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1.8.7
1: /* zlib.h -- interface of the 'zlib' general purpose compression library
2: version 1.2.6, January 29th, 2012
3:
4: Copyright (C) 1995-2012 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://tools.ietf.org/html/rfc1950
28: (zlib format), rfc1951 (deflate format) and rfc1952 (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 "1.2.6"
41: #define ZLIB_VERNUM 0x1260
42: #define ZLIB_VER_MAJOR 1
43: #define ZLIB_VER_MINOR 2
44: #define ZLIB_VER_REVISION 6
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: z_const Bytef *next_in; /* next input byte */
87: uInt avail_in; /* number of bytes available at next_in */
88: uLong total_in; /* total number 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 number of bytes output so far */
93:
94: z_const 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). Then deflate is guaranteed to
331: return Z_STREAM_END. If not enough output space is provided, deflate will
332: not return Z_STREAM_END, and it must be called again as described above.
333:
334: deflate() sets strm->adler to the adler32 checksum of all input read
335: so far (that is, total_in bytes).
336:
337: deflate() may update strm->data_type if it can make a good guess about
338: the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
339: binary. This field is only for information purposes and does not affect the
340: compression algorithm in any manner.
341:
342: deflate() returns Z_OK if some progress has been made (more input
343: processed or more output produced), Z_STREAM_END if all input has been
344: consumed and all output has been produced (only when flush is set to
345: Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
346: if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible
347: (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
348: fatal, and deflate() can be called again with more input and more output
349: space to continue compressing.
350: */
351:
352:
353: ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
354: /*
355: All dynamically allocated data structures for this stream are freed.
356: This function discards any unprocessed input and does not flush any pending
357: output.
358:
359: deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
360: stream state was inconsistent, Z_DATA_ERROR if the stream was freed
361: prematurely (some input or output was discarded). In the error case, msg
362: may be set but then points to a static string (which must not be
363: deallocated).
364: */
365:
366:
367: /*
368: ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
369:
370: Initializes the internal stream state for decompression. The fields
371: next_in, avail_in, zalloc, zfree and opaque must be initialized before by
372: the caller. If next_in is not Z_NULL and avail_in is large enough (the
373: exact value depends on the compression method), inflateInit determines the
374: compression method from the zlib header and allocates all data structures
375: accordingly; otherwise the allocation will be deferred to the first call of
376: inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
377: use default allocation functions.
378:
379: inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
380: memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
381: version assumed by the caller, or Z_STREAM_ERROR if the parameters are
382: invalid, such as a null pointer to the structure. msg is set to null if
383: there is no error message. inflateInit does not perform any decompression
384: apart from possibly reading the zlib header if present: actual decompression
385: will be done by inflate(). (So next_in and avail_in may be modified, but
386: next_out and avail_out are unused and unchanged.) The current implementation
387: of inflateInit() does not process any header information -- that is deferred
388: until inflate() is called.
389: */
390:
391:
392: ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
393: /*
394: inflate decompresses as much data as possible, and stops when the input
395: buffer becomes empty or the output buffer becomes full. It may introduce
396: some output latency (reading input without producing any output) except when
397: forced to flush.
398:
399: The detailed semantics are as follows. inflate performs one or both of the
400: following actions:
401:
402: - Decompress more input starting at next_in and update next_in and avail_in
403: accordingly. If not all input can be processed (because there is not
404: enough room in the output buffer), next_in is updated and processing will
405: resume at this point for the next call of inflate().
406:
407: - Provide more output starting at next_out and update next_out and avail_out
408: accordingly. inflate() provides as much output as possible, until there is
409: no more input data or no more space in the output buffer (see below about
410: the flush parameter).
411:
412: Before the call of inflate(), the application should ensure that at least
413: one of the actions is possible, by providing more input and/or consuming more
414: output, and updating the next_* and avail_* values accordingly. The
415: application can consume the uncompressed output when it wants, for example
416: when the output buffer is full (avail_out == 0), or after each call of
417: inflate(). If inflate returns Z_OK and with zero avail_out, it must be
418: called again after making room in the output buffer because there might be
419: more output pending.
420:
421: The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
422: Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
423: output as possible to the output buffer. Z_BLOCK requests that inflate()
424: stop if and when it gets to the next deflate block boundary. When decoding
425: the zlib or gzip format, this will cause inflate() to return immediately
426: after the header and before the first block. When doing a raw inflate,
427: inflate() will go ahead and process the first block, and will return when it
428: gets to the end of that block, or when it runs out of data.
429:
430: The Z_BLOCK option assists in appending to or combining deflate streams.
431: Also to assist in this, on return inflate() will set strm->data_type to the
432: number of unused bits in the last byte taken from strm->next_in, plus 64 if
433: inflate() is currently decoding the last block in the deflate stream, plus
434: 128 if inflate() returned immediately after decoding an end-of-block code or
435: decoding the complete header up to just before the first byte of the deflate
436: stream. The end-of-block will not be indicated until all of the uncompressed
437: data from that block has been written to strm->next_out. The number of
438: unused bits may in general be greater than seven, except when bit 7 of
439: data_type is set, in which case the number of unused bits will be less than
440: eight. data_type is set as noted here every time inflate() returns for all
441: flush options, and so can be used to determine the amount of currently
442: consumed input in bits.
443:
444: The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
445: end of each deflate block header is reached, before any actual data in that
446: block is decoded. This allows the caller to determine the length of the
447: deflate block header for later use in random access within a deflate block.
448: 256 is added to the value of strm->data_type when inflate() returns
449: immediately after reaching the end of the deflate block header.
450:
451: inflate() should normally be called until it returns Z_STREAM_END or an
452: error. However if all decompression is to be performed in a single step (a
453: single call of inflate), the parameter flush should be set to Z_FINISH. In
454: this case all pending input is processed and all pending output is flushed;
455: avail_out must be large enough to hold all the uncompressed data. (The size
456: of the uncompressed data may have been saved by the compressor for this
457: purpose.) The next operation on this stream must be inflateEnd to deallocate
458: the decompression state. The use of Z_FINISH is not required to perform an
459: inflation in one step. However it may be used to inform inflate that a
460: faster approach can be used for the single inflate() call. Z_FINISH also
461: informs inflate to not maintain a sliding window if the stream completes,
462: which reduces inflate's memory footprint.
463:
464: In this implementation, inflate() always flushes as much output as
465: possible to the output buffer, and always uses the faster approach on the
466: first call. So the effects of the flush parameter in this implementation are
467: on the return value of inflate() as noted below, when inflate() returns early
468: when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
469: memory for a sliding window when Z_FINISH is used.
