Chris@4: /* zlib.h -- interface of the 'zlib' general purpose compression library Chris@4: version 1.2.7, May 2nd, 2012 Chris@4: Chris@4: Copyright (C) 1995-2012 Jean-loup Gailly and Mark Adler Chris@4: Chris@4: This software is provided 'as-is', without any express or implied Chris@4: warranty. In no event will the authors be held liable for any damages Chris@4: arising from the use of this software. Chris@4: Chris@4: Permission is granted to anyone to use this software for any purpose, Chris@4: including commercial applications, and to alter it and redistribute it Chris@4: freely, subject to the following restrictions: Chris@4: Chris@4: 1. The origin of this software must not be misrepresented; you must not Chris@4: claim that you wrote the original software. If you use this software Chris@4: in a product, an acknowledgment in the product documentation would be Chris@4: appreciated but is not required. Chris@4: 2. Altered source versions must be plainly marked as such, and must not be Chris@4: misrepresented as being the original software. Chris@4: 3. This notice may not be removed or altered from any source distribution. Chris@4: Chris@4: Jean-loup Gailly Mark Adler Chris@4: jloup@gzip.org madler@alumni.caltech.edu Chris@4: Chris@4: Chris@4: The data format used by the zlib library is described by RFCs (Request for Chris@4: Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950 Chris@4: (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format). Chris@4: */ Chris@4: Chris@4: #ifndef ZLIB_H Chris@4: #define ZLIB_H Chris@4: Chris@4: #include "zconf.h" Chris@4: Chris@4: #ifdef __cplusplus Chris@4: extern "C" { Chris@4: #endif Chris@4: Chris@4: #define ZLIB_VERSION "1.2.7" Chris@4: #define ZLIB_VERNUM 0x1270 Chris@4: #define ZLIB_VER_MAJOR 1 Chris@4: #define ZLIB_VER_MINOR 2 Chris@4: #define ZLIB_VER_REVISION 7 Chris@4: #define ZLIB_VER_SUBREVISION 0 Chris@4: Chris@4: /* Chris@4: The 'zlib' compression library provides in-memory compression and Chris@4: decompression functions, including integrity checks of the uncompressed data. Chris@4: This version of the library supports only one compression method (deflation) Chris@4: but other algorithms will be added later and will have the same stream Chris@4: interface. Chris@4: Chris@4: Compression can be done in a single step if the buffers are large enough, Chris@4: or can be done by repeated calls of the compression function. In the latter Chris@4: case, the application must provide more input and/or consume the output Chris@4: (providing more output space) before each call. Chris@4: Chris@4: The compressed data format used by default by the in-memory functions is Chris@4: the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped Chris@4: around a deflate stream, which is itself documented in RFC 1951. Chris@4: Chris@4: The library also supports reading and writing files in gzip (.gz) format Chris@4: with an interface similar to that of stdio using the functions that start Chris@4: with "gz". The gzip format is different from the zlib format. gzip is a Chris@4: gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. Chris@4: Chris@4: This library can optionally read and write gzip streams in memory as well. Chris@4: Chris@4: The zlib format was designed to be compact and fast for use in memory Chris@4: and on communications channels. The gzip format was designed for single- Chris@4: file compression on file systems, has a larger header than zlib to maintain Chris@4: directory information, and uses a different, slower check method than zlib. Chris@4: Chris@4: The library does not install any signal handler. The decoder checks Chris@4: the consistency of the compressed data, so the library should never crash Chris@4: even in case of corrupted input. Chris@4: */ Chris@4: Chris@4: typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); Chris@4: typedef void (*free_func) OF((voidpf opaque, voidpf address)); Chris@4: Chris@4: struct internal_state; Chris@4: Chris@4: typedef struct z_stream_s { Chris@4: z_const Bytef *next_in; /* next input byte */ Chris@4: uInt avail_in; /* number of bytes available at next_in */ Chris@4: uLong total_in; /* total number of input bytes read so far */ Chris@4: Chris@4: Bytef *next_out; /* next output byte should be put there */ Chris@4: uInt avail_out; /* remaining free space at next_out */ Chris@4: uLong total_out; /* total number of bytes output so far */ Chris@4: Chris@4: z_const char *msg; /* last error message, NULL if no error */ Chris@4: struct internal_state FAR *state; /* not visible by applications */ Chris@4: Chris@4: alloc_func zalloc; /* used to allocate the internal state */ Chris@4: free_func zfree; /* used to free the internal state */ Chris@4: voidpf opaque; /* private data object passed to zalloc and zfree */ Chris@4: Chris@4: int data_type; /* best guess about the data type: binary or text */ Chris@4: uLong adler; /* adler32 value of the uncompressed data */ Chris@4: uLong reserved; /* reserved for future use */ Chris@4: } z_stream; Chris@4: Chris@4: typedef z_stream FAR *z_streamp; Chris@4: Chris@4: /* Chris@4: gzip header information passed to and from zlib routines. See RFC 1952 Chris@4: for more details on the meanings of these fields. Chris@4: */ Chris@4: typedef struct gz_header_s { Chris@4: int text; /* true if compressed data believed to be text */ Chris@4: uLong time; /* modification time */ Chris@4: int xflags; /* extra flags (not used when writing a gzip file) */ Chris@4: int os; /* operating system */ Chris@4: Bytef *extra; /* pointer to extra field or Z_NULL if none */ Chris@4: uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ Chris@4: uInt extra_max; /* space at extra (only when reading header) */ Chris@4: Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ Chris@4: uInt name_max; /* space at name (only when reading header) */ Chris@4: Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ Chris@4: uInt comm_max; /* space at comment (only when reading header) */ Chris@4: int hcrc; /* true if there was or will be a header crc */ Chris@4: int done; /* true when done reading gzip header (not used Chris@4: when writing a gzip file) */ Chris@4: } gz_header; Chris@4: Chris@4: typedef gz_header FAR *gz_headerp; Chris@4: Chris@4: /* Chris@4: The application must update next_in and avail_in when avail_in has dropped Chris@4: to zero. It must update next_out and avail_out when avail_out has dropped Chris@4: to zero. The application must initialize zalloc, zfree and opaque before Chris@4: calling the init function. All other fields are set by the compression Chris@4: library and must not be updated by the application. Chris@4: Chris@4: The opaque value provided by the application will be passed as the first Chris@4: parameter for calls of zalloc and zfree. This can be useful for custom Chris@4: memory management. The compression library attaches no meaning to the Chris@4: opaque value. Chris@4: Chris@4: zalloc must return Z_NULL if there is not enough memory for the object. Chris@4: If zlib is used in a multi-threaded application, zalloc and zfree must be Chris@4: thread safe. Chris@4: Chris@4: On 16-bit systems, the functions zalloc and zfree must be able to allocate Chris@4: exactly 65536 bytes, but will not be required to allocate more than this if Chris@4: the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers Chris@4: returned by zalloc for objects of exactly 65536 bytes *must* have their Chris@4: offset normalized to zero. The default allocation function provided by this Chris@4: library ensures this (see zutil.c). To reduce memory requirements and avoid Chris@4: any allocation of 64K objects, at the expense of compression ratio, compile Chris@4: the library with -DMAX_WBITS=14 (see zconf.h). Chris@4: Chris@4: The fields total_in and total_out can be used for statistics or progress Chris@4: reports. After compression, total_in holds the total size of the Chris@4: uncompressed data and may be saved for use in the decompressor (particularly Chris@4: if the decompressor wants to decompress everything in a single step). Chris@4: */ Chris@4: Chris@4: /* constants */ Chris@4: Chris@4: #define Z_NO_FLUSH 0 Chris@4: #define Z_PARTIAL_FLUSH 1 Chris@4: #define Z_SYNC_FLUSH 2 Chris@4: #define Z_FULL_FLUSH 3 Chris@4: #define Z_FINISH 4 Chris@4: #define Z_BLOCK 5 Chris@4: #define Z_TREES 6 Chris@4: /* Allowed flush values; see deflate() and inflate() below for details */ Chris@4: Chris@4: #define Z_OK 0 Chris@4: #define Z_STREAM_END 1 Chris@4: #define Z_NEED_DICT 2 Chris@4: #define Z_ERRNO (-1) Chris@4: #define Z_STREAM_ERROR (-2) Chris@4: #define Z_DATA_ERROR (-3) Chris@4: #define Z_MEM_ERROR (-4) Chris@4: #define Z_BUF_ERROR (-5) Chris@4: #define Z_VERSION_ERROR (-6) Chris@4: /* Return codes for the compression/decompression functions. Negative values Chris@4: * are errors, positive values are used for special but normal events. Chris@4: */ Chris@4: Chris@4: #define Z_NO_COMPRESSION 0 Chris@4: #define Z_BEST_SPEED 1 Chris@4: #define Z_BEST_COMPRESSION 9 Chris@4: #define Z_DEFAULT_COMPRESSION (-1) Chris@4: /* compression levels */ Chris@4: Chris@4: #define Z_FILTERED 1 Chris@4: #define Z_HUFFMAN_ONLY 2 Chris@4: #define Z_RLE 3 Chris@4: #define Z_FIXED 4 Chris@4: #define Z_DEFAULT_STRATEGY 0 Chris@4: /* compression strategy; see deflateInit2() below for details */ Chris@4: Chris@4: #define Z_BINARY 0 Chris@4: #define Z_TEXT 1 Chris@4: #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ Chris@4: #define Z_UNKNOWN 2 Chris@4: /* Possible values of the data_type field (though see inflate()) */ Chris@4: Chris@4: #define Z_DEFLATED 8 Chris@4: /* The deflate compression method (the only one supported in this version) */ Chris@4: Chris@4: #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ Chris@4: Chris@4: #define zlib_version zlibVersion() Chris@4: /* for compatibility with versions < 1.0.2 */ Chris@4: Chris@4: Chris@4: /* basic functions */ Chris@4: Chris@4: ZEXTERN const char * ZEXPORT zlibVersion OF((void)); Chris@4: /* The application can compare zlibVersion and ZLIB_VERSION for consistency. Chris@4: If the first character differs, the library code actually used is not Chris@4: compatible with the zlib.h header file used by the application. This check Chris@4: is automatically made by deflateInit and inflateInit. Chris@4: */ Chris@4: Chris@4: /* Chris@4: ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); Chris@4: Chris@4: Initializes the internal stream state for compression. The fields Chris@4: zalloc, zfree and opaque must be initialized before by the caller. If Chris@4: zalloc and zfree are set to Z_NULL, deflateInit updates them to use default Chris@4: allocation functions. Chris@4: Chris@4: The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: Chris@4: 1 gives best speed, 9 gives best compression, 0 gives no compression at all Chris@4: (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION Chris@4: requests a default compromise between speed and compression (currently Chris@4: equivalent to level 6). Chris@4: Chris@4: deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough Chris@4: memory, Z_STREAM_ERROR if level is not a valid compression level, or Chris@4: Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible Chris@4: with the version assumed by the caller (ZLIB_VERSION). msg is set to null Chris@4: if there is no error message. deflateInit does not perform any compression: Chris@4: this will be done by deflate(). Chris@4: */ Chris@4: Chris@4: Chris@4: ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); Chris@4: /* Chris@4: deflate compresses as much data