src/zlib/gzio.c

   1 /* gzio.c -- IO on .gz files
   2  * Copyright (C) 1995-2005 Jean-loup Gailly.
   3  * For conditions of distribution and use, see copyright notice in zlib.h
   4  *
   5  * Compile this file with -DNO_GZCOMPRESS to avoid the compression code.
   6  */
   7
   8 /* @(#) $Id$ */
   9
  10 #include <stdio.h>
  11
  12 #include "zutil.h"
  13
  14 #ifdef NO_DEFLATE       /* for compatibility with old definition */
  15 #  define NO_GZCOMPRESS
  16 #endif
  17
  18 #ifndef NO_DUMMY_DECL
  19 struct internal_state {int dummy;}; /* for buggy compilers */
  20 #endif
  21
  22 #ifndef Z_BUFSIZE
  23 #  ifdef MAXSEG_64K
  24 #    define Z_BUFSIZE 4096 /* minimize memory usage for 16-bit DOS */
  25 #  else
  26 #    define Z_BUFSIZE 16384
  27 #  endif
  28 #endif
  29 #ifndef Z_PRINTF_BUFSIZE
  30 #  define Z_PRINTF_BUFSIZE 4096
  31 #endif
  32
  33 #ifdef __MVS__
  34 #  pragma map (fdopen , "\174\174FDOPEN")
  35    FILE *fdopen(int, const char *);
  36 #endif
  37
  38 #ifndef STDC
  39 extern voidp  malloc OF((uInt size));
  40 extern void   free   OF((voidpf ptr));
  41 #endif
  42
  43 #define ALLOC(size) malloc(size)
  44 #define TRYFREE(p) {if (p) free(p);}
  45
  46 /* there is no errno under Windows CE, provide a dummy one to avoid modifying
  47    too much code in this file */
  48 #ifdef _WIN32_WCE
  49 static int errno;
  50 #endif
  51
  52 static int const gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
  53
  54 /* gzip flag byte */
  55 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ascii text */
  56 #define HEAD_CRC     0x02 /* bit 1 set: header CRC present */
  57 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
  58 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
  59 #define COMMENT      0x10 /* bit 4 set: file comment present */
  60 #define RESERVED     0xE0 /* bits 5..7: reserved */
  61
  62 typedef struct gz_stream {
  63     z_stream stream;
  64     int      z_err;   /* error code for last stream operation */
  65     int      z_eof;   /* set if end of input file */
  66     FILE     *file;   /* .gz file */
  67     Byte     *inbuf;  /* input buffer */
  68     Byte     *outbuf; /* output buffer */
  69     uLong    crc;     /* crc32 of uncompressed data */
  70     char     *msg;    /* error message */
  71     char     *path;   /* path name for debugging only */
  72     int      transparent; /* 1 if input file is not a .gz file */
  73     char     mode;    /* 'w' or 'r' */
  74     z_off_t  start;   /* start of compressed data in file (header skipped) */
  75     z_off_t  in;      /* bytes into deflate or inflate */
  76     z_off_t  out;     /* bytes out of deflate or inflate */
  77     int      back;    /* one character push-back */
  78     int      last;    /* true if push-back is last character */
  79 } gz_stream;
  80
  81
  82 local gzFile gz_open      OF((const char *path, const char *mode, int  fd));
  83 local int do_flush        OF((gzFile file, int flush));
  84 local int    get_byte     OF((gz_stream *s));
  85 local void   check_header OF((gz_stream *s));
  86 local int    destroy      OF((gz_stream *s));
  87 local void   putLong      OF((FILE *file, uLong x));
  88 local uLong  getLong      OF((gz_stream *s));
  89
  90 /* ===========================================================================
  91      Opens a gzip (.gz) file for reading or writing. The mode parameter
  92    is as in fopen ("rb" or "wb"). The file is given either by file descriptor
  93    or path name (if fd == -1).
  94      gz_open returns NULL if the file could not be opened or if there was
  95    insufficient memory to allocate the (de)compression state; errno
  96    can be checked to distinguish the two cases (if errno is zero, the
  97    zlib error is Z_MEM_ERROR).