470:
471: If a preset dictionary is needed after this call (see inflateSetDictionary
472: below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
473: chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
474: strm->adler to the Adler-32 checksum of all output produced so far (that is,
475: total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
476: below. At the end of the stream, inflate() checks that its computed adler32
477: checksum is equal to that saved by the compressor and returns Z_STREAM_END
478: only if the checksum is correct.
479:
480: inflate() can decompress and check either zlib-wrapped or gzip-wrapped
481: deflate data. The header type is detected automatically, if requested when
482: initializing with inflateInit2(). Any information contained in the gzip
483: header is not retained, so applications that need that information should
484: instead use raw inflate, see inflateInit2() below, or inflateBack() and
485: perform their own processing of the gzip header and trailer. When processing
486: gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
487: producted so far. The CRC-32 is checked against the gzip trailer.
488:
489: inflate() returns Z_OK if some progress has been made (more input processed
490: or more output produced), Z_STREAM_END if the end of the compressed data has
491: been reached and all uncompressed output has been produced, Z_NEED_DICT if a
492: preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
493: corrupted (input stream not conforming to the zlib format or incorrect check
494: value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
495: next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,
496: Z_BUF_ERROR if no progress is possible or if there was not enough room in the
497: output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
498: inflate() can be called again with more input and more output space to
499: continue decompressing. If Z_DATA_ERROR is returned, the application may
500: then call inflateSync() to look for a good compression block if a partial
501: recovery of the data is desired.
502: */
503:
504:
505: ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
506: /*
507: All dynamically allocated data structures for this stream are freed.
508: This function discards any unprocessed input and does not flush any pending
509: output.
510:
511: inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
512: was inconsistent. In the error case, msg may be set but then points to a
513: static string (which must not be deallocated).
514: */
515:
516:
517: /* Advanced functions */
518:
519: /*
520: The following functions are needed only in some special applications.
521: */
522:
523: /*
524: ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
525: int level,
526: int method,
527: int windowBits,
528: int memLevel,
529: int strategy));
530:
531: This is another version of deflateInit with more compression options. The
532: fields next_in, zalloc, zfree and opaque must be initialized before by the
533: caller.
534:
535: The method parameter is the compression method. It must be Z_DEFLATED in
536: this version of the library.
537:
538: The windowBits parameter is the base two logarithm of the window size
539: (the size of the history buffer). It should be in the range 8..15 for this
540: version of the library. Larger values of this parameter result in better
541: compression at the expense of memory usage. The default value is 15 if
542: deflateInit is used instead.
543:
544: windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
545: determines the window size. deflate() will then generate raw deflate data
546: with no zlib header or trailer, and will not compute an adler32 check value.
547:
548: windowBits can also be greater than 15 for optional gzip encoding. Add
549: 16 to windowBits to write a simple gzip header and trailer around the
550: compressed data instead of a zlib wrapper. The gzip header will have no
551: file name, no extra data, no comment, no modification time (set to zero), no
552: header crc, and the operating system will be set to 255 (unknown). If a
553: gzip stream is being written, strm->adler is a crc32 instead of an adler32.
554:
555: The memLevel parameter specifies how much memory should be allocated
556: for the internal compression state. memLevel=1 uses minimum memory but is
557: slow and reduces compression ratio; memLevel=9 uses maximum memory for
558: optimal speed. The default value is 8. See zconf.h for total memory usage
559: as a function of windowBits and memLevel.
560:
561: The strategy parameter is used to tune the compression algorithm. Use the
562: value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
563: filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
564: string match), or Z_RLE to limit match distances to one (run-length
565: encoding). Filtered data consists mostly of small values with a somewhat
566: random distribution. In this case, the compression algorithm is tuned to
567: compress them better. The effect of Z_FILTERED is to force more Huffman
568: coding and less string matching; it is somewhat intermediate between
569: Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
570: fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
571: strategy parameter only affects the compression ratio but not the
572: correctness of the compressed output even if it is not set appropriately.
573: Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
574: decoder for special applications.
575:
576: deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
577: memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
578: method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
579: incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
580: set to null if there is no error message. deflateInit2 does not perform any
581: compression: this will be done by deflate().
582: */
583:
584: ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
585: const Bytef *dictionary,
586: uInt dictLength));
587: /*
588: Initializes the compression dictionary from the given byte sequence
589: without producing any compressed output. When using the zlib format, this
590: function must be called immediately after deflateInit, deflateInit2 or
591: deflateReset, and before any call of deflate. When doing raw deflate, this
592: function must be called either before any call of deflate, or immediately
593: after the completion of a deflate block, i.e. after all input has been
594: consumed and all output has been delivered when using any of the flush
595: options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
596: compressor and decompressor must use exactly the same dictionary (see
597: inflateSetDictionary).
598:
599: The dictionary should consist of strings (byte sequences) that are likely
600: to be encountered later in the data to be compressed, with the most commonly
601: used strings preferably put towards the end of the dictionary. Using a
602: dictionary is most useful when the data to be compressed is short and can be
603: predicted with good accuracy; the data can then be compressed better than
604: with the default empty dictionary.
605:
606: Depending on the size of the compression data structures selected by
607: deflateInit or deflateInit2, a part of the dictionary may in effect be
608: discarded, for example if the dictionary is larger than the window size
609: provided in deflateInit or deflateInit2. Thus the strings most likely to be
610: useful should be put at the end of the dictionary, not at the front. In
611: addition, the current implementation of deflate will use at most the window
612: size minus 262 bytes of the provided dictionary.
613:
614: Upon return of this function, strm->adler is set to the adler32 value
615: of the dictionary; the decompressor may later use this value to determine
616: which dictionary has been used by the compressor. (The adler32 value
617: applies to the whole dictionary even if only a subset of the dictionary is
618: actually used by the compressor.) If a raw deflate was requested, then the
619: adler32 value is not computed and strm->adler is not set.
620:
621: deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
622: parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
623: inconsistent (for example if deflate has already been called for this stream
624: or if not at a block boundary for raw deflate). deflateSetDictionary does
625: not perform any compression: this will be done by deflate().
626: */
627:
628: ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
629: z_streamp source));
630: /*
631: Sets the destination stream as a complete copy of the source stream.
632:
633: This function can be useful when several compression strategies will be
634: tried, for example when there are several ways of pre-processing the input
635: data with a filter. The streams that will be discarded should then be freed
636: by calling deflateEnd. Note that deflateCopy duplicates the internal
637: compression state which can be quite large, so this strategy is slow and can
638: consume lots of memory.
639:
640: deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
641: enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
642: (such as zalloc being Z_NULL). msg is left unchanged in both source and
643: destination.
644: */
645:
646: ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
647: /*
648: This function is equivalent to deflateEnd followed by deflateInit,
649: but does not free and reallocate all the internal compression state. The
650: stream will keep the same compression level and any other attributes that
651: may have been set by deflateInit2.
