gzio.c@ 8612

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export libpng and zlib so Windows and OS/2 builds cleanly.
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1	/* gzio.c -- IO on .gz files
2	* Copyright (C) 1995-2003 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: gzio.c,v 1.1 2004/11/15 16:42:25 bird Exp $ */
9
10	#include <stdio.h>
11
12	#include "zutil.h"
13
14	#ifdef NO_DEFLATE /* for compatiblity 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	static 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
56	typedef 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
76	local gzFile gz_open OF((const char path, const char mode, int fd));
77	local int do_flush OF((gzFile file, int flush));
78	local int get_byte OF((gz_stream *s));
79	local void check_header OF((gz_stream *s));
80	local int destroy OF((gz_stream *s));
81	local void putLong OF((FILE *file, uLong x));
82	local 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	*/
93	local 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	*/
208	gzFile 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	*/
219	gzFile ZEXPORT gzdopen (fd, mode)
220	int fd;
221	const char *mode;
222	{
223	char name[20];
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	*/
234	int 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	*/
261	local 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 = 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	*/
288	local 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 = 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	*/
355	local 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	*/
394	int 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	if (s->last) {
419	s->z_err = Z_STREAM_END;
420	return 1;
421	}
422	}
423
424	while (s->stream.avail_out != 0) {
425
426	if (s->transparent) {
427	/* Copy first the lookahead bytes: */
428	uInt n = s->stream.avail_in;
429	if (n > s->stream.avail_out) n = s->stream.avail_out;
430	if (n > 0) {
431	zmemcpy(s->stream.next_out, s->stream.next_in, n);
432	next_out += n;
433	s->stream.next_out = next_out;
434	s->stream.next_in += n;
435	s->stream.avail_out -= n;
436	s->stream.avail_in -= n;
437	}
438	if (s->stream.avail_out > 0) {
439	s->stream.avail_out -= fread(next_out, 1, s->stream.avail_out,
440	s->file);
441	}
442	len -= s->stream.avail_out;
443	s->in += len;
444	s->out += len;
445	if (len == 0) s->z_eof = 1;
446	return (int)len;
447	}
448	if (s->stream.avail_in == 0 && !s->z_eof) {
449
450	errno = 0;
451	s->stream.avail_in = fread(s->inbuf, 1, Z_BUFSIZE, s->file);
452	if (s->stream.avail_in == 0) {
453	s->z_eof = 1;
454	if (ferror(s->file)) {
455	s->z_err = Z_ERRNO;
456	break;
457	}
458	}
459	s->stream.next_in = s->inbuf;
460	}
461	s->in += s->stream.avail_in;
462	s->out += s->stream.avail_out;
463	s->z_err = inflate(&(s->stream), Z_NO_FLUSH);
464	s->in -= s->stream.avail_in;
465	s->out -= s->stream.avail_out;
466
467	if (s->z_err == Z_STREAM_END) {
468	/* Check CRC and original size */
469	s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
470	start = s->stream.next_out;
471
472	if (getLong(s) != s->crc) {
473	s->z_err = Z_DATA_ERROR;
474	} else {
475	(void)getLong(s);
476	/* The uncompressed length returned by above getlong() may be
477	* different from s->out in case of concatenated .gz files.
478	* Check for such files:
479	*/
480	check_header(s);
481	if (s->z_err == Z_OK) {
482	inflateReset(&(s->stream));
483	s->crc = crc32(0L, Z_NULL, 0);
484	}
485	}
486	}
487	if (s->z_err != Z_OK \|\| s->z_eof) break;
488	}
489	s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
490
491	return (int)(len - s->stream.avail_out);
492	}
493
494
495	/* ===========================================================================
496	Reads one byte from the compressed file. gzgetc returns this byte
497	or -1 in case of end of file or error.
