * Update the compression level and strategy
 220  */
 221 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 222 int ZEXPORT gzsetparams (gzFile file, int level, int strategy)
 223 #else
 224 int ZEXPORT gzsetparams (file, level, strategy)
 225     gzFile file;
 226     int level;
 227     int strategy;
 228 #endif
 229 {
 230     gz_stream *s = (gz_stream*)file;
 231
 232     if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
 233
 234     /* Make room to allow flushing */
 235     if (s->stream.avail_out == 0) {
 236
 237         s->stream.next_out = s->outbuf;
 238         if (fwrite(s->outbuf, 1, Z_BUFSIZE, s->file) != Z_BUFSIZE) {
 239             s->z_err = Z_ERRNO;
 240         }
 241         s->stream.avail_out = Z_BUFSIZE;
 242     }
 243
 244     return deflateParams (&(s->stream), level, strategy);
 245 }
 246
 247 /* ===========================================================================
 248      Read a byte from a gz_stream; update next_in and avail_in. Return EOF
 249    for end of file.
 250    IN assertion: the stream s has been sucessfully opened for reading.
 251 */
 252 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 253 local int get_byte(gz_stream* s)
 254 #else
 255 local int get_byte(s)
 256     gz_stream *s;
 257 #endif
 258 {
 259     if (s->z_eof) return EOF;
 260     if (s->stream.avail_in == 0) {
 261         errno = 0;
 262         s->stream.avail_in = fread(s->inbuf, 1, Z_BUFSIZE, s->file);
 263         if (s->stream.avail_in == 0) {
 264             s->z_eof = 1;
 265             if (ferror(s->file)) s->z_err = Z_ERRNO;
 266             return EOF;
 267         }
 268         s->stream.next_in = s->inbuf;
 269     }
 270     s->stream.avail_in--;
 271     return *(s->stream.next_in)++;
 272 }
 273
 274 /* ===========================================================================
 275       Check the gzip header of a gz_stream opened for reading. Set the stream
 276     mode to transparent if the gzip magic header is not present; set s->err
 277     to Z_DATA_ERROR if the magic header is present but the rest of the header
 278     is incorrect.
 279     IN assertion: the stream s has already been created sucessfully;
 280        s->stream.avail_in is zero for the first time, but may be non-zero
 281        for concatenated .gz files.
 282 */
 283 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 284 local void check_header(gz_stream* s)
 285 #else
 286 local void check_header(s)
 287     gz_stream *s;
 288 #endif
 289 {
 290     int method; /* method byte */
 291     int flags;  /* flags byte */
 292     uInt len;
 293     int c;
 294
 295     /* Check the gzip magic header */
 296     for (len = 0; len < 2; len++) {
 297         c = get_byte(s);
 298         if (c != gz_magic[len]) {
 299             if (len != 0) s->stream.avail_in++, s->stream.next_in--;
 300             if (c != EOF) {
 301                 s->stream.avail_in++, s->stream.next_in--;
 302                 s->transparent = 1;
 303             }
 304             s->z_err = s->stream.avail_in != 0 ? Z_OK : Z_STREAM_END;
 305             return;
 306         }
 307     }
 308     method = get_byte(s);
 309     flags = get_byte(s);
 310     if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
 311         s->z_err = Z_DATA_ERROR;
 312         return;
 313     }
 314
 315     /* Discard time, xflags and OS code: */
 316     for (len = 0; len < 6; len++) (void)get_byte(s);
 317
 318     if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
 319         len  =  (uInt)get_byte(s);
 320         len += ((uInt)get_byte(s))<<8;
 321         /* len is garbage if EOF but the loop below will quit anyway */
 322         while (len-- != 0 && get_byte(s) != EOF) ;
 323     }
 324     if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
 325         while ((c = get_byte(s)) != 0 && c != EOF) ;
 326     }
 327     if ((flags & COMMENT) != 0) {   /* skip the .gz file comment */
 328         while ((c = get_byte(s)) != 0 && c != EOF) ;
 329     }
 330     if ((flags & HEAD_CRC) != 0) {  /* skip the header crc */
 331         for (len = 0; len < 2; len++) (void)get_byte(s);
 332     }
 333     s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK;
 334 }
 335
 336  /* ===========================================================================
 337  * Cleanup then free the given gz_stream. Return a zlib error code.