652:
653: deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
654: stream state was inconsistent (such as zalloc or state being Z_NULL).
655: */
656:
657: ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
658: int level,
659: int strategy));
660: /*
661: Dynamically update the compression level and compression strategy. The
662: interpretation of level and strategy is as in deflateInit2. This can be
663: used to switch between compression and straight copy of the input data, or
664: to switch to a different kind of input data requiring a different strategy.
665: If the compression level is changed, the input available so far is
666: compressed with the old level (and may be flushed); the new level will take
667: effect only at the next call of deflate().
668:
669: Before the call of deflateParams, the stream state must be set as for
670: a call of deflate(), since the currently available input may have to be
671: compressed and flushed. In particular, strm->avail_out must be non-zero.
672:
673: deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
674: stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if
675: strm->avail_out was zero.
676: */
677:
678: ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
679: int good_length,
680: int max_lazy,
681: int nice_length,
682: int max_chain));
683: /*
684: Fine tune deflate's internal compression parameters. This should only be
685: used by someone who understands the algorithm used by zlib's deflate for
686: searching for the best matching string, and even then only by the most
687: fanatic optimizer trying to squeeze out the last compressed bit for their
688: specific input data. Read the deflate.c source code for the meaning of the
689: max_lazy, good_length, nice_length, and max_chain parameters.
690:
691: deflateTune() can be called after deflateInit() or deflateInit2(), and
692: returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
693: */
694:
695: ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
696: uLong sourceLen));
697: /*
698: deflateBound() returns an upper bound on the compressed size after
699: deflation of sourceLen bytes. It must be called after deflateInit() or
700: deflateInit2(), and after deflateSetHeader(), if used. This would be used
701: to allocate an output buffer for deflation in a single pass, and so would be
702: called before deflate(). If that first deflate() call is provided the
703: sourceLen input bytes, an output buffer allocated to the size returned by
704: deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
705: to return Z_STREAM_END. Note that it is possible for the compressed size to
706: be larger than the value returned by deflateBound() if flush options other
707: than Z_FINISH or Z_NO_FLUSH are used.
708: */
709:
710: ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
711: unsigned *pending,
712: int *bits));
713: /*
714: deflatePending() returns the number of bytes and bits of output that have
715: been generated, but not yet provided in the available output. The bytes not
716: provided would be due to the available output space having being consumed.
717: The number of bits of output not provided are between 0 and 7, where they
718: await more bits to join them in order to fill out a full byte. If pending
719: or bits are Z_NULL, then those values are not set.
720:
721: deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
722: stream state was inconsistent.
723: */
724:
725: ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
726: int bits,
727: int value));
728: /*
729: deflatePrime() inserts bits in the deflate output stream. The intent
730: is that this function is used to start off the deflate output with the bits
731: leftover from a previous deflate stream when appending to it. As such, this
732: function can only be used for raw deflate, and must be used before the first
733: deflate() call after a deflateInit2() or deflateReset(). bits must be less
734: than or equal to 16, and that many of the least significant bits of value
735: will be inserted in the output.
736:
737: deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
738: room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
739: source stream state was inconsistent.
740: */
741:
742: ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
743: gz_headerp head));
744: /*
745: deflateSetHeader() provides gzip header information for when a gzip
746: stream is requested by deflateInit2(). deflateSetHeader() may be called
747: after deflateInit2() or deflateReset() and before the first call of
748: deflate(). The text, time, os, extra field, name, and comment information
749: in the provided gz_header structure are written to the gzip header (xflag is
750: ignored -- the extra flags are set according to the compression level). The
751: caller must assure that, if not Z_NULL, name and comment are terminated with
752: a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
753: available there. If hcrc is true, a gzip header crc is included. Note that
754: the current versions of the command-line version of gzip (up through version
755: 1.3.x) do not support header crc's, and will report that it is a "multi-part
756: gzip file" and give up.
757:
758: If deflateSetHeader is not used, the default gzip header has text false,
759: the time set to zero, and os set to 255, with no extra, name, or comment
760: fields. The gzip header is returned to the default state by deflateReset().
761:
762: deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
763: stream state was inconsistent.
764: */
765:
766: /*
767: ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
768: int windowBits));
769:
770: This is another version of inflateInit with an extra parameter. The
771: fields next_in, avail_in, zalloc, zfree and opaque must be initialized
772: before by the caller.
773:
774: The windowBits parameter is the base two logarithm of the maximum window
775: size (the size of the history buffer). It should be in the range 8..15 for
776: this version of the library. The default value is 15 if inflateInit is used
777: instead. windowBits must be greater than or equal to the windowBits value
778: provided to deflateInit2() while compressing, or it must be equal to 15 if
779: deflateInit2() was not used. If a compressed stream with a larger window
780: size is given as input, inflate() will return with the error code
781: Z_DATA_ERROR instead of trying to allocate a larger window.
782:
783: windowBits can also be zero to request that inflate use the window size in
784: the zlib header of the compressed stream.
785:
786: windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
787: determines the window size. inflate() will then process raw deflate data,
788: not looking for a zlib or gzip header, not generating a check value, and not
789: looking for any check values for comparison at the end of the stream. This
790: is for use with other formats that use the deflate compressed data format
791: such as zip. Those formats provide their own check values. If a custom
792: format is developed using the raw deflate format for compressed data, it is
793: recommended that a check value such as an adler32 or a crc32 be applied to
794: the uncompressed data as is done in the zlib, gzip, and zip formats. For
795: most applications, the zlib format should be used as is. Note that comments
796: above on the use in deflateInit2() applies to the magnitude of windowBits.
797:
798: windowBits can also be greater than 15 for optional gzip decoding. Add
799: 32 to windowBits to enable zlib and gzip decoding with automatic header
800: detection, or add 16 to decode only the gzip format (the zlib format will
801: return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
802: crc32 instead of an adler32.
803:
804: inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
805: memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
806: version assumed by the caller, or Z_STREAM_ERROR if the parameters are
807: invalid, such as a null pointer to the structure. msg is set to null if
808: there is no error message. inflateInit2 does not perform any decompression
809: apart from possibly reading the zlib header if present: actual decompression
810: will be done by inflate(). (So next_in and avail_in may be modified, but
811: next_out and avail_out are unused and unchanged.) The current implementation
812: of inflateInit2() does not process any header information -- that is
813: deferred until inflate() is called.
814: */
815:
816: ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
817: const Bytef *dictionary,
818: uInt dictLength));
819: /*
820: Initializes the decompression dictionary from the given uncompressed byte
821: sequence. This function must be called immediately after a call of inflate,
822: if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
823: can be determined from the adler32 value returned by that call of inflate.