  98 */
  99 local gzFile gz_open (path, mode, fd)
 100     const char *path;
 101     const char *mode;
 102     int  fd;
 103 {
 104     int err;
 105     int level = Z_DEFAULT_COMPRESSION; /* compression level */
 106     int strategy = Z_DEFAULT_STRATEGY; /* compression strategy */
 107     char *p = (char*)mode;
 108     gz_stream *s;
 109     char fmode[80]; /* copy of mode, without the compression level */
 110     char *m = fmode;
 111
 112     if (!path || !mode) return Z_NULL;
 113
 114     s = (gz_stream *)ALLOC(sizeof(gz_stream));
 115     if (!s) return Z_NULL;
 116
 117     s->stream.zalloc = (alloc_func)0;
 118     s->stream.zfree = (free_func)0;
 119     s->stream.opaque = (voidpf)0;
 120     s->stream.next_in = s->inbuf = Z_NULL;
 121     s->stream.next_out = s->outbuf = Z_NULL;
 122     s->stream.avail_in = s->stream.avail_out = 0;
 123     s->file = NULL;
 124     s->z_err = Z_OK;
 125     s->z_eof = 0;
 126     s->in = 0;
 127     s->out = 0;
 128     s->back = EOF;
 129     s->crc = crc32(0L, Z_NULL, 0);
 130     s->msg = NULL;
 131     s->transparent = 0;
 132
 133     s->path = (char*)ALLOC(strlen(path)+1);
 134     if (s->path == NULL) {
 135         return destroy(s), (gzFile)Z_NULL;
 136     }
 137     strcpy(s->path, path); /* do this early for debugging */
 138
 139     s->mode = '\0';
 140     do {
 141         if (*p == 'r') s->mode = 'r';
 142         if (*p == 'w' || *p == 'a') s->mode = 'w';
 143         if (*p >= '0' && *p <= '9') {
 144             level = *p - '0';
 145         } else if (*p == 'f') {
 146           strategy = Z_FILTERED;
 147         } else if (*p == 'h') {
 148           strategy = Z_HUFFMAN_ONLY;
 149         } else if (*p == 'R') {
 150           strategy = Z_RLE;
 151         } else {
 152             *m++ = *p; /* copy the mode */
 153         }
 154     } while (*p++ && m != fmode + sizeof(fmode));
 155     if (s->mode == '\0') return destroy(s), (gzFile)Z_NULL;
 156
 157     if (s->mode == 'w') {
 158 #ifdef NO_GZCOMPRESS
 159         err = Z_STREAM_ERROR;
 160 #else
 161         err = deflateInit2(&(s->stream), level,
 162                            Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL, strategy);
 163         /* windowBits is passed < 0 to suppress zlib header */
 164
 165         s->stream.next_out = s->outbuf = (Byte*)ALLOC(Z_BUFSIZE);
 166 #endif
 167         if (err != Z_OK || s->outbuf == Z_NULL) {
 168             return destroy(s), (gzFile)Z_NULL;
 169         }
 170     } else {
 171         s->stream.next_in  = s->inbuf = (Byte*)ALLOC(Z_BUFSIZE);
 172
 173         err = inflateInit2(&(s->stream), -MAX_WBITS);
 174         /* windowBits is passed < 0 to tell that there is no zlib header.
 175          * Note that in this case inflate *requires* an extra "dummy" byte
 176          * after the compressed stream in order to complete decompression and
 177          * return Z_STREAM_END. Here the gzip CRC32 ensures that 4 bytes are
 178          * present after the compressed stream.
 179          */
 180         if (err != Z_OK || s->inbuf == Z_NULL) {
 181             return destroy(s), (gzFile)Z_NULL;
 182         }
 183     }
 184     s->stream.avail_out = Z_BUFSIZE;
 185
 186     errno = 0;
 187     s->file = fd < 0 ? F_OPEN(path, fmode) : (FILE*)fdopen(fd, fmode);
 188
 189     if (s->file == NULL) {
 190         return destroy(s), (gzFile)Z_NULL;
 191     }
 192     if (s->mode == 'w') {
 193         /* Write a very simple .gz header:
 194          */
 195         fprintf(s->file, "%c%c%c%c%c%c%c%c%c%c", gz_magic[0], gz_magic[1],
 196              Z_DEFLATED, 0 /*flags*/, 0,0,0,0 /*time*/, 0 /*xflags*/, OS_CODE);
 197         s->start = 10L;
 198         /* We use 10L instead of ftell(s->file) to because ftell causes an
 199          * fflush on some systems. This version of the library doesn't use
 200          * start anyway in write mode, so this initialization is not
 201          * necessary.
 202          */
 203     } else {
 204         check_header(s); /* skip the .gz header */
 205         s->start = ftell(s->file) - s->stream.avail_in;
 206     }
 207
 208     return (gzFile)s;
 209 }
 210
 211 /* ===========================================================================
 212      Opens a gzip (.gz) file for reading or writing.
 213 */
 214 gzFile ZEXPORT gzopen (path, mode)
 215     const char *path;
 216     const char *mode;
 217 {
 218     return gz_open (path, mode, -1);
 219 }
 220
 221 /* ===========================================================================
 222      Associate a gzFile with the file descriptor fd. fd is not dup'ed here
 223    to mimic the behavio(u)r of fdopen.
