2 * This file is derived from zlib.h and zconf.h from the zlib-0.95
3 * distribution by Jean-loup Gailly and Mark Adler, with some additions
4 * by Paul Mackerras to aid in implementing Deflate compression and
5 * decompression for PPP packets.
9 * ==FILEVERSION 960122==
11 * This marker is used by the Linux installation script to determine
12 * whether an up-to-date version of this file is already installed.
15 /* zlib.h -- interface of the 'zlib' general purpose compression library
16 version 0.95, Aug 16th, 1995.
18 Copyright (C) 1995 Jean-loup Gailly and Mark Adler
20 This software is provided 'as-is', without any express or implied
21 warranty. In no event will the authors be held liable for any damages
22 arising from the use of this software.
24 Permission is granted to anyone to use this software for any purpose,
25 including commercial applications, and to alter it and redistribute it
26 freely, subject to the following restrictions:
28 1. The origin of this software must not be misrepresented; you must not
29 claim that you wrote the original software. If you use this software
30 in a product, an acknowledgment in the product documentation would be
31 appreciated but is not required.
32 2. Altered source versions must be plainly marked as such, and must not be
33 misrepresented as being the original software.
34 3. This notice may not be removed or altered from any source distribution.
36 Jean-loup Gailly Mark Adler
37 gzip@prep.ai.mit.edu madler@alumni.caltech.edu
43 /* #include "zconf.h" */ /* included directly here */
45 /* zconf.h -- configuration of the zlib compression library
46 * Copyright (C) 1995 Jean-loup Gailly.
47 * For conditions of distribution and use, see copyright notice in zlib.h
50 /* From: zconf.h,v 1.12 1995/05/03 17:27:12 jloup Exp */
53 The library does not install any signal handler. It is recommended to
54 add at least a handler for SIGSEGV when decompressing; the library checks
55 the consistency of the input data whenever possible but may go nuts
56 for some forms of corrupted input.
60 * Compile with -DMAXSEG_64K if the alloc function cannot allocate more
61 * than 64k bytes at a time (needed on systems with 16-bit int).
62 * Compile with -DUNALIGNED_OK if it is OK to access shorts or ints
63 * at addresses which are not a multiple of their size.
64 * Under DOS, -DFAR=far or -DFAR=__far may be needed.
68 # if defined(MSDOS) || defined(__STDC__) || defined(__cplusplus)
73 #ifdef __MWERKS__ /* Metrowerks CodeWarrior declares fileno() in unix.h */
77 /* Maximum value for memLevel in deflateInit2 */
80 # define MAX_MEM_LEVEL 8
82 # define MAX_MEM_LEVEL 9
90 /* Maximum value for windowBits in deflateInit2 and inflateInit2 */
92 # define MAX_WBITS 15 /* 32K LZ77 window */
95 /* The memory requirements for deflate are (in bytes):
96 1 << (windowBits+2) + 1 << (memLevel+9)
97 that is: 128K for windowBits=15 + 128K for memLevel = 8 (default values)
98 plus a few kilobytes for small objects. For example, if you want to reduce
99 the default memory requirements from 256K to 128K, compile with
100 make CFLAGS="-O -DMAX_WBITS=14 -DMAX_MEM_LEVEL=7"
101 Of course this will generally degrade compression (there's no free lunch).
103 The memory requirements for inflate are (in bytes) 1 << windowBits
104 that is, 32K for windowBits=15 (default value) plus a few kilobytes
108 /* Type declarations */
110 #ifndef OF /* function prototypes */
112 # define OF(args) args
118 typedef unsigned char Byte; /* 8 bits */
119 typedef unsigned int uInt; /* 16 bits or more */
120 typedef unsigned long uLong; /* 32 bits or more */
122 typedef Byte FAR Bytef;
123 typedef char FAR charf;
124 typedef int FAR intf;
125 typedef uInt FAR uIntf;
126 typedef uLong FAR uLongf;
129 typedef void FAR *voidpf;
132 typedef Byte FAR *voidpf;
136 /* end of original zconf.h */
138 #define ZLIB_VERSION "0.95P"
141 The 'zlib' compression library provides in-memory compression and
142 decompression functions, including integrity checks of the uncompressed
143 data. This version of the library supports only one compression method
144 (deflation) but other algorithms may be added later and will have the same
147 For compression the application must provide the output buffer and
148 may optionally provide the input buffer for optimization. For decompression,
149 the application must provide the input buffer and may optionally provide
150 the output buffer for optimization.
152 Compression can be done in a single step if the buffers are large
153 enough (for example if an input file is mmap'ed), or can be done by
154 repeated calls of the compression function. In the latter case, the
155 application must provide more input and/or consume the output
156 (providing more output space) before each call.
