source: rtems/cpukit/zlib/gzio.c @ 94a2ecc

4.11
Last change on this file since 94a2ecc was 8198f69, checked in by Ralf Corsepius <ralf.corsepius@…>, on Mar 18, 2011 at 10:10:55 AM

Import zlib-1.2.3

  • Property mode set to 100644
File size: 30.4 KB
Line 
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
19struct 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
39extern voidp  malloc OF((uInt size));
40extern void   free   OF((voidpf ptr));
41#endif
42
43#define ALLOC(size) malloc(size)
44#define TRYFREE(p) {if (p) free(p);}
45
46static int const gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
47
48/* gzip flag byte */
49#define ASCII_FLAG   0x01 /* bit 0 set: file probably ascii text */
50#define HEAD_CRC     0x02 /* bit 1 set: header CRC present */
51#define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
52#define ORIG_NAME    0x08 /* bit 3 set: original file name present */
53#define COMMENT      0x10 /* bit 4 set: file comment present */
54#define RESERVED     0xE0 /* bits 5..7: reserved */
55
56typedef struct gz_stream {
57    z_stream stream;
58    int      z_err;   /* error code for last stream operation */
59    int      z_eof;   /* set if end of input file */
60    FILE     *file;   /* .gz file */
61    Byte     *inbuf;  /* input buffer */
62    Byte     *outbuf; /* output buffer */
63    uLong    crc;     /* crc32 of uncompressed data */
64    char     *msg;    /* error message */
65    char     *path;   /* path name for debugging only */
66    int      transparent; /* 1 if input file is not a .gz file */
67    char     mode;    /* 'w' or 'r' */
68    z_off_t  start;   /* start of compressed data in file (header skipped) */
69    z_off_t  in;      /* bytes into deflate or inflate */
70    z_off_t  out;     /* bytes out of deflate or inflate */
71    int      back;    /* one character push-back */
72    int      last;    /* true if push-back is last character */
73} gz_stream;
74
75
76local gzFile gz_open      OF((const char *path, const char *mode, int  fd));
77local int do_flush        OF((gzFile file, int flush));
78local int    get_byte     OF((gz_stream *s));
79local void   check_header OF((gz_stream *s));
80local int    destroy      OF((gz_stream *s));
81local void   putLong      OF((FILE *file, uLong x));
82local uLong  getLong      OF((gz_stream *s));
83
84/* ===========================================================================
85     Opens a gzip (.gz) file for reading or writing. The mode parameter
86   is as in fopen ("rb" or "wb"). The file is given either by file descriptor
87   or path name (if fd == -1).
88     gz_open returns NULL if the file could not be opened or if there was
89   insufficient memory to allocate the (de)compression state; errno
90   can be checked to distinguish the two cases (if errno is zero, the
91   zlib error is Z_MEM_ERROR).
92*/
93local gzFile gz_open (path, mode, fd)
94    const char *path;
95    const char *mode;
96    int  fd;
97{
98    int err;
99    int level = Z_DEFAULT_COMPRESSION; /* compression level */
100    int strategy = Z_DEFAULT_STRATEGY; /* compression strategy */
101    char *p = (char*)mode;
102    gz_stream *s;
103    char fmode[80]; /* copy of mode, without the compression level */
104    char *m = fmode;
105
106    if (!path || !mode) return Z_NULL;
107
108    s = (gz_stream *)ALLOC(sizeof(gz_stream));
109    if (!s) return Z_NULL;
110
111    s->stream.zalloc = (alloc_func)0;
112    s->stream.zfree = (free_func)0;
113    s->stream.opaque = (voidpf)0;
114    s->stream.next_in = s->inbuf = Z_NULL;
115    s->stream.next_out = s->outbuf = Z_NULL;
116    s->stream.avail_in = s->stream.avail_out = 0;
117    s->file = NULL;
118    s->z_err = Z_OK;
119    s->z_eof = 0;
120    s->in = 0;
121    s->out = 0;
122    s->back = EOF;
123    s->crc = crc32(0L, Z_NULL, 0);
124    s->msg = NULL;
125    s->transparent = 0;
126
127    s->path = (char*)ALLOC(strlen(path)+1);
128    if (s->path == NULL) {
129        return destroy(s), (gzFile)Z_NULL;
130    }
131    strcpy(s->path, path); /* do this early for debugging */
132
133    s->mode = '\0';
134    do {
135        if (*p == 'r') s->mode = 'r';
136        if (*p == 'w' || *p == 'a') s->mode = 'w';
137        if (*p >= '0' && *p <= '9') {
