| /* zlib.h -- interface of the 'zlib' general purpose compression library |
| version 1.1.4, March 11th, 2002 |
| |
| Copyright (C) 1995-2002 Jean-loup Gailly and Mark Adler |
| |
| This software is provided 'as-is', without any express or implied |
| warranty. In no event will the authors be held liable for any damages |
| arising from the use of this software. |
| |
| Permission is granted to anyone to use this software for any purpose, |
| including commercial applications, and to alter it and redistribute it |
| freely, subject to the following restrictions: |
| |
| 1. The origin of this software must not be misrepresented; you must not |
| claim that you wrote the original software. If you use this software |
| in a product, an acknowledgment in the product documentation would be |
| appreciated but is not required. |
| 2. Altered source versions must be plainly marked as such, and must not be |
| misrepresented as being the original software. |
| 3. This notice may not be removed or altered from any source distribution. |
| |
| Jean-loup Gailly Mark Adler |
| jloup@gzip.org madler@alumni.caltech.edu |
| |
| |
| The data format used by the zlib library is described by RFCs (Request for |
| Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt |
| (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format). |
| */ |
| |
| #ifndef _ZLIB_H |
| #define _ZLIB_H |
| |
| #include "ftzconf.h" |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| #define ZLIB_VERSION "1.1.4" |
| |
| /* |
| The 'zlib' compression library provides in-memory compression and |
| decompression functions, including integrity checks of the uncompressed |
| data. This version of the library supports only one compression method |
| (deflation) but other algorithms will be added later and will have the same |
| stream interface. |
| |
| Compression can be done in a single step if the buffers are large |
| enough (for example if an input file is mmap'ed), or can be done by |
| repeated calls of the compression function. In the latter case, the |
| application must provide more input and/or consume the output |
| (providing more output space) before each call. |
| |
| The library also supports reading and writing files in gzip (.gz) format |
| with an interface similar to that of stdio. |
| |
| The library does not install any signal handler. The decoder checks |
| the consistency of the compressed data, so the library should never |
| crash even in case of corrupted input. |
| */ |
| |
| typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); |
| typedef void (*free_func) OF((voidpf opaque, voidpf address)); |
| |
| struct internal_state; |
| |
| typedef struct z_stream_s { |
| Bytef *next_in; /* next input byte */ |
| uInt avail_in; /* number of bytes available at next_in */ |
| uLong total_in; /* total nb of input bytes read so far */ |
| |
| Bytef *next_out; /* next output byte should be put there */ |
| uInt avail_out; /* remaining free space at next_out */ |
| uLong total_out; /* total nb of bytes output so far */ |
| |
| char *msg; /* last error message, NULL if no error */ |
| struct internal_state FAR *state; /* not visible by applications */ |
| |
| alloc_func zalloc; /* used to allocate the internal state */ |
| free_func zfree; /* used to free the internal state */ |
| voidpf opaque; /* private data object passed to zalloc and zfree */ |
| |
| int data_type; /* best guess about the data type: ascii or binary */ |
| uLong adler; /* adler32 value of the uncompressed data */ |
| uLong reserved; /* reserved for future use */ |
| } z_stream; |
| |
| typedef z_stream FAR *z_streamp; |
| |
| /* |
| The application must update next_in and avail_in when avail_in has |
| dropped to zero. It must update next_out and avail_out when avail_out |
| has dropped to zero. The application must initialize zalloc, zfree and |
| opaque before calling the init function. All other fields are set by the |
| compression library and must not be updated by the application. |
| |
| The opaque value provided by the application will be passed as the first |
| parameter for calls of zalloc and zfree. This can be useful for custom |
| memory management. The compression library attaches no meaning to the |
| opaque value. |
| |
| zalloc must return Z_NULL if there is not enough memory for the object. |
| If zlib is used in a multi-threaded application, zalloc and zfree must be |
| thread safe. |
| |
| On 16-bit systems, the functions zalloc and zfree must be able to allocate |
| exactly 65536 bytes, but will not be required to allocate more than this |
| if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, |
