1/* zlib.h -- interface of the 'zlib' general purpose compression library 
2 version 1.2.11, January 15th, 2017 
3 
4 Copyright (C) 1995-2017 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 
37extern "C" { 
38#endif 
39 
40#define ZLIB_VERSION "1.2.11" 
41#define ZLIB_VERNUM 0x12b0 
42#define ZLIB_VER_MAJOR 1 
43#define ZLIB_VER_MINOR 2 
44#define ZLIB_VER_REVISION 11 
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 and raw deflate streams in 
69 memory as well. 
70 
71 The zlib format was designed to be compact and fast for use in memory 
72 and on communications channels. The gzip format was designed for single- 
73 file compression on file systems, has a larger header than zlib to maintain 
74 directory information, and uses a different, slower check method than zlib. 
75 
76 The library does not install any signal handler. The decoder checks 
77 the consistency of the compressed data, so the library should never crash 
78 even in the case of corrupted input. 
79*/ 
80 
81typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); 
82typedef void (*free_func) OF((voidpf opaque, voidpf address)); 
83 
84struct internal_state; 
85 
86typedef struct z_stream_s { 
87 z_const Bytef *next_in; /* next input byte */ 
88 uInt avail_in; /* number of bytes available at next_in */ 
89 uLong total_in; /* total number of input bytes read so far */ 
90 
91 Bytef *next_out; /* next output byte will go here */ 
92 uInt avail_out; /* remaining free space at next_out */ 
93 uLong total_out; /* total number of bytes output so far */ 
94 
95 z_const char *msg; /* last error message, NULL if no error */ 
96 struct internal_state FAR *state; /* not visible by applications */ 
97 
98 alloc_func zalloc; /* used to allocate the internal state */ 
99 free_func zfree; /* used to free the internal state */ 
100 voidpf opaque; /* private data object passed to zalloc and zfree */ 
101 
102 int data_type; /* best guess about the data type: binary or text 
103 for deflate, or the decoding state for inflate */ 
104 uLong adler; /* Adler-32 or CRC-32 value of the uncompressed data */ 
105 uLong reserved; /* reserved for future use */ 
106} z_stream; 
107 
108typedef z_stream FAR *z_streamp; 
109 
110/* 
111 gzip header information passed to and from zlib routines. See RFC 1952 
112 for more details on the meanings of these fields. 
113*/ 
114typedef struct gz_header_s { 
115 int text; /* true if compressed data believed to be text */ 
116 uLong time; /* modification time */ 
117 int xflags; /* extra flags (not used when writing a gzip file) */ 
118 int os; /* operating system */ 
119 Bytef *extra; /* pointer to extra field or Z_NULL if none */ 
120 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ 
121 uInt extra_max; /* space at extra (only when reading header) */ 
122 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ 
123 uInt name_max; /* space at name (only when reading header) */ 
124 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ 
125 uInt comm_max; /* space at comment (only when reading header) */ 
126 int hcrc; /* true if there was or will be a header crc */ 
127 int done; /* true when done reading gzip header (not used 
128 when writing a gzip file) */ 
129} gz_header; 
130 
131typedef gz_header FAR *gz_headerp; 
132 
133/* 
134 The application must update next_in and avail_in when avail_in has dropped 
135 to zero. It must update next_out and avail_out when avail_out has dropped 
136 to zero. The application must initialize zalloc, zfree and opaque before 
137 calling the init function. All other fields are set by the compression 
138 library and must not be updated by the application. 
139 
140 The opaque value provided by the application will be passed as the first 
141 parameter for calls of zalloc and zfree. This can be useful for custom 
142 memory management. The compression library attaches no meaning to the 
143 opaque value. 
144 
145 zalloc must return Z_NULL if there is not enough memory for the object. 
146 If zlib is used in a multi-threaded application, zalloc and zfree must be 
147 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are 
148 Z_NULL on entry to the initialization function, they are set to internal 
149 routines that use the standard library functions malloc() and free(). 
150 
151 On 16-bit systems, the functions zalloc and zfree must be able to allocate 
152 exactly 65536 bytes, but will not be required to allocate more than this if 
153 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers 
154 returned by zalloc for objects of exactly 65536 bytes *must* have their 
155 offset normalized to zero. The default allocation function provided by this 
156 library ensures this (see zutil.c). To reduce memory requirements and avoid 
157 any allocation of 64K objects, at the expense of compression ratio, compile 
158 the library with -DMAX_WBITS=14 (see zconf.h). 
159 
160 The fields total_in and total_out can be used for statistics or progress 
161 reports. After compression, total_in holds the total size of the 
162 uncompressed data and may be saved for use by the decompressor (particularly 
163 if the decompressor wants to decompress everything in a single step). 
164*/ 
165 
166 /* constants */ 
167 
168#define Z_NO_FLUSH 0 
169#define Z_PARTIAL_FLUSH 1 
170#define Z_SYNC_FLUSH 2 
171#define Z_FULL_FLUSH 3 
172#define Z_FINISH 4 
173#define Z_BLOCK 5 
174#define Z_TREES 6 
175/* Allowed flush values; see deflate() and inflate() below for details */ 
176 
177#define Z_OK 0 
178#define Z_STREAM_END 1 
179#define Z_NEED_DICT 2 
180#define Z_ERRNO (-1) 
181#define Z_STREAM_ERROR (-2) 
182#define Z_DATA_ERROR (-3) 
183#define Z_MEM_ERROR (-4) 
184#define Z_BUF_ERROR (-5) 
185#define Z_VERSION_ERROR (-6) 
186/* Return codes for the compression/decompression functions. Negative values 
187 * are errors, positive values are used for special but normal events. 
188 */ 
189 
190#define Z_NO_COMPRESSION 0 
191#define Z_BEST_SPEED 1 
192#define Z_BEST_COMPRESSION 9 
193#define Z_DEFAULT_COMPRESSION (-1) 
194/* compression levels */ 
195 
196#define Z_FILTERED 1 
197#define Z_HUFFMAN_ONLY 2 
198#define Z_RLE 3 
199#define Z_FIXED 4 
200#define Z_DEFAULT_STRATEGY 0 
201/* compression strategy; see deflateInit2() below for details */ 
202 
203#define Z_BINARY 0 
204#define Z_TEXT 1 
205#define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 
206#define Z_UNKNOWN 2 
207/* Possible values of the data_type field for deflate() */ 
208 
209#define Z_DEFLATED 8 
210/* The deflate compression method (the only one supported in this version) */ 
211 
212#define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 
213 
214#define zlib_version zlibVersion() 
215/* for compatibility with versions < 1.0.2 */ 
216 
217 
218 /* basic functions */ 
219 
220ZEXTERN const char * ZEXPORT zlibVersion OF((void)); 
221/* The application can compare zlibVersion and ZLIB_VERSION for consistency. 
222 If the first character differs, the library code actually used is not 
223 compatible with the zlib.h header file used by the application. This check 
224 is automatically made by deflateInit and inflateInit. 
225 */ 
226 
227/* 
228ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); 
229 
230 Initializes the internal stream state for compression. The fields 
231 zalloc, zfree and opaque must be initialized before by the caller. If 
232 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default 
233 allocation functions. 
234 
235 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 
236 1 gives best speed, 9 gives best compression, 0 gives no compression at all 
237 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION 
238 requests a default compromise between speed and compression (currently 
239 equivalent to level 6). 
240 
241 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 
242 memory, Z_STREAM_ERROR if level is not a valid compression level, or 
243 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 
244 with the version assumed by the caller (ZLIB_VERSION). msg is set to null 
245 if there is no error message. deflateInit does not perform any compression: 
246 this will be done by deflate(). 
247*/ 
248 
249 
250ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); 
251/* 
252 deflate compresses as much data as possible, and stops when the input 
253 buffer becomes empty or the output buffer becomes full. It may introduce 
254 some output latency (reading input without producing any output) except when 
255 forced to flush. 
256 
257 The detailed semantics are as follows. deflate performs one or both of the 
258 following actions: 
259 
260 - Compress more input starting at next_in and update next_in and avail_in 
261 accordingly. If not all input can be processed (because there is not 
262 enough room in the output buffer), next_in and avail_in are updated and 
263 processing will resume at this point for the next call of deflate(). 
264 
265 - Generate more output starting at next_out and update next_out and avail_out 
266 accordingly. This action is forced if the parameter flush is non zero. 
267 Forcing flush frequently degrades the compression ratio, so this parameter 
268 should be set only when necessary. Some output may be provided even if 
269 flush is zero. 
270 
271 Before the call of deflate(), the application should ensure that at least 
272 one of the actions is possible, by providing more input and/or consuming more 
273 output, and updating avail_in or avail_out accordingly; avail_out should 
274 never be zero before the call. The application can consume the compressed 
275 output when it wants, for example when the output buffer is full (avail_out 
276 == 0), or after each call of deflate(). If deflate returns Z_OK and with 
277 zero avail_out, it must be called again after making room in the output 
278 buffer because there might be more output pending. See deflatePending(), 
279 which can be used if desired to determine whether or not there is more ouput 
280 in that case. 
281 
282 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 
283 decide how much data to accumulate before producing output, in order to 
284 maximize compression. 
285 
286 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 
287 flushed to the output buffer and the output is aligned on a byte boundary, so 
288 that the decompressor can get all input data available so far. (In 
289 particular avail_in is zero after the call if enough output space has been 
290 provided before the call.) Flushing may degrade compression for some 
291 compression algorithms and so it should be used only when necessary. This 
292 completes the current deflate block and follows it with an empty stored block 
293 that is three bits plus filler bits to the next byte, followed by four bytes 
294 (00 00 ff ff). 