 224 */
 225 gzFile ZEXPORT gzdopen (fd, mode)
 226     int fd;
 227     const char *mode;
 228 {
 229     char name[46];      /* allow for up to 128-bit integers */
 230
 231     if (fd < 0) return (gzFile)Z_NULL;
 232     sprintf(name, "<fd:%d>", fd); /* for debugging */
 233
 234     return gz_open (name, mode, fd);
 235 }
 236
 237 /* ===========================================================================
 238  * Update the compression level and strategy
 239  */
 240 int ZEXPORT gzsetparams (file, level, strategy)
 241     gzFile file;
 242     int level;
 243     int strategy;
 244 {
 245     gz_stream *s = (gz_stream*)file;
 246
 247     if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
 248
 249     /* Make room to allow flushing */
 250     if (s->stream.avail_out == 0) {
 251
 252         s->stream.next_out = s->outbuf;
 253         if (fwrite(s->outbuf, 1, Z_BUFSIZE, s->file) != Z_BUFSIZE) {
 254             s->z_err = Z_ERRNO;
 255         }
 256         s->stream.avail_out = Z_BUFSIZE;
 257     }
 258
 259     return deflateParams (&(s->stream), level, strategy);
 260 }
 261
 262 /* ===========================================================================
 263      Read a byte from a gz_stream; update next_in and avail_in. Return EOF
 264    for end of file.
 265    IN assertion: the stream s has been sucessfully opened for reading.
 266 */
 267 local int get_byte(s)
 268     gz_stream *s;
 269 {
 270     if (s->z_eof) return EOF;
 271     if (s->stream.avail_in == 0) {
 272         errno = 0;
 273         s->stream.avail_in = (uInt)fread(s->inbuf, 1, Z_BUFSIZE, s->file);
 274         if (s->stream.avail_in == 0) {
 275             s->z_eof = 1;
 276             if (ferror(s->file)) s->z_err = Z_ERRNO;
 277             return EOF;
 278         }
 279         s->stream.next_in = s->inbuf;
 280     }
 281     s->stream.avail_in--;
 282     return *(s->stream.next_in)++;
 283 }
 284
 285 /* ===========================================================================
 286       Check the gzip header of a gz_stream opened for reading. Set the stream
 287     mode to transparent if the gzip magic header is not present; set s->err
 288     to Z_DATA_ERROR if the magic header is present but the rest of the header
 289     is incorrect.
 290     IN assertion: the stream s has already been created sucessfully;
 291        s->stream.avail_in is zero for the first time, but may be non-zero
 292        for concatenated .gz files.
 293 */
 294 local void check_header(s)
 295     gz_stream *s;
 296 {
 297     int method; /* method byte */
 298     int flags;  /* flags byte */
 299     uInt len;
 300     int c;
 301
 302     /* Assure two bytes in the buffer so we can peek ahead -- handle case
 303        where first byte of header is at the end of the buffer after the last
 304        gzip segment */
 305     len = s->stream.avail_in;
 306     if (len < 2) {
 307         if (len) s->inbuf[0] = s->stream.next_in[0];
 308         errno = 0;
 309         len = (uInt)fread(s->inbuf + len, 1, Z_BUFSIZE >> len, s->file);
 310         if (len == 0 && ferror(s->file)) s->z_err = Z_ERRNO;
 311         s->stream.avail_in += len;
 312         s->stream.next_in = s->inbuf;
 313         if (s->stream.avail_in < 2) {
 314             s->transparent = s->stream.avail_in;
 315             return;
 316         }
 317     }
 318
 319     /* Peek ahead to check the gzip magic header */
 320     if (s->stream.next_in[0] != gz_magic[0] ||
 321         s->stream.next_in[1] != gz_magic[1]) {
 322         s->transparent = 1;
 323         return;
 324     }
 325     s->stream.avail_in -= 2;
 326     s->stream.next_in += 2;
 327
 328     /* Check the rest of the gzip header */
 329     method = get_byte(s);
 330     flags = get_byte(s);
 331     if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
 332         s->z_err = Z_DATA_ERROR;
 333         return;
 334     }
 335
 336     /* Discard time, xflags and OS code: */
 337     for (len = 0; len < 6; len++) (void)get_byte(s);
 338
 339     if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
 340         len  =  (uInt)get_byte(s);
 341         len += ((uInt)get_byte(s))<<8;
 342         /* len is garbage if EOF but the loop below will quit anyway */
 343         while (len-- != 0 && get_byte(s) != EOF) ;
 344     }
 345     if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
 346         while ((c = get_byte(s)) != 0 && c != EOF) ;
 347     }
 348     if ((flags & COMMENT) != 0) {   /* skip the .gz file comment */
 349         while ((c = get_byte(s)) != 0 && c != EOF) ;
 350     }
 351     if ((flags & HEAD_CRC) != 0) {  /* skip the header crc */
 352         for (len = 0; len < 2; len++) (void)get_byte(s);
 353     }
 354     s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK;
 355 }
 356
 357  /* ===========================================================================
 358  * Cleanup then free the given gz_stream. Return a zlib error code.