138            level = *p - '0';
139        } else if (*p == 'f') {
140          strategy = Z_FILTERED;
141        } else if (*p == 'h') {
142          strategy = Z_HUFFMAN_ONLY;
143        } else if (*p == 'R') {
144          strategy = Z_RLE;
145        } else {
146            *m++ = *p; /* copy the mode */
147        }
148    } while (*p++ && m != fmode + sizeof(fmode));
149    if (s->mode == '\0') return destroy(s), (gzFile)Z_NULL;
150
151    if (s->mode == 'w') {
152#ifdef NO_GZCOMPRESS
153        err = Z_STREAM_ERROR;
154#else
155        err = deflateInit2(&(s->stream), level,
156                           Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL, strategy);
157        /* windowBits is passed < 0 to suppress zlib header */
158
159        s->stream.next_out = s->outbuf = (Byte*)ALLOC(Z_BUFSIZE);
160#endif
161        if (err != Z_OK || s->outbuf == Z_NULL) {
162            return destroy(s), (gzFile)Z_NULL;
163        }
164    } else {
165        s->stream.next_in  = s->inbuf = (Byte*)ALLOC(Z_BUFSIZE);
166
167        err = inflateInit2(&(s->stream), -MAX_WBITS);
168        /* windowBits is passed < 0 to tell that there is no zlib header.
169         * Note that in this case inflate *requires* an extra "dummy" byte
170         * after the compressed stream in order to complete decompression and
171         * return Z_STREAM_END. Here the gzip CRC32 ensures that 4 bytes are
172         * present after the compressed stream.
173         */
174        if (err != Z_OK || s->inbuf == Z_NULL) {
175            return destroy(s), (gzFile)Z_NULL;
176        }
177    }
178    s->stream.avail_out = Z_BUFSIZE;
179
180    errno = 0;
181    s->file = fd < 0 ? F_OPEN(path, fmode) : (FILE*)fdopen(fd, fmode);
182
183    if (s->file == NULL) {
184        return destroy(s), (gzFile)Z_NULL;
185    }
186    if (s->mode == 'w') {
187        /* Write a very simple .gz header:
188         */
189        fprintf(s->file, "%c%c%c%c%c%c%c%c%c%c", gz_magic[0], gz_magic[1],
190             Z_DEFLATED, 0 /*flags*/, 0,0,0,0 /*time*/, 0 /*xflags*/, OS_CODE);
191        s->start = 10L;
192        /* We use 10L instead of ftell(s->file) to because ftell causes an
193         * fflush on some systems. This version of the library doesn't use
194         * start anyway in write mode, so this initialization is not
195         * necessary.
196         */
197    } else {
198        check_header(s); /* skip the .gz header */
199        s->start = ftell(s->file) - s->stream.avail_in;
200    }
201
202    return (gzFile)s;
203}
204
205/* ===========================================================================
206     Opens a gzip (.gz) file for reading or writing.
207*/
208gzFile ZEXPORT gzopen (path, mode)
209    const char *path;
210    const char *mode;
211{
212    return gz_open (path, mode, -1);
213}
214
215/* ===========================================================================
216     Associate a gzFile with the file descriptor fd. fd is not dup'ed here
217   to mimic the behavio(u)r of fdopen.
218*/
219gzFile ZEXPORT gzdopen (fd, mode)
220    int fd;
221    const char *mode;
222{
223    char name[46];      /* allow for up to 128-bit integers */
224
225    if (fd < 0) return (gzFile)Z_NULL;
226    sprintf(name, "<fd:%d>", fd); /* for debugging */
227
228    return gz_open (name, mode, fd);
229}
230
231/* ===========================================================================
232 * Update the compression level and strategy
233 */
234int ZEXPORT gzsetparams (file, level, strategy)
235    gzFile file;
236    int level;
237    int strategy;
238{
239    gz_stream *s = (gz_stream*)file;
240
241    if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
242
243    /* Make room to allow flushing */
244    if (s->stream.avail_out == 0) {
245
246        s->stream.next_out = s->outbuf;
247        if (fwrite(s->outbuf, 1, Z_BUFSIZE, s->file) != Z_BUFSIZE) {
248            s->z_err = Z_ERRNO;
249        }
250        s->stream.avail_out = Z_BUFSIZE;
251    }
252
253    return deflateParams (&(s->stream), level, strategy);
254}
255
256/* ===========================================================================
257     Read a byte from a gz_stream; update next_in and avail_in. Return EOF
258   for end of file.
