| /* zlib.h -- interface of the 'zlib' general purpose compression library␊ |
| version 1.2.5, April 19th, 2010␊ |
| ␊ |
| Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler␊ |
| ␊ |
| This software is provided 'as-is', without any express or implied␊ |
| warranty. In no event will the authors be held liable for any damages␊ |
| arising from the use of this software.␊ |
| ␊ |
| Permission is granted to anyone to use this software for any purpose,␊ |
| including commercial applications, and to alter it and redistribute it␊ |
| freely, subject to the following restrictions:␊ |
| ␊ |
| 1. The origin of this software must not be misrepresented; you must not␊ |
| claim that you wrote the original software. If you use this software␊ |
| in a product, an acknowledgment in the product documentation would be␊ |
| appreciated but is not required.␊ |
| 2. Altered source versions must be plainly marked as such, and must not be␊ |
| misrepresented as being the original software.␊ |
| 3. This notice may not be removed or altered from any source distribution.␊ |
| ␊ |
| Jean-loup Gailly Mark Adler␊ |
| jloup@gzip.org madler@alumni.caltech.edu␊ |
| ␊ |
| ␊ |
| The data format used by the zlib library is described by RFCs (Request for␊ |
| Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt␊ |
| (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).␊ |
| */␊ |
| ␊ |
| #ifndef ZLIB_H␊ |
| #define ZLIB_H␊ |
| ␊ |
| #include "zconf.h"␊ |
| ␊ |
| #ifdef __cplusplus␊ |
| extern "C" {␊ |
| #endif␊ |
| ␊ |
| #define ZLIB_VERSION "1.2.5"␊ |
| #define ZLIB_VERNUM 0x1250␊ |
| #define ZLIB_VER_MAJOR 1␊ |
| #define ZLIB_VER_MINOR 2␊ |
| #define ZLIB_VER_REVISION 5␊ |
| #define ZLIB_VER_SUBREVISION 0␊ |
| ␊ |
| /*␊ |
| The 'zlib' compression library provides in-memory compression and␊ |
| decompression functions, including integrity checks of the uncompressed data.␊ |
| This version of the library supports only one compression method (deflation)␊ |
| but other algorithms will be added later and will have the same stream␊ |
| interface.␊ |
| ␊ |
| Compression can be done in a single step if the buffers are large enough,␊ |
| or can be done by repeated calls of the compression function. In the latter␊ |
| case, the application must provide more input and/or consume the output␊ |
| (providing more output space) before each call.␊ |
| ␊ |
| The compressed data format used by default by the in-memory functions is␊ |
| the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped␊ |
| around a deflate stream, which is itself documented in RFC 1951.␊ |
| ␊ |
| The library also supports reading and writing files in gzip (.gz) format␊ |
| with an interface similar to that of stdio using the functions that start␊ |
| with "gz". The gzip format is different from the zlib format. gzip is a␊ |
| gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.␊ |
| ␊ |
| This library can optionally read and write gzip streams in memory as well.␊ |
| ␊ |
| The zlib format was designed to be compact and fast for use in memory␊ |
| and on communications channels. The gzip format was designed for single-␊ |
| file compression on file systems, has a larger header than zlib to maintain␊ |
| directory information, and uses a different, slower check method than zlib.␊ |
| ␊ |
| The library does not install any signal handler. The decoder checks␊ |
| the consistency of the compressed data, so the library should never crash␊ |
| even in case of corrupted input.␊ |
| */␊ |
| ␊ |
| typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));␊ |
| typedef void (*free_func) OF((voidpf opaque, voidpf address));␊ |
| ␊ |
| struct internal_state;␊ |
| ␊ |
| typedef struct z_stream_s {␊ |
| Bytef *next_in; /* next input byte */␊ |
| uInt avail_in; /* number of bytes available at next_in */␊ |
| uLong total_in; /* total nb of input bytes read so far */␊ |
| ␊ |
| Bytef *next_out; /* next output byte should be put there */␊ |
| uInt avail_out; /* remaining free space at next_out */␊ |
| uLong total_out; /* total nb of bytes output so far */␊ |
| ␊ |
| char *msg; /* last error message, NULL if no error */␊ |