 359    Try freeing in the reverse order of allocations.
 360  */
 361 local int destroy (s)
 362     gz_stream *s;
 363 {
 364     int err = Z_OK;
 365
 366     if (!s) return Z_STREAM_ERROR;
 367
 368     TRYFREE(s->msg);
 369
 370     if (s->stream.state != NULL) {
 371         if (s->mode == 'w') {
 372 #ifdef NO_GZCOMPRESS
 373             err = Z_STREAM_ERROR;
 374 #else
 375             err = deflateEnd(&(s->stream));
 376 #endif
 377         } else if (s->mode == 'r') {
 378             err = inflateEnd(&(s->stream));
 379         }
 380     }
 381     if (s->file != NULL && fclose(s->file)) {
 382 #ifdef ESPIPE
 383         if (errno != ESPIPE) /* fclose is broken for pipes in HP/UX */
 384 #endif
 385             err = Z_ERRNO;
 386     }
 387     if (s->z_err < 0) err = s->z_err;
 388
 389     TRYFREE(s->inbuf);
 390     TRYFREE(s->outbuf);
 391     TRYFREE(s->path);
 392     TRYFREE(s);
 393     return err;
 394 }
 395
 396 /* ===========================================================================
 397      Reads the given number of uncompressed bytes from the compressed file.
 398    gzread returns the number of bytes actually read (0 for end of file).
 399 */
 400 int ZEXPORT gzread (file, buf, len)
 401     gzFile file;
 402     voidp buf;
 403     unsigned len;
 404 {
 405     gz_stream *s = (gz_stream*)file;
 406     Bytef *start = (Bytef*)buf; /* starting point for crc computation */
 407     Byte  *next_out; /* == stream.next_out but not forced far (for MSDOS) */
 408
 409     if (s == NULL || s->mode != 'r') return Z_STREAM_ERROR;
 410
 411     if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO) return -1;
 412     if (s->z_err == Z_STREAM_END) return 0;  /* EOF */
 413
 414     next_out = (Byte*)buf;
 415     s->stream.next_out = (Bytef*)buf;
 416     s->stream.avail_out = len;
 417
 418     if (s->stream.avail_out && s->back != EOF) {
 419         *next_out++ = s->back;
 420         s->stream.next_out++;
 421         s->stream.avail_out--;
 422         s->back = EOF;
 423         s->out++;
 424         start++;
 425         if (s->last) {
 426             s->z_err = Z_STREAM_END;
 427             return 1;
 428         }
 429     }
 430
 431     while (s->stream.avail_out != 0) {
 432
 433         if (s->transparent) {
 434             /* Copy first the lookahead bytes: */
 435             uInt n = s->stream.avail_in;
 436             if (n > s->stream.avail_out) n = s->stream.avail_out;
 437             if (n > 0) {
 438                 zmemcpy(s->stream.next_out, s->stream.next_in, n);
 439                 next_out += n;
 440                 s->stream.next_out = next_out;
 441                 s->stream.next_in   += n;
 442                 s->stream.avail_out -= n;
 443                 s->stream.avail_in  -= n;
 444             }
 445             if (s->stream.avail_out > 0) {
 446                 s->stream.avail_out -=
 447                     (uInt)fread(next_out, 1, s->stream.avail_out, s->file);
 448             }
 449             len -= s->stream.avail_out;
 450             s->in  += len;
 451             s->out += len;
 452             if (len == 0) s->z_eof = 1;
 453             return (int)len;
 454         }
 455         if (s->stream.avail_in == 0 && !s->z_eof) {
 456
 457             errno = 0;
 458             s->stream.avail_in = (uInt)fread(s->inbuf, 1, Z_BUFSIZE, s->file);
 459             if (s->stream.avail_in == 0) {
 460                 s->z_eof = 1;
 461                 if (ferror(s->file)) {
 462                     s->z_err = Z_ERRNO;
 463                     break;
 464                 }
 465             }
 466             s->stream.next_in = s->inbuf;
 467         }
 468         s->in += s->stream.avail_in;
 469         s->out += s->stream.avail_out;
 470         s->z_err = inflate(&(s->stream), Z_NO_FLUSH);
 471         s->in -= s->stream.avail_in;
 472         s->out -= s->stream.avail_out;
 473
 474         if (s->z_err == Z_STREAM_END) {
 475             /* Check CRC and original size */
 476             s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
 477             start = s->stream.next_out;
 478
 479             if (getLong(s) != s->crc) {
 480                 s->z_err = Z_DATA_ERROR;
 481             } else {
 482                 (void)getLong(s);
 483                 /* The uncompressed length returned by above getlong() may be
 484                  * different from s->out in case of concatenated .gz files.
