1: /* zlib.h -- interface of the 'zlib' general purpose compression library
2: version 1.2.8, April 28th, 2013
3:
4: Copyright (C) 1995-2013 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 "1.2.8"
41: #define ZLIB_VERNUM 0x1280
42: #define ZLIB_VER_MAJOR 1
43: #define ZLIB_VER_MINOR 2
44: #define ZLIB_VER_REVISION 8
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: #define Z_INSERT_ONLY 7
173:
174: #define Z_OK 0
175: #define Z_STREAM_END 1
176: #define Z_NEED_DICT 2
177: #define Z_ERRNO (-1)
178: #define Z_STREAM_ERROR (-2)
179: #define Z_DATA_ERROR (-3)
180: #define Z_MEM_ERROR (-4)
181: #define Z_BUF_ERROR (-5)
182: #define Z_VERSION_ERROR (-6)
183: /* Return codes for the compression/decompression functions. Negative values
184: * are errors, positive values are used for special but normal events.
185: */
186:
187: #define Z_NO_COMPRESSION 0
188: #define Z_BEST_SPEED 1
189: #define Z_BEST_COMPRESSION 9
190: #define Z_DEFAULT_COMPRESSION (-1)
191: /* compression levels */
192:
193: #define Z_FILTERED 1
194: #define Z_HUFFMAN_ONLY 2
195: #define Z_RLE 3
196: #define Z_FIXED 4
197: #define Z_DEFAULT_STRATEGY 0
198: /* compression strategy; see deflateInit2() below for details */
199:
200: #define Z_BINARY 0
201: #define Z_TEXT 1
202: #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
203: #define Z_UNKNOWN 2
204: /* Possible values of the data_type field (though see inflate()) */
205:
206: #define Z_DEFLATED 8
207: /* The deflate compression method (the only one supported in this version) */
208:
209: #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
210:
211: #define zlib_version zlibVersion()
212: /* for compatibility with versions < 1.0.2 */
213:
214:
215: /* basic functions */
216:
217: ZEXTERN const char * ZEXPORT zlibVersion OF((void));
218: /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
219: If the first character differs, the library code actually used is not
220: compatible with the zlib.h header file used by the application. This check
221: is automatically made by deflateInit and inflateInit.
222: */
223:
224: /*
225: ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
226:
227: Initializes the internal stream state for compression. The fields
228: zalloc, zfree and opaque must be initialized before by the caller. If
229: zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
230: allocation functions.
231:
232: The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
233: 1 gives best speed, 9 gives best compression, 0 gives no compression at all
234: (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
235: requests a default compromise between speed and compression (currently
236: equivalent to level 6).
237:
238: deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
239: memory, Z_STREAM_ERROR if level is not a valid compression level, or
240: Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
241: with the version assumed by the caller (ZLIB_VERSION). msg is set to null
242: if there is no error message. deflateInit does not perform any compression:
243: this will be done by deflate().
244: */
245:
246:
247: ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
248: /*
249: deflate compresses as much data as possible, and stops when the input
250: buffer becomes empty or the output buffer becomes full. It may introduce
251: some output latency (reading input without producing any output) except when
252: forced to flush.
253:
254: The detailed semantics are as follows. deflate performs one or both of the
255: following actions:
256:
257: - Compress more input starting at next_in and update next_in and avail_in
258: accordingly. If not all input can be processed (because there is not
259: enough room in the output buffer), next_in and avail_in are updated and
260: processing will resume at this point for the next call of deflate().
261:
262: - Provide more output starting at next_out and update next_out and avail_out
263: accordingly. This action is forced if the parameter flush is non zero.
264: Forcing flush frequently degrades the compression ratio, so this parameter
265: should be set only when necessary (in interactive applications). Some
266: output may be provided even if flush is not set.
267:
268: Before the call of deflate(), the application should ensure that at least
269: one of the actions is possible, by providing more input and/or consuming more
270: output, and updating avail_in or avail_out accordingly; avail_out should
271: never be zero before the call. The application can consume the compressed
272: output when it wants, for example when the output buffer is full (avail_out
273: == 0), or after each call of deflate(). If deflate returns Z_OK and with
274: zero avail_out, it must be called again after making room in the output
275: buffer because there might be more output pending.
276:
277: Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
278: decide how much data to accumulate before producing output, in order to
279: maximize compression.
280:
281: If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
282: flushed to the output buffer and the output is aligned on a byte boundary, so
283: that the decompressor can get all input data available so far. (In
284: particular avail_in is zero after the call if enough output space has been
285: provided before the call.) Flushing may degrade compression for some
286: compression algorithms and so it should be used only when necessary. This
287: completes the current deflate block and follows it with an empty stored block
288: that is three bits plus filler bits to the next byte, followed by four bytes
289: (00 00 ff ff).
290:
291: If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
292: output buffer, but the output is not aligned to a byte boundary. All of the
293: input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
294: This completes the current deflate block and follows it with an empty fixed
295: codes block that is 10 bits long. This assures that enough bytes are output
296: in order for the decompressor to finish the block before the empty fixed code
297: block.
298:
299: If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
300: for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
301: seven bits of the current block are held to be written as the next byte after
302: the next deflate block is completed. In this case, the decompressor may not
303: be provided enough bits at this point in order to complete decompression of
304: the data provided so far to the compressor. It may need to wait for the next
305: block to be emitted. This is for advanced applications that need to control
306: the emission of deflate blocks.
307:
308: If flush is set to Z_FULL_FLUSH, all output is flushed as with
309: Z_SYNC_FLUSH, and the compression state is reset so that decompression can
310: restart from this point if previous compressed data has been damaged or if
311: random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
312: compression.
313:
314: If deflate returns with avail_out == 0, this function must be called again
315: with the same value of the flush parameter and more output space (updated
316: avail_out), until the flush is complete (deflate returns with non-zero
317: avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
318: avail_out is greater than six to avoid repeated flush markers due to
319: avail_out == 0 on return.
320:
321: If the parameter flush is set to Z_FINISH, pending input is processed,
322: pending output is flushed and deflate returns with Z_STREAM_END if there was
323: enough output space; if deflate returns with Z_OK, this function must be
324: called again with Z_FINISH and more output space (updated avail_out) but no
325: more input data, until it returns with Z_STREAM_END or an error. After
326: deflate has returned Z_STREAM_END, the only possible operations on the stream
327: are deflateReset or deflateEnd.
328:
329: Z_FINISH can be used immediately after deflateInit if all the compression
330: is to be done in a single step. In this case, avail_out must be at least the
331: value returned by deflateBound (see below). Then deflate is guaranteed to
332: return Z_STREAM_END. If not enough output space is provided, deflate will
333: not return Z_STREAM_END, and it must be called again as described above.
334:
335: deflate() sets strm->adler to the adler32 checksum of all input read
336: so far (that is, total_in bytes).
337:
338: deflate() may update strm->data_type if it can make a good guess about
339: the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
340: binary. This field is only for information purposes and does not affect the
341: compression algorithm in any manner.
342:
343: deflate() returns Z_OK if some progress has been made (more input
344: processed or more output produced), Z_STREAM_END if all input has been
345: consumed and all output has been produced (only when flush is set to
346: Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
347: if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible
348: (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
349: fatal, and deflate() can be called again with more input and more output
350: space to continue compressing.
351: */
352:
353:
354: ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
355: /*
356: All dynamically allocated data structures for this stream are freed.
357: This function discards any unprocessed input and does not flush any pending
358: output.
359:
360: deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
361: stream state was inconsistent, Z_DATA_ERROR if the stream was freed
362: prematurely (some input or output was discarded). In the error case, msg
363: may be set but then points to a static string (which must not be
364: deallocated).