824: The compressor and decompressor must use exactly the same dictionary (see
825: deflateSetDictionary). For raw inflate, this function can be called at any
826: time to set the dictionary. If the provided dictionary is smaller than the
827: window and there is already data in the window, then the provided dictionary
828: will amend what's there. The application must insure that the dictionary
829: that was used for compression is provided.
830:
831: inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
832: parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
833: inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
834: expected one (incorrect adler32 value). inflateSetDictionary does not
835: perform any decompression: this will be done by subsequent calls of
836: inflate().
837: */
838:
839: ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
840: /*
841: Skips invalid compressed data until a possible full flush point (see above
842: for the description of deflate with Z_FULL_FLUSH) can be found, or until all
843: available input is skipped. No output is provided.
844:
845: inflateSync searches for a 00 00 FF FF pattern in the compressed data.
846: All full flush points have this pattern, but not all occurences of this
847: pattern are full flush points.
848:
849: inflateSync returns Z_OK if a possible full flush point has been found,
850: Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
851: has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
852: In the success case, the application may save the current current value of
853: total_in which indicates where valid compressed data was found. In the
854: error case, the application may repeatedly call inflateSync, providing more
855: input each time, until success or end of the input data.
856: */
857:
858: ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
859: z_streamp source));
860: /*
861: Sets the destination stream as a complete copy of the source stream.
862:
863: This function can be useful when randomly accessing a large stream. The
864: first pass through the stream can periodically record the inflate state,
865: allowing restarting inflate at those points when randomly accessing the
866: stream.
867:
868: inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
869: enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
870: (such as zalloc being Z_NULL). msg is left unchanged in both source and
871: destination.
872: */
873:
874: ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
875: /*
876: This function is equivalent to inflateEnd followed by inflateInit,
877: but does not free and reallocate all the internal decompression state. The
878: stream will keep attributes that may have been set by inflateInit2.
879:
880: inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
881: stream state was inconsistent (such as zalloc or state being Z_NULL).
882: */
883:
884: ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
885: int windowBits));
886: /*
887: This function is the same as inflateReset, but it also permits changing
888: the wrap and window size requests. The windowBits parameter is interpreted
889: the same as it is for inflateInit2.
890:
891: inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
892: stream state was inconsistent (such as zalloc or state being Z_NULL), or if
893: the windowBits parameter is invalid.
894: */
895:
896: ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
897: int bits,
898: int value));
899: /*
900: This function inserts bits in the inflate input stream. The intent is
901: that this function is used to start inflating at a bit position in the
902: middle of a byte. The provided bits will be used before any bytes are used
903: from next_in. This function should only be used with raw inflate, and
904: should be used before the first inflate() call after inflateInit2() or
905: inflateReset(). bits must be less than or equal to 16, and that many of the
906: least significant bits of value will be inserted in the input.
907:
908: If bits is negative, then the input stream bit buffer is emptied. Then
909: inflatePrime() can be called again to put bits in the buffer. This is used
910: to clear out bits leftover after feeding inflate a block description prior
911: to feeding inflate codes.
912:
913: inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
914: stream state was inconsistent.
915: */
916:
917: ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
918: /*
919: This function returns two values, one in the lower 16 bits of the return
920: value, and the other in the remaining upper bits, obtained by shifting the
921: return value down 16 bits. If the upper value is -1 and the lower value is
922: zero, then inflate() is currently decoding information outside of a block.
923: If the upper value is -1 and the lower value is non-zero, then inflate is in
924: the middle of a stored block, with the lower value equaling the number of
925: bytes from the input remaining to copy. If the upper value is not -1, then
926: it is the number of bits back from the current bit position in the input of
927: the code (literal or length/distance pair) currently being processed. In
928: that case the lower value is the number of bytes already emitted for that
929: code.
930:
931: A code is being processed if inflate is waiting for more input to complete
932: decoding of the code, or if it has completed decoding but is waiting for
933: more output space to write the literal or match data.
934:
935: inflateMark() is used to mark locations in the input data for random
936: access, which may be at bit positions, and to note those cases where the
937: output of a code may span boundaries of random access blocks. The current
938: location in the input stream can be determined from avail_in and data_type
939: as noted in the description for the Z_BLOCK flush parameter for inflate.
940:
941: inflateMark returns the value noted above or -1 << 16 if the provided
942: source stream state was inconsistent.
943: */
944:
945: ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
946: gz_headerp head));
947: /*
948: inflateGetHeader() requests that gzip header information be stored in the
949: provided gz_header structure. inflateGetHeader() may be called after
950: inflateInit2() or inflateReset(), and before the first call of inflate().
951: As inflate() processes the gzip stream, head->done is zero until the header
952: is completed, at which time head->done is set to one. If a zlib stream is
953: being decoded, then head->done is set to -1 to indicate that there will be
954: no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
955: used to force inflate() to return immediately after header processing is
956: complete and before any actual data is decompressed.
957:
958: The text, time, xflags, and os fields are filled in with the gzip header
959: contents. hcrc is set to true if there is a header CRC. (The header CRC
960: was valid if done is set to one.) If extra is not Z_NULL, then extra_max
961: contains the maximum number of bytes to write to extra. Once done is true,
962: extra_len contains the actual extra field length, and extra contains the
963: extra field, or that field truncated if extra_max is less than extra_len.
964: If name is not Z_NULL, then up to name_max characters are written there,
965: terminated with a zero unless the length is greater than name_max. If
966: comment is not Z_NULL, then up to comm_max characters are written there,
967: terminated with a zero unless the length is greater than comm_max. When any
968: of extra, name, or comment are not Z_NULL and the respective field is not
969: present in the header, then that field is set to Z_NULL to signal its
970: absence. This allows the use of deflateSetHeader() with the returned
971: structure to duplicate the header. However if those fields are set to
972: allocated memory, then the application will need to save those pointers
973: elsewhere so that they can be eventually freed.
974:
975: If inflateGetHeader is not used, then the header information is simply
976: discarded. The header is always checked for validity, including the header
977: CRC if present. inflateReset() will reset the process to discard the header
978: information. The application would need to call inflateGetHeader() again to
979: retrieve the header from the next gzip stream.
980:
981: inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
982: stream state was inconsistent.
983: */
984:
985: /*
986: ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
987: unsigned char FAR *window));
988:
989: Initialize the internal stream state for decompression using inflateBack()
990: calls. The fields zalloc, zfree and opaque in strm must be initialized
991: before the call. If zalloc and zfree are Z_NULL, then the default library-
992: derived memory allocation routines are used. windowBits is the base two
993: logarithm of the window size, in the range 8..15. window is a caller
994: supplied buffer of that size. Except for special applications where it is
995: assured that deflate was used with small window sizes, windowBits must be 15
996: and a 32K byte window must be supplied to be able to decompress general
997: deflate streams.