295 
296 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the 
297 output buffer, but the output is not aligned to a byte boundary. All of the 
298 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. 
299 This completes the current deflate block and follows it with an empty fixed 
300 codes block that is 10 bits long. This assures that enough bytes are output 
301 in order for the decompressor to finish the block before the empty fixed 
302 codes block. 
303 
304 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as 
305 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to 
306 seven bits of the current block are held to be written as the next byte after 
307 the next deflate block is completed. In this case, the decompressor may not 
308 be provided enough bits at this point in order to complete decompression of 
309 the data provided so far to the compressor. It may need to wait for the next 
310 block to be emitted. This is for advanced applications that need to control 
311 the emission of deflate blocks. 
312 
313 If flush is set to Z_FULL_FLUSH, all output is flushed as with 
314 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 
315 restart from this point if previous compressed data has been damaged or if 
316 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 
317 compression. 
318 
319 If deflate returns with avail_out == 0, this function must be called again 
320 with the same value of the flush parameter and more output space (updated 
321 avail_out), until the flush is complete (deflate returns with non-zero 
322 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 
323 avail_out is greater than six to avoid repeated flush markers due to 
324 avail_out == 0 on return. 
325 
326 If the parameter flush is set to Z_FINISH, pending input is processed, 
327 pending output is flushed and deflate returns with Z_STREAM_END if there was 
328 enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this 
329 function must be called again with Z_FINISH and more output space (updated 
330 avail_out) but no more input data, until it returns with Z_STREAM_END or an 
331 error. After deflate has returned Z_STREAM_END, the only possible operations 
332 on the stream are deflateReset or deflateEnd. 
333 
334 Z_FINISH can be used in the first deflate call after deflateInit if all the 
335 compression is to be done in a single step. In order to complete in one 
336 call, avail_out must be at least the value returned by deflateBound (see 
337 below). Then deflate is guaranteed to return Z_STREAM_END. If not enough 
338 output space is provided, deflate will not return Z_STREAM_END, and it must 
339 be called again as described above. 
340 
341 deflate() sets strm->adler to the Adler-32 checksum of all input read 
342 so far (that is, total_in bytes). If a gzip stream is being generated, then 
343 strm->adler will be the CRC-32 checksum of the input read so far. (See 
344 deflateInit2 below.) 
345 
346 deflate() may update strm->data_type if it can make a good guess about 
347 the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is 
348 considered binary. This field is only for information purposes and does not 
349 affect the compression algorithm in any manner. 
350 
351 deflate() returns Z_OK if some progress has been made (more input 
352 processed or more output produced), Z_STREAM_END if all input has been 
353 consumed and all output has been produced (only when flush is set to 
354 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 
355 if next_in or next_out was Z_NULL or the state was inadvertently written over 
356 by the application), or Z_BUF_ERROR if no progress is possible (for example 
357 avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and 
358 deflate() can be called again with more input and more output space to 
359 continue compressing. 
360*/ 
361 
362 
363ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); 
364/* 
365 All dynamically allocated data structures for this stream are freed. 
366 This function discards any unprocessed input and does not flush any pending 
367 output. 
368 
369 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 
370 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 
371 prematurely (some input or output was discarded). In the error case, msg 
372 may be set but then points to a static string (which must not be 
373 deallocated). 
374*/ 
375 
376 
377/* 
378ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); 
379 
380 Initializes the internal stream state for decompression. The fields 
381 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 
382 the caller. In the current version of inflate, the provided input is not 
383 read or consumed. The allocation of a sliding window will be deferred to 
384 the first call of inflate (if the decompression does not complete on the 
385 first call). If zalloc and zfree are set to Z_NULL, inflateInit updates 
386 them to use default allocation functions. 
387 
388 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 
389 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 
390 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 
391 invalid, such as a null pointer to the structure. msg is set to null if 
392 there is no error message. inflateInit does not perform any decompression. 
393 Actual decompression will be done by inflate(). So next_in, and avail_in, 
394 next_out, and avail_out are unused and unchanged. The current 
395 implementation of inflateInit() does not process any header information -- 
396 that is deferred until inflate() is called. 
397*/ 
398 
399 
400ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); 
401/* 
402 inflate decompresses as much data as possible, and stops when the input 
403 buffer becomes empty or the output buffer becomes full. It may introduce 
404 some output latency (reading input without producing any output) except when 
405 forced to flush. 
406 
407 The detailed semantics are as follows. inflate performs one or both of the 
408 following actions: 
409 
410 - Decompress more input starting at next_in and update next_in and avail_in 
411 accordingly. If not all input can be processed (because there is not 
412 enough room in the output buffer), then next_in and avail_in are updated 
413 accordingly, and processing will resume at this point for the next call of 
414 inflate(). 
415 
416 - Generate more output starting at next_out and update next_out and avail_out 
417 accordingly. inflate() provides as much output as possible, until there is 
418 no more input data or no more space in the output buffer (see below about 
419 the flush parameter). 
420 
421 Before the call of inflate(), the application should ensure that at least 
422 one of the actions is possible, by providing more input and/or consuming more 
423 output, and updating the next_* and avail_* values accordingly. If the 
424 caller of inflate() does not provide both available input and available 
425 output space, it is possible that there will be no progress made. The 
426 application can consume the uncompressed output when it wants, for example 
427 when the output buffer is full (avail_out == 0), or after each call of 
428 inflate(). If inflate returns Z_OK and with zero avail_out, it must be 
429 called again after making room in the output buffer because there might be 
430 more output pending. 
431 
432 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, 
433 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much 
434 output as possible to the output buffer. Z_BLOCK requests that inflate() 
435 stop if and when it gets to the next deflate block boundary. When decoding 
436 the zlib or gzip format, this will cause inflate() to return immediately 
437 after the header and before the first block. When doing a raw inflate, 
438 inflate() will go ahead and process the first block, and will return when it 
439 gets to the end of that block, or when it runs out of data. 
440 
441 The Z_BLOCK option assists in appending to or combining deflate streams. 
442 To assist in this, on return inflate() always sets strm->data_type to the 
443 number of unused bits in the last byte taken from strm->next_in, plus 64 if 
444 inflate() is currently decoding the last block in the deflate stream, plus 
445 128 if inflate() returned immediately after decoding an end-of-block code or 
446 decoding the complete header up to just before the first byte of the deflate 
447 stream. The end-of-block will not be indicated until all of the uncompressed 
448 data from that block has been written to strm->next_out. The number of 
449 unused bits may in general be greater than seven, except when bit 7 of 
450 data_type is set, in which case the number of unused bits will be less than 
451 eight. data_type is set as noted here every time inflate() returns for all 
452 flush options, and so can be used to determine the amount of currently 
453 consumed input in bits. 
454 
455 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the 
456 end of each deflate block header is reached, before any actual data in that 
457 block is decoded. This allows the caller to determine the length of the 
458 deflate block header for later use in random access within a deflate block. 
459 256 is added to the value of strm->data_type when inflate() returns 
460 immediately after reaching the end of the deflate block header. 
461 
462 inflate() should normally be called until it returns Z_STREAM_END or an 
463 error. However if all decompression is to be performed in a single step (a 
464 single call of inflate), the parameter flush should be set to Z_FINISH. In 
465 this case all pending input is processed and all pending output is flushed; 
466 avail_out must be large enough to hold all of the uncompressed data for the 
467 operation to complete. (The size of the uncompressed data may have been 
468 saved by the compressor for this purpose.) The use of Z_FINISH is not 
469 required to perform an inflation in one step. However it may be used to 
470 inform inflate that a faster approach can be used for the single inflate() 
471 call. Z_FINISH also informs inflate to not maintain a sliding window if the 
472 stream completes, which reduces inflate's memory footprint. If the stream 
473 does not complete, either because not all of the stream is provided or not 
474 enough output space is provided, then a sliding window will be allocated and 
475 inflate() can be called again to continue the operation as if Z_NO_FLUSH had 
476 been used. 
477 
478 In this implementation, inflate() always flushes as much output as 
479 possible to the output buffer, and always uses the faster approach on the 
480 first call. So the effects of the flush parameter in this implementation are 
481 on the return value of inflate() as noted below, when inflate() returns early 
482 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of 
483 memory for a sliding window when Z_FINISH is used. 
484 
485 If a preset dictionary is needed after this call (see inflateSetDictionary 
486 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary 
487 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 
488 strm->adler to the Adler-32 checksum of all output produced so far (that is, 
489 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 
490 below. At the end of the stream, inflate() checks that its computed Adler-32 
491 checksum is equal to that saved by the compressor and returns Z_STREAM_END 
492 only if the checksum is correct. 
493 
494 inflate() can decompress and check either zlib-wrapped or gzip-wrapped 
495 deflate data. The header type is detected automatically, if requested when 
496 initializing with inflateInit2(). Any information contained in the gzip 
497 header is not retained unless inflateGetHeader() is used. When processing 
498 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output 
499 produced so far. The CRC-32 is checked against the gzip trailer, as is the 
500 uncompressed length, modulo 2^32. 