365: */
366:
367:
368: /*
369: ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
370:
371: Initializes the internal stream state for decompression. The fields
372: next_in, avail_in, zalloc, zfree and opaque must be initialized before by
373: the caller. If next_in is not Z_NULL and avail_in is large enough (the
374: exact value depends on the compression method), inflateInit determines the
375: compression method from the zlib header and allocates all data structures
376: accordingly; otherwise the allocation will be deferred to the first call of
377: inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
378: use default allocation functions.
379:
380: inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
381: memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
382: version assumed by the caller, or Z_STREAM_ERROR if the parameters are
383: invalid, such as a null pointer to the structure. msg is set to null if
384: there is no error message. inflateInit does not perform any decompression
385: apart from possibly reading the zlib header if present: actual decompression
386: will be done by inflate(). (So next_in and avail_in may be modified, but
387: next_out and avail_out are unused and unchanged.) The current implementation
388: of inflateInit() does not process any header information -- that is deferred
389: until inflate() is called.
390: */
391:
392:
393: ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
394: /*
395: inflate decompresses as much data as possible, and stops when the input
396: buffer becomes empty or the output buffer becomes full. It may introduce
397: some output latency (reading input without producing any output) except when
398: forced to flush.
399:
400: The detailed semantics are as follows. inflate performs one or both of the
401: following actions:
402:
403: - Decompress more input starting at next_in and update next_in and avail_in
404: accordingly. If not all input can be processed (because there is not
405: enough room in the output buffer), next_in is updated and processing will
406: resume at this point for the next call of inflate().
407:
408: - Provide more output starting at next_out and update next_out and avail_out
409: accordingly. inflate() provides as much output as possible, until there is
410: no more input data or no more space in the output buffer (see below about
411: the flush parameter).
412:
413: Before the call of inflate(), the application should ensure that at least
414: one of the actions is possible, by providing more input and/or consuming more
415: output, and updating the next_* and avail_* values accordingly. The
416: application can consume the uncompressed output when it wants, for example
417: when the output buffer is full (avail_out == 0), or after each call of
418: inflate(). If inflate returns Z_OK and with zero avail_out, it must be
419: called again after making room in the output buffer because there might be
420: more output pending.
421:
422: The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
423: Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
424: output as possible to the output buffer. Z_BLOCK requests that inflate()
425: stop if and when it gets to the next deflate block boundary. When decoding
426: the zlib or gzip format, this will cause inflate() to return immediately
427: after the header and before the first block. When doing a raw inflate,
428: inflate() will go ahead and process the first block, and will return when it
429: gets to the end of that block, or when it runs out of data.
430:
431: The Z_BLOCK option assists in appending to or combining deflate streams.
432: Also to assist in this, on return inflate() will set strm->data_type to the
433: number of unused bits in the last byte taken from strm->next_in, plus 64 if
434: inflate() is currently decoding the last block in the deflate stream, plus
435: 128 if inflate() returned immediately after decoding an end-of-block code or
436: decoding the complete header up to just before the first byte of the deflate
437: stream. The end-of-block will not be indicated until all of the uncompressed
438: data from that block has been written to strm->next_out. The number of
439: unused bits may in general be greater than seven, except when bit 7 of
440: data_type is set, in which case the number of unused bits will be less than
441: eight. data_type is set as noted here every time inflate() returns for all
442: flush options, and so can be used to determine the amount of currently
443: consumed input in bits.
444:
445: The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
446: end of each deflate block header is reached, before any actual data in that
447: block is decoded. This allows the caller to determine the length of the
448: deflate block header for later use in random access within a deflate block.
449: 256 is added to the value of strm->data_type when inflate() returns
450: immediately after reaching the end of the deflate block header.
451:
452: inflate() should normally be called until it returns Z_STREAM_END or an
453: error. However if all decompression is to be performed in a single step (a
454: single call of inflate), the parameter flush should be set to Z_FINISH. In
455: this case all pending input is processed and all pending output is flushed;
456: avail_out must be large enough to hold all of the uncompressed data for the
457: operation to complete. (The size of the uncompressed data may have been
458: saved by the compressor for this purpose.) The use of Z_FINISH is not
459: required to perform an inflation in one step. However it may be used to
460: inform inflate that a faster approach can be used for the single inflate()
461: call. Z_FINISH also informs inflate to not maintain a sliding window if the
462: stream completes, which reduces inflate's memory footprint. If the stream
463: does not complete, either because not all of the stream is provided or not
464: enough output space is provided, then a sliding window will be allocated and
465: inflate() can be called again to continue the operation as if Z_NO_FLUSH had
466: been used.
467:
468: In this implementation, inflate() always flushes as much output as
469: possible to the output buffer, and always uses the faster approach on the
470: first call. So the effects of the flush parameter in this implementation are
471: on the return value of inflate() as noted below, when inflate() returns early
472: when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
473: memory for a sliding window when Z_FINISH is used.
474:
475: If a preset dictionary is needed after this call (see inflateSetDictionary
476: below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
477: chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
478: strm->adler to the Adler-32 checksum of all output produced so far (that is,
479: total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
480: below. At the end of the stream, inflate() checks that its computed adler32
481: checksum is equal to that saved by the compressor and returns Z_STREAM_END
482: only if the checksum is correct.
483:
484: inflate() can decompress and check either zlib-wrapped or gzip-wrapped
485: deflate data. The header type is detected automatically, if requested when
486: initializing with inflateInit2(). Any information contained in the gzip
487: header is not retained, so applications that need that information should
488: instead use raw inflate, see inflateInit2() below, or inflateBack() and
489: perform their own processing of the gzip header and trailer. When processing
490: gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
491: producted so far. The CRC-32 is checked against the gzip trailer.
492:
493: inflate() returns Z_OK if some progress has been made (more input processed
494: or more output produced), Z_STREAM_END if the end of the compressed data has
495: been reached and all uncompressed output has been produced, Z_NEED_DICT if a
496: preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
497: corrupted (input stream not conforming to the zlib format or incorrect check
498: value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
499: next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,
500: Z_BUF_ERROR if no progress is possible or if there was not enough room in the
501: output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
502: inflate() can be called again with more input and more output space to
503: continue decompressing. If Z_DATA_ERROR is returned, the application may
504: then call inflateSync() to look for a good compression block if a partial
505: recovery of the data is desired.
506: */
507:
508:
509: ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
510: /*
511: All dynamically allocated data structures for this stream are freed.
512: This function discards any unprocessed input and does not flush any pending
513: output.
514:
515: inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
516: was inconsistent. In the error case, msg may be set but then points to a
517: static string (which must not be deallocated).
518: */
519:
520:
521: /* Advanced functions */
522:
523: /*
524: The following functions are needed only in some special applications.
525: */
526:
527: /*
528: ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
529: int level,
530: int method,
531: int windowBits,
532: int memLevel,
533: int strategy));
534:
535: This is another version of deflateInit with more compression options. The
536: fields next_in, zalloc, zfree and opaque must be initialized before by the
537: caller.
538:
539: The method parameter is the compression method. It must be Z_DEFLATED in
540: this version of the library.
541:
542: The windowBits parameter is the base two logarithm of the window size
543: (the size of the history buffer). It should be in the range 8..15 for this
544: version of the library. Larger values of this parameter result in better
545: compression at the expense of memory usage. The default value is 15 if
546: deflateInit is used instead.
547:
548: windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
549: determines the window size. deflate() will then generate raw deflate data
550: with no zlib header or trailer, and will not compute an adler32 check value.