498	*/
499	int ZEXPORT gzgetc(file)
500	gzFile file;
501	{
502	unsigned char c;
503
504	return gzread(file, &c, 1) == 1 ? c : -1;
505	}
506
507
508	/* ===========================================================================
509	Push one byte back onto the stream.
510	*/
511	int ZEXPORT gzungetc(c, file)
512	int c;
513	gzFile file;
514	{
515	gz_stream s = (gz_stream)file;
516
517	if (s == NULL \|\| s->mode != 'r' \|\| c == EOF \|\| s->back != EOF) return EOF;
518	s->back = c;
519	s->out--;
520	s->last = (s->z_err == Z_STREAM_END);
521	if (s->last) s->z_err = Z_OK;
522	s->z_eof = 0;
523	return c;
524	}
525
526
527	/* ===========================================================================
528	Reads bytes from the compressed file until len-1 characters are
529	read, or a newline character is read and transferred to buf, or an
530	end-of-file condition is encountered. The string is then terminated
531	with a null character.
532	gzgets returns buf, or Z_NULL in case of error.
533
534	The current implementation is not optimized at all.
535	*/
536	char * ZEXPORT gzgets(file, buf, len)
537	gzFile file;
538	char *buf;
539	int len;
540	{
541	char *b = buf;
542	if (buf == Z_NULL \|\| len <= 0) return Z_NULL;
543
544	while (--len > 0 && gzread(file, buf, 1) == 1 && *buf++ != '\n') ;
545	*buf = '\0';
546	return b == buf && len > 0 ? Z_NULL : b;
547	}
548
549
550	#ifndef NO_GZCOMPRESS
551	/* ===========================================================================
552	Writes the given number of uncompressed bytes into the compressed file.
553	gzwrite returns the number of bytes actually written (0 in case of error).
554	*/
555	int ZEXPORT gzwrite (file, buf, len)
556	gzFile file;
557	voidpc buf;
558	unsigned len;
559	{
560	gz_stream s = (gz_stream)file;
561
562	if (s == NULL \|\| s->mode != 'w') return Z_STREAM_ERROR;
563
564	s->stream.next_in = (Bytef*)buf;
565	s->stream.avail_in = len;
566
567	while (s->stream.avail_in != 0) {
568
569	if (s->stream.avail_out == 0) {
570
571	s->stream.next_out = s->outbuf;
572	if (fwrite(s->outbuf, 1, Z_BUFSIZE, s->file) != Z_BUFSIZE) {
573	s->z_err = Z_ERRNO;
574	break;
575	}
576	s->stream.avail_out = Z_BUFSIZE;
577	}
578	s->in += s->stream.avail_in;
579	s->out += s->stream.avail_out;
580	s->z_err = deflate(&(s->stream), Z_NO_FLUSH);
581	s->in -= s->stream.avail_in;
582	s->out -= s->stream.avail_out;
583	if (s->z_err != Z_OK) break;
584	}
585	s->crc = crc32(s->crc, (const Bytef *)buf, len);
586
587	return (int)(len - s->stream.avail_in);
588	}
589
590
591	/* ===========================================================================
592	Converts, formats, and writes the args to the compressed file under
593	control of the format string, as in fprintf. gzprintf returns the number of
594	uncompressed bytes actually written (0 in case of error).
595	*/
596	#ifdef STDC
597	#include <stdarg.h>
598
599	int ZEXPORTVA gzprintf (gzFile file, const char format, / args */ ...)