998:
999: See inflateBack() for the usage of these routines.
1000:
1001: inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
1002: the parameters are invalid, Z_MEM_ERROR if the internal state could not be
1003: allocated, or Z_VERSION_ERROR if the version of the library does not match
1004: the version of the header file.
1005: */
1006:
1007: typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *));
1008: typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
1009:
1010: ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
1011: in_func in, void FAR *in_desc,
1012: out_func out, void FAR *out_desc));
1013: /*
1014: inflateBack() does a raw inflate with a single call using a call-back
1015: interface for input and output. This is more efficient than inflate() for
1016: file i/o applications in that it avoids copying between the output and the
1017: sliding window by simply making the window itself the output buffer. This
1018: function trusts the application to not change the output buffer passed by
1019: the output function, at least until inflateBack() returns.
1020:
1021: inflateBackInit() must be called first to allocate the internal state
1022: and to initialize the state with the user-provided window buffer.
1023: inflateBack() may then be used multiple times to inflate a complete, raw
1024: deflate stream with each call. inflateBackEnd() is then called to free the
1025: allocated state.
1026:
1027: A raw deflate stream is one with no zlib or gzip header or trailer.
1028: This routine would normally be used in a utility that reads zip or gzip
1029: files and writes out uncompressed files. The utility would decode the
1030: header and process the trailer on its own, hence this routine expects only
1031: the raw deflate stream to decompress. This is different from the normal
1032: behavior of inflate(), which expects either a zlib or gzip header and
1033: trailer around the deflate stream.
1034:
1035: inflateBack() uses two subroutines supplied by the caller that are then
1036: called by inflateBack() for input and output. inflateBack() calls those
1037: routines until it reads a complete deflate stream and writes out all of the
1038: uncompressed data, or until it encounters an error. The function's
1039: parameters and return types are defined above in the in_func and out_func
1040: typedefs. inflateBack() will call in(in_desc, &buf) which should return the
1041: number of bytes of provided input, and a pointer to that input in buf. If
1042: there is no input available, in() must return zero--buf is ignored in that
1043: case--and inflateBack() will return a buffer error. inflateBack() will call
1044: out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()
1045: should return zero on success, or non-zero on failure. If out() returns
1046: non-zero, inflateBack() will return with an error. Neither in() nor out()
1047: are permitted to change the contents of the window provided to
1048: inflateBackInit(), which is also the buffer that out() uses to write from.
1049: The length written by out() will be at most the window size. Any non-zero
1050: amount of input may be provided by in().
1051:
1052: For convenience, inflateBack() can be provided input on the first call by
1053: setting strm->next_in and strm->avail_in. If that input is exhausted, then
1054: in() will be called. Therefore strm->next_in must be initialized before
1055: calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
1056: immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
1057: must also be initialized, and then if strm->avail_in is not zero, input will
1058: initially be taken from strm->next_in[0 .. strm->avail_in - 1].
1059:
1060: The in_desc and out_desc parameters of inflateBack() is passed as the
1061: first parameter of in() and out() respectively when they are called. These
1062: descriptors can be optionally used to pass any information that the caller-
1063: supplied in() and out() functions need to do their job.
1064:
1065: On return, inflateBack() will set strm->next_in and strm->avail_in to
1066: pass back any unused input that was provided by the last in() call. The
1067: return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1068: if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1069: in the deflate stream (in which case strm->msg is set to indicate the nature
1070: of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1071: In the case of Z_BUF_ERROR, an input or output error can be distinguished
1072: using strm->next_in which will be Z_NULL only if in() returned an error. If
1073: strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1074: non-zero. (in() will always be called before out(), so strm->next_in is
1075: assured to be defined if out() returns non-zero.) Note that inflateBack()
1076: cannot return Z_OK.
1077: */
1078:
1079: ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
1080: /*
1081: All memory allocated by inflateBackInit() is freed.
1082:
1083: inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1084: state was inconsistent.
1085: */
1086:
1087: ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
1088: /* Return flags indicating compile-time options.
1089:
1090: Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1091: 1.0: size of uInt
1092: 3.2: size of uLong
1093: 5.4: size of voidpf (pointer)
1094: 7.6: size of z_off_t
1095:
1096: Compiler, assembler, and debug options:
1097: 8: DEBUG
1098: 9: ASMV or ASMINF -- use ASM code
1099: 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1100: 11: 0 (reserved)
1101:
1102: One-time table building (smaller code, but not thread-safe if true):
1103: 12: BUILDFIXED -- build static block decoding tables when needed
1104: 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1105: 14,15: 0 (reserved)
1106:
1107: Library content (indicates missing functionality):
1108: 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1109: deflate code when not needed)
1110: 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1111: and decode gzip streams (to avoid linking crc code)
1112: 18-19: 0 (reserved)
1113:
1114: Operation variations (changes in library functionality):
1115: 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1116: 21: FASTEST -- deflate algorithm with only one, lowest compression level
1117: 22,23: 0 (reserved)
1118:
1119: The sprintf variant used by gzprintf (zero is best):
1120: 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1121: 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1122: 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1123:
1124: Remainder:
1125: 27-31: 0 (reserved)
1126: */
1127:
1128: #ifndef Z_SOLO
1129:
1130: /* utility functions */
1131:
1132: /*
1133: The following utility functions are implemented on top of the basic
1134: stream-oriented functions. To simplify the interface, some default options
1135: are assumed (compression level and memory usage, standard memory allocation
1136: functions). The source code of these utility functions can be modified if
1137: you need special options.
1138: */
1139:
1140: ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
1141: const Bytef *source, uLong sourceLen));
1142: /*
1143: Compresses the source buffer into the destination buffer. sourceLen is
1144: the byte length of the source buffer. Upon entry, destLen is the total size
1145: of the destination buffer, which must be at least the value returned by
1146: compressBound(sourceLen). Upon exit, destLen is the actual size of the
1147: compressed buffer.
1148:
1149: compress returns Z_OK if success, Z_MEM_ERROR if there was not
1150: enough memory, Z_BUF_ERROR if there was not enough room in the output
1151: buffer.
1152: */
1153:
1154: ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
1155: const Bytef *source, uLong sourceLen,
1156: int level));
1157: /*
1158: Compresses the source buffer into the destination buffer. The level
1159: parameter has the same meaning as in deflateInit. sourceLen is the byte
1160: length of the source buffer. Upon entry, destLen is the total size of the
1161: destination buffer, which must be at least the value returned by
1162: compressBound(sourceLen). Upon exit, destLen is the actual size of the
1163: compressed buffer.
1164:
1165: compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1166: memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1167: Z_STREAM_ERROR if the level parameter is invalid.