501 
502 inflate() returns Z_OK if some progress has been made (more input processed 
503 or more output produced), Z_STREAM_END if the end of the compressed data has 
504 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 
505 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 
506 corrupted (input stream not conforming to the zlib format or incorrect check 
507 value, in which case strm->msg points to a string with a more specific 
508 error), Z_STREAM_ERROR if the stream structure was inconsistent (for example 
509 next_in or next_out was Z_NULL, or the state was inadvertently written over 
510 by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR 
511 if no progress was possible or if there was not enough room in the output 
512 buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 
513 inflate() can be called again with more input and more output space to 
514 continue decompressing. If Z_DATA_ERROR is returned, the application may 
515 then call inflateSync() to look for a good compression block if a partial 
516 recovery of the data is to be attempted. 
517*/ 
518 
519 
520ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); 
521/* 
522 All dynamically allocated data structures for this stream are freed. 
523 This function discards any unprocessed input and does not flush any pending 
524 output. 
525 
526 inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state 
527 was inconsistent. 
528*/ 
529 
530 
531 /* Advanced functions */ 
532 
533/* 
534 The following functions are needed only in some special applications. 
535*/ 
536 
537/* 
538ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, 
539 int level, 
540 int method, 
541 int windowBits, 
542 int memLevel, 
543 int strategy)); 
544 
545 This is another version of deflateInit with more compression options. The 
546 fields next_in, zalloc, zfree and opaque must be initialized before by the 
547 caller. 
548 
549 The method parameter is the compression method. It must be Z_DEFLATED in 
550 this version of the library. 
551 
552 The windowBits parameter is the base two logarithm of the window size 
553 (the size of the history buffer). It should be in the range 8..15 for this 
554 version of the library. Larger values of this parameter result in better 
555 compression at the expense of memory usage. The default value is 15 if 
556 deflateInit is used instead. 
557 
558 For the current implementation of deflate(), a windowBits value of 8 (a 
559 window size of 256 bytes) is not supported. As a result, a request for 8 
560 will result in 9 (a 512-byte window). In that case, providing 8 to 
561 inflateInit2() will result in an error when the zlib header with 9 is 
562 checked against the initialization of inflate(). The remedy is to not use 8 
563 with deflateInit2() with this initialization, or at least in that case use 9 
564 with inflateInit2(). 
565 
566 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 
567 determines the window size. deflate() will then generate raw deflate data 
568 with no zlib header or trailer, and will not compute a check value. 
569 
570 windowBits can also be greater than 15 for optional gzip encoding. Add 
571 16 to windowBits to write a simple gzip header and trailer around the 
572 compressed data instead of a zlib wrapper. The gzip header will have no 
573 file name, no extra data, no comment, no modification time (set to zero), no 
574 header crc, and the operating system will be set to the appropriate value, 
575 if the operating system was determined at compile time. If a gzip stream is 
576 being written, strm->adler is a CRC-32 instead of an Adler-32. 
577 
578 For raw deflate or gzip encoding, a request for a 256-byte window is 
579 rejected as invalid, since only the zlib header provides a means of 
580 transmitting the window size to the decompressor. 
581 
582 The memLevel parameter specifies how much memory should be allocated 
583 for the internal compression state. memLevel=1 uses minimum memory but is 
584 slow and reduces compression ratio; memLevel=9 uses maximum memory for 
585 optimal speed. The default value is 8. See zconf.h for total memory usage 
586 as a function of windowBits and memLevel. 
587 
588 The strategy parameter is used to tune the compression algorithm. Use the 
589 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 
590 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 
591 string match), or Z_RLE to limit match distances to one (run-length 
592 encoding). Filtered data consists mostly of small values with a somewhat 
593 random distribution. In this case, the compression algorithm is tuned to 
594 compress them better. The effect of Z_FILTERED is to force more Huffman 
595 coding and less string matching; it is somewhat intermediate between 
596 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as 
597 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The 
598 strategy parameter only affects the compression ratio but not the 
599 correctness of the compressed output even if it is not set appropriately. 
600 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler 
601 decoder for special applications. 
602 
603 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 
604 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid 
605 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is 
606 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is 
607 set to null if there is no error message. deflateInit2 does not perform any 
608 compression: this will be done by deflate(). 
609*/ 
610 
611ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, 
612 const Bytef *dictionary, 
613 uInt dictLength)); 
614/* 
615 Initializes the compression dictionary from the given byte sequence 
616 without producing any compressed output. When using the zlib format, this 
617 function must be called immediately after deflateInit, deflateInit2 or 
618 deflateReset, and before any call of deflate. When doing raw deflate, this 
619 function must be called either before any call of deflate, or immediately 
620 after the completion of a deflate block, i.e. after all input has been 
621 consumed and all output has been delivered when using any of the flush 
622 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The 
623 compressor and decompressor must use exactly the same dictionary (see 
624 inflateSetDictionary). 
625 
626 The dictionary should consist of strings (byte sequences) that are likely 
627 to be encountered later in the data to be compressed, with the most commonly 
628 used strings preferably put towards the end of the dictionary. Using a 
629 dictionary is most useful when the data to be compressed is short and can be 
630 predicted with good accuracy; the data can then be compressed better than 
631 with the default empty dictionary. 
632 
633 Depending on the size of the compression data structures selected by 
634 deflateInit or deflateInit2, a part of the dictionary may in effect be 
635 discarded, for example if the dictionary is larger than the window size 
636 provided in deflateInit or deflateInit2. Thus the strings most likely to be 
637 useful should be put at the end of the dictionary, not at the front. In 
638 addition, the current implementation of deflate will use at most the window 
639 size minus 262 bytes of the provided dictionary. 
640 
641 Upon return of this function, strm->adler is set to the Adler-32 value 
642 of the dictionary; the decompressor may later use this value to determine 
643 which dictionary has been used by the compressor. (The Adler-32 value 
644 applies to the whole dictionary even if only a subset of the dictionary is 
645 actually used by the compressor.) If a raw deflate was requested, then the 
646 Adler-32 value is not computed and strm->adler is not set. 
647 
648 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 
649 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 
650 inconsistent (for example if deflate has already been called for this stream 
651 or if not at a block boundary for raw deflate). deflateSetDictionary does 
652 not perform any compression: this will be done by deflate(). 
653*/ 
654 
655ZEXTERN int ZEXPORT deflateGetDictionary OF((z_streamp strm, 
656 Bytef *dictionary, 
657 uInt *dictLength)); 
658/* 
659 Returns the sliding dictionary being maintained by deflate. dictLength is 
660 set to the number of bytes in the dictionary, and that many bytes are copied 
661 to dictionary. dictionary must have enough space, where 32768 bytes is 
662 always enough. If deflateGetDictionary() is called with dictionary equal to 
663 Z_NULL, then only the dictionary length is returned, and nothing is copied. 
664 Similary, if dictLength is Z_NULL, then it is not set. 
665 
666 deflateGetDictionary() may return a length less than the window size, even 
667 when more than the window size in input has been provided. It may return up 
668 to 258 bytes less in that case, due to how zlib's implementation of deflate 
669 manages the sliding window and lookahead for matches, where matches can be 
670 up to 258 bytes long. If the application needs the last window-size bytes of 
671 input, then that would need to be saved by the application outside of zlib. 
672 
673 deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 
674 stream state is inconsistent. 
675*/ 
676 
677ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, 
678 z_streamp source)); 
679/* 
680 Sets the destination stream as a complete copy of the source stream. 
681 
682 This function can be useful when several compression strategies will be 
683 tried, for example when there are several ways of pre-processing the input 
684 data with a filter. The streams that will be discarded should then be freed 
685 by calling deflateEnd. Note that deflateCopy duplicates the internal 
686 compression state which can be quite large, so this strategy is slow and can 
687 consume lots of memory. 
688 
689 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 
690 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 
691 (such as zalloc being Z_NULL). msg is left unchanged in both source and 
692 destination. 
693*/ 
694 
695ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); 
696/* 
697 This function is equivalent to deflateEnd followed by deflateInit, but 
698 does not free and reallocate the internal compression state. The stream 
699 will leave the compression level and any other attributes that may have been 
700 set unchanged. 
701 
702 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 
703 stream state was inconsistent (such as zalloc or state being Z_NULL). 
704*/ 
705 
706ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, 
707 int level, 
708 int strategy)); 
709/* 
710 Dynamically update the compression level and compression strategy. The 
711 interpretation of level and strategy is as in deflateInit2(). This can be 
712 used to switch between compression and straight copy of the input data, or 
713 to switch to a different kind of input data requiring a different strategy. 
714 If the compression approach (which is a function of the level) or the 
715 strategy is changed, and if there have been any deflate() calls since the 
716 state was initialized or reset, then the input available so far is 
717 compressed with the old level and strategy using deflate(strm, Z_BLOCK). 
718 There are three approaches for the compression levels 0, 1..3, and 4..9 
719 respectively. The new level and strategy will take effect at the next call 
720 of deflate(). 
721 
722 If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does 
723 not have enough output space to complete, then the parameter change will not 
724 take effect. In this case, deflateParams() can be called again with the 
725 same parameters and more output space to try again. 
726 
727 In order to assure a change in the parameters on the first try, the 
728 deflate stream should be flushed using deflate() with Z_BLOCK or other flush 
729 request until strm.avail_out is not zero, before calling deflateParams(). 
730 Then no more input data should be provided before the deflateParams() call. 
731 If this is done, the old level and strategy will be applied to the data 
732 compressed before deflateParams(), and the new level and strategy will be 
733 applied to the the data compressed after deflateParams(). 
734 
735 deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream 
736 state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if 
737 there was not enough output space to complete the compression of the 
738 available input data before a change in the strategy or approach. Note that 
739 in the case of a Z_BUF_ERROR, the parameters are not changed. A return 
740 value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be 
741 retried with more output space. 
