| 0,0 → 1,1768 |
|---|
| /* zlib.h -- interface of the 'zlib' general purpose compression library |
| version 1.2.8, April 28th, 2013 |
| |
| Copyright (C) 1995-2013 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 http://tools.ietf.org/html/rfc1950 |
| (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format). |
| */ |
| |
| #ifndef ZLIB_H |
| #define ZLIB_H |
| |
| #include "zconf.h" |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| #define ZLIB_VERSION "1.2.8" |
| #define ZLIB_VERNUM 0x1280 |
| #define ZLIB_VER_MAJOR 1 |
| #define ZLIB_VER_MINOR 2 |
| #define ZLIB_VER_REVISION 8 |
| #define ZLIB_VER_SUBREVISION 0 |
| |
| /* |
| 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, |
| 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 compressed data format used by default by the in-memory functions is |
| the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped |
| around a deflate stream, which is itself documented in RFC 1951. |
| |
| The library also supports reading and writing files in gzip (.gz) format |
| with an interface similar to that of stdio using the functions that start |
| with "gz". The gzip format is different from the zlib format. gzip is a |
| gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. |
| |
| This library can optionally read and write gzip streams in memory as well. |
| |
| The zlib format was designed to be compact and fast for use in memory |
| and on communications channels. The gzip format was designed for single- |
| file compression on file systems, has a larger header than zlib to maintain |
| directory information, and uses a different, slower check method than zlib. |
| |
| 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 { |
| z_const Bytef *next_in; /* next input byte */ |
| uInt avail_in; /* number of bytes available at next_in */ |
| uLong total_in; /* total number 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 number of bytes output so far */ |
| |
| z_const 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: binary or text */ |
| uLong adler; /* adler32 value of the uncompressed data */ |
| uLong reserved; /* reserved for future use */ |
| } z_stream; |
| |
| typedef z_stream FAR *z_streamp; |
| |
| /* |
| gzip header information passed to and from zlib routines. See RFC 1952 |
| for more details on the meanings of these fields. |
| */ |
| typedef struct gz_header_s { |
| int text; /* true if compressed data believed to be text */ |
| uLong time; /* modification time */ |
| int xflags; /* extra flags (not used when writing a gzip file) */ |
| int os; /* operating system */ |
| Bytef *extra; /* pointer to extra field or Z_NULL if none */ |
| uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ |
| uInt extra_max; /* space at extra (only when reading header) */ |
| Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ |
| uInt name_max; /* space at name (only when reading header) */ |
| Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ |
| uInt comm_max; /* space at comment (only when reading header) */ |
| int hcrc; /* true if there was or will be a header crc */ |
| int done; /* true when done reading gzip header (not used |
| when writing a gzip file) */ |
| } gz_header; |
| |
| typedef gz_header FAR *gz_headerp; |
| |
| /* |
| 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 |
| #define Z_SYNC_FLUSH 2 |
| #define Z_FULL_FLUSH 3 |
| #define Z_FINISH 4 |
| #define Z_BLOCK 5 |
| #define Z_TREES 6 |
| /* Allowed flush values; see deflate() and inflate() 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_RLE 3 |
| #define Z_FIXED 4 |
| #define Z_DEFAULT_STRATEGY 0 |
| /* compression strategy; see deflateInit2() below for details */ |
| |
| #define Z_BINARY 0 |
| #define Z_TEXT 1 |
| #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ |
| #define Z_UNKNOWN 2 |
| /* Possible values of the data_type field (though see inflate()) */ |
| |
| #define Z_DEFLATED 8 |
| /* The deflate compression method (the only one supported in this version) */ |
| |
| #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ |
| |
| #define zlib_version zlibVersion() |
| /* for compatibility with versions < 1.0.2 */ |
| |
| |
| /* basic functions */ |
| |
| ZEXTERN const char * ZEXPORT zlibVersion OF((void)); |
| /* 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 ZEXPORT 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, or |
| 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(). |
| */ |
| |
| |
| ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); |
| /* |
| 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. |
| |
| Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to |
| decide how much data to accumulate before producing output, in order to |
| maximize compression. |
| |
| 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. This |
| completes the current deflate block and follows it with an empty stored block |
| that is three bits plus filler bits to the next byte, followed by four bytes |
| (00 00 ff ff). |
| |
| If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the |
| output buffer, but the output is not aligned to a byte boundary. All of the |
| input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. |
| This completes the current deflate block and follows it with an empty fixed |
| codes block that is 10 bits long. This assures that enough bytes are output |
| in order for the decompressor to finish the block before the empty fixed code |
| block. |
| |
| If flush is set to Z_BLOCK, a deflate block is completed and emitted, as |
| for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to |
| seven bits of the current block are held to be written as the next byte after |
| the next deflate block is completed. In this case, the decompressor may not |
| be provided enough bits at this point in order to complete decompression of |
| the data provided so far to the compressor. It may need to wait for the next |
| block to be emitted. This is for advanced applications that need to control |
| the emission of deflate blocks. |
| |
| 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 |
| 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). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that |
| avail_out is greater than six to avoid repeated flush markers due to |
| avail_out == 0 on return. |
| |
| 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 the |
| value returned by deflateBound (see below). Then deflate is guaranteed to |
| return Z_STREAM_END. If not enough output space is provided, deflate will |
| not return Z_STREAM_END, and 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 strm->data_type if it can make a good guess about |
| the input data type (Z_BINARY or Z_TEXT). 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 Z_NULL), Z_BUF_ERROR if no progress is possible |
| (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not |
| fatal, and deflate() can be called again with more input and more output |
| space to continue compressing. |
| */ |
| |
| |
| ZEXTERN int ZEXPORT deflateEnd 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. |
| |
| 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 ZEXPORT 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, or Z_STREAM_ERROR if the parameters are |
| invalid, such as a null pointer to the structure. msg is set to null if |
| there is no error message. inflateInit does not perform any decompression |
| apart from possibly reading the zlib header if present: actual decompression |
| will be done by inflate(). (So next_in and avail_in may be modified, but |
| next_out and avail_out are unused and unchanged.) The current implementation |
| of inflateInit() does not process any header information -- that is deferred |