as possible, and stops when the input Chris@4: buffer becomes empty or the output buffer becomes full. It may introduce Chris@4: some output latency (reading input without producing any output) except when Chris@4: forced to flush. Chris@4: Chris@4: The detailed semantics are as follows. deflate performs one or both of the Chris@4: following actions: Chris@4: Chris@4: - Compress more input starting at next_in and update next_in and avail_in Chris@4: accordingly. If not all input can be processed (because there is not Chris@4: enough room in the output buffer), next_in and avail_in are updated and Chris@4: processing will resume at this point for the next call of deflate(). Chris@4: Chris@4: - Provide more output starting at next_out and update next_out and avail_out Chris@4: accordingly. This action is forced if the parameter flush is non zero. Chris@4: Forcing flush frequently degrades the compression ratio, so this parameter Chris@4: should be set only when necessary (in interactive applications). Some Chris@4: output may be provided even if flush is not set. Chris@4: Chris@4: Before the call of deflate(), the application should ensure that at least Chris@4: one of the actions is possible, by providing more input and/or consuming more Chris@4: output, and updating avail_in or avail_out accordingly; avail_out should Chris@4: never be zero before the call. The application can consume the compressed Chris@4: output when it wants, for example when the output buffer is full (avail_out Chris@4: == 0), or after each call of deflate(). If deflate returns Z_OK and with Chris@4: zero avail_out, it must be called again after making room in the output Chris@4: buffer because there might be more output pending. Chris@4: Chris@4: Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to Chris@4: decide how much data to accumulate before producing output, in order to Chris@4: maximize compression. Chris@4: Chris@4: If the parameter flush is set to Z_SYNC_FLUSH, all pending output is Chris@4: flushed to the output buffer and the output is aligned on a byte boundary, so Chris@4: that the decompressor can get all input data available so far. (In Chris@4: particular avail_in is zero after the call if enough output space has been Chris@4: provided before the call.) Flushing may degrade compression for some Chris@4: compression algorithms and so it should be used only when necessary. This Chris@4: completes the current deflate block and follows it with an empty stored block Chris@4: that is three bits plus filler bits to the next byte, followed by four bytes Chris@4: (00 00 ff ff). Chris@4: Chris@4: If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the Chris@4: output buffer, but the output is not aligned to a byte boundary. All of the Chris@4: input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. Chris@4: This completes the current deflate block and follows it with an empty fixed Chris@4: codes block that is 10 bits long. This assures that enough bytes are output Chris@4: in order for the decompressor to finish the block before the empty fixed code Chris@4: block. Chris@4: Chris@4: If flush is set to Z_BLOCK, a deflate block is completed and emitted, as Chris@4: for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to Chris@4: seven bits of the current block are held to be written as the next byte after Chris@4: the next deflate block is completed. In this case, the decompressor may not Chris@4: be provided enough bits at this point in order to complete decompression of Chris@4: the data provided so far to the compressor. It may need to wait for the next Chris@4: block to be emitted. This is for advanced applications that need to control Chris@4: the emission of deflate blocks. Chris@4: Chris@4: If flush is set to Z_FULL_FLUSH, all output is flushed as with Chris@4: Z_SYNC_FLUSH, and the compression state is reset so that decompression can Chris@4: restart from this point if previous compressed data has been damaged or if Chris@4: random access is desired. Using Z_FULL_FLUSH too often can seriously degrade Chris@4: compression. Chris@4: Chris@4: If deflate returns with avail_out == 0, this function must be called again Chris@4: with the same value of the flush parameter and more output space (updated Chris@4: avail_out), until the flush is complete (deflate returns with non-zero Chris@4: avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that Chris@4: avail_out is greater than six to avoid repeated flush markers due to Chris@4: avail_out == 0 on return. Chris@4: Chris@4: If the parameter flush is set to Z_FINISH, pending input is processed, Chris@4: pending output is flushed and deflate returns with Z_STREAM_END if there was Chris@4: enough output space; if deflate returns with Z_OK, this function must be Chris@4: called again with Z_FINISH and more output space (updated avail_out) but no Chris@4: more input data, until it returns with Z_STREAM_END or an error. After Chris@4: deflate has returned Z_STREAM_END, the only possible operations on the stream Chris@4: are deflateReset or deflateEnd. Chris@4: Chris@4: Z_FINISH can be used immediately after deflateInit if all the compression Chris@4: is to be done in a single step. In this case, avail_out must be at least the Chris@4: value returned by deflateBound (see below). Then deflate is guaranteed to Chris@4: return Z_STREAM_END. If not enough output space is provided, deflate will Chris@4: not return Z_STREAM_END, and it must be called again as described above. Chris@4: Chris@4: deflate() sets strm->adler to the adler32 checksum of all input read Chris@4: so far (that is, total_in bytes). Chris@4: Chris@4: deflate() may update strm->data_type if it can make a good guess about Chris@4: the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered Chris@4: binary. This field is only for information purposes and does not affect the Chris@4: compression algorithm in any manner. Chris@4: Chris@4: deflate() returns Z_OK if some progress has been made (more input Chris@4: processed or more output produced), Z_STREAM_END if all input has been Chris@4: consumed and all output has been produced (only when flush is set to Chris@4: Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example Chris@4: if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible Chris@4: (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not Chris@4: fatal, and deflate() can be called again with more input and more output Chris@4: space to continue compressing. Chris@4: */ Chris@4: Chris@4: Chris@4: ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); Chris@4: /* Chris@4: All dynamically allocated data structures for this stream are freed. Chris@4: This function discards any unprocessed input and does not flush any pending Chris@4: output. Chris@4: Chris@4: deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the Chris@4: stream state was inconsistent, Z_DATA_ERROR if the stream was freed Chris@4: prematurely (some input or output was discarded). In the error case, msg Chris@4: may be set but then points to a static string (which must not be Chris@4: deallocated). Chris@4: */ Chris@4: Chris@4: Chris@4: /* Chris@4: ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); Chris@4: Chris@4: Initializes the internal stream state for decompression. The fields Chris@4: next_in, avail_in, zalloc, zfree and opaque must be initialized before by Chris@4: the caller. If next_in is not Z_NULL and avail_in is large enough (the Chris@4: exact value depends on the compression method), inflateInit determines the Chris@4: compression method from the zlib header and allocates all data structures Chris@4: accordingly; otherwise the allocation will be deferred to the first call of Chris@4: inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to Chris@4: use default allocation functions. Chris@4: Chris@4: inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough Chris@4: memory, Z_VERSION_ERROR if the zlib library version is incompatible with the Chris@4: version assumed by the caller, or Z_STREAM_ERROR if the parameters are Chris@4: invalid, such as a null pointer to the structure. msg is set to null if Chris@4: there is no error message. inflateInit does not perform any decompression Chris@4: apart from possibly reading the zlib header if present: actual decompression Chris@4: will be done by inflate(). (So next_in and avail_in may be modified, but Chris@4: next_out and avail_out are unused and unchanged.) The current implementation Chris@4: of inflateInit() does not process any header information -- that is deferred Chris@4: until inflate() is called. Chris@4: */ Chris@4: Chris@4: Chris@4: ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); Chris@4: /* Chris@4: inflate decompresses as much data as possible, and stops when the input Chris@4: buffer becomes empty or the output buffer becomes full. It may introduce Chris@4: some output latency (reading input without producing any output) except when Chris@4: forced to flush. Chris@4: Chris@4: The detailed semantics are as follows. inflate performs one or both of the Chris@4: following actions: Chris@4: Chris@4: - Decompress more input starting at next_in and update next_in and avail_in Chris@4: accordingly. If not all input can be processed (because there is not Chris@4: enough room in the output buffer), next_in is updated and processing will Chris@4: resume at this point for the next call of inflate(). Chris@4: Chris@4: - Provide more output starting at next_out and update next_out and avail_out Chris@4: accordingly. inflate() provides as much output as possible, until there is Chris@4: no more input data or no more space in the output buffer (see below about Chris@4: the flush parameter). Chris@4: Chris@4: Before the call of inflate(), the application should ensure that at least Chris@4: one of the actions is possible, by providing more input and/or consuming more Chris@4: output, and updating the next_* and avail_* values accordingly. The Chris@4: application can consume the uncompressed output when it wants, for example Chris@4: when the output buffer is full (avail_out == 0), or after each call of Chris@4: inflate(). If inflate returns Z_OK and with zero avail_out, it must be Chris@4: called again after making room in the output buffer because there might be Chris@4: more output pending. Chris@4: Chris@4: The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, Chris@4: Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much Chris@4: output as possible to the output buffer. Z_BLOCK requests that inflate() Chris@4: stop if and when it gets to the next deflate block boundary. When decoding Chris@4: the zlib or gzip format, this will cause inflate() to return immediately Chris@4: after the header and before the first block. When doing a raw inflate, Chris@4: inflate() will go ahead and process the first block, and will return when it Chris@4: gets to the end of that block, or when it runs out of data. Chris@4: Chris@4: The Z_BLOCK option assists in appending to or combining deflate streams. Chris@4: Also to assist in this, on return inflate() will set strm->data_type to the Chris@4: number of unused bits in the last byte taken from strm->next_in, plus 64 if Chris@4: inflate() is currently decoding the last block in the deflate stream, plus Chris@4: 128 if inflate() returned immediately after decoding an end-of-block code or Chris@4: decoding the complete header up to just before the first byte of the deflate Chris@4: stream. The end-of-block will not be indicated until all of the uncompressed Chris@4: data from that block has