1 /* $Id: zlib.h,v 1.1 1999/03/23 03:21:58 paulus Exp $ */
4 * This file is derived from zlib.h and zconf.h from the zlib-0.95
5 * distribution by Jean-loup Gailly and Mark Adler, with some additions
6 * by Paul Mackerras to aid in implementing Deflate compression and
7 * decompression for PPP packets.
10 /* zlib.h -- interface of the 'zlib' general purpose compression library
11 version 0.95, Aug 16th, 1995.
13 Copyright (C) 1995 Jean-loup Gailly and Mark Adler
15 This software is provided 'as-is', without any express or implied
16 warranty. In no event will the authors be held liable for any damages
17 arising from the use of this software.
19 Permission is granted to anyone to use this software for any purpose,
20 including commercial applications, and to alter it and redistribute it
21 freely, subject to the following restrictions:
23 1. The origin of this software must not be misrepresented; you must not
24 claim that you wrote the original software. If you use this software
25 in a product, an acknowledgment in the product documentation would be
26 appreciated but is not required.
27 2. Altered source versions must be plainly marked as such, and must not be
28 misrepresented as being the original software.
29 3. This notice may not be removed or altered from any source distribution.
31 Jean-loup Gailly Mark Adler
32 gzip@prep.ai.mit.edu madler@alumni.caltech.edu
38 /* #include "zconf.h" */ /* included directly here */
40 /* zconf.h -- configuration of the zlib compression library
41 * Copyright (C) 1995 Jean-loup Gailly.
42 * For conditions of distribution and use, see copyright notice in zlib.h
45 /* From: zconf.h,v 1.12 1995/05/03 17:27:12 jloup Exp */
48 The library does not install any signal handler. It is recommended to
49 add at least a handler for SIGSEGV when decompressing; the library checks
50 the consistency of the input data whenever possible but may go nuts
51 for some forms of corrupted input.
55 * Compile with -DMAXSEG_64K if the alloc function cannot allocate more
56 * than 64k bytes at a time (needed on systems with 16-bit int).
57 * Compile with -DUNALIGNED_OK if it is OK to access shorts or ints
58 * at addresses which are not a multiple of their size.
59 * Under DOS, -DFAR=far or -DFAR=__far may be needed.
63 # if defined(MSDOS) || defined(__STDC__) || defined(__cplusplus)
68 #ifdef __MWERKS__ /* Metrowerks CodeWarrior declares fileno() in unix.h */
76 /* Maximum value for windowBits in deflateInit2 and inflateInit2 */
78 # define MAX_WBITS 15 /* 32K LZ77 window */
82 The memory requirements for inflate are (in bytes) 1 << windowBits
83 that is, 32K for windowBits=15 (default value) plus a few kilobytes
87 /* Type declarations */
89 #ifndef OF /* function prototypes */
91 # define OF(args) args
97 typedef unsigned char Byte; /* 8 bits */
98 typedef unsigned int uInt; /* 16 bits or more */
99 typedef unsigned long uLong; /* 32 bits or more */
101 typedef Byte FAR Bytef;
102 typedef char FAR charf;
103 typedef int FAR intf;
104 typedef uInt FAR uIntf;
105 typedef uLong FAR uLongf;
108 typedef void FAR *voidpf;
111 typedef Byte FAR *voidpf;
115 /* end of original zconf.h */
117 #define ZLIB_VERSION "0.95P"
120 The 'zlib' compression library provides in-memory compression and
121 decompression functions, including integrity checks of the uncompressed
122 data. This version of the library supports only one compression method
123 (deflation) but other algorithms may be added later and will have the same
126 For compression the application must provide the output buffer and
127 may optionally provide the input buffer for optimization. For decompression,
128 the application must provide the input buffer and may optionally provide
129 the output buffer for optimization.
131 Compression can be done in a single step if the buffers are large
132 enough (for example if an input file is mmap'ed), or can be done by
133 repeated calls of the compression function. In the latter case, the
134 application must provide more input and/or consume the output
135 (providing more output space) before each call.
