1: /* zlib.h -- interface of the 'zlib' general purpose compression library
2: version 1.2.5, April 19th, 2010
3:
4: Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler
5:
6: This software is provided 'as-is', without any express or implied
7: warranty. In no event will the authors be held liable for any damages
8: arising from the use of this software.
9:
10: Permission is granted to anyone to use this software for any purpose,
11: including commercial applications, and to alter it and redistribute it
12: freely, subject to the following restrictions:
13:
14: 1. The origin of this software must not be misrepresented; you must not
15: claim that you wrote the original software. If you use this software
16: in a product, an acknowledgment in the product documentation would be
17: appreciated but is not required.
18: 2. Altered source versions must be plainly marked as such, and must not be
19: misrepresented as being the original software.
20: 3. This notice may not be removed or altered from any source distribution.
21:
22: Jean-loup Gailly Mark Adler
23: jloup@gzip.org madler@alumni.caltech.edu
24:
25:
26: The data format used by the zlib library is described by RFCs (Request for
27: Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt
28: (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
29: */
30:
31: #ifndef ZLIB_H
32: #define ZLIB_H
33:
34: #include "zconf.h"
35:
36: #ifdef __cplusplus
37: extern "C" {
38: #endif
39:
40: #define ZLIB_VERSION "1.2.5"
41: #define ZLIB_VERNUM 0x1250
42: #define ZLIB_VER_MAJOR 1
43: #define ZLIB_VER_MINOR 2
44: #define ZLIB_VER_REVISION 5
45: #define ZLIB_VER_SUBREVISION 0
46:
47: /*
48: The 'zlib' compression library provides in-memory compression and
49: decompression functions, including integrity checks of the uncompressed data.
50: This version of the library supports only one compression method (deflation)
51: but other algorithms will be added later and will have the same stream
52: interface.
53:
54: Compression can be done in a single step if the buffers are large enough,
55: or can be done by repeated calls of the compression function. In the latter
56: case, the application must provide more input and/or consume the output
57: (providing more output space) before each call.
58:
59: The compressed data format used by default by the in-memory functions is
60: the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
61: around a deflate stream, which is itself documented in RFC 1951.
62:
63: The library also supports reading and writing files in gzip (.gz) format
64: with an interface similar to that of stdio using the functions that start
65: with "gz". The gzip format is different from the zlib format. gzip is a
66: gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
67:
68: This library can optionally read and write gzip streams in memory as well.
69:
70: The zlib format was designed to be compact and fast for use in memory
71: and on communications channels. The gzip format was designed for single-
72: file compression on file systems, has a larger header than zlib to maintain
73: directory information, and uses a different, slower check method than zlib.
74:
75: The library does not install any signal handler. The decoder checks
76: the consistency of the compressed data, so the library should never crash
77: even in case of corrupted input.
78: */
79:
80: typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
81: typedef void (*free_func) OF((voidpf opaque, voidpf address));
82:
83: struct internal_state;
84:
85: typedef struct z_stream_s {
86: Bytef *next_in; /* next input byte */
87: uInt avail_in; /* number of bytes available at next_in */
88: uLong total_in; /* total nb of input bytes read so far */
89:
90: Bytef *next_out; /* next output byte should be put there */
91: uInt avail_out; /* remaining free space at next_out */
92: uLong total_out; /* total nb of bytes output so far */
93:
94: char *msg; /* last error message, NULL if no error */
95: struct internal_state FAR *state; /* not visible by applications */
96:
97: alloc_func zalloc; /* used to allocate the internal state */
98: free_func zfree; /* used to free the internal state */
99: voidpf opaque; /* private data object passed to zalloc and zfree */
100:
101: int data_type; /* best guess about the data type: binary or text */
102: uLong adler; /* adler32 value of the uncompressed data */
103: uLong reserved; /* reserved for future use */
104: } z_stream;
105:
106: typedef z_stream FAR *z_streamp;
107:
108: /*
109: gzip header information passed to and from zlib routines. See RFC 1952
110: for more details on the meanings of these fields.
111: */
112: typedef struct gz_header_s {
113: int text; /* true if compressed data believed to be text */
114: uLong time; /* modification time */
115: int xflags; /* extra flags (not used when writing a gzip file) */
116: int os; /* operating system */
117: Bytef *extra; /* pointer to extra field or Z_NULL if none */
118: uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
119: uInt extra_max; /* space at extra (only when reading header) */
120: Bytef *name; /* pointer to zero-terminated file name or Z_NULL */
121: uInt name_max; /* space at name (only when reading header) */
122: Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */
123: uInt comm_max; /* space at comment (only when reading header) */
124: int hcrc; /* true if there was or will be a header crc */
125: int done; /* true when done reading gzip header (not used
126: when writing a gzip file) */
127: } gz_header;
128:
129: typedef gz_header FAR *gz_headerp;
130:
131: /*
132: The application must update next_in and avail_in when avail_in has dropped
133: to zero. It must update next_out and avail_out when avail_out has dropped
134: to zero. The application must initialize zalloc, zfree and opaque before
135: calling the init function. All other fields are set by the compression
136: library and must not be updated by the application.
137:
138: The opaque value provided by the application will be passed as the first
139: parameter for calls of zalloc and zfree. This can be useful for custom
140: memory management. The compression library attaches no meaning to the
141: opaque value.
142:
143: zalloc must return Z_NULL if there is not enough memory for the object.
144: If zlib is used in a multi-threaded application, zalloc and zfree must be
145: thread safe.
146:
147: On 16-bit systems, the functions zalloc and zfree must be able to allocate
148: exactly 65536 bytes, but will not be required to allocate more than this if
149: the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers
150: returned by zalloc for objects of exactly 65536 bytes *must* have their
151: offset normalized to zero. The default allocation function provided by this
152: library ensures this (see zutil.c). To reduce memory requirements and avoid
153: any allocation of 64K objects, at the expense of compression ratio, compile
154: the library with -DMAX_WBITS=14 (see zconf.h).
155:
156: The fields total_in and total_out can be used for statistics or progress
157: reports. After compression, total_in holds the total size of the
158: uncompressed data and may be saved for use in the decompressor (particularly
159: if the decompressor wants to decompress everything in a single step).
160: */
161:
162: /* constants */
163:
164: #define Z_NO_FLUSH 0
165: #define Z_PARTIAL_FLUSH 1
166: #define Z_SYNC_FLUSH 2
167: #define Z_FULL_FLUSH 3
168: #define Z_FINISH 4
169: #define Z_BLOCK 5
170: #define Z_TREES 6
171: /* Allowed flush values; see deflate() and inflate() below for details */
172:
173: #define Z_OK 0
174: #define Z_STREAM_END 1
175: #define Z_NEED_DICT 2
176: #define Z_ERRNO (-1)
177: #define Z_STREAM_ERROR (-2)
178: #define Z_DATA_ERROR (-3)
179: #define Z_MEM_ERROR (-4)
180: #define Z_BUF_ERROR (-5)
181: #define Z_VERSION_ERROR (-6)
182: /* Return codes for the compression/decompression functions. Negative values
183: * are errors, positive values are used for special but normal events.