| until inflate() is called. |
| */ |
| |
| |
| ZEXTERN int ZEXPORT 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 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. |
| |
| The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, |
| Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much |
| output as possible to the output buffer. Z_BLOCK requests that inflate() |
| stop if and when it gets to the next deflate block boundary. When decoding |
| the zlib or gzip format, this will cause inflate() to return immediately |
| after the header and before the first block. When doing a raw inflate, |
| inflate() will go ahead and process the first block, and will return when it |
| gets to the end of that block, or when it runs out of data. |
| |
| The Z_BLOCK option assists in appending to or combining deflate streams. |
| Also to assist in this, on return inflate() will set strm->data_type to the |
| number of unused bits in the last byte taken from strm->next_in, plus 64 if |
| inflate() is currently decoding the last block in the deflate stream, plus |
| 128 if inflate() returned immediately after decoding an end-of-block code or |
| decoding the complete header up to just before the first byte of the deflate |
| stream. The end-of-block will not be indicated until all of the uncompressed |
| data from that block has been written to strm->next_out. The number of |
| unused bits may in general be greater than seven, except when bit 7 of |
| data_type is set, in which case the number of unused bits will be less than |
| eight. data_type is set as noted here every time inflate() returns for all |
| flush options, and so can be used to determine the amount of currently |
| consumed input in bits. |
| |
| The Z_TREES option behaves as Z_BLOCK does, but it also returns when the |
| end of each deflate block header is reached, before any actual data in that |
| block is decoded. This allows the caller to determine the length of the |
| deflate block header for later use in random access within a deflate block. |
| 256 is added to the value of strm->data_type when inflate() returns |
| immediately after reaching the end of the deflate block header. |
| |
| 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 of the uncompressed data for the |
| operation to complete. (The size of the uncompressed data may have been |
| saved by the compressor for this purpose.) The use of Z_FINISH is not |
| required to perform an inflation in one step. However it may be used to |
| inform inflate that a faster approach can be used for the single inflate() |
| call. Z_FINISH also informs inflate to not maintain a sliding window if the |
| stream completes, which reduces inflate's memory footprint. If the stream |
| does not complete, either because not all of the stream is provided or not |
| enough output space is provided, then a sliding window will be allocated and |
| inflate() can be called again to continue the operation as if Z_NO_FLUSH had |
| been used. |
| |
| In this implementation, inflate() always flushes as much output as |
| possible to the output buffer, and always uses the faster approach on the |
| first call. So the effects of the flush parameter in this implementation are |
| on the return value of inflate() as noted below, when inflate() returns early |
| when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of |
| memory for a sliding window when Z_FINISH is used. |
| |
| If a preset dictionary is needed after this call (see inflateSetDictionary |
| below), inflate sets strm->adler to the Adler-32 checksum of the dictionary |
| chosen by the compressor and returns Z_NEED_DICT; otherwise it sets |
| strm->adler to the Adler-32 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() can decompress and check either zlib-wrapped or gzip-wrapped |
| deflate data. The header type is detected automatically, if requested when |
| initializing with inflateInit2(). Any information contained in the gzip |
| header is not retained, so applications that need that information should |
| instead use raw inflate, see inflateInit2() below, or inflateBack() and |
| perform their own processing of the gzip header and trailer. When processing |
| gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output |
| producted so far. The CRC-32 is checked against the gzip trailer. |
| |
| 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 check |
| value), Z_STREAM_ERROR if the stream structure was inconsistent (for example |
| next_in or next_out was Z_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. Note that Z_BUF_ERROR is not fatal, and |
| inflate() can be called again with more input and more output space to |
| continue decompressing. If Z_DATA_ERROR is returned, the application may |
| then call inflateSync() to look for a good compression block if a partial |
| recovery of the data is desired. |
| */ |
| |
| |
| ZEXTERN int ZEXPORT 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 ZEXPORT 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. |
| |
| windowBits can also be -8..-15 for raw deflate. In this case, -windowBits |
| determines the window size. deflate() will then generate raw deflate data |
| with no zlib header or trailer, and will not compute an adler32 check value. |
| |
| windowBits can also be greater than 15 for optional gzip encoding. Add |
| 16 to windowBits to write a simple gzip header and trailer around the |
| compressed data instead of a zlib wrapper. The gzip header will have no |
| file name, no extra data, no comment, no modification time (set to zero), no |
| header crc, and the operating system will be set to 255 (unknown). If a |
| gzip stream is being written, strm->adler is a crc32 instead of an adler32. |
| |
| 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), Z_HUFFMAN_ONLY to force Huffman encoding only (no |
| string match), or Z_RLE to limit match distances to one (run-length |
| encoding). 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_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as |
| fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The |
| strategy parameter only affects the compression ratio but not the |
| correctness of the compressed output even if it is not set appropriately. |
| Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler |
| decoder for special applications. |
| |
| deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid |
| method), or 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. deflateInit2 does not perform any |
| compression: this will be done by deflate(). |
| */ |
| |
| ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, |
| const Bytef *dictionary, |
| uInt dictLength)); |
| /* |
| Initializes the compression dictionary from the given byte sequence |
| without producing any compressed output. When using the zlib format, this |
| function must be called immediately after deflateInit, deflateInit2 or |
| deflateReset, and before any call of deflate. When doing raw deflate, this |
| function must be called either before any call of deflate, or immediately |
| after the completion of a deflate block, i.e. after all input has been |
| consumed and all output has been delivered when using any of the flush |
| options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. 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 |
| provided in deflateInit or deflateInit2. Thus the strings most likely to be |
| useful should be put at the end of the dictionary, not at the front. In |
| addition, the current implementation of deflate will use at most the window |
| size minus 262 bytes of the provided dictionary. |
| |