 485                  * Check for such files:
 486                  */
 487                 check_header(s);
 488                 if (s->z_err == Z_OK) {
 489                     inflateReset(&(s->stream));
 490                     s->crc = crc32(0L, Z_NULL, 0);
 491                 }
 492             }
 493         }
 494         if (s->z_err != Z_OK || s->z_eof) break;
 495     }
 496     s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
 497
 498     if (len == s->stream.avail_out &&
 499         (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO))
 500         return -1;
 501     return (int)(len - s->stream.avail_out);
 502 }
 503
 504
 505 /* ===========================================================================
 506       Reads one byte from the compressed file. gzgetc returns this byte
 507    or -1 in case of end of file or error.
 508 */
 509 int ZEXPORT gzgetc(file)
 510     gzFile file;
 511 {
 512     unsigned char c;
 513
 514     return gzread(file, &c, 1) == 1 ? c : -1;
 515 }
 516
 517
 518 /* ===========================================================================
 519       Push one byte back onto the stream.
 520 */
 521 int ZEXPORT gzungetc(c, file)
 522     int c;
 523     gzFile file;
 524 {
 525     gz_stream *s = (gz_stream*)file;
 526
 527     if (s == NULL || s->mode != 'r' || c == EOF || s->back != EOF) return EOF;
 528     s->back = c;
 529     s->out--;
 530     s->last = (s->z_err == Z_STREAM_END);
 531     if (s->last) s->z_err = Z_OK;
 532     s->z_eof = 0;
 533     return c;
 534 }
 535
 536
 537 /* ===========================================================================
 538       Reads bytes from the compressed file until len-1 characters are
 539    read, or a newline character is read and transferred to buf, or an
 540    end-of-file condition is encountered.  The string is then terminated
 541    with a null character.
 542       gzgets returns buf, or Z_NULL in case of error.
 543
 544       The current implementation is not optimized at all.
 545 */
 546 char * ZEXPORT gzgets(file, buf, len)
 547     gzFile file;
 548     char *buf;
 549     int len;
 550 {
 551     char *b = buf;
 552     if (buf == Z_NULL || len <= 0) return Z_NULL;
 553
 554     while (--len > 0 && gzread(file, buf, 1) == 1 && *buf++ != '\n') ;
 555     *buf = '\0';
 556     return b == buf && len > 0 ? Z_NULL : b;
 557 }
 558
 559
 560 #ifndef NO_GZCOMPRESS
 561 /* ===========================================================================
 562      Writes the given number of uncompressed bytes into the compressed file.
 563    gzwrite returns the number of bytes actually written (0 in case of error).
 564 */
 565 int ZEXPORT gzwrite (file, buf, len)
 566     gzFile file;
 567     voidpc buf;
 568     unsigned len;
 569 {
 570     gz_stream *s = (gz_stream*)file;
 571
 572     if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
 573
 574     s->stream.next_in = (Bytef*)buf;
 575     s->stream.avail_in = len;
 576
 577     while (s->stream.avail_in != 0) {
 578
 579         if (s->stream.avail_out == 0) {
 580
 581             s->stream.next_out = s->outbuf;
 582             if (fwrite(s->outbuf, 1, Z_BUFSIZE, s->file) != Z_BUFSIZE) {
 583                 s->z_err = Z_ERRNO;
 584                 break;
 585             }
 586             s->stream.avail_out = Z_BUFSIZE;
 587         }
 588         s->in += s->stream.avail_in;
 589         s->out += s->stream.avail_out;
 590         s->z_err = deflate(&(s->stream), Z_NO_FLUSH);
 591         s->in -= s->stream.avail_in;
 592         s->out -= s->stream.avail_out;
 593         if (s->z_err != Z_OK) break;
 594     }
 595     s->crc = crc32(s->crc, (const Bytef *)buf, len);
 596
 597     return (int)(len - s->stream.avail_in);
 598 }
 599
 600
 601 /* ===========================================================================
 602      Converts, formats, and writes the args to the compressed file under
 603    control of the format string, as in fprintf. gzprintf returns the number of
 604    uncompressed bytes actually written (0 in case of error).
 605 */
 606 #ifdef STDC
 607 #include <stdarg.h>
 608
 609 int ZEXPORTVA gzprintf (gzFile file, const char *format, /* args */ ...)