184: */
185:
186: #define Z_NO_COMPRESSION 0
187: #define Z_BEST_SPEED 1
188: #define Z_BEST_COMPRESSION 9
189: #define Z_DEFAULT_COMPRESSION (-1)
190: /* compression levels */
191:
192: #define Z_FILTERED 1
193: #define Z_HUFFMAN_ONLY 2
194: #define Z_RLE 3
195: #define Z_FIXED 4
196: #define Z_DEFAULT_STRATEGY 0
197: /* compression strategy; see deflateInit2() below for details */
198:
199: #define Z_BINARY 0
200: #define Z_TEXT 1
201: #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
202: #define Z_UNKNOWN 2
203: /* Possible values of the data_type field (though see inflate()) */
204:
205: #define Z_DEFLATED 8
206: /* The deflate compression method (the only one supported in this version) */
207:
208: #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
209:
210: #define zlib_version zlibVersion()
211: /* for compatibility with versions < 1.0.2 */
212:
213:
214: /* basic functions */
215:
216: ZEXTERN const char * ZEXPORT zlibVersion OF((void));
217: /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
218: If the first character differs, the library code actually used is not
219: compatible with the zlib.h header file used by the application. This check
220: is automatically made by deflateInit and inflateInit.
221: */
222:
223: /*
224: ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
225:
226: Initializes the internal stream state for compression. The fields
227: zalloc, zfree and opaque must be initialized before by the caller. If
228: zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
229: allocation functions.
230:
231: The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
232: 1 gives best speed, 9 gives best compression, 0 gives no compression at all
233: (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
234: requests a default compromise between speed and compression (currently
235: equivalent to level 6).
236:
237: deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
238: memory, Z_STREAM_ERROR if level is not a valid compression level, or
239: Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
240: with the version assumed by the caller (ZLIB_VERSION). msg is set to null
241: if there is no error message. deflateInit does not perform any compression:
242: this will be done by deflate().
243: */
244:
245:
246: ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
247: /*
248: deflate compresses as much data as possible, and stops when the input
249: buffer becomes empty or the output buffer becomes full. It may introduce
250: some output latency (reading input without producing any output) except when
251: forced to flush.
252:
253: The detailed semantics are as follows. deflate performs one or both of the
254: following actions:
255:
256: - Compress more input starting at next_in and update next_in and avail_in
257: accordingly. If not all input can be processed (because there is not
258: enough room in the output buffer), next_in and avail_in are updated and
259: processing will resume at this point for the next call of deflate().
260:
261: - Provide more output starting at next_out and update next_out and avail_out
262: accordingly. This action is forced if the parameter flush is non zero.
263: Forcing flush frequently degrades the compression ratio, so this parameter
264: should be set only when necessary (in interactive applications). Some
265: output may be provided even if flush is not set.
266:
267: Before the call of deflate(), the application should ensure that at least
268: one of the actions is possible, by providing more input and/or consuming more
269: output, and updating avail_in or avail_out accordingly; avail_out should
270: never be zero before the call. The application can consume the compressed
271: output when it wants, for example when the output buffer is full (avail_out
272: == 0), or after each call of deflate(). If deflate returns Z_OK and with
273: zero avail_out, it must be called again after making room in the output
274: buffer because there might be more output pending.
275:
276: Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
277: decide how much data to accumulate before producing output, in order to
278: maximize compression.
279:
280: If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
281: flushed to the output buffer and the output is aligned on a byte boundary, so
282: that the decompressor can get all input data available so far. (In
283: particular avail_in is zero after the call if enough output space has been
284: provided before the call.) Flushing may degrade compression for some
285: compression algorithms and so it should be used only when necessary. This
286: completes the current deflate block and follows it with an empty stored block
287: that is three bits plus filler bits to the next byte, followed by four bytes
288: (00 00 ff ff).
289:
290: If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
291: output buffer, but the output is not aligned to a byte boundary. All of the
292: input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
293: This completes the current deflate block and follows it with an empty fixed
294: codes block that is 10 bits long. This assures that enough bytes are output
295: in order for the decompressor to finish the block before the empty fixed code
296: block.
297:
298: If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
299: for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
300: seven bits of the current block are held to be written as the next byte after
301: the next deflate block is completed. In this case, the decompressor may not
302: be provided enough bits at this point in order to complete decompression of
303: the data provided so far to the compressor. It may need to wait for the next
304: block to be emitted. This is for advanced applications that need to control
305: the emission of deflate blocks.
306:
307: If flush is set to Z_FULL_FLUSH, all output is flushed as with
308: Z_SYNC_FLUSH, and the compression state is reset so that decompression can
309: restart from this point if previous compressed data has been damaged or if
310: random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
311: compression.
312:
313: If deflate returns with avail_out == 0, this function must be called again
314: with the same value of the flush parameter and more output space (updated
315: avail_out), until the flush is complete (deflate returns with non-zero
316: avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
317: avail_out is greater than six to avoid repeated flush markers due to
318: avail_out == 0 on return.
319:
320: If the parameter flush is set to Z_FINISH, pending input is processed,
321: pending output is flushed and deflate returns with Z_STREAM_END if there was
322: enough output space; if deflate returns with Z_OK, this function must be
323: called again with Z_FINISH and more output space (updated avail_out) but no
324: more input data, until it returns with Z_STREAM_END or an error. After
325: deflate has returned Z_STREAM_END, the only possible operations on the stream
326: are deflateReset or deflateEnd.
327:
328: Z_FINISH can be used immediately after deflateInit if all the compression
329: is to be done in a single step. In this case, avail_out must be at least the
330: value returned by deflateBound (see below). If deflate does not return
331: Z_STREAM_END, then it must be called again as described above.
332:
333: deflate() sets strm->adler to the adler32 checksum of all input read
334: so far (that is, total_in bytes).
335:
336: deflate() may update strm->data_type if it can make a good guess about
337: the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
338: binary. This field is only for information purposes and does not affect the
339: compression algorithm in any manner.
340:
341: deflate() returns Z_OK if some progress has been made (more input
342: processed or more output produced), Z_STREAM_END if all input has been
343: consumed and all output has been produced (only when flush is set to
344: Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
345: if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible
346: (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
347: fatal, and deflate() can be called again with more input and more output
348: space to continue compressing.
349: */
350:
351:
352: ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
353: /*
354: All dynamically allocated data structures for this stream are freed.
355: This function discards any unprocessed input and does not flush any pending
356: output.
357:
358: deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
359: stream state was inconsistent, Z_DATA_ERROR if the stream was freed
360: prematurely (some input or output was discarded). In the error case, msg
361: may be set but then points to a static string (which must not be
362: deallocated).
363: */
364:
365:
366: /*
367: ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
368:
369: Initializes the internal stream state for decompression. The fields
370: next_in, avail_in, zalloc, zfree and opaque must be initialized before by
371: the caller. If next_in is not Z_NULL and avail_in is large enough (the
372: exact value depends on the compression method), inflateInit determines the
373: compression method from the zlib header and allocates all data structures
374: accordingly; otherwise the allocation will be deferred to the first call of
375: inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
376: use default allocation functions.
377:
378: inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
379: memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
380: version assumed by the caller, or Z_STREAM_ERROR if the parameters are
381: invalid, such as a null pointer to the structure. msg is set to null if
382: there is no error message. inflateInit does not perform any decompression
383: apart from possibly reading the zlib header if present: actual decompression
384: will be done by inflate(). (So next_in and avail_in may be modified, but
385: next_out and avail_out are unused and unchanged.) The current implementation
386: of inflateInit() does not process any header information -- that is deferred
387: until inflate() is called.
388: */
389:
390:
391: ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
392: /*
393: inflate decompresses as much data as possible, and stops when the input
394: buffer becomes empty or the output buffer becomes full. It may introduce
395: some output latency (reading input without producing any output) except when
396: forced to flush.
397:
398: The detailed semantics are as follows. inflate performs one or both of the
399: following actions:
400:
401: - Decompress more input starting at next_in and update next_in and avail_in
402: accordingly. If not all input can be processed (because there is not
403: enough room in the output buffer), next_in is updated and processing will
404: resume at this point for the next call of inflate().
