michael@0: /* zlib.h -- interface of the 'zlib' general purpose compression library michael@0: version 1.2.8, April 28th, 2013 michael@0: michael@0: Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler michael@0: michael@0: This software is provided 'as-is', without any express or implied michael@0: warranty. In no event will the authors be held liable for any damages michael@0: arising from the use of this software. michael@0: michael@0: Permission is granted to anyone to use this software for any purpose, michael@0: including commercial applications, and to alter it and redistribute it michael@0: freely, subject to the following restrictions: michael@0: michael@0: 1. The origin of this software must not be misrepresented; you must not michael@0: claim that you wrote the original software. If you use this software michael@0: in a product, an acknowledgment in the product documentation would be michael@0: appreciated but is not required. michael@0: 2. Altered source versions must be plainly marked as such, and must not be michael@0: misrepresented as being the original software. michael@0: 3. This notice may not be removed or altered from any source distribution. michael@0: michael@0: Jean-loup Gailly Mark Adler michael@0: jloup@gzip.org madler@alumni.caltech.edu michael@0: michael@0: michael@0: The data format used by the zlib library is described by RFCs (Request for michael@0: Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950 michael@0: (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format). michael@0: */ michael@0: michael@0: #ifndef ZLIB_H michael@0: #define ZLIB_H michael@0: michael@0: #include "zconf.h" michael@0: michael@0: #ifdef __cplusplus michael@0: extern "C" { michael@0: #endif michael@0: michael@0: #define ZLIB_VERSION "1.2.8" michael@0: #define ZLIB_VERNUM 0x1280 michael@0: #define ZLIB_VER_MAJOR 1 michael@0: #define ZLIB_VER_MINOR 2 michael@0: #define ZLIB_VER_REVISION 8 michael@0: #define ZLIB_VER_SUBREVISION 0 michael@0: michael@0: /* michael@0: The 'zlib' compression library provides in-memory compression and michael@0: decompression functions, including integrity checks of the uncompressed data. michael@0: This version of the library supports only one compression method (deflation) michael@0: but other algorithms will be added later and will have the same stream michael@0: interface. michael@0: michael@0: Compression can be done in a single step if the buffers are large enough, michael@0: or can be done by repeated calls of the compression function. In the latter michael@0: case, the application must provide more input and/or consume the output michael@0: (providing more output space) before each call. michael@0: michael@0: The compressed data format used by default by the in-memory functions is michael@0: the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped michael@0: around a deflate stream, which is itself documented in RFC 1951. michael@0: michael@0: The library also supports reading and writing files in gzip (.gz) format michael@0: with an interface similar to that of stdio using the functions that start michael@0: with "gz". The gzip format is different from the zlib format. gzip is a michael@0: gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. michael@0: michael@0: This library can optionally read and write gzip streams in memory as well. michael@0: michael@0: The zlib format was designed to be compact and fast for use in memory michael@0: and on communications channels. The gzip format was designed for single- michael@0: file compression on file systems, has a larger header than zlib to maintain michael@0: directory information, and uses a different, slower check method than zlib. michael@0: michael@0: The library does not install any signal handler. The decoder checks michael@0: the consistency of the compressed data, so the library should never crash michael@0: even in case of corrupted input. michael@0: */ michael@0: michael@0: typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); michael@0: typedef void (*free_func) OF((voidpf opaque, voidpf address)); michael@0: michael@0: struct internal_state; michael@0: michael@0: typedef struct z_stream_s { michael@0: z_const Bytef *next_in; /* next input byte */ michael@0: uInt avail_in; /* number of bytes available at next_in */ michael@0: uLong total_in; /* total number of input bytes read so far */ michael@0: michael@0: Bytef *next_out; /* next output byte should be put there */ michael@0: uInt avail_out; /* remaining free space at next_out */ michael@0: uLong total_out; /* total number of bytes output so far */ michael@0: michael@0: z_const char *msg; /* last error message, NULL if no error */ michael@0: struct internal_state FAR *state; /* not visible by applications */ michael@0: michael@0: alloc_func zalloc; /* used to allocate the internal state */ michael@0: free_func zfree; /* used to free the internal state */ michael@0: voidpf opaque; /* private data object passed to zalloc and zfree */ michael@0: michael@0: int data_type; /* best guess about the data type: binary or text */ michael@0: uLong adler; /* adler32 value of the uncompressed data */ michael@0: uLong reserved; /* reserved for future use */ michael@0: } z_stream; michael@0: michael@0: typedef z_stream FAR *z_streamp; michael@0: michael@0: /* michael@0: gzip header information passed to and from zlib routines. See RFC 1952 michael@0: for more details on the meanings of these fields. michael@0: */ michael@0: typedef struct gz_header_s { michael@0: int text; /* true if compressed data believed to be text */ michael@0: uLong time; /* modification time */ michael@0: int xflags; /* extra flags (not used when writing a gzip file) */ michael@0: int os; /* operating system */ michael@0: Bytef *extra; /* pointer to extra field or Z_NULL if none */ michael@0: uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ michael@0: uInt extra_max; /* space at extra (only when reading header) */ michael@0: Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ michael@0: uInt name_max; /* space at name (only when reading header) */ michael@0: Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ michael@0: uInt comm_max; /* space at comment (only when reading header) */ michael@0: int hcrc; /* true if there was or will be a header crc */ michael@0: int done; /* true when done reading gzip header (not used michael@0: when writing a gzip file) */ michael@0: } gz_header; michael@0: michael@0: typedef gz_header FAR *gz_headerp; michael@0: michael@0: /* michael@0: The application must update next_in and avail_in when avail_in has dropped michael@0: to zero. It must update next_out and avail_out when avail_out has dropped michael@0: to zero. The application must initialize zalloc, zfree and opaque before michael@0: calling the init function. All other fields are set by the compression michael@0: library and must not be updated by the application. michael@0: michael@0: The opaque value provided by the application will be passed as the first michael@0: parameter for calls of zalloc and zfree. This can be useful for custom michael@0: memory management. The compression library attaches no meaning to the michael@0: opaque value. michael@0: michael@0: zalloc must return Z_NULL if there is not enough memory for the object. michael@0: If zlib is used in a multi-threaded application, zalloc and zfree must be michael@0: thread safe. michael@0: michael@0: On 16-bit systems, the functions zalloc and zfree must be able to allocate michael@0: exactly 65536 bytes, but will not be required to allocate more than this if michael@0: the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers michael@0: returned by zalloc for objects of exactly 65536 bytes *must* have their michael@0: offset normalized to zero. The default allocation function provided by this michael@0: library ensures this (see zutil.c). To reduce memory requirements and avoid michael@0: any allocation of 64K objects, at the expense of compression ratio, compile michael@0: the library with -DMAX_WBITS=14 (see zconf.h). michael@0: michael@0: The fields total_in and total_out can be used for statistics or progress michael@0: reports. After compression, total_in holds the total size of the michael@0: uncompressed data and may be saved for use in the decompressor (particularly michael@0: if the decompressor wants to decompress everything in a single step). michael@0: */ michael@0: michael@0: /* constants */ michael@0: michael@0: #define Z_NO_FLUSH 0 michael@0: #define Z_PARTIAL_FLUSH 1 michael@0: #define Z_SYNC_FLUSH 2 michael@0: #define Z_FULL_FLUSH 3 michael@0: #define Z_FINISH 4 michael@0: #define Z_BLOCK 5 michael@0: #define Z_TREES 6 michael@0: /* Allowed flush values; see deflate() and inflate() below for details */ michael@0: michael@0: #define Z_OK 0 michael@0: #define Z_STREAM_END 1 michael@0: #define Z_NEED_DICT 2 michael@0: #define Z_ERRNO (-1) michael@0: #define Z_STREAM_ERROR (-2) michael@0: #define Z_DATA_ERROR (-3) michael@0: #define Z_MEM_ERROR (-4) michael@0: #define Z_BUF_ERROR (-5) michael@0: #define Z_VERSION_ERROR (-6) michael@0: /* Return codes for the compression/decompression functions. Negative values michael@0: * are errors, positive values are used for special but normal events. michael@0: */ michael@0: michael@0: #define Z_NO_COMPRESSION 0 michael@0: #define Z_BEST_SPEED 1 michael@0: #define Z_BEST_COMPRESSION 9 michael@0: #define Z_DEFAULT_COMPRESSION (-1) michael@0: /* compression levels */ michael@0: michael@0: #define Z_FILTERED 1 michael@0: #define Z_HUFFMAN_ONLY 2 michael@0: #define Z_RLE 3 michael@0: #define Z_FIXED 4 michael@0: #define Z_DEFAULT_STRATEGY 0 michael@0: /* compression strategy; see deflateInit2() below for details */ michael@0: michael@0: #define Z_BINARY 0 michael@0: #define Z_TEXT 1 michael@0: #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ michael@0: #define Z_UNKNOWN 2 michael@0: /* Possible values of the data_type field (though see inflate()) */ michael@0: michael@0: #define Z_DEFLATED 8 michael@0: /* The deflate compression method (the only one supported in this version) */ michael@0: michael@0: #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ michael@0: michael@0: #define zlib_version zlibVersion() michael@0: /* for compatibility with versions < 1.0.2 */ michael@0: michael@0: michael@0: /* basic functions */ michael@0: michael@0: ZEXTERN const char * ZEXPORT zlibVersion OF((void)); michael@0: /* The application can compare zlibVersion and ZLIB_VERSION for consistency. michael@0: If the first character differs, the library code actually used is not michael@0: compatible with the zlib.h header file used by the application. This check michael@0: is automatically made by deflateInit and inflateInit. michael@0: */ michael@0: michael@0: /* michael@0: ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); michael@0: michael@0: Initializes the internal stream state for compression. The fields michael@0: zalloc, zfree and opaque must be initialized before by the caller. If michael@0: zalloc and zfree are set to Z_NULL, deflateInit updates them to use default michael@0: allocation functions. michael@0: michael@0: The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: michael@0: 1 gives best speed, 9 gives best compression, 0 gives no compression at all michael@0: (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION michael@0: requests a default compromise between speed and compression (currently michael@0: equivalent to level 6). michael@0: michael@0: deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough michael@0: memory, Z_STREAM_ERROR if level is not a valid compression level, or michael@0: Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible michael@0: with the version assumed by the caller (ZLIB_VERSION). msg is set to null michael@0: if there is no error message. deflateInit does not perform any compression: michael@0: this will be done by deflate(). michael@0: */ michael@0: michael@0: michael@0: ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); michael@0: /* michael@0: deflate compresses as much data as possible, and stops when the input michael@0: buffer