| 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.) If a raw deflate was requested, then the |
| adler32 value is not computed and strm->adler is not set. |
| |
| deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a |
| parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is |
| inconsistent (for example if deflate has already been called for this stream |
| or if not at a block boundary for raw deflate). deflateSetDictionary does |
| not perform any compression: this will be done by deflate(). |
| */ |
| |
| ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, |
| z_streamp source)); |
| /* |
| 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 Z_NULL). msg is left unchanged in both source and |
| destination. |
| */ |
| |
| ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); |
| /* |
| 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 Z_NULL). |
| */ |
| |
| ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, |
| int level, |
| int strategy)); |
| /* |
| 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 ZEXPORT deflateTune OF((z_streamp strm, |
| int good_length, |
| int max_lazy, |
| int nice_length, |
| int max_chain)); |
| /* |
| Fine tune deflate's internal compression parameters. This should only be |
| used by someone who understands the algorithm used by zlib's deflate for |
| searching for the best matching string, and even then only by the most |
| fanatic optimizer trying to squeeze out the last compressed bit for their |
| specific input data. Read the deflate.c source code for the meaning of the |
| max_lazy, good_length, nice_length, and max_chain parameters. |
| |
| deflateTune() can be called after deflateInit() or deflateInit2(), and |
| returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. |
| */ |
| |
| ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, |
| uLong sourceLen)); |
| /* |
| deflateBound() returns an upper bound on the compressed size after |
| deflation of sourceLen bytes. It must be called after deflateInit() or |
| deflateInit2(), and after deflateSetHeader(), if used. This would be used |
| to allocate an output buffer for deflation in a single pass, and so would be |
| called before deflate(). If that first deflate() call is provided the |
| sourceLen input bytes, an output buffer allocated to the size returned by |
| deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed |
| to return Z_STREAM_END. Note that it is possible for the compressed size to |
| be larger than the value returned by deflateBound() if flush options other |
| than Z_FINISH or Z_NO_FLUSH are used. |
| */ |
| |
| ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm, |
| unsigned *pending, |
| int *bits)); |
| /* |
| deflatePending() returns the number of bytes and bits of output that have |
| been generated, but not yet provided in the available output. The bytes not |
| provided would be due to the available output space having being consumed. |
| The number of bits of output not provided are between 0 and 7, where they |
| await more bits to join them in order to fill out a full byte. If pending |
| or bits are Z_NULL, then those values are not set. |
| |
| deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source |
| stream state was inconsistent. |
| */ |
| |
| ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, |
| int bits, |
| int value)); |
| /* |
| deflatePrime() inserts bits in the deflate output stream. The intent |
| is that this function is used to start off the deflate output with the bits |
| leftover from a previous deflate stream when appending to it. As such, this |
| function can only be used for raw deflate, and must be used before the first |
| deflate() call after a deflateInit2() or deflateReset(). bits must be less |
| than or equal to 16, and that many of the least significant bits of value |
| will be inserted in the output. |
| |
| deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough |
| room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the |
| source stream state was inconsistent. |
| */ |
| |
| ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, |
| gz_headerp head)); |
| /* |
| deflateSetHeader() provides gzip header information for when a gzip |
| stream is requested by deflateInit2(). deflateSetHeader() may be called |
| after deflateInit2() or deflateReset() and before the first call of |
| deflate(). The text, time, os, extra field, name, and comment information |
| in the provided gz_header structure are written to the gzip header (xflag is |
| ignored -- the extra flags are set according to the compression level). The |
| caller must assure that, if not Z_NULL, name and comment are terminated with |
| a zero byte, and that if extra is not Z_NULL, that extra_len bytes are |
| available there. If hcrc is true, a gzip header crc is included. Note that |
| the current versions of the command-line version of gzip (up through version |
| 1.3.x) do not support header crc's, and will report that it is a "multi-part |
| gzip file" and give up. |
| |
| If deflateSetHeader is not used, the default gzip header has text false, |
| the time set to zero, and os set to 255, with no extra, name, or comment |
| fields. The gzip header is returned to the default state by deflateReset(). |
| |
| deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source |
| stream state was inconsistent. |
| */ |
| |
| /* |
| ZEXTERN int ZEXPORT 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. windowBits must be greater than or equal to the windowBits value |
| provided to deflateInit2() while compressing, or it must be equal to 15 if |
| deflateInit2() was not used. 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. |
| |
| windowBits can also be zero to request that inflate use the window size in |
| the zlib header of the compressed stream. |
| |
| windowBits can also be -8..-15 for raw inflate. In this case, -windowBits |
| determines the window size. inflate() will then process raw deflate data, |
| not looking for a zlib or gzip header, not generating a check value, and not |
| looking for any check values for comparison at the end of the stream. This |
| is for use with other formats that use the deflate compressed data format |
| such as zip. Those formats provide their own check values. If a custom |
| format is developed using the raw deflate format for compressed data, it is |
| recommended that a check value such as an adler32 or a crc32 be applied to |
| the uncompressed data as is done in the zlib, gzip, and zip formats. For |
| most applications, the zlib format should be used as is. Note that comments |
| above on the use in deflateInit2() applies to the magnitude of windowBits. |
| |
| windowBits can also be greater than 15 for optional gzip decoding. Add |
| 32 to windowBits to enable zlib and gzip decoding with automatic header |
| detection, or add 16 to decode only the gzip format (the zlib format will |
| return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a |
| crc32 instead of an adler32. |
| |
| inflateInit2 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, or Z_STREAM_ERROR if the parameters are |
| invalid, such as a null pointer to the structure. msg is set to null if |
| there is no error message. inflateInit2 does not perform any decompression |
| apart from possibly reading the zlib header if present: actual decompression |
| will be done by inflate(). (So next_in and avail_in may be modified, but |
| next_out and avail_out are unused and unchanged.) The current implementation |
| of inflateInit2() does not process any header information -- that is |
| deferred until inflate() is called. |
| */ |
| |
| ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, |
| const Bytef *dictionary, |