been written to strm->next_out. The number of Chris@4: unused bits may in general be greater than seven, except when bit 7 of Chris@4: data_type is set, in which case the number of unused bits will be less than Chris@4: eight. data_type is set as noted here every time inflate() returns for all Chris@4: flush options, and so can be used to determine the amount of currently Chris@4: consumed input in bits. Chris@4: Chris@4: The Z_TREES option behaves as Z_BLOCK does, but it also returns when the Chris@4: end of each deflate block header is reached, before any actual data in that Chris@4: block is decoded. This allows the caller to determine the length of the Chris@4: deflate block header for later use in random access within a deflate block. Chris@4: 256 is added to the value of strm->data_type when inflate() returns Chris@4: immediately after reaching the end of the deflate block header. Chris@4: Chris@4: inflate() should normally be called until it returns Z_STREAM_END or an Chris@4: error. However if all decompression is to be performed in a single step (a Chris@4: single call of inflate), the parameter flush should be set to Z_FINISH. In Chris@4: this case all pending input is processed and all pending output is flushed; Chris@4: avail_out must be large enough to hold all of the uncompressed data for the Chris@4: operation to complete. (The size of the uncompressed data may have been Chris@4: saved by the compressor for this purpose.) The use of Z_FINISH is not Chris@4: required to perform an inflation in one step. However it may be used to Chris@4: inform inflate that a faster approach can be used for the single inflate() Chris@4: call. Z_FINISH also informs inflate to not maintain a sliding window if the Chris@4: stream completes, which reduces inflate's memory footprint. If the stream Chris@4: does not complete, either because not all of the stream is provided or not Chris@4: enough output space is provided, then a sliding window will be allocated and Chris@4: inflate() can be called again to continue the operation as if Z_NO_FLUSH had Chris@4: been used. Chris@4: Chris@4: In this implementation, inflate() always flushes as much output as Chris@4: possible to the output buffer, and always uses the faster approach on the Chris@4: first call. So the effects of the flush parameter in this implementation are Chris@4: on the return value of inflate() as noted below, when inflate() returns early Chris@4: when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of Chris@4: memory for a sliding window when Z_FINISH is used. Chris@4: Chris@4: If a preset dictionary is needed after this call (see inflateSetDictionary Chris@4: below), inflate sets strm->adler to the Adler-32 checksum of the dictionary Chris@4: chosen by the compressor and returns Z_NEED_DICT; otherwise it sets Chris@4: strm->adler to the Adler-32 checksum of all output produced so far (that is, Chris@4: total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described Chris@4: below. At the end of the stream, inflate() checks that its computed adler32 Chris@4: checksum is equal to that saved by the compressor and returns Z_STREAM_END Chris@4: only if the checksum is correct. Chris@4: Chris@4: inflate() can decompress and check either zlib-wrapped or gzip-wrapped Chris@4: deflate data. The header type is detected automatically, if requested when Chris@4: initializing with inflateInit2(). Any information contained in the gzip Chris@4: header is not retained, so applications that need that information should Chris@4: instead use raw inflate, see inflateInit2() below, or inflateBack() and Chris@4: perform their own processing of the gzip header and trailer. When processing Chris@4: gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output Chris@4: producted so far. The CRC-32 is checked against the gzip trailer. Chris@4: Chris@4: inflate() returns Z_OK if some progress has been made (more input processed Chris@4: or more output produced), Z_STREAM_END if the end of the compressed data has Chris@4: been reached and all uncompressed output has been produced, Z_NEED_DICT if a Chris@4: preset dictionary is needed at this point, Z_DATA_ERROR if the input data was Chris@4: corrupted (input stream not conforming to the zlib format or incorrect check Chris@4: value), Z_STREAM_ERROR if the stream structure was inconsistent (for example Chris@4: next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory, Chris@4: Z_BUF_ERROR if no progress is possible or if there was not enough room in the Chris@4: output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and Chris@4: inflate() can be called again with more input and more output space to Chris@4: continue decompressing. If Z_DATA_ERROR is returned, the application may Chris@4: then call inflateSync() to look for a good compression block if a partial Chris@4: recovery of the data is desired. Chris@4: */ Chris@4: Chris@4: Chris@4: ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); Chris@4: /* Chris@4: All dynamically allocated data structures for this stream are freed. Chris@4: This function discards any unprocessed input and does not flush any pending Chris@4: output. Chris@4: Chris@4: inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state Chris@4: was inconsistent. In the error case, msg may be set but then points to a Chris@4: static string (which must not be deallocated). Chris@4: */ Chris@4: Chris@4: Chris@4: /* Advanced functions */ Chris@4: Chris@4: /* Chris@4: The following functions are needed only in some special applications. Chris@4: */ Chris@4: Chris@4: /* Chris@4: ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, Chris@4: int level, Chris@4: int method, Chris@4: int windowBits, Chris@4: int memLevel, Chris@4: int strategy)); Chris@4: Chris@4: This is another version of deflateInit with more compression options. The Chris@4: fields next_in, zalloc, zfree and opaque must be initialized before by the Chris@4: caller. Chris@4: Chris@4: The method parameter is the compression method. It must be Z_DEFLATED in Chris@4: this version of the library. Chris@4: Chris@4: The windowBits parameter is the base two logarithm of the window size Chris@4: (the size of the history buffer). It should be in the range 8..15 for this Chris@4: version of the library. Larger values of this parameter result in better Chris@4: compression at the expense of memory usage. The default value is 15 if Chris@4: deflateInit is used instead. Chris@4: Chris@4: windowBits can also be -8..-15 for raw deflate. In this case, -windowBits Chris@4: determines the window size. deflate() will then generate raw deflate data Chris@4: with no zlib header or trailer, and will not compute an adler32 check value. Chris@4: Chris@4: windowBits can also be greater than 15 for optional gzip encoding. Add Chris@4: 16 to windowBits to write a simple gzip header and trailer around the Chris@4: compressed data instead of a zlib wrapper. The gzip header will have no Chris@4: file name, no extra data, no comment, no modification time (set to zero), no Chris@4: header crc, and the operating system will be set to 255 (unknown). If a Chris@4: gzip stream is being written, strm->adler is a crc32 instead of an adler32. Chris@4: Chris@4: The memLevel parameter specifies how much memory should be allocated Chris@4: for the internal compression state. memLevel=1 uses minimum memory but is Chris@4: slow and reduces compression ratio; memLevel=9 uses maximum memory for Chris@4: optimal speed. The default value is 8. See zconf.h for total memory usage Chris@4: as a function of windowBits and memLevel. Chris@4: Chris@4: The strategy parameter is used to tune the compression algorithm. Use the Chris@4: value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a Chris@4: filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no Chris@4: string match), or Z_RLE to limit match distances to one (run-length Chris@4: encoding). Filtered data consists mostly of small values with a somewhat Chris@4: random distribution. In this case, the compression algorithm is tuned to Chris@4: compress them better. The effect of Z_FILTERED is to force more Huffman Chris@4: coding and less string matching; it is somewhat intermediate between Chris@4: Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as Chris@4: fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The Chris@4: strategy parameter only affects the compression ratio but not the Chris@4: correctness of the compressed output even if it is not set appropriately. Chris@4: Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler Chris@4: decoder for special applications. Chris@4: Chris@4: deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough Chris@4: memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid Chris@4: method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is Chris@4: incompatible with the version assumed by the caller (ZLIB_VERSION). msg is Chris@4: set to null if there is no error message. deflateInit2 does not perform any Chris@4: compression: this will be done by deflate(). Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, Chris@4: const Bytef *dictionary, Chris@4: uInt dictLength)); Chris@4: /* Chris@4: Initializes the compression dictionary from the given byte sequence Chris@4: without producing any compressed output. When using the zlib format, this Chris@4: function must be called immediately after deflateInit, deflateInit2 or Chris@4: deflateReset, and before any call of deflate. When doing raw deflate, this Chris@4: function must be called either before any call of deflate, or immediately Chris@4: after the completion of a deflate block, i.e. after all input has been Chris@4: consumed and all output has been delivered when using any of the flush Chris@4: options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The Chris@4: compressor and decompressor must use exactly the same dictionary (see Chris@4: inflateSetDictionary). Chris@4: Chris@4: The dictionary should consist of strings (byte sequences) that are likely Chris@4: to be encountered later in the data to be compressed, with the most commonly Chris@4: used strings preferably put towards the end of the dictionary. Using a Chris@4: dictionary is most useful when the data to be compressed is short and can be Chris@4: predicted with good accuracy; the data can then be compressed better than Chris@4: with the default empty dictionary. Chris@4: Chris@4: Depending on the size of the compression data structures selected by Chris@4: deflateInit or deflateInit2, a part of the dictionary may in effect be Chris@4: discarded, for example if the dictionary is larger than the window size Chris@4: provided in deflateInit or deflateInit2. Thus the strings most likely to be Chris@4: useful should be put at the end of the dictionary, not at the front. In Chris@4: addition, the current implementation of deflate will use at most the window Chris@4: size minus 262 bytes of the provided dictionary. Chris@4: Chris@4: Upon return of this function, strm->adler is set to the adler32 value Chris@4: of the dictionary; the decompressor may later use this value to determine Chris@4: which dictionary has been used by the compressor. (The adler32 value Chris@4: applies to the whole dictionary even if only a subset of the dictionary is Chris@4: actually used by the compressor.) If a raw deflate was requested, then the Chris@4: adler32 value is not computed and strm->adler is not set. Chris@4: Chris@4: deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a Chris@4: parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is Chris@4: inconsistent (for example if deflate has already been called for this stream Chris@4: or if not at a block boundary for raw deflate). deflateSetDictionary does Chris@4: not perform any compression: this will be done by deflate(). Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, Chris@4: z_streamp source)); Chris@4: /* Chris@4: Sets the destination stream as a complete copy of the source stream. Chris@4: Chris@4: This function can be useful when several compression strategies will be Chris@4: tried, for example when there are several ways of pre-processing the input Chris@4: data with a filter. The streams that will be discarded should then be freed Chris@4: by calling deflateEnd. Note that deflateCopy duplicates the internal Chris@4: compression state which can be quite large, so this strategy is slow and can Chris@4: consume lots of memory. Chris@4: Chris@4: deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not Chris@4: enough memory, Z_STREAM_ERROR if the source stream state was inconsistent Chris@4: (such as zalloc being Z_NULL). msg is left unchanged in both source and Chris@4: destination. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); Chris@4: /* Chris@4: This function is equivalent to deflateEnd followed by deflateInit, Chris@4: but does not free and reallocate all the internal compression state. The Chris@4: stream will keep the same compression level and any other attributes that Chris@4: may have been set by deflateInit2. Chris@4: Chris@4: deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source Chris@4: stream state was inconsistent (such as zalloc or state being Z_NULL). Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, Chris@4: int level, Chris@4: int strategy)); Chris@4: /* Chris@4: Dynamically update the compression level and compression strategy. The Chris@4: interpretation of level and strategy is as in deflateInit2. This can be Chris@4: used to switch between compression and straight copy of the input data, or Chris@4: to switch to a different kind of input data requiring a different strategy. Chris@4: If the compression level is changed, the input available so far is Chris@4: compressed with the old level (and may be flushed); the new level will take Chris@4: effect only at the next call of deflate(). Chris@4: Chris@4: Before the call of deflateParams, the stream state must be set as for Chris@4: a call of deflate(), since the currently available input may have to be Chris@4: compressed and flushed. In particular, strm->avail_out must be non-zero. Chris@4: Chris@4: deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source Chris@4: stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if Chris@4: strm->avail_out was zero. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, Chris@4: int good_length, Chris@4: int max_lazy, Chris@4: int nice_length, Chris@4: int max_chain)); Chris@4: /* Chris@4: Fine tune deflate's internal compression parameters. This should only be Chris@4: used by someone who understands the algorithm used by zlib's deflate for Chris@4: searching for the best matching string, and even then only by the most Chris@4: fanatic optimizer trying to squeeze out the last compressed bit for their Chris@4: specific input data. Read the deflate.c source code for the meaning of the Chris@4: max_lazy, good_length, nice_length, and max_chain parameters. Chris@4: Chris@4: deflateTune() can be called after deflateInit() or deflateInit2(), and Chris@4: returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. Chris@4: */ Chris@4: Chris@4: ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, Chris@4: uLong sourceLen)); Chris@4: /* Chris@4: deflateBound() returns an upper bound on the compressed size after Chris@4: deflation of sourceLen bytes. It must be called after deflateInit() or Chris@4: deflateInit2(), and after deflateSetHeader(), if used. This would be used Chris@4: to allocate an output buffer for deflation in a single pass, and so would be Chris@4: called before deflate(). If that first deflate() call is provided the Chris@4: sourceLen input bytes, an output buffer allocated to the size returned by Chris@4: deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed Chris@4: to return Z_STREAM_END. Note that it is possible for the compressed size to Chris@4: be larger than the value returned by deflateBound() if flush options other Chris@4: than Z_FINISH or Z_NO_FLUSH are used. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm, Chris@4: unsigned *pending, Chris@4: int *bits)); Chris@4: /* Chris@4: deflatePending() returns the number of bytes and bits of output that have Chris@4: been generated, but not yet provided in the available output. The bytes not Chris@4: provided would be due to the available output space having being consumed. Chris@4: The number of bits of output not provided are between 0 and 7, where they Chris@4: await more bits to join them in order to fill out a full byte. If pending Chris@4: or bits are Z_NULL, then those values are not set. Chris@4: Chris@4: deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source Chris@4: stream state was inconsistent. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, Chris@4: int bits, Chris@4: int value)); Chris@4: /* Chris@4: deflatePrime() inserts bits in the deflate output stream. The intent Chris@4: is that this function is used to start off the deflate output with the bits Chris@4: leftover from a previous deflate stream when appending to it. As such, this Chris@4: function can only be used for raw deflate, and must be used before the first Chris@4: deflate() call after a deflateInit2() or deflateReset(). bits must be less Chris@4: than or equal to 16, and that many of the least significant bits of value Chris@4: will be inserted in the output. Chris@4: Chris@4: deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough Chris@4: room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the Chris@4: source stream state was inconsistent. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, Chris@4: gz_headerp head)); Chris@4: /* Chris@4: deflateSetHeader() provides gzip header information for when a gzip Chris@4: stream is requested by deflateInit2(). deflateSetHeader() may be called Chris@4: after deflateInit2() or deflateReset() and before the first call of Chris@4: deflate(). The text, time, os, extra field, name, and comment information Chris@4: in the provided gz_header structure are written to the gzip header (xflag is Chris@4: ignored -- the extra flags are set according to the compression level). The Chris@4: caller must assure that, if not Z_NULL, name and comment are terminated with Chris@4: a zero byte, and that if extra is not Z_NULL, that extra_len bytes are Chris@4: available there. If hcrc is true, a gzip header crc is included. Note that Chris@4: the current versions of the command-line version of gzip (up through version Chris@4: 1.3.x) do not support header crc's, and will report that it is a "multi-part Chris@4: gzip file" and give up. Chris@4: Chris@4: If deflateSetHeader is not used, the default gzip header has text false, Chris@4: the time set to zero, and os set to 255, with no extra, name, or comment Chris@4: fields. The gzip header is returned to the default state by deflateReset(). Chris@4: Chris@4: deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source Chris@4: stream state was inconsistent. Chris@4: */ Chris@4: Chris@4: /* Chris@4: ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, Chris@4: int windowBits)); Chris@4: Chris@4: This is another version of inflateInit with an extra parameter. The Chris@4: fields next_in, avail_in, zalloc, zfree and opaque must be initialized Chris@4: before by the caller. Chris@4: Chris@4: The windowBits parameter is the base two logarithm of the maximum window Chris@4: size (the size of the history buffer). It should be in the range 8..15 for Chris@4: this version of the library. The default value is 15 if inflateInit is used Chris@4: instead. windowBits must be greater than or equal to the windowBits value Chris@4: provided to deflateInit2() while compressing, or it must be equal to 15 if Chris@4: deflateInit2() was not used. If a compressed stream with a larger window Chris@4: size is given as input, inflate() will return with the error code Chris@4: Z_DATA_ERROR instead of trying to allocate a larger window. Chris@4: Chris@4: windowBits can also be zero to request that inflate use the window size in Chris@4: the zlib header of the compressed stream. Chris@4: Chris@4: windowBits can also be -8..-15 for raw inflate. In this case, -windowBits Chris@4: determines the window size. inflate() will then process raw deflate data, Chris@4: not looking for a zlib or gzip header, not generating a check value, and not Chris@4: looking for any check values for comparison at the end of the stream. This Chris@4: is for use with other formats that use the deflate compressed data format Chris@4: such as zip. Those formats provide their own check values. If a custom Chris@4: format is developed using the raw deflate format for compressed data, it is Chris@4: recommended that a check value such as an adler32 or a crc32 be applied to Chris@4: the uncompressed data as is done in the zlib, gzip, and zip formats. For Chris@4: most applications, the zlib format should be used as is. Note that comments Chris@4: above on the use in deflateInit2() applies to the magnitude of windowBits. Chris@4: Chris@4: windowBits can also be greater than 15 for optional gzip decoding. Add Chris@4: 32 to windowBits to enable zlib and gzip decoding with automatic header Chris@4: detection, or add 16 to decode only the gzip format (the zlib format will Chris@4: return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a Chris@4: crc32 instead of an adler32. Chris@4: Chris@4: inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough Chris@4: memory, Z_VERSION_ERROR if the zlib library version is incompatible with the Chris@4: version assumed by the caller, or Z_STREAM_ERROR if the parameters are Chris@4: invalid, such as a null pointer to the structure. msg is set to null if Chris@4: there is no error message. inflateInit2 does not perform any decompression Chris@4: apart from possibly reading the zlib header if present: actual decompression Chris@4: will be done by inflate(). (So next_in and avail_in may be modified, but Chris@4: next_out and avail_out are unused and unchanged.) The current implementation Chris@4: of inflateInit2() does not process any header information -- that is Chris@4: deferred until inflate() is called. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, Chris@4: const Bytef *dictionary, Chris@4: uInt dictLength)); Chris@4: /* Chris@4: Initializes the decompression dictionary from the given uncompressed byte Chris@4: sequence. This function must be called immediately after a call of inflate, Chris@4: if that call returned Z_NEED_DICT. The dictionary chosen by the compressor Chris@4: can be determined from the adler32 value returned by that call of inflate. Chris@4: The compressor and decompressor must use exactly the same dictionary (see Chris@4: deflateSetDictionary). For raw inflate, this function can be called at any Chris@4: time to set the dictionary. If the provided dictionary is smaller than the Chris@4: window and there is already data in the window, then the provided dictionary Chris@4: will amend what's there. The application must insure that the dictionary Chris@4: that was used for compression is provided. Chris@4: Chris@4: inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a Chris@4: parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is Chris@4: inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the Chris@4: expected one (incorrect adler32 value). inflateSetDictionary does not Chris@4: perform any decompression: this will be done by subsequent calls of Chris@4: inflate(). Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); Chris@4: /* Chris@4: Skips invalid compressed data until a possible full flush point (see above Chris@4: for the description of deflate with Z_FULL_FLUSH) can be found, or until all Chris@4: available input is skipped. No output is provided. Chris@4: Chris@4: inflateSync searches for a 00 00 FF FF pattern in the compressed data. Chris@4: All full flush points have this pattern, but not all occurences of this Chris@4: pattern are full flush points. Chris@4: Chris@4: inflateSync returns Z_OK if a possible full flush point has been found, Chris@4: Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point Chris@4: has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. Chris@4: In the success case, the application may save the current current value of Chris@4: total_in which indicates where valid compressed data was found. In the Chris@4: error case, the application may repeatedly call inflateSync, providing more Chris@4: input each time, until success or end of the input data. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, Chris@4: z_streamp source)); Chris@4: /* Chris@4: Sets the destination stream as a complete copy of the source stream. Chris@4: Chris@4: This function can be useful when randomly accessing a large stream. The Chris@4: first pass through the stream can periodically record the inflate state, Chris@4: allowing restarting inflate at those points when randomly accessing the Chris@4: stream. Chris@4: Chris@4: inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not Chris@4: enough memory, Z_STREAM_ERROR if the source stream state was inconsistent Chris@4: (such as zalloc being Z_NULL). msg is left unchanged in both source and Chris@4: destination. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); Chris@4: /* Chris@4: This function is equivalent to inflateEnd followed by inflateInit, Chris@4: but does not free and reallocate all the internal decompression state. The Chris@4: stream will keep attributes that may have been set by inflateInit2. Chris@4: Chris@4: inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source Chris@4: stream state was inconsistent (such as zalloc or state being Z_NULL). Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm, Chris@4: int windowBits)); Chris@4: /* Chris@4: This function is the same as inflateReset, but it also permits changing Chris@4: the wrap and window size requests. The windowBits parameter is interpreted Chris@4: the same as it is for inflateInit2. Chris@4: Chris@4: inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source Chris@4: stream state was inconsistent (such as zalloc or state being Z_NULL), or if Chris@4: the windowBits parameter is invalid. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, Chris@4: int bits, Chris@4: int value)); Chris@4: /* Chris@4: This function inserts bits in the inflate input stream. The intent is Chris@4: that this function is used to start inflating at a bit position in the Chris@4: middle of a byte. The provided bits will be used before any bytes are used Chris@4: from next_in. This function should only be used with raw inflate, and Chris@4: should be used before the first inflate() call after inflateInit2() or Chris@4: inflateReset(). bits must be less than or equal to 16, and that many of the Chris@4: least significant bits of value will be inserted in the input. Chris@4: Chris@4: If bits is negative, then the input stream bit buffer is emptied. Then Chris@4: inflatePrime() can be called again to put bits in the buffer. This is used Chris@4: to clear out bits leftover after feeding inflate a block description prior Chris@4: to feeding inflate codes. Chris@4: Chris@4: inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source Chris@4: stream state was inconsistent. Chris@4: */ Chris@4: Chris@4: ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); Chris@4: /* Chris@4: This function returns two values, one in the lower 16 bits of the return Chris@4: value, and the other in the remaining upper bits, obtained by shifting the Chris@4: return value down 16 bits. If the upper value is -1 and the lower value is Chris@4: zero, then inflate() is currently decoding information outside of a block. Chris@4: If the upper value is -1 and the lower value is non-zero, then inflate is in Chris@4: the middle of a stored block, with the lower value equaling the number of Chris@4: bytes from the input remaining to copy. If the upper value is not -1, then Chris@4: it is the number of bits back from the current bit position in the input of Chris@4: the code (literal or length/distance pair) currently being processed. In Chris@4: that case the lower value is the number of bytes already emitted for that Chris@4: code. Chris@4: Chris@4: A code is being processed if inflate is waiting for more input to complete Chris@4: decoding of the code, or if it has completed decoding but is waiting for Chris@4: more output space to write the literal or match data. Chris@4: Chris@4: inflateMark() is used to mark locations in the input data for random Chris@4: access, which may be at bit positions, and to note those cases where the Chris@4: output of a code may span boundaries of random access blocks. The current Chris@4: location in the input stream can be determined from avail_in and data_type Chris@4: as noted in the description for the Z_BLOCK flush parameter for inflate. Chris@4: Chris@4: inflateMark returns the value noted above or -1 << 16 if the provided Chris@4: source stream state was inconsistent. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, Chris@4: gz_headerp head)); Chris@4: /* Chris@4: inflateGetHeader() requests that gzip header information be stored in the Chris@4: provided gz_header structure. inflateGetHeader() may be called after Chris@4: inflateInit2() or inflateReset(), and before the first call of inflate(). Chris@4: As inflate() processes the gzip stream, head->done is zero until the header Chris@4: is completed, at which time head->done is set to one. If a zlib stream is Chris@4: being decoded, then head->done is set to -1 to indicate that there will be Chris@4: no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be Chris@4: used to force inflate() to return immediately after header processing is Chris@4: complete and before any actual data is decompressed. Chris@4: Chris@4: The text, time, xflags, and os fields are filled in with the gzip header Chris@4: contents. hcrc is set to true if there is a header CRC. (The header CRC Chris@4: was valid if done is set to one.) If extra is not Z_NULL, then extra_max Chris@4: contains the maximum number of bytes to write to extra. Once done is true, Chris@4: extra_len contains the actual extra field length, and extra contains the Chris@4: extra field, or that field truncated if extra_max is less than extra_len. Chris@4: If name is not Z_NULL, then up to name_max characters are written there, Chris@4: terminated with a zero unless the length is greater than name_max. If Chris@4: comment is not Z_NULL, then up to comm_max characters are written there, Chris@4: terminated with a zero unless the length is greater than comm_max. When any Chris@4: of extra, name, or comment are not Z_NULL and the respective field is not Chris@4: present in the header, then that field is set to Z_NULL to signal its Chris@4: absence. This allows the use of deflateSetHeader() with the returned Chris@4: structure to duplicate the header. However if those fields are set to Chris@4: allocated memory, then the application will need to save those pointers Chris@4: elsewhere so that they can be eventually freed. Chris@4: Chris@4: If inflateGetHeader is not used, then the header information is simply Chris@4: discarded. The header is always checked for validity, including the header Chris@4: CRC if present. inflateReset() will reset the process to discard the header Chris@4: information. The application would need to call inflateGetHeader() again to Chris@4: retrieve the header from the next gzip stream. Chris@4: Chris@4: inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source Chris@4: stream state was inconsistent. Chris@4: */ Chris@4: Chris@4: /* Chris@4: ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, Chris@4: unsigned char FAR *window)); Chris@4: Chris@4: Initialize the internal stream state for decompression using inflateBack() Chris@4: calls. The fields zalloc, zfree and opaque in strm must be initialized Chris@4: before the call. If zalloc and zfree are Z_NULL, then the default library- Chris@4: derived memory allocation routines are used. windowBits is the base two Chris@4: logarithm of the window size, in the range 8..15. window is a caller Chris@4: supplied buffer of that size. Except for special applications where it is Chris@4: assured that deflate was used with small window sizes, windowBits must be 15 Chris@4: and a 32K byte window must be supplied to be able to decompress general Chris@4: deflate streams. Chris@4: Chris@4: See inflateBack() for the usage of these routines. Chris@4: Chris@4: inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of Chris@4: the parameters are invalid, Z_MEM_ERROR if the internal state could not be Chris@4: allocated, or Z_VERSION_ERROR if the version of the library does not match Chris@4: the version of the header file. Chris@4: */ Chris@4: Chris@4: typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *)); Chris@4: typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); Chris@4: Chris@4: ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, Chris@4: in_func in, void FAR *in_desc, Chris@4: out_func out, void FAR *out_desc)); Chris@4: /* Chris@4: inflateBack() does a raw inflate with a single call using a call-back Chris@4: interface for input and output. This is more efficient than inflate() for Chris@4: file i/o applications in that it avoids copying between the output and the Chris@4: sliding window by simply making the window itself the output buffer. This Chris@4: function trusts the application to not change the output buffer passed by Chris@4: the output function, at least until inflateBack() returns. Chris@4: Chris@4: inflateBackInit() must be called first to allocate the internal state Chris@4: and to initialize the state with the user-provided window buffer. Chris@4: inflateBack() may then be used multiple times to inflate a complete, raw Chris@4: deflate stream with each call. inflateBackEnd() is then called to free the Chris@4: allocated state. Chris@4: Chris@4: A raw deflate stream is one with no zlib or gzip header or trailer. Chris@4: This routine would normally be used in a utility that reads zip or gzip Chris@4: files and writes out uncompressed files. The utility would decode the Chris@4: header and process the trailer on its own, hence this routine expects only Chris@4: the raw deflate stream to decompress. This is different from the normal Chris@4: behavior of inflate(), which expects either a zlib or gzip header and Chris@4: trailer around the deflate stream. Chris@4: Chris@4: inflateBack() uses two subroutines supplied by the caller that are then Chris@4: called by inflateBack() for input and output. inflateBack() calls those Chris@4: routines until it reads a complete deflate stream and writes out all of the Chris@4: uncompressed