| pointers returned by zalloc for objects of exactly 65536 bytes *must* |
| have their offset normalized to zero. The default allocation function |
| provided by this library ensures this (see zutil.c). To reduce memory |
| requirements and avoid any allocation of 64K objects, at the expense of |
| compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). |
| |
| The fields total_in and total_out can be used for statistics or |
| progress reports. After compression, total_in holds the total size of |
| the uncompressed data and may be saved for use in the decompressor |
| (particularly if the decompressor wants to decompress everything in |
| a single step). |
| */ |
| |
| /* constants */ |
| |
| #define Z_NO_FLUSH 0 |
| #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ |
| #define Z_SYNC_FLUSH 2 |
| #define Z_FULL_FLUSH 3 |
| #define Z_FINISH 4 |
| /* Allowed flush values; see deflate() below for details */ |
| |
| #define Z_OK 0 |
| #define Z_STREAM_END 1 |
| #define Z_NEED_DICT 2 |
| #define Z_ERRNO (-1) |
| #define Z_STREAM_ERROR (-2) |
| #define Z_DATA_ERROR (-3) |
| #define Z_MEM_ERROR (-4) |
| #define Z_BUF_ERROR (-5) |
| #define Z_VERSION_ERROR (-6) |
| /* Return codes for the compression/decompression functions. Negative |
| * values are errors, positive values are used for special but normal events. |
| */ |
| |
| #define Z_NO_COMPRESSION 0 |
| #define Z_BEST_SPEED 1 |
| #define Z_BEST_COMPRESSION 9 |
| #define Z_DEFAULT_COMPRESSION (-1) |
| /* compression levels */ |
| |
| #define Z_FILTERED 1 |
| #define Z_HUFFMAN_ONLY 2 |
| #define Z_DEFAULT_STRATEGY 0 |
| /* compression strategy; see deflateInit2() below for details */ |
| |
| #define Z_BINARY 0 |
| #define Z_ASCII 1 |
| #define Z_UNKNOWN 2 |
| /* Possible values of the data_type field */ |
| |
| #define Z_DEFLATED 8 |
| /* The deflate compression method (the only one supported in this version) */ |
| |
| #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ |
| |
| |
| /* basic functions */ |
| |
| /* The application can compare zlibVersion and ZLIB_VERSION for consistency. |
| If the first character differs, the library code actually used is |
| not compatible with the zlib.h header file used by the application. |
| This check is automatically made by deflateInit and inflateInit. |
| */ |
| |
| /* |
| ZEXTERN(int) deflateInit OF((z_streamp strm, int level)); |
| |
| Initializes the internal stream state for compression. The fields |
| zalloc, zfree and opaque must be initialized before by the caller. |
| If zalloc and zfree are set to Z_NULL, deflateInit updates them to |
| use default allocation functions. |
| |
| The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: |
| 1 gives best speed, 9 gives best compression, 0 gives no compression at |
| all (the input data is simply copied a block at a time). |
| Z_DEFAULT_COMPRESSION requests a default compromise between speed and |
| compression (currently equivalent to level 6). |
| |
| deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not |
| enough memory, Z_STREAM_ERROR if level is not a valid compression level, |
| Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible |
| with the version assumed by the caller (ZLIB_VERSION). |
| msg is set to null if there is no error message. deflateInit does not |
| perform any compression: this will be done by deflate(). |
| */ |
| |
| |
| /* |
| deflate compresses as much data as possible, and stops when the input |
| buffer becomes empty or the output buffer becomes full. It may introduce some |
| output latency (reading input without producing any output) except when |
| forced to flush. |
| |
| The detailed semantics are as follows. deflate performs one or both of the |
| following actions: |
| |
| - Compress more input starting at next_in and update next_in and avail_in |
| accordingly. If not all input can be processed (because there is not |
| enough room in the output buffer), next_in and avail_in are updated and |
| processing will resume at this point for the next call of deflate(). |
| |
| - Provide more output starting at next_out and update next_out and avail_out |
| accordingly. This action is forced if the parameter flush is non zero. |
| Forcing flush frequently degrades the compression ratio, so this parameter |
| should be set only when necessary (in interactive applications). |
| Some output may be provided even if flush is not set. |
| |
| Before the call of deflate(), the application should ensure that at least |
| one of the actions is possible, by providing more input and/or consuming |
| more output, and updating avail_in or avail_out accordingly; avail_out |