 610 {
 611     char buf[Z_PRINTF_BUFSIZE];
 612     va_list va;
 613     int len;
 614
 615     buf[sizeof(buf) - 1] = 0;
 616     va_start(va, format);
 617 #ifdef NO_vsnprintf
 618 #  ifdef HAS_vsprintf_void
 619     (void)vsprintf(buf, format, va);
 620     va_end(va);
 621     for (len = 0; len < sizeof(buf); len++)
 622         if (buf[len] == 0) break;
 623 #  else
 624     len = vsprintf(buf, format, va);
 625     va_end(va);
 626 #  endif
 627 #else
 628 #  ifdef HAS_vsnprintf_void
 629     (void)vsnprintf(buf, sizeof(buf), format, va);
 630     va_end(va);
 631     len = strlen(buf);
 632 #  else
 633     len = vsnprintf(buf, sizeof(buf), format, va);
 634     va_end(va);
 635 #  endif
 636 #endif
 637     if (len <= 0 || len >= (int)sizeof(buf) || buf[sizeof(buf) - 1] != 0)
 638         return 0;
 639     return gzwrite(file, buf, (unsigned)len);
 640 }
 641 #else /* not ANSI C */
 642
 643 int ZEXPORTVA gzprintf (file, format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
 644                        a11, a12, a13, a14, a15, a16, a17, a18, a19, a20)
 645     gzFile file;
 646     const char *format;
 647     int a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
 648         a11, a12, a13, a14, a15, a16, a17, a18, a19, a20;
 649 {
 650     char buf[Z_PRINTF_BUFSIZE];
 651     int len;
 652
 653     buf[sizeof(buf) - 1] = 0;
 654 #ifdef NO_snprintf
 655 #  ifdef HAS_sprintf_void
 656     sprintf(buf, format, a1, a2, a3, a4, a5, a6, a7, a8,
 657             a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
 658     for (len = 0; len < sizeof(buf); len++)
 659         if (buf[len] == 0) break;
 660 #  else
 661     len = sprintf(buf, format, a1, a2, a3, a4, a5, a6, a7, a8,
 662                 a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
 663 #  endif
 664 #else
 665 #  ifdef HAS_snprintf_void
 666     snprintf(buf, sizeof(buf), format, a1, a2, a3, a4, a5, a6, a7, a8,
 667              a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
 668     len = strlen(buf);
 669 #  else
 670     len = snprintf(buf, sizeof(buf), format, a1, a2, a3, a4, a5, a6, a7, a8,
 671                  a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
 672 #  endif
 673 #endif
 674     if (len <= 0 || len >= sizeof(buf) || buf[sizeof(buf) - 1] != 0)
 675         return 0;
 676     return gzwrite(file, buf, len);
 677 }
 678 #endif
 679
 680 /* ===========================================================================
 681       Writes c, converted to an unsigned char, into the compressed file.
 682    gzputc returns the value that was written, or -1 in case of error.
 683 */
 684 int ZEXPORT gzputc(file, c)
 685     gzFile file;
 686     int c;
 687 {
 688     unsigned char cc = (unsigned char) c; /* required for big endian systems */
 689
 690     return gzwrite(file, &cc, 1) == 1 ? (int)cc : -1;
 691 }
 692
 693
 694 /* ===========================================================================
 695       Writes the given null-terminated string to the compressed file, excluding
 696    the terminating null character.
 697       gzputs returns the number of characters written, or -1 in case of error.
 698 */
 699 int ZEXPORT gzputs(file, s)
 700     gzFile file;
 701     const char *s;
 702 {
 703     return gzwrite(file, (char*)s, (unsigned)strlen(s));
 704 }
 705
 706
 707 /* ===========================================================================
 708      Flushes all pending output into the compressed file. The parameter
 709    flush is as in the deflate() function.
 710 */
 711 local int do_flush (file, flush)
 712     gzFile file;
 713     int flush;
 714 {
 715     uInt len;
 716     int done = 0;
 717     gz_stream *s = (gz_stream*)file;
 718
 719     if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
 720
 721     s->stream.avail_in = 0; /* should be zero already anyway */
 722
 723     for (;;) {
 724         len = Z_BUFSIZE - s->stream.avail_out;
 725
 726         if (len != 0) {
 727             if ((uInt)fwrite(s->outbuf, 1, len, s->file) != len) {
 728                 s->z_err = Z_ERRNO;
 729                 return Z_ERRNO;
 730             }
 731             s->stream.next_out = s->outbuf;
 732             s->stream.avail_out = Z_BUFSIZE;
 733         }
 734         if (done) break;
 735         s->out += s->stream.avail_out;
 736         s->z_err = deflate(&(s->stream), flush);
 737         s->out -= s->stream.avail_out;
 738
 739         /* Ignore the second of two consecutive flushes: */
 740         if (len == 0 && s->z_err == Z_BUF_ERROR) s->z_err = Z_OK;
 741
 742         /* deflate has finished flushing only when it hasn't used up
 743          * all the available space in the output buffer:
 744          */
 745         done = (s->stream.avail_out != 0 || s->z_err == Z_STREAM_END);
 746
 747         if (s->z_err != Z_OK && s->z_err != Z_STREAM_END) break;
 748     }
 749     return  s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
 750 }
 751
 752 int ZEXPORT gzflush (file, flush)
 753      gzFile file;
 754      int flush;
 755 {
 756     gz_stream *s = (gz_stream*)file;
 757     int err = do_flush (file, flush);
 758
 759     if (err) return err;
 760     fflush(s->file);
 761     return  s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
 762 }
 763 #endif /* NO_GZCOMPRESS */
 764
 765 /* ===========================================================================
 766       Sets the starting position for the next gzread or gzwrite on the given
 767    compressed file. The offset represents a number of bytes in the
 768       gzseek returns the resulting offset location as measured in bytes from
 769    the beginning of the uncompressed stream, or -1 in case of error.