 338    Try freeing in the reverse order of allocations.
 339  */
 340 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 341 local int destroy (gz_stream* s)
 342 #else
 343 local int destroy (s)
 344     gz_stream *s;
 345 #endif
 346 {
 347     int err = Z_OK;
 348
 349     if (!s) return Z_STREAM_ERROR;
 350
 351     TRYFREE(s->msg);
 352
 353     if (s->stream.state != NULL) {
 354         if (s->mode == 'w') {
 355 #ifdef NO_DEFLATE
 356             err = Z_STREAM_ERROR;
 357 #else
 358             err = deflateEnd(&(s->stream));
 359 #endif
 360         } else if (s->mode == 'r') {
 361             err = inflateEnd(&(s->stream));
 362         }
 363     }
 364     if (s->file != NULL && fclose(s->file)) {
 365 #ifdef ESPIPE
 366         if (errno != ESPIPE) /* fclose is broken for pipes in HP/UX */
 367 #endif
 368             err = Z_ERRNO;
 369     }
 370     if (s->z_err < 0) err = s->z_err;
 371
 372     TRYFREE(s->inbuf);
 373     TRYFREE(s->outbuf);
 374     TRYFREE(s->path);
 375     TRYFREE(s);
 376     return err;
 377 }
 378
 379 /* ===========================================================================
 380      Reads the given number of uncompressed bytes from the compressed file.
 381    gzread returns the number of bytes actually read (0 for end of file).
 382 */
 383 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 384 int ZEXPORT gzread (gzFile file, voidp buf, unsigned len)
 385 #else
 386 int ZEXPORT gzread (file, buf, len)
 387     gzFile file;
 388     voidp buf;
 389     unsigned len;
 390 #endif
 391 {
 392     gz_stream *s = (gz_stream*)file;
 393     Bytef *start = (Bytef*)buf; /* starting point for crc computation */
 394     Byte  *next_out; /* == stream.next_out but not forced far (for MSDOS) */
 395
 396     if (s == NULL || s->mode != 'r') return Z_STREAM_ERROR;
 397
 398     if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO) return -1;
 399     if (s->z_err == Z_STREAM_END) return 0;  /* EOF */
 400
 401     next_out = (Byte*)buf;
 402     s->stream.next_out = (Bytef*)buf;
 403     s->stream.avail_out = len;
 404
 405     while (s->stream.avail_out != 0) {
 406
 407         if (s->transparent) {
 408             /* Copy first the lookahead bytes: */
 409             uInt n = s->stream.avail_in;
 410             if (n > s->stream.avail_out) n = s->stream.avail_out;
 411             if (n > 0) {
 412                 zmemcpy(s->stream.next_out, s->stream.next_in, n);
 413                 next_out += n;
 414                 s->stream.next_out = next_out;
 415                 s->stream.next_in   += n;
 416                 s->stream.avail_out -= n;
 417                 s->stream.avail_in  -= n;
 418             }
 419             if (s->stream.avail_out > 0) {
 420                 s->stream.avail_out -= fread(next_out, 1, s->stream.avail_out,
 421                                              s->file);
 422             }
 423             len -= s->stream.avail_out;
 424             s->stream.total_in  += (uLong)len;
 425             s->stream.total_out += (uLong)len;
 426             if (len == 0) s->z_eof = 1;
 427             return (int)len;
 428         }
 429         if (s->stream.avail_in == 0 && !s->z_eof) {
 430
 431             errno = 0;
 432             s->stream.avail_in = fread(s->inbuf, 1, Z_BUFSIZE, s->file);
 433             if (s->stream.avail_in == 0) {
 434                 s->z_eof = 1;
 435                 if (ferror(s->file)) {
 436                     s->z_err = Z_ERRNO;
 437                     break;
 438                 }
 439             }
 440             s->stream.next_in = s->inbuf;
 441         }
 442         s->z_err = inflate(&(s->stream), Z_NO_FLUSH);
 443
 444         if (s->z_err == Z_STREAM_END) {
 445             /* Check CRC and original size */
 446             s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
 447             start = s->stream.next_out;
 448
 449             if (getLong(s) != s->crc || getLong(s) != s->stream.total_out) {
 450                 s->z_err = Z_DATA_ERROR;
 451             } else {
 452                 /* Check for concatenated .gz files: */
 453                 check_header(s);
 454                 if (s->z_err == Z_OK) {
 455                     uLong total_in = s->stream.total_in;
 456                     uLong total_out = s->stream.total_out;
 457
 458                     inflateReset(&(s->stream));
 459                     s->stream.total_in = total_in;
 460                     s->stream.total_out = total_out;
 461                     s->crc = crc32(0L, Z_NULL, 0);
 462                 }
 463             }
 464         }
 465         if (s->z_err != Z_OK || s->z_eof) break;
 466     }
 467     s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
 468
 469     return (int)(len - s->stream.avail_out);
 470 }
 471
 472
 473 /* ===========================================================================
 474       Reads one byte from the compressed file. gzgetc returns this byte
 475    or -1 in case of end of file or error.