data, or until it encounters an error. The function's Chris@4: parameters and return types are defined above in the in_func and out_func Chris@4: typedefs. inflateBack() will call in(in_desc, &buf) which should return the Chris@4: number of bytes of provided input, and a pointer to that input in buf. If Chris@4: there is no input available, in() must return zero--buf is ignored in that Chris@4: case--and inflateBack() will return a buffer error. inflateBack() will call Chris@4: out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() Chris@4: should return zero on success, or non-zero on failure. If out() returns Chris@4: non-zero, inflateBack() will return with an error. Neither in() nor out() Chris@4: are permitted to change the contents of the window provided to Chris@4: inflateBackInit(), which is also the buffer that out() uses to write from. Chris@4: The length written by out() will be at most the window size. Any non-zero Chris@4: amount of input may be provided by in(). Chris@4: Chris@4: For convenience, inflateBack() can be provided input on the first call by Chris@4: setting strm->next_in and strm->avail_in. If that input is exhausted, then Chris@4: in() will be called. Therefore strm->next_in must be initialized before Chris@4: calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called Chris@4: immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in Chris@4: must also be initialized, and then if strm->avail_in is not zero, input will Chris@4: initially be taken from strm->next_in[0 .. strm->avail_in - 1]. Chris@4: Chris@4: The in_desc and out_desc parameters of inflateBack() is passed as the Chris@4: first parameter of in() and out() respectively when they are called. These Chris@4: descriptors can be optionally used to pass any information that the caller- Chris@4: supplied in() and out() functions need to do their job. Chris@4: Chris@4: On return, inflateBack() will set strm->next_in and strm->avail_in to Chris@4: pass back any unused input that was provided by the last in() call. The Chris@4: return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR Chris@4: if in() or out() returned an error, Z_DATA_ERROR if there was a format error Chris@4: in the deflate stream (in which case strm->msg is set to indicate the nature Chris@4: of the error), or Z_STREAM_ERROR if the stream was not properly initialized. Chris@4: In the case of Z_BUF_ERROR, an input or output error can be distinguished Chris@4: using strm->next_in which will be Z_NULL only if in() returned an error. If Chris@4: strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning Chris@4: non-zero. (in() will always be called before out(), so strm->next_in is Chris@4: assured to be defined if out() returns non-zero.) Note that inflateBack() Chris@4: cannot return Z_OK. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); Chris@4: /* Chris@4: All memory allocated by inflateBackInit() is freed. Chris@4: Chris@4: inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream Chris@4: state was inconsistent. Chris@4: */ Chris@4: Chris@4: ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); Chris@4: /* Return flags indicating compile-time options. Chris@4: Chris@4: Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: Chris@4: 1.0: size of uInt Chris@4: 3.2: size of uLong Chris@4: 5.4: size of voidpf (pointer) Chris@4: 7.6: size of z_off_t Chris@4: Chris@4: Compiler, assembler, and debug options: Chris@4: 8: DEBUG Chris@4: 9: ASMV or ASMINF -- use ASM code Chris@4: 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention Chris@4: 11: 0 (reserved) Chris@4: Chris@4: One-time table building (smaller code, but not thread-safe if true): Chris@4: 12: BUILDFIXED -- build static block decoding tables when needed Chris@4: 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed Chris@4: 14,15: 0 (reserved) Chris@4: Chris@4: Library content (indicates missing functionality): Chris@4: 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking Chris@4: deflate code when not needed) Chris@4: 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect Chris@4: and decode gzip streams (to avoid linking crc code) Chris@4: 18-19: 0 (reserved) Chris@4: Chris@4: Operation variations (changes in library functionality): Chris@4: 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate Chris@4: 21: FASTEST -- deflate algorithm with only one, lowest compression level Chris@4: 22,23: 0 (reserved) Chris@4: Chris@4: The sprintf variant used by gzprintf (zero is best): Chris@4: 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format Chris@4: 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! Chris@4: 26: 0 = returns value, 1 = void -- 1 means inferred string length returned Chris@4: Chris@4: Remainder: Chris@4: 27-31: 0 (reserved) Chris@4: */ Chris@4: Chris@4: #ifndef Z_SOLO Chris@4: Chris@4: /* utility functions */ Chris@4: Chris@4: /* Chris@4: The following utility functions are implemented on top of the basic Chris@4: stream-oriented functions. To simplify the interface, some default options Chris@4: are assumed (compression level and memory usage, standard memory allocation Chris@4: functions). The source code of these utility functions can be modified if Chris@4: you need special options. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, Chris@4: const Bytef *source, uLong sourceLen)); Chris@4: /* Chris@4: Compresses the source buffer into the destination buffer. sourceLen is Chris@4: the byte length of the source buffer. Upon entry, destLen is the total size Chris@4: of the destination buffer, which must be at least the value returned by Chris@4: compressBound(sourceLen). Upon exit, destLen is the actual size of the Chris@4: compressed buffer. Chris@4: Chris@4: compress returns Z_OK if success, Z_MEM_ERROR if there was not Chris@4: enough memory, Z_BUF_ERROR if there was not enough room in the output Chris@4: buffer. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, Chris@4: const Bytef *source, uLong sourceLen, Chris@4: int level)); Chris@4: /* Chris@4: Compresses the source buffer into the destination buffer. The level Chris@4: parameter has the same meaning as in deflateInit. sourceLen is the byte Chris@4: length of the source buffer. Upon entry, destLen is the total size of the Chris@4: destination buffer, which must be at least the value returned by Chris@4: compressBound(sourceLen). Upon exit, destLen is the actual size of the Chris@4: compressed buffer. Chris@4: Chris@4: compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough Chris@4: memory, Z_BUF_ERROR if there was not enough room in the output buffer, Chris@4: Z_STREAM_ERROR if the level parameter is invalid. Chris@4: */ Chris@4: Chris@4: ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); Chris@4: /* Chris@4: compressBound() returns an upper bound on the compressed size after Chris@4: compress() or compress2() on sourceLen bytes. It would be used before a Chris@4: compress() or compress2() call to allocate the destination buffer. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, Chris@4: const Bytef *source, uLong sourceLen)); Chris@4: /* Chris@4: Decompresses the source buffer into the destination buffer. sourceLen is Chris@4: the byte length of the source buffer. Upon entry, destLen is the total size Chris@4: of the destination buffer, which must be large enough to hold the entire Chris@4: uncompressed data. (The size of the uncompressed data must have been saved Chris@4: previously by the compressor and transmitted to the decompressor by some Chris@4: mechanism outside the scope of this compression library.) Upon exit, destLen Chris@4: is the actual size of the uncompressed buffer. Chris@4: Chris@4: uncompress returns Z_OK if success, Z_MEM_ERROR if there was not Chris@4: enough memory, Z_BUF_ERROR if there was not enough room in the output Chris@4: buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In Chris@4: the case where there is not enough room, uncompress() will fill the output Chris@4: buffer with the uncompressed data up to that point. Chris@4: */ Chris@4: Chris@4: /* gzip file access functions */ Chris@4: Chris@4: /* Chris@4: This library supports reading and writing files in gzip (.gz) format with Chris@4: an interface similar to that of stdio, using the functions that start with Chris@4: "gz". The gzip format is different from the zlib format. gzip is a gzip Chris@4: wrapper, documented in RFC 1952, wrapped around a deflate stream. Chris@4: */ Chris@4: Chris@4: typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ Chris@4: Chris@4: /* Chris@4: ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); Chris@4: Chris@4: Opens a gzip (.gz) file for reading or writing. The mode parameter is as Chris@4: in fopen ("rb" or "wb") but can also include a compression level ("wb9") or Chris@4: a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only Chris@4: compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F' Chris@4: for fixed code compression as in "wb9F". (See the description of Chris@4: deflateInit2 for more information about the strategy parameter.) 'T' will Chris@4: request transparent writing or appending with no compression and not using Chris@4: the gzip format. Chris@4: Chris@4: "a" can be used instead of "w" to request that the gzip stream that will Chris@4: be written be appended to the file. "+" will result in an error, since Chris@4: reading and writing to the same gzip file is not supported. The addition of Chris@4: "x" when writing will create the file exclusively, which fails if the file Chris@4: already exists. On systems that support it, the addition of "e" when Chris@4: reading or writing will set the flag to close the file on an execve() call. Chris@4: Chris@4: These functions, as well as gzip, will read and decode a sequence of gzip Chris@4: streams in a file. The append function of gzopen() can be used to create Chris@4: such a file. (Also see gzflush() for another way to do this.) When Chris@4: appending, gzopen does not test whether the file begins with a gzip stream, Chris@4: nor does it look for the end of the gzip streams to begin appending. gzopen Chris@4: will simply append a gzip stream to the existing file. Chris@4: Chris@4: gzopen can be used to read a file which is not in gzip format; in this Chris@4: case gzread will directly read from the file without decompression. When Chris@4: reading, this will be detected automatically by looking for the magic two- Chris@4: byte gzip header. Chris@4: Chris@4: gzopen returns NULL if the file could not be opened, if there was Chris@4: insufficient memory to allocate the gzFile state, or if an invalid mode was Chris@4: specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). Chris@4: errno can be checked to determine if the reason gzopen failed was that the Chris@4: file could not be opened. Chris@4: */ Chris@4: Chris@4: ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); Chris@4: /* Chris@4: gzdopen associates a gzFile with the file descriptor fd. File descriptors Chris@4: are obtained from calls like open, dup, creat, pipe or fileno (if the file Chris@4: has been previously opened with fopen). The mode parameter is as in gzopen. Chris@4: Chris@4: The next call of gzclose on the returned gzFile will also close the file Chris@4: descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor Chris@4: fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, Chris@4: mode);. The duplicated descriptor should be saved to avoid a leak, since Chris@4: gzdopen does not close fd if it fails. If you are using fileno() to get the Chris@4: file descriptor from a FILE *, then you will have to use dup() to avoid Chris@4: double-close()ing the file descriptor. Both gzclose() and fclose() will Chris@4: close the associated file descriptor, so they need to have different file Chris@4: descriptors. Chris@4: Chris@4: gzdopen returns NULL if there was insufficient memory to allocate the Chris@4: gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not Chris@4: provided, or '+' was provided), or if fd is -1. The file descriptor is not Chris@4: used until the next gz* read, write, seek, or close operation, so gzdopen Chris@4: will not detect if fd is invalid (unless fd is -1). Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size)); Chris@4: /* Chris@4: Set the internal buffer size used by this library's functions. The Chris@4: default buffer size is 8192 bytes. This function must be called after Chris@4: gzopen() or gzdopen(), and before any other calls that read or write the Chris@4: file. The buffer memory allocation is always deferred to the first read or Chris@4: write. Two buffers are allocated, either both of the specified size when Chris@4: writing, or one of the specified size and the other twice that size when Chris@4: reading. A larger buffer size of, for example, 64K or 128K bytes will Chris@4: noticeably increase the speed of decompression (reading). Chris@4: Chris@4: The new buffer size also affects the maximum length for gzprintf(). Chris@4: Chris@4: gzbuffer() returns 0 on success, or -1 on failure, such as being called Chris@4: too late. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); Chris@4: /* Chris@4: Dynamically update the compression level or strategy. See the description Chris@4: of deflateInit2 for the meaning of these parameters. Chris@4: Chris@4: gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not Chris@4: opened for writing. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); Chris@4: /* Chris@4: Reads the given number of uncompressed bytes from the compressed file. If Chris@4: the input file is not in gzip format, gzread copies the given number of Chris@4: bytes into the buffer directly from the file. Chris@4: Chris@4: After reaching the end of a gzip stream in the input, gzread will continue Chris@4: to read, looking for another gzip stream. Any number of gzip streams may be Chris@4: concatenated in the input file, and will all be decompressed by gzread(). Chris@4: If something other than a gzip stream is encountered after a gzip stream, Chris@4: that remaining trailing garbage is ignored (and no error is returned). Chris@4: Chris@4: gzread can be used to read a gzip file that is being concurrently written. Chris@4: Upon reaching the end of the input, gzread will return with the available Chris@4: data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then Chris@4: gzclearerr can be used to clear the end of file indicator in order to permit Chris@4: gzread to be tried again. Z_OK indicates that a gzip stream was completed Chris@4: on the last gzread. Z_BUF_ERROR indicates that the input file ended in the Chris@4: middle of a gzip stream. Note that gzread does not return -1 in the event Chris@4: of an incomplete gzip stream. This error is deferred until gzclose(), which Chris@4: will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip Chris@4: stream. Alternatively, gzerror can be used before gzclose to detect this Chris@4: case. Chris@4: Chris@4: gzread returns the number of uncompressed bytes actually read, less than Chris@4: len for end of file, or -1 for error. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT gzwrite OF((gzFile file, Chris@4: voidpc buf, unsigned len)); Chris@4: /* Chris@4: Writes the given number of uncompressed bytes into the compressed file. Chris@4: gzwrite returns the number of uncompressed bytes written or 0 in case of Chris@4: error. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...)); Chris@4: /* Chris@4: Converts, formats, and writes the arguments to the compressed file under Chris@4: control of the format string, as in fprintf. gzprintf returns the number of Chris@4: uncompressed bytes actually written, or 0 in case of error. The number of Chris@4: uncompressed bytes written is limited to 8191, or one less than the buffer Chris@4: size given to gzbuffer(). The caller should assure that this limit is not Chris@4: exceeded. If it is exceeded, then gzprintf() will return an error (0) with Chris@4: nothing written. In this case, there may also be a buffer overflow with Chris@4: unpredictable consequences, which is possible only if zlib was compiled with Chris@4: the insecure functions sprintf() or vsprintf() because the secure snprintf() Chris@4: or vsnprintf() functions were not available. This can be determined using Chris@4: zlibCompileFlags(). Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); Chris@4: /* Chris@4: Writes the given null-terminated string to the compressed file, excluding Chris@4: the terminating null character. Chris@4: Chris@4: gzputs returns the number of characters written, or -1 in case of error. Chris@4: */ Chris@4: Chris@4: ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); Chris@4: /* Chris@4: Reads bytes from the compressed file until len-1 characters are read, or a Chris@4: newline character is read and transferred to buf, or an end-of-file Chris@4: condition is encountered. If any characters are read or if len == 1, the Chris@4: string is terminated with a null character. If no characters are read due Chris@4: to an end-of-file or len < 1, then the buffer is left untouched. Chris@4: Chris@4: gzgets returns buf which is a null-terminated string, or it returns NULL Chris@4: for end-of-file or in case of error. If there was an error, the contents at Chris@4: buf are indeterminate. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); Chris@4: /* Chris@4: Writes c, converted to an unsigned char, into the compressed file. gzputc Chris@4: returns the value that was written, or -1 in case of error. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); Chris@4: /* Chris@4: Reads one byte from the compressed file. gzgetc returns this byte or -1 Chris@4: in case of end of file or error. This is implemented as a macro for speed. Chris@4: As such, it does not do all of the checking the other functions do. I.e. Chris@4: it does not check to see if file is NULL, nor whether the structure file Chris@4: points to has been clobbered or not. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); Chris@4: /* Chris@4: Push one character back onto the stream to be read as the first character Chris@4: on the next read. At least one character of push-back is allowed. Chris@4: gzungetc() returns the character pushed, or -1 on failure. gzungetc() will Chris@4: fail if c is -1, and may fail if a character has been pushed but not read Chris@4: yet. If gzungetc is used immediately after gzopen or gzdopen, at least the Chris@4: output buffer size of pushed characters is allowed. (See gzbuffer above.) Chris@4: The pushed character will be discarded if the stream is repositioned with Chris@4: gzseek() or gzrewind(). Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); Chris@4: /* Chris@4: Flushes all pending output into the compressed file. The parameter flush Chris@4: is as in the deflate() function. The return value is the zlib error number Chris@4: (see function gzerror below). gzflush is only permitted when writing. Chris@4: Chris@4: If the flush parameter is Z_FINISH, the remaining data is written and the Chris@4: gzip stream is completed in the output. If gzwrite() is called again, a new Chris@4: gzip stream will be started in the output. gzread() is able to read such Chris@4: concatented gzip streams. Chris@4: Chris@4: gzflush should be called only when strictly necessary because it will Chris@4: degrade compression if called too often. Chris@4: */ Chris@4: Chris@4: /* Chris@4: ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, Chris@4: z_off_t offset, int whence)); Chris@4: Chris@4: Sets the starting position for the next gzread or gzwrite on the given Chris@4: compressed file. The offset represents a number of bytes in the Chris@4: uncompressed data stream. The whence parameter is defined as in lseek(2); Chris@4: the value SEEK_END is not supported. Chris@4: Chris@4: If the file is opened for reading, this function is emulated but can be Chris@4: extremely slow. If the file is opened for writing, only forward seeks are Chris@4: supported; gzseek then compresses a sequence of zeroes up to the new Chris@4: starting position. Chris@4: Chris@4: gzseek returns the resulting offset location as measured in bytes from Chris@4: the beginning of the uncompressed stream, or -1 in case of error, in Chris@4: particular if the file is opened for writing and the new starting position Chris@4: would be before the current position. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); Chris@4: /* Chris@4: Rewinds the given file. This function is supported only for reading. Chris@4: Chris@4: gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) Chris@4: */ Chris@4: Chris@4: /* Chris@4: ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); Chris@4: Chris@4: Returns the starting position for the next gzread or gzwrite on the given Chris@4: compressed file. This position represents a number of bytes in the Chris@4: uncompressed data stream, and is zero when starting, even if appending or Chris@4: reading a gzip stream from the middle of a file using gzdopen(). Chris@4: Chris@4: gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) Chris@4: */ Chris@4: Chris@4: /* Chris@4: ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); Chris@4: Chris@4: Returns the current offset in the file being read or written. This offset Chris@4: includes the count of bytes that precede the gzip stream, for example when Chris@4: appending or when using gzdopen() for reading. When reading, the offset Chris@4: does not include as yet unused buffered input. This information can be used Chris@4: for a progress indicator. On error, gzoffset() returns -1. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT gzeof OF((gzFile file)); Chris@4: /* Chris@4: Returns true (1) if the end-of-file indicator has been set while reading, Chris@4: false (0) otherwise. Note that the end-of-file indicator is set only if the Chris@4: read tried to go past the end of the input, but came up short. Therefore, Chris@4: just like feof(), gzeof() may return false even if there is no more data to Chris@4: read, in the event that the last read request was for the exact number of Chris@4: bytes remaining in the input file. This will happen if the input file size Chris@4: is an exact multiple of the buffer size. Chris@4: Chris@4: If gzeof() returns true, then the read functions will return no more data, Chris@4: unless the end-of-file indicator is reset by gzclearerr() and the input file Chris@4: has grown since the previous end of file was detected. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); Chris@4: /* Chris@4: Returns true (1) if file is being copied directly while reading, or false Chris@4: (0) if file is a gzip stream being decompressed. Chris@4: Chris@4: If the input file is empty, gzdirect() will return true, since the input Chris@4: does not contain a gzip stream. Chris@4: Chris@4: If gzdirect() is used immediately after gzopen() or gzdopen() it will Chris@4: cause buffers to be allocated to allow reading the file to determine if it Chris@4: is a gzip file. Therefore if gzbuffer() is used, it should be called before Chris@4: gzdirect(). Chris@4: Chris@4: When writing, gzdirect() returns true (1) if transparent writing was Chris@4: requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: Chris@4: gzdirect() is not needed when writing. Transparent writing must be Chris@4: explicitly requested, so the application already knows the answer. When Chris@4: linking statically, using gzdirect() will include all of the zlib code for Chris@4: gzip file reading and decompression, which may not be desired.) Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT gzclose OF((gzFile file)); Chris@4: /* Chris@4: Flushes all pending output if necessary, closes the compressed file and Chris@4: deallocates the (de)compression state. Note that once file is closed, you Chris@4: cannot call gzerror with file, since its structures have been deallocated. Chris@4: gzclose must not be called more than once on the same file, just as free Chris@4: must not be called more than once on the same allocation. Chris@4: Chris@4: gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a Chris@4: file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the Chris@4: last read ended in the middle of a gzip stream, or Z_OK on success. Chris@4: */ Chris@4: Chris@4: ZEXTERN int ZEXPORT gzclose_r OF((gzFile file)); Chris@4: ZEXTERN int ZEXPORT gzclose_w OF((gzFile file)); Chris@4: /* Chris@4: Same as gzclose(), but gzclose_r() is only for use when reading, and Chris@4: gzclose_w() is only for use when writing or appending. The advantage to Chris@4: using these instead of gzclose() is that they avoid linking in zlib Chris@4: compression or decompression code that is not used when only reading or only Chris@4: writing respectively. If gzclose() is used, then both compression and Chris@4: decompression code will be included the application when linking to a static Chris@4: zlib library. Chris@4: */ Chris@4: Chris@4: ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); Chris@4: /* Chris@4: Returns the error message for the last error which occurred on the given Chris@4: compressed file. errnum is set to zlib error number. If an error occurred Chris@4: in the file system and not in the compression library, errnum is set to Chris@4: Z_ERRNO and the application may consult errno to get the exact error code. Chris@4: Chris@4: The application must not modify the returned string. Future calls to Chris@4: this function may invalidate the previously returned string. If file is Chris@4: closed, then the string previously returned by gzerror will no longer be Chris@4: available. Chris@4: Chris@4: gzerror() should be used to distinguish errors from end-of-file for those Chris@4: functions above that do not distinguish those cases in their return values. Chris@4: */ Chris@4: Chris@4: ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); Chris@4: /* Chris@4: Clears the error and end-of-file flags for file. This is analogous to the Chris@4: clearerr() function in stdio. This is useful for continuing to read a gzip Chris@4: file that is being written concurrently. Chris@4: */ Chris@4: Chris@4: #endif /* !Z_SOLO */ Chris@4: Chris@4: /* checksum functions */ Chris@4: Chris@4: /* Chris@4: These functions are not related to compression but are exported Chris@4: anyway because they might be useful in applications using the compression Chris@4: library. Chris@4: */ Chris@4: Chris@4: ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); Chris@4: /* Chris@4: Update a running Adler-32 checksum with the bytes buf[0..len-1] and Chris@4: return the updated checksum. If buf is Z_NULL, this function returns the Chris@4: required initial value for the checksum. Chris@4: Chris@4: An Adler-32 checksum is almost as reliable as a CRC32 but can be computed Chris@4: much faster. Chris@4: Chris@4: Usage example: Chris@4: Chris@4: uLong adler = adler32(0L, Z_NULL, 0); Chris@4: Chris@4: while (read_buffer(buffer, length) != EOF) { Chris@4: adler = adler32(adler, buffer, length); Chris@4: } Chris@4: if (adler != original_adler) error(); Chris@4: */ Chris@4: Chris@4: /* Chris@4: ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, Chris@4: z_off_t len2)); Chris@4: Chris@4: Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 Chris@4: and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for Chris@4: each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of Chris@4: seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note Chris@4: that the z_off_t type (like off_t) is a signed integer. If len2 is Chris@4: negative, the result has no meaning or utility. Chris@4: */ Chris@4: Chris@4: ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); Chris@4: /* Chris@4: Update a running CRC-32 with the bytes buf[0..len-1] and return the Chris@4: updated CRC-32. If buf is Z_NULL, this function returns the required Chris@4: initial value for the crc. Pre- and post-conditioning (one's complement) is Chris@4: performed within this function so it shouldn't be done by the application. Chris@4: Chris@4: Usage example: Chris@4: Chris@4: uLong crc = crc32(0L, Z_NULL, 0); Chris@4: Chris@4: while (read_buffer(buffer, length) != EOF) { Chris@4: crc = crc32(crc, buffer, length); Chris@4: } Chris@4: if (crc != original_crc) error(); Chris@4: */ Chris@4: Chris@4: /* Chris@4: ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); Chris@4: Chris@4: Combine two CRC-32 check values into one. For two sequences of bytes, Chris@4: seq1 and seq2 with lengths len1 and len2, CRC-32 check values were Chris@4: calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 Chris@4: check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and Chris@4: len2. Chris@4: */ Chris@4: Chris@4: Chris@4: /* various hacks, don't look :) */ Chris@4: Chris@4: /* deflateInit and inflateInit are macros to allow checking the zlib version Chris@4: * and the compiler's view of z_stream: Chris@4: */ Chris@4: ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, Chris@4: const char *version, int stream_size)); Chris@4: ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, Chris@4: const char *version, int stream_size)); Chris@4: ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, Chris@4: int windowBits, int memLevel, Chris@4: int strategy, const char *version, Chris@4: int stream_size)); Chris@4: ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, Chris@4: const char *version, int stream_size)); Chris@4: ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, Chris@4: unsigned char FAR *window, Chris@4: const char *version, Chris@4: int stream_size)); Chris@4: #define deflateInit(strm, level) \ Chris@4: deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) Chris@4: #define inflateInit(strm) \ Chris@4: inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) Chris@4: #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ Chris@4: deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ Chris@4: (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) Chris@4: #define inflateInit2(strm, windowBits) \ Chris@4: inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ Chris@4: (int)sizeof(z_stream)) Chris@4: #define inflateBackInit(strm, windowBits, window) \ Chris@4: inflateBackInit_((strm), (windowBits), (window), \ Chris@4: ZLIB_VERSION, (int)sizeof(z_stream)) Chris@4: Chris@4: #ifndef Z_SOLO Chris@4: Chris@4: /* gzgetc() macro and its supporting function and exposed data structure. Note Chris@4: * that the real internal state is much larger than the exposed structure. Chris@4: * This abbreviated structure exposes just enough for the gzgetc() macro. The Chris@4: * user should not mess with these exposed elements, since their names or Chris@4: * behavior could change in the future, perhaps even capriciously. They can Chris@4: * only be used by the gzgetc() macro. You have been warned. Chris@4: */ Chris@4: struct gzFile_s { Chris@4: unsigned have; Chris@4: unsigned char *next; Chris@4: z_off64_t pos; Chris@4: }; Chris@4: ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */ Chris@4: #ifdef Z_PREFIX_SET Chris@4: # undef z_gzgetc Chris@4: # define z_gzgetc(g) \ Chris@4: ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g)) Chris@4: #else Chris@4: # define gzgetc(g) \ Chris@4: ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g)) Chris@4: #endif Chris@4: Chris@4: /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or Chris@4: * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if Chris@4: * both are true, the application gets the *64 functions, and the regular Chris@4: * functions are changed to 64 bits) -- in case these are set on systems Chris@4: * without large file support, _LFS64_LARGEFILE must also be true Chris@4: */ Chris@4: #ifdef Z_LARGE64 Chris@4: ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); Chris@4: ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); Chris@4: ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); Chris@4: ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); Chris@4: ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); Chris@4: ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); Chris@4: #endif Chris@4: Chris@4: #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64) Chris@4: # ifdef Z_PREFIX_SET Chris@4: # define z_gzopen z_gzopen64 Chris@4: # define z_gzseek z_gzseek64 Chris@4: # define z_gztell z_gztell64 Chris@4: # define z_gzoffset z_gzoffset64 Chris@4: # define z_adler32_combine z_adler32_combine64 Chris@4: # define z_crc32_combine z_crc32_combine64 Chris@4: # else Chris@4: # define gzopen gzopen64 Chris@4: # define gzseek gzseek64 Chris@4: # define gztell gztell64 Chris@4: # define gzoffset gzoffset64 Chris@4: # define adler32_combine adler32_combine64 Chris@4: # define crc32_combine crc32_combine64 Chris@4: # endif Chris@4: # ifndef Z_LARGE64 Chris@4: ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); Chris@4: ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int)); Chris@4: ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile)); Chris@4: ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile)); Chris@4: ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t)); Chris@4: ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t)); Chris@4: # endif Chris@4: #else Chris@4: ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); Chris@4: ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); Chris@4: ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); Chris@4: ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); Chris@4: ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); Chris@4: ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); Chris@4: #endif Chris@4: Chris@4: #else /* Z_SOLO */ Chris@4: Chris@4: ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); Chris@4: ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); Chris@4: Chris@4: #endif /* !Z_SOLO */ Chris@4: Chris@4: /* hack for buggy compilers */ Chris@4: #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) Chris@4: struct internal_state {int dummy;}; Chris@4: #endif Chris@4: Chris@4: /* undocumented functions */ Chris@4: ZEXTERN const char * ZEXPORT zError OF((int)); Chris@4: ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); Chris@4: ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void)); Chris@4: ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); Chris@4: ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp)); Chris@4: ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp)); Chris@4: #if defined(_WIN32) && !defined(Z_SOLO) Chris@4: ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path, Chris@4: const char *mode)); Chris@4: #endif Chris@4: Chris@4: #ifdef __cplusplus Chris@4: } Chris@4: #endif Chris@4: Chris@4: #endif /* ZLIB_H */