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