| uInt dictLength)); |
| /* |
| Initializes the decompression dictionary from the given uncompressed byte |
| sequence. This function must be called immediately after a call of inflate, |
| if that call returned Z_NEED_DICT. The dictionary chosen by the compressor |
| can be determined from the adler32 value returned by that call of inflate. |
| The compressor and decompressor must use exactly the same dictionary (see |
| deflateSetDictionary). For raw inflate, this function can be called at any |
| time to set the dictionary. If the provided dictionary is smaller than the |
| window and there is already data in the window, then the provided dictionary |
| will amend what's there. The application must insure that the dictionary |
| that was used for compression is provided. |
| |
| inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a |
| parameter is invalid (e.g. dictionary being Z_NULL) 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(). |
| */ |
| |
| ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm, |
| Bytef *dictionary, |
| uInt *dictLength)); |
| /* |
| Returns the sliding dictionary being maintained by inflate. dictLength is |
| set to the number of bytes in the dictionary, and that many bytes are copied |
| to dictionary. dictionary must have enough space, where 32768 bytes is |
| always enough. If inflateGetDictionary() is called with dictionary equal to |
| Z_NULL, then only the dictionary length is returned, and nothing is copied. |
| Similary, if dictLength is Z_NULL, then it is not set. |
| |
| inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the |
| stream state is inconsistent. |
| */ |
| |
| ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); |
| /* |
| Skips invalid compressed data until a possible full flush point (see above |
| for the description of deflate with Z_FULL_FLUSH) can be found, or until all |
| available input is skipped. No output is provided. |
| |
| inflateSync searches for a 00 00 FF FF pattern in the compressed data. |
| All full flush points have this pattern, but not all occurrences of this |
| pattern are full flush points. |
| |
| inflateSync returns Z_OK if a possible 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 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 ZEXPORT inflateCopy OF((z_streamp dest, |
| z_streamp source)); |
| /* |
| Sets the destination stream as a complete copy of the source stream. |
| |
| This function can be useful when randomly accessing a large stream. The |
| first pass through the stream can periodically record the inflate state, |
| allowing restarting inflate at those points when randomly accessing the |
| stream. |
| |
| inflateCopy 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 Z_NULL). msg is left unchanged in both source and |
| destination. |
| */ |
| |
| ZEXTERN int ZEXPORT 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 Z_NULL). |
| */ |
| |
| ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm, |
| int windowBits)); |
| /* |
| This function is the same as inflateReset, but it also permits changing |
| the wrap and window size requests. The windowBits parameter is interpreted |
| the same as it is for inflateInit2. |
| |
| inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source |
| stream state was inconsistent (such as zalloc or state being Z_NULL), or if |
| the windowBits parameter is invalid. |
| */ |
| |
| ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, |
| int bits, |
| int value)); |
| /* |
| This function inserts bits in the inflate input stream. The intent is |
| that this function is used to start inflating at a bit position in the |
| middle of a byte. The provided bits will be used before any bytes are used |
| from next_in. This function should only be used with raw inflate, and |
| should be used before the first inflate() call after inflateInit2() or |
| inflateReset(). bits must be less than or equal to 16, and that many of the |
| least significant bits of value will be inserted in the input. |
| |
| If bits is negative, then the input stream bit buffer is emptied. Then |
| inflatePrime() can be called again to put bits in the buffer. This is used |
| to clear out bits leftover after feeding inflate a block description prior |
| to feeding inflate codes. |
| |
| inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source |
| stream state was inconsistent. |
| */ |
| |
| ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); |
| /* |
| This function returns two values, one in the lower 16 bits of the return |
| value, and the other in the remaining upper bits, obtained by shifting the |
| return value down 16 bits. If the upper value is -1 and the lower value is |
| zero, then inflate() is currently decoding information outside of a block. |
| If the upper value is -1 and the lower value is non-zero, then inflate is in |
| the middle of a stored block, with the lower value equaling the number of |
| bytes from the input remaining to copy. If the upper value is not -1, then |
| it is the number of bits back from the current bit position in the input of |
| the code (literal or length/distance pair) currently being processed. In |
| that case the lower value is the number of bytes already emitted for that |
| code. |
| |
| A code is being processed if inflate is waiting for more input to complete |
| decoding of the code, or if it has completed decoding but is waiting for |
| more output space to write the literal or match data. |
| |
| inflateMark() is used to mark locations in the input data for random |
| access, which may be at bit positions, and to note those cases where the |
| output of a code may span boundaries of random access blocks. The current |
| location in the input stream can be determined from avail_in and data_type |
| as noted in the description for the Z_BLOCK flush parameter for inflate. |
| |
| inflateMark returns the value noted above or -1 << 16 if the provided |
| source stream state was inconsistent. |
| */ |
| |
| ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, |
| gz_headerp head)); |
| /* |
| inflateGetHeader() requests that gzip header information be stored in the |
| provided gz_header structure. inflateGetHeader() may be called after |
| inflateInit2() or inflateReset(), and before the first call of inflate(). |
| As inflate() processes the gzip stream, head->done is zero until the header |
| is completed, at which time head->done is set to one. If a zlib stream is |
| being decoded, then head->done is set to -1 to indicate that there will be |
| no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be |
| used to force inflate() to return immediately after header processing is |
| complete and before any actual data is decompressed. |
| |
| The text, time, xflags, and os fields are filled in with the gzip header |
| contents. hcrc is set to true if there is a header CRC. (The header CRC |
| was valid if done is set to one.) If extra is not Z_NULL, then extra_max |
| contains the maximum number of bytes to write to extra. Once done is true, |
| extra_len contains the actual extra field length, and extra contains the |
| extra field, or that field truncated if extra_max is less than extra_len. |
| If name is not Z_NULL, then up to name_max characters are written there, |
| terminated with a zero unless the length is greater than name_max. If |
| comment is not Z_NULL, then up to comm_max characters are written there, |
| terminated with a zero unless the length is greater than comm_max. When any |
| of extra, name, or comment are not Z_NULL and the respective field is not |
| present in the header, then that field is set to Z_NULL to signal its |
| absence. This allows the use of deflateSetHeader() with the returned |