 476 */
 477 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 478 int ZEXPORT gzgetc(gzFile file)
 479 #else
 480 int ZEXPORT gzgetc(file)
 481     gzFile file;
 482 #endif
 483 {
 484     unsigned char c;
 485
 486     return gzread(file, &c, 1) == 1 ? c : -1;
 487 }
 488
 489
 490 /* ===========================================================================
 491       Reads bytes from the compressed file until len-1 characters are
 492    read, or a newline character is read and transferred to buf, or an
 493    end-of-file condition is encountered.  The string is then terminated
 494    with a null character.
 495       gzgets returns buf, or Z_NULL in case of error.
 496
 497       The current implementation is not optimized at all.
 498 */
 499 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 500 char* ZEXPORT gzgets(gzFile file, char* buf, int len)
 501 #else
 502 char * ZEXPORT gzgets(file, buf, len)
 503     gzFile file;
 504     char *buf;
 505     int len;
 506 #endif
 507 {
 508     char *b = buf;
 509     if (buf == Z_NULL || len <= 0) return Z_NULL;
 510
 511     while (--len > 0 && gzread(file, buf, 1) == 1 && *buf++ != '\n') ;
 512     *buf = '\0';
 513     return b == buf && len > 0 ? Z_NULL : b;
 514 }
 515
 516
 517 #ifndef NO_DEFLATE
 518 /* ===========================================================================
 519      Writes the given number of uncompressed bytes into the compressed file.
 520    gzwrite returns the number of bytes actually written (0 in case of error).
 521 */
 522 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 523 int ZEXPORT gzwrite (gzFile file, const voidp buf, unsigned len)
 524 #else
 525 int ZEXPORT gzwrite (file, buf, len)
 526     gzFile file;
 527     const voidp buf;
 528     unsigned len;
 529 #endif
 530 {
 531     gz_stream *s = (gz_stream*)file;
 532
 533     if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
 534
 535     s->stream.next_in = (Bytef*)buf;
 536     s->stream.avail_in = len;
 537
 538     while (s->stream.avail_in != 0) {
 539
 540         if (s->stream.avail_out == 0) {
 541
 542             s->stream.next_out = s->outbuf;
 543             if (fwrite(s->outbuf, 1, Z_BUFSIZE, s->file) != Z_BUFSIZE) {
 544                 s->z_err = Z_ERRNO;
 545                 break;
 546             }
 547             s->stream.avail_out = Z_BUFSIZE;
 548         }
 549         s->z_err = deflate(&(s->stream), Z_NO_FLUSH);
 550         if (s->z_err != Z_OK) break;
 551     }
 552     s->crc = crc32(s->crc, (const Bytef *)buf, len);
 553
 554     return (int)(len - s->stream.avail_in);
 555 }
 556
 557 /* ===========================================================================
 558      Converts, formats, and writes the args to the compressed file under
 559    control of the format string, as in fprintf. gzprintf returns the number of
 560    uncompressed bytes actually written (0 in case of error).
 561 */
 562 #ifdef STDC
 563 #include <stdarg.h>
 564
 565 int ZEXPORTVA gzprintf (gzFile file, const char *format, /* args */ ...)