| should never be zero before the call. The application can consume the |
| compressed output when it wants, for example when the output buffer is full |
| (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK |
| and with zero avail_out, it must be called again after making room in the |
| output buffer because there might be more output pending. |
| |
| If the parameter flush is set to Z_SYNC_FLUSH, all pending output is |
| flushed to the output buffer and the output is aligned on a byte boundary, so |
| that the decompressor can get all input data available so far. (In particular |
| avail_in is zero after the call if enough output space has been provided |
| before the call.) Flushing may degrade compression for some compression |
| algorithms and so it should be used only when necessary. |
| |
| If flush is set to Z_FULL_FLUSH, all output is flushed as with |
| Z_SYNC_FLUSH, and the compression state is reset so that decompression can |
| restart from this point if previous compressed data has been damaged or if |
| random access is desired. Using Z_FULL_FLUSH too often can seriously degrade |
| the compression. |
| |
| If deflate returns with avail_out == 0, this function must be called again |
| with the same value of the flush parameter and more output space (updated |
| avail_out), until the flush is complete (deflate returns with non-zero |
| avail_out). |
| |
| If the parameter flush is set to Z_FINISH, pending input is processed, |
| pending output is flushed and deflate returns with Z_STREAM_END if there |
| was enough output space; if deflate returns with Z_OK, this function must be |
| called again with Z_FINISH and more output space (updated avail_out) but no |
| more input data, until it returns with Z_STREAM_END or an error. After |
| deflate has returned Z_STREAM_END, the only possible operations on the |
| stream are deflateReset or deflateEnd. |
| |
| Z_FINISH can be used immediately after deflateInit if all the compression |
| is to be done in a single step. In this case, avail_out must be at least |
| 0.1% larger than avail_in plus 12 bytes. If deflate does not return |
| Z_STREAM_END, then it must be called again as described above. |
| |
| deflate() sets strm->adler to the adler32 checksum of all input read |
| so far (that is, total_in bytes). |
| |
| deflate() may update data_type if it can make a good guess about |
| the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered |
| binary. This field is only for information purposes and does not affect |
| the compression algorithm in any manner. |
| |
| deflate() returns Z_OK if some progress has been made (more input |
| processed or more output produced), Z_STREAM_END if all input has been |
| consumed and all output has been produced (only when flush is set to |
| Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example |
| if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible |
| (for example avail_in or avail_out was zero). |
| */ |
| |
| |
| /* |
| All dynamically allocated data structures for this stream are freed. |
| This function discards any unprocessed input and does not flush any |
| pending output. |
| |
| deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the |
| stream state was inconsistent, Z_DATA_ERROR if the stream was freed |
| prematurely (some input or output was discarded). In the error case, |
| msg may be set but then points to a static string (which must not be |
| deallocated). |
| */ |
| |
| |
| /* |
| ZEXTERN(int) inflateInit OF((z_streamp strm)); |
| |
| Initializes the internal stream state for decompression. The fields |
| next_in, avail_in, zalloc, zfree and opaque must be initialized before by |
| the caller. If next_in is not Z_NULL and avail_in is large enough (the exact |
| value depends on the compression method), inflateInit determines the |
| compression method from the zlib header and allocates all data structures |
| accordingly; otherwise the allocation will be deferred to the first call of |
| inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to |
| use default allocation functions. |
| |
| inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| memory, Z_VERSION_ERROR if the zlib library version is incompatible with the |
| version assumed by the caller. msg is set to null if there is no error |
| message. inflateInit does not perform any decompression apart from reading |
| the zlib header if present: this will be done by inflate(). (So next_in and |
| avail_in may be modified, but next_out and avail_out are unchanged.) |
| */ |
| |
| |
| ZEXTERN(int) inflate OF((z_streamp strm, int flush)); |
| /* |
| inflate decompresses as much data as possible, and stops when the input |