551:
552: windowBits can also be greater than 15 for optional gzip encoding. Add
553: 16 to windowBits to write a simple gzip header and trailer around the
554: compressed data instead of a zlib wrapper. The gzip header will have no
555: file name, no extra data, no comment, no modification time (set to zero), no
556: header crc, and the operating system will be set to 255 (unknown). If a
557: gzip stream is being written, strm->adler is a crc32 instead of an adler32.
558:
559: The memLevel parameter specifies how much memory should be allocated
560: for the internal compression state. memLevel=1 uses minimum memory but is
561: slow and reduces compression ratio; memLevel=9 uses maximum memory for
562: optimal speed. The default value is 8. See zconf.h for total memory usage
563: as a function of windowBits and memLevel.
564:
565: The strategy parameter is used to tune the compression algorithm. Use the
566: value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
567: filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
568: string match), or Z_RLE to limit match distances to one (run-length
569: encoding). Filtered data consists mostly of small values with a somewhat
570: random distribution. In this case, the compression algorithm is tuned to
571: compress them better. The effect of Z_FILTERED is to force more Huffman
572: coding and less string matching; it is somewhat intermediate between
573: Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
574: fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
575: strategy parameter only affects the compression ratio but not the
576: correctness of the compressed output even if it is not set appropriately.
577: Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
578: decoder for special applications.
579:
580: deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
581: memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
582: method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
583: incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
584: set to null if there is no error message. deflateInit2 does not perform any
585: compression: this will be done by deflate().
586: */
587:
588: ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
589: const Bytef *dictionary,
590: uInt dictLength));
591: /*
592: Initializes the compression dictionary from the given byte sequence
593: without producing any compressed output. When using the zlib format, this
594: function must be called immediately after deflateInit, deflateInit2 or
595: deflateReset, and before any call of deflate. When doing raw deflate, this
596: function must be called either before any call of deflate, or immediately
597: after the completion of a deflate block, i.e. after all input has been
598: consumed and all output has been delivered when using any of the flush
599: options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
600: compressor and decompressor must use exactly the same dictionary (see
601: inflateSetDictionary).
602:
603: The dictionary should consist of strings (byte sequences) that are likely
604: to be encountered later in the data to be compressed, with the most commonly
605: used strings preferably put towards the end of the dictionary. Using a
606: dictionary is most useful when the data to be compressed is short and can be
607: predicted with good accuracy; the data can then be compressed better than
608: with the default empty dictionary.
609:
610: Depending on the size of the compression data structures selected by
611: deflateInit or deflateInit2, a part of the dictionary may in effect be
612: discarded, for example if the dictionary is larger than the window size
613: provided in deflateInit or deflateInit2. Thus the strings most likely to be
614: useful should be put at the end of the dictionary, not at the front. In
615: addition, the current implementation of deflate will use at most the window
616: size minus 262 bytes of the provided dictionary.
617:
618: Upon return of this function, strm->adler is set to the adler32 value
619: of the dictionary; the decompressor may later use this value to determine
620: which dictionary has been used by the compressor. (The adler32 value
621: applies to the whole dictionary even if only a subset of the dictionary is
622: actually used by the compressor.) If a raw deflate was requested, then the
623: adler32 value is not computed and strm->adler is not set.
624:
625: deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
626: parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
627: inconsistent (for example if deflate has already been called for this stream
628: or if not at a block boundary for raw deflate). deflateSetDictionary does
629: not perform any compression: this will be done by deflate().
630: */
631:
632: ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
633: z_streamp source));
634: /*
635: Sets the destination stream as a complete copy of the source stream.
636:
637: This function can be useful when several compression strategies will be
638: tried, for example when there are several ways of pre-processing the input
639: data with a filter. The streams that will be discarded should then be freed
640: by calling deflateEnd. Note that deflateCopy duplicates the internal
641: compression state which can be quite large, so this strategy is slow and can
642: consume lots of memory.
643:
644: deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
645: enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
646: (such as zalloc being Z_NULL). msg is left unchanged in both source and
647: destination.
648: */
649:
650: ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
651: /*
652: This function is equivalent to deflateEnd followed by deflateInit,
653: but does not free and reallocate all the internal compression state. The
654: stream will keep the same compression level and any other attributes that
655: may have been set by deflateInit2.
656:
657: deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
658: stream state was inconsistent (such as zalloc or state being Z_NULL).
659: */
660:
661: ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
662: int level,
663: int strategy));
664: /*
665: Dynamically update the compression level and compression strategy. The
666: interpretation of level and strategy is as in deflateInit2. This can be
667: used to switch between compression and straight copy of the input data, or
668: to switch to a different kind of input data requiring a different strategy.
669: If the compression level is changed, the input available so far is
670: compressed with the old level (and may be flushed); the new level will take
671: effect only at the next call of deflate().
672:
673: Before the call of deflateParams, the stream state must be set as for
674: a call of deflate(), since the currently available input may have to be
675: compressed and flushed. In particular, strm->avail_out must be non-zero.
676:
677: deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
678: stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if
679: strm->avail_out was zero.
680: */
681:
682: ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
683: int good_length,
684: int max_lazy,
685: int nice_length,
686: int max_chain));
687: /*
688: Fine tune deflate's internal compression parameters. This should only be
689: used by someone who understands the algorithm used by zlib's deflate for
690: searching for the best matching string, and even then only by the most
691: fanatic optimizer trying to squeeze out the last compressed bit for their
692: specific input data. Read the deflate.c source code for the meaning of the
693: max_lazy, good_length, nice_length, and max_chain parameters.
694:
695: deflateTune() can be called after deflateInit() or deflateInit2(), and
696: returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
697: */
698:
699: ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
700: uLong sourceLen));
701: /*
702: deflateBound() returns an upper bound on the compressed size after
703: deflation of sourceLen bytes. It must be called after deflateInit() or
704: deflateInit2(), and after deflateSetHeader(), if used. This would be used
705: to allocate an output buffer for deflation in a single pass, and so would be
706: called before deflate(). If that first deflate() call is provided the
707: sourceLen input bytes, an output buffer allocated to the size returned by
708: deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
709: to return Z_STREAM_END. Note that it is possible for the compressed size to
710: be larger than the value returned by deflateBound() if flush options other
711: than Z_FINISH or Z_NO_FLUSH are used.
712: */
713:
714: ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
715: unsigned *pending,
716: int *bits));
717: /*
718: deflatePending() returns the number of bytes and bits of output that have
719: been generated, but not yet provided in the available output. The bytes not
720: provided would be due to the available output space having being consumed.
721: The number of bits of output not provided are between 0 and 7, where they
722: await more bits to join them in order to fill out a full byte. If pending
723: or bits are Z_NULL, then those values are not set.
724:
725: deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
726: stream state was inconsistent.
727: */
728:
729: ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
730: int bits,
731: int value));
732: /*
733: deflatePrime() inserts bits in the deflate output stream. The intent
734: is that this function is used to start off the deflate output with the bits
735: leftover from a previous deflate stream when appending to it. As such, this
736: function can only be used for raw deflate, and must be used before the first
737: deflate() call after a deflateInit2() or deflateReset(). bits must be less
738: than or equal to 16, and that many of the least significant bits of value
739: will be inserted in the output.
740:
741: deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
742: room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
743: source stream state was inconsistent.