| structure to duplicate the header. However if those fields are set to |
| allocated memory, then the application will need to save those pointers |
| elsewhere so that they can be eventually freed. |
| |
| If inflateGetHeader is not used, then the header information is simply |
| discarded. The header is always checked for validity, including the header |
| CRC if present. inflateReset() will reset the process to discard the header |
| information. The application would need to call inflateGetHeader() again to |
| retrieve the header from the next gzip stream. |
| |
| inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source |
| stream state was inconsistent. |
| */ |
| |
| /* |
| ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, |
| unsigned char FAR *window)); |
| |
| Initialize the internal stream state for decompression using inflateBack() |
| calls. The fields zalloc, zfree and opaque in strm must be initialized |
| before the call. If zalloc and zfree are Z_NULL, then the default library- |
| derived memory allocation routines are used. windowBits is the base two |
| logarithm of the window size, in the range 8..15. window is a caller |
| supplied buffer of that size. Except for special applications where it is |
| assured that deflate was used with small window sizes, windowBits must be 15 |
| and a 32K byte window must be supplied to be able to decompress general |
| deflate streams. |
| |
| See inflateBack() for the usage of these routines. |
| |
| inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of |
| the parameters are invalid, Z_MEM_ERROR if the internal state could not be |
| allocated, or Z_VERSION_ERROR if the version of the library does not match |
| the version of the header file. |
| */ |
| |
| typedef unsigned (*in_func) OF((void FAR *, |
| z_const unsigned char FAR * FAR *)); |
| typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); |
| |
| ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, |
| in_func in, void FAR *in_desc, |
| out_func out, void FAR *out_desc)); |
| /* |
| inflateBack() does a raw inflate with a single call using a call-back |
| interface for input and output. This is potentially more efficient than |
| inflate() for file i/o applications, in that it avoids copying between the |
| output and the sliding window by simply making the window itself the output |
| buffer. inflate() can be faster on modern CPUs when used with large |
| buffers. inflateBack() trusts the application to not change the output |
| buffer passed by the output function, at least until inflateBack() returns. |
| |
| inflateBackInit() must be called first to allocate the internal state |
| and to initialize the state with the user-provided window buffer. |
| inflateBack() may then be used multiple times to inflate a complete, raw |
| deflate stream with each call. inflateBackEnd() is then called to free the |
| allocated state. |
| |
| A raw deflate stream is one with no zlib or gzip header or trailer. |
| This routine would normally be used in a utility that reads zip or gzip |
| files and writes out uncompressed files. The utility would decode the |
| header and process the trailer on its own, hence this routine expects only |
| the raw deflate stream to decompress. This is different from the normal |
| behavior of inflate(), which expects either a zlib or gzip header and |
| trailer around the deflate stream. |
| |
| inflateBack() uses two subroutines supplied by the caller that are then |
| called by inflateBack() for input and output. inflateBack() calls those |
| routines until it reads a complete deflate stream and writes out all of the |
| uncompressed data, or until it encounters an error. The function's |
| parameters and return types are defined above in the in_func and out_func |
| typedefs. inflateBack() will call in(in_desc, &buf) which should return the |
| number of bytes of provided input, and a pointer to that input in buf. If |
| there is no input available, in() must return zero--buf is ignored in that |
| case--and inflateBack() will return a buffer error. inflateBack() will call |
| out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() |
| should return zero on success, or non-zero on failure. If out() returns |
| non-zero, inflateBack() will return with an error. Neither in() nor out() |
| are permitted to change the contents of the window provided to |
| inflateBackInit(), which is also the buffer that out() uses to write from. |
| The length written by out() will be at most the window size. Any non-zero |
| amount of input may be provided by in(). |
| |
| For convenience, inflateBack() can be provided input on the first call by |
| setting strm->next_in and strm->avail_in. If that input is exhausted, then |
| in() will be called. Therefore strm->next_in must be initialized before |
| calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called |
| immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in |
| must also be initialized, and then if strm->avail_in is not zero, input will |
| initially be taken from strm->next_in[0 .. strm->avail_in - 1]. |
| |
| The in_desc and out_desc parameters of inflateBack() is passed as the |
| first parameter of in() and out() respectively when they are called. These |
| descriptors can be optionally used to pass any information that the caller- |
| supplied in() and out() functions need to do their job. |
| |
| On return, inflateBack() will set strm->next_in and strm->avail_in to |
| pass back any unused input that was provided by the last in() call. The |
| return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR |
| if in() or out() returned an error, Z_DATA_ERROR if there was a format error |
| in the deflate stream (in which case strm->msg is set to indicate the nature |
| of the error), or Z_STREAM_ERROR if the stream was not properly initialized. |
| In the case of Z_BUF_ERROR, an input or output error can be distinguished |
| using strm->next_in which will be Z_NULL only if in() returned an error. If |
| strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning |
| non-zero. (in() will always be called before out(), so strm->next_in is |
| assured to be defined if out() returns non-zero.) Note that inflateBack() |
| cannot return Z_OK. |
| */ |
| |
| ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); |
| /* |
| All memory allocated by inflateBackInit() is freed. |
| |
| inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream |
| state was inconsistent. |
| */ |
| |
| ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); |
| /* Return flags indicating compile-time options. |
| |
| Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: |
| 1.0: size of uInt |
| 3.2: size of uLong |
| 5.4: size of voidpf (pointer) |
| 7.6: size of z_off_t |
| |
| Compiler, assembler, and debug options: |
| 8: DEBUG |
| 9: ASMV or ASMINF -- use ASM code |
| 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention |
| 11: 0 (reserved) |
| |
| One-time table building (smaller code, but not thread-safe if true): |
| 12: BUILDFIXED -- build static block decoding tables when needed |
| 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed |
| 14,15: 0 (reserved) |
| |
| Library content (indicates missing functionality): |
| 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking |
| deflate code when not needed) |
| 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect |
| and decode gzip streams (to avoid linking crc code) |
| 18-19: 0 (reserved) |
| |
| Operation variations (changes in library functionality): |
| 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate |
| 21: FASTEST -- deflate algorithm with only one, lowest compression level |