405:
406: - Provide more output starting at next_out and update next_out and avail_out
407: accordingly. inflate() provides as much output as possible, until there is
408: no more input data or no more space in the output buffer (see below about
409: the flush parameter).
410:
411: Before the call of inflate(), the application should ensure that at least
412: one of the actions is possible, by providing more input and/or consuming more
413: output, and updating the next_* and avail_* values accordingly. The
414: application can consume the uncompressed output when it wants, for example
415: when the output buffer is full (avail_out == 0), or after each call of
416: inflate(). If inflate returns Z_OK and with zero avail_out, it must be
417: called again after making room in the output buffer because there might be
418: more output pending.
419:
420: The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
421: Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
422: output as possible to the output buffer. Z_BLOCK requests that inflate()
423: stop if and when it gets to the next deflate block boundary. When decoding
424: the zlib or gzip format, this will cause inflate() to return immediately
425: after the header and before the first block. When doing a raw inflate,
426: inflate() will go ahead and process the first block, and will return when it
427: gets to the end of that block, or when it runs out of data.
428:
429: The Z_BLOCK option assists in appending to or combining deflate streams.
430: Also to assist in this, on return inflate() will set strm->data_type to the
431: number of unused bits in the last byte taken from strm->next_in, plus 64 if
432: inflate() is currently decoding the last block in the deflate stream, plus
433: 128 if inflate() returned immediately after decoding an end-of-block code or
434: decoding the complete header up to just before the first byte of the deflate
435: stream. The end-of-block will not be indicated until all of the uncompressed
436: data from that block has been written to strm->next_out. The number of
437: unused bits may in general be greater than seven, except when bit 7 of
438: data_type is set, in which case the number of unused bits will be less than
439: eight. data_type is set as noted here every time inflate() returns for all
440: flush options, and so can be used to determine the amount of currently
441: consumed input in bits.
442:
443: The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
444: end of each deflate block header is reached, before any actual data in that
445: block is decoded. This allows the caller to determine the length of the
446: deflate block header for later use in random access within a deflate block.
447: 256 is added to the value of strm->data_type when inflate() returns
448: immediately after reaching the end of the deflate block header.
449:
450: inflate() should normally be called until it returns Z_STREAM_END or an
451: error. However if all decompression is to be performed in a single step (a
452: single call of inflate), the parameter flush should be set to Z_FINISH. In
453: this case all pending input is processed and all pending output is flushed;
454: avail_out must be large enough to hold all the uncompressed data. (The size
455: of the uncompressed data may have been saved by the compressor for this
456: purpose.) The next operation on this stream must be inflateEnd to deallocate
457: the decompression state. The use of Z_FINISH is never required, but can be
458: used to inform inflate that a faster approach may be used for the single
459: inflate() call.
460:
461: In this implementation, inflate() always flushes as much output as
462: possible to the output buffer, and always uses the faster approach on the
463: first call. So the only effect of the flush parameter in this implementation
464: is on the return value of inflate(), as noted below, or when it returns early
465: because Z_BLOCK or Z_TREES is used.
466:
467: If a preset dictionary is needed after this call (see inflateSetDictionary
468: below), inflate sets strm->adler to the adler32 checksum of the dictionary
469: chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
470: strm->adler to the adler32 checksum of all output produced so far (that is,
471: total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
472: below. At the end of the stream, inflate() checks that its computed adler32
473: checksum is equal to that saved by the compressor and returns Z_STREAM_END
474: only if the checksum is correct.
475:
476: inflate() can decompress and check either zlib-wrapped or gzip-wrapped
477: deflate data. The header type is detected automatically, if requested when
478: initializing with inflateInit2(). Any information contained in the gzip
479: header is not retained, so applications that need that information should
480: instead use raw inflate, see inflateInit2() below, or inflateBack() and
481: perform their own processing of the gzip header and trailer.
482:
483: inflate() returns Z_OK if some progress has been made (more input processed
484: or more output produced), Z_STREAM_END if the end of the compressed data has
485: been reached and all uncompressed output has been produced, Z_NEED_DICT if a
486: preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
487: corrupted (input stream not conforming to the zlib format or incorrect check
488: value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
489: next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,
490: Z_BUF_ERROR if no progress is possible or if there was not enough room in the
491: output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
492: inflate() can be called again with more input and more output space to
493: continue decompressing. If Z_DATA_ERROR is returned, the application may
494: then call inflateSync() to look for a good compression block if a partial
495: recovery of the data is desired.
496: */
497:
498:
499: ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
500: /*
501: All dynamically allocated data structures for this stream are freed.
502: This function discards any unprocessed input and does not flush any pending
503: output.
504:
505: inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
506: was inconsistent. In the error case, msg may be set but then points to a
507: static string (which must not be deallocated).
508: */
509:
510:
511: /* Advanced functions */
512:
513: /*
514: The following functions are needed only in some special applications.
515: */
516:
517: /*
518: ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
519: int level,
520: int method,
521: int windowBits,
522: int memLevel,
523: int strategy));
524:
525: This is another version of deflateInit with more compression options. The
526: fields next_in, zalloc, zfree and opaque must be initialized before by the
527: caller.
528:
529: The method parameter is the compression method. It must be Z_DEFLATED in
530: this version of the library.
531:
532: The windowBits parameter is the base two logarithm of the window size
533: (the size of the history buffer). It should be in the range 8..15 for this
534: version of the library. Larger values of this parameter result in better
535: compression at the expense of memory usage. The default value is 15 if
536: deflateInit is used instead.
537:
538: windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
539: determines the window size. deflate() will then generate raw deflate data
540: with no zlib header or trailer, and will not compute an adler32 check value.
541:
542: windowBits can also be greater than 15 for optional gzip encoding. Add
543: 16 to windowBits to write a simple gzip header and trailer around the
544: compressed data instead of a zlib wrapper. The gzip header will have no
545: file name, no extra data, no comment, no modification time (set to zero), no
546: header crc, and the operating system will be set to 255 (unknown). If a
547: gzip stream is being written, strm->adler is a crc32 instead of an adler32.
548:
549: The memLevel parameter specifies how much memory should be allocated
550: for the internal compression state. memLevel=1 uses minimum memory but is
551: slow and reduces compression ratio; memLevel=9 uses maximum memory for
552: optimal speed. The default value is 8. See zconf.h for total memory usage
553: as a function of windowBits and memLevel.
554:
555: The strategy parameter is used to tune the compression algorithm. Use the
556: value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
557: filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
558: string match), or Z_RLE to limit match distances to one (run-length
559: encoding). Filtered data consists mostly of small values with a somewhat
560: random distribution. In this case, the compression algorithm is tuned to
561: compress them better. The effect of Z_FILTERED is to force more Huffman
562: coding and less string matching; it is somewhat intermediate between
563: Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
564: fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
565: strategy parameter only affects the compression ratio but not the
566: correctness of the compressed output even if it is not set appropriately.
567: Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
568: decoder for special applications.
569:
570: deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
571: memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
572: method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
573: incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
574: set to null if there is no error message. deflateInit2 does not perform any
575: compression: this will be done by deflate().
576: */
577:
578: ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
579: const Bytef *dictionary,
580: uInt dictLength));
581: /*
582: Initializes the compression dictionary from the given byte sequence
583: without producing any compressed output. This function must be called
584: immediately after deflateInit, deflateInit2 or deflateReset, before any call
585: of deflate. The compressor and decompressor must use exactly the same
586: dictionary (see inflateSetDictionary).