1168: */
1169:
1170: ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
1171: /*
1172: compressBound() returns an upper bound on the compressed size after
1173: compress() or compress2() on sourceLen bytes. It would be used before a
1174: compress() or compress2() call to allocate the destination buffer.
1175: */
1176:
1177: ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
1178: const Bytef *source, uLong sourceLen));
1179: /*
1180: Decompresses the source buffer into the destination buffer. sourceLen is
1181: the byte length of the source buffer. Upon entry, destLen is the total size
1182: of the destination buffer, which must be large enough to hold the entire
1183: uncompressed data. (The size of the uncompressed data must have been saved
1184: previously by the compressor and transmitted to the decompressor by some
1185: mechanism outside the scope of this compression library.) Upon exit, destLen
1186: is the actual size of the uncompressed buffer.
1187:
1188: uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1189: enough memory, Z_BUF_ERROR if there was not enough room in the output
1190: buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In
1191: the case where there is not enough room, uncompress() will fill the output
1192: buffer with the uncompressed data up to that point.
1193: */
1194:
1195: /* gzip file access functions */
1196:
1197: /*
1198: This library supports reading and writing files in gzip (.gz) format with
1199: an interface similar to that of stdio, using the functions that start with
1200: "gz". The gzip format is different from the zlib format. gzip is a gzip
1201: wrapper, documented in RFC 1952, wrapped around a deflate stream.
1202: */
1203:
1204: typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */
1205:
1206: /*
1207: ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1208:
1209: Opens a gzip (.gz) file for reading or writing. The mode parameter is as
1210: in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
1211: a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
1212: compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
1213: for fixed code compression as in "wb9F". (See the description of
1214: deflateInit2 for more information about the strategy parameter.) 'T' will
1215: request transparent writing or appending with no compression and not using
1216: the gzip format.
1217:
1218: "a" can be used instead of "w" to request that the gzip stream that will
1219: be written be appended to the file. "+" will result in an error, since
1220: reading and writing to the same gzip file is not supported.
1221:
1222: These functions, as well as gzip, will read and decode a sequence of gzip
1223: streams in a file. The append function of gzopen() can be used to create
1224: such a file. (Also see gzflush() for another way to do this.) When
1225: appending, gzopen does not test whether the file begins with a gzip stream,
1226: nor does it look for the end of the gzip streams to begin appending. gzopen
1227: will simply append a gzip stream to the existing file.
1228:
1229: gzopen can be used to read a file which is not in gzip format; in this
1230: case gzread will directly read from the file without decompression. When
1231: reading, this will be detected automatically by looking for the magic two-
1232: byte gzip header.
1233:
1234: gzopen returns NULL if the file could not be opened, if there was
1235: insufficient memory to allocate the gzFile state, or if an invalid mode was
1236: specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1237: errno can be checked to determine if the reason gzopen failed was that the
1238: file could not be opened.
1239: */
1240:
1241: ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
1242: /*
1243: gzdopen associates a gzFile with the file descriptor fd. File descriptors
1244: are obtained from calls like open, dup, creat, pipe or fileno (if the file
1245: has been previously opened with fopen). The mode parameter is as in gzopen.
1246:
1247: The next call of gzclose on the returned gzFile will also close the file
1248: descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1249: fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1250: mode);. The duplicated descriptor should be saved to avoid a leak, since
1251: gzdopen does not close fd if it fails. If you are using fileno() to get the
1252: file descriptor from a FILE *, then you will have to use dup() to avoid
1253: double-close()ing the file descriptor. Both gzclose() and fclose() will
1254: close the associated file descriptor, so they need to have different file
1255: descriptors.
1256:
1257: gzdopen returns NULL if there was insufficient memory to allocate the
1258: gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1259: provided, or '+' was provided), or if fd is -1. The file descriptor is not
1260: used until the next gz* read, write, seek, or close operation, so gzdopen
1261: will not detect if fd is invalid (unless fd is -1).
1262: */
1263:
1264: ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
1265: /*
1266: Set the internal buffer size used by this library's functions. The
1267: default buffer size is 8192 bytes. This function must be called after
1268: gzopen() or gzdopen(), and before any other calls that read or write the
1269: file. The buffer memory allocation is always deferred to the first read or
1270: write. Two buffers are allocated, either both of the specified size when
1271: writing, or one of the specified size and the other twice that size when
1272: reading. A larger buffer size of, for example, 64K or 128K bytes will
1273: noticeably increase the speed of decompression (reading).
1274:
1275: The new buffer size also affects the maximum length for gzprintf().
1276:
1277: gzbuffer() returns 0 on success, or -1 on failure, such as being called
1278: too late.
1279: */
1280:
1281: ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1282: /*
1283: Dynamically update the compression level or strategy. See the description
1284: of deflateInit2 for the meaning of these parameters.
1285:
1286: gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
1287: opened for writing.
1288: */
1289:
1290: ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1291: /*
1292: Reads the given number of uncompressed bytes from the compressed file. If
1293: the input file is not in gzip format, gzread copies the given number of
1294: bytes into the buffer directly from the file.
1295:
1296: After reaching the end of a gzip stream in the input, gzread will continue
1297: to read, looking for another gzip stream. Any number of gzip streams may be
1298: concatenated in the input file, and will all be decompressed by gzread().
1299: If something other than a gzip stream is encountered after a gzip stream,
1300: that remaining trailing garbage is ignored (and no error is returned).
1301:
1302: gzread can be used to read a gzip file that is being concurrently written.
1303: Upon reaching the end of the input, gzread will return with the available
1304: data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
1305: gzclearerr can be used to clear the end of file indicator in order to permit
1306: gzread to be tried again. Z_OK indicates that a gzip stream was completed
1307: on the last gzread. Z_BUF_ERROR indicates that the input file ended in the
1308: middle of a gzip stream. Note that gzread does not return -1 in the event
1309: of an incomplete gzip stream. This error is deferred until gzclose(), which
1310: will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
1311: stream. Alternatively, gzerror can be used before gzclose to detect this
1312: case.
1313:
1314: gzread returns the number of uncompressed bytes actually read, less than
1315: len for end of file, or -1 for error.
1316: */
1317:
1318: ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
1319: voidpc buf, unsigned len));
1320: /*
1321: Writes the given number of uncompressed bytes into the compressed file.
1322: gzwrite returns the number of uncompressed bytes written or 0 in case of
1323: error.