159 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
160 typedef void (*free_func) OF((voidpf opaque, voidpf address, uInt nbytes));
162 struct internal_state;
164 typedef struct z_stream_s {
165 Bytef *next_in; /* next input byte */
166 uInt avail_in; /* number of bytes available at next_in */
167 uLong total_in; /* total nb of input bytes read so far */
169 Bytef *next_out; /* next output byte should be put there */
170 uInt avail_out; /* remaining free space at next_out */
171 uLong total_out; /* total nb of bytes output so far */
173 char *msg; /* last error message, NULL if no error */
174 struct internal_state FAR *state; /* not visible by applications */
176 alloc_func zalloc; /* used to allocate the internal state */
177 free_func zfree; /* used to free the internal state */
178 voidp opaque; /* private data object passed to zalloc and zfree */
180 Byte data_type; /* best guess about the data type: ascii or binary */
185 The application must update next_in and avail_in when avail_in has
186 dropped to zero. It must update next_out and avail_out when avail_out
187 has dropped to zero. The application must initialize zalloc, zfree and
188 opaque before calling the init function. All other fields are set by the
189 compression library and must not be updated by the application.
191 The opaque value provided by the application will be passed as the first
192 parameter for calls of zalloc and zfree. This can be useful for custom
193 memory management. The compression library attaches no meaning to the
196 zalloc must return Z_NULL if there is not enough memory for the object.
197 On 16-bit systems, the functions zalloc and zfree must be able to allocate
198 exactly 65536 bytes, but will not be required to allocate more than this
199 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
200 pointers returned by zalloc for objects of exactly 65536 bytes *must*
201 have their offset normalized to zero. The default allocation function
202 provided by this library ensures this (see zutil.c). To reduce memory
203 requirements and avoid any allocation of 64K objects, at the expense of
204 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
206 The fields total_in and total_out can be used for statistics or
207 progress reports. After compression, total_in holds the total size of
208 the uncompressed data and may be saved for use in the decompressor
209 (particularly if the decompressor wants to decompress everything in
216 #define Z_PARTIAL_FLUSH 1
217 #define Z_FULL_FLUSH 2
218 #define Z_SYNC_FLUSH 3 /* experimental: partial_flush + byte align */
220 #define Z_PACKET_FLUSH 5
221 /* See deflate() below for the usage of these constants */
224 #define Z_STREAM_END 1
226 #define Z_STREAM_ERROR (-2)
227 #define Z_DATA_ERROR (-3)
228 #define Z_MEM_ERROR (-4)
229 #define Z_BUF_ERROR (-5)
230 /* error codes for the compression/decompression functions */
232 #define Z_BEST_SPEED 1
233 #define Z_BEST_COMPRESSION 9
234 #define Z_DEFAULT_COMPRESSION (-1)
235 /* compression levels */
238 #define Z_HUFFMAN_ONLY 2
239 #define Z_DEFAULT_STRATEGY 0
244 /* Used to set the data_type field */
246 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
248 extern char *zlib_version;
249 /* The application can compare zlib_version and ZLIB_VERSION for consistency.
250 If the first character differs, the library code actually used is
251 not compatible with the zlib.h header file used by the application.
254 /* basic functions */
256 extern int inflateInit OF((z_stream *strm));
258 Initializes the internal stream state for decompression. The fields
259 zalloc and zfree must be initialized before by the caller. If zalloc and
260 zfree are set to Z_NULL, inflateInit updates them to use default allocation
263 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
264 enough memory. msg is set to null if there is no error message.
265 inflateInit does not perform any decompression: this will be done by
270 extern int inflate OF((z_stream *strm, int flush));
272 Performs one or both of the following actions:
274 - Decompress more input starting at next_in and update next_in and avail_in
275 accordingly. If not all input can be processed (because there is not
276 enough room in the output buffer), next_in is updated and processing
277 will resume at this point for the next call of inflate().
279 - Provide more output starting at next_out and update next_out and avail_out
280 accordingly. inflate() always provides as much output as possible
281 (until there is no more input data or no more space in the output buffer).
283 Before the call of inflate(), the application should ensure that at least
284 one of the actions is possible, by providing more input and/or consuming
285 more output, and updating the next_* and avail_* values accordingly.
286 The application can consume the uncompressed output when it wants, for
287 example when the output buffer is full (avail_out == 0), or after each
290 If the parameter flush is set to Z_PARTIAL_FLUSH or Z_PACKET_FLUSH,
291 inflate flushes as much output as possible to the output buffer. The
292 flushing behavior of inflate is not specified for values of the flush
293 parameter other than Z_PARTIAL_FLUSH, Z_PACKET_FLUSH or Z_FINISH, but the
294 current implementation actually flushes as much output as possible
295 anyway. For Z_PACKET_FLUSH, inflate checks that once all the input data
296 has been consumed, it is expecting to see the length field of a stored
297 block; if not, it returns Z_DATA_ERROR.