 566 {
 567     char buf[Z_PRINTF_BUFSIZE];
 568     va_list va;
 569     int len;
 570
 571     va_start(va, format);
 572 #ifdef HAS_vsnprintf
 573     (void)vsnprintf(buf, sizeof(buf), format, va);
 574 #else
 575     (void)vsprintf(buf, format, va);
 576 #endif
 577     va_end(va);
 578     len = strlen(buf); /* some *sprintf don't return the nb of bytes written */
 579     if (len <= 0) return 0;
 580
 581     return gzwrite(file, buf, (unsigned)len);
 582 }
 583 #else /* not ANSI C */
 584
 585 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 586 int ZEXPORTVA gzprintf (gzFile file const char* format, int a1, int a2, int a3, int a4,
 587                         int a5, int a6, int a7, int a8, int a9, int a10, int a11, int a12
 588                         int a13, int a14, int a15, int a16, int a17, int a18, int a19, int a20)
 589 #else
 590 int ZEXPORTVA gzprintf (file, format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
 591                        a11, a12, a13, a14, a15, a16, a17, a18, a19, a20)
 592     gzFile file;
 593     const char *format;
 594     int a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
 595         a11, a12, a13, a14, a15, a16, a17, a18, a19, a20;
 596 #endif
 597 {
 598     char buf[Z_PRINTF_BUFSIZE];
 599     int len;
 600
 601 #ifdef HAS_snprintf
 602     snprintf(buf, sizeof(buf), format, a1, a2, a3, a4, a5, a6, a7, a8,
 603              a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
 604 #else
 605     sprintf(buf, format, a1, a2, a3, a4, a5, a6, a7, a8,
 606             a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
 607 #endif
 608     len = strlen(buf); /* old sprintf doesn't return the nb of bytes written */
 609     if (len <= 0) return 0;
 610
 611     return gzwrite(file, buf, len);
 612 }
 613 #endif
 614
 615 /* ===========================================================================
 616       Writes c, converted to an unsigned char, into the compressed file.
 617    gzputc returns the value that was written, or -1 in case of error.
 618 */
 619 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 620 int ZEXPORT gzputc(gzFile file, int c)
 621 #else
 622 int ZEXPORT gzputc(file, c)
 623     gzFile file;
 624     int c;
 625 #endif
 626 {
 627     unsigned char cc = (unsigned char) c; /* required for big endian systems */
 628
 629     return gzwrite(file, &cc, 1) == 1 ? (int)cc : -1;
 630 }
 631
 632
 633 /* ===========================================================================
 634       Writes the given null-terminated string to the compressed file, excluding
 635    the terminating null character.
 636       gzputs returns the number of characters written, or -1 in case of error.
 637 */
 638 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 639 int ZEXPORT gzputs(gzFile file, const char* s)
 640 #else
 641 int ZEXPORT gzputs(file, s)
 642     gzFile file;
 643     const char *s;
 644 #endif
 645 {
 646     return gzwrite(file, (char*)s, (unsigned)strlen(s));
 647 }
 648
 649
 650 /* ===========================================================================
 651      Flushes all pending output into the compressed file. The parameter
 652    flush is as in the deflate() function.
 653 */
 654 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 655 local int do_flush (gzFile file, int flush)
 656 #else
 657 local int do_flush (file, flush)
 658     gzFile file;
 659     int flush;
 660 #endif
 661 {
 662     uInt len;
 663     int done = 0;
 664     gz_stream *s = (gz_stream*)file;
 665
 666     if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
 667
 668     s->stream.avail_in = 0; /* should be zero already anyway */
 669
 670     for (;;) {
 671         len = Z_BUFSIZE - s->stream.avail_out;
 672
 673         if (len != 0) {
 674             if ((uInt)fwrite(s->outbuf, 1, len, s->file) != len) {
 675                 s->z_err = Z_ERRNO;
 676                 return Z_ERRNO;
 677             }
 678             s->stream.next_out = s->outbuf;
 679             s->stream.avail_out = Z_BUFSIZE;
 680         }
 681         if (done) break;
 682         s->z_err = deflate(&(s->stream), flush);
 683
 684         /* Ignore the second of two consecutive flushes: */
 685         if (len == 0 && s->z_err == Z_BUF_ERROR) s->z_err = Z_OK;
 686
 687         /* deflate has finished flushing only when it hasn't used up
 688          * all the available space in the output buffer:
 689          */
 690         done = (s->stream.avail_out != 0 || s->z_err == Z_STREAM_END);
 691
 692         if (s->z_err != Z_OK && s->z_err != Z_STREAM_END) break;
 693     }
 694     return  s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
 695 }
 696
 697 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 698 int ZEXPORT gzflush (gzFile file, int flush)
 699 #else
 700 int ZEXPORT gzflush (file, flush)
 701      gzFile file;
 702      int flush;
 703 #endif
 704 {
 705     gz_stream *s = (gz_stream*)file;
 706     int err = do_flush (file, flush);
 707
 708     if (err) return err;
 709     fflush(s->file);
 710     return  s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
 711 }
 712 #endif /* NO_DEFLATE */
 713
 714 /* ===========================================================================
 715       Sets the starting position for the next gzread or gzwrite on the given
 716    compressed file. The offset represents a number of bytes in the
 717       gzseek returns the resulting offset location as measured in bytes from
 718    the beginning of the uncompressed stream, or -1 in case of error.