742*/ 
743 
744ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, 
745 int good_length, 
746 int max_lazy, 
747 int nice_length, 
748 int max_chain)); 
749/* 
750 Fine tune deflate's internal compression parameters. This should only be 
751 used by someone who understands the algorithm used by zlib's deflate for 
752 searching for the best matching string, and even then only by the most 
753 fanatic optimizer trying to squeeze out the last compressed bit for their 
754 specific input data. Read the deflate.c source code for the meaning of the 
755 max_lazy, good_length, nice_length, and max_chain parameters. 
756 
757 deflateTune() can be called after deflateInit() or deflateInit2(), and 
758 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 
759 */ 
760 
761ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, 
762 uLong sourceLen)); 
763/* 
764 deflateBound() returns an upper bound on the compressed size after 
765 deflation of sourceLen bytes. It must be called after deflateInit() or 
766 deflateInit2(), and after deflateSetHeader(), if used. This would be used 
767 to allocate an output buffer for deflation in a single pass, and so would be 
768 called before deflate(). If that first deflate() call is provided the 
769 sourceLen input bytes, an output buffer allocated to the size returned by 
770 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed 
771 to return Z_STREAM_END. Note that it is possible for the compressed size to 
772 be larger than the value returned by deflateBound() if flush options other 
773 than Z_FINISH or Z_NO_FLUSH are used. 
774*/ 
775 
776ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm, 
777 unsigned *pending, 
778 int *bits)); 
779/* 
780 deflatePending() returns the number of bytes and bits of output that have 
781 been generated, but not yet provided in the available output. The bytes not 
782 provided would be due to the available output space having being consumed. 
783 The number of bits of output not provided are between 0 and 7, where they 
784 await more bits to join them in order to fill out a full byte. If pending 
785 or bits are Z_NULL, then those values are not set. 
786 
787 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source 
788 stream state was inconsistent. 
789 */ 
790 
791ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, 
792 int bits, 
793 int value)); 
794/* 
795 deflatePrime() inserts bits in the deflate output stream. The intent 
796 is that this function is used to start off the deflate output with the bits 
797 leftover from a previous deflate stream when appending to it. As such, this 
798 function can only be used for raw deflate, and must be used before the first 
799 deflate() call after a deflateInit2() or deflateReset(). bits must be less 
800 than or equal to 16, and that many of the least significant bits of value 
801 will be inserted in the output. 
802 
803 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough 
804 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the 
805 source stream state was inconsistent. 
806*/ 
807 
808ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, 
809 gz_headerp head)); 
810/* 
811 deflateSetHeader() provides gzip header information for when a gzip 
812 stream is requested by deflateInit2(). deflateSetHeader() may be called 
813 after deflateInit2() or deflateReset() and before the first call of 
814 deflate(). The text, time, os, extra field, name, and comment information 
815 in the provided gz_header structure are written to the gzip header (xflag is 
816 ignored -- the extra flags are set according to the compression level). The 
817 caller must assure that, if not Z_NULL, name and comment are terminated with 
818 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 
819 available there. If hcrc is true, a gzip header crc is included. Note that 
820 the current versions of the command-line version of gzip (up through version 
821 1.3.x) do not support header crc's, and will report that it is a "multi-part 
822 gzip file" and give up. 
823 
824 If deflateSetHeader is not used, the default gzip header has text false, 
825 the time set to zero, and os set to 255, with no extra, name, or comment 
826 fields. The gzip header is returned to the default state by deflateReset(). 
827 
828 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 
829 stream state was inconsistent. 
830*/ 
831 
832/* 
833ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, 
834 int windowBits)); 
835 
836 This is another version of inflateInit with an extra parameter. The 
837 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 
838 before by the caller. 
839 
840 The windowBits parameter is the base two logarithm of the maximum window 
841 size (the size of the history buffer). It should be in the range 8..15 for 
842 this version of the library. The default value is 15 if inflateInit is used 
843 instead. windowBits must be greater than or equal to the windowBits value 
844 provided to deflateInit2() while compressing, or it must be equal to 15 if 
845 deflateInit2() was not used. If a compressed stream with a larger window 
846 size is given as input, inflate() will return with the error code 
847 Z_DATA_ERROR instead of trying to allocate a larger window. 
848 
849 windowBits can also be zero to request that inflate use the window size in 
850 the zlib header of the compressed stream. 
851 
852 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 
853 determines the window size. inflate() will then process raw deflate data, 
854 not looking for a zlib or gzip header, not generating a check value, and not 
855 looking for any check values for comparison at the end of the stream. This 
856 is for use with other formats that use the deflate compressed data format 
857 such as zip. Those formats provide their own check values. If a custom 
858 format is developed using the raw deflate format for compressed data, it is 
859 recommended that a check value such as an Adler-32 or a CRC-32 be applied to 
860 the uncompressed data as is done in the zlib, gzip, and zip formats. For 
861 most applications, the zlib format should be used as is. Note that comments 
862 above on the use in deflateInit2() applies to the magnitude of windowBits. 
863 
864 windowBits can also be greater than 15 for optional gzip decoding. Add 
865 32 to windowBits to enable zlib and gzip decoding with automatic header 
866 detection, or add 16 to decode only the gzip format (the zlib format will 
867 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a 
868 CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see 
869 below), inflate() will not automatically decode concatenated gzip streams. 
870 inflate() will return Z_STREAM_END at the end of the gzip stream. The state 
871 would need to be reset to continue decoding a subsequent gzip stream. 
872 
873 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 
874 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 
875 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 
876 invalid, such as a null pointer to the structure. msg is set to null if 
877 there is no error message. inflateInit2 does not perform any decompression 
878 apart from possibly reading the zlib header if present: actual decompression 
879 will be done by inflate(). (So next_in and avail_in may be modified, but 
880 next_out and avail_out are unused and unchanged.) The current implementation 
881 of inflateInit2() does not process any header information -- that is 
882 deferred until inflate() is called. 
883*/ 
884 
885ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, 
886 const Bytef *dictionary, 
887 uInt dictLength)); 
888/* 
889 Initializes the decompression dictionary from the given uncompressed byte 
890 sequence. This function must be called immediately after a call of inflate, 
891 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 
892 can be determined from the Adler-32 value returned by that call of inflate. 
893 The compressor and decompressor must use exactly the same dictionary (see 
894 deflateSetDictionary). For raw inflate, this function can be called at any 
895 time to set the dictionary. If the provided dictionary is smaller than the 
896 window and there is already data in the window, then the provided dictionary 
897 will amend what's there. The application must insure that the dictionary 
898 that was used for compression is provided. 
899 
900 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 
901 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 
902 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 
903 expected one (incorrect Adler-32 value). inflateSetDictionary does not 
904 perform any decompression: this will be done by subsequent calls of 
905 inflate(). 
906*/ 
907 
908ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm, 
909 Bytef *dictionary, 
910 uInt *dictLength)); 
911/* 
912 Returns the sliding dictionary being maintained by inflate. dictLength is 
913 set to the number of bytes in the dictionary, and that many bytes are copied 
914 to dictionary. dictionary must have enough space, where 32768 bytes is 
915 always enough. If inflateGetDictionary() is called with dictionary equal to 
916 Z_NULL, then only the dictionary length is returned, and nothing is copied. 
917 Similary, if dictLength is Z_NULL, then it is not set. 
918 
919 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 
920 stream state is inconsistent. 
921*/ 
922 
923ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); 
924/* 
925 Skips invalid compressed data until a possible full flush point (see above 
926 for the description of deflate with Z_FULL_FLUSH) can be found, or until all 
927 available input is skipped. No output is provided. 
928 
929 inflateSync searches for a 00 00 FF FF pattern in the compressed data. 
930 All full flush points have this pattern, but not all occurrences of this 
931 pattern are full flush points. 
932 
933 inflateSync returns Z_OK if a possible full flush point has been found, 
934 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point 
935 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. 
936 In the success case, the application may save the current current value of 
937 total_in which indicates where valid compressed data was found. In the 
938 error case, the application may repeatedly call inflateSync, providing more 
939 input each time, until success or end of the input data. 
940*/ 
941 
942ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, 
943 z_streamp source)); 
944/* 
945 Sets the destination stream as a complete copy of the source stream. 
946 
947 This function can be useful when randomly accessing a large stream. The 
948 first pass through the stream can periodically record the inflate state, 
949 allowing restarting inflate at those points when randomly accessing the 
950 stream. 
951 
952 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 
953 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 
954 (such as zalloc being Z_NULL). msg is left unchanged in both source and 
955 destination. 
956*/ 
957 
958ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); 
959/* 
960 This function is equivalent to inflateEnd followed by inflateInit, 
961 but does not free and reallocate the internal decompression state. The 
962 stream will keep attributes that may have been set by inflateInit2. 
963 
964 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 
965 stream state was inconsistent (such as zalloc or state being Z_NULL). 
966*/ 
967 
968ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm, 
969 int windowBits)); 
970/* 
971 This function is the same as inflateReset, but it also permits changing 
972 the wrap and window size requests. The windowBits parameter is interpreted 
973 the same as it is for inflateInit2. If the window size is changed, then the 
974 memory allocated for the window is freed, and the window will be reallocated 
975 by inflate() if needed. 
976 
977 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 
978 stream state was inconsistent (such as zalloc or state being Z_NULL), or if 
979 the windowBits parameter is invalid. 