259   IN assertion: the stream s has been sucessfully opened for reading.
260*/
261local int get_byte(s)
262    gz_stream *s;
263{
264    if (s->z_eof) return EOF;
265    if (s->stream.avail_in == 0) {
266        errno = 0;
267        s->stream.avail_in = (uInt)fread(s->inbuf, 1, Z_BUFSIZE, s->file);
268        if (s->stream.avail_in == 0) {
269            s->z_eof = 1;
270            if (ferror(s->file)) s->z_err = Z_ERRNO;
271            return EOF;
272        }
273        s->stream.next_in = s->inbuf;
274    }
275    s->stream.avail_in--;
276    return *(s->stream.next_in)++;
277}
278
279/* ===========================================================================
280      Check the gzip header of a gz_stream opened for reading. Set the stream
281    mode to transparent if the gzip magic header is not present; set s->err
282    to Z_DATA_ERROR if the magic header is present but the rest of the header
283    is incorrect.
284    IN assertion: the stream s has already been created sucessfully;
285       s->stream.avail_in is zero for the first time, but may be non-zero
286       for concatenated .gz files.
287*/
288local void check_header(s)
289    gz_stream *s;
290{
291    int method; /* method byte */
292    int flags;  /* flags byte */
293    uInt len;
294    int c;
295
296    /* Assure two bytes in the buffer so we can peek ahead -- handle case
297       where first byte of header is at the end of the buffer after the last
298       gzip segment */
299    len = s->stream.avail_in;
300    if (len < 2) {
301        if (len) s->inbuf[0] = s->stream.next_in[0];
302        errno = 0;
303        len = (uInt)fread(s->inbuf + len, 1, Z_BUFSIZE >> len, s->file);
304        if (len == 0 && ferror(s->file)) s->z_err = Z_ERRNO;
305        s->stream.avail_in += len;
306        s->stream.next_in = s->inbuf;
307        if (s->stream.avail_in < 2) {
308            s->transparent = s->stream.avail_in;
309            return;
310        }
311    }
312
313    /* Peek ahead to check the gzip magic header */
314    if (s->stream.next_in[0] != gz_magic[0] ||
315        s->stream.next_in[1] != gz_magic[1]) {
316        s->transparent = 1;
317        return;
318    }
319    s->stream.avail_in -= 2;
320    s->stream.next_in += 2;
321
322    /* Check the rest of the gzip header */
323    method = get_byte(s);
324    flags = get_byte(s);
325    if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
326        s->z_err = Z_DATA_ERROR;
327        return;
328    }
329
330    /* Discard time, xflags and OS code: */
331    for (len = 0; len < 6; len++) (void)get_byte(s);
332
333    if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
334        len  =  (uInt)get_byte(s);
335        len += ((uInt)get_byte(s))<<8;
336        /* len is garbage if EOF but the loop below will quit anyway */
337        while (len-- != 0 && get_byte(s) != EOF) ;
338    }
339    if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
340        while ((c = get_byte(s)) != 0 && c != EOF) ;
341    }
342    if ((flags & COMMENT) != 0) {   /* skip the .gz file comment */
343        while ((c = get_byte(s)) != 0 && c != EOF) ;
344    }
345    if ((flags & HEAD_CRC) != 0) {  /* skip the header crc */
346        for (len = 0; len < 2; len++) (void)get_byte(s);
347    }
348    s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK;
349}
350
351 /* ===========================================================================
352 * Cleanup then free the given gz_stream. Return a zlib error code.