 770       SEEK_END is not implemented, returns error.
 771       In this version of the library, gzseek can be extremely slow.
 772 */
 773 z_off_t ZEXPORT gzseek (file, offset, whence)
 774     gzFile file;
 775     z_off_t offset;
 776     int whence;
 777 {
 778     gz_stream *s = (gz_stream*)file;
 779
 780     if (s == NULL || whence == SEEK_END ||
 781         s->z_err == Z_ERRNO || s->z_err == Z_DATA_ERROR) {
 782         return -1L;
 783     }
 784
 785     if (s->mode == 'w') {
 786 #ifdef NO_GZCOMPRESS
 787         return -1L;
 788 #else
 789         if (whence == SEEK_SET) {
 790             offset -= s->in;
 791         }
 792         if (offset < 0) return -1L;
 793
 794         /* At this point, offset is the number of zero bytes to write. */
 795         if (s->inbuf == Z_NULL) {
 796             s->inbuf = (Byte*)ALLOC(Z_BUFSIZE); /* for seeking */
 797             if (s->inbuf == Z_NULL) return -1L;
 798             zmemzero(s->inbuf, Z_BUFSIZE);
 799         }
 800         while (offset > 0)  {
 801             uInt size = Z_BUFSIZE;
 802             if (offset < Z_BUFSIZE) size = (uInt)offset;
 803
 804             size = gzwrite(file, s->inbuf, size);
 805             if (size == 0) return -1L;
 806
 807             offset -= size;
 808         }
 809         return s->in;
 810 #endif
 811     }
 812     /* Rest of function is for reading only */
 813
 814     /* compute absolute position */
 815     if (whence == SEEK_CUR) {
 816         offset += s->out;
 817     }
 818     if (offset < 0) return -1L;
 819
 820     if (s->transparent) {
 821         /* map to fseek */
 822         s->back = EOF;
 823         s->stream.avail_in = 0;
 824         s->stream.next_in = s->inbuf;
 825         if (fseek(s->file, offset, SEEK_SET) < 0) return -1L;
 826
 827         s->in = s->out = offset;
 828         return offset;
 829     }
 830
 831     /* For a negative seek, rewind and use positive seek */
 832     if (offset >= s->out) {
 833         offset -= s->out;
 834     } else if (gzrewind(file) < 0) {
 835         return -1L;
 836     }
 837     /* offset is now the number of bytes to skip. */
 838
 839     if (offset != 0 && s->outbuf == Z_NULL) {
 840         s->outbuf = (Byte*)ALLOC(Z_BUFSIZE);
 841         if (s->outbuf == Z_NULL) return -1L;
 842     }
 843     if (offset && s->back != EOF) {
 844         s->back = EOF;
 845         s->out++;
 846         offset--;
 847         if (s->last) s->z_err = Z_STREAM_END;
 848     }
 849     while (offset > 0)  {
 850         int size = Z_BUFSIZE;
 851         if (offset < Z_BUFSIZE) size = (int)offset;
 852
 853         size = gzread(file, s->outbuf, (uInt)size);
 854         if (size <= 0) return -1L;
 855         offset -= size;
 856     }
 857     return s->out;
 858 }
 859
 860 /* ===========================================================================
 861      Rewinds input file.
 862 */
 863 int ZEXPORT gzrewind (file)
 864     gzFile file;
 865 {
 866     gz_stream *s = (gz_stream*)file;
 867
 868     if (s == NULL || s->mode != 'r') return -1;
 869
 870     s->z_err = Z_OK;
 871     s->z_eof = 0;
 872     s->back = EOF;
 873     s->stream.avail_in = 0;
 874     s->stream.next_in = s->inbuf;
 875     s->crc = crc32(0L, Z_NULL, 0);
 876     if (!s->transparent) (void)inflateReset(&s->stream);
 877     s->in = 0;
 878     s->out = 0;
 879     return fseek(s->file, s->start, SEEK_SET);
 880 }
 881
 882 /* ===========================================================================
 883      Returns the starting position for the next gzread or gzwrite on the
 884    given compressed file. This position represents a number of bytes in the
 885    uncompressed data stream.
 886 */
 887 z_off_t ZEXPORT gztell (file)
 888     gzFile file;
 889 {
 890     return gzseek(file, 0L, SEEK_CUR);
 891 }
 892
 893 /* ===========================================================================
 894      Returns 1 when EOF has previously been detected reading the given
 895    input stream, otherwise zero.