980*/ 
981 
982ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, 
983 int bits, 
984 int value)); 
985/* 
986 This function inserts bits in the inflate input stream. The intent is 
987 that this function is used to start inflating at a bit position in the 
988 middle of a byte. The provided bits will be used before any bytes are used 
989 from next_in. This function should only be used with raw inflate, and 
990 should be used before the first inflate() call after inflateInit2() or 
991 inflateReset(). bits must be less than or equal to 16, and that many of the 
992 least significant bits of value will be inserted in the input. 
993 
994 If bits is negative, then the input stream bit buffer is emptied. Then 
995 inflatePrime() can be called again to put bits in the buffer. This is used 
996 to clear out bits leftover after feeding inflate a block description prior 
997 to feeding inflate codes. 
998 
999 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 
1000 stream state was inconsistent. 
1001*/ 
1002 
1003ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); 
1004/* 
1005 This function returns two values, one in the lower 16 bits of the return 
1006 value, and the other in the remaining upper bits, obtained by shifting the 
1007 return value down 16 bits. If the upper value is -1 and the lower value is 
1008 zero, then inflate() is currently decoding information outside of a block. 
1009 If the upper value is -1 and the lower value is non-zero, then inflate is in 
1010 the middle of a stored block, with the lower value equaling the number of 
1011 bytes from the input remaining to copy. If the upper value is not -1, then 
1012 it is the number of bits back from the current bit position in the input of 
1013 the code (literal or length/distance pair) currently being processed. In 
1014 that case the lower value is the number of bytes already emitted for that 
1015 code. 
1016 
1017 A code is being processed if inflate is waiting for more input to complete 
1018 decoding of the code, or if it has completed decoding but is waiting for 
1019 more output space to write the literal or match data. 
1020 
1021 inflateMark() is used to mark locations in the input data for random 
1022 access, which may be at bit positions, and to note those cases where the 
1023 output of a code may span boundaries of random access blocks. The current 
1024 location in the input stream can be determined from avail_in and data_type 
1025 as noted in the description for the Z_BLOCK flush parameter for inflate. 
1026 
1027 inflateMark returns the value noted above, or -65536 if the provided 
1028 source stream state was inconsistent. 
1029*/ 
1030 
1031ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, 
1032 gz_headerp head)); 
1033/* 
1034 inflateGetHeader() requests that gzip header information be stored in the 
1035 provided gz_header structure. inflateGetHeader() may be called after 
1036 inflateInit2() or inflateReset(), and before the first call of inflate(). 
1037 As inflate() processes the gzip stream, head->done is zero until the header 
1038 is completed, at which time head->done is set to one. If a zlib stream is 
1039 being decoded, then head->done is set to -1 to indicate that there will be 
1040 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 
1041 used to force inflate() to return immediately after header processing is 
1042 complete and before any actual data is decompressed. 
1043 
1044 The text, time, xflags, and os fields are filled in with the gzip header 
1045 contents. hcrc is set to true if there is a header CRC. (The header CRC 
1046 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 
1047 contains the maximum number of bytes to write to extra. Once done is true, 
1048 extra_len contains the actual extra field length, and extra contains the 
1049 extra field, or that field truncated if extra_max is less than extra_len. 
1050 If name is not Z_NULL, then up to name_max characters are written there, 
1051 terminated with a zero unless the length is greater than name_max. If 
1052 comment is not Z_NULL, then up to comm_max characters are written there, 
1053 terminated with a zero unless the length is greater than comm_max. When any 
1054 of extra, name, or comment are not Z_NULL and the respective field is not 
1055 present in the header, then that field is set to Z_NULL to signal its 
1056 absence. This allows the use of deflateSetHeader() with the returned 
1057 structure to duplicate the header. However if those fields are set to 
1058 allocated memory, then the application will need to save those pointers 
1059 elsewhere so that they can be eventually freed. 
1060 
1061 If inflateGetHeader is not used, then the header information is simply 
1062 discarded. The header is always checked for validity, including the header 
1063 CRC if present. inflateReset() will reset the process to discard the header 
1064 information. The application would need to call inflateGetHeader() again to 
1065 retrieve the header from the next gzip stream. 
1066 
1067 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 
1068 stream state was inconsistent. 
1069*/ 
1070 
1071/* 
1072ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, 
1073 unsigned char FAR *window)); 
1074 
1075 Initialize the internal stream state for decompression using inflateBack() 
1076 calls. The fields zalloc, zfree and opaque in strm must be initialized 
1077 before the call. If zalloc and zfree are Z_NULL, then the default library- 
1078 derived memory allocation routines are used. windowBits is the base two 
1079 logarithm of the window size, in the range 8..15. window is a caller 
1080 supplied buffer of that size. Except for special applications where it is 
1081 assured that deflate was used with small window sizes, windowBits must be 15 
1082 and a 32K byte window must be supplied to be able to decompress general 
1083 deflate streams. 
1084 
1085 See inflateBack() for the usage of these routines. 
1086 
1087 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 
1088 the parameters are invalid, Z_MEM_ERROR if the internal state could not be 
1089 allocated, or Z_VERSION_ERROR if the version of the library does not match 
1090 the version of the header file. 
1091*/ 
1092 
1093typedef unsigned (*in_func) OF((void FAR *, 
1094 z_const unsigned char FAR * FAR *)); 
1095typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); 
1096 
1097ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, 
1098 in_func in, void FAR *in_desc, 
1099 out_func out, void FAR *out_desc)); 
1100/* 
1101 inflateBack() does a raw inflate with a single call using a call-back 
1102 interface for input and output. This is potentially more efficient than 
1103 inflate() for file i/o applications, in that it avoids copying between the 
1104 output and the sliding window by simply making the window itself the output 
1105 buffer. inflate() can be faster on modern CPUs when used with large 
1106 buffers. inflateBack() trusts the application to not change the output 
1107 buffer passed by the output function, at least until inflateBack() returns. 
1108 
1109 inflateBackInit() must be called first to allocate the internal state 
1110 and to initialize the state with the user-provided window buffer. 
1111 inflateBack() may then be used multiple times to inflate a complete, raw 
1112 deflate stream with each call. inflateBackEnd() is then called to free the 
1113 allocated state. 
1114 
1115 A raw deflate stream is one with no zlib or gzip header or trailer. 
1116 This routine would normally be used in a utility that reads zip or gzip 
1117 files and writes out uncompressed files. The utility would decode the 
1118 header and process the trailer on its own, hence this routine expects only 
1119 the raw deflate stream to decompress. This is different from the default 
1120 behavior of inflate(), which expects a zlib header and trailer around the 
1121 deflate stream. 
1122 
1123 inflateBack() uses two subroutines supplied by the caller that are then 
1124 called by inflateBack() for input and output. inflateBack() calls those 
1125 routines until it reads a complete deflate stream and writes out all of the 
1126 uncompressed data, or until it encounters an error. The function's 
1127 parameters and return types are defined above in the in_func and out_func 
1128 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 
1129 number of bytes of provided input, and a pointer to that input in buf. If 
1130 there is no input available, in() must return zero -- buf is ignored in that 
1131 case -- and inflateBack() will return a buffer error. inflateBack() will 
1132 call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. 
1133 out() should return zero on success, or non-zero on failure. If out() 
1134 returns non-zero, inflateBack() will return with an error. Neither in() nor 
1135 out() are permitted to change the contents of the window provided to 
1136 inflateBackInit(), which is also the buffer that out() uses to write from. 
1137 The length written by out() will be at most the window size. Any non-zero 
1138 amount of input may be provided by in(). 
1139 
1140 For convenience, inflateBack() can be provided input on the first call by 
1141 setting strm->next_in and strm->avail_in. If that input is exhausted, then 
1142 in() will be called. Therefore strm->next_in must be initialized before 
1143 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 
1144 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 
1145 must also be initialized, and then if strm->avail_in is not zero, input will 
1146 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 
1147 
1148 The in_desc and out_desc parameters of inflateBack() is passed as the 
1149 first parameter of in() and out() respectively when they are called. These 
1150 descriptors can be optionally used to pass any information that the caller- 
1151 supplied in() and out() functions need to do their job. 
1152 
1153 On return, inflateBack() will set strm->next_in and strm->avail_in to 
1154 pass back any unused input that was provided by the last in() call. The 
1155 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 
1156 if in() or out() returned an error, Z_DATA_ERROR if there was a format error 
1157 in the deflate stream (in which case strm->msg is set to indicate the nature 
1158 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. 
1159 In the case of Z_BUF_ERROR, an input or output error can be distinguished 
1160 using strm->next_in which will be Z_NULL only if in() returned an error. If 
1161 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning 
1162 non-zero. (in() will always be called before out(), so strm->next_in is 
1163 assured to be defined if out() returns non-zero.) Note that inflateBack() 
1164 cannot return Z_OK. 
1165*/ 
1166 
1167ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); 
1168/* 
1169 All memory allocated by inflateBackInit() is freed. 
1170 
1171 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 
1172 state was inconsistent. 
1173*/ 
1174 
1175ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); 
1176/* Return flags indicating compile-time options. 