353   Try freeing in the reverse order of allocations.
354 */
355local int destroy (s)
356    gz_stream *s;
357{
358    int err = Z_OK;
359
360    if (!s) return Z_STREAM_ERROR;
361
362    TRYFREE(s->msg);
363
364    if (s->stream.state != NULL) {
365        if (s->mode == 'w') {
366#ifdef NO_GZCOMPRESS
367            err = Z_STREAM_ERROR;
368#else
369            err = deflateEnd(&(s->stream));
370#endif
371        } else if (s->mode == 'r') {
372            err = inflateEnd(&(s->stream));
373        }
374    }
375    if (s->file != NULL && fclose(s->file)) {
376#ifdef ESPIPE
377        if (errno != ESPIPE) /* fclose is broken for pipes in HP/UX */
378#endif
379            err = Z_ERRNO;
380    }
381    if (s->z_err < 0) err = s->z_err;
382
383    TRYFREE(s->inbuf);
384    TRYFREE(s->outbuf);
385    TRYFREE(s->path);
386    TRYFREE(s);
387    return err;
388}
389
390/* ===========================================================================
391     Reads the given number of uncompressed bytes from the compressed file.
392   gzread returns the number of bytes actually read (0 for end of file).
393*/
394int ZEXPORT gzread (file, buf, len)
395    gzFile file;
396    voidp buf;
397    unsigned len;
398{
399    gz_stream *s = (gz_stream*)file;
400    Bytef *start = (Bytef*)buf; /* starting point for crc computation */
401    Byte  *next_out; /* == stream.next_out but not forced far (for MSDOS) */
402
403    if (s == NULL || s->mode != 'r') return Z_STREAM_ERROR;
404
405    if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO) return -1;
406    if (s->z_err == Z_STREAM_END) return 0;  /* EOF */
407
408    next_out = (Byte*)buf;
409    s->stream.next_out = (Bytef*)buf;
410    s->stream.avail_out = len;
411
412    if (s->stream.avail_out && s->back != EOF) {
413        *next_out++ = s->back;
414        s->stream.next_out++;
415        s->stream.avail_out--;
416        s->back = EOF;
417        s->out++;
418        start++;
419        if (s->last) {
420            s->z_err = Z_STREAM_END;
421            return 1;
422        }
423    }
424
425    while (s->stream.avail_out != 0) {
426
427        if (s->transparent) {
428            /* Copy first the lookahead bytes: */
429            uInt n = s->stream.avail_in;
430            if (n > s->stream.avail_out) n = s->stream.avail_out;
431            if (n > 0) {
432                zmemcpy(s->stream.next_out, s->stream.next_in, n);
433                next_out += n;
434                s->stream.next_out = next_out;
435                s->stream.next_in   += n;
436                s->stream.avail_out -= n;
437                s->stream.avail_in  -= n;
438            }
439            if (s->stream.avail_out > 0) {
440                s->stream.avail_out -=
441                    (uInt)fread(next_out, 1, s->stream.avail_out, s->file);
442            }
443            len -= s->stream.avail_out;
444            s->in  += len;
445            s->out += len;
446            if (len == 0) s->z_eof = 1;
447            return (int)len;
448        }
449        if (s->stream.avail_in == 0 && !s->z_eof) {
450
451            errno = 0;
452            s->stream.avail_in = (uInt)fread(s->inbuf, 1, Z_BUFSIZE, s->file);
453            if (s->stream.avail_in == 0) {
454                s->z_eof = 1;
455                if (ferror(s->file)) {
456                    s->z_err = Z_ERRNO;
457                    break;
458                }
459            }
460            s->stream.next_in = s->inbuf;
461        }
462        s->in += s->stream.avail_in;
463        s->out += s->stream.avail_out;
464        s->z_err = inflate(&(s->stream), Z_NO_FLUSH);
465        s->in -= s->stream.avail_in;
466        s->out -= s->stream.avail_out;
467
468        if (s->z_err == Z_STREAM_END) {
469            /* Check CRC and original size */
470            s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
471            start = s->stream.next_out;
472
473            if (getLong(s) != s->crc) {
474                s->z_err = Z_DATA_ERROR;
475            } else {
476                (void)getLong(s);
477                /* The uncompressed length returned by above getlong() may be
478                 * different from s->out in case of concatenated .gz files.
479                 * Check for such files:
480                 */
481                check_header(s);
482                if (s->z_err == Z_OK) {
483                    inflateReset(&(s->stream));
484                    s->crc = crc32(0L, Z_NULL, 0);
485                }
486            }
487        }
488        if (s->z_err != Z_OK || s->z_eof) break;
489    }
490    s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
491
492    if (len == s->stream.avail_out &&
493        (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO))
494        return -1;
495    return (int)(len - s->stream.avail_out);
496}
497
498
499/* ===========================================================================
500      Reads one byte from the compressed file. gzgetc returns this byte
501   or -1 in case of end of file or error.