138 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
139 typedef void (*free_func) OF((voidpf opaque, voidpf address, uInt nbytes));
141 struct internal_state;
143 typedef struct z_stream_s {
144 Bytef *next_in; /* next input byte */
145 uInt avail_in; /* number of bytes available at next_in */
146 uLong total_in; /* total nb of input bytes read so far */
148 Bytef *next_out; /* next output byte should be put there */
149 uInt avail_out; /* remaining free space at next_out */
150 uLong total_out; /* total nb of bytes output so far */
152 char *msg; /* last error message, NULL if no error */
153 struct internal_state FAR *state; /* not visible by applications */
155 alloc_func zalloc; /* used to allocate the internal state */
156 free_func zfree; /* used to free the internal state */
157 voidp opaque; /* private data object passed to zalloc and zfree */
159 Byte data_type; /* best guess about the data type: ascii or binary */
164 The application must update next_in and avail_in when avail_in has
165 dropped to zero. It must update next_out and avail_out when avail_out
166 has dropped to zero. The application must initialize zalloc, zfree and
167 opaque before calling the init function. All other fields are set by the
168 compression library and must not be updated by the application.
170 The opaque value provided by the application will be passed as the first
171 parameter for calls of zalloc and zfree. This can be useful for custom
172 memory management. The compression library attaches no meaning to the
175 zalloc must return Z_NULL if there is not enough memory for the object.
176 On 16-bit systems, the functions zalloc and zfree must be able to allocate
177 exactly 65536 bytes, but will not be required to allocate more than this
178 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
179 pointers returned by zalloc for objects of exactly 65536 bytes *must*
180 have their offset normalized to zero. The default allocation function
181 provided by this library ensures this (see zutil.c). To reduce memory
182 requirements and avoid any allocation of 64K objects, at the expense of
183 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
185 The fields total_in and total_out can be used for statistics or
186 progress reports. After compression, total_in holds the total size of
187 the uncompressed data and may be saved for use in the decompressor
188 (particularly if the decompressor wants to decompress everything in
195 #define Z_PARTIAL_FLUSH 1
196 #define Z_FULL_FLUSH 2
197 #define Z_SYNC_FLUSH 3 /* experimental: partial_flush + byte align */
199 #define Z_PACKET_FLUSH 5
200 /* See deflate() below for the usage of these constants */
203 #define Z_STREAM_END 1
205 #define Z_STREAM_ERROR (-2)
206 #define Z_DATA_ERROR (-3)
207 #define Z_MEM_ERROR (-4)
208 #define Z_BUF_ERROR (-5)
209 /* error codes for the compression/decompression functions */
211 #define Z_BEST_SPEED 1
212 #define Z_BEST_COMPRESSION 9
213 #define Z_DEFAULT_COMPRESSION (-1)
214 /* compression levels */
217 #define Z_HUFFMAN_ONLY 2
218 #define Z_DEFAULT_STRATEGY 0
223 /* Used to set the data_type field */
225 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
227 extern char *zlib_version;
228 /* The application can compare zlib_version and ZLIB_VERSION for consistency.
229 If the first character differs, the library code actually used is
230 not compatible with the zlib.h header file used by the application.
233 /* basic functions */
235 extern int inflateInit OF((z_stream *strm));
237 Initializes the internal stream state for decompression. The fields
238 zalloc and zfree must be initialized before by the caller. If zalloc and
239 zfree are set to Z_NULL, inflateInit updates them to use default allocation
242 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
243 enough memory. msg is set to null if there is no error message.
244 inflateInit does not perform any decompression: this will be done by
249 extern int inflate OF((z_stream *strm, int flush));
251 Performs one or both of the following actions:
253 - Decompress more input starting at next_in and update next_in and avail_in
254 accordingly. If not all input can be processed (because there is not
255 enough room in the output buffer), next_in is updated and processing
256 will resume at this point for the next call of inflate().
258 - Provide more output starting at next_out and update next_out and avail_out
259 accordingly. inflate() always provides as much output as possible
260 (until there is no more input data or no more space in the output buffer).
262 Before the call of inflate(), the application should ensure that at least
263 one of the actions is possible, by providing more input and/or consuming
264 more output, and updating the next_* and avail_* values accordingly.
265 The application can consume the uncompressed output when it wants, for
266 example when the output buffer is full (avail_out == 0), or after each
269 If the parameter flush is set to Z_PARTIAL_FLUSH or Z_PACKET_FLUSH,
270 inflate flushes as much output as possible to the output buffer. The
271 flushing behavior of inflate is not specified for values of the flush
272 parameter other than Z_PARTIAL_FLUSH, Z_PACKET_FLUSH or Z_FINISH, but the
273 current implementation actually flushes as much output as possible
274 anyway. For Z_PACKET_FLUSH, inflate checks that once all the input data
275 has been consumed, it is expecting to see the length field of a stored
276 block; if not, it returns Z_DATA_ERROR.