 719       SEEK_END is not implemented, returns error.
 720       In this version of the library, gzseek can be extremely slow.
 721 */
 722 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 723 z_off_t ZEXPORT gzseek (gzFile file, z_off_t offset, int whence)
 724 #else
 725 z_off_t ZEXPORT gzseek (file, offset, whence)
 726     gzFile file;
 727     z_off_t offset;
 728     int whence;
 729 #endif
 730 {
 731     gz_stream *s = (gz_stream*)file;
 732
 733     if (s == NULL || whence == SEEK_END ||
 734         s->z_err == Z_ERRNO || s->z_err == Z_DATA_ERROR) {
 735         return -1L;
 736     }
 737
 738     if (s->mode == 'w') {
 739 #ifdef NO_DEFLATE
 740         return -1L;
 741 #else
 742         if (whence == SEEK_SET) {
 743             offset -= s->stream.total_out;
 744         }
 745         if (offset < 0) return -1L;
 746
 747         /* At this point, offset is the number of zero bytes to write. */
 748         if (s->inbuf == Z_NULL) {
 749             s->inbuf = (Byte*)ALLOC(Z_BUFSIZE); /* for seeking */
 750             zmemzero(s->inbuf, Z_BUFSIZE);
 751         }
 752         while (offset > 0)  {
 753             uInt size = Z_BUFSIZE;
 754             if (offset < Z_BUFSIZE) size = (uInt)offset;
 755
 756             size = gzwrite(file, s->inbuf, size);
 757             if (size == 0) return -1L;
 758
 759             offset -= size;
 760         }
 761         return (z_off_t)s->stream.total_in;
 762 #endif
 763     }
 764     /* Rest of function is for reading only */
 765
 766     /* compute absolute position */
 767     if (whence == SEEK_CUR) {
 768         offset += s->stream.total_out;
 769     }
 770     if (offset < 0) return -1L;
 771
 772     if (s->transparent) {
 773         /* map to fseek */
 774         s->stream.avail_in = 0;
 775         s->stream.next_in = s->inbuf;
 776         if (fseek(s->file, offset, SEEK_SET) < 0) return -1L;
 777
 778         s->stream.total_in = s->stream.total_out = (uLong)offset;
 779         return offset;
 780     }
 781
 782     /* For a negative seek, rewind and use positive seek */
 783     if ((uLong)offset >= s->stream.total_out) {
 784         offset -= s->stream.total_out;
 785     } else if (gzrewind(file) < 0) {
 786         return -1L;
 787     }
 788     /* offset is now the number of bytes to skip. */
 789
 790     if (offset != 0 && s->outbuf == Z_NULL) {
 791         s->outbuf = (Byte*)ALLOC(Z_BUFSIZE);
 792     }
 793     while (offset > 0)  {
 794         int size = Z_BUFSIZE;
 795         if (offset < Z_BUFSIZE) size = (int)offset;
 796
 797         size = gzread(file, s->outbuf, (uInt)size);
 798         if (size <= 0) return -1L;
 799         offset -= size;
 800     }
 801     return (z_off_t)s->stream.total_out;
 802 }
 803
 804 /* ===========================================================================
 805      Rewinds input file.
 806 */
 807 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 808 int ZEXPORT gzrewind (gzFile file)
 809 #else
 810 int ZEXPORT gzrewind (file)
 811     gzFile file;
 812 #endif
 813 {
 814     gz_stream *s = (gz_stream*)file;
 815
 816     if (s == NULL || s->mode != 'r') return -1;
 817
 818     s->z_err = Z_OK;
 819     s->z_eof = 0;
 820     s->stream.avail_in = 0;
 821     s->stream.next_in = s->inbuf;
 822
 823     if (s->startpos == 0) { /* not a compressed file */
 824         rewind(s->file);
 825         return 0;
 826     }
 827
 828     (void) inflateReset(&s->stream);
 829     return fseek(s->file, s->startpos, SEEK_SET);
 830 }
 831
 832 /* ===========================================================================
 833      Returns the starting position for the next gzread or gzwrite on the
 834    given compressed file. This position represents a number of bytes in the
 835    uncompressed data stream.