600	{
601	char buf[Z_PRINTF_BUFSIZE];
602	va_list va;
603	int len;
604
605	buf[sizeof(buf) - 1] = 0;
606	va_start(va, format);
607	#ifdef NO_vsnprintf
608	# ifdef HAS_vsprintf_void
609	(void)vsprintf(buf, format, va);
610	va_end(va);
611	for (len = 0; len < sizeof(buf); len++)
612	if (buf[len] == 0) break;
613	# else
614	len = vsprintf(buf, format, va);
615	va_end(va);
616	# endif
617	#else
618	# ifdef HAS_vsnprintf_void
619	(void)vsnprintf(buf, sizeof(buf), format, va);
620	va_end(va);
621	len = strlen(buf);
622	# else
623	len = vsnprintf(buf, sizeof(buf), format, va);
624	va_end(va);
625	# endif
626	#endif
627	if (len <= 0 \|\| len >= (int)sizeof(buf) \|\| buf[sizeof(buf) - 1] != 0)
628	return 0;
629	return gzwrite(file, buf, (unsigned)len);
630	}
631	#else /* not ANSI C */
632
633	int ZEXPORTVA gzprintf (file, format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
634	a11, a12, a13, a14, a15, a16, a17, a18, a19, a20)
635	gzFile file;
636	const char *format;
637	int a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
638	a11, a12, a13, a14, a15, a16, a17, a18, a19, a20;
639	{
640	char buf[Z_PRINTF_BUFSIZE];
641	int len;
642
643	buf[sizeof(buf) - 1] = 0;
644	#ifdef NO_snprintf
645	# ifdef HAS_sprintf_void
646	sprintf(buf, format, a1, a2, a3, a4, a5, a6, a7, a8,
647	a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
648	for (len = 0; len < sizeof(buf); len++)
649	if (buf[len] == 0) break;
650	# else
651	len = sprintf(buf, format, a1, a2, a3, a4, a5, a6, a7, a8,
652	a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
653	# endif
654	#else
655	# ifdef HAS_snprintf_void
656	snprintf(buf, sizeof(buf), format, a1, a2, a3, a4, a5, a6, a7, a8,
657	a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
658	len = strlen(buf);
659	# else
660	len = 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	# endif
663	#endif
664	if (len <= 0 \|\| len >= sizeof(buf) \|\| buf[sizeof(buf) - 1] != 0)
665	return 0;
666	return gzwrite(file, buf, len);
667	}
668	#endif
669
670	/* ===========================================================================
671	Writes c, converted to an unsigned char, into the compressed file.
672	gzputc returns the value that was written, or -1 in case of error.
673	*/
674	int ZEXPORT gzputc(file, c)
675	gzFile file;
676	int c;
677	{
678	unsigned char cc = (unsigned char) c; /* required for big endian systems */
679
680	return gzwrite(file, &cc, 1) == 1 ? (int)cc : -1;
681	}
682
683
684	/* ===========================================================================
685	Writes the given null-terminated string to the compressed file, excluding
686	the terminating null character.
687	gzputs returns the number of characters written, or -1 in case of error.
688	*/
689	int ZEXPORT gzputs(file, s)
690	gzFile file;
691	const char *s;
692	{
693	return gzwrite(file, (char*)s, (unsigned)strlen(s));
694	}
695
696
697	/* ===========================================================================
698	Flushes all pending output into the compressed file. The parameter
699	flush is as in the deflate() function.
700	*/
701	local int do_flush (file, flush)
702	gzFile file;
703	int flush;
704	{
705	uInt len;
706	int done = 0;
707	gz_stream s = (gz_stream)file;
708
709	if (s == NULL \|\| s->mode != 'w') return Z_STREAM_ERROR;
710
711	s->stream.avail_in = 0; /* should be zero already anyway */
712
713	for (;;) {
714	len = Z_BUFSIZE - s->stream.avail_out;
715
716	if (len != 0) {
717	if ((uInt)fwrite(s->outbuf, 1, len, s->file) != len) {
718	s->z_err = Z_ERRNO;
719	return Z_ERRNO;
720	}
721	s->stream.next_out = s->outbuf;
722	s->stream.avail_out = Z_BUFSIZE;
723	}
724	if (done) break;
725	s->out += s->stream.avail_out;
726	s->z_err = deflate(&(s->stream), flush);
727	s->out -= s->stream.avail_out;
728
729	/* Ignore the second of two consecutive flushes: */
730	if (len == 0 && s->z_err == Z_BUF_ERROR) s->z_err = Z_OK;
731
732	/* deflate has finished flushing only when it hasn't used up
733	* all the available space in the output buffer:
734	*/
735	done = (s->stream.avail_out != 0 \|\| s->z_err == Z_STREAM_END);
736
737	if (s->z_err != Z_OK && s->z_err != Z_STREAM_END) break;
738	}
739	return s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
740	}
741
742	int ZEXPORT gzflush (file, flush)
743	gzFile file;
744	int flush;
745	{
746	gz_stream s = (gz_stream)file;
747	int err = do_flush (file, flush);
748
749	if (err) return err;
750	fflush(s->file);
751	return s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
752	}
753	#endif /* NO_GZCOMPRESS */
754
755	/* ===========================================================================
756	Sets the starting position for the next gzread or gzwrite on the given
757	compressed file. The offset represents a number of bytes in the
758	gzseek returns the resulting offset location as measured in bytes from
759	the beginning of the uncompressed stream, or -1 in case of error.