becomes empty or the output buffer becomes full. It may introduce michael@0: some output latency (reading input without producing any output) except when michael@0: forced to flush. michael@0: michael@0: The detailed semantics are as follows. deflate performs one or both of the michael@0: following actions: michael@0: michael@0: - Compress more input starting at next_in and update next_in and avail_in michael@0: accordingly. If not all input can be processed (because there is not michael@0: enough room in the output buffer), next_in and avail_in are updated and michael@0: processing will resume at this point for the next call of deflate(). michael@0: michael@0: - Provide more output starting at next_out and update next_out and avail_out michael@0: accordingly. This action is forced if the parameter flush is non zero. michael@0: Forcing flush frequently degrades the compression ratio, so this parameter michael@0: should be set only when necessary (in interactive applications). Some michael@0: output may be provided even if flush is not set. michael@0: michael@0: Before the call of deflate(), the application should ensure that at least michael@0: one of the actions is possible, by providing more input and/or consuming more michael@0: output, and updating avail_in or avail_out accordingly; avail_out should michael@0: never be zero before the call. The application can consume the compressed michael@0: output when it wants, for example when the output buffer is full (avail_out michael@0: == 0), or after each call of deflate(). If deflate returns Z_OK and with michael@0: zero avail_out, it must be called again after making room in the output michael@0: buffer because there might be more output pending. michael@0: michael@0: Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to michael@0: decide how much data to accumulate before producing output, in order to michael@0: maximize compression. michael@0: michael@0: If the parameter flush is set to Z_SYNC_FLUSH, all pending output is michael@0: flushed to the output buffer and the output is aligned on a byte boundary, so michael@0: that the decompressor can get all input data available so far. (In michael@0: particular avail_in is zero after the call if enough output space has been michael@0: provided before the call.) Flushing may degrade compression for some michael@0: compression algorithms and so it should be used only when necessary. This michael@0: completes the current deflate block and follows it with an empty stored block michael@0: that is three bits plus filler bits to the next byte, followed by four bytes michael@0: (00 00 ff ff). michael@0: michael@0: If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the michael@0: output buffer, but the output is not aligned to a byte boundary. All of the michael@0: input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. michael@0: This completes the current deflate block and follows it with an empty fixed michael@0: codes block that is 10 bits long. This assures that enough bytes are output michael@0: in order for the decompressor to finish the block before the empty fixed code michael@0: block. michael@0: michael@0: If flush is set to Z_BLOCK, a deflate block is completed and emitted, as michael@0: for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to michael@0: seven bits of the current block are held to be written as the next byte after michael@0: the next deflate block is completed. In this case, the decompressor may not michael@0: be provided enough bits at this point in order to complete decompression of michael@0: the data provided so far to the compressor. It may need to wait for the next michael@0: block to be emitted. This is for advanced applications that need to control michael@0: the emission of deflate blocks. michael@0: michael@0: If flush is set to Z_FULL_FLUSH, all output is flushed as with michael@0: Z_SYNC_FLUSH, and the compression state is reset so that decompression can michael@0: restart from this point if previous compressed data has been damaged or if michael@0: random access is desired. Using Z_FULL_FLUSH too often can seriously degrade michael@0: compression. michael@0: michael@0: If deflate returns with avail_out == 0, this function must be called again michael@0: with the same value of the flush parameter and more output space (updated michael@0: avail_out), until the flush is complete (deflate returns with non-zero michael@0: avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that michael@0: avail_out is greater than six to avoid repeated flush markers due to michael@0: avail_out == 0 on return. michael@0: michael@0: If the parameter flush is set to Z_FINISH, pending input is processed, michael@0: pending output is flushed and deflate returns with Z_STREAM_END if there was michael@0: enough output space; if deflate returns with Z_OK, this function must be michael@0: called again with Z_FINISH and more output space (updated avail_out) but no michael@0: more input data, until it returns with Z_STREAM_END or an error. After michael@0: deflate has returned Z_STREAM_END, the only possible operations on the stream michael@0: are deflateReset or deflateEnd. michael@0: michael@0: Z_FINISH can be used immediately after deflateInit if all the compression michael@0: is to be done in a single step. In this case, avail_out must be at least the michael@0: value returned by deflateBound (see below). Then deflate is guaranteed to michael@0: return Z_STREAM_END. If not enough output space is provided, deflate will michael@0: not return Z_STREAM_END, and it must be called again as described above. michael@0: michael@0: deflate() sets strm->adler to the adler32 checksum of all input read michael@0: so far (that is, total_in bytes). michael@0: michael@0: deflate() may update strm->data_type if it can make a good guess about michael@0: the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered michael@0: binary. This field is only for information purposes and does not affect the michael@0: compression algorithm in any manner. michael@0: michael@0: deflate() returns Z_OK if some progress has been made (more input michael@0: processed or more output produced), Z_STREAM_END if all input has been michael@0: consumed and all output has been produced (only when flush is set to michael@0: Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example michael@0: if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible michael@0: (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not michael@0: fatal, and deflate() can be called again with more input and more output michael@0: space to continue compressing. michael@0: */ michael@0: michael@0: michael@0: ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); michael@0: /* michael@0: All dynamically allocated data structures for this stream are freed. michael@0: This function discards any unprocessed input and does not flush any pending michael@0: output. michael@0: michael@0: deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the michael@0: stream state was inconsistent, Z_DATA_ERROR if the stream was freed michael@0: prematurely (some input or output was discarded). In the error case, msg michael@0: may be set but then points to a static string (which must not be michael@0: deallocated). michael@0: */ michael@0: michael@0: michael@0: /* michael@0: ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); michael@0: michael@0: Initializes the internal stream state for decompression. The fields michael@0: next_in, avail_in, zalloc, zfree and opaque must be initialized before by michael@0: the caller. If next_in is not Z_NULL and avail_in is large enough (the michael@0: exact value depends on the compression method), inflateInit determines the michael@0: compression method from the zlib header and allocates all data structures michael@0: accordingly; otherwise the allocation will be deferred to the first call of michael@0: inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to michael@0: use default allocation functions. michael@0: michael@0: inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough michael@0: memory, Z_VERSION_ERROR if the zlib library version is incompatible with the michael@0: version assumed by the caller, or Z_STREAM_ERROR if the parameters are michael@0: invalid, such as a null pointer to the structure. msg is set to null if michael@0: there is no error message. inflateInit does not perform any decompression michael@0: apart from possibly reading the zlib header if present: actual decompression michael@0: will be done by inflate(). (So next_in and avail_in may be modified, but michael@0: next_out and avail_out are unused and unchanged.) The current implementation michael@0: of inflateInit() does not process any header information -- that is deferred michael@0: until inflate() is called. michael@0: */ michael@0: michael@0: michael@0: ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); michael@0: /* michael@0: inflate decompresses as much data as possible, and stops when the input michael@0: buffer becomes empty or the output buffer becomes full. It may introduce michael@0: some output latency (reading input without producing any output) except when michael@0: forced to flush. michael@0: michael@0: The detailed semantics are as follows. inflate performs one or both of the michael@0: following actions: michael@0: michael@0: - Decompress more input starting at next_in and update next_in and avail_in michael@0: accordingly. If not all input can be processed (because there is not michael@0: enough room in the output buffer), next_in is updated and processing will michael@0: resume at this point for the next call of inflate(). michael@0: michael@0: - Provide more output starting at next_out and update next_out and avail_out michael@0: accordingly. inflate() provides as much output as possible, until there is michael@0: no more input data or no more space in the output buffer (see below about michael@0: the flush parameter). michael@0: michael@0: Before the call of inflate(), the application should ensure that at least michael@0: one of the actions is possible, by providing more input and/or consuming more michael@0: output, and updating the next_* and avail_* values accordingly. The michael@0: application can consume the uncompressed output when it wants, for example michael@0: when the output buffer is full (avail_out == 0), or after each call of michael@0: inflate(). If inflate returns Z_OK and with zero avail_out, it must be michael@0: called again after making room in the output buffer because there might be michael@0: more output pending. michael@0: michael@0: The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, michael@0: Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much michael@0: output as possible to the output buffer. Z_BLOCK requests that inflate() michael@0: stop if and when it gets to the next deflate block boundary. When decoding michael@0: the zlib or gzip format, this will cause inflate() to return immediately michael@0: after the header and before the first block. When doing a raw inflate, michael@0: inflate() will go ahead and process the first block, and will return when it michael@0: gets to the end of that block, or when it runs out of data. michael@0: michael@0: The Z_BLOCK option assists in appending to or combining deflate streams. michael@0: Also to assist in this, on return inflate() will set strm->data_type to the michael@0: number of unused bits in the last byte taken from strm->next_in, plus 64 if michael@0: inflate() is currently decoding the last block in the deflate stream, plus michael@0: 128 if inflate() returned immediately after decoding an end-of-block code or michael@0: decoding the complete header up to just before the first byte of the deflate michael@0: stream. The end-of-block will not be indicated until all of the uncompressed michael@0: data from that block has been written to strm->next_out. The number of michael@0: unused bits may in general be greater than seven, except when bit 7 of michael@0: data_type is set, in which case the number of unused bits will be less than michael@0: eight. data_type is