299 inflate() should normally be called until it returns Z_STREAM_END or an
300 error. However if all decompression is to be performed in a single step
301 (a single call of inflate), the parameter flush should be set to
302 Z_FINISH. In this case all pending input is processed and all pending
303 output is flushed; avail_out must be large enough to hold all the
304 uncompressed data. (The size of the uncompressed data may have been saved
305 by the compressor for this purpose.) The next operation on this stream must
306 be inflateEnd to deallocate the decompression state. The use of Z_FINISH
307 is never required, but can be used to inform inflate that a faster routine
308 may be used for the single inflate() call.
310 inflate() returns Z_OK if some progress has been made (more input
311 processed or more output produced), Z_STREAM_END if the end of the
312 compressed data has been reached and all uncompressed output has been
313 produced, Z_DATA_ERROR if the input data was corrupted, Z_STREAM_ERROR if
314 the stream structure was inconsistent (for example if next_in or next_out
315 was NULL), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR if no
316 progress is possible or if there was not enough room in the output buffer
317 when Z_FINISH is used. In the Z_DATA_ERROR case, the application may then
318 call inflateSync to look for a good compression block. */
321 extern int inflateEnd OF((z_stream *strm));
323 All dynamically allocated data structures for this stream are freed.
324 This function discards any unprocessed input and does not flush any
327 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
328 was inconsistent. In the error case, msg may be set but then points to a
329 static string (which must not be deallocated).
332 /* advanced functions */
334 extern int inflateInit2 OF((z_stream *strm,
337 This is another version of inflateInit with more compression options. The
338 fields next_out, zalloc and zfree must be initialized before by the caller.
340 The windowBits parameter is the base two logarithm of the maximum window
341 size (the size of the history buffer). It should be in the range 8..15 for
342 this version of the library (the value 16 will be allowed soon). The
343 default value is 15 if inflateInit is used instead. If a compressed stream
344 with a larger window size is given as input, inflate() will return with
345 the error code Z_DATA_ERROR instead of trying to allocate a larger window.
347 If next_out is not null, the library will use this buffer for the history
348 buffer; the buffer must either be large enough to hold the entire output
349 data, or have at least 1<<windowBits bytes. If next_out is null, the
350 library will allocate its own buffer (and leave next_out null). next_in
351 need not be provided here but must be provided by the application for the
352 next call of inflate().
354 If the history buffer is provided by the application, next_out must
355 never be changed by the application since the decompressor maintains
356 history information inside this buffer from call to call; the application
357 can only reset next_out to the beginning of the history buffer when
358 avail_out is zero and all output has been consumed.
360 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was
361 not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as
362 windowBits < 8). msg is set to null if there is no error message.
363 inflateInit2 does not perform any decompression: this will be done by
367 extern int inflateSync OF((z_stream *strm));
369 Skips invalid compressed data until the special marker (see deflate()
370 above) can be found, or until all available input is skipped. No output
373 inflateSync returns Z_OK if the special marker has been found, Z_BUF_ERROR
374 if no more input was provided, Z_DATA_ERROR if no marker has been found,
375 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
376 case, the application may save the current current value of total_in which
377 indicates where valid compressed data was found. In the error case, the
378 application may repeatedly call inflateSync, providing more input each time,
379 until success or end of the input data.
382 extern int inflateReset OF((z_stream *strm));
384 This function is equivalent to inflateEnd followed by inflateInit,
385 but does not free and reallocate all the internal decompression state.
386 The stream will keep attributes that may have been set by inflateInit2.
388 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
389 stream state was inconsistent (such as zalloc or state being NULL).
392 extern int inflateIncomp OF((z_stream *strm));
394 This function adds the data at next_in (avail_in bytes) to the output
395 history without performing any output. There must be no pending output,
396 and the decompressor must be expecting to see the start of a block.
397 Calling this function is equivalent to decompressing a stored block
398 containing the data at next_in (except that the data is not output).
401 /* checksum functions */
404 This function is not related to compression but is exported
405 anyway because it might be useful in applications using the
409 extern uLong adler32 OF((uLong adler, Bytef *buf, uInt len));
412 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
413 return the updated checksum. If buf is NULL, this function returns
414 the required initial value for the checksum.
415 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
416 much faster. Usage example:
418 uLong adler = adler32(0L, Z_NULL, 0);
420 while (read_buffer(buffer, length) != EOF) {
421 adler = adler32(adler, buffer, length);
423 if (adler != original_adler) error();
427 struct internal_state {int dummy;}; /* hack for buggy compilers */