1324: */
1325:
1326: ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
1327: /*
1328: Converts, formats, and writes the arguments to the compressed file under
1329: control of the format string, as in fprintf. gzprintf returns the number of
1330: uncompressed bytes actually written, or 0 in case of error. The number of
1331: uncompressed bytes written is limited to 8191, or one less than the buffer
1332: size given to gzbuffer(). The caller should assure that this limit is not
1333: exceeded. If it is exceeded, then gzprintf() will return an error (0) with
1334: nothing written. In this case, there may also be a buffer overflow with
1335: unpredictable consequences, which is possible only if zlib was compiled with
1336: the insecure functions sprintf() or vsprintf() because the secure snprintf()
1337: or vsnprintf() functions were not available. This can be determined using
1338: zlibCompileFlags().
1339: */
1340:
1341: ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
1342: /*
1343: Writes the given null-terminated string to the compressed file, excluding
1344: the terminating null character.
1345:
1346: gzputs returns the number of characters written, or -1 in case of error.
1347: */
1348:
1349: ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
1350: /*
1351: Reads bytes from the compressed file until len-1 characters are read, or a
1352: newline character is read and transferred to buf, or an end-of-file
1353: condition is encountered. If any characters are read or if len == 1, the
1354: string is terminated with a null character. If no characters are read due
1355: to an end-of-file or len < 1, then the buffer is left untouched.
1356:
1357: gzgets returns buf which is a null-terminated string, or it returns NULL
1358: for end-of-file or in case of error. If there was an error, the contents at
1359: buf are indeterminate.
1360: */
1361:
1362: ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1363: /*
1364: Writes c, converted to an unsigned char, into the compressed file. gzputc
1365: returns the value that was written, or -1 in case of error.
1366: */
1367:
1368: ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1369: /*
1370: Reads one byte from the compressed file. gzgetc returns this byte or -1
1371: in case of end of file or error. This is implemented as a macro for speed.
1372: As such, it does not do all of the checking the other functions do. I.e.
1373: it does not check to see if file is NULL, nor whether the structure file
1374: points to has been clobbered or not.
1375: */
1376:
1377: ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1378: /*
1379: Push one character back onto the stream to be read as the first character
1380: on the next read. At least one character of push-back is allowed.
1381: gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1382: fail if c is -1, and may fail if a character has been pushed but not read
1383: yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
1384: output buffer size of pushed characters is allowed. (See gzbuffer above.)
1385: The pushed character will be discarded if the stream is repositioned with
1386: gzseek() or gzrewind().
1387: */
1388:
1389: ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1390: /*
1391: Flushes all pending output into the compressed file. The parameter flush
1392: is as in the deflate() function. The return value is the zlib error number
1393: (see function gzerror below). gzflush is only permitted when writing.
1394:
1395: If the flush parameter is Z_FINISH, the remaining data is written and the
1396: gzip stream is completed in the output. If gzwrite() is called again, a new
1397: gzip stream will be started in the output. gzread() is able to read such
1398: concatented gzip streams.
1399:
1400: gzflush should be called only when strictly necessary because it will
1401: degrade compression if called too often.
1402: */
1403:
1404: /*
1405: ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1406: z_off_t offset, int whence));
1407:
1408: Sets the starting position for the next gzread or gzwrite on the given
1409: compressed file. The offset represents a number of bytes in the
1410: uncompressed data stream. The whence parameter is defined as in lseek(2);
1411: the value SEEK_END is not supported.
1412:
1413: If the file is opened for reading, this function is emulated but can be
1414: extremely slow. If the file is opened for writing, only forward seeks are
1415: supported; gzseek then compresses a sequence of zeroes up to the new
1416: starting position.
1417:
1418: gzseek returns the resulting offset location as measured in bytes from
1419: the beginning of the uncompressed stream, or -1 in case of error, in
1420: particular if the file is opened for writing and the new starting position
1421: would be before the current position.
1422: */
1423:
1424: ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
1425: /*
1426: Rewinds the given file. This function is supported only for reading.
1427:
1428: gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1429: */
1430:
1431: /*
1432: ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
1433:
1434: Returns the starting position for the next gzread or gzwrite on the given
1435: compressed file. This position represents a number of bytes in the
1436: uncompressed data stream, and is zero when starting, even if appending or
1437: reading a gzip stream from the middle of a file using gzdopen().
1438:
1439: gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1440: */
1441:
1442: /*
1443: ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
1444:
1445: Returns the current offset in the file being read or written. This offset
1446: includes the count of bytes that precede the gzip stream, for example when
1447: appending or when using gzdopen() for reading. When reading, the offset
1448: does not include as yet unused buffered input. This information can be used
1449: for a progress indicator. On error, gzoffset() returns -1.
1450: */
1451:
1452: ZEXTERN int ZEXPORT gzeof OF((gzFile file));
1453: /*
1454: Returns true (1) if the end-of-file indicator has been set while reading,
1455: false (0) otherwise. Note that the end-of-file indicator is set only if the
1456: read tried to go past the end of the input, but came up short. Therefore,
1457: just like feof(), gzeof() may return false even if there is no more data to
1458: read, in the event that the last read request was for the exact number of
1459: bytes remaining in the input file. This will happen if the input file size
1460: is an exact multiple of the buffer size.
1461:
1462: If gzeof() returns true, then the read functions will return no more data,
1463: unless the end-of-file indicator is reset by gzclearerr() and the input file
1464: has grown since the previous end of file was detected.
1465: */
1466:
1467: ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
1468: /*
1469: Returns true (1) if file is being copied directly while reading, or false
1470: (0) if file is a gzip stream being decompressed.
1471:
1472: If the input file is empty, gzdirect() will return true, since the input
1473: does not contain a gzip stream.
1474:
1475: If gzdirect() is used immediately after gzopen() or gzdopen() it will
1476: cause buffers to be allocated to allow reading the file to determine if it
1477: is a gzip file. Therefore if gzbuffer() is used, it should be called before
1478: gzdirect().
1479:
1480: When writing, gzdirect() returns true (1) if transparent writing was
1481: requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note:
1482: gzdirect() is not needed when writing. Transparent writing must be
1483: explicitly requested, so the application already knows the answer. When
1484: linking statically, using gzdirect() will include all of the zlib code for
1485: gzip file reading and decompression, which may not be desired.)
1486: */
1487:
1488: ZEXTERN int ZEXPORT gzclose OF((gzFile file));
1489: /*
1490: Flushes all pending output if necessary, closes the compressed file and
1491: deallocates the (de)compression state. Note that once file is closed, you
1492: cannot call gzerror with file, since its structures have been deallocated.
1493: gzclose must not be called more than once on the same file, just as free
1494: must not be called more than once on the same allocation.
1495:
1496: gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1497: file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
1498: last read ended in the middle of a gzip stream, or Z_OK on success.
1499: */
1500:
1501: ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
1502: ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
1503: /*
1504: Same as gzclose(), but gzclose_r() is only for use when reading, and
1505: gzclose_w() is only for use when writing or appending. The advantage to
1506: using these instead of gzclose() is that they avoid linking in zlib
1507: compression or decompression code that is not used when only reading or only
1508: writing respectively. If gzclose() is used, then both compression and
1509: decompression code will be included the application when linking to a static
1510: zlib library.