502*/
503int ZEXPORT gzgetc(file)
504    gzFile file;
505{
506    unsigned char c;
507
508    return gzread(file, &c, 1) == 1 ? c : -1;
509}
510
511
512/* ===========================================================================
513      Push one byte back onto the stream.
514*/
515int ZEXPORT gzungetc(c, file)
516    int c;
517    gzFile file;
518{
519    gz_stream *s = (gz_stream*)file;
520
521    if (s == NULL || s->mode != 'r' || c == EOF || s->back != EOF) return EOF;
522    s->back = c;
523    s->out--;
524    s->last = (s->z_err == Z_STREAM_END);
525    if (s->last) s->z_err = Z_OK;
526    s->z_eof = 0;
527    return c;
528}
529
530
531/* ===========================================================================
532      Reads bytes from the compressed file until len-1 characters are
533   read, or a newline character is read and transferred to buf, or an
534   end-of-file condition is encountered.  The string is then terminated
535   with a null character.
536      gzgets returns buf, or Z_NULL in case of error.
537
538      The current implementation is not optimized at all.
539*/
540char * ZEXPORT gzgets(file, buf, len)
541    gzFile file;
542    char *buf;
543    int len;
544{
545    char *b = buf;
546    if (buf == Z_NULL || len <= 0) return Z_NULL;
547
548    while (--len > 0 && gzread(file, buf, 1) == 1 && *buf++ != '\n') ;
549    *buf = '\0';
550    return b == buf && len > 0 ? Z_NULL : b;
551}
552
553
554#ifndef NO_GZCOMPRESS
555/* ===========================================================================
556     Writes the given number of uncompressed bytes into the compressed file.
557   gzwrite returns the number of bytes actually written (0 in case of error).
558*/
559int ZEXPORT gzwrite (file, buf, len)
560    gzFile file;
561    voidpc buf;
562    unsigned len;
563{
564    gz_stream *s = (gz_stream*)file;
565
566    if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
567
568    s->stream.next_in = (Bytef*)buf;
569    s->stream.avail_in = len;
570
571    while (s->stream.avail_in != 0) {
572
573        if (s->stream.avail_out == 0) {
574
575            s->stream.next_out = s->outbuf;
576            if (fwrite(s->outbuf, 1, Z_BUFSIZE, s->file) != Z_BUFSIZE) {
577                s->z_err = Z_ERRNO;
578                break;
579            }
580            s->stream.avail_out = Z_BUFSIZE;
581        }
582        s->in += s->stream.avail_in;
583        s->out += s->stream.avail_out;
584        s->z_err = deflate(&(s->stream), Z_NO_FLUSH);
585        s->in -= s->stream.avail_in;
586        s->out -= s->stream.avail_out;
587        if (s->z_err != Z_OK) break;
588    }
589    s->crc = crc32(s->crc, (const Bytef *)buf, len);
590
591    return (int)(len - s->stream.avail_in);
592}
593
594
595/* ===========================================================================
596     Converts, formats, and writes the args to the compressed file under
597   control of the format string, as in fprintf. gzprintf returns the number of
598   uncompressed bytes actually written (0 in case of error).
599*/
600#ifdef STDC
601#include <stdarg.h>
602
603int ZEXPORTVA gzprintf (gzFile file, const char *format, /* args */ ...)
