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