1177 
1178 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 
1179 1.0: size of uInt 
1180 3.2: size of uLong 
1181 5.4: size of voidpf (pointer) 
1182 7.6: size of z_off_t 
1183 
1184 Compiler, assembler, and debug options: 
1185 8: ZLIB_DEBUG 
1186 9: ASMV or ASMINF -- use ASM code 
1187 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 
1188 11: 0 (reserved) 
1189 
1190 One-time table building (smaller code, but not thread-safe if true): 
1191 12: BUILDFIXED -- build static block decoding tables when needed 
1192 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 
1193 14,15: 0 (reserved) 
1194 
1195 Library content (indicates missing functionality): 
1196 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 
1197 deflate code when not needed) 
1198 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 
1199 and decode gzip streams (to avoid linking crc code) 
1200 18-19: 0 (reserved) 
1201 
1202 Operation variations (changes in library functionality): 
1203 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 
1204 21: FASTEST -- deflate algorithm with only one, lowest compression level 
1205 22,23: 0 (reserved) 
1206 
1207 The sprintf variant used by gzprintf (zero is best): 
1208 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 
1209 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 
1210 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 
1211 
1212 Remainder: 
1213 27-31: 0 (reserved) 
1214 */ 
1215 
1216#ifndef Z_SOLO 
1217 
1218 /* utility functions */ 
1219 
1220/* 
1221 The following utility functions are implemented on top of the basic 
1222 stream-oriented functions. To simplify the interface, some default options 
1223 are assumed (compression level and memory usage, standard memory allocation 
1224 functions). The source code of these utility functions can be modified if 
1225 you need special options. 
1226*/ 
1227 
1228ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, 
1229 const Bytef *source, uLong sourceLen)); 
1230/* 
1231 Compresses the source buffer into the destination buffer. sourceLen is 
1232 the byte length of the source buffer. Upon entry, destLen is the total size 
1233 of the destination buffer, which must be at least the value returned by 
1234 compressBound(sourceLen). Upon exit, destLen is the actual size of the 
1235 compressed data. compress() is equivalent to compress2() with a level 
1236 parameter of Z_DEFAULT_COMPRESSION. 
1237 
1238 compress returns Z_OK if success, Z_MEM_ERROR if there was not 
1239 enough memory, Z_BUF_ERROR if there was not enough room in the output 
1240 buffer. 
1241*/ 
1242 
1243ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, 
1244 const Bytef *source, uLong sourceLen, 
1245 int level)); 
1246/* 
1247 Compresses the source buffer into the destination buffer. The level 
1248 parameter has the same meaning as in deflateInit. sourceLen is the byte 
1249 length of the source buffer. Upon entry, destLen is the total size of the 
1250 destination buffer, which must be at least the value returned by 
1251 compressBound(sourceLen). Upon exit, destLen is the actual size of the 
1252 compressed data. 
1253 
1254 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 
1255 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 
1256 Z_STREAM_ERROR if the level parameter is invalid. 
1257*/ 
1258 
1259ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); 
1260/* 
1261 compressBound() returns an upper bound on the compressed size after 
1262 compress() or compress2() on sourceLen bytes. It would be used before a 
1263 compress() or compress2() call to allocate the destination buffer. 
1264*/ 
1265 
1266ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, 
1267 const Bytef *source, uLong sourceLen)); 
1268/* 
1269 Decompresses the source buffer into the destination buffer. sourceLen is 
1270 the byte length of the source buffer. Upon entry, destLen is the total size 
1271 of the destination buffer, which must be large enough to hold the entire 
1272 uncompressed data. (The size of the uncompressed data must have been saved 
1273 previously by the compressor and transmitted to the decompressor by some 
1274 mechanism outside the scope of this compression library.) Upon exit, destLen 
1275 is the actual size of the uncompressed data. 
1276 
1277 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 
1278 enough memory, Z_BUF_ERROR if there was not enough room in the output 
1279 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In 
1280 the case where there is not enough room, uncompress() will fill the output 
1281 buffer with the uncompressed data up to that point. 
1282*/ 
1283 
1284ZEXTERN int ZEXPORT uncompress2 OF((Bytef *dest, uLongf *destLen, 
1285 const Bytef *source, uLong *sourceLen)); 
1286/* 
1287 Same as uncompress, except that sourceLen is a pointer, where the 
1288 length of the source is *sourceLen. On return, *sourceLen is the number of 
1289 source bytes consumed. 
1290*/ 
1291 
1292 /* gzip file access functions */ 
1293 
1294/* 
1295 This library supports reading and writing files in gzip (.gz) format with 
1296 an interface similar to that of stdio, using the functions that start with 
1297 "gz". The gzip format is different from the zlib format. gzip is a gzip 
1298 wrapper, documented in RFC 1952, wrapped around a deflate stream. 
1299*/ 
1300 
1301typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ 
1302 
1303/* 
1304ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); 
1305 
1306 Opens a gzip (.gz) file for reading or writing. The mode parameter is as 
1307 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or 
1308 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only 
1309 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F' 
1310 for fixed code compression as in "wb9F". (See the description of 
1311 deflateInit2 for more information about the strategy parameter.) 'T' will 
1312 request transparent writing or appending with no compression and not using 
1313 the gzip format. 
1314 
1315 "a" can be used instead of "w" to request that the gzip stream that will 
1316 be written be appended to the file. "+" will result in an error, since 
1317 reading and writing to the same gzip file is not supported. The addition of 
1318 "x" when writing will create the file exclusively, which fails if the file 
1319 already exists. On systems that support it, the addition of "e" when 
1320 reading or writing will set the flag to close the file on an execve() call. 
1321 
1322 These functions, as well as gzip, will read and decode a sequence of gzip 
1323 streams in a file. The append function of gzopen() can be used to create 
1324 such a file. (Also see gzflush() for another way to do this.) When 
1325 appending, gzopen does not test whether the file begins with a gzip stream, 
1326 nor does it look for the end of the gzip streams to begin appending. gzopen 
1327 will simply append a gzip stream to the existing file. 
1328 
1329 gzopen can be used to read a file which is not in gzip format; in this 
1330 case gzread will directly read from the file without decompression. When 
1331 reading, this will be detected automatically by looking for the magic two- 
1332 byte gzip header. 
1333 
1334 gzopen returns NULL if the file could not be opened, if there was 
1335 insufficient memory to allocate the gzFile state, or if an invalid mode was 
1336 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). 
1337 errno can be checked to determine if the reason gzopen failed was that the 
1338 file could not be opened. 
1339*/ 
1340 
1341ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); 
1342/* 
1343 gzdopen associates a gzFile with the file descriptor fd. File descriptors 
1344 are obtained from calls like open, dup, creat, pipe or fileno (if the file 
1345 has been previously opened with fopen). The mode parameter is as in gzopen. 
1346 
1347 The next call of gzclose on the returned gzFile will also close the file 
1348 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor 
1349 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, 
1350 mode);. The duplicated descriptor should be saved to avoid a leak, since 
1351 gzdopen does not close fd if it fails. If you are using fileno() to get the 
1352 file descriptor from a FILE *, then you will have to use dup() to avoid 
1353 double-close()ing the file descriptor. Both gzclose() and fclose() will 
1354 close the associated file descriptor, so they need to have different file 
1355 descriptors. 
1356 
1357 gzdopen returns NULL if there was insufficient memory to allocate the 
1358 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not 
1359 provided, or '+' was provided), or if fd is -1. The file descriptor is not 
1360 used until the next gz* read, write, seek, or close operation, so gzdopen 
1361 will not detect if fd is invalid (unless fd is -1). 
1362*/ 
1363 
1364ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size)); 
1365/* 
1366 Set the internal buffer size used by this library's functions. The 
1367 default buffer size is 8192 bytes. This function must be called after 
1368 gzopen() or gzdopen(), and before any other calls that read or write the 
1369 file. The buffer memory allocation is always deferred to the first read or 
1370 write. Three times that size in buffer space is allocated. A larger buffer 
1371 size of, for example, 64K or 128K bytes will noticeably increase the speed 
1372 of decompression (reading). 
1373 
1374 The new buffer size also affects the maximum length for gzprintf(). 
1375 
1376 gzbuffer() returns 0 on success, or -1 on failure, such as being called 
1377 too late. 
1378*/ 
1379 
1380ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); 
1381/* 
1382 Dynamically update the compression level or strategy. See the description 
1383 of deflateInit2 for the meaning of these parameters. Previously provided 
1384 data is flushed before the parameter change. 
1385 
1386 gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not 
1387 opened for writing, Z_ERRNO if there is an error writing the flushed data, 
1388 or Z_MEM_ERROR if there is a memory allocation error. 
1389*/ 
1390 
1391ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 
1392/* 
1393 Reads the given number of uncompressed bytes from the compressed file. If 
1394 the input file is not in gzip format, gzread copies the given number of 
1395 bytes into the buffer directly from the file. 
1396 
1397 After reaching the end of a gzip stream in the input, gzread will continue 
1398 to read, looking for another gzip stream. Any number of gzip streams may be 
1399 concatenated in the input file, and will all be decompressed by gzread(). 
1400 If something other than a gzip stream is encountered after a gzip stream, 
1401 that remaining trailing garbage is ignored (and no error is returned). 
1402 
1403 gzread can be used to read a gzip file that is being concurrently written. 
1404 Upon reaching the end of the input, gzread will return with the available 
1405 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then 
1406 gzclearerr can be used to clear the end of file indicator in order to permit 
1407 gzread to be tried again. Z_OK indicates that a gzip stream was completed 
1408 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the 
1409 middle of a gzip stream. Note that gzread does not return -1 in the event 
1410 of an incomplete gzip stream. This error is deferred until gzclose(), which 
1411 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip 
1412 stream. Alternatively, gzerror can be used before gzclose to detect this 
1413 case. 