760	SEEK_END is not implemented, returns error.
761	In this version of the library, gzseek can be extremely slow.
762	*/
763	z_off_t ZEXPORT gzseek (file, offset, whence)
764	gzFile file;
765	z_off_t offset;
766	int whence;
767	{
768	gz_stream s = (gz_stream)file;
769
770	if (s == NULL \|\| whence == SEEK_END \|\|
771	s->z_err == Z_ERRNO \|\| s->z_err == Z_DATA_ERROR) {
772	return -1L;
773	}
774
775	if (s->mode == 'w') {
776	#ifdef NO_GZCOMPRESS
777	return -1L;
778	#else
779	if (whence == SEEK_SET) {
780	offset -= s->in;
781	}
782	if (offset < 0) return -1L;
783
784	/* At this point, offset is the number of zero bytes to write. */
785	if (s->inbuf == Z_NULL) {
786	s->inbuf = (Byte)ALLOC(Z_BUFSIZE); / for seeking */
787	if (s->inbuf == Z_NULL) return -1L;
788	zmemzero(s->inbuf, Z_BUFSIZE);
789	}
790	while (offset > 0) {
791	uInt size = Z_BUFSIZE;
792	if (offset < Z_BUFSIZE) size = (uInt)offset;
793
794	size = gzwrite(file, s->inbuf, size);
795	if (size == 0) return -1L;
796
797	offset -= size;
798	}
799	return s->in;
800	#endif
801	}
802	/* Rest of function is for reading only */
803
804	/* compute absolute position */
805	if (whence == SEEK_CUR) {
806	offset += s->out;
807	}
808	if (offset < 0) return -1L;
809
810	if (s->transparent) {
811	/* map to fseek */
812	s->back = EOF;
813	s->stream.avail_in = 0;
814	s->stream.next_in = s->inbuf;
815	if (fseek(s->file, offset, SEEK_SET) < 0) return -1L;
816
817	s->in = s->out = offset;
818	return offset;
819	}
820
821	/* For a negative seek, rewind and use positive seek */
822	if (offset >= s->out) {
823	offset -= s->out;
824	} else if (gzrewind(file) < 0) {
825	return -1L;
826	}
827	/* offset is now the number of bytes to skip. */
828
829	if (offset != 0 && s->outbuf == Z_NULL) {
830	s->outbuf = (Byte*)ALLOC(Z_BUFSIZE);
831	if (s->outbuf == Z_NULL) return -1L;
832	}
833	if (offset && s->back != EOF) {
834	s->back = EOF;
835	s->out++;
836	offset--;
837	if (s->last) s->z_err = Z_STREAM_END;
838	}
839	while (offset > 0) {
840	int size = Z_BUFSIZE;
841	if (offset < Z_BUFSIZE) size = (int)offset;
842
843	size = gzread(file, s->outbuf, (uInt)size);
844	if (size <= 0) return -1L;
845	offset -= size;
846	}
847	return s->out;
848	}
849
850	/* ===========================================================================
851	Rewinds input file.
852	*/
853	int ZEXPORT gzrewind (file)
854	gzFile file;
855	{
856	gz_stream s = (gz_stream)file;
857
858	if (s == NULL \|\| s->mode != 'r') return -1;
859
860	s->z_err = Z_OK;
861	s->z_eof = 0;
862	s->back = EOF;
863	s->stream.avail_in = 0;
864	s->stream.next_in = s->inbuf;
865	s->crc = crc32(0L, Z_NULL, 0);
866	if (!s->transparent) (void)inflateReset(&s->stream);
867	s->in = 0;
868	s->out = 0;
869	return fseek(s->file, s->start, SEEK_SET);
870	}
871
872	/* ===========================================================================
873	Returns the starting position for the next gzread or gzwrite on the
874	given compressed file. This position represents a number of bytes in the
875	uncompressed data stream.
876	*/
877	z_off_t ZEXPORT gztell (file)
878	gzFile file;
879	{
880	return gzseek(file, 0L, SEEK_CUR);
881	}
882
883	/* ===========================================================================
884	Returns 1 when EOF has previously been detected reading the given
885	input stream, otherwise zero.