| 22,23: 0 (reserved) |
| |
| The sprintf variant used by gzprintf (zero is best): |
| 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format |
| 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! |
| 26: 0 = returns value, 1 = void -- 1 means inferred string length returned |
| |
| Remainder: |
| 27-31: 0 (reserved) |
| */ |
| |
| #ifndef Z_SOLO |
| |
| /* 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 be modified if |
| you need special options. |
| */ |
| |
| ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, |
| const Bytef *source, uLong sourceLen)); |
| /* |
| 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 the value returned by |
| compressBound(sourceLen). Upon exit, destLen is the actual size of the |
| compressed buffer. |
| |
| 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. |
| */ |
| |
| ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, |
| const Bytef *source, uLong sourceLen, |
| int level)); |
| /* |
| 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 the value returned by |
| compressBound(sourceLen). 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. |
| */ |
| |
| ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); |
| /* |
| compressBound() returns an upper bound on the compressed size after |
| compress() or compress2() on sourceLen bytes. It would be used before a |
| compress() or compress2() call to allocate the destination buffer. |
| */ |
| |
| ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, |
| const Bytef *source, uLong sourceLen)); |
| /* |
| 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 uncompressed buffer. |
| |
| 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 or incomplete. In |
| the case where there is not enough room, uncompress() will fill the output |
| buffer with the uncompressed data up to that point. |
| */ |
| |
| /* gzip file access functions */ |
| |
| /* |
| This library supports reading and writing files in gzip (.gz) format with |
| an interface similar to that of stdio, using the functions that start with |
| "gz". The gzip format is different from the zlib format. gzip is a gzip |
| wrapper, documented in RFC 1952, wrapped around a deflate stream. |
| */ |
| |
| typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ |
| |
| /* |
| ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); |
| |
| 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", 'R' for run-length encoding as in "wb1R", or 'F' |
| for fixed code compression as in "wb9F". (See the description of |
| deflateInit2 for more information about the strategy parameter.) 'T' will |
| request transparent writing or appending with no compression and not using |
| the gzip format. |
| |
| "a" can be used instead of "w" to request that the gzip stream that will |
| be written be appended to the file. "+" will result in an error, since |
| reading and writing to the same gzip file is not supported. The addition of |
| "x" when writing will create the file exclusively, which fails if the file |
| already exists. On systems that support it, the addition of "e" when |
| reading or writing will set the flag to close the file on an execve() call. |
| |
| These functions, as well as gzip, will read and decode a sequence of gzip |
| streams in a file. The append function of gzopen() can be used to create |
| such a file. (Also see gzflush() for another way to do this.) When |
| appending, gzopen does not test whether the file begins with a gzip stream, |
| nor does it look for the end of the gzip streams to begin appending. gzopen |
| will simply append a gzip stream to the existing file. |
| |
| 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. When |
| reading, this will be detected automatically by looking for the magic two- |
| byte gzip header. |
| |
| gzopen returns NULL if the file could not be opened, if there was |
| insufficient memory to allocate the gzFile state, or if an invalid mode was |
| specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). |
| errno can be checked to determine if the reason gzopen failed was that the |
| file could not be opened. |
| */ |
| |
| ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); |
| /* |
| gzdopen associates a gzFile with the file descriptor fd. File descriptors |
| are obtained from calls like open, dup, creat, pipe or fileno (if 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 fd = dup(fd_keep); gz = gzdopen(fd, |
| mode);. The duplicated descriptor should be saved to avoid a leak, since |
| gzdopen does not close fd if it fails. If you are using fileno() to get the |
| file descriptor from a FILE *, then you will have to use dup() to avoid |
| double-close()ing the file descriptor. Both gzclose() and fclose() will |
| close the associated file descriptor, so they need to have different file |
| descriptors. |
| |
| gzdopen returns NULL if there was insufficient memory to allocate the |
| gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not |
| provided, or '+' was provided), or if fd is -1. The file descriptor is not |
| used until the next gz* read, write, seek, or close operation, so gzdopen |
| will not detect if fd is invalid (unless fd is -1). |
| */ |
| |
| ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size)); |
| /* |
| Set the internal buffer size used by this library's functions. The |
| default buffer size is 8192 bytes. This function must be called after |
| gzopen() or gzdopen(), and before any other calls that read or write the |
| file. The buffer memory allocation is always deferred to the first read or |
| write. Two buffers are allocated, either both of the specified size when |
| writing, or one of the specified size and the other twice that size when |
| reading. A larger buffer size of, for example, 64K or 128K bytes will |
| noticeably increase the speed of decompression (reading). |
| |
| The new buffer size also affects the maximum length for gzprintf(). |
| |
| gzbuffer() returns 0 on success, or -1 on failure, such as being called |
| too late. |
| */ |
| |
| ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); |
| /* |
| 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. |
| */ |
| |
| ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); |
| /* |
| Reads the given number of uncompressed bytes from the compressed file. If |
| the input file is not in gzip format, gzread copies the given number of |
| bytes into the buffer directly from the file. |
| |
| After reaching the end of a gzip stream in the input, gzread will continue |
| to read, looking for another gzip stream. Any number of gzip streams may be |
| concatenated in the input file, and will all be decompressed by gzread(). |
| If something other than a gzip stream is encountered after a gzip stream, |
| that remaining trailing garbage is ignored (and no error is returned). |
| |
| gzread can be used to read a gzip file that is being concurrently written. |
| Upon reaching the end of the input, gzread will return with the available |
| data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then |
| gzclearerr can be used to clear the end of file indicator in order to permit |
| gzread to be tried again. Z_OK indicates that a gzip stream was completed |
| on the last gzread. Z_BUF_ERROR indicates that the input file ended in the |
| middle of a gzip stream. Note that gzread does not return -1 in the event |
| of an incomplete gzip stream. This error is deferred until gzclose(), which |
| will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip |
| stream. Alternatively, gzerror can be used before gzclose to detect this |
| case. |
| |
| gzread returns the number of uncompressed bytes actually read, less than |
| len for end of file, or -1 for error. |