 896 */
 897 int ZEXPORT gzeof (file)
 898     gzFile file;
 899 {
 900     gz_stream *s = (gz_stream*)file;
 901
 902     /* With concatenated compressed files that can have embedded
 903      * crc trailers, z_eof is no longer the only/best indicator of EOF
 904      * on a gz_stream. Handle end-of-stream error explicitly here.
 905      */
 906     if (s == NULL || s->mode != 'r') return 0;
 907     if (s->z_eof) return 1;
 908     return s->z_err == Z_STREAM_END;
 909 }
 910
 911 /* ===========================================================================
 912      Returns 1 if reading and doing so transparently, otherwise zero.
 913 */
 914 int ZEXPORT gzdirect (file)
 915     gzFile file;
 916 {
 917     gz_stream *s = (gz_stream*)file;
 918
 919     if (s == NULL || s->mode != 'r') return 0;
 920     return s->transparent;
 921 }
 922
 923 /* ===========================================================================
 924    Outputs a long in LSB order to the given file
 925 */
 926 local void putLong (file, x)
 927     FILE *file;
 928     uLong x;
 929 {
 930     int n;
 931     for (n = 0; n < 4; n++) {
 932         fputc((int)(x & 0xff), file);
 933         x >>= 8;
 934     }
 935 }
 936
 937 /* ===========================================================================
 938    Reads a long in LSB order from the given gz_stream. Sets z_err in case
 939    of error.
 940 */
 941 local uLong getLong (s)
 942     gz_stream *s;
 943 {
 944     uLong x = (uLong)get_byte(s);
 945     int c;
 946
 947     x += ((uLong)get_byte(s))<<8;
 948     x += ((uLong)get_byte(s))<<16;
 949     c = get_byte(s);
 950     if (c == EOF) s->z_err = Z_DATA_ERROR;
 951     x += ((uLong)c)<<24;
 952     return x;
 953 }
 954
 955 /* ===========================================================================
 956      Flushes all pending output if necessary, closes the compressed file
 957    and deallocates all the (de)compression state.
 958 */
 959 int ZEXPORT gzclose (file)
 960     gzFile file;
 961 {
 962     gz_stream *s = (gz_stream*)file;
 963
 964     if (s == NULL) return Z_STREAM_ERROR;
 965
 966     if (s->mode == 'w') {
 967 #ifdef NO_GZCOMPRESS
 968         return Z_STREAM_ERROR;
 969 #else
 970         if (do_flush (file, Z_FINISH) != Z_OK)
 971             return destroy((gz_stream*)file);
 972
 973         putLong (s->file, s->crc);
 974         putLong (s->file, (uLong)(s->in & 0xffffffff));
 975 #endif
 976     }
 977     return destroy((gz_stream*)file);
 978 }
 979
 980 #ifdef STDC
 981 #  define zstrerror(errnum) strerror(errnum)
 982 #else
 983 #  define zstrerror(errnum) ""
 984 #endif
 985
 986 /* ===========================================================================
 987      Returns the error message for the last error which occurred on the
 988    given compressed file. errnum is set to zlib error number. If an
 989    error occurred in the file system and not in the compression library,
 990    errnum is set to Z_ERRNO and the application may consult errno
 991    to get the exact error code.
 992 */
 993 const char * ZEXPORT gzerror (file, errnum)
 994     gzFile file;
 995     int *errnum;
 996 {
 997     char *m;
 998     gz_stream *s = (gz_stream*)file;
 999
1000     if (s == NULL) {
1001         *errnum = Z_STREAM_ERROR;
1002         return (const char*)ERR_MSG(Z_STREAM_ERROR);
1003     }
1004     *errnum = s->z_err;
1005     if (*errnum == Z_OK) return (const char*)"";
1006
1007     m = (char*)(*errnum == Z_ERRNO ? zstrerror(errno) : s->stream.msg);
1008
1009     if (m == NULL || *m == '\0') m = (char*)ERR_MSG(s->z_err);
1010
1011     TRYFREE(s->msg);
1012     s->msg = (char*)ALLOC(strlen(s->path) + strlen(m) + 3);
1013     if (s->msg == Z_NULL) return (const char*)ERR_MSG(Z_MEM_ERROR);
1014     strcpy(s->msg, s->path);
1015     strcat(s->msg, ": ");
1016     strcat(s->msg, m);
1017     return (const char*)s->msg;
1018 }
1019
1020 /* ===========================================================================
1021      Clear the error and end-of-file flags, and do the same for the real file.
1022 */
1023 void ZEXPORT gzclearerr (file)
1024     gzFile file;
1025 {
1026     gz_stream *s = (gz_stream*)file;
1027
1028     if (s == NULL) return;
1029     if (s->z_err != Z_STREAM_END) s->z_err = Z_OK;
1030     s->z_eof = 0;
1031     clearerr(s->file);
1032 }