744: */
745:
746: ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
747: gz_headerp head));
748: /*
749: deflateSetHeader() provides gzip header information for when a gzip
750: stream is requested by deflateInit2(). deflateSetHeader() may be called
751: after deflateInit2() or deflateReset() and before the first call of
752: deflate(). The text, time, os, extra field, name, and comment information
753: in the provided gz_header structure are written to the gzip header (xflag is
754: ignored -- the extra flags are set according to the compression level). The
755: caller must assure that, if not Z_NULL, name and comment are terminated with
756: a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
757: available there. If hcrc is true, a gzip header crc is included. Note that
758: the current versions of the command-line version of gzip (up through version
759: 1.3.x) do not support header crc's, and will report that it is a "multi-part
760: gzip file" and give up.
761:
762: If deflateSetHeader is not used, the default gzip header has text false,
763: the time set to zero, and os set to 255, with no extra, name, or comment
764: fields. The gzip header is returned to the default state by deflateReset().
765:
766: deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
767: stream state was inconsistent.
768: */
769:
770: /*
771: ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
772: int windowBits));
773:
774: This is another version of inflateInit with an extra parameter. The
775: fields next_in, avail_in, zalloc, zfree and opaque must be initialized
776: before by the caller.
777:
778: The windowBits parameter is the base two logarithm of the maximum window
779: size (the size of the history buffer). It should be in the range 8..15 for
780: this version of the library. The default value is 15 if inflateInit is used
781: instead. windowBits must be greater than or equal to the windowBits value
782: provided to deflateInit2() while compressing, or it must be equal to 15 if
783: deflateInit2() was not used. If a compressed stream with a larger window
784: size is given as input, inflate() will return with the error code
785: Z_DATA_ERROR instead of trying to allocate a larger window.
786:
787: windowBits can also be zero to request that inflate use the window size in
788: the zlib header of the compressed stream.
789:
790: windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
791: determines the window size. inflate() will then process raw deflate data,
792: not looking for a zlib or gzip header, not generating a check value, and not
793: looking for any check values for comparison at the end of the stream. This
794: is for use with other formats that use the deflate compressed data format
795: such as zip. Those formats provide their own check values. If a custom
796: format is developed using the raw deflate format for compressed data, it is
797: recommended that a check value such as an adler32 or a crc32 be applied to
798: the uncompressed data as is done in the zlib, gzip, and zip formats. For
799: most applications, the zlib format should be used as is. Note that comments
800: above on the use in deflateInit2() applies to the magnitude of windowBits.
801:
802: windowBits can also be greater than 15 for optional gzip decoding. Add
803: 32 to windowBits to enable zlib and gzip decoding with automatic header
804: detection, or add 16 to decode only the gzip format (the zlib format will
805: return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
806: crc32 instead of an adler32.
807:
808: inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
809: memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
810: version assumed by the caller, or Z_STREAM_ERROR if the parameters are
811: invalid, such as a null pointer to the structure. msg is set to null if
812: there is no error message. inflateInit2 does not perform any decompression
813: apart from possibly reading the zlib header if present: actual decompression
814: will be done by inflate(). (So next_in and avail_in may be modified, but
815: next_out and avail_out are unused and unchanged.) The current implementation
816: of inflateInit2() does not process any header information -- that is
817: deferred until inflate() is called.
818: */
819:
820: ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
821: const Bytef *dictionary,
822: uInt dictLength));
823: /*
824: Initializes the decompression dictionary from the given uncompressed byte
825: sequence. This function must be called immediately after a call of inflate,
826: if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
827: can be determined from the adler32 value returned by that call of inflate.
828: The compressor and decompressor must use exactly the same dictionary (see
829: deflateSetDictionary). For raw inflate, this function can be called at any
830: time to set the dictionary. If the provided dictionary is smaller than the
831: window and there is already data in the window, then the provided dictionary
832: will amend what's there. The application must insure that the dictionary
833: that was used for compression is provided.
834:
835: inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
836: parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
837: inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
838: expected one (incorrect adler32 value). inflateSetDictionary does not
839: perform any decompression: this will be done by subsequent calls of
840: inflate().
841: */
842:
843: ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm,
844: Bytef *dictionary,
845: uInt *dictLength));
846: /*
847: Returns the sliding dictionary being maintained by inflate. dictLength is
848: set to the number of bytes in the dictionary, and that many bytes are copied
849: to dictionary. dictionary must have enough space, where 32768 bytes is
850: always enough. If inflateGetDictionary() is called with dictionary equal to
851: Z_NULL, then only the dictionary length is returned, and nothing is copied.
852: Similary, if dictLength is Z_NULL, then it is not set.
853:
854: inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
855: stream state is inconsistent.
856: */
857:
858: ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
859: /*
860: Skips invalid compressed data until a possible full flush point (see above
861: for the description of deflate with Z_FULL_FLUSH) can be found, or until all
862: available input is skipped. No output is provided.
863:
864: inflateSync searches for a 00 00 FF FF pattern in the compressed data.
865: All full flush points have this pattern, but not all occurrences of this
866: pattern are full flush points.
867:
868: inflateSync returns Z_OK if a possible full flush point has been found,
869: Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
870: has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
871: In the success case, the application may save the current current value of
872: total_in which indicates where valid compressed data was found. In the
873: error case, the application may repeatedly call inflateSync, providing more
874: input each time, until success or end of the input data.
875: */
876:
877: ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
878: z_streamp source));
879: /*
880: Sets the destination stream as a complete copy of the source stream.
881:
882: This function can be useful when randomly accessing a large stream. The
883: first pass through the stream can periodically record the inflate state,
884: allowing restarting inflate at those points when randomly accessing the
885: stream.
886:
887: inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
888: enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
889: (such as zalloc being Z_NULL). msg is left unchanged in both source and
890: destination.
891: */
892:
893: ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
894: /*
895: This function is equivalent to inflateEnd followed by inflateInit,
896: but does not free and reallocate all the internal decompression state. The
897: stream will keep attributes that may have been set by inflateInit2.
898:
899: inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
900: stream state was inconsistent (such as zalloc or state being Z_NULL).
901: */
902:
903: ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
904: int windowBits));
905: /*
906: This function is the same as inflateReset, but it also permits changing
907: the wrap and window size requests. The windowBits parameter is interpreted
908: the same as it is for inflateInit2.
909:
910: inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
911: stream state was inconsistent (such as zalloc or state being Z_NULL), or if
912: the windowBits parameter is invalid.
913: */
914:
915: ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
916: int bits,
917: int value));
918: /*
919: This function inserts bits in the inflate input stream. The intent is
920: that this function is used to start inflating at a bit position in the
921: middle of a byte. The provided bits will be used before any bytes are used
922: from next_in. This function should only be used with raw inflate, and
923: should be used before the first inflate() call after inflateInit2() or
924: inflateReset(). bits must be less than or equal to 16, and that many of the
925: least significant bits of value will be inserted in the input.
926:
927: If bits is negative, then the input stream bit buffer is emptied. Then
928: inflatePrime() can be called again to put bits in the buffer. This is used
929: to clear out bits leftover after feeding inflate a block description prior
930: to feeding inflate codes.
931:
932: inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
933: stream state was inconsistent.
934: */
935:
936: ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
937: /*
938: This function returns two values, one in the lower 16 bits of the return
939: value, and the other in the remaining upper bits, obtained by shifting the
940: return value down 16 bits. If the upper value is -1 and the lower value is
941: zero, then inflate() is currently decoding information outside of a block.
942: If the upper value is -1 and the lower value is non-zero, then inflate is in
943: the middle of a stored block, with the lower value equaling the number of
944: bytes from the input remaining to copy. If the upper value is not -1, then
945: it is the number of bits back from the current bit position in the input of
946: the code (literal or length/distance pair) currently being processed. In
947: that case the lower value is the number of bytes already emitted for that
948: code.
949:
950: A code is being processed if inflate is waiting for more input to complete
951: decoding of the code, or if it has completed decoding but is waiting for
952: more output space to write the literal or match data.