 836 */
 837 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 838 z_off_t ZEXPORT gztell (gzFile file)
 839 #else
 840 z_off_t ZEXPORT gztell (file)
 841     gzFile file;
 842 #endif
 843 {
 844     return gzseek(file, 0L, SEEK_CUR);
 845 }
 846
 847 /* ===========================================================================
 848      Returns 1 when EOF has previously been detected reading the given
 849    input stream, otherwise zero.
 850 */
 851 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 852 int ZEXPORT gzeof (gzFile file)
 853 #else
 854 int ZEXPORT gzeof (file)
 855     gzFile file;
 856 #endif
 857 {
 858     gz_stream *s = (gz_stream*)file;
 859
 860     return (s == NULL || s->mode != 'r') ? 0 : s->z_eof;
 861 }
 862
 863 /* ===========================================================================
 864    Outputs a long in LSB order to the given file
 865 */
 866 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 867 local void putLong (FILE* file, uLong x)
 868 #else
 869 local void putLong (file, x)
 870     FILE *file;
 871     uLong x;
 872 #endif
 873 {
 874     int n;
 875     for (n = 0; n < 4; n++) {
 876         fputc((int)(x & 0xff), file);
 877         x >>= 8;
 878     }
 879 }
 880
 881 /* ===========================================================================
 882    Reads a long in LSB order from the given gz_stream. Sets
 883 */
 884 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 885 local uLong getLong (gz_stream* s)
 886 #else
 887 local uLong getLong (s)
 888     gz_stream *s;
 889 #endif
 890 {
 891     uLong x = (uLong)get_byte(s);
 892     int c;
 893
 894     x += ((uLong)get_byte(s))<<8;
 895     x += ((uLong)get_byte(s))<<16;
 896     c = get_byte(s);
 897     if (c == EOF) s->z_err = Z_DATA_ERROR;
 898     x += ((uLong)c)<<24;
 899     return x;
 900 }
 901
 902 /* ===========================================================================
 903      Flushes all pending output if necessary, closes the compressed file
 904    and deallocates all the (de)compression state.
 905 */
 906 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 907 int ZEXPORT gzclose (gzFile file)
 908 #else
 909 int ZEXPORT gzclose (file)
 910     gzFile file;
 911 #endif
 912 {
 913     int err;
 914     gz_stream *s = (gz_stream*)file;
 915
 916     if (s == NULL) return Z_STREAM_ERROR;
 917
 918     if (s->mode == 'w') {
 919 #ifdef NO_DEFLATE
 920         return Z_STREAM_ERROR;
 921 #else
 922         err = do_flush (file, Z_FINISH);
 923         if (err != Z_OK) return destroy((gz_stream*)file);
 924
 925         putLong (s->file, s->crc);
 926         putLong (s->file, s->stream.total_in);
 927 #endif
 928     }
 929     return destroy((gz_stream*)file);
 930 }
 931
 932 /* ===========================================================================
 933      Returns the error message for the last error which occured on the
 934    given compressed file. errnum is set to zlib error number. If an
 935    error occured in the file system and not in the compression library,
 936    errnum is set to Z_ERRNO and the application may consult errno
 937    to get the exact error code.
 938 */
 939 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 940 const char* ZEXPORT gzerror (gzFile file, int* errnum)
 941 #else
 942 const char*  ZEXPORT gzerror (file, errnum)
 943     gzFile file;
 944     int *errnum;
 945 #endif
 946 {
 947     char *m;
 948     gz_stream *s = (gz_stream*)file;
 949
 950     if (s == NULL) {
 951         *errnum = Z_STREAM_ERROR;
 952         return (const char*)ERR_MSG(Z_STREAM_ERROR);
 953     }
 954     *errnum = s->z_err;
 955     if (*errnum == Z_OK) return (const char*)"";
 956
 957     m =  (char*)(*errnum == Z_ERRNO ? zstrerror(errno) : s->stream.msg);
 958
 959     if (m == NULL || *m == '\0') m = (char*)ERR_MSG(s->z_err);
 960
 961     TRYFREE(s->msg);
 962     s->msg = (char*)ALLOC(strlen(s->path) + strlen(m) + 3);
 963     strcpy(s->msg, s->path);
 964     strcat(s->msg, ": ");
 965     strcat(s->msg, m);
 966     return (const char*)s->msg;
 967 }