587:
588: The dictionary should consist of strings (byte sequences) that are likely
589: to be encountered later in the data to be compressed, with the most commonly
590: used strings preferably put towards the end of the dictionary. Using a
591: dictionary is most useful when the data to be compressed is short and can be
592: predicted with good accuracy; the data can then be compressed better than
593: with the default empty dictionary.
594:
595: Depending on the size of the compression data structures selected by
596: deflateInit or deflateInit2, a part of the dictionary may in effect be
597: discarded, for example if the dictionary is larger than the window size
598: provided in deflateInit or deflateInit2. Thus the strings most likely to be
599: useful should be put at the end of the dictionary, not at the front. In
600: addition, the current implementation of deflate will use at most the window
601: size minus 262 bytes of the provided dictionary.
602:
603: Upon return of this function, strm->adler is set to the adler32 value
604: of the dictionary; the decompressor may later use this value to determine
605: which dictionary has been used by the compressor. (The adler32 value
606: applies to the whole dictionary even if only a subset of the dictionary is
607: actually used by the compressor.) If a raw deflate was requested, then the
608: adler32 value is not computed and strm->adler is not set.
609:
610: deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
611: parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
612: inconsistent (for example if deflate has already been called for this stream
613: or if the compression method is bsort). deflateSetDictionary does not
614: perform any compression: this will be done by deflate().
615: */
616:
617: ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
618: z_streamp source));
619: /*
620: Sets the destination stream as a complete copy of the source stream.
621:
622: This function can be useful when several compression strategies will be
623: tried, for example when there are several ways of pre-processing the input
624: data with a filter. The streams that will be discarded should then be freed
625: by calling deflateEnd. Note that deflateCopy duplicates the internal
626: compression state which can be quite large, so this strategy is slow and can
627: consume lots of memory.
628:
629: deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
630: enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
631: (such as zalloc being Z_NULL). msg is left unchanged in both source and
632: destination.
633: */
634:
635: ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
636: /*
637: This function is equivalent to deflateEnd followed by deflateInit,
638: but does not free and reallocate all the internal compression state. The
639: stream will keep the same compression level and any other attributes that
640: may have been set by deflateInit2.
641:
642: deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
643: stream state was inconsistent (such as zalloc or state being Z_NULL).
644: */
645:
646: ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
647: int level,
648: int strategy));
649: /*
650: Dynamically update the compression level and compression strategy. The
651: interpretation of level and strategy is as in deflateInit2. This can be
652: used to switch between compression and straight copy of the input data, or
653: to switch to a different kind of input data requiring a different strategy.
654: If the compression level is changed, the input available so far is
655: compressed with the old level (and may be flushed); the new level will take
656: effect only at the next call of deflate().
657:
658: Before the call of deflateParams, the stream state must be set as for
659: a call of deflate(), since the currently available input may have to be
660: compressed and flushed. In particular, strm->avail_out must be non-zero.
661:
662: deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
663: stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if
664: strm->avail_out was zero.
665: */
666:
667: ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
668: int good_length,
669: int max_lazy,
670: int nice_length,
671: int max_chain));
672: /*
673: Fine tune deflate's internal compression parameters. This should only be
674: used by someone who understands the algorithm used by zlib's deflate for
675: searching for the best matching string, and even then only by the most
676: fanatic optimizer trying to squeeze out the last compressed bit for their
677: specific input data. Read the deflate.c source code for the meaning of the
678: max_lazy, good_length, nice_length, and max_chain parameters.
679:
680: deflateTune() can be called after deflateInit() or deflateInit2(), and
681: returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
682: */
683:
684: ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
685: uLong sourceLen));
686: /*
687: deflateBound() returns an upper bound on the compressed size after
688: deflation of sourceLen bytes. It must be called after deflateInit() or
689: deflateInit2(), and after deflateSetHeader(), if used. This would be used
690: to allocate an output buffer for deflation in a single pass, and so would be
691: called before deflate().
692: */
693:
694: ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
695: int bits,
696: int value));
697: /*
698: deflatePrime() inserts bits in the deflate output stream. The intent
699: is that this function is used to start off the deflate output with the bits
700: leftover from a previous deflate stream when appending to it. As such, this
701: function can only be used for raw deflate, and must be used before the first
702: deflate() call after a deflateInit2() or deflateReset(). bits must be less
703: than or equal to 16, and that many of the least significant bits of value
704: will be inserted in the output.
705:
706: deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
707: stream state was inconsistent.
708: */
709:
710: ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
711: gz_headerp head));
712: /*
713: deflateSetHeader() provides gzip header information for when a gzip
714: stream is requested by deflateInit2(). deflateSetHeader() may be called
715: after deflateInit2() or deflateReset() and before the first call of
716: deflate(). The text, time, os, extra field, name, and comment information
717: in the provided gz_header structure are written to the gzip header (xflag is
718: ignored -- the extra flags are set according to the compression level). The
719: caller must assure that, if not Z_NULL, name and comment are terminated with
720: a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
721: available there. If hcrc is true, a gzip header crc is included. Note that
722: the current versions of the command-line version of gzip (up through version
723: 1.3.x) do not support header crc's, and will report that it is a "multi-part
724: gzip file" and give up.
725:
726: If deflateSetHeader is not used, the default gzip header has text false,
727: the time set to zero, and os set to 255, with no extra, name, or comment
728: fields. The gzip header is returned to the default state by deflateReset().
729:
730: deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
731: stream state was inconsistent.
732: */
733:
734: /*
735: ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
736: int windowBits));
737:
738: This is another version of inflateInit with an extra parameter. The
739: fields next_in, avail_in, zalloc, zfree and opaque must be initialized
740: before by the caller.
741:
742: The windowBits parameter is the base two logarithm of the maximum window
743: size (the size of the history buffer). It should be in the range 8..15 for
744: this version of the library. The default value is 15 if inflateInit is used
745: instead. windowBits must be greater than or equal to the windowBits value
746: provided to deflateInit2() while compressing, or it must be equal to 15 if
747: deflateInit2() was not used. If a compressed stream with a larger window
748: size is given as input, inflate() will return with the error code
749: Z_DATA_ERROR instead of trying to allocate a larger window.
750:
751: windowBits can also be zero to request that inflate use the window size in
752: the zlib header of the compressed stream.
753:
754: windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
755: determines the window size. inflate() will then process raw deflate data,
756: not looking for a zlib or gzip header, not generating a check value, and not
757: looking for any check values for comparison at the end of the stream. This
758: is for use with other formats that use the deflate compressed data format
759: such as zip. Those formats provide their own check values. If a custom
760: format is developed using the raw deflate format for compressed data, it is
761: recommended that a check value such as an adler32 or a crc32 be applied to
762: the uncompressed data as is done in the zlib, gzip, and zip formats. For
763: most applications, the zlib format should be used as is. Note that comments
764: above on the use in deflateInit2() applies to the magnitude of windowBits.
765:
766: windowBits can also be greater than 15 for optional gzip decoding. Add
767: 32 to windowBits to enable zlib and gzip decoding with automatic header
768: detection, or add 16 to decode only the gzip format (the zlib format will
769: return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
770: crc32 instead of an adler32.
771:
772: inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
773: memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
774: version assumed by the caller, or Z_STREAM_ERROR if the parameters are
775: invalid, such as a null pointer to the structure. msg is set to null if
776: there is no error message. inflateInit2 does not perform any decompression
777: apart from possibly reading the zlib header if present: actual decompression
778: will be done by inflate(). (So next_in and avail_in may be modified, but
779: next_out and avail_out are unused and unchanged.) The current implementation
780: of inflateInit2() does not process any header information -- that is
781: deferred until inflate() is called.