| struct internal_state FAR *state; /* not visible by applications */␊ |
| ␊ |
| alloc_func zalloc; /* used to allocate the internal state */␊ |
| free_func zfree; /* used to free the internal state */␊ |
| voidpf opaque; /* private data object passed to zalloc and zfree */␊ |
| ␊ |
| int data_type; /* best guess about the data type: binary or text */␊ |
| uLong adler; /* adler32 value of the uncompressed data */␊ |
| uLong reserved; /* reserved for future use */␊ |
| } z_stream;␊ |
| ␊ |
| typedef z_stream FAR *z_streamp;␊ |
| ␊ |
| /*␊ |
| gzip header information passed to and from zlib routines. See RFC 1952␊ |
| for more details on the meanings of these fields.␊ |
| */␊ |
| typedef struct gz_header_s {␊ |
| int text; /* true if compressed data believed to be text */␊ |
| uLong time; /* modification time */␊ |
| int xflags; /* extra flags (not used when writing a gzip file) */␊ |
| int os; /* operating system */␊ |
| Bytef *extra; /* pointer to extra field or Z_NULL if none */␊ |
| uInt extra_len; /* extra field length (valid if extra != Z_NULL) */␊ |
| uInt extra_max; /* space at extra (only when reading header) */␊ |
| Bytef *name; /* pointer to zero-terminated file name or Z_NULL */␊ |
| uInt name_max; /* space at name (only when reading header) */␊ |
| Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */␊ |
| uInt comm_max; /* space at comment (only when reading header) */␊ |
| int hcrc; /* true if there was or will be a header crc */␊ |
| int done; /* true when done reading gzip header (not used␊ |
| when writing a gzip file) */␊ |
| } gz_header;␊ |
| ␊ |
| typedef gz_header FAR *gz_headerp;␊ |
| ␊ |
| /*␊ |
| The application must update next_in and avail_in when avail_in has dropped␊ |
| to zero. It must update next_out and avail_out when avail_out has dropped␊ |
| to zero. The application must initialize zalloc, zfree and opaque before␊ |
| calling the init function. All other fields are set by the compression␊ |
| library and must not be updated by the application.␊ |
| ␊ |
| The opaque value provided by the application will be passed as the first␊ |
| parameter for calls of zalloc and zfree. This can be useful for custom␊ |
| memory management. The compression library attaches no meaning to the␊ |
| opaque value.␊ |
| ␊ |
| zalloc must return Z_NULL if there is not enough memory for the object.␊ |
| If zlib is used in a multi-threaded application, zalloc and zfree must be␊ |
| thread safe.␊ |
| ␊ |
| On 16-bit systems, the functions zalloc and zfree must be able to allocate␊ |
| exactly 65536 bytes, but will not be required to allocate more than this if␊ |
| the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers␊ |
| returned by zalloc for objects of exactly 65536 bytes *must* have their␊ |
| offset normalized to zero. The default allocation function provided by this␊ |
| library ensures this (see zutil.c). To reduce memory requirements and avoid␊ |
| any allocation of 64K objects, at the expense of compression ratio, compile␊ |
| the library with -DMAX_WBITS=14 (see zconf.h).␊ |
| ␊ |
| The fields total_in and total_out can be used for statistics or progress␊ |
| reports. After compression, total_in holds the total size of the␊ |
| uncompressed data and may be saved for use in the decompressor (particularly␊ |
| if the decompressor wants to decompress everything in a single step).␊ |
| */␊ |
| ␊ |
| /* constants */␊ |
| ␊ |
| #define Z_NO_FLUSH 0␊ |
| #define Z_PARTIAL_FLUSH 1␊ |
| #define Z_SYNC_FLUSH 2␊ |
| #define Z_FULL_FLUSH 3␊ |
| #define Z_FINISH 4␊ |
| #define Z_BLOCK 5␊ |
| #define Z_TREES 6␊ |
| /* Allowed flush values; see deflate() and inflate() below for details */␊ |
| ␊ |
| #define Z_OK 0␊ |
| #define Z_STREAM_END 1␊ |
| #define Z_NEED_DICT 2␊ |
| #define Z_ERRNO (-1)␊ |
| #define Z_STREAM_ERROR (-2)␊ |
| #define Z_DATA_ERROR (-3)␊ |
| #define Z_MEM_ERROR (-4)␊ |
| #define Z_BUF_ERROR (-5)␊ |
| #define Z_VERSION_ERROR (-6)␊ |
| /* Return codes for the compression/decompression functions. Negative values␊ |
| * are errors, positive values are used for special but normal events.␊ |
| */␊ |