953:
954: inflateMark() is used to mark locations in the input data for random
955: access, which may be at bit positions, and to note those cases where the
956: output of a code may span boundaries of random access blocks. The current
957: location in the input stream can be determined from avail_in and data_type
958: as noted in the description for the Z_BLOCK flush parameter for inflate.
959:
960: inflateMark returns the value noted above or -1 << 16 if the provided
961: source stream state was inconsistent.
962: */
963:
964: ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
965: gz_headerp head));
966: /*
967: inflateGetHeader() requests that gzip header information be stored in the
968: provided gz_header structure. inflateGetHeader() may be called after
969: inflateInit2() or inflateReset(), and before the first call of inflate().
970: As inflate() processes the gzip stream, head->done is zero until the header
971: is completed, at which time head->done is set to one. If a zlib stream is
972: being decoded, then head->done is set to -1 to indicate that there will be
973: no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
974: used to force inflate() to return immediately after header processing is
975: complete and before any actual data is decompressed.
976:
977: The text, time, xflags, and os fields are filled in with the gzip header
978: contents. hcrc is set to true if there is a header CRC. (The header CRC
979: was valid if done is set to one.) If extra is not Z_NULL, then extra_max
980: contains the maximum number of bytes to write to extra. Once done is true,
981: extra_len contains the actual extra field length, and extra contains the
982: extra field, or that field truncated if extra_max is less than extra_len.
983: If name is not Z_NULL, then up to name_max characters are written there,
984: terminated with a zero unless the length is greater than name_max. If
985: comment is not Z_NULL, then up to comm_max characters are written there,
986: terminated with a zero unless the length is greater than comm_max. When any
987: of extra, name, or comment are not Z_NULL and the respective field is not
988: present in the header, then that field is set to Z_NULL to signal its
989: absence. This allows the use of deflateSetHeader() with the returned
990: structure to duplicate the header. However if those fields are set to
991: allocated memory, then the application will need to save those pointers
992: elsewhere so that they can be eventually freed.
993:
994: If inflateGetHeader is not used, then the header information is simply
995: discarded. The header is always checked for validity, including the header
996: CRC if present. inflateReset() will reset the process to discard the header
997: information. The application would need to call inflateGetHeader() again to
998: retrieve the header from the next gzip stream.
999:
1000: inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
1001: stream state was inconsistent.
1002: */
1003:
1004: /*
1005: ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
1006: unsigned char FAR *window));
1007:
1008: Initialize the internal stream state for decompression using inflateBack()
1009: calls. The fields zalloc, zfree and opaque in strm must be initialized
1010: before the call. If zalloc and zfree are Z_NULL, then the default library-
1011: derived memory allocation routines are used. windowBits is the base two
1012: logarithm of the window size, in the range 8..15. window is a caller
1013: supplied buffer of that size. Except for special applications where it is
1014: assured that deflate was used with small window sizes, windowBits must be 15
1015: and a 32K byte window must be supplied to be able to decompress general
1016: deflate streams.
1017:
1018: See inflateBack() for the usage of these routines.
1019:
1020: inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
1021: the parameters are invalid, Z_MEM_ERROR if the internal state could not be
1022: allocated, or Z_VERSION_ERROR if the version of the library does not match
1023: the version of the header file.
1024: */
1025:
1026: typedef unsigned (*in_func) OF((void FAR *,
1027: z_const unsigned char FAR * FAR *));
1028: typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
1029:
1030: ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
1031: in_func in, void FAR *in_desc,
1032: out_func out, void FAR *out_desc));
1033: /*
1034: inflateBack() does a raw inflate with a single call using a call-back
1035: interface for input and output. This is potentially more efficient than
1036: inflate() for file i/o applications, in that it avoids copying between the
1037: output and the sliding window by simply making the window itself the output
1038: buffer. inflate() can be faster on modern CPUs when used with large
1039: buffers. inflateBack() trusts the application to not change the output
1040: buffer passed by the output function, at least until inflateBack() returns.
1041:
1042: inflateBackInit() must be called first to allocate the internal state
1043: and to initialize the state with the user-provided window buffer.
1044: inflateBack() may then be used multiple times to inflate a complete, raw
1045: deflate stream with each call. inflateBackEnd() is then called to free the
1046: allocated state.
1047:
1048: A raw deflate stream is one with no zlib or gzip header or trailer.
1049: This routine would normally be used in a utility that reads zip or gzip
1050: files and writes out uncompressed files. The utility would decode the
1051: header and process the trailer on its own, hence this routine expects only
1052: the raw deflate stream to decompress. This is different from the normal
1053: behavior of inflate(), which expects either a zlib or gzip header and
1054: trailer around the deflate stream.
1055:
1056: inflateBack() uses two subroutines supplied by the caller that are then
1057: called by inflateBack() for input and output. inflateBack() calls those
1058: routines until it reads a complete deflate stream and writes out all of the
1059: uncompressed data, or until it encounters an error. The function's
1060: parameters and return types are defined above in the in_func and out_func
1061: typedefs. inflateBack() will call in(in_desc, &buf) which should return the
1062: number of bytes of provided input, and a pointer to that input in buf. If
1063: there is no input available, in() must return zero--buf is ignored in that
1064: case--and inflateBack() will return a buffer error. inflateBack() will call
1065: out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()
1066: should return zero on success, or non-zero on failure. If out() returns
1067: non-zero, inflateBack() will return with an error. Neither in() nor out()
1068: are permitted to change the contents of the window provided to
1069: inflateBackInit(), which is also the buffer that out() uses to write from.
1070: The length written by out() will be at most the window size. Any non-zero
1071: amount of input may be provided by in().
1072:
1073: For convenience, inflateBack() can be provided input on the first call by
1074: setting strm->next_in and strm->avail_in. If that input is exhausted, then
1075: in() will be called. Therefore strm->next_in must be initialized before
1076: calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
1077: immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
1078: must also be initialized, and then if strm->avail_in is not zero, input will
1079: initially be taken from strm->next_in[0 .. strm->avail_in - 1].
1080:
1081: The in_desc and out_desc parameters of inflateBack() is passed as the
1082: first parameter of in() and out() respectively when they are called. These
1083: descriptors can be optionally used to pass any information that the caller-
1084: supplied in() and out() functions need to do their job.
1085:
1086: On return, inflateBack() will set strm->next_in and strm->avail_in to
1087: pass back any unused input that was provided by the last in() call. The
1088: return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1089: if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1090: in the deflate stream (in which case strm->msg is set to indicate the nature
1091: of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1092: In the case of Z_BUF_ERROR, an input or output error can be distinguished
1093: using strm->next_in which will be Z_NULL only if in() returned an error. If
1094: strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1095: non-zero. (in() will always be called before out(), so strm->next_in is
1096: assured to be defined if out() returns non-zero.) Note that inflateBack()
1097: cannot return Z_OK.
1098: */
1099:
1100: ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
1101: /*
1102: All memory allocated by inflateBackInit() is freed.
1103:
1104: inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1105: state was inconsistent.
1106: */
1107:
1108: ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
1109: /* Return flags indicating compile-time options.