782: */
783:
784: ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
785: const Bytef *dictionary,
786: uInt dictLength));
787: /*
788: Initializes the decompression dictionary from the given uncompressed byte
789: sequence. This function must be called immediately after a call of inflate,
790: if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
791: can be determined from the adler32 value returned by that call of inflate.
792: The compressor and decompressor must use exactly the same dictionary (see
793: deflateSetDictionary). For raw inflate, this function can be called
794: immediately after inflateInit2() or inflateReset() and before any call of
795: inflate() to set the dictionary. The application must insure that the
796: dictionary that was used for compression is provided.
797:
798: inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
799: parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
800: inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
801: expected one (incorrect adler32 value). inflateSetDictionary does not
802: perform any decompression: this will be done by subsequent calls of
803: inflate().
804: */
805:
806: ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
807: /*
808: Skips invalid compressed data until a full flush point (see above the
809: description of deflate with Z_FULL_FLUSH) can be found, or until all
810: available input is skipped. No output is provided.
811:
812: inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
813: if no more input was provided, Z_DATA_ERROR if no flush point has been
814: found, or Z_STREAM_ERROR if the stream structure was inconsistent. In the
815: success case, the application may save the current current value of total_in
816: which indicates where valid compressed data was found. In the error case,
817: the application may repeatedly call inflateSync, providing more input each
818: time, until success or end of the input data.
819: */
820:
821: ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
822: z_streamp source));
823: /*
824: Sets the destination stream as a complete copy of the source stream.
825:
826: This function can be useful when randomly accessing a large stream. The
827: first pass through the stream can periodically record the inflate state,
828: allowing restarting inflate at those points when randomly accessing the
829: stream.
830:
831: inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
832: enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
833: (such as zalloc being Z_NULL). msg is left unchanged in both source and
834: destination.
835: */
836:
837: ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
838: /*
839: This function is equivalent to inflateEnd followed by inflateInit,
840: but does not free and reallocate all the internal decompression state. The
841: stream will keep attributes that may have been set by inflateInit2.
842:
843: inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
844: stream state was inconsistent (such as zalloc or state being Z_NULL).
845: */
846:
847: ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
848: int windowBits));
849: /*
850: This function is the same as inflateReset, but it also permits changing
851: the wrap and window size requests. The windowBits parameter is interpreted
852: the same as it is for inflateInit2.
853:
854: inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
855: stream state was inconsistent (such as zalloc or state being Z_NULL), or if
856: the windowBits parameter is invalid.
857: */
858:
859: ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
860: int bits,
861: int value));
862: /*
863: This function inserts bits in the inflate input stream. The intent is
864: that this function is used to start inflating at a bit position in the
865: middle of a byte. The provided bits will be used before any bytes are used
866: from next_in. This function should only be used with raw inflate, and
867: should be used before the first inflate() call after inflateInit2() or
868: inflateReset(). bits must be less than or equal to 16, and that many of the
869: least significant bits of value will be inserted in the input.
870:
871: If bits is negative, then the input stream bit buffer is emptied. Then
872: inflatePrime() can be called again to put bits in the buffer. This is used
873: to clear out bits leftover after feeding inflate a block description prior
874: to feeding inflate codes.
875:
876: inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
877: stream state was inconsistent.
878: */
879:
880: ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
881: /*
882: This function returns two values, one in the lower 16 bits of the return
883: value, and the other in the remaining upper bits, obtained by shifting the
884: return value down 16 bits. If the upper value is -1 and the lower value is
885: zero, then inflate() is currently decoding information outside of a block.
886: If the upper value is -1 and the lower value is non-zero, then inflate is in
887: the middle of a stored block, with the lower value equaling the number of
888: bytes from the input remaining to copy. If the upper value is not -1, then
889: it is the number of bits back from the current bit position in the input of
890: the code (literal or length/distance pair) currently being processed. In
891: that case the lower value is the number of bytes already emitted for that
892: code.
893:
894: A code is being processed if inflate is waiting for more input to complete
895: decoding of the code, or if it has completed decoding but is waiting for
896: more output space to write the literal or match data.
897:
898: inflateMark() is used to mark locations in the input data for random
899: access, which may be at bit positions, and to note those cases where the
900: output of a code may span boundaries of random access blocks. The current
901: location in the input stream can be determined from avail_in and data_type
902: as noted in the description for the Z_BLOCK flush parameter for inflate.
903:
904: inflateMark returns the value noted above or -1 << 16 if the provided
905: source stream state was inconsistent.
906: */
907:
908: ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
909: gz_headerp head));
910: /*
911: inflateGetHeader() requests that gzip header information be stored in the
912: provided gz_header structure. inflateGetHeader() may be called after
913: inflateInit2() or inflateReset(), and before the first call of inflate().
914: As inflate() processes the gzip stream, head->done is zero until the header
915: is completed, at which time head->done is set to one. If a zlib stream is
916: being decoded, then head->done is set to -1 to indicate that there will be
917: no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
918: used to force inflate() to return immediately after header processing is
919: complete and before any actual data is decompressed.
920:
921: The text, time, xflags, and os fields are filled in with the gzip header
922: contents. hcrc is set to true if there is a header CRC. (The header CRC
923: was valid if done is set to one.) If extra is not Z_NULL, then extra_max
924: contains the maximum number of bytes to write to extra. Once done is true,
925: extra_len contains the actual extra field length, and extra contains the
926: extra field, or that field truncated if extra_max is less than extra_len.
927: If name is not Z_NULL, then up to name_max characters are written there,
928: terminated with a zero unless the length is greater than name_max. If
929: comment is not Z_NULL, then up to comm_max characters are written there,
930: terminated with a zero unless the length is greater than comm_max. When any
931: of extra, name, or comment are not Z_NULL and the respective field is not
932: present in the header, then that field is set to Z_NULL to signal its
933: absence. This allows the use of deflateSetHeader() with the returned
934: structure to duplicate the header. However if those fields are set to
935: allocated memory, then the application will need to save those pointers
936: elsewhere so that they can be eventually freed.
937:
938: If inflateGetHeader is not used, then the header information is simply
939: discarded. The header is always checked for validity, including the header
940: CRC if present. inflateReset() will reset the process to discard the header
941: information. The application would need to call inflateGetHeader() again to
942: retrieve the header from the next gzip stream.
943:
944: inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
945: stream state was inconsistent.
946: */
947:
948: /*
949: ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
950: unsigned char FAR *window));
951:
952: Initialize the internal stream state for decompression using inflateBack()
953: calls. The fields zalloc, zfree and opaque in strm must be initialized
954: before the call. If zalloc and zfree are Z_NULL, then the default library-
955: derived memory allocation routines are used. windowBits is the base two
956: logarithm of the window size, in the range 8..15. window is a caller
957: supplied buffer of that size. Except for special applications where it is
958: assured that deflate was used with small window sizes, windowBits must be 15
959: and a 32K byte window must be supplied to be able to decompress general
960: deflate streams.
961:
962: See inflateBack() for the usage of these routines.
963:
964: inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
965: the paramaters are invalid, Z_MEM_ERROR if the internal state could not be
966: allocated, or Z_VERSION_ERROR if the version of the library does not match
967: the version of the header file.