604{
605    char buf[Z_PRINTF_BUFSIZE];
606    va_list va;
607    int len;
608
609    buf[sizeof(buf) - 1] = 0;
610    va_start(va, format);
611#ifdef NO_vsnprintf
612#  ifdef HAS_vsprintf_void
613    (void)vsprintf(buf, format, va);
614    va_end(va);
615    for (len = 0; len < sizeof(buf); len++)
616        if (buf[len] == 0) break;
617#  else
618    len = vsprintf(buf, format, va);
619    va_end(va);
620#  endif
621#else
622#  ifdef HAS_vsnprintf_void
623    (void)vsnprintf(buf, sizeof(buf), format, va);
624    va_end(va);
625    len = strlen(buf);
626#  else
627    len = vsnprintf(buf, sizeof(buf), format, va);
628    va_end(va);
629#  endif
630#endif
631    if (len <= 0 || len >= (int)sizeof(buf) || buf[sizeof(buf) - 1] != 0)
632        return 0;
633    return gzwrite(file, buf, (unsigned)len);
634}
635#else /* not ANSI C */
636
637int ZEXPORTVA gzprintf (file, format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
638                       a11, a12, a13, a14, a15, a16, a17, a18, a19, a20)
639    gzFile file;
640    const char *format;
641    int a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
642        a11, a12, a13, a14, a15, a16, a17, a18, a19, a20;
643{
644    char buf[Z_PRINTF_BUFSIZE];
645    int len;
646
647    buf[sizeof(buf) - 1] = 0;
648#ifdef NO_snprintf
649#  ifdef HAS_sprintf_void
650    sprintf(buf, format, a1, a2, a3, a4, a5, a6, a7, a8,
651            a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
652    for (len = 0; len < sizeof(buf); len++)
653        if (buf[len] == 0) break;
654#  else
655    len = sprintf(buf, format, a1, a2, a3, a4, a5, a6, a7, a8,
656                a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
657#  endif
658#else
659#  ifdef HAS_snprintf_void
660    snprintf(buf, sizeof(buf), format, a1, a2, a3, a4, a5, a6, a7, a8,
661             a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
662    len = strlen(buf);
663#  else
664    len = snprintf(buf, sizeof(buf), format, a1, a2, a3, a4, a5, a6, a7, a8,
665                 a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
666#  endif
667#endif
668    if (len <= 0 || len >= sizeof(buf) || buf[sizeof(buf) - 1] != 0)
669        return 0;
670    return gzwrite(file, buf, len);
671}
672#endif
673
674/* ===========================================================================
675      Writes c, converted to an unsigned char, into the compressed file.
676   gzputc returns the value that was written, or -1 in case of error.
677*/
678int ZEXPORT gzputc(file, c)
679    gzFile file;
680    int c;
681{
682    unsigned char cc = (unsigned char) c; /* required for big endian systems */
683
684    return gzwrite(file, &cc, 1) == 1 ? (int)cc : -1;
685}
686
687
688/* ===========================================================================
689      Writes the given null-terminated string to the compressed file, excluding
690   the terminating null character.
691      gzputs returns the number of characters written, or -1 in case of error.
692*/
693int ZEXPORT gzputs(file, s)
694    gzFile file;
695    const char *s;
696{
697    return gzwrite(file, (char*)s, (unsigned)strlen(s));
698}
699
700
701/* ===========================================================================
702     Flushes all pending output into the compressed file. The parameter
703   flush is as in the deflate() function.
704*/
705local int do_flush (file, flush)
706    gzFile file;
707    int flush;
708{
709    uInt len;
710    int done = 0;
711    gz_stream *s = (gz_stream*)file;
712
713    if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
714
715    s->stream.avail_in = 0; /* should be zero already anyway */
716
717    for (;;) {
718        len = Z_BUFSIZE - s->stream.avail_out;
719
720        if (len != 0) {
721            if ((uInt)fwrite(s->outbuf, 1, len, s->file) != len) {
722                s->z_err = Z_ERRNO;
723                return Z_ERRNO;
724            }
725            s->stream.next_out = s->outbuf;
726            s->stream.avail_out = Z_BUFSIZE;
727        }
728        if (done) break;
729        s->out += s->stream.avail_out;
730        s->z_err = deflate(&(s->stream), flush);
731        s->out -= s->stream.avail_out;
732
733        /* Ignore the second of two consecutive flushes: */
734        if (len == 0 && s->z_err == Z_BUF_ERROR) s->z_err = Z_OK;
735
736        /* deflate has finished flushing only when it hasn't used up
737         * all the available space in the output buffer:
738         */
739        done = (s->stream.avail_out != 0 || s->z_err == Z_STREAM_END);
740
741        if (s->z_err != Z_OK && s->z_err != Z_STREAM_END) break;
742    }
743    return  s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
744}
745
746int ZEXPORT gzflush (file, flush)
747     gzFile file;
748     int flush;
749{
750    gz_stream *s = (gz_stream*)file;
751    int err = do_flush (file, flush);
752
753    if (err) return err;
754    fflush(s->file);
755    return  s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
756}
757#endif /* NO_GZCOMPRESS */
758
759/* ===========================================================================
760      Sets the starting position for the next gzread or gzwrite on the given
761   compressed file. The offset represents a number of bytes in the
762      gzseek returns the resulting offset location as measured in bytes from
763   the beginning of the uncompressed stream, or -1 in case of error.