1110:
1111: Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1112: 1.0: size of uInt
1113: 3.2: size of uLong
1114: 5.4: size of voidpf (pointer)
1115: 7.6: size of z_off_t
1116:
1117: Compiler, assembler, and debug options:
1118: 8: DEBUG
1119: 9: ASMV or ASMINF -- use ASM code
1120: 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1121: 11: 0 (reserved)
1122:
1123: One-time table building (smaller code, but not thread-safe if true):
1124: 12: BUILDFIXED -- build static block decoding tables when needed
1125: 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1126: 14,15: 0 (reserved)
1127:
1128: Library content (indicates missing functionality):
1129: 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1130: deflate code when not needed)
1131: 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1132: and decode gzip streams (to avoid linking crc code)
1133: 18-19: 0 (reserved)
1134:
1135: Operation variations (changes in library functionality):
1136: 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1137: 21: FASTEST -- deflate algorithm with only one, lowest compression level
1138: 22,23: 0 (reserved)
1139:
1140: The sprintf variant used by gzprintf (zero is best):
1141: 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1142: 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1143: 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1144:
1145: Remainder:
1146: 27-31: 0 (reserved)
1147: */
1148:
1149: #ifndef Z_SOLO
1150:
1151: /* utility functions */
1152:
1153: /*
1154: The following utility functions are implemented on top of the basic
1155: stream-oriented functions. To simplify the interface, some default options
1156: are assumed (compression level and memory usage, standard memory allocation
1157: functions). The source code of these utility functions can be modified if
1158: you need special options.
1159: */
1160:
1161: ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
1162: const Bytef *source, uLong sourceLen));
1163: /*
1164: Compresses the source buffer into the destination buffer. sourceLen is
1165: the byte length of the source buffer. Upon entry, destLen is the total size
1166: of the destination buffer, which must be at least the value returned by
1167: compressBound(sourceLen). Upon exit, destLen is the actual size of the
1168: compressed buffer.
1169:
1170: compress returns Z_OK if success, Z_MEM_ERROR if there was not
1171: enough memory, Z_BUF_ERROR if there was not enough room in the output
1172: buffer.
1173: */
1174:
1175: ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
1176: const Bytef *source, uLong sourceLen,
1177: int level));
1178: /*
1179: Compresses the source buffer into the destination buffer. The level
1180: parameter has the same meaning as in deflateInit. sourceLen is the byte
1181: length of the source buffer. Upon entry, destLen is the total size of the
1182: destination buffer, which must be at least the value returned by
1183: compressBound(sourceLen). Upon exit, destLen is the actual size of the
1184: compressed buffer.
1185:
1186: compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1187: memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1188: Z_STREAM_ERROR if the level parameter is invalid.
1189: */
1190:
1191: ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
1192: /*
1193: compressBound() returns an upper bound on the compressed size after
1194: compress() or compress2() on sourceLen bytes. It would be used before a
1195: compress() or compress2() call to allocate the destination buffer.
1196: */
1197:
1198: ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
1199: const Bytef *source, uLong sourceLen));
1200: /*
1201: Decompresses the source buffer into the destination buffer. sourceLen is
1202: the byte length of the source buffer. Upon entry, destLen is the total size
1203: of the destination buffer, which must be large enough to hold the entire
1204: uncompressed data. (The size of the uncompressed data must have been saved
1205: previously by the compressor and transmitted to the decompressor by some
1206: mechanism outside the scope of this compression library.) Upon exit, destLen
1207: is the actual size of the uncompressed buffer.
1208:
1209: uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1210: enough memory, Z_BUF_ERROR if there was not enough room in the output
1211: buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In
1212: the case where there is not enough room, uncompress() will fill the output
1213: buffer with the uncompressed data up to that point.
1214: */
1215:
1216: /* gzip file access functions */
1217:
1218: /*
1219: This library supports reading and writing files in gzip (.gz) format with
1220: an interface similar to that of stdio, using the functions that start with
1221: "gz". The gzip format is different from the zlib format. gzip is a gzip
1222: wrapper, documented in RFC 1952, wrapped around a deflate stream.
1223: */
1224:
1225: typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */
1226:
1227: /*
1228: ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1229:
1230: Opens a gzip (.gz) file for reading or writing. The mode parameter is as
1231: in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
1232: a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
1233: compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
1234: for fixed code compression as in "wb9F". (See the description of
1235: deflateInit2 for more information about the strategy parameter.) 'T' will
1236: request transparent writing or appending with no compression and not using
1237: the gzip format.
1238:
1239: "a" can be used instead of "w" to request that the gzip stream that will
1240: be written be appended to the file. "+" will result in an error, since
1241: reading and writing to the same gzip file is not supported. The addition of
1242: "x" when writing will create the file exclusively, which fails if the file
1243: already exists. On systems that support it, the addition of "e" when
1244: reading or writing will set the flag to close the file on an execve() call.
1245:
1246: These functions, as well as gzip, will read and decode a sequence of gzip
1247: streams in a file. The append function of gzopen() can be used to create
1248: such a file. (Also see gzflush() for another way to do this.) When
1249: appending, gzopen does not test whether the file begins with a gzip stream,
1250: nor does it look for the end of the gzip streams to begin appending. gzopen
1251: will simply append a gzip stream to the existing file.
1252:
1253: gzopen can be used to read a file which is not in gzip format; in this
1254: case gzread will directly read from the file without decompression. When
1255: reading, this will be detected automatically by looking for the magic two-
1256: byte gzip header.
1257:
1258: gzopen returns NULL if the file could not be opened, if there was
1259: insufficient memory to allocate the gzFile state, or if an invalid mode was
1260: specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1261: errno can be checked to determine if the reason gzopen failed was that the
1262: file could not be opened.
1263: */
1264:
1265: ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
1266: /*
1267: gzdopen associates a gzFile with the file descriptor fd. File descriptors
1268: are obtained from calls like open, dup, creat, pipe or fileno (if the file
1269: has been previously opened with fopen). The mode parameter is as in gzopen.
1270:
1271: The next call of gzclose on the returned gzFile will also close the file
1272: descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1273: fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1274: mode);. The duplicated descriptor should be saved to avoid a leak, since
1275: gzdopen does not close fd if it fails. If you are using fileno() to get the
1276: file descriptor from a FILE *, then you will have to use dup() to avoid
1277: double-close()ing the file descriptor. Both gzclose() and fclose() will
1278: close the associated file descriptor, so they need to have different file
1279: descriptors.
1280:
1281: gzdopen returns NULL if there was insufficient memory to allocate the
1282: gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1283: provided, or '+' was provided), or if fd is -1. The file descriptor is not
1284: used until the next gz* read, write, seek, or close operation, so gzdopen
1285: will not detect if fd is invalid (unless fd is -1).
1286: */
1287:
1288: ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
1289: /*
1290: Set the internal buffer size used by this library's functions. The
1291: default buffer size is 8192 bytes. This function must be called after
1292: gzopen() or gzdopen(), and before any other calls that read or write the
1293: file. The buffer memory allocation is always deferred to the first read or
1294: write. Two buffers are allocated, either both of the specified size when
1295: writing, or one of the specified size and the other twice that size when
1296: reading. A larger buffer size of, for example, 64K or 128K bytes will
1297: noticeably increase the speed of decompression (reading).
1298:
1299: The new buffer size also affects the maximum length for gzprintf().
1300:
1301: gzbuffer() returns 0 on success, or -1 on failure, such as being called
1302: too late.
1303: */
1304:
1305: ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1306: /*
1307: Dynamically update the compression level or strategy. See the description
1308: of deflateInit2 for the meaning of these parameters.
1309:
1310: gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
1311: opened for writing.
1312: */
1313:
1314: ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1315: /*
1316: Reads the given number of uncompressed bytes from the compressed file. If
1317: the input file is not in gzip format, gzread copies the given number of
1318: bytes into the buffer directly from the file.
1319:
1320: After reaching the end of a gzip stream in the input, gzread will continue
1321: to read, looking for another gzip stream. Any number of gzip streams may be
1322: concatenated in the input file, and will all be decompressed by gzread().