968: */
969:
970: typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *));
971: typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
972:
973: ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
974: in_func in, void FAR *in_desc,
975: out_func out, void FAR *out_desc));
976: /*
977: inflateBack() does a raw inflate with a single call using a call-back
978: interface for input and output. This is more efficient than inflate() for
979: file i/o applications in that it avoids copying between the output and the
980: sliding window by simply making the window itself the output buffer. This
981: function trusts the application to not change the output buffer passed by
982: the output function, at least until inflateBack() returns.
983:
984: inflateBackInit() must be called first to allocate the internal state
985: and to initialize the state with the user-provided window buffer.
986: inflateBack() may then be used multiple times to inflate a complete, raw
987: deflate stream with each call. inflateBackEnd() is then called to free the
988: allocated state.
989:
990: A raw deflate stream is one with no zlib or gzip header or trailer.
991: This routine would normally be used in a utility that reads zip or gzip
992: files and writes out uncompressed files. The utility would decode the
993: header and process the trailer on its own, hence this routine expects only
994: the raw deflate stream to decompress. This is different from the normal
995: behavior of inflate(), which expects either a zlib or gzip header and
996: trailer around the deflate stream.
997:
998: inflateBack() uses two subroutines supplied by the caller that are then
999: called by inflateBack() for input and output. inflateBack() calls those
1000: routines until it reads a complete deflate stream and writes out all of the
1001: uncompressed data, or until it encounters an error. The function's
1002: parameters and return types are defined above in the in_func and out_func
1003: typedefs. inflateBack() will call in(in_desc, &buf) which should return the
1004: number of bytes of provided input, and a pointer to that input in buf. If
1005: there is no input available, in() must return zero--buf is ignored in that
1006: case--and inflateBack() will return a buffer error. inflateBack() will call
1007: out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()
1008: should return zero on success, or non-zero on failure. If out() returns
1009: non-zero, inflateBack() will return with an error. Neither in() nor out()
1010: are permitted to change the contents of the window provided to
1011: inflateBackInit(), which is also the buffer that out() uses to write from.
1012: The length written by out() will be at most the window size. Any non-zero
1013: amount of input may be provided by in().
1014:
1015: For convenience, inflateBack() can be provided input on the first call by
1016: setting strm->next_in and strm->avail_in. If that input is exhausted, then
1017: in() will be called. Therefore strm->next_in must be initialized before
1018: calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
1019: immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
1020: must also be initialized, and then if strm->avail_in is not zero, input will
1021: initially be taken from strm->next_in[0 .. strm->avail_in - 1].
1022:
1023: The in_desc and out_desc parameters of inflateBack() is passed as the
1024: first parameter of in() and out() respectively when they are called. These
1025: descriptors can be optionally used to pass any information that the caller-
1026: supplied in() and out() functions need to do their job.
1027:
1028: On return, inflateBack() will set strm->next_in and strm->avail_in to
1029: pass back any unused input that was provided by the last in() call. The
1030: return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1031: if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1032: in the deflate stream (in which case strm->msg is set to indicate the nature
1033: of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1034: In the case of Z_BUF_ERROR, an input or output error can be distinguished
1035: using strm->next_in which will be Z_NULL only if in() returned an error. If
1036: strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1037: non-zero. (in() will always be called before out(), so strm->next_in is
1038: assured to be defined if out() returns non-zero.) Note that inflateBack()
1039: cannot return Z_OK.
1040: */
1041:
1042: ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
1043: /*
1044: All memory allocated by inflateBackInit() is freed.
1045:
1046: inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1047: state was inconsistent.
1048: */
1049:
1050: ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
1051: /* Return flags indicating compile-time options.
1052:
1053: Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1054: 1.0: size of uInt
1055: 3.2: size of uLong
1056: 5.4: size of voidpf (pointer)
1057: 7.6: size of z_off_t
1058:
1059: Compiler, assembler, and debug options:
1060: 8: DEBUG
1061: 9: ASMV or ASMINF -- use ASM code
1062: 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1063: 11: 0 (reserved)
1064:
1065: One-time table building (smaller code, but not thread-safe if true):
1066: 12: BUILDFIXED -- build static block decoding tables when needed
1067: 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1068: 14,15: 0 (reserved)
1069:
1070: Library content (indicates missing functionality):
1071: 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1072: deflate code when not needed)
1073: 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1074: and decode gzip streams (to avoid linking crc code)
1075: 18-19: 0 (reserved)
1076:
1077: Operation variations (changes in library functionality):
1078: 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1079: 21: FASTEST -- deflate algorithm with only one, lowest compression level
1080: 22,23: 0 (reserved)
1081:
1082: The sprintf variant used by gzprintf (zero is best):
1083: 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1084: 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1085: 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1086:
1087: Remainder:
1088: 27-31: 0 (reserved)
1089: */
1090:
1091:
1092: /* utility functions */
1093:
1094: /*
1095: The following utility functions are implemented on top of the basic
1096: stream-oriented functions. To simplify the interface, some default options
1097: are assumed (compression level and memory usage, standard memory allocation
1098: functions). The source code of these utility functions can be modified if
1099: you need special options.
1100: */
1101:
1102: ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
1103: const Bytef *source, uLong sourceLen));
1104: /*
1105: Compresses the source buffer into the destination buffer. sourceLen is
1106: the byte length of the source buffer. Upon entry, destLen is the total size
1107: of the destination buffer, which must be at least the value returned by
1108: compressBound(sourceLen). Upon exit, destLen is the actual size of the
1109: compressed buffer.
1110:
1111: compress returns Z_OK if success, Z_MEM_ERROR if there was not
1112: enough memory, Z_BUF_ERROR if there was not enough room in the output
1113: buffer.
1114: */
1115:
1116: ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
1117: const Bytef *source, uLong sourceLen,
1118: int level));
1119: /*
1120: Compresses the source buffer into the destination buffer. The level
1121: parameter has the same meaning as in deflateInit. sourceLen is the byte
1122: length of the source buffer. Upon entry, destLen is the total size of the
1123: destination buffer, which must be at least the value returned by
1124: compressBound(sourceLen). Upon exit, destLen is the actual size of the
1125: compressed buffer.
1126:
1127: compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1128: memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1129: Z_STREAM_ERROR if the level parameter is invalid.
1130: */
1131:
1132: ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
1133: /*
1134: compressBound() returns an upper bound on the compressed size after
1135: compress() or compress2() on sourceLen bytes. It would be used before a
1136: compress() or compress2() call to allocate the destination buffer.
1137: */
1138:
1139: ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
1140: const Bytef *source, uLong sourceLen));
1141: /*
1142: Decompresses the source buffer into the destination buffer. sourceLen is
1143: the byte length of the source buffer. Upon entry, destLen is the total size
1144: of the destination buffer, which must be large enough to hold the entire
1145: uncompressed data. (The size of the uncompressed data must have been saved
1146: previously by the compressor and transmitted to the decompressor by some
1147: mechanism outside the scope of this compression library.) Upon exit, destLen
1148: is the actual size of the uncompressed buffer.
1149:
1150: uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1151: enough memory, Z_BUF_ERROR if there was not enough room in the output
1152: buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.
1153: */
1154:
1155:
1156: /* gzip file access functions */
1157:
1158: /*
1159: This library supports reading and writing files in gzip (.gz) format with
1160: an interface similar to that of stdio, using the functions that start with
1161: "gz". The gzip format is different from the zlib format. gzip is a gzip
1162: wrapper, documented in RFC 1952, wrapped around a deflate stream.