764      SEEK_END is not implemented, returns error.
765      In this version of the library, gzseek can be extremely slow.
766*/
767z_off_t ZEXPORT gzseek (file, offset, whence)
768    gzFile file;
769    z_off_t offset;
770    int whence;
771{
772    gz_stream *s = (gz_stream*)file;
773
774    if (s == NULL || whence == SEEK_END ||
775        s->z_err == Z_ERRNO || s->z_err == Z_DATA_ERROR) {
776        return -1L;
777    }
778
779    if (s->mode == 'w') {
780#ifdef NO_GZCOMPRESS
781        return -1L;
782#else
783        if (whence == SEEK_SET) {
784            offset -= s->in;
785        }
786        if (offset < 0) return -1L;
787
788        /* At this point, offset is the number of zero bytes to write. */
789        if (s->inbuf == Z_NULL) {
790            s->inbuf = (Byte*)ALLOC(Z_BUFSIZE); /* for seeking */
791            if (s->inbuf == Z_NULL) return -1L;
792            zmemzero(s->inbuf, Z_BUFSIZE);
793        }
794        while (offset > 0)  {
795            uInt size = Z_BUFSIZE;
796            if (offset < Z_BUFSIZE) size = (uInt)offset;
797
798            size = gzwrite(file, s->inbuf, size);
799            if (size == 0) return -1L;
800
801            offset -= size;
802        }
803        return s->in;
804#endif
805    }
806    /* Rest of function is for reading only */
807
808    /* compute absolute position */
809    if (whence == SEEK_CUR) {
810        offset += s->out;
811    }
812    if (offset < 0) return -1L;
813
814    if (s->transparent) {
815        /* map to fseek */
816        s->back = EOF;
817        s->stream.avail_in = 0;
818        s->stream.next_in = s->inbuf;
819        if (fseek(s->file, offset, SEEK_SET) < 0) return -1L;
820
821        s->in = s->out = offset;
822        return offset;
823    }
824
825    /* For a negative seek, rewind and use positive seek */
826    if (offset >= s->out) {
827        offset -= s->out;
828    } else if (gzrewind(file) < 0) {
829        return -1L;
830    }
831    /* offset is now the number of bytes to skip. */
832
833    if (offset != 0 && s->outbuf == Z_NULL) {
834        s->outbuf = (Byte*)ALLOC(Z_BUFSIZE);
835        if (s->outbuf == Z_NULL) return -1L;
836    }
837    if (offset && s->back != EOF) {
838        s->back = EOF;
839        s->out++;
840        offset--;
841        if (s->last) s->z_err = Z_STREAM_END;
842    }
843    while (offset > 0)  {
844        int size = Z_BUFSIZE;
845        if (offset < Z_BUFSIZE) size = (int)offset;
846
847        size = gzread(file, s->outbuf, (uInt)size);
848        if (size <= 0) return -1L;
849        offset -= size;
850    }
851    return s->out;
852}
853
854/* ===========================================================================
855     Rewinds input file.
856*/
857int ZEXPORT gzrewind (file)
858    gzFile file;
859{
860    gz_stream *s = (gz_stream*)file;
861
862    if (s == NULL || s->mode != 'r') return -1;
863
864    s->z_err = Z_OK;
865    s->z_eof = 0;
866    s->back = EOF;
867    s->stream.avail_in = 0;
868    s->stream.next_in = s->inbuf;
869    s->crc = crc32(0L, Z_NULL, 0);
870    if (!s->transparent) (void)inflateReset(&s->stream);
871    s->in = 0;
872    s->out = 0;
873    return fseek(s->file, s->start, SEEK_SET);
874}
875
876/* ===========================================================================
877     Returns the starting position for the next gzread or gzwrite on the
878   given compressed file. This position represents a number of bytes in the
879   uncompressed data stream.
880*/
881z_off_t ZEXPORT gztell (file)
882    gzFile file;
883{
884    return gzseek(file, 0L, SEEK_CUR);
885}
886
887/* ===========================================================================
888     Returns 1 when EOF has previously been detected reading the given
889   input stream, otherwise zero.