| ␊ |
| #define Z_NO_COMPRESSION 0␊ |
| #define Z_BEST_SPEED 1␊ |
| #define Z_BEST_COMPRESSION 9␊ |
| #define Z_DEFAULT_COMPRESSION (-1)␊ |
| /* compression levels */␊ |
| ␊ |
| #define Z_FILTERED 1␊ |
| #define Z_HUFFMAN_ONLY 2␊ |
| #define Z_RLE 3␊ |
| #define Z_FIXED 4␊ |
| #define Z_DEFAULT_STRATEGY 0␊ |
| /* compression strategy; see deflateInit2() below for details */␊ |
| ␊ |
| #define Z_BINARY 0␊ |
| #define Z_TEXT 1␊ |
| #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */␊ |
| #define Z_UNKNOWN 2␊ |
| /* Possible values of the data_type field (though see inflate()) */␊ |
| ␊ |
| #define Z_DEFLATED 8␊ |
| /* The deflate compression method (the only one supported in this version) */␊ |
| ␊ |
| #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */␊ |
| ␊ |
| #define zlib_version zlibVersion()␊ |
| /* for compatibility with versions < 1.0.2 */␊ |
| ␊ |
| ␊ |
| /* basic functions */␊ |
| ␊ |
| ZEXTERN const char * ZEXPORT zlibVersion OF((void));␊ |
| /* The application can compare zlibVersion and ZLIB_VERSION for consistency.␊ |
| If the first character differs, the library code actually used is not␊ |
| compatible with the zlib.h header file used by the application. This check␊ |
| is automatically made by deflateInit and inflateInit.␊ |
| */␊ |
| ␊ |
| /*␊ |
| ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));␊ |
| ␊ |
| Initializes the internal stream state for compression. The fields␊ |
| zalloc, zfree and opaque must be initialized before by the caller. If␊ |
| zalloc and zfree are set to Z_NULL, deflateInit updates them to use default␊ |
| allocation functions.␊ |
| ␊ |
| The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:␊ |
| 1 gives best speed, 9 gives best compression, 0 gives no compression at all␊ |
| (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION␊ |
| requests a default compromise between speed and compression (currently␊ |
| equivalent to level 6).␊ |
| ␊ |
| deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough␊ |
| memory, Z_STREAM_ERROR if level is not a valid compression level, or␊ |
| Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible␊ |
| with the version assumed by the caller (ZLIB_VERSION). msg is set to null␊ |
| if there is no error message. deflateInit does not perform any compression:␊ |
| this will be done by deflate().␊ |
| */␊ |
| ␊ |
| ␊ |
| ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));␊ |
| /*␊ |
| deflate compresses as much data as possible, and stops when the input␊ |
| buffer becomes empty or the output buffer becomes full. It may introduce␊ |
| some output latency (reading input without producing any output) except when␊ |
| forced to flush.␊ |
| ␊ |
| The detailed semantics are as follows. deflate performs one or both of the␊ |
| following actions:␊ |
| ␊ |
| - Compress more input starting at next_in and update next_in and avail_in␊ |
| accordingly. If not all input can be processed (because there is not␊ |
| enough room in the output buffer), next_in and avail_in are updated and␊ |
| processing will resume at this point for the next call of deflate().␊ |
| ␊ |
| - Provide more output starting at next_out and update next_out and avail_out␊ |
| accordingly. This action is forced if the parameter flush is non zero.␊ |
| Forcing flush frequently degrades the compression ratio, so this parameter␊ |
| should be set only when necessary (in interactive applications). Some␊ |
| output may be provided even if flush is not set.␊ |
| ␊ |
| Before the call of deflate(), the application should ensure that at least␊ |
| one of the actions is possible, by providing more input and/or consuming more␊ |
| output, and updating avail_in or avail_out accordingly; avail_out should␊ |
| never be zero before the call. The application can consume the compressed␊ |
| output when it wants, for example when the output buffer is full (avail_out␊ |
| == 0), or after each call of deflate(). If deflate returns Z_OK and with␊ |
| zero avail_out, it must be called again after making room in the output␊ |
| buffer because there might be more output pending.␊ |
| ␊ |
| Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to␊ |
| decide how much data to accumulate before producing output, in order to␊ |
| maximize compression.␊ |
| ␊ |
| If the parameter flush is set to Z_SYNC_FLUSH, all pending output is␊ |
| flushed to the output buffer and the output is aligned on a byte boundary, so␊ |
| that the decompressor can get all input data available so far. (In␊ |
| particular avail_in is zero after the call if enough output space has been␊ |
| provided before the call.) Flushing may degrade compression for some␊ |
| compression algorithms and so it should be used only when necessary. This␊ |
| completes the current deflate block and follows it with an empty stored block␊ |
| that is three bits plus filler bits to the next byte, followed by four bytes␊ |
| (00 00 ff ff).␊ |
| ␊ |
| If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the␊ |
| output buffer, but the output is not aligned to a byte boundary. All of the␊ |
| input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.␊ |
| This completes the current deflate block and follows it with an empty fixed␊ |
| codes block that is 10 bits long. This assures that enough bytes are output␊ |
| in order for the decompressor to finish the block before the empty fixed code␊ |
| block.␊ |
| ␊ |
| If flush is set to Z_BLOCK, a deflate block is completed and emitted, as␊ |
| for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to␊ |
| seven bits of the current block are held to be written as the next byte after␊ |
| the next deflate block is completed. In this case, the decompressor may not␊ |
| be provided enough bits at this point in order to complete decompression of␊ |
| the data provided so far to the compressor. It may need to wait for the next␊ |
| block to be emitted. This is for advanced applications that need to control␊ |
| the emission of deflate blocks.␊ |
| ␊ |
| If flush is set to Z_FULL_FLUSH, all output is flushed as with␊ |
| Z_SYNC_FLUSH, and the compression state is reset so that decompression can␊ |
| restart from this point if previous compressed data has been damaged or if␊ |
| random access is desired. Using Z_FULL_FLUSH too often can seriously degrade␊ |
| compression.␊ |
| ␊ |
| If deflate returns with avail_out == 0, this function must be called again␊ |
| with the same value of the flush parameter and more output space (updated␊ |
| avail_out), until the flush is complete (deflate returns with non-zero␊ |
| avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that␊ |
| avail_out is greater than six to avoid repeated flush markers due to␊ |
| avail_out == 0 on return.␊ |
| ␊ |
| If the parameter flush is set to Z_FINISH, pending input is processed,␊ |
| pending output is flushed and deflate returns with Z_STREAM_END if there was␊ |
| enough output space; if deflate returns with Z_OK, this function must be␊ |
| called again with Z_FINISH and more output space (updated avail_out) but no␊ |
| more input data, until it returns with Z_STREAM_END or an error. After␊ |
| deflate has returned Z_STREAM_END, the only possible operations on the stream␊ |
| are deflateReset or deflateEnd.␊ |
| ␊ |
| Z_FINISH can be used immediately after deflateInit if all the compression␊ |
| is to be done in a single step. In this case, avail_out must be at least the␊ |
| value returned by deflateBound (see below). If deflate does not return␊ |
| Z_STREAM_END, then it must be called again as described above.␊ |
| ␊ |
| deflate() sets strm->adler to the adler32 checksum of all input read␊ |
| so far (that is, total_in bytes).␊ |
| ␊ |
| deflate() may update strm->data_type if it can make a good guess about␊ |
| the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered␊ |
| binary. This field is only for information purposes and does not affect the␊ |
| compression algorithm in any manner.␊ |
| ␊ |
| deflate() returns Z_OK if some progress has been made (more input␊ |
| processed or more output produced), Z_STREAM_END if all input has been␊ |
| consumed and all output has been produced (only when flush is set to␊ |
| Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example␊ |