1163: */
1164:
1165: typedef voidp gzFile; /* opaque gzip file descriptor */
1166:
1167: /*
1168: ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1169:
1170: Opens a gzip (.gz) file for reading or writing. The mode parameter is as
1171: in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
1172: a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
1173: compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
1174: for fixed code compression as in "wb9F". (See the description of
1175: deflateInit2 for more information about the strategy parameter.) Also "a"
1176: can be used instead of "w" to request that the gzip stream that will be
1177: written be appended to the file. "+" will result in an error, since reading
1178: and writing to the same gzip file is not supported.
1179:
1180: gzopen can be used to read a file which is not in gzip format; in this
1181: case gzread will directly read from the file without decompression.
1182:
1183: gzopen returns NULL if the file could not be opened, if there was
1184: insufficient memory to allocate the gzFile state, or if an invalid mode was
1185: specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1186: errno can be checked to determine if the reason gzopen failed was that the
1187: file could not be opened.
1188: */
1189:
1190: ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
1191: /*
1192: gzdopen associates a gzFile with the file descriptor fd. File descriptors
1193: are obtained from calls like open, dup, creat, pipe or fileno (if the file
1194: has been previously opened with fopen). The mode parameter is as in gzopen.
1195:
1196: The next call of gzclose on the returned gzFile will also close the file
1197: descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1198: fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1199: mode);. The duplicated descriptor should be saved to avoid a leak, since
1200: gzdopen does not close fd if it fails.
1201:
1202: gzdopen returns NULL if there was insufficient memory to allocate the
1203: gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1204: provided, or '+' was provided), or if fd is -1. The file descriptor is not
1205: used until the next gz* read, write, seek, or close operation, so gzdopen
1206: will not detect if fd is invalid (unless fd is -1).
1207: */
1208:
1209: ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
1210: /*
1211: Set the internal buffer size used by this library's functions. The
1212: default buffer size is 8192 bytes. This function must be called after
1213: gzopen() or gzdopen(), and before any other calls that read or write the
1214: file. The buffer memory allocation is always deferred to the first read or
1215: write. Two buffers are allocated, either both of the specified size when
1216: writing, or one of the specified size and the other twice that size when
1217: reading. A larger buffer size of, for example, 64K or 128K bytes will
1218: noticeably increase the speed of decompression (reading).
1219:
1220: The new buffer size also affects the maximum length for gzprintf().
1221:
1222: gzbuffer() returns 0 on success, or -1 on failure, such as being called
1223: too late.
1224: */
1225:
1226: ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1227: /*
1228: Dynamically update the compression level or strategy. See the description
1229: of deflateInit2 for the meaning of these parameters.
1230:
1231: gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
1232: opened for writing.
1233: */
1234:
1235: ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1236: /*
1237: Reads the given number of uncompressed bytes from the compressed file. If
1238: the input file was not in gzip format, gzread copies the given number of
1239: bytes into the buffer.
1240:
1241: After reaching the end of a gzip stream in the input, gzread will continue
1242: to read, looking for another gzip stream, or failing that, reading the rest
1243: of the input file directly without decompression. The entire input file
1244: will be read if gzread is called until it returns less than the requested
1245: len.
1246:
1247: gzread returns the number of uncompressed bytes actually read, less than
1248: len for end of file, or -1 for error.
1249: */
1250:
1251: ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
1252: voidpc buf, unsigned len));
1253: /*
1254: Writes the given number of uncompressed bytes into the compressed file.
1255: gzwrite returns the number of uncompressed bytes written or 0 in case of
1256: error.
1257: */
1258:
1259: ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...));
1260: /*
1261: Converts, formats, and writes the arguments to the compressed file under
1262: control of the format string, as in fprintf. gzprintf returns the number of
1263: uncompressed bytes actually written, or 0 in case of error. The number of
1264: uncompressed bytes written is limited to 8191, or one less than the buffer
1265: size given to gzbuffer(). The caller should assure that this limit is not
1266: exceeded. If it is exceeded, then gzprintf() will return an error (0) with
1267: nothing written. In this case, there may also be a buffer overflow with
1268: unpredictable consequences, which is possible only if zlib was compiled with
1269: the insecure functions sprintf() or vsprintf() because the secure snprintf()
1270: or vsnprintf() functions were not available. This can be determined using
1271: zlibCompileFlags().
1272: */
1273:
1274: ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
1275: /*
1276: Writes the given null-terminated string to the compressed file, excluding
1277: the terminating null character.
1278:
1279: gzputs returns the number of characters written, or -1 in case of error.
1280: */
1281:
1282: ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
1283: /*
1284: Reads bytes from the compressed file until len-1 characters are read, or a
1285: newline character is read and transferred to buf, or an end-of-file
1286: condition is encountered. If any characters are read or if len == 1, the
1287: string is terminated with a null character. If no characters are read due
1288: to an end-of-file or len < 1, then the buffer is left untouched.
1289:
1290: gzgets returns buf which is a null-terminated string, or it returns NULL
1291: for end-of-file or in case of error. If there was an error, the contents at
1292: buf are indeterminate.
1293: */
1294:
1295: ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1296: /*
1297: Writes c, converted to an unsigned char, into the compressed file. gzputc
1298: returns the value that was written, or -1 in case of error.
1299: */
1300:
1301: ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1302: /*
1303: Reads one byte from the compressed file. gzgetc returns this byte or -1
1304: in case of end of file or error.
1305: */
1306:
1307: ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1308: /*
1309: Push one character back onto the stream to be read as the first character
1310: on the next read. At least one character of push-back is allowed.
1311: gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1312: fail if c is -1, and may fail if a character has been pushed but not read
1313: yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
1314: output buffer size of pushed characters is allowed. (See gzbuffer above.)
1315: The pushed character will be discarded if the stream is repositioned with
1316: gzseek() or gzrewind().
1317: */
1318:
1319: ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1320: /*
1321: Flushes all pending output into the compressed file. The parameter flush
1322: is as in the deflate() function. The return value is the zlib error number
1323: (see function gzerror below). gzflush is only permitted when writing.
1324:
1325: If the flush parameter is Z_FINISH, the remaining data is written and the
1326: gzip stream is completed in the output. If gzwrite() is called again, a new
1327: gzip stream will be started in the output. gzread() is able to read such
1328: concatented gzip streams.
1329:
1330: gzflush should be called only when strictly necessary because it will
1331: degrade compression if called too often.
1332: */
1333:
1334: /*
1335: ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1336: z_off_t offset, int whence));
1337:
1338: Sets the starting position for the next gzread or gzwrite on the given
1339: compressed file. The offset represents a number of bytes in the
1340: uncompressed data stream. The whence parameter is defined as in lseek(2);
1341: the value SEEK_END is not supported.
1342:
1343: If the file is opened for reading, this function is emulated but can be
1344: extremely slow. If the file is opened for writing, only forward seeks are
1345: supported; gzseek then compresses a sequence of zeroes up to the new
1346: starting position.
1347:
1348: gzseek returns the resulting offset location as measured in bytes from
1349: the beginning of the uncompressed stream, or -1 in case of error, in
1350: particular if the file is opened for writing and the new starting position
1351: would be before the current position.
1352: */
1353:
1354: ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
1355: /*
1356: Rewinds the given file. This function is supported only for reading.
1357:
1358: gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1359: */
1360:
1361: /*
1362: ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
1363:
1364: Returns the starting position for the next gzread or gzwrite on the given
1365: compressed file. This position represents a number of bytes in the
1366: uncompressed data stream, and is zero when starting, even if appending or
1367: reading a gzip stream from the middle of a file using gzdopen().
