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: //poco/Main/Foundation/src/gzio.c#8 $ */
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}
1027