| */ |
| |
| ZEXTERN int ZEXPORT gzwrite OF((gzFile file, |
| voidpc buf, unsigned len)); |
| /* |
| Writes the given number of uncompressed bytes into the compressed file. |
| gzwrite returns the number of uncompressed bytes written or 0 in case of |
| error. |
| */ |
| |
| ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...)); |
| /* |
| Converts, formats, and writes the arguments to the compressed file under |
| control of the format string, as in fprintf. gzprintf returns the number of |
| uncompressed bytes actually written, or 0 in case of error. The number of |
| uncompressed bytes written is limited to 8191, or one less than the buffer |
| size given to gzbuffer(). The caller should assure that this limit is not |
| exceeded. If it is exceeded, then gzprintf() will return an error (0) with |
| nothing written. In this case, there may also be a buffer overflow with |
| unpredictable consequences, which is possible only if zlib was compiled with |
| the insecure functions sprintf() or vsprintf() because the secure snprintf() |
| or vsnprintf() functions were not available. This can be determined using |
| zlibCompileFlags(). |
| */ |
| |
| ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); |
| /* |
| 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. |
| */ |
| |
| ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); |
| /* |
| 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. If any characters are read or if len == 1, the |
| string is terminated with a null character. If no characters are read due |
| to an end-of-file or len < 1, then the buffer is left untouched. |
| |
| gzgets returns buf which is a null-terminated string, or it returns NULL |
| for end-of-file or in case of error. If there was an error, the contents at |
| buf are indeterminate. |
| */ |
| |
| ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); |
| /* |
| Writes c, converted to an unsigned char, into the compressed file. gzputc |
| returns the value that was written, or -1 in case of error. |
| */ |
| |
| ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); |
| /* |
| Reads one byte from the compressed file. gzgetc returns this byte or -1 |
| in case of end of file or error. This is implemented as a macro for speed. |
| As such, it does not do all of the checking the other functions do. I.e. |
| it does not check to see if file is NULL, nor whether the structure file |
| points to has been clobbered or not. |
| */ |
| |
| ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); |
| /* |
| Push one character back onto the stream to be read as the first character |
| on the next read. At least one character of push-back is allowed. |
| gzungetc() returns the character pushed, or -1 on failure. gzungetc() will |
| fail if c is -1, and may fail if a character has been pushed but not read |
| yet. If gzungetc is used immediately after gzopen or gzdopen, at least the |
| output buffer size of pushed characters is allowed. (See gzbuffer above.) |
| The pushed character will be discarded if the stream is repositioned with |
| gzseek() or gzrewind(). |
| */ |
| |
| ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); |
| /* |
| 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 is only permitted when writing. |
| |
| If the flush parameter is Z_FINISH, the remaining data is written and the |
| gzip stream is completed in the output. If gzwrite() is called again, a new |
| gzip stream will be started in the output. gzread() is able to read such |
| concatented gzip streams. |
| |
| gzflush should be called only when strictly necessary because it will |
| degrade compression if called too often. |
| */ |
| |
| /* |
| ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, |
| z_off_t offset, int whence)); |
| |
| 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. |
| */ |
| |
| ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); |
| /* |
| Rewinds the given file. This function is supported only for reading. |
| |
| gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) |
| */ |
| |
| /* |
| ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); |
| |
| 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, and is zero when starting, even if appending or |
| reading a gzip stream from the middle of a file using gzdopen(). |
| |
| gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) |
| */ |
| |
| /* |
| ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); |
| |
| Returns the current offset in the file being read or written. This offset |
| includes the count of bytes that precede the gzip stream, for example when |
| appending or when using gzdopen() for reading. When reading, the offset |
| does not include as yet unused buffered input. This information can be used |
| for a progress indicator. On error, gzoffset() returns -1. |
| */ |
| |
| ZEXTERN int ZEXPORT gzeof OF((gzFile file)); |
| /* |
| Returns true (1) if the end-of-file indicator has been set while reading, |
| false (0) otherwise. Note that the end-of-file indicator is set only if the |
| read tried to go past the end of the input, but came up short. Therefore, |
| just like feof(), gzeof() may return false even if there is no more data to |
| read, in the event that the last read request was for the exact number of |
| bytes remaining in the input file. This will happen if the input file size |
| is an exact multiple of the buffer size. |
| |
| If gzeof() returns true, then the read functions will return no more data, |
| unless the end-of-file indicator is reset by gzclearerr() and the input file |
| has grown since the previous end of file was detected. |
| */ |
| |
| ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); |
| /* |
| Returns true (1) if file is being copied directly while reading, or false |
| (0) if file is a gzip stream being decompressed. |
| |
| If the input file is empty, gzdirect() will return true, since the input |
| does not contain a gzip stream. |
| |
| If gzdirect() is used immediately after gzopen() or gzdopen() it will |
| cause buffers to be allocated to allow reading the file to determine if it |
| is a gzip file. Therefore if gzbuffer() is used, it should be called before |
| gzdirect(). |
| |
| When writing, gzdirect() returns true (1) if transparent writing was |
| requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: |
| gzdirect() is not needed when writing. Transparent writing must be |
| explicitly requested, so the application already knows the answer. When |
| linking statically, using gzdirect() will include all of the zlib code for |
| gzip file reading and decompression, which may not be desired.) |
| */ |
| |
| ZEXTERN int ZEXPORT gzclose OF((gzFile file)); |
| /* |
| Flushes all pending output if necessary, closes the compressed file and |
| deallocates the (de)compression state. Note that once file is closed, you |
| cannot call gzerror with file, since its structures have been deallocated. |
| gzclose must not be called more than once on the same file, just as free |
| must not be called more than once on the same allocation. |
| |
| gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a |
| file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the |
| last read ended in the middle of a gzip stream, or Z_OK on success. |
| */ |
| |
| ZEXTERN int ZEXPORT gzclose_r OF((gzFile file)); |
| ZEXTERN int ZEXPORT gzclose_w OF((gzFile file)); |
| /* |
| Same as gzclose(), but gzclose_r() is only for use when reading, and |
| gzclose_w() is only for use when writing or appending. The advantage to |
| using these instead of gzclose() is that they avoid linking in zlib |
| compression or decompression code that is not used when only reading or only |