278 inflate() should normally be called until it returns Z_STREAM_END or an
279 error. However if all decompression is to be performed in a single step
280 (a single call of inflate), the parameter flush should be set to
281 Z_FINISH. In this case all pending input is processed and all pending
282 output is flushed; avail_out must be large enough to hold all the
283 uncompressed data. (The size of the uncompressed data may have been saved
284 by the compressor for this purpose.) The next operation on this stream must
285 be inflateEnd to deallocate the decompression state. The use of Z_FINISH
286 is never required, but can be used to inform inflate that a faster routine
287 may be used for the single inflate() call.
289 inflate() returns Z_OK if some progress has been made (more input
290 processed or more output produced), Z_STREAM_END if the end of the
291 compressed data has been reached and all uncompressed output has been
292 produced, Z_DATA_ERROR if the input data was corrupted, Z_STREAM_ERROR if
293 the stream structure was inconsistent (for example if next_in or next_out
294 was NULL), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR if no
295 progress is possible or if there was not enough room in the output buffer
296 when Z_FINISH is used. In the Z_DATA_ERROR case, the application may then
297 call inflateSync to look for a good compression block. */
300 extern int inflateEnd OF((z_stream *strm));
302 All dynamically allocated data structures for this stream are freed.
303 This function discards any unprocessed input and does not flush any
306 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
307 was inconsistent. In the error case, msg may be set but then points to a
308 static string (which must not be deallocated).
311 /* advanced functions */
314 The following functions are needed only in some special applications.
317 extern int inflateInit2 OF((z_stream *strm,
320 This is another version of inflateInit with more compression options. The
321 fields next_out, zalloc and zfree must be initialized before by the caller.
323 The windowBits parameter is the base two logarithm of the maximum window
324 size (the size of the history buffer). It should be in the range 8..15 for
325 this version of the library (the value 16 will be allowed soon). The
326 default value is 15 if inflateInit is used instead. If a compressed stream
327 with a larger window size is given as input, inflate() will return with
328 the error code Z_DATA_ERROR instead of trying to allocate a larger window.
330 If next_out is not null, the library will use this buffer for the history
331 buffer; the buffer must either be large enough to hold the entire output
332 data, or have at least 1<<windowBits bytes. If next_out is null, the
333 library will allocate its own buffer (and leave next_out null). next_in
334 need not be provided here but must be provided by the application for the
335 next call of inflate().
337 If the history buffer is provided by the application, next_out must
338 never be changed by the application since the decompressor maintains
339 history information inside this buffer from call to call; the application
340 can only reset next_out to the beginning of the history buffer when
341 avail_out is zero and all output has been consumed.
343 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was
344 not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as
345 windowBits < 8). msg is set to null if there is no error message.
346 inflateInit2 does not perform any decompression: this will be done by
350 extern int inflateSync OF((z_stream *strm));
352 Skips invalid compressed data until the special marker (see deflate()
353 above) can be found, or until all available input is skipped. No output
356 inflateSync returns Z_OK if the special marker has been found, Z_BUF_ERROR
357 if no more input was provided, Z_DATA_ERROR if no marker has been found,
358 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
359 case, the application may save the current current value of total_in which
360 indicates where valid compressed data was found. In the error case, the
361 application may repeatedly call inflateSync, providing more input each time,
362 until success or end of the input data.
365 extern int inflateReset OF((z_stream *strm));
367 This function is equivalent to inflateEnd followed by inflateInit,
368 but does not free and reallocate all the internal decompression state.
369 The stream will keep attributes that may have been set by inflateInit2.
371 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
372 stream state was inconsistent (such as zalloc or state being NULL).
375 extern int inflateIncomp OF((z_stream *strm));
377 This function adds the data at next_in (avail_in bytes) to the output
378 history without performing any output. There must be no pending output,
379 and the decompressor must be expecting to see the start of a block.
380 Calling this function is equivalent to decompressing a stored block
381 containing the data at next_in (except that the data is not output).
384 /* checksum functions */
387 This function is not related to compression but is exported
388 anyway because it might be useful in applications using the
392 extern uLong adler32 OF((uLong adler, Bytef *buf, uInt len));
395 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
396 return the updated checksum. If buf is NULL, this function returns
397 the required initial value for the checksum.
398 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
399 much faster. Usage example:
401 uLong adler = adler32(0L, Z_NULL, 0);
403 while (read_buffer(buffer, length) != EOF) {
404 adler = adler32(adler, buffer, length);
406 if (adler != original_adler) error();
410 struct internal_state {int dummy;}; /* hack for buggy compilers */