1414 
1415 gzread returns the number of uncompressed bytes actually read, less than 
1416 len for end of file, or -1 for error. If len is too large to fit in an int, 
1417 then nothing is read, -1 is returned, and the error state is set to 
1418 Z_STREAM_ERROR. 
1419*/ 
1420 
1421ZEXTERN z_size_t ZEXPORT gzfread OF((voidp buf, z_size_t size, z_size_t nitems, 
1422 gzFile file)); 
1423/* 
1424 Read up to nitems items of size size from file to buf, otherwise operating 
1425 as gzread() does. This duplicates the interface of stdio's fread(), with 
1426 size_t request and return types. If the library defines size_t, then 
1427 z_size_t is identical to size_t. If not, then z_size_t is an unsigned 
1428 integer type that can contain a pointer. 
1429 
1430 gzfread() returns the number of full items read of size size, or zero if 
1431 the end of the file was reached and a full item could not be read, or if 
1432 there was an error. gzerror() must be consulted if zero is returned in 
1433 order to determine if there was an error. If the multiplication of size and 
1434 nitems overflows, i.e. the product does not fit in a z_size_t, then nothing 
1435 is read, zero is returned, and the error state is set to Z_STREAM_ERROR. 
1436 
1437 In the event that the end of file is reached and only a partial item is 
1438 available at the end, i.e. the remaining uncompressed data length is not a 
1439 multiple of size, then the final partial item is nevetheless read into buf 
1440 and the end-of-file flag is set. The length of the partial item read is not 
1441 provided, but could be inferred from the result of gztell(). This behavior 
1442 is the same as the behavior of fread() implementations in common libraries, 
1443 but it prevents the direct use of gzfread() to read a concurrently written 
1444 file, reseting and retrying on end-of-file, when size is not 1. 
1445*/ 
1446 
1447ZEXTERN int ZEXPORT gzwrite OF((gzFile file, 
1448 voidpc buf, unsigned len)); 
1449/* 
1450 Writes the given number of uncompressed bytes into the compressed file. 
1451 gzwrite returns the number of uncompressed bytes written or 0 in case of 
1452 error. 
1453*/ 
1454 
1455ZEXTERN z_size_t ZEXPORT gzfwrite OF((voidpc buf, z_size_t size, 
1456 z_size_t nitems, gzFile file)); 
1457/* 
1458 gzfwrite() writes nitems items of size size from buf to file, duplicating 
1459 the interface of stdio's fwrite(), with size_t request and return types. If 
1460 the library defines size_t, then z_size_t is identical to size_t. If not, 
1461 then z_size_t is an unsigned integer type that can contain a pointer. 
1462 
1463 gzfwrite() returns the number of full items written of size size, or zero 
1464 if there was an error. If the multiplication of size and nitems overflows, 
1465 i.e. the product does not fit in a z_size_t, then nothing is written, zero 
1466 is returned, and the error state is set to Z_STREAM_ERROR. 
1467*/ 
1468 
1469ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...)); 
1470/* 
1471 Converts, formats, and writes the arguments to the compressed file under 
1472 control of the format string, as in fprintf. gzprintf returns the number of 
1473 uncompressed bytes actually written, or a negative zlib error code in case 
1474 of error. The number of uncompressed bytes written is limited to 8191, or 
1475 one less than the buffer size given to gzbuffer(). The caller should assure 
1476 that this limit is not exceeded. If it is exceeded, then gzprintf() will 
1477 return an error (0) with nothing written. In this case, there may also be a 
1478 buffer overflow with unpredictable consequences, which is possible only if 
1479 zlib was compiled with the insecure functions sprintf() or vsprintf() 
1480 because the secure snprintf() or vsnprintf() functions were not available. 
1481 This can be determined using zlibCompileFlags(). 
1482*/ 
1483 
1484ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); 
1485/* 
1486 Writes the given null-terminated string to the compressed file, excluding 
1487 the terminating null character. 
1488 
1489 gzputs returns the number of characters written, or -1 in case of error. 
1490*/ 
1491 
1492ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); 
1493/* 
1494 Reads bytes from the compressed file until len-1 characters are read, or a 
1495 newline character is read and transferred to buf, or an end-of-file 
1496 condition is encountered. If any characters are read or if len == 1, the 
1497 string is terminated with a null character. If no characters are read due 
1498 to an end-of-file or len < 1, then the buffer is left untouched. 
1499 
1500 gzgets returns buf which is a null-terminated string, or it returns NULL 
1501 for end-of-file or in case of error. If there was an error, the contents at 
1502 buf are indeterminate. 
1503*/ 
1504 
1505ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); 
1506/* 
1507 Writes c, converted to an unsigned char, into the compressed file. gzputc 
1508 returns the value that was written, or -1 in case of error. 
1509*/ 
1510 
1511ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); 
1512/* 
1513 Reads one byte from the compressed file. gzgetc returns this byte or -1 
1514 in case of end of file or error. This is implemented as a macro for speed. 
1515 As such, it does not do all of the checking the other functions do. I.e. 
1516 it does not check to see if file is NULL, nor whether the structure file 
1517 points to has been clobbered or not. 
1518*/ 
1519 
1520ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); 
1521/* 
1522 Push one character back onto the stream to be read as the first character 
1523 on the next read. At least one character of push-back is allowed. 
1524 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will 
1525 fail if c is -1, and may fail if a character has been pushed but not read 
1526 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the 
1527 output buffer size of pushed characters is allowed. (See gzbuffer above.) 
1528 The pushed character will be discarded if the stream is repositioned with 
1529 gzseek() or gzrewind(). 
1530*/ 
1531 
1532ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); 
1533/* 
1534 Flushes all pending output into the compressed file. The parameter flush 
1535 is as in the deflate() function. The return value is the zlib error number 
1536 (see function gzerror below). gzflush is only permitted when writing. 
1537 
1538 If the flush parameter is Z_FINISH, the remaining data is written and the 
1539 gzip stream is completed in the output. If gzwrite() is called again, a new 
1540 gzip stream will be started in the output. gzread() is able to read such 
1541 concatenated gzip streams. 
1542 
1543 gzflush should be called only when strictly necessary because it will 
1544 degrade compression if called too often. 
1545*/ 
1546 
1547/* 
1548ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, 
1549 z_off_t offset, int whence)); 
1550 
1551 Sets the starting position for the next gzread or gzwrite on the given 
1552 compressed file. The offset represents a number of bytes in the 
1553 uncompressed data stream. The whence parameter is defined as in lseek(2); 
1554 the value SEEK_END is not supported. 
1555 
1556 If the file is opened for reading, this function is emulated but can be 
1557 extremely slow. If the file is opened for writing, only forward seeks are 
1558 supported; gzseek then compresses a sequence of zeroes up to the new 
1559 starting position. 
1560 
1561 gzseek returns the resulting offset location as measured in bytes from 
1562 the beginning of the uncompressed stream, or -1 in case of error, in 
1563 particular if the file is opened for writing and the new starting position 
1564 would be before the current position. 
1565*/ 
1566 
1567ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); 
1568/* 
1569 Rewinds the given file. This function is supported only for reading. 
1570 
1571 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) 
1572*/ 
1573 
1574/* 
1575ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); 
1576 
1577 Returns the starting position for the next gzread or gzwrite on the given 
1578 compressed file. This position represents a number of bytes in the 
1579 uncompressed data stream, and is zero when starting, even if appending or 
1580 reading a gzip stream from the middle of a file using gzdopen(). 
1581 
1582 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 
1583*/ 
1584 
1585/* 
1586ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); 
1587 
1588 Returns the current offset in the file being read or written. This offset 
1589 includes the count of bytes that precede the gzip stream, for example when 
1590 appending or when using gzdopen() for reading. When reading, the offset 
1591 does not include as yet unused buffered input. This information can be used 
1592 for a progress indicator. On error, gzoffset() returns -1. 
1593*/ 
1594 
1595ZEXTERN int ZEXPORT gzeof OF((gzFile file)); 
1596/* 
1597 Returns true (1) if the end-of-file indicator has been set while reading, 
1598 false (0) otherwise. Note that the end-of-file indicator is set only if the 
1599 read tried to go past the end of the input, but came up short. Therefore, 
1600 just like feof(), gzeof() may return false even if there is no more data to 
1601 read, in the event that the last read request was for the exact number of 
1602 bytes remaining in the input file. This will happen if the input file size 
1603 is an exact multiple of the buffer size. 
1604 
1605 If gzeof() returns true, then the read functions will return no more data, 
1606 unless the end-of-file indicator is reset by gzclearerr() and the input file 
1607 has grown since the previous end of file was detected. 
1608*/ 
1609 
1610ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); 
1611/* 
1612 Returns true (1) if file is being copied directly while reading, or false 
1613 (0) if file is a gzip stream being decompressed. 
1614 
1615 If the input file is empty, gzdirect() will return true, since the input 
1616 does not contain a gzip stream. 
1617 
1618 If gzdirect() is used immediately after gzopen() or gzdopen() it will 
1619 cause buffers to be allocated to allow reading the file to determine if it 
1620 is a gzip file. Therefore if gzbuffer() is used, it should be called before 
1621 gzdirect(). 
1622 
1623 When writing, gzdirect() returns true (1) if transparent writing was 
1624 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: 
1625 gzdirect() is not needed when writing. Transparent writing must be 
1626 explicitly requested, so the application already knows the answer. When 
1627 linking statically, using gzdirect() will include all of the zlib code for 
1628 gzip file reading and decompression, which may not be desired.) 