| writing respectively. If gzclose() is used, then both compression and |
| decompression code will be included the application when linking to a static |
| zlib library. |
| */ |
| |
| ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); |
| /* |
| 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. |
| |
| The application must not modify the returned string. Future calls to |
| this function may invalidate the previously returned string. If file is |
| closed, then the string previously returned by gzerror will no longer be |
| available. |
| |
| gzerror() should be used to distinguish errors from end-of-file for those |
| functions above that do not distinguish those cases in their return values. |
| */ |
| |
| ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); |
| /* |
| Clears the error and end-of-file flags for file. This is analogous to the |
| clearerr() function in stdio. This is useful for continuing to read a gzip |
| file that is being written concurrently. |
| */ |
| |
| #endif /* !Z_SOLO */ |
| |
| /* 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 ZEXPORT 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 Z_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(); |
| */ |
| |
| /* |
| ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, |
| z_off_t len2)); |
| |
| Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 |
| and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for |
| each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of |
| seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note |
| that the z_off_t type (like off_t) is a signed integer. If len2 is |
| negative, the result has no meaning or utility. |
| */ |
| |
| ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); |
| /* |
| Update a running CRC-32 with the bytes buf[0..len-1] and return the |
| updated CRC-32. If buf is Z_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(); |
| */ |
| |
| /* |
| ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); |
| |
| Combine two CRC-32 check values into one. For two sequences of bytes, |
| seq1 and seq2 with lengths len1 and len2, CRC-32 check values were |
| calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 |
| check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and |
| len2. |
| */ |
| |
| |
| /* 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 ZEXPORT deflateInit_ OF((z_streamp strm, int level, |
| const char *version, int stream_size)); |
| ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, |
| const char *version, int stream_size)); |
| ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, |
| int windowBits, int memLevel, |
| int strategy, const char *version, |
| int stream_size)); |
| ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, |
| const char *version, int stream_size)); |
| ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, |
| unsigned char FAR *window, |
| const char *version, |
| int stream_size)); |
| #define deflateInit(strm, level) \ |
| deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) |
| #define inflateInit(strm) \ |
| inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) |
| #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ |
| deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ |
| (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) |
| #define inflateInit2(strm, windowBits) \ |
| inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ |
| (int)sizeof(z_stream)) |
| #define inflateBackInit(strm, windowBits, window) \ |
| inflateBackInit_((strm), (windowBits), (window), \ |
| ZLIB_VERSION, (int)sizeof(z_stream)) |
| |
| #ifndef Z_SOLO |
| |
| /* gzgetc() macro and its supporting function and exposed data structure. Note |
| * that the real internal state is much larger than the exposed structure. |
| * This abbreviated structure exposes just enough for the gzgetc() macro. The |
| * user should not mess with these exposed elements, since their names or |
| * behavior could change in the future, perhaps even capriciously. They can |
| * only be used by the gzgetc() macro. You have been warned. |
| */ |
| struct gzFile_s { |
| unsigned have; |
| unsigned char *next; |
| z_off64_t pos; |
| }; |
| ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */ |
| #ifdef Z_PREFIX_SET |
| # undef z_gzgetc |
| # define z_gzgetc(g) \ |
| ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g)) |
| #else |
| # define gzgetc(g) \ |
| ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g)) |
| #endif |
| |
| /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or |
| * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if |
| * both are true, the application gets the *64 functions, and the regular |
| * functions are changed to 64 bits) -- in case these are set on systems |
| * without large file support, _LFS64_LARGEFILE must also be true |
| */ |
| #ifdef Z_LARGE64 |
| ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); |
| ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); |
| ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); |
| ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); |
| ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); |
| ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); |
| #endif |
| |
| #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64) |
| # ifdef Z_PREFIX_SET |
| # define z_gzopen z_gzopen64 |
| # define z_gzseek z_gzseek64 |
| # define z_gztell z_gztell64 |
| # define z_gzoffset z_gzoffset64 |
| # define z_adler32_combine z_adler32_combine64 |
| # define z_crc32_combine z_crc32_combine64 |
| # else |
| # define gzopen gzopen64 |
| # define gzseek gzseek64 |
| # define gztell gztell64 |
| # define gzoffset gzoffset64 |
| # define adler32_combine adler32_combine64 |
| # define crc32_combine crc32_combine64 |
| # endif |
| # ifndef Z_LARGE64 |
| ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); |
| ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int)); |
| ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile)); |
| ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile)); |
| ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t)); |
| ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t)); |
| # endif |
| #else |
| ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); |
| ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); |
| ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); |
| ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); |
| ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); |
| ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); |
| #endif |
| |
| #else /* Z_SOLO */ |
| |
| ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); |
| ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); |
| |
| #endif /* !Z_SOLO */ |
| |
| /* hack for buggy compilers */ |
| #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) |
| struct internal_state {int dummy;}; |
| #endif |
| |
| /* undocumented functions */ |
| ZEXTERN const char * ZEXPORT zError OF((int)); |
| ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); |
| ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void)); |
| ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); |
| ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp)); |
| ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp)); |
| #if defined(_WIN32) && !defined(Z_SOLO) |
| ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path, |
| const char *mode)); |
| #endif |
| #if defined(STDC) || defined(Z_HAVE_STDARG_H) |
| # ifndef Z_SOLO |
| ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file, |
| const char *format, |
| va_list va)); |
| # endif |
| #endif |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* ZLIB_H */ |