1323: If something other than a gzip stream is encountered after a gzip stream,
1324: that remaining trailing garbage is ignored (and no error is returned).
1325:
1326: gzread can be used to read a gzip file that is being concurrently written.
1327: Upon reaching the end of the input, gzread will return with the available
1328: data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
1329: gzclearerr can be used to clear the end of file indicator in order to permit
1330: gzread to be tried again. Z_OK indicates that a gzip stream was completed
1331: on the last gzread. Z_BUF_ERROR indicates that the input file ended in the
1332: middle of a gzip stream. Note that gzread does not return -1 in the event
1333: of an incomplete gzip stream. This error is deferred until gzclose(), which
1334: will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
1335: stream. Alternatively, gzerror can be used before gzclose to detect this
1336: case.
1337:
1338: gzread returns the number of uncompressed bytes actually read, less than
1339: len for end of file, or -1 for error.
1340: */
1341:
1342: ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
1343: voidpc buf, unsigned len));
1344: /*
1345: Writes the given number of uncompressed bytes into the compressed file.
1346: gzwrite returns the number of uncompressed bytes written or 0 in case of
1347: error.
1348: */
1349:
1350: ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
1351: /*
1352: Converts, formats, and writes the arguments to the compressed file under
1353: control of the format string, as in fprintf. gzprintf returns the number of
1354: uncompressed bytes actually written, or 0 in case of error. The number of
1355: uncompressed bytes written is limited to 8191, or one less than the buffer
1356: size given to gzbuffer(). The caller should assure that this limit is not
1357: exceeded. If it is exceeded, then gzprintf() will return an error (0) with
1358: nothing written. In this case, there may also be a buffer overflow with
1359: unpredictable consequences, which is possible only if zlib was compiled with
1360: the insecure functions sprintf() or vsprintf() because the secure snprintf()
1361: or vsnprintf() functions were not available. This can be determined using
1362: zlibCompileFlags().
1363: */
1364:
1365: ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
1366: /*
1367: Writes the given null-terminated string to the compressed file, excluding
1368: the terminating null character.
1369:
1370: gzputs returns the number of characters written, or -1 in case of error.
1371: */
1372:
1373: ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
1374: /*
1375: Reads bytes from the compressed file until len-1 characters are read, or a
1376: newline character is read and transferred to buf, or an end-of-file
1377: condition is encountered. If any characters are read or if len == 1, the
1378: string is terminated with a null character. If no characters are read due
1379: to an end-of-file or len < 1, then the buffer is left untouched.
1380:
1381: gzgets returns buf which is a null-terminated string, or it returns NULL
1382: for end-of-file or in case of error. If there was an error, the contents at
1383: buf are indeterminate.
1384: */
1385:
1386: ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1387: /*
1388: Writes c, converted to an unsigned char, into the compressed file. gzputc
1389: returns the value that was written, or -1 in case of error.
1390: */
1391:
1392: ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1393: /*
1394: Reads one byte from the compressed file. gzgetc returns this byte or -1
1395: in case of end of file or error. This is implemented as a macro for speed.
1396: As such, it does not do all of the checking the other functions do. I.e.
1397: it does not check to see if file is NULL, nor whether the structure file
1398: points to has been clobbered or not.
1399: */
1400:
1401: ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1402: /*
1403: Push one character back onto the stream to be read as the first character
1404: on the next read. At least one character of push-back is allowed.
1405: gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1406: fail if c is -1, and may fail if a character has been pushed but not read
1407: yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
1408: output buffer size of pushed characters is allowed. (See gzbuffer above.)
1409: The pushed character will be discarded if the stream is repositioned with
1410: gzseek() or gzrewind().
1411: */
1412:
1413: ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1414: /*
1415: Flushes all pending output into the compressed file. The parameter flush
1416: is as in the deflate() function. The return value is the zlib error number
1417: (see function gzerror below). gzflush is only permitted when writing.
1418:
1419: If the flush parameter is Z_FINISH, the remaining data is written and the
1420: gzip stream is completed in the output. If gzwrite() is called again, a new
1421: gzip stream will be started in the output. gzread() is able to read such
1422: concatented gzip streams.
1423:
1424: gzflush should be called only when strictly necessary because it will
1425: degrade compression if called too often.
1426: */
1427:
1428: /*
1429: ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1430: z_off_t offset, int whence));
1431:
1432: Sets the starting position for the next gzread or gzwrite on the given
1433: compressed file. The offset represents a number of bytes in the
1434: uncompressed data stream. The whence parameter is defined as in lseek(2);
1435: the value SEEK_END is not supported.
1436:
1437: If the file is opened for reading, this function is emulated but can be
1438: extremely slow. If the file is opened for writing, only forward seeks are
1439: supported; gzseek then compresses a sequence of zeroes up to the new
1440: starting position.
1441:
1442: gzseek returns the resulting offset location as measured in bytes from
1443: the beginning of the uncompressed stream, or -1 in case of error, in
1444: particular if the file is opened for writing and the new starting position
1445: would be before the current position.
1446: */
1447:
1448: ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
1449: /*
1450: Rewinds the given file. This function is supported only for reading.
1451:
1452: gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1453: */
1454:
1455: /*
1456: ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
1457:
1458: Returns the starting position for the next gzread or gzwrite on the given
1459: compressed file. This position represents a number of bytes in the
1460: uncompressed data stream, and is zero when starting, even if appending or
1461: reading a gzip stream from the middle of a file using gzdopen().
1462:
1463: gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1464: */
1465:
1466: /*
1467: ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
1468:
1469: Returns the current offset in the file being read or written. This offset
1470: includes the count of bytes that precede the gzip stream, for example when
1471: appending or when using gzdopen() for reading. When reading, the offset
1472: does not include as yet unused buffered input. This information can be used
1473: for a progress indicator. On error, gzoffset() returns -1.
1474: */
1475:
1476: ZEXTERN int ZEXPORT gzeof OF((gzFile file));
1477: /*
1478: Returns true (1) if the end-of-file indicator has been set while reading,
1479: false (0) otherwise. Note that the end-of-file indicator is set only if the
1480: read tried to go past the end of the input, but came up short. Therefore,
1481: just like feof(), gzeof() may return false even if there is no more data to
1482: read, in the event that the last read request was for the exact number of
1483: bytes remaining in the input file. This will happen if the input file size
1484: is an exact multiple of the buffer size.
1485:
1486: If gzeof() returns true, then the read functions will return no more data,
1487: unless the end-of-file indicator is reset by gzclearerr() and the input file
1488: has grown since the previous end of file was detected.
1489: */
1490:
1491: ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
1492: /*
1493: Returns true (1) if file is being copied directly while reading, or false
1494: (0) if file is a gzip stream being decompressed.
1495:
1496: If the input file is empty, gzdirect() will return true, since the input
1497: does not contain a gzip stream.
1498:
1499: If gzdirect() is used immediately after gzopen() or gzdopen() it will
1500: cause buffers to be allocated to allow reading the file to determine if it
1501: is a gzip file. Therefore if gzbuffer() is used, it should be called before
1502: gzdirect().
1503:
1504: When writing, gzdirect() returns true (1) if transparent writing was
1505: requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note:
1506: gzdirect() is not needed when writing. Transparent writing must be
1507: explicitly requested, so the application already knows the answer. When
1508: linking statically, using gzdirect() will include all of the zlib code for
1509: gzip file reading and decompression, which may not be desired.)