| buffer becomes empty or the output buffer becomes full. It may some |
| introduce some output latency (reading input without producing any output) |
| except when forced to flush. |
| |
| The detailed semantics are as follows. inflate performs one or both of the |
| following actions: |
| |
| - Decompress more input starting at next_in and update next_in and avail_in |
| accordingly. If not all input can be processed (because there is not |
| enough room in the output buffer), next_in is updated and processing |
| will resume at this point for the next call of inflate(). |
| |
| - Provide more output starting at next_out and update next_out and avail_out |
| accordingly. inflate() provides as much output as possible, until there |
| is no more input data or no more space in the output buffer (see below |
| about the flush parameter). |
| |
| Before the call of inflate(), the application should ensure that at least |
| one of the actions is possible, by providing more input and/or consuming |
| more output, and updating the next_* and avail_* values accordingly. |
| The application can consume the uncompressed output when it wants, for |
| example when the output buffer is full (avail_out == 0), or after each |
| call of inflate(). If inflate returns Z_OK and with zero avail_out, it |
| must be called again after making room in the output buffer because there |
| might be more output pending. |
| |
| If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much |
| output as possible to the output buffer. The flushing behavior of inflate is |
| not specified for values of the flush parameter other than Z_SYNC_FLUSH |
| and Z_FINISH, but the current implementation actually flushes as much output |
| as possible anyway. |
| |
| inflate() should normally be called until it returns Z_STREAM_END or an |
| error. However if all decompression is to be performed in a single step |
| (a single call of inflate), the parameter flush should be set to |
| Z_FINISH. In this case all pending input is processed and all pending |
| output is flushed; avail_out must be large enough to hold all the |
| uncompressed data. (The size of the uncompressed data may have been saved |
| by the compressor for this purpose.) The next operation on this stream must |
| be inflateEnd to deallocate the decompression state. The use of Z_FINISH |
| is never required, but can be used to inform inflate that a faster routine |
| may be used for the single inflate() call. |
| |
| If a preset dictionary is needed at this point (see inflateSetDictionary |
| below), inflate sets strm-adler to the adler32 checksum of the |
| dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise |
| it sets strm->adler to the adler32 checksum of all output produced |
| so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or |
| an error code as described below. At the end of the stream, inflate() |
| checks that its computed adler32 checksum is equal to that saved by the |
| compressor and returns Z_STREAM_END only if the checksum is correct. |
| |
| inflate() returns Z_OK if some progress has been made (more input processed |
| or more output produced), Z_STREAM_END if the end of the compressed data has |
| been reached and all uncompressed output has been produced, Z_NEED_DICT if a |
| preset dictionary is needed at this point, Z_DATA_ERROR if the input data was |
| corrupted (input stream not conforming to the zlib format or incorrect |
| adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent |
| (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not |
| enough memory, Z_BUF_ERROR if no progress is possible or if there was not |
| enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR |
| case, the application may then call inflateSync to look for a good |
| compression block. |
| */ |
| |
| |
| ZEXTERN(int) inflateEnd OF((z_streamp strm)); |
| /* |
| All dynamically allocated data structures for this stream are freed. |
| This function discards any unprocessed input and does not flush any |
| pending output. |
| |
| inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state |
| was inconsistent. In the error case, msg may be set but then points to a |
| static string (which must not be deallocated). |
| */ |
| |
| /* Advanced functions */ |
| |
| /* |
| The following functions are needed only in some special applications. |
| */ |
| |
| /* |
| ZEXTERN(int) deflateInit2 OF((z_streamp strm, |
| int level, |
| int method, |
| int windowBits, |
| int memLevel, |
| int strategy)); |
| |
| This is another version of deflateInit with more compression options. The |
| fields next_in, zalloc, zfree and opaque must be initialized before by |