1629*/ 
1630 
1631ZEXTERN int ZEXPORT gzclose OF((gzFile file)); 
1632/* 
1633 Flushes all pending output if necessary, closes the compressed file and 
1634 deallocates the (de)compression state. Note that once file is closed, you 
1635 cannot call gzerror with file, since its structures have been deallocated. 
1636 gzclose must not be called more than once on the same file, just as free 
1637 must not be called more than once on the same allocation. 
1638 
1639 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a 
1640 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the 
1641 last read ended in the middle of a gzip stream, or Z_OK on success. 
1642*/ 
1643 
1644ZEXTERN int ZEXPORT gzclose_r OF((gzFile file)); 
1645ZEXTERN int ZEXPORT gzclose_w OF((gzFile file)); 
1646/* 
1647 Same as gzclose(), but gzclose_r() is only for use when reading, and 
1648 gzclose_w() is only for use when writing or appending. The advantage to 
1649 using these instead of gzclose() is that they avoid linking in zlib 
1650 compression or decompression code that is not used when only reading or only 
1651 writing respectively. If gzclose() is used, then both compression and 
1652 decompression code will be included the application when linking to a static 
1653 zlib library. 
1654*/ 
1655 
1656ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); 
1657/* 
1658 Returns the error message for the last error which occurred on the given 
1659 compressed file. errnum is set to zlib error number. If an error occurred 
1660 in the file system and not in the compression library, errnum is set to 
1661 Z_ERRNO and the application may consult errno to get the exact error code. 
1662 
1663 The application must not modify the returned string. Future calls to 
1664 this function may invalidate the previously returned string. If file is 
1665 closed, then the string previously returned by gzerror will no longer be 
1666 available. 
1667 
1668 gzerror() should be used to distinguish errors from end-of-file for those 
1669 functions above that do not distinguish those cases in their return values. 
1670*/ 
1671 
1672ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); 
1673/* 
1674 Clears the error and end-of-file flags for file. This is analogous to the 
1675 clearerr() function in stdio. This is useful for continuing to read a gzip 
1676 file that is being written concurrently. 
1677*/ 
1678 
1679#endif /* !Z_SOLO */ 
1680 
1681 /* checksum functions */ 
1682 
1683/* 
1684 These functions are not related to compression but are exported 
1685 anyway because they might be useful in applications using the compression 
1686 library. 
1687*/ 
1688 
1689ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); 
1690/* 
1691 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 
1692 return the updated checksum. If buf is Z_NULL, this function returns the 
1693 required initial value for the checksum. 
1694 
1695 An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed 
1696 much faster. 
1697 
1698 Usage example: 
1699 
1700 uLong adler = adler32(0L, Z_NULL, 0); 
1701 
1702 while (read_buffer(buffer, length) != EOF) { 
1703 adler = adler32(adler, buffer, length); 
1704 } 
1705 if (adler != original_adler) error(); 
1706*/ 
1707 
1708ZEXTERN uLong ZEXPORT adler32_z OF((uLong adler, const Bytef *buf, 
1709 z_size_t len)); 
1710/* 
1711 Same as adler32(), but with a size_t length. 
1712*/ 
1713 
1714/* 
1715ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, 
1716 z_off_t len2)); 
1717 
1718 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 
1719 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 
1720 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 
1721 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note 
1722 that the z_off_t type (like off_t) is a signed integer. If len2 is 
1723 negative, the result has no meaning or utility. 
1724*/ 
1725 
1726ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); 
1727/* 
1728 Update a running CRC-32 with the bytes buf[0..len-1] and return the 
1729 updated CRC-32. If buf is Z_NULL, this function returns the required 
1730 initial value for the crc. Pre- and post-conditioning (one's complement) is 
1731 performed within this function so it shouldn't be done by the application. 
1732 
1733 Usage example: 
1734 
1735 uLong crc = crc32(0L, Z_NULL, 0); 
1736 
1737 while (read_buffer(buffer, length) != EOF) { 
1738 crc = crc32(crc, buffer, length); 
1739 } 
1740 if (crc != original_crc) error(); 
1741*/ 
1742 
1743ZEXTERN uLong ZEXPORT crc32_z OF((uLong adler, const Bytef *buf, 
1744 z_size_t len)); 
1745/* 
1746 Same as crc32(), but with a size_t length. 
1747*/ 
1748 
1749/* 
1750ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); 
1751 
1752 Combine two CRC-32 check values into one. For two sequences of bytes, 
1753 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 
1754 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 
1755 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 
1756 len2. 
1757*/ 
1758 
1759 
1760 /* various hacks, don't look :) */ 
1761 
1762/* deflateInit and inflateInit are macros to allow checking the zlib version 
1763 * and the compiler's view of z_stream: 
1764 */ 
1765ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, 
1766 const char *version, int stream_size)); 
1767ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, 
1768 const char *version, int stream_size)); 
1769ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, 
1770 int windowBits, int memLevel, 
1771 int strategy, const char *version, 
1772 int stream_size)); 
1773ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, 
1774 const char *version, int stream_size)); 
1775ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, 
1776 unsigned char FAR *window, 
1777 const char *version, 
1778 int stream_size)); 
1779#ifdef Z_PREFIX_SET 
1780# define z_deflateInit(strm, level) \ 
1781 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 
1782# define z_inflateInit(strm) \ 
1783 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 
1784# define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 
1785 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 
1786 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 
1787# define z_inflateInit2(strm, windowBits) \ 
1788 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 
1789 (int)sizeof(z_stream)) 
1790# define z_inflateBackInit(strm, windowBits, window) \ 
1791 inflateBackInit_((strm), (windowBits), (window), \ 
1792 ZLIB_VERSION, (int)sizeof(z_stream)) 
1793#else 
1794# define deflateInit(strm, level) \ 
1795 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 
1796# define inflateInit(strm) \ 
1797 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 
1798# define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 
1799 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 
1800 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 
1801# define inflateInit2(strm, windowBits) \ 
1802 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 
1803 (int)sizeof(z_stream)) 
1804# define inflateBackInit(strm, windowBits, window) \ 
1805 inflateBackInit_((strm), (windowBits), (window), \ 
1806 ZLIB_VERSION, (int)sizeof(z_stream)) 
1807#endif 
1808 
1809#ifndef Z_SOLO 
1810 
1811/* gzgetc() macro and its supporting function and exposed data structure. Note 
1812 * that the real internal state is much larger than the exposed structure. 
1813 * This abbreviated structure exposes just enough for the gzgetc() macro. The 
1814 * user should not mess with these exposed elements, since their names or 
1815 * behavior could change in the future, perhaps even capriciously. They can 
1816 * only be used by the gzgetc() macro. You have been warned. 
1817 */ 
1818struct gzFile_s { 
1819 unsigned have; 
1820 unsigned char *next; 
1821 z_off64_t pos; 
1822}; 
1823ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */ 
1824#ifdef Z_PREFIX_SET 
1825# undef z_gzgetc 
1826# define z_gzgetc(g) \ 
1827 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g)) 
1828#else 
1829# define gzgetc(g) \ 
1830 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g)) 
1831#endif 
1832 
1833/* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or 
1834 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if 
1835 * both are true, the application gets the *64 functions, and the regular 
1836 * functions are changed to 64 bits) -- in case these are set on systems 
1837 * without large file support, _LFS64_LARGEFILE must also be true 
1838 */ 
1839#ifdef Z_LARGE64 
1840 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 
1841 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); 
1842 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); 
1843 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); 
1844 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); 
1845 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); 
1846#endif 
1847 
1848#if !defined(ZLIB_INTERNAL) && defined(Z_WANT64) 
1849# ifdef Z_PREFIX_SET 
1850# define z_gzopen z_gzopen64 
1851# define z_gzseek z_gzseek64 
1852# define z_gztell z_gztell64 
1853# define z_gzoffset z_gzoffset64 
1854# define z_adler32_combine z_adler32_combine64 
1855# define z_crc32_combine z_crc32_combine64 
1856# else 
1857# define gzopen gzopen64 
1858# define gzseek gzseek64 
1859# define gztell gztell64 
1860# define gzoffset gzoffset64 
1861# define adler32_combine adler32_combine64 
1862# define crc32_combine crc32_combine64 
1863# endif 
1864# ifndef Z_LARGE64 
1865 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 
1866 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int)); 
1867 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile)); 
1868 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile)); 
1869 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t)); 
1870 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t)); 
1871# endif 
1872#else 
1873 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); 
1874 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); 
1875 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); 
1876 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); 
1877 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 
1878 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 
1879#endif 
1880 
1881#else /* Z_SOLO */ 
1882 
1883 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 
1884 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 
1885 
1886#endif /* !Z_SOLO */ 
1887 
1888/* undocumented functions */ 
1889ZEXTERN const char * ZEXPORT zError OF((int)); 
1890ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); 
1891ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void)); 
1892ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); 
1893ZEXTERN int ZEXPORT inflateValidate OF((z_streamp, int)); 
1894ZEXTERN unsigned long ZEXPORT inflateCodesUsed OF ((z_streamp)); 
1895ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp)); 
1896ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp)); 
1897#if (defined(_WIN32) || defined(__CYGWIN__)) && !defined(Z_SOLO) 
1898ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path, 
1899 const char *mode)); 
1900#endif 
1901#if defined(STDC) || defined(Z_HAVE_STDARG_H) 
1902# ifndef Z_SOLO 
1903ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file, 
1904 const char *format, 
1905 va_list va)); 
1906# endif 
1907#endif 
1908 
1909#ifdef __cplusplus 
1910} 
1911#endif 
1912 
1913#endif /* ZLIB_H */ 
1914