886	*/
887	int ZEXPORT gzeof (file)
888	gzFile file;
889	{
890	gz_stream s = (gz_stream)file;
891
892	/* With concatenated compressed files that can have embedded
893	* crc trailers, z_eof is no longer the only/best indicator of EOF
894	* on a gz_stream. Handle end-of-stream error explicitly here.
895	*/
896	if (s == NULL \|\| s->mode != 'r') return 0;
897	if (s->z_eof) return 1;
898	return s->z_err == Z_STREAM_END;
899	}
900
901	/* ===========================================================================
902	Outputs a long in LSB order to the given file
903	*/
904	local void putLong (file, x)
905	FILE *file;
906	uLong x;
907	{
908	int n;
909	for (n = 0; n < 4; n++) {
910	fputc((int)(x & 0xff), file);
911	x >>= 8;
912	}
913	}
914
915	/* ===========================================================================
916	Reads a long in LSB order from the given gz_stream. Sets z_err in case
917	of error.
918	*/
919	local uLong getLong (s)
920	gz_stream *s;
921	{
922	uLong x = (uLong)get_byte(s);
923	int c;
924
925	x += ((uLong)get_byte(s))<<8;
926	x += ((uLong)get_byte(s))<<16;
927	c = get_byte(s);
928	if (c == EOF) s->z_err = Z_DATA_ERROR;
929	x += ((uLong)c)<<24;
930	return x;
931	}
932
933	/* ===========================================================================
934	Flushes all pending output if necessary, closes the compressed file
935	and deallocates all the (de)compression state.
936	*/
937	int ZEXPORT gzclose (file)
938	gzFile file;
939	{
940	int err;
941	gz_stream s = (gz_stream)file;
942
943	if (s == NULL) return Z_STREAM_ERROR;
944
945	if (s->mode == 'w') {
946	#ifdef NO_GZCOMPRESS
947	return Z_STREAM_ERROR;
948	#else
949	err = do_flush (file, Z_FINISH);
950	if (err != Z_OK) return destroy((gz_stream*)file);
951
952	putLong (s->file, s->crc);
953	putLong (s->file, (uLong)(s->in & 0xffffffff));
954	#endif
955	}
956	return destroy((gz_stream*)file);
957	}
958
959	/* ===========================================================================
960	Returns the error message for the last error which occured on the
961	given compressed file. errnum is set to zlib error number. If an
962	error occured in the file system and not in the compression library,
963	errnum is set to Z_ERRNO and the application may consult errno
964	to get the exact error code.
965	*/
966	const char * ZEXPORT gzerror (file, errnum)
967	gzFile file;
968	int *errnum;
969	{
970	char *m;
971	gz_stream s = (gz_stream)file;
972
973	if (s == NULL) {
974	*errnum = Z_STREAM_ERROR;
975	return (const char*)ERR_MSG(Z_STREAM_ERROR);
976	}
977	*errnum = s->z_err;
978	if (errnum == Z_OK) return (const char)"";
979
980	m = (char)(errnum == Z_ERRNO ? zstrerror(errno) : s->stream.msg);
981
982	if (m == NULL \|\| m == '\0') m = (char)ERR_MSG(s->z_err);
983
984	TRYFREE(s->msg);
985	s->msg = (char*)ALLOC(strlen(s->path) + strlen(m) + 3);
986	if (s->msg == Z_NULL) return (const char*)ERR_MSG(Z_MEM_ERROR);
987	strcpy(s->msg, s->path);
988	strcat(s->msg, ": ");
989	strcat(s->msg, m);
990	return (const char*)s->msg;
991	}
992
993	/* ===========================================================================
994	Clear the error and end-of-file flags, and do the same for the real file.
995	*/
996	void ZEXPORT gzclearerr (file)
997	gzFile file;
998	{
999	gz_stream s = (gz_stream)file;
1000
1001	if (s == NULL) return;
1002	if (s->z_err != Z_STREAM_END) s->z_err = Z_OK;
1003	s->z_eof = 0;
1004	clearerr(s->file);
1005	}

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source: vbox/trunk/src/libs/zlib-1.2.1/gzio.c@ 8612

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