1511: */
1512:
1513: ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
1514: /*
1515: Returns the error message for the last error which occurred on the given
1516: compressed file. errnum is set to zlib error number. If an error occurred
1517: in the file system and not in the compression library, errnum is set to
1518: Z_ERRNO and the application may consult errno to get the exact error code.
1519:
1520: The application must not modify the returned string. Future calls to
1521: this function may invalidate the previously returned string. If file is
1522: closed, then the string previously returned by gzerror will no longer be
1523: available.
1524:
1525: gzerror() should be used to distinguish errors from end-of-file for those
1526: functions above that do not distinguish those cases in their return values.
1527: */
1528:
1529: ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1530: /*
1531: Clears the error and end-of-file flags for file. This is analogous to the
1532: clearerr() function in stdio. This is useful for continuing to read a gzip
1533: file that is being written concurrently.
1534: */
1535:
1536: #endif /* !Z_SOLO */
1537:
1538: /* checksum functions */
1539:
1540: /*
1541: These functions are not related to compression but are exported
1542: anyway because they might be useful in applications using the compression
1543: library.
1544: */
1545:
1546: ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
1547: /*
1548: Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1549: return the updated checksum. If buf is Z_NULL, this function returns the
1550: required initial value for the checksum.
1551:
1552: An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1553: much faster.
1554:
1555: Usage example:
1556:
1557: uLong adler = adler32(0L, Z_NULL, 0);
1558:
1559: while (read_buffer(buffer, length) != EOF) {
1560: adler = adler32(adler, buffer, length);
1561: }
1562: if (adler != original_adler) error();
1563: */
1564:
1565: /*
1566: ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
1567: z_off_t len2));
1568:
1569: Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1570: and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1571: each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1572: seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note
1573: that the z_off_t type (like off_t) is a signed integer. If len2 is
1574: negative, the result has no meaning or utility.
1575: */
1576:
1577: ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
1578: /*
1579: Update a running CRC-32 with the bytes buf[0..len-1] and return the
1580: updated CRC-32. If buf is Z_NULL, this function returns the required
1581: initial value for the for the crc. Pre- and post-conditioning (one's
1582: complement) is performed within this function so it shouldn't be done by the
1583: application.
1584:
1585: Usage example:
1586:
1587: uLong crc = crc32(0L, Z_NULL, 0);
1588:
1589: while (read_buffer(buffer, length) != EOF) {
1590: crc = crc32(crc, buffer, length);
1591: }
1592: if (crc != original_crc) error();
1593: */
1594:
1595: /*
1596: ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1597:
1598: Combine two CRC-32 check values into one. For two sequences of bytes,
1599: seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1600: calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1601: check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1602: len2.
1603: */
1604:
1605:
1606: /* various hacks, don't look :) */
1607:
1608: /* deflateInit and inflateInit are macros to allow checking the zlib version
1609: * and the compiler's view of z_stream:
1610: */
1611: ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1612: const char *version, int stream_size));
1613: ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
1614: const char *version, int stream_size));
1615: ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
1616: int windowBits, int memLevel,
1617: int strategy, const char *version,
1618: int stream_size));
1619: ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
1620: const char *version, int stream_size));
1621: ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
1622: unsigned char FAR *window,
1623: const char *version,
1624: int stream_size));
1625: #define deflateInit(strm, level) \
1626: deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1627: #define inflateInit(strm) \
1628: inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1629: #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1630: deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1631: (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1632: #define inflateInit2(strm, windowBits) \
1633: inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1634: (int)sizeof(z_stream))
1635: #define inflateBackInit(strm, windowBits, window) \
1636: inflateBackInit_((strm), (windowBits), (window), \
1637: ZLIB_VERSION, (int)sizeof(z_stream))
1638:
1639: #ifndef Z_SOLO
1640:
1641: /* gzgetc() macro and its supporting function and exposed data structure. Note
1642: * that the real internal state is much larger than the exposed structure.
1643: * This abbreviated structure exposes just enough for the gzgetc() macro. The
1644: * user should not mess with these exposed elements, since their names or
1645: * behavior could change in the future, perhaps even capriciously. They can
1646: * only be used by the gzgetc() macro. You have been warned.
1647: */
1648: struct gzFile_s {
1649: unsigned have;
1650: unsigned char *next;
1651: z_off64_t pos;
1652: };
1653: ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file));
1654: #define gzgetc(g) \
1655: ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc_(g))
1656:
1657: /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1658: * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1659: * both are true, the application gets the *64 functions, and the regular
1660: * functions are changed to 64 bits) -- in case these are set on systems
1661: * without large file support, _LFS64_LARGEFILE must also be true
1662: */
1663: #if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0
1664: ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1665: ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
1666: ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
1667: ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
1668: ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
1669: ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
1670: #endif
1671:
1672: #if !defined(ZLIB_INTERNAL) && _FILE_OFFSET_BITS-0 == 64 && _LFS64_LARGEFILE-0
1673: # ifdef Z_PREFIX_SET
1674: # define z_gzopen z_gzopen64
1675: # define z_gzseek z_gzseek64
1676: # define z_gztell z_gztell64
1677: # define z_gzoffset z_gzoffset64
1678: # define z_adler32_combine z_adler32_combine64
1679: # define z_crc32_combine z_crc32_combine64
1680: # else
1681: # define gzopen gzopen64
1682: # define gzseek gzseek64
1683: # define gztell gztell64
1684: # define gzoffset gzoffset64
1685: # define adler32_combine adler32_combine64
1686: # define crc32_combine crc32_combine64
1687: # endif
1688: # ifndef _LARGEFILE64_SOURCE
1689: ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1690: ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
1691: ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
1692: ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
1693: ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
1694: ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
1695: # endif
1696: #else
1697: ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
1698: ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
1699: ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
1700: ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
1701: ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1702: ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1703: #endif
1704:
1705: #else /* Z_SOLO */
1706:
1707: ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1708: ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1709:
1710: #endif /* !Z_SOLO */
1711:
1712: /* hack for buggy compilers */
1713: #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
1714: struct internal_state {int dummy;};
1715: #endif
1716:
1717: /* undocumented functions */
1718: ZEXTERN const char * ZEXPORT zError OF((int));
1719: ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));
1720: ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void));
1721: ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int));
1722: ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp));
1723: ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp));
1724: #ifndef Z_SOLO
1725: ZEXTERN unsigned long ZEXPORT gzflags OF((void));
1726: #endif
1727:
1728: #ifdef __cplusplus
1729: }
1730: #endif
1731:
1732: #endif /* ZLIB_H */
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