1510: */
1511:
1512: ZEXTERN int ZEXPORT gzclose OF((gzFile file));
1513: /*
1514: Flushes all pending output if necessary, closes the compressed file and
1515: deallocates the (de)compression state. Note that once file is closed, you
1516: cannot call gzerror with file, since its structures have been deallocated.
1517: gzclose must not be called more than once on the same file, just as free
1518: must not be called more than once on the same allocation.
1519:
1520: gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1521: file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
1522: last read ended in the middle of a gzip stream, or Z_OK on success.
1523: */
1524:
1525: ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
1526: ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
1527: /*
1528: Same as gzclose(), but gzclose_r() is only for use when reading, and
1529: gzclose_w() is only for use when writing or appending. The advantage to
1530: using these instead of gzclose() is that they avoid linking in zlib
1531: compression or decompression code that is not used when only reading or only
1532: writing respectively. If gzclose() is used, then both compression and
1533: decompression code will be included the application when linking to a static
1534: zlib library.
1535: */
1536:
1537: ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
1538: /*
1539: Returns the error message for the last error which occurred on the given
1540: compressed file. errnum is set to zlib error number. If an error occurred
1541: in the file system and not in the compression library, errnum is set to
1542: Z_ERRNO and the application may consult errno to get the exact error code.
1543:
1544: The application must not modify the returned string. Future calls to
1545: this function may invalidate the previously returned string. If file is
1546: closed, then the string previously returned by gzerror will no longer be
1547: available.
1548:
1549: gzerror() should be used to distinguish errors from end-of-file for those
1550: functions above that do not distinguish those cases in their return values.
1551: */
1552:
1553: ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1554: /*
1555: Clears the error and end-of-file flags for file. This is analogous to the
1556: clearerr() function in stdio. This is useful for continuing to read a gzip
1557: file that is being written concurrently.
1558: */
1559:
1560: #endif /* !Z_SOLO */
1561:
1562: /* checksum functions */
1563:
1564: /*
1565: These functions are not related to compression but are exported
1566: anyway because they might be useful in applications using the compression
1567: library.
1568: */
1569:
1570: ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
1571: /*
1572: Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1573: return the updated checksum. If buf is Z_NULL, this function returns the
1574: required initial value for the checksum.
1575:
1576: An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1577: much faster.
1578:
1579: Usage example:
1580:
1581: uLong adler = adler32(0L, Z_NULL, 0);
1582:
1583: while (read_buffer(buffer, length) != EOF) {
1584: adler = adler32(adler, buffer, length);
1585: }
1586: if (adler != original_adler) error();
1587: */
1588:
1589: /*
1590: ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
1591: z_off_t len2));
1592:
1593: Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1594: and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1595: each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1596: seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note
1597: that the z_off_t type (like off_t) is a signed integer. If len2 is
1598: negative, the result has no meaning or utility.
1599: */
1600:
1601: ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
1602: /*
1603: Update a running CRC-32 with the bytes buf[0..len-1] and return the
1604: updated CRC-32. If buf is Z_NULL, this function returns the required
1605: initial value for the crc. Pre- and post-conditioning (one's complement) is
1606: performed within this function so it shouldn't be done by the application.
1607:
1608: Usage example:
1609:
1610: uLong crc = crc32(0L, Z_NULL, 0);
1611:
1612: while (read_buffer(buffer, length) != EOF) {
1613: crc = crc32(crc, buffer, length);
1614: }
1615: if (crc != original_crc) error();
1616: */
1617:
1618: /*
1619: ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1620:
1621: Combine two CRC-32 check values into one. For two sequences of bytes,
1622: seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1623: calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1624: check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1625: len2.
1626: */
1627:
1628:
1629: /* various hacks, don't look :) */
1630:
1631: /* deflateInit and inflateInit are macros to allow checking the zlib version
1632: * and the compiler's view of z_stream:
1633: */
1634: ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1635: const char *version, int stream_size));
1636: ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
1637: const char *version, int stream_size));
1638: ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
1639: int windowBits, int memLevel,
1640: int strategy, const char *version,
1641: int stream_size));
1642: ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
1643: const char *version, int stream_size));
1644: ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
1645: unsigned char FAR *window,
1646: const char *version,
1647: int stream_size));
1648: #define deflateInit(strm, level) \
1649: deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1650: #define inflateInit(strm) \
1651: inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1652: #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1653: deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1654: (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1655: #define inflateInit2(strm, windowBits) \
1656: inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1657: (int)sizeof(z_stream))
1658: #define inflateBackInit(strm, windowBits, window) \
1659: inflateBackInit_((strm), (windowBits), (window), \
1660: ZLIB_VERSION, (int)sizeof(z_stream))
1661:
1662: #ifndef Z_SOLO
1663:
1664: /* gzgetc() macro and its supporting function and exposed data structure. Note
1665: * that the real internal state is much larger than the exposed structure.
1666: * This abbreviated structure exposes just enough for the gzgetc() macro. The
1667: * user should not mess with these exposed elements, since their names or
1668: * behavior could change in the future, perhaps even capriciously. They can
1669: * only be used by the gzgetc() macro. You have been warned.
1670: */
1671: struct gzFile_s {
1672: unsigned have;
1673: unsigned char *next;
1674: z_off64_t pos;
1675: };
1676: ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */
1677: #ifdef Z_PREFIX_SET
1678: # undef z_gzgetc
1679: # define z_gzgetc(g) \
1680: ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g))
1681: #else
1682: # define gzgetc(g) \
1683: ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g))
1684: #endif
1685:
1686: /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1687: * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1688: * both are true, the application gets the *64 functions, and the regular
1689: * functions are changed to 64 bits) -- in case these are set on systems
1690: * without large file support, _LFS64_LARGEFILE must also be true
1691: */
1692: #ifdef Z_LARGE64
1693: ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1694: ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
1695: ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
1696: ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
1697: ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
1698: ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
1699: #endif
1700:
1701: #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
1702: # ifdef Z_PREFIX_SET
1703: # define z_gzopen z_gzopen64
1704: # define z_gzseek z_gzseek64
1705: # define z_gztell z_gztell64
1706: # define z_gzoffset z_gzoffset64
1707: # define z_adler32_combine z_adler32_combine64
1708: # define z_crc32_combine z_crc32_combine64
1709: # else
1710: # define gzopen gzopen64
1711: # define gzseek gzseek64
1712: # define gztell gztell64
1713: # define gzoffset gzoffset64
1714: # define adler32_combine adler32_combine64
1715: # define crc32_combine crc32_combine64
1716: # endif
1717: # ifndef Z_LARGE64
1718: ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1719: ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
1720: ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
1721: ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
1722: ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
1723: ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
1724: # endif
1725: #else
1726: ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
1727: ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
1728: ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
1729: ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
1730: ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1731: ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1732: #endif
1733:
1734: #else /* Z_SOLO */
1735:
1736: ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1737: ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1738:
1739: #endif /* !Z_SOLO */
1740:
1741: /* hack for buggy compilers */
1742: #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
1743: struct internal_state {int dummy;};
1744: #endif
1745:
1746: /* undocumented functions */
1747: ZEXTERN const char * ZEXPORT zError OF((int));
1748: ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));
1749: ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void));
1750: ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int));
1751: ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp));
1752: ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp));
1753: #if defined(_WIN32) && !defined(Z_SOLO)
1754: ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path,
1755: const char *mode));
1756: #endif
1757: #if defined(STDC) || defined(Z_HAVE_STDARG_H)
1758: # ifndef Z_SOLO
1759: ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file,
1760: const char *format,
1761: va_list va));
1762: # endif
1763: #endif
1764:
1765: #ifdef __cplusplus
1766: }
1767: #endif
1768:
1769: #endif /* ZLIB_H */
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