| the caller. |
| |
| The method parameter is the compression method. It must be Z_DEFLATED in |
| this version of the library. |
| |
| The windowBits parameter is the base two logarithm of the window size |
| (the size of the history buffer). It should be in the range 8..15 for this |
| version of the library. Larger values of this parameter result in better |
| compression at the expense of memory usage. The default value is 15 if |
| deflateInit is used instead. |
| |
| The memLevel parameter specifies how much memory should be allocated |
| for the internal compression state. memLevel=1 uses minimum memory but |
| is slow and reduces compression ratio; memLevel=9 uses maximum memory |
| for optimal speed. The default value is 8. See zconf.h for total memory |
| usage as a function of windowBits and memLevel. |
| |
| The strategy parameter is used to tune the compression algorithm. Use the |
| value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a |
| filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no |
| string match). Filtered data consists mostly of small values with a |
| somewhat random distribution. In this case, the compression algorithm is |
| tuned to compress them better. The effect of Z_FILTERED is to force more |
| Huffman coding and less string matching; it is somewhat intermediate |
| between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects |
| the compression ratio but not the correctness of the compressed output even |
| if it is not set appropriately. |
| |
| deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid |
| method). msg is set to null if there is no error message. deflateInit2 does |
| not perform any compression: this will be done by deflate(). |
| */ |
| |
| /* |
| Initializes the compression dictionary from the given byte sequence |
| without producing any compressed output. This function must be called |
| immediately after deflateInit, deflateInit2 or deflateReset, before any |
| call of deflate. The compressor and decompressor must use exactly the same |
| dictionary (see inflateSetDictionary). |
| |
| The dictionary should consist of strings (byte sequences) that are likely |
| to be encountered later in the data to be compressed, with the most commonly |
| used strings preferably put towards the end of the dictionary. Using a |
| dictionary is most useful when the data to be compressed is short and can be |
| predicted with good accuracy; the data can then be compressed better than |
| with the default empty dictionary. |
| |
| Depending on the size of the compression data structures selected by |
| deflateInit or deflateInit2, a part of the dictionary may in effect be |
| discarded, for example if the dictionary is larger than the window size in |
| deflate or deflate2. Thus the strings most likely to be useful should be |
| put at the end of the dictionary, not at the front. |
| |
| Upon return of this function, strm->adler is set to the Adler32 value |
| of the dictionary; the decompressor may later use this value to determine |
| which dictionary has been used by the compressor. (The Adler32 value |
| applies to the whole dictionary even if only a subset of the dictionary is |
| actually used by the compressor.) |
| |
| deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a |
| parameter is invalid (such as NULL dictionary) or the stream state is |
| inconsistent (for example if deflate has already been called for this stream |
| or if the compression method is bsort). deflateSetDictionary does not |
| perform any compression: this will be done by deflate(). |
| */ |
| |
| /* |
| Sets the destination stream as a complete copy of the source stream. |
| |
| This function can be useful when several compression strategies will be |
| tried, for example when there are several ways of pre-processing the input |
| data with a filter. The streams that will be discarded should then be freed |
| by calling deflateEnd. Note that deflateCopy duplicates the internal |
| compression state which can be quite large, so this strategy is slow and |
| can consume lots of memory. |
| |
| deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
| enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
| (such as zalloc being NULL). msg is left unchanged in both source and |
| destination. |
| */ |
| |
| /* |
| This function is equivalent to deflateEnd followed by deflateInit, |
| but does not free and reallocate all the internal compression state. |
| The stream will keep the same compression level and any other attributes |
| that may have been set by deflateInit2. |
| |
| deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
| stream state was inconsistent (such as zalloc or state being NULL). |
| */ |
| |
| /* |
| Dynamically update the compression level and compression strategy. The |
| interpretation of level and strategy is as in deflateInit2. This can be |
| used to switch between compression and straight copy of the input data, or |
| to switch to a different kind of input data requiring a different |
| strategy. If the compression level is changed, the input available so far |
| is compressed with the old level (and may be flushed); the new level will |
| take effect only at the next call of deflate(). |
| |
| Before the call of deflateParams, the stream state must be set as for |
| a call of deflate(), since the currently available input may have to |
| be compressed and flushed. In particular, strm->avail_out must be non-zero. |
| |
| deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source |
| stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR |
| if strm->avail_out was zero. |
| */ |
| |
| /* |
| ZEXTERN(int) inflateInit2 OF((z_streamp strm, |
| int windowBits)); |
| |
| This is another version of inflateInit with an extra parameter. The |
| fields next_in, avail_in, zalloc, zfree and opaque must be initialized |
| before by the caller. |
| |
| The windowBits parameter is the base two logarithm of the maximum window |
| size (the size of the history buffer). It should be in the range 8..15 for |
| this version of the library. The default value is 15 if inflateInit is used |
| instead. If a compressed stream with a larger window size is given as |
| input, inflate() will return with the error code Z_DATA_ERROR instead of |
| trying to allocate a larger window. |
| |
| inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative |
| memLevel). msg is set to null if there is no error message. inflateInit2 |
| does not perform any decompression apart from reading the zlib header if |
| present: this will be done by inflate(). (So next_in and avail_in may be |
| modified, but next_out and avail_out are unchanged.) |
| */ |
| |
| /* |
| Initializes the decompression dictionary from the given uncompressed byte |
| sequence. This function must be called immediately after a call of inflate |
| if this call returned Z_NEED_DICT. The dictionary chosen by the compressor |
| can be determined from the Adler32 value returned by this call of |
| inflate. The compressor and decompressor must use exactly the same |
| dictionary (see deflateSetDictionary). |
| |
| inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a |
| parameter is invalid (such as NULL dictionary) or the stream state is |
| inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the |
| expected one (incorrect Adler32 value). inflateSetDictionary does not |
| perform any decompression: this will be done by subsequent calls of |
| inflate(). |
| */ |
| |
| /* |
| Skips invalid compressed data until a full flush point (see above the |
| description of deflate with Z_FULL_FLUSH) can be found, or until all |
| available input is skipped. No output is provided. |
| |
| inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR |
| if no more input was provided, Z_DATA_ERROR if no flush point has been found, |
| or Z_STREAM_ERROR if the stream structure was inconsistent. In the success |
| case, the application may save the current value of total_in which |
| indicates where valid compressed data was found. In the error case, the |
| application may repeatedly call inflateSync, providing more input each time, |
| until success or end of the input data. |
| */ |
| |
| ZEXTERN(int) inflateReset OF((z_streamp strm)); |
| /* |
| This function is equivalent to inflateEnd followed by inflateInit, |
| but does not free and reallocate all the internal decompression state. |
| The stream will keep attributes that may have been set by inflateInit2. |
| |
| inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
| stream state was inconsistent (such as zalloc or state being NULL). |
| */ |
| |
| |
| /* utility functions */ |
| |
| /* |
| The following utility functions are implemented on top of the |
| basic stream-oriented functions. To simplify the interface, some |
| default options are assumed (compression level and memory usage, |
| standard memory allocation functions). The source code of these |
| utility functions can easily be modified if you need special options. |
| */ |
| |
| /* |
| Compresses the source buffer into the destination buffer. sourceLen is |
| the byte length of the source buffer. Upon entry, destLen is the total |
| size of the destination buffer, which must be at least 0.1% larger than |
| sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the |
| compressed buffer. |
| This function can be used to compress a whole file at once if the |
| input file is mmap'ed. |
| compress returns Z_OK if success, Z_MEM_ERROR if there was not |
| enough memory, Z_BUF_ERROR if there was not enough room in the output |
| buffer. |
| */ |
| |
| /* |
| Compresses the source buffer into the destination buffer. The level |
| parameter has the same meaning as in deflateInit. sourceLen is the byte |
| length of the source buffer. Upon entry, destLen is the total size of the |
| destination buffer, which must be at least 0.1% larger than sourceLen plus |
| 12 bytes. Upon exit, destLen is the actual size of the compressed buffer. |
| |
| compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| memory, Z_BUF_ERROR if there was not enough room in the output buffer, |
| Z_STREAM_ERROR if the level parameter is invalid. |
| */ |
| |
| /* |
| Decompresses the source buffer into the destination buffer. sourceLen is |
| the byte length of the source buffer. Upon entry, destLen is the total |
| size of the destination buffer, which must be large enough to hold the |
| entire uncompressed data. (The size of the uncompressed data must have |
| been saved previously by the compressor and transmitted to the decompressor |
| by some mechanism outside the scope of this compression library.) |
| Upon exit, destLen is the actual size of the compressed buffer. |
| This function can be used to decompress a whole file at once if the |
| input file is mmap'ed. |
| |
| uncompress returns Z_OK if success, Z_MEM_ERROR if there was not |
| enough memory, Z_BUF_ERROR if there was not enough room in the output |
| buffer, or Z_DATA_ERROR if the input data was corrupted. |
| */ |
| |
| |
| /* |
| Opens a gzip (.gz) file for reading or writing. The mode parameter |
| is as in fopen ("rb" or "wb") but can also include a compression level |
| ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for |
| Huffman only compression as in "wb1h". (See the description |
| of deflateInit2 for more information about the strategy parameter.) |
| |
| gzopen can be used to read a file which is not in gzip format; in this |
| case gzread will directly read from the file without decompression. |
| |
| gzopen returns NULL if the file could not be opened or if there was |
| insufficient memory to allocate the (de)compression state; errno |
| can be checked to distinguish the two cases (if errno is zero, the |
| zlib error is Z_MEM_ERROR). */ |
| |
| /* |
| gzdopen() associates a gzFile with the file descriptor fd. File |
| descriptors are obtained from calls like open, dup, creat, pipe or |
| fileno (in the file has been previously opened with fopen). |
| The mode parameter is as in gzopen. |
| The next call of gzclose on the returned gzFile will also close the |
| file descriptor fd, just like fclose(fdopen(fd), mode) closes the file |
| descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). |
| gzdopen returns NULL if there was insufficient memory to allocate |
| the (de)compression state. |
| */ |
| |
| /* |
| Dynamically update the compression level or strategy. See the description |
| of deflateInit2 for the meaning of these parameters. |
| gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not |
| opened for writing. |
| */ |
| |
| /* |
| Reads the given number of uncompressed bytes from the compressed file. |
| If the input file was not in gzip format, gzread copies the given number |
| of bytes into the buffer. |
| gzread returns the number of uncompressed bytes actually read (0 for |
| end of file, -1 for error). */ |
| |
| /* |
| Writes the given number of uncompressed bytes into the compressed file. |
| gzwrite returns the number of uncompressed bytes actually written |
| (0 in case of error). |
| */ |
| |
| /* |
| Converts, formats, and writes the args to the compressed file under |
| control of the format string, as in fprintf. gzprintf returns the number of |
| uncompressed bytes actually written (0 in case of error). |
| */ |
| |
| /* |
| Writes the given null-terminated string to the compressed file, excluding |
| the terminating null character. |
| gzputs returns the number of characters written, or -1 in case of error. |
| */ |
| |
| /* |
| Reads bytes from the compressed file until len-1 characters are read, or |
| a newline character is read and transferred to buf, or an end-of-file |
| condition is encountered. The string is then terminated with a null |
| character. |
| gzgets returns buf, or Z_NULL in case of error. |
| */ |
| |
| /* |
| Writes c, converted to an unsigned char, into the compressed file. |