set as noted here every time inflate() returns for all michael@0: flush options, and so can be used to determine the amount of currently michael@0: consumed input in bits. michael@0: michael@0: The Z_TREES option behaves as Z_BLOCK does, but it also returns when the michael@0: end of each deflate block header is reached, before any actual data in that michael@0: block is decoded. This allows the caller to determine the length of the michael@0: deflate block header for later use in random access within a deflate block. michael@0: 256 is added to the value of strm->data_type when inflate() returns michael@0: immediately after reaching the end of the deflate block header. michael@0: michael@0: inflate() should normally be called until it returns Z_STREAM_END or an michael@0: error. However if all decompression is to be performed in a single step (a michael@0: single call of inflate), the parameter flush should be set to Z_FINISH. In michael@0: this case all pending input is processed and all pending output is flushed; michael@0: avail_out must be large enough to hold all of the uncompressed data for the michael@0: operation to complete. (The size of the uncompressed data may have been michael@0: saved by the compressor for this purpose.) The use of Z_FINISH is not michael@0: required to perform an inflation in one step. However it may be used to michael@0: inform inflate that a faster approach can be used for the single inflate() michael@0: call. Z_FINISH also informs inflate to not maintain a sliding window if the michael@0: stream completes, which reduces inflate's memory footprint. If the stream michael@0: does not complete, either because not all of the stream is provided or not michael@0: enough output space is provided, then a sliding window will be allocated and michael@0: inflate() can be called again to continue the operation as if Z_NO_FLUSH had michael@0: been used. michael@0: michael@0: In this implementation, inflate() always flushes as much output as michael@0: possible to the output buffer, and always uses the faster approach on the michael@0: first call. So the effects of the flush parameter in this implementation are michael@0: on the return value of inflate() as noted below, when inflate() returns early michael@0: when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of michael@0: memory for a sliding window when Z_FINISH is used. michael@0: michael@0: If a preset dictionary is needed after this call (see inflateSetDictionary michael@0: below), inflate sets strm->adler to the Adler-32 checksum of the dictionary michael@0: chosen by the compressor and returns Z_NEED_DICT; otherwise it sets michael@0: strm->adler to the Adler-32 checksum of all output produced so far (that is, michael@0: total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described michael@0: below. At the end of the stream, inflate() checks that its computed adler32 michael@0: checksum is equal to that saved by the compressor and returns Z_STREAM_END michael@0: only if the checksum is correct. michael@0: michael@0: inflate() can decompress and check either zlib-wrapped or gzip-wrapped michael@0: deflate data. The header type is detected automatically, if requested when michael@0: initializing with inflateInit2(). Any information contained in the gzip michael@0: header is not retained, so applications that need that information should michael@0: instead use raw inflate, see inflateInit2() below, or inflateBack() and michael@0: perform their own processing of the gzip header and trailer. When processing michael@0: gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output michael@0: producted so far. The CRC-32 is checked against the gzip trailer. michael@0: michael@0: inflate() returns Z_OK if some progress has been made (more input processed michael@0: or more output produced), Z_STREAM_END if the end of the compressed data has michael@0: been reached and all uncompressed output has been produced, Z_NEED_DICT if a michael@0: preset dictionary is needed at this point, Z_DATA_ERROR if the input data was michael@0: corrupted (input stream not conforming to the zlib format or incorrect check michael@0: value), Z_STREAM_ERROR if the stream structure was inconsistent (for example michael@0: next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory, michael@0: Z_BUF_ERROR if no progress is possible or if there was not enough room in the michael@0: output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and michael@0: inflate() can be called again with more input and more output space to michael@0: continue decompressing. If Z_DATA_ERROR is returned, the application may michael@0: then call inflateSync() to look for a good compression block if a partial michael@0: recovery of the data is desired. michael@0: */ michael@0: michael@0: michael@0: ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); michael@0: /* michael@0: All dynamically allocated data structures for this stream are freed. michael@0: This function discards any unprocessed input and does not flush any pending michael@0: output. michael@0: michael@0: inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state michael@0: was inconsistent. In the error case, msg may be set but then points to a michael@0: static string (which must not be deallocated). michael@0: */ michael@0: michael@0: michael@0: /* Advanced functions */ michael@0: michael@0: /* michael@0: The following functions are needed only in some special applications. michael@0: */ michael@0: michael@0: /* michael@0: ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, michael@0: int level, michael@0: int method, michael@0: int windowBits, michael@0: int memLevel, michael@0: int strategy)); michael@0: michael@0: This is another version of deflateInit with more compression options. The michael@0: fields next_in, zalloc, zfree and opaque must be initialized before by the michael@0: caller. michael@0: michael@0: The method parameter is the compression method. It must be Z_DEFLATED in michael@0: this version of the library. michael@0: michael@0: The windowBits parameter is the base two logarithm of the window size michael@0: (the size of the history buffer). It should be in the range 8..15 for this michael@0: version of the library. Larger values of this parameter result in better michael@0: compression at the expense of memory usage. The default value is 15 if michael@0: deflateInit is used instead. michael@0: michael@0: windowBits can also be -8..-15 for raw deflate. In this case, -windowBits michael@0: determines the window size. deflate() will then generate raw deflate data michael@0: with no zlib header or trailer, and will not compute an adler32 check value. michael@0: michael@0: windowBits can also be greater than 15 for optional gzip encoding. Add michael@0: 16 to windowBits to write a simple gzip header and trailer around the michael@0: compressed data instead of a zlib wrapper. The gzip header will have no michael@0: file name, no extra data, no comment, no modification time (set to zero), no michael@0: header crc, and the operating system will be set to 255 (unknown). If a michael@0: gzip stream is being written, strm->adler is a crc32 instead of an adler32. michael@0: michael@0: The memLevel parameter specifies how much memory should be allocated michael@0: for the internal compression state. memLevel=1 uses minimum memory but is michael@0: slow and reduces compression ratio; memLevel=9 uses maximum memory for michael@0: optimal speed. The default value is 8. See zconf.h for total memory usage michael@0: as a function of windowBits and memLevel. michael@0: michael@0: The strategy parameter is used to tune the compression algorithm. Use the michael@0: value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a michael@0: filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no michael@0: string match), or Z_RLE to limit match distances to one (run-length michael@0: encoding). Filtered data consists mostly of small values with a somewhat michael@0: random distribution. In this case, the compression algorithm is tuned to michael@0: compress them better. The effect of Z_FILTERED is to force more Huffman michael@0: coding and less string matching; it is somewhat intermediate between michael@0: Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as michael@0: fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The michael@0: strategy parameter only affects the compression ratio but not the michael@0: correctness of the compressed output even if it is not set appropriately. michael@0: Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler michael@0: decoder for special applications. michael@0: michael@0: deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough michael@0: memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid michael@0: method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is michael@0: incompatible with the version assumed by the caller (ZLIB_VERSION). msg is michael@0: set to null if there is no error message. deflateInit2 does not perform any michael@0: compression: this will be done by deflate(). michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, michael@0: const Bytef *dictionary, michael@0: uInt dictLength)); michael@0: /* michael@0: Initializes the compression dictionary from the given byte sequence michael@0: without producing any compressed output. When using the zlib format, this michael@0: function must be called immediately after deflateInit, deflateInit2 or michael@0: deflateReset, and before any call of deflate. When doing raw deflate, this michael@0: function must be called either before any call of deflate, or immediately michael@0: after the completion of a deflate block, i.e. after all input has been michael@0: consumed and all output has been delivered when using any of the flush michael@0: options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The michael@0: compressor and decompressor must use exactly the same dictionary (see michael@0: inflateSetDictionary). michael@0: michael@0: The dictionary should consist of strings (byte sequences) that are likely michael@0: to be encountered later in the data to be compressed, with the most commonly michael@0: used strings preferably put towards the end of the dictionary. Using a michael@0: dictionary is most useful when the data to be compressed is short and can be michael@0: predicted with good accuracy; the data can then be compressed better than michael@0: with the default empty dictionary. michael@0: michael@0: Depending on the size of the compression data structures selected by michael@0: deflateInit or deflateInit2, a part of the dictionary may in effect be michael@0: discarded, for example if the dictionary is larger than the window size michael@0: provided in deflateInit or deflateInit2. Thus the strings most likely to be michael@0: useful should be put at the end of the dictionary, not at the front. In michael@0: addition, the current implementation of deflate will use at most the window michael@0: size minus 262 bytes of the provided dictionary. michael@0: michael@0: Upon return of this function, strm->adler is set to the adler32 value michael@0: of the dictionary; the decompressor may later use this value to determine michael@0: which dictionary has been used by the compressor. (The adler32 value michael@0: applies to the whole dictionary even if only a subset of the dictionary is michael@0: actually used by the compressor.) If a raw deflate was requested, then the michael@0: adler32 value is not computed and strm->adler is not set. michael@0: michael@0: deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a michael@0: parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is michael@0: inconsistent (for example if deflate has already been called for this stream michael@0: or if not at a block boundary for raw deflate). deflateSetDictionary does michael@0: not perform any compression: this will be done by deflate(). michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, michael@0: z_streamp source)); michael@0: /* michael@0: Sets the destination stream as a complete copy of the source stream. michael@0: michael@0: This function can be useful when several compression strategies will be michael@0: tried, for example when there are several ways of pre-processing the input michael@0: data with a filter. The streams that will be discarded should then be freed michael@0: by calling deflateEnd. Note that deflateCopy duplicates the internal michael@0: compression state which can be quite large, so this strategy is slow and can michael@0: consume lots of memory. michael@0: michael@0: deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not michael@0: enough memory, Z_STREAM_ERROR if the source stream state was inconsistent michael@0: (such as zalloc being Z_NULL). msg is left unchanged in both source and michael@0: destination. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); michael@0: /* michael@0: This function is equivalent to deflateEnd followed by deflateInit, michael@0: but does not free and reallocate all the internal compression state. The michael@0: stream will keep the same compression level and any other attributes that michael@0: may have been set by deflateInit2. michael@0: michael@0: deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source michael@0: stream state was inconsistent (such as zalloc or state being Z_NULL). michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, michael@0: int level, michael@0: int strategy)); michael@0: /* michael@0: Dynamically update the compression level and compression strategy. The michael@0: interpretation of level and strategy is as in deflateInit2. This can be michael@0: used to switch between compression and straight copy of the input data, or michael@0: to switch to a different kind of input data requiring a different strategy. michael@0: If the compression level is changed, the input available so far is michael@0: compressed with the old level (and may be flushed); the new level will take michael@0: effect only at the next call of deflate(). michael@0: michael@0: Before the call of deflateParams, the stream state must be set as for michael@0: a call of deflate(), since the currently available input may have to be michael@0: compressed and flushed. In particular, strm->avail_out must be non-zero. michael@0: michael@0: deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source michael@0: stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if michael@0: strm->avail_out was zero. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, michael@0: int good_length, michael@0: int max_lazy, michael@0: int nice_length, michael@0: int max_chain)); michael@0: /* michael@0: Fine tune deflate's internal compression parameters. This should only be michael@0: used by someone who understands the algorithm used by zlib's deflate for michael@0: searching for the best matching string, and even then only by the most michael@0: fanatic optimizer trying to squeeze out the last compressed bit for their michael@0: specific input data. Read the deflate.c source code for the meaning of the michael@0: max_lazy, good_length, nice_length, and max_chain parameters. michael@0: michael@0: deflateTune() can be called after deflateInit() or deflateInit2(), and michael@0: returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. michael@0: */ michael@0: michael@0: ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, michael@0: uLong sourceLen)); michael@0: /* michael@0: deflateBound() returns an upper bound on the compressed size after michael@0: deflation of sourceLen bytes. It must be called after deflateInit() or michael@0: deflateInit2(), and after deflateSetHeader(), if used. This would be used michael@0: to allocate an output buffer for deflation in a single pass, and so would be michael@0: called before deflate(). If that first deflate() call is provided the michael@0: sourceLen input bytes, an output buffer allocated to the size returned by michael@0: deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed michael@0: to return Z_STREAM_END. Note that it is possible for the compressed size to michael@0: be larger than the value returned by deflateBound() if flush options other michael@0: than Z_FINISH or Z_NO_FLUSH are used. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm, michael@0: unsigned *pending, michael@0: int *bits)); michael@0: /* michael@0: deflatePending() returns the number of bytes and bits of output that have michael@0: been generated, but not yet provided in the available output. The bytes not michael@0: provided would be due to the available output space having being consumed. michael@0: The number of bits of output not provided are between 0 and 7, where they michael@0: await more bits to join them in order to fill out a full byte. If pending michael@0: or bits are Z_NULL, then those values are not set. michael@0: michael@0: deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source michael@0: stream state was inconsistent. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, michael@0: int bits, michael@0: int value)); michael@0: /* michael@0: deflatePrime() inserts bits in the deflate output stream. The intent michael@0: is that this function is used to start off the deflate output with the bits michael@0: leftover from a previous deflate stream when appending to it. As such, this michael@0: function can only be used for raw deflate, and must be used before the first michael@0: deflate() call after a deflateInit2() or deflateReset(). bits must be less michael@0: than or equal to 16, and that many of the least significant bits of value michael@0: will be inserted in the output. michael@0: michael@0: deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough michael@0: room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the michael@0: source stream state was inconsistent. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, michael@0: gz_headerp head)); michael@0: /* michael@0: deflateSetHeader() provides gzip header information for when a gzip michael@0: stream is requested by deflateInit2(). deflateSetHeader() may be called michael@0: after deflateInit2() or deflateReset() and before the first call of michael@0: deflate(). The text, time, os, extra field, name, and comment information michael@0: in the provided gz_header structure are written to the gzip header (xflag is michael@0: ignored -- the extra flags are set according to the compression level). The michael@0: caller must assure that, if not Z_NULL, name and comment are terminated with michael@0: a zero byte, and that if extra is not Z_NULL, that extra_len bytes are michael@0: available there. If hcrc is true, a gzip header crc is included. Note that michael@0: the current versions of the command-line version of gzip (up through version michael@0: 1.3.x) do not support header crc's, and will report that it is a "multi-part michael@0: gzip file" and give up. michael@0: michael@0: If deflateSetHeader is not used, the default gzip header has text false, michael@0: the time set to zero, and os set to 255, with no extra, name, or comment michael@0: fields. The gzip header is returned to the default state by deflateReset(). michael@0: michael@0: deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source michael@0: stream state was inconsistent. michael@0: */ michael@0: michael@0: /* michael@0: ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, michael@0: int windowBits)); michael@0: michael@0: This is another version of inflateInit with an extra parameter. The michael@0: fields next_in, avail_in, zalloc, zfree and opaque must be initialized michael@0: before by the caller. michael@0: michael@0: The windowBits parameter is the base two logarithm of the maximum window michael@0: size (the size of the history buffer). It should be in the range 8..15 for michael@0: this version of the library. The default value is 15 if inflateInit is used michael@0: instead. windowBits must be greater than or equal to the windowBits value michael@0: provided to deflateInit2() while compressing, or it must be equal to 15 if michael@0: deflateInit2() was not used. If a compressed stream with a larger window michael@0: size is given as input, inflate() will return with the error code michael@0: Z_DATA_ERROR instead of trying to allocate a larger window. michael@0: michael@0: windowBits can also be zero to request that inflate use the window size in michael@0: the zlib header of the compressed stream. michael@0: michael@0: windowBits can also be -8..-15 for raw inflate. In this case, -windowBits michael@0: determines the window size. inflate() will then process raw deflate data, michael@0: not looking for a zlib or gzip header, not generating a check value, and not michael@0: looking for any check values for comparison at the end of the stream. This michael@0: is for use with other formats that use the deflate compressed data format michael@0: such as zip. Those formats provide their own check values. If a custom michael@0: format is developed using the raw deflate format for compressed data, it is michael@0: recommended that a check value such as an adler32 or a crc32 be applied to michael@0: the uncompressed data as is done in the zlib, gzip, and zip formats. For michael@0: most applications, the zlib format should be used as is. Note that comments michael@0: above on the use in deflateInit2() applies to the magnitude of windowBits. michael@0: michael@0: windowBits can also be greater than 15 for optional gzip decoding. Add michael@0: 32 to windowBits to enable zlib and gzip decoding with automatic header michael@0: detection, or add 16 to decode only the gzip format (the zlib format will michael@0: return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a michael@0: crc32 instead of an adler32. michael@0: michael@0: inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough michael@0: memory, Z_VERSION_ERROR if the zlib library version is incompatible with the michael@0: version assumed by the caller, or Z_STREAM_ERROR if the parameters are michael@0: invalid, such as a null pointer to the structure. msg is set to null if michael@0: there is no error message. inflateInit2 does not perform any decompression michael@0: apart from possibly reading the zlib header if present: actual decompression michael@0: will be done by inflate(). (So next_in and avail_in may be modified, but michael@0: next_out and avail_out are unused and unchanged.) The current implementation michael@0: of inflateInit2() does not process any header information -- that is michael@0: deferred until inflate() is called. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, michael@0: const Bytef *dictionary, michael@0: uInt dictLength)); michael@0: /* michael@0: Initializes the decompression dictionary from the given uncompressed byte michael@0: sequence. This function must be called immediately after a call of inflate, michael@0: if that call returned Z_NEED_DICT. The dictionary chosen by the compressor michael@0: can be determined from the adler32 value returned by that call of inflate. michael@0: The compressor and decompressor must use exactly the same dictionary (see michael@0: deflateSetDictionary). For raw inflate, this function can be called at any michael@0: time to set the dictionary. If the provided dictionary is smaller than the michael@0: window and there is already data in the window, then the provided dictionary michael@0: will amend what's there. The application must insure that the dictionary michael@0: that was used for compression is provided. michael@0: michael@0: inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a michael@0: parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is michael@0: inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the michael@0: expected one (incorrect adler32 value). inflateSetDictionary does not michael@0: perform any decompression: this will be done by subsequent calls of michael@0: inflate(). michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm, michael@0: Bytef *dictionary, michael@0: uInt *dictLength)); michael@0: /* michael@0: Returns the sliding dictionary being maintained by inflate. dictLength is michael@0: set to the number of bytes in the dictionary, and that many bytes are copied michael@0: to dictionary. dictionary must have enough space, where 32768 bytes is michael@0: always enough. If inflateGetDictionary() is called with dictionary equal to michael@0: Z_NULL, then only the dictionary length is returned, and nothing is copied. michael@0: Similary, if dictLength is Z_NULL, then it is not set. michael@0: michael@0: inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the michael@0: stream state is inconsistent. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); michael@0: /* michael@0: Skips invalid compressed data until a possible full flush point (see above michael@0: for the description of deflate with Z_FULL_FLUSH) can be found, or until all michael@0: available input is skipped. No output is provided. michael@0: michael@0: inflateSync searches for a 00 00 FF FF pattern in the compressed data. michael@0: All full flush points have this pattern, but not all occurrences of this michael@0: pattern are full flush points. michael@0: michael@0: inflateSync returns Z_OK if a possible full flush point has been found, michael@0: Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point michael@0: has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. michael@0: In the success case, the application may save the current current value of michael@0: total_in which indicates where valid compressed data was found. In the michael@0: error case, the application may repeatedly call inflateSync, providing more michael@0: input each time, until success or end of the input data. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, michael@0: z_streamp source)); michael@0: /* michael@0: Sets the destination stream as a complete copy of the source stream. michael@0: michael@0: This function can be useful when randomly accessing a large stream. The michael@0: first pass through the stream can periodically record the inflate state, michael@0: allowing restarting inflate at those points when randomly accessing the michael@0: stream. michael@0: michael@0: inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not michael@0: enough memory, Z_STREAM_ERROR if the source stream state was inconsistent michael@0: (such as zalloc being Z_NULL). msg is left unchanged in both source and michael@0: destination. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); michael@0: /* michael@0: This function is equivalent to inflateEnd followed by inflateInit, michael@0: but does not free and reallocate all the internal decompression state. The michael@0: stream will keep attributes that may have been set by inflateInit2. michael@0: michael@0: inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source michael@0: stream state was inconsistent (such as zalloc or state being Z_NULL). michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm, michael@0: int windowBits)); michael@0: /* michael@0: This function is the same as inflateReset, but it also permits changing michael@0: the wrap and window size requests. The windowBits parameter is interpreted michael@0: the same as it is for inflateInit2. michael@0: michael@0: inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source michael@0: stream state was inconsistent (such as zalloc or state being Z_NULL), or if michael@0: the windowBits parameter is invalid. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, michael@0: int bits, michael@0: int value)); michael@0: /* michael@0: This function inserts bits in the inflate input stream. The intent is michael@0: that this function is used to start inflating at a bit position in the michael@0: middle of a byte. The provided bits will be used before any bytes are used michael@0: from next_in. This function should only be used with raw inflate, and michael@0: should be used before the first inflate() call after inflateInit2() or michael@0: inflateReset(). bits must be less than or equal to 16, and that many of the michael@0: least significant bits of value will be inserted in the input. michael@0: michael@0: If bits is negative, then the input stream bit buffer is emptied. Then michael@0: inflatePrime() can be called again to put bits in the buffer. This is used michael@0: to clear out bits leftover after feeding inflate a block description prior michael@0: to feeding inflate codes. michael@0: michael@0: inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source michael@0: stream state was inconsistent. michael@0: */ michael@0: michael@0: ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); michael@0: /* michael@0: This function returns two values, one in the lower 16 bits of the return michael@0: value, and the other in the remaining upper bits, obtained by shifting the michael@0: return value down 16 bits. If the upper value is -1 and the lower value is michael@0: zero, then inflate() is currently decoding information outside of a block. michael@0: If the upper value is -1 and the lower value is non-zero, then inflate is in michael@0: the middle of a stored block, with the lower value equaling the number of michael@0: bytes from the input remaining to copy. If the upper value is not -1, then michael@0: it is the number of bits back from the current bit position in the input of michael@0: the code (literal or length/distance pair) currently being processed. In michael@0: that case the lower value is the number of bytes already emitted for that michael@0: code. michael@0: michael@0: A code is being processed if inflate is waiting for more input to complete michael@0: decoding of the code, or if it has completed decoding but is waiting for michael@0: more output space to write the literal or match data. michael@0: michael@0: inflateMark() is used to mark locations in the input data for random michael@0: access, which may be at bit positions, and to note those cases where the michael@0: output of a code may span boundaries of random access blocks. The current michael@0: location in the input stream can be determined from avail_in and data_type michael@0: as noted in the description for the Z_BLOCK flush parameter for inflate. michael@0: michael@0: inflateMark returns the value noted above or -1 << 16 if the provided michael@0: source stream state was inconsistent. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, michael@0: gz_headerp head)); michael@0: /* michael@0: inflateGetHeader() requests that gzip header information be stored in the michael@0: provided gz_header structure. inflateGetHeader() may be called after michael@0: inflateInit2() or inflateReset(), and before the first call of inflate(). michael@0: As inflate() processes the gzip stream, head->done is zero until the header michael@0: is completed, at which time head->done is set to one. If a zlib stream is michael@0: being decoded, then head->done is set to -1 to indicate that there will be michael@0: no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be michael@0: used to force inflate() to return immediately after header processing is michael@0: complete and before any actual data is decompressed. michael@0: michael@0: The text, time, xflags, and os fields are filled in with the gzip header michael@0: contents. hcrc is set to true if there is a header CRC. (The header CRC michael@0: was valid if done is set to one.) If extra is not Z_NULL, then extra_max michael@0: contains the maximum number of bytes to write to extra. Once done is true, michael@0: extra_len contains the actual extra field length, and extra contains the michael@0: extra field, or that field truncated if extra_max is less than extra_len. michael@0: If name is not Z_NULL, then up to name_max characters are written there, michael@0: terminated with a zero unless the length is greater than name_max. If michael@0: comment is not Z_NULL, then up to comm_max characters are written there, michael@0: terminated with a zero unless the length is greater than comm_max. When any michael@0: of extra, name, or comment are not Z_NULL and the respective field is not michael@0: present in the header, then that field is set to Z_NULL to signal its michael@0: absence. This allows the use of deflateSetHeader() with the returned michael@0: structure to duplicate the header. However if those fields are set to michael@0: allocated memory, then the application will need to save those pointers michael@0: elsewhere so that they can be eventually freed. michael@0: michael@0: If inflateGetHeader is not used, then the header information is simply michael@0: discarded. The header is always checked for validity, including the header michael@0: CRC if present. inflateReset() will reset the process to discard the header michael@0: information. The application would need to call inflateGetHeader() again to michael@0: retrieve the header from the next gzip stream. michael@0: michael@0: inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source michael@0: stream state was inconsistent. michael@0: */ michael@0: michael@0: /* michael@0: ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, michael@0: unsigned char FAR *window)); michael@0: michael@0: Initialize the internal stream state for decompression using inflateBack() michael@0: calls. The fields zalloc, zfree and opaque in strm must be initialized michael@0: before the call. If zalloc and zfree are Z_NULL, then the default library- michael@0: derived memory allocation routines are used. windowBits is the base two michael@0: logarithm of the window size, in the range 8..15. window is a caller michael@0: supplied buffer of that size. Except for special applications where it is michael@0: assured that deflate was used with small window sizes, windowBits must be 15 michael@0: and a 32K byte window must be supplied to be able to decompress general michael@0: deflate streams. michael@0: michael@0: See inflateBack() for the usage of these routines. michael@0: michael@0: inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of michael@0: the parameters are invalid, Z_MEM_ERROR if the internal state could not be michael@0: allocated, or Z_VERSION_ERROR if the version of the library does not match michael@0: the version of the header file. michael@0: */ michael@0: michael@0: typedef unsigned (*in_func) OF((void FAR *, michael@0: z_const unsigned char FAR * FAR *)); michael@0: typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); michael@0: michael@0: ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, michael@0: in_func in, void FAR *in_desc, michael@0: out_func out, void FAR *out_desc)); michael@0: /* michael@0: inflateBack() does a raw inflate with a single call using a call-back michael@0: interface for input and output. This is potentially more efficient than michael@0: inflate() for file i/o applications, in that it avoids copying between the michael@0: output and the sliding window by simply making the window itself the output michael@0: buffer. inflate() can be faster on modern CPUs when used with large michael@0: buffers. inflateBack() trusts the application to not change the output michael@0: buffer passed by the output function, at least until inflateBack() returns. michael@0: michael@0: inflateBackInit() must be called first to allocate the internal state michael@0: and to initialize the state with the user-provided window buffer. michael@0: inflateBack() may then be used multiple times to inflate a complete, raw michael@0: deflate stream with each call. inflateBackEnd() is then called to free the michael@0: allocated state. michael@0: michael@0: A raw deflate stream is one with no zlib or gzip header or trailer. michael@0: This routine would normally be used in a utility that reads zip or gzip michael@0: files and writes out uncompressed files. The utility would decode the michael@0: header and process the trailer on its own, hence this routine expects only michael@0: the raw deflate stream to decompress. This is different from the normal michael@0: behavior of inflate(), which expects either a zlib or gzip header and michael@0: trailer around the deflate stream. michael@0: michael@0: inflateBack() uses two subroutines supplied by the caller that are then michael@0: called by inflateBack() for input and output. inflateBack() calls those michael@0: routines