890*/
891int ZEXPORT gzeof (file)
892    gzFile file;
893{
894    gz_stream *s = (gz_stream*)file;
895
896    /* With concatenated compressed files that can have embedded
897     * crc trailers, z_eof is no longer the only/best indicator of EOF
898     * on a gz_stream. Handle end-of-stream error explicitly here.
899     */
900    if (s == NULL || s->mode != 'r') return 0;
901    if (s->z_eof) return 1;
902    return s->z_err == Z_STREAM_END;
903}
904
905/* ===========================================================================
906     Returns 1 if reading and doing so transparently, otherwise zero.
907*/
908int ZEXPORT gzdirect (file)
909    gzFile file;
910{
911    gz_stream *s = (gz_stream*)file;
912
913    if (s == NULL || s->mode != 'r') return 0;
914    return s->transparent;
915}
916
917/* ===========================================================================
918   Outputs a long in LSB order to the given file
919*/
920local void putLong (file, x)
921    FILE *file;
922    uLong x;
923{
924    int n;
925    for (n = 0; n < 4; n++) {
926        fputc((int)(x & 0xff), file);
927        x >>= 8;
928    }
929}
930
931/* ===========================================================================
932   Reads a long in LSB order from the given gz_stream. Sets z_err in case
933   of error.
934*/
935local uLong getLong (s)
936    gz_stream *s;
937{
938    uLong x = (uLong)get_byte(s);
939    int c;
940
941    x += ((uLong)get_byte(s))<<8;
942    x += ((uLong)get_byte(s))<<16;
943    c = get_byte(s);
944    if (c == EOF) s->z_err = Z_DATA_ERROR;
945    x += ((uLong)c)<<24;
946    return x;
947}
948
949/* ===========================================================================
950     Flushes all pending output if necessary, closes the compressed file
951   and deallocates all the (de)compression state.
952*/
953int ZEXPORT gzclose (file)
954    gzFile file;
955{
956    gz_stream *s = (gz_stream*)file;
957
958    if (s == NULL) return Z_STREAM_ERROR;
959
960    if (s->mode == 'w') {
961#ifdef NO_GZCOMPRESS
962        return Z_STREAM_ERROR;
963#else
964        if (do_flush (file, Z_FINISH) != Z_OK)
965            return destroy((gz_stream*)file);
966
967        putLong (s->file, s->crc);
968        putLong (s->file, (uLong)(s->in & 0xffffffff));
969#endif
970    }
971    return destroy((gz_stream*)file);
972}
973
974#ifdef STDC
975#  define zstrerror(errnum) strerror(errnum)
976#else
977#  define zstrerror(errnum) ""
978#endif
979
980/* ===========================================================================
981     Returns the error message for the last error which occurred on the
982   given compressed file. errnum is set to zlib error number. If an
983   error occurred in the file system and not in the compression library,
984   errnum is set to Z_ERRNO and the application may consult errno
985   to get the exact error code.
986*/
987const char * ZEXPORT gzerror (file, errnum)
988    gzFile file;
989    int *errnum;
990{
991    char *m;
992    gz_stream *s = (gz_stream*)file;
993
994    if (s == NULL) {
995        *errnum = Z_STREAM_ERROR;
996        return (const char*)ERR_MSG(Z_STREAM_ERROR);
997    }
998    *errnum = s->z_err;
999    if (*errnum == Z_OK) return (const char*)"";
1000
1001    m = (char*)(*errnum == Z_ERRNO ? zstrerror(errno) : s->stream.msg);
1002
1003    if (m == NULL || *m == '\0') m = (char*)ERR_MSG(s->z_err);
1004
1005    TRYFREE(s->msg);
1006    s->msg = (char*)ALLOC(strlen(s->path) + strlen(m) + 3);
1007    if (s->msg == Z_NULL) return (const char*)ERR_MSG(Z_MEM_ERROR);
1008    strcpy(s->msg, s->path);
1009    strcat(s->msg, ": ");
1010    strcat(s->msg, m);
1011    return (const char*)s->msg;
1012}
1013
1014/* ===========================================================================
1015     Clear the error and end-of-file flags, and do the same for the real file.
1016*/
1017void ZEXPORT gzclearerr (file)
1018    gzFile file;
1019{
1020    gz_stream *s = (gz_stream*)file;
1021
1022    if (s == NULL) return;
1023    if (s->z_err != Z_STREAM_END) s->z_err = Z_OK;
1024    s->z_eof = 0;
1025    clearerr(s->file);
1026}
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