| gzputc returns the value that was written, or -1 in case of error. |
| */ |
| |
| /* |
| Reads one byte from the compressed file. gzgetc returns this byte |
| or -1 in case of end of file or error. |
| */ |
| |
| /* |
| Flushes all pending output into the compressed file. The parameter |
| flush is as in the deflate() function. The return value is the zlib |
| error number (see function gzerror below). gzflush returns Z_OK if |
| the flush parameter is Z_FINISH and all output could be flushed. |
| gzflush should be called only when strictly necessary because it can |
| degrade compression. |
| */ |
| |
| /* |
| Sets the starting position for the next gzread or gzwrite on the |
| given compressed file. The offset represents a number of bytes in the |
| uncompressed data stream. The whence parameter is defined as in lseek(2); |
| the value SEEK_END is not supported. |
| If the file is opened for reading, this function is emulated but can be |
| extremely slow. If the file is opened for writing, only forward seeks are |
| supported; gzseek then compresses a sequence of zeroes up to the new |
| starting position. |
| |
| gzseek returns the resulting offset location as measured in bytes from |
| the beginning of the uncompressed stream, or -1 in case of error, in |
| particular if the file is opened for writing and the new starting position |
| would be before the current position. |
| */ |
| |
| /* |
| Rewinds the given file. This function is supported only for reading. |
| |
| gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) |
| */ |
| |
| /* |
| Returns the starting position for the next gzread or gzwrite on the |
| given compressed file. This position represents a number of bytes in the |
| uncompressed data stream. |
| |
| gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) |
| */ |
| |
| /* |
| Returns 1 when EOF has previously been detected reading the given |
| input stream, otherwise zero. |
| */ |
| |
| /* |
| Flushes all pending output if necessary, closes the compressed file |
| and deallocates all the (de)compression state. The return value is the zlib |
| error number (see function gzerror below). |
| */ |
| |
| /* |
| Returns the error message for the last error which occurred on the |
| given compressed file. errnum is set to zlib error number. If an |
| error occurred in the file system and not in the compression library, |
| errnum is set to Z_ERRNO and the application may consult errno |
| to get the exact error code. |
| */ |
| |
| /* checksum functions */ |
| |
| /* |
| These functions are not related to compression but are exported |
| anyway because they might be useful in applications using the |
| compression library. |
| */ |
| |
| ZEXTERN(uLong) adler32 OF((uLong adler, const Bytef *buf, uInt len)); |
| |
| /* |
| Update a running Adler-32 checksum with the bytes buf[0..len-1] and |
| return the updated checksum. If buf is NULL, this function returns |
| the required initial value for the checksum. |
| An Adler-32 checksum is almost as reliable as a CRC32 but can be computed |
| much faster. Usage example: |
| |
| uLong adler = adler32(0L, Z_NULL, 0); |
| |
| while (read_buffer(buffer, length) != EOF) { |
| adler = adler32(adler, buffer, length); |
| } |
| if (adler != original_adler) error(); |
| */ |
| |
| /* |
| Update a running crc with the bytes buf[0..len-1] and return the updated |
| crc. If buf is NULL, this function returns the required initial value |
| for the crc. Pre- and post-conditioning (one's complement) is performed |
| within this function so it shouldn't be done by the application. |
| Usage example: |
| |
| uLong crc = crc32(0L, Z_NULL, 0); |
| |
| while (read_buffer(buffer, length) != EOF) { |
| crc = crc32(crc, buffer, length); |
| } |
| if (crc != original_crc) error(); |
| */ |
| |
| |
| /* various hacks, don't look :) */ |
| |
| /* deflateInit and inflateInit are macros to allow checking the zlib version |
| * and the compiler's view of z_stream: |
| */ |
| ZEXTERN(int) inflateInit2_ OF((z_streamp strm, int windowBits, |
| const char *version, int stream_size)); |
| #define deflateInit(strm, level) \ |
| deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) |
| #define inflateInit(strm) \ |
| inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) |
| #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ |
| deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ |
| (strategy), ZLIB_VERSION, sizeof(z_stream)) |
| #define inflateInit2(strm, windowBits) \ |
| inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) |
| |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* _ZLIB_H */ |