until it reads a complete deflate stream and writes out all of the michael@0: uncompressed data, or until it encounters an error. The function's michael@0: parameters and return types are defined above in the in_func and out_func michael@0: typedefs. inflateBack() will call in(in_desc, &buf) which should return the michael@0: number of bytes of provided input, and a pointer to that input in buf. If michael@0: there is no input available, in() must return zero--buf is ignored in that michael@0: case--and inflateBack() will return a buffer error. inflateBack() will call michael@0: out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() michael@0: should return zero on success, or non-zero on failure. If out() returns michael@0: non-zero, inflateBack() will return with an error. Neither in() nor out() michael@0: are permitted to change the contents of the window provided to michael@0: inflateBackInit(), which is also the buffer that out() uses to write from. michael@0: The length written by out() will be at most the window size. Any non-zero michael@0: amount of input may be provided by in(). michael@0: michael@0: For convenience, inflateBack() can be provided input on the first call by michael@0: setting strm->next_in and strm->avail_in. If that input is exhausted, then michael@0: in() will be called. Therefore strm->next_in must be initialized before michael@0: calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called michael@0: immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in michael@0: must also be initialized, and then if strm->avail_in is not zero, input will michael@0: initially be taken from strm->next_in[0 .. strm->avail_in - 1]. michael@0: michael@0: The in_desc and out_desc parameters of inflateBack() is passed as the michael@0: first parameter of in() and out() respectively when they are called. These michael@0: descriptors can be optionally used to pass any information that the caller- michael@0: supplied in() and out() functions need to do their job. michael@0: michael@0: On return, inflateBack() will set strm->next_in and strm->avail_in to michael@0: pass back any unused input that was provided by the last in() call. The michael@0: return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR michael@0: if in() or out() returned an error, Z_DATA_ERROR if there was a format error michael@0: in the deflate stream (in which case strm->msg is set to indicate the nature michael@0: of the error), or Z_STREAM_ERROR if the stream was not properly initialized. michael@0: In the case of Z_BUF_ERROR, an input or output error can be distinguished michael@0: using strm->next_in which will be Z_NULL only if in() returned an error. If michael@0: strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning michael@0: non-zero. (in() will always be called before out(), so strm->next_in is michael@0: assured to be defined if out() returns non-zero.) Note that inflateBack() michael@0: cannot return Z_OK. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); michael@0: /* michael@0: All memory allocated by inflateBackInit() is freed. michael@0: michael@0: inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream michael@0: state was inconsistent. michael@0: */ michael@0: michael@0: ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); michael@0: /* Return flags indicating compile-time options. michael@0: michael@0: Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: michael@0: 1.0: size of uInt michael@0: 3.2: size of uLong michael@0: 5.4: size of voidpf (pointer) michael@0: 7.6: size of z_off_t michael@0: michael@0: Compiler, assembler, and debug options: michael@0: 8: DEBUG michael@0: 9: ASMV or ASMINF -- use ASM code michael@0: 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention michael@0: 11: 0 (reserved) michael@0: michael@0: One-time table building (smaller code, but not thread-safe if true): michael@0: 12: BUILDFIXED -- build static block decoding tables when needed michael@0: 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed michael@0: 14,15: 0 (reserved) michael@0: michael@0: Library content (indicates missing functionality): michael@0: 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking michael@0: deflate code when not needed) michael@0: 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect michael@0: and decode gzip streams (to avoid linking crc code) michael@0: 18-19: 0 (reserved) michael@0: michael@0: Operation variations (changes in library functionality): michael@0: 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate michael@0: 21: FASTEST -- deflate algorithm with only one, lowest compression level michael@0: 22,23: 0 (reserved) michael@0: michael@0: The sprintf variant used by gzprintf (zero is best): michael@0: 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format michael@0: 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! michael@0: 26: 0 = returns value, 1 = void -- 1 means inferred string length returned michael@0: michael@0: Remainder: michael@0: 27-31: 0 (reserved) michael@0: */ michael@0: michael@0: #ifndef Z_SOLO michael@0: michael@0: /* utility functions */ michael@0: michael@0: /* michael@0: The following utility functions are implemented on top of the basic michael@0: stream-oriented functions. To simplify the interface, some default options michael@0: are assumed (compression level and memory usage, standard memory allocation michael@0: functions). The source code of these utility functions can be modified if michael@0: you need special options. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, michael@0: const Bytef *source, uLong sourceLen)); michael@0: /* michael@0: Compresses the source buffer into the destination buffer. sourceLen is michael@0: the byte length of the source buffer. Upon entry, destLen is the total size michael@0: of the destination buffer, which must be at least the value returned by michael@0: compressBound(sourceLen). Upon exit, destLen is the actual size of the michael@0: compressed buffer. michael@0: michael@0: compress returns Z_OK if success, Z_MEM_ERROR if there was not michael@0: enough memory, Z_BUF_ERROR if there was not enough room in the output michael@0: buffer. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, michael@0: const Bytef *source, uLong sourceLen, michael@0: int level)); michael@0: /* michael@0: Compresses the source buffer into the destination buffer. The level michael@0: parameter has the same meaning as in deflateInit. sourceLen is the byte michael@0: length of the source buffer. Upon entry, destLen is the total size of the michael@0: destination buffer, which must be at least the value returned by michael@0: compressBound(sourceLen). Upon exit, destLen is the actual size of the michael@0: compressed buffer. michael@0: michael@0: compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough michael@0: memory, Z_BUF_ERROR if there was not enough room in the output buffer, michael@0: Z_STREAM_ERROR if the level parameter is invalid. michael@0: */ michael@0: michael@0: ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); michael@0: /* michael@0: compressBound() returns an upper bound on the compressed size after michael@0: compress() or compress2() on sourceLen bytes. It would be used before a michael@0: compress() or compress2() call to allocate the destination buffer. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, michael@0: const Bytef *source, uLong sourceLen)); michael@0: /* michael@0: Decompresses the source buffer into the destination buffer. sourceLen is michael@0: the byte length of the source buffer. Upon entry, destLen is the total size michael@0: of the destination buffer, which must be large enough to hold the entire michael@0: uncompressed data. (The size of the uncompressed data must have been saved michael@0: previously by the compressor and transmitted to the decompressor by some michael@0: mechanism outside the scope of this compression library.) Upon exit, destLen michael@0: is the actual size of the uncompressed buffer. michael@0: michael@0: uncompress returns Z_OK if success, Z_MEM_ERROR if there was not michael@0: enough memory, Z_BUF_ERROR if there was not enough room in the output michael@0: buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In michael@0: the case where there is not enough room, uncompress() will fill the output michael@0: buffer with the uncompressed data up to that point. michael@0: */ michael@0: michael@0: /* gzip file access functions */ michael@0: michael@0: /* michael@0: This library supports reading and writing files in gzip (.gz) format with michael@0: an interface similar to that of stdio, using the functions that start with michael@0: "gz". The gzip format is different from the zlib format. gzip is a gzip michael@0: wrapper, documented in RFC 1952, wrapped around a deflate stream. michael@0: */ michael@0: michael@0: typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ michael@0: michael@0: /* michael@0: ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); michael@0: michael@0: Opens a gzip (.gz) file for reading or writing. The mode parameter is as michael@0: in fopen ("rb" or "wb") but can also include a compression level ("wb9") or michael@0: a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only michael@0: compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F' michael@0: for fixed code compression as in "wb9F". (See the description of michael@0: deflateInit2 for more information about the strategy parameter.) 'T' will michael@0: request transparent writing or appending with no compression and not using michael@0: the gzip format. michael@0: michael@0: "a" can be used instead of "w" to request that the gzip stream that will michael@0: be written be appended to the file. "+" will result in an error, since michael@0: reading and writing to the same gzip file is not supported. The addition of michael@0: "x" when writing will create the file exclusively, which fails if the file michael@0: already exists. On systems that support it, the addition of "e" when michael@0: reading or writing will set the flag to close the file on an execve() call. michael@0: michael@0: These functions, as well as gzip, will read and decode a sequence of gzip michael@0: streams in a file. The append function of gzopen() can be used to create michael@0: such a file. (Also see gzflush() for another way to do this.) When michael@0: appending, gzopen does not test whether the file begins with a gzip stream, michael@0: nor does it look for the end of the gzip streams to begin appending. gzopen michael@0: will simply append a gzip stream to the existing file. michael@0: michael@0: gzopen can be used to read a file which is not in gzip format; in this michael@0: case gzread will directly read from the file without decompression. When michael@0: reading, this will be detected automatically by looking for the magic two- michael@0: byte gzip header. michael@0: michael@0: gzopen returns NULL if the file could not be opened, if there was michael@0: insufficient memory to allocate the gzFile state, or if an invalid mode was michael@0: specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). michael@0: errno can be checked to determine if the reason gzopen failed was that the michael@0: file could not be opened. michael@0: */ michael@0: michael@0: ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); michael@0: /* michael@0: gzdopen associates a gzFile with the file descriptor fd. File descriptors michael@0: are obtained from calls like open, dup, creat, pipe or fileno (if the file michael@0: has been previously opened with fopen). The mode parameter is as in gzopen. michael@0: michael@0: The next call of gzclose on the returned gzFile will also close the file michael@0: descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor michael@0: fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, michael@0: mode);. The duplicated descriptor should be saved to avoid a leak, since michael@0: gzdopen does not close fd if it fails. If you are using fileno() to get the michael@0: file descriptor from a FILE *, then you will have to use dup() to avoid michael@0: double-close()ing the file descriptor. Both gzclose() and fclose() will michael@0: close the associated file descriptor, so they need to have different file michael@0: descriptors. michael@0: michael@0: gzdopen returns NULL if there was insufficient memory to allocate the michael@0: gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not michael@0: provided, or '+' was provided), or if fd is -1. The file descriptor is not michael@0: used until the next gz* read, write, seek, or close operation, so gzdopen michael@0: will not detect if fd is invalid (unless fd is -1). michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size)); michael@0: /* michael@0: Set the internal buffer size used by this library's functions. The michael@0: default buffer size is 8192 bytes. This function must be called after michael@0: gzopen() or gzdopen(), and before any other calls that read or write the michael@0: file. The buffer memory allocation is always deferred to the first read or michael@0: write. Two buffers are allocated, either both of the specified size when michael@0: writing, or one of the specified size and the other twice that size when michael@0: reading. A larger buffer size of, for example, 64K or 128K bytes will michael@0: noticeably increase the speed of decompression (reading). michael@0: michael@0: The new buffer size also affects the maximum length for gzprintf(). michael@0: michael@0: gzbuffer() returns 0 on success, or -1 on failure, such as being called michael@0: too late. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); michael@0: /* michael@0: Dynamically update the compression level or strategy. See the description michael@0: of deflateInit2 for the meaning of these parameters. michael@0: michael@0: gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not michael@0: opened for writing. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); michael@0: /* michael@0: Reads the given number of uncompressed bytes from the compressed file. If michael@0: the input file is not in gzip format, gzread copies the given number of michael@0: bytes into the buffer directly from the file. michael@0: michael@0: After reaching the end of a gzip stream in the input, gzread will continue michael@0: to read, looking for another gzip stream. Any number of gzip streams may be michael@0: concatenated in the input file, and will all be decompressed by gzread(). michael@0: If something other than a gzip stream is encountered after a gzip stream, michael@0: that remaining trailing garbage is ignored (and no error is returned). michael@0: michael@0: gzread can be used to read a gzip file that is being concurrently written. michael@0: Upon reaching the end of the input, gzread will return with the available michael@0: data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then michael@0: gzclearerr can be used to clear the end of file indicator in order to permit michael@0: gzread to be tried again. Z_OK indicates that a gzip stream was completed michael@0: on the last gzread. Z_BUF_ERROR indicates that the input file ended in the michael@0: middle of a gzip stream. Note that gzread does not return -1 in the event michael@0: of an incomplete gzip stream. This error is deferred until gzclose(), which michael@0: will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip michael@0: stream. Alternatively, gzerror can be used before gzclose to detect this michael@0: case. michael@0: michael@0: gzread returns the number of uncompressed bytes actually read, less than michael@0: len for end of file, or -1 for error. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT gzwrite OF((gzFile file, michael@0: voidpc buf, unsigned len)); michael@0: /* michael@0: Writes the given number of uncompressed bytes into the compressed file. michael@0: gzwrite returns the number of uncompressed bytes written or 0 in case of michael@0: error. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...)); michael@0: /* michael@0: Converts, formats, and writes the arguments to the compressed file under michael@0: control of the format string, as in fprintf. gzprintf returns the number of michael@0: uncompressed bytes actually written, or 0 in case of error. The number of michael@0: uncompressed bytes written is limited to 8191, or one less than the buffer michael@0: size given to gzbuffer(). The caller should assure that this limit is not michael@0: exceeded. If it is exceeded, then gzprintf() will return an error (0) with michael@0: nothing written. In this case, there may also be a buffer overflow with michael@0: unpredictable consequences, which is possible only if zlib was compiled with michael@0: the insecure functions sprintf() or vsprintf() because the secure snprintf() michael@0: or vsnprintf() functions were not available. This can be determined using michael@0: zlibCompileFlags(). michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); michael@0: /* michael@0: Writes the given null-terminated string to the compressed file, excluding michael@0: the terminating null character. michael@0: michael@0: gzputs returns the number of characters written, or -1 in case of error. michael@0: */ michael@0: michael@0: ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); michael@0: /* michael@0: Reads bytes from the compressed file until len-1 characters are read, or a michael@0: newline character is read and transferred to buf, or an end-of-file michael@0: condition is encountered. If any characters are read or if len == 1, the michael@0: string is terminated with a null character. If no characters are read due michael@0: to an end-of-file or len < 1, then the buffer is left untouched. michael@0: michael@0: gzgets returns buf which is a null-terminated string, or it returns NULL michael@0: for end-of-file or in case of error. If there was an error, the contents at michael@0: buf are indeterminate. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); michael@0: /* michael@0: Writes c, converted to an unsigned char, into the compressed file. gzputc michael@0: returns the value that was written, or -1 in case of error. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); michael@0: /* michael@0: Reads one byte from the compressed file. gzgetc returns this byte or -1 michael@0: in case of end of file or error. This is implemented as a macro for speed. michael@0: As such, it does not do all of the checking the other functions do. I.e. michael@0: it does not check to see if file is NULL, nor whether the structure file michael@0: points to has been clobbered or not. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); michael@0: /* michael@0: Push one character back onto the stream to be read as the first character michael@0: on the next read. At least one character of push-back is allowed. michael@0: gzungetc() returns the character pushed, or -1 on failure. gzungetc() will michael@0: fail if c is -1, and may fail if a character has been pushed but not read michael@0: yet. If gzungetc is used immediately after gzopen or gzdopen, at least the michael@0: output buffer size of pushed characters is allowed. (See gzbuffer above.) michael@0: The pushed character will be discarded if the stream is repositioned with michael@0: gzseek() or gzrewind(). michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); michael@0: /* michael@0: Flushes all pending output into the compressed file. The parameter flush michael@0: is as in the deflate() function. The return value is the zlib error number michael@0: (see function gzerror below). gzflush is only permitted when writing. michael@0: michael@0: If the flush parameter is Z_FINISH, the remaining data is written and the michael@0: gzip stream is completed in the output. If gzwrite() is called again, a new michael@0: gzip stream will be started in the output. gzread() is able to read such michael@0: concatented gzip streams. michael@0: michael@0: gzflush should be called only when strictly necessary because it will michael@0: degrade compression if called too often. michael@0: */ michael@0: michael@0: /* michael@0: ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, michael@0: z_off_t offset, int whence)); michael@0: michael@0: Sets the starting position for the next gzread or gzwrite on the given michael@0: compressed file. The offset represents a number of bytes in the michael@0: uncompressed data stream. The whence parameter is defined as in lseek(2); michael@0: the value SEEK_END is not supported. michael@0: michael@0: If the file is opened for reading, this function is emulated but can be michael@0: extremely slow. If the file is opened for writing, only forward seeks are michael@0: supported; gzseek then compresses a sequence of zeroes up to the new michael@0: starting position. michael@0: michael@0: gzseek returns the resulting offset location as measured in bytes from michael@0: the beginning of the uncompressed stream, or -1 in case of error, in michael@0: particular if the file is opened for writing and the new starting position michael@0: would be before the current position. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); michael@0: /* michael@0: Rewinds the given file. This function is supported only for reading. michael@0: michael@0: gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) michael@0: */ michael@0: michael@0: /* michael@0: ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); michael@0: michael@0: Returns the starting position for the next gzread or gzwrite on the given michael@0: compressed file. This position represents a number of bytes in the michael@0: uncompressed data stream, and is zero when starting, even if appending or michael@0: reading a gzip stream from the middle of a file using gzdopen(). michael@0: michael@0: gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) michael@0: */ michael@0: michael@0: /* michael@0: ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); michael@0: michael@0: Returns the current offset in the file being read or written. This offset michael@0: includes the count of bytes that precede the gzip stream, for example when michael@0: appending or when using gzdopen() for reading. When reading, the offset michael@0: does not include as yet unused buffered input. This information can be used michael@0: for a progress indicator. On error, gzoffset() returns -1. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT gzeof OF((gzFile file)); michael@0: /* michael@0: Returns true (1) if the end-of-file indicator has been set while reading, michael@0: false (0) otherwise. Note that the end-of-file indicator is set only if the michael@0: read tried to go past the end of the input, but came up short. Therefore, michael@0: just like feof(), gzeof() may return false even if there is no more data to michael@0: read, in the event that the last read request was for the exact number of michael@0: bytes remaining in the input file. This will happen if the input file size michael@0: is an exact multiple of the buffer size. michael@0: michael@0: If gzeof() returns true, then the read functions will return no more data, michael@0: unless the end-of-file indicator is reset by gzclearerr() and the input file michael@0: has grown since the previous end of file was detected. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); michael@0: /* michael@0: Returns true (1) if file is being copied directly while reading, or false michael@0: (0) if file is a gzip stream being decompressed. michael@0: michael@0: If the input file is empty, gzdirect() will return true, since the input michael@0: does not contain a gzip stream. michael@0: michael@0: If gzdirect() is used immediately after gzopen() or gzdopen() it will michael@0: cause buffers to be allocated to allow reading the file to determine if it michael@0: is a gzip file. Therefore if gzbuffer() is used, it should be called before michael@0: gzdirect(). michael@0: michael@0: When writing, gzdirect() returns true (1) if transparent writing was michael@0: requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: michael@0: gzdirect() is not needed when writing. Transparent writing must be michael@0: explicitly requested, so the application already knows the answer. When michael@0: linking statically, using gzdirect() will include all of the zlib code for michael@0: gzip file reading and decompression, which may not be desired.) michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT gzclose OF((gzFile file)); michael@0: /* michael@0: Flushes all pending output if necessary, closes the compressed file and michael@0: deallocates the (de)compression state. Note that once file is closed, you michael@0: cannot call gzerror with file, since its structures have been deallocated. michael@0: gzclose must not be called more than once on the same file, just as free michael@0: must not be called more than once on the same allocation. michael@0: michael@0: gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a michael@0: file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the michael@0: last read ended in the middle of a gzip stream, or Z_OK on success. michael@0: */ michael@0: michael@0: ZEXTERN int ZEXPORT gzclose_r OF((gzFile file)); michael@0: ZEXTERN int ZEXPORT gzclose_w OF((gzFile file)); michael@0: /* michael@0: Same as gzclose(), but gzclose_r() is only for use when reading, and michael@0: gzclose_w() is only for use when writing or appending. The advantage to michael@0: using these instead of gzclose() is that they avoid linking in zlib michael@0: compression or decompression code that is not used when only reading or only michael@0: writing respectively. If gzclose() is used, then both compression and michael@0: decompression code will be included the application when linking to a static michael@0: zlib library. michael@0: */ michael@0: michael@0: ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); michael@0: /* michael@0: Returns the error message for the last error which occurred on the given michael@0: compressed file. errnum is set to zlib error number. If an error occurred michael@0: in the file system and not in the compression library, errnum is set to michael@0: Z_ERRNO and the application may consult errno to get the exact error code. michael@0: michael@0: The application must not modify the returned string. Future calls to michael@0: this function may invalidate the previously returned string. If file is michael@0: closed, then the string previously returned by gzerror will no longer be michael@0: available. michael@0: michael@0: gzerror() should be used to distinguish errors from end-of-file for those michael@0: functions above that do not distinguish those cases in their return values. michael@0: */ michael@0: michael@0: ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); michael@0: /* michael@0: Clears the error and end-of-file flags for file. This is analogous to the michael@0: clearerr() function in stdio. This is useful for continuing to read a gzip michael@0: file that is being written concurrently. michael@0: */ michael@0: michael@0: #endif /* !Z_SOLO */ michael@0: michael@0: /* checksum functions */ michael@0: michael@0: /* michael@0: These functions are not related to compression but are exported michael@0: anyway because they might be useful in applications using the compression michael@0: library. michael@0: */ michael@0: michael@0: ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); michael@0: /* michael@0: Update a running Adler-32 checksum with the bytes buf[0..len-1] and michael@0: return the updated checksum. If buf is Z_NULL, this function returns the michael@0: required initial value for the checksum. michael@0: michael@0: An Adler-32 checksum is almost as reliable as a CRC32 but can be computed michael@0: much faster. michael@0: michael@0: Usage example: michael@0: michael@0: uLong adler = adler32(0L, Z_NULL, 0); michael@0: michael@0: while (read_buffer(buffer, length) != EOF) { michael@0: adler = adler32(adler, buffer, length); michael@0: } michael@0: if (adler != original_adler) error(); michael@0: */ michael@0: michael@0: /* michael@0: ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, michael@0: z_off_t len2)); michael@0: michael@0: Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 michael@0: and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for michael@0: each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of michael@0: seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note michael@0: that the z_off_t type (like off_t) is a signed integer. If len2 is michael@0: negative, the result has no meaning or utility. michael@0: */ michael@0: michael@0: ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); michael@0: /* michael@0: Update a running CRC-32 with the bytes buf[0..len-1] and return the michael@0: updated CRC-32. If buf is Z_NULL, this function returns the required michael@0: initial value for the crc. Pre- and post-conditioning (one's complement) is michael@0: performed within this function so it shouldn't be done by the application. michael@0: michael@0: Usage example: michael@0: michael@0: uLong crc = crc32(0L, Z_NULL, 0); michael@0: michael@0: while (read_buffer(buffer, length) != EOF) { michael@0: crc = crc32(crc, buffer, length); michael@0: } michael@0: if (crc != original_crc) error(); michael@0: */ michael@0: michael@0: /* michael@0: ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); michael@0: michael@0: Combine two CRC-32 check values into one. For two sequences of bytes, michael@0: seq1 and seq2 with lengths len1 and len2, CRC-32 check values were michael@0: calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 michael@0: check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and michael@0: len2. michael@0: */ michael@0: michael@0: michael@0: /* various hacks, don't look :) */ michael@0: michael@0: /* deflateInit and inflateInit are macros to allow checking the zlib version michael@0: * and the compiler's view of z_stream: michael@0: */ michael@0: ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, michael@0: const char *version, int stream_size)); michael@0: ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, michael@0: const char *version, int stream_size)); michael@0: ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, michael@0: int windowBits, int memLevel, michael@0: int strategy, const char *version, michael@0: int stream_size)); michael@0: ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, michael@0: const char *version, int stream_size)); michael@0: ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, michael@0: unsigned char FAR *window, michael@0: const char *version, michael@0: int stream_size)); michael@0: #define deflateInit(strm, level) \ michael@0: deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) michael@0: #define inflateInit(strm) \ michael@0: inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) michael@0: #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ michael@0: deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ michael@0: (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) michael@0: #define inflateInit2(strm, windowBits) \ michael@0: inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ michael@0: (int)sizeof(z_stream)) michael@0: #define inflateBackInit(strm, windowBits, window) \ michael@0: inflateBackInit_((strm), (windowBits), (window), \ michael@0: ZLIB_VERSION, (int)sizeof(z_stream)) michael@0: michael@0: #ifndef Z_SOLO michael@0: michael@0: /* gzgetc() macro and its supporting function and exposed data structure. Note michael@0: * that the real internal state is much larger than the exposed structure. michael@0: * This abbreviated structure exposes just enough for the gzgetc() macro. The michael@0: * user should not mess with these exposed elements, since their names or michael@0: * behavior could change in the future, perhaps even capriciously. They can michael@0: * only be used by the gzgetc() macro. You have been warned. michael@0: */ michael@0: struct gzFile_s { michael@0: unsigned have; michael@0: unsigned char *next; michael@0: z_off64_t pos; michael@0: }; michael@0: ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */ michael@0: #ifdef Z_PREFIX_SET michael@0: # undef z_gzgetc michael@0: # define z_gzgetc(g) \ michael@0: ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g)) michael@0: #else michael@0: # undef gzgetc michael@0: # define gzgetc(g) \ michael@0: ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g)) michael@0: #endif michael@0: michael@0: /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or michael@0: * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if michael@0: * both are true, the application gets the *64 functions, and the regular michael@0: * functions are changed to 64 bits) -- in case these are set on systems michael@0: * without large file support, _LFS64_LARGEFILE must also be true michael@0: */ michael@0: #ifdef Z_LARGE64 michael@0: ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); michael@0: ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); michael@0: ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); michael@0: ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); michael@0: ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); michael@0: ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); michael@0: #endif michael@0: michael@0: #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64) michael@0: # ifdef Z_PREFIX_SET michael@0: # define z_gzopen z_gzopen64 michael@0: # define z_gzseek z_gzseek64 michael@0: # define z_gztell z_gztell64 michael@0: # define z_gzoffset z_gzoffset64 michael@0: # define z_adler32_combine z_adler32_combine64 michael@0: # define z_crc32_combine z_crc32_combine64 michael@0: # else michael@0: # define gzopen gzopen64 michael@0: # define gzseek gzseek64 michael@0: # define gztell gztell64 michael@0: # define gzoffset gzoffset64 michael@0: # define adler32_combine adler32_combine64 michael@0: # define crc32_combine crc32_combine64 michael@0: # endif michael@0: # ifndef Z_LARGE64 michael@0: ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); michael@0: ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int)); michael@0: ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile)); michael@0: ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile)); michael@0: ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t)); michael@0: ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t)); michael@0: # endif michael@0: #else michael@0: ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); michael@0: ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); michael@0: ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); michael@0: ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); michael@0: ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); michael@0: ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); michael@0: #endif michael@0: michael@0: #else /* Z_SOLO */ michael@0: michael@0: ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); michael@0: ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); michael@0: michael@0: #endif /* !Z_SOLO */ michael@0: michael@0: /* hack for buggy compilers */ michael@0: #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) michael@0: struct internal_state {int dummy;}; michael@0: #endif michael@0: michael@0: /* undocumented functions */ michael@0: ZEXTERN const char * ZEXPORT zError OF((int)); michael@0: ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); michael@0: ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void)); michael@0: ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); michael@0: ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp)); michael@0: ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp)); michael@0: #if defined(_WIN32) && !defined(Z_SOLO) michael@0: ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path, michael@0: const char *mode)); michael@0: #endif michael@0: #if defined(STDC) || defined(Z_HAVE_STDARG_H) michael@0: # ifndef Z_SOLO michael@0: ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file, michael@0: const char *format, michael@0: va_list va)); michael@0: # endif michael@0: #endif michael@0: michael@0: #ifdef __cplusplus michael@0: } michael@0: #endif michael@0: michael@0: #endif /* ZLIB_H */