1368:
1369: gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1370: */
1371:
1372: /*
1373: ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
1374:
1375: Returns the current offset in the file being read or written. This offset
1376: includes the count of bytes that precede the gzip stream, for example when
1377: appending or when using gzdopen() for reading. When reading, the offset
1378: does not include as yet unused buffered input. This information can be used
1379: for a progress indicator. On error, gzoffset() returns -1.
1380: */
1381:
1382: ZEXTERN int ZEXPORT gzeof OF((gzFile file));
1383: /*
1384: Returns true (1) if the end-of-file indicator has been set while reading,
1385: false (0) otherwise. Note that the end-of-file indicator is set only if the
1386: read tried to go past the end of the input, but came up short. Therefore,
1387: just like feof(), gzeof() may return false even if there is no more data to
1388: read, in the event that the last read request was for the exact number of
1389: bytes remaining in the input file. This will happen if the input file size
1390: is an exact multiple of the buffer size.
1391:
1392: If gzeof() returns true, then the read functions will return no more data,
1393: unless the end-of-file indicator is reset by gzclearerr() and the input file
1394: has grown since the previous end of file was detected.
1395: */
1396:
1397: ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
1398: /*
1399: Returns true (1) if file is being copied directly while reading, or false
1400: (0) if file is a gzip stream being decompressed. This state can change from
1401: false to true while reading the input file if the end of a gzip stream is
1402: reached, but is followed by data that is not another gzip stream.
1403:
1404: If the input file is empty, gzdirect() will return true, since the input
1405: does not contain a gzip stream.
1406:
1407: If gzdirect() is used immediately after gzopen() or gzdopen() it will
1408: cause buffers to be allocated to allow reading the file to determine if it
1409: is a gzip file. Therefore if gzbuffer() is used, it should be called before
1410: gzdirect().
1411: */
1412:
1413: ZEXTERN int ZEXPORT gzclose OF((gzFile file));
1414: /*
1415: Flushes all pending output if necessary, closes the compressed file and
1416: deallocates the (de)compression state. Note that once file is closed, you
1417: cannot call gzerror with file, since its structures have been deallocated.
1418: gzclose must not be called more than once on the same file, just as free
1419: must not be called more than once on the same allocation.
1420:
1421: gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1422: file operation error, or Z_OK on success.
1423: */
1424:
1425: ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
1426: ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
1427: /*
1428: Same as gzclose(), but gzclose_r() is only for use when reading, and
1429: gzclose_w() is only for use when writing or appending. The advantage to
1430: using these instead of gzclose() is that they avoid linking in zlib
1431: compression or decompression code that is not used when only reading or only
1432: writing respectively. If gzclose() is used, then both compression and
1433: decompression code will be included the application when linking to a static
1434: zlib library.
1435: */
1436:
1437: ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
1438: /*
1439: Returns the error message for the last error which occurred on the given
1440: compressed file. errnum is set to zlib error number. If an error occurred
1441: in the file system and not in the compression library, errnum is set to
1442: Z_ERRNO and the application may consult errno to get the exact error code.
1443:
1444: The application must not modify the returned string. Future calls to
1445: this function may invalidate the previously returned string. If file is
1446: closed, then the string previously returned by gzerror will no longer be
1447: available.
1448:
1449: gzerror() should be used to distinguish errors from end-of-file for those
1450: functions above that do not distinguish those cases in their return values.
1451: */
1452:
1453: ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1454: /*
1455: Clears the error and end-of-file flags for file. This is analogous to the
1456: clearerr() function in stdio. This is useful for continuing to read a gzip
1457: file that is being written concurrently.
1458: */
1459:
1460:
1461: /* checksum functions */
1462:
1463: /*
1464: These functions are not related to compression but are exported
1465: anyway because they might be useful in applications using the compression
1466: library.
1467: */
1468:
1469: ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
1470: /*
1471: Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1472: return the updated checksum. If buf is Z_NULL, this function returns the
1473: required initial value for the checksum.
1474:
1475: An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1476: much faster.
1477:
1478: Usage example:
1479:
1480: uLong adler = adler32(0L, Z_NULL, 0);
1481:
1482: while (read_buffer(buffer, length) != EOF) {
1483: adler = adler32(adler, buffer, length);
1484: }
1485: if (adler != original_adler) error();
1486: */
1487:
1488: /*
1489: ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
1490: z_off_t len2));
1491:
1492: Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1493: and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1494: each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1495: seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.
1496: */
1497:
1498: ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
1499: /*
1500: Update a running CRC-32 with the bytes buf[0..len-1] and return the
1501: updated CRC-32. If buf is Z_NULL, this function returns the required
1502: initial value for the for the crc. Pre- and post-conditioning (one's
1503: complement) is performed within this function so it shouldn't be done by the
1504: application.
1505:
1506: Usage example:
1507:
1508: uLong crc = crc32(0L, Z_NULL, 0);
1509:
1510: while (read_buffer(buffer, length) != EOF) {
1511: crc = crc32(crc, buffer, length);
1512: }
1513: if (crc != original_crc) error();
1514: */
1515:
1516: /*
1517: ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1518:
1519: Combine two CRC-32 check values into one. For two sequences of bytes,
1520: seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1521: calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1522: check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1523: len2.
1524: */
1525:
1526:
1527: /* various hacks, don't look :) */
1528:
1529: /* deflateInit and inflateInit are macros to allow checking the zlib version
1530: * and the compiler's view of z_stream:
1531: */
1532: ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1533: const char *version, int stream_size));
1534: ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
1535: const char *version, int stream_size));
1536: ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
1537: int windowBits, int memLevel,
1538: int strategy, const char *version,
1539: int stream_size));
1540: ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
1541: const char *version, int stream_size));
1542: ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
1543: unsigned char FAR *window,
1544: const char *version,
1545: int stream_size));
1546: #define deflateInit(strm, level) \
1547: deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
1548: #define inflateInit(strm) \
1549: inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
1550: #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1551: deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1552: (strategy), ZLIB_VERSION, sizeof(z_stream))
1553: #define inflateInit2(strm, windowBits) \
1554: inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
1555: #define inflateBackInit(strm, windowBits, window) \
1556: inflateBackInit_((strm), (windowBits), (window), \
1557: ZLIB_VERSION, sizeof(z_stream))
1558:
1559: /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1560: * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1561: * both are true, the application gets the *64 functions, and the regular
1562: * functions are changed to 64 bits) -- in case these are set on systems
1563: * without large file support, _LFS64_LARGEFILE must also be true
1564: */
1565: #if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0
1566: ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1567: ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
1568: ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
1569: ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
1570: ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
1571: ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
1572: #endif
1573:
1574: #if !defined(ZLIB_INTERNAL) && _FILE_OFFSET_BITS-0 == 64 && _LFS64_LARGEFILE-0
1575: # define gzopen gzopen64
1576: # define gzseek gzseek64
1577: # define gztell gztell64
1578: # define gzoffset gzoffset64
1579: # define adler32_combine adler32_combine64
1580: # define crc32_combine crc32_combine64
1581: # ifdef _LARGEFILE64_SOURCE
1582: ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1583: ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
1584: ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
1585: ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
1586: ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
1587: ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
1588: # endif
1589: #else
1590: ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
1591: ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
1592: ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
1593: ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
1594: ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1595: ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1596: #endif
1597:
1598: /* hack for buggy compilers */
1599: #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
1600: struct internal_state {int dummy;};
1601: #endif
1602:
1603: /* undocumented functions */
1604: ZEXTERN const char * ZEXPORT zError OF((int));
1605: ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));
1606: ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void));
1607: ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int));
1608:
1609: #ifdef __cplusplus
1610: }
1611: #endif
1612:
1613: #endif /* ZLIB_H */
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