| if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible␊ |
| (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not␊ |
| fatal, and deflate() can be called again with more input and more output␊ |
| space to continue compressing.␊ |
| */␊ |
| ␊ |
| ␊ |
| ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));␊ |
| /*␊ |
| All dynamically allocated data structures for this stream are freed.␊ |
| This function discards any unprocessed input and does not flush any pending␊ |
| output.␊ |
| ␊ |
| deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the␊ |
| stream state was inconsistent, Z_DATA_ERROR if the stream was freed␊ |
| prematurely (some input or output was discarded). In the error case, msg␊ |
| may be set but then points to a static string (which must not be␊ |
| deallocated).␊ |
| */␊ |
| ␊ |
| ␊ |
| /*␊ |
| ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));␊ |
| ␊ |
| Initializes the internal stream state for decompression. The fields␊ |
| next_in, avail_in, zalloc, zfree and opaque must be initialized before by␊ |
| the caller. If next_in is not Z_NULL and avail_in is large enough (the␊ |
| exact value depends on the compression method), inflateInit determines the␊ |
| compression method from the zlib header and allocates all data structures␊ |
| accordingly; otherwise the allocation will be deferred to the first call of␊ |
| inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to␊ |
| use default allocation functions.␊ |
| ␊ |
| inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough␊ |
| memory, Z_VERSION_ERROR if the zlib library version is incompatible with the␊ |
| version assumed by the caller, or Z_STREAM_ERROR if the parameters are␊ |
| invalid, such as a null pointer to the structure. msg is set to null if␊ |
| there is no error message. inflateInit does not perform any decompression␊ |
| apart from possibly reading the zlib header if present: actual decompression␊ |
| will be done by inflate(). (So next_in and avail_in may be modified, but␊ |
| next_out and avail_out are unused and unchanged.) The current implementation␊ |
| of inflateInit() does not process any header information -- that is deferred␊ |
| until inflate() is called.␊ |
| */␊ |
| ␊ |
| ␊ |
| ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));␊ |
| /*␊ |
| inflate decompresses as much data as possible, and stops when the input␊ |
| buffer becomes empty or the output buffer becomes full. It may introduce␊ |
| some output latency (reading input without producing any output) except when␊ |
| forced to flush.␊ |
| ␊ |
| The detailed semantics are as follows. inflate performs one or both of the␊ |
| following actions:␊ |
| ␊ |
| - Decompress more input starting at next_in and update next_in and avail_in␊ |
| accordingly. If not all input can be processed (because there is not␊ |
| enough room in the output buffer), next_in is updated and processing will␊ |
| resume at this point for the next call of inflate().␊ |
| ␊ |
| - Provide more output starting at next_out and update next_out and avail_out␊ |
| accordingly. inflate() provides as much output as possible, until there is␊ |
| no more input data or no more space in the output buffer (see below about␊ |
| the flush parameter).␊ |
| ␊ |
| Before the call of inflate(), the application should ensure that at least␊ |
| one of the actions is possible, by providing more input and/or consuming more␊ |
| output, and updating the next_* and avail_* values accordingly. The␊ |
| application can consume the uncompressed output when it wants, for example␊ |
| when the output buffer is full (avail_out == 0), or after each call of␊ |
| inflate(). If inflate returns Z_OK and with zero avail_out, it must be␊ |
| called again after making room in the output buffer because there might be␊ |
| more output pending.␊ |
| ␊ |
| The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,␊ |
| Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much␊ |
| output as possible to the output buffer. Z_BLOCK requests that inflate()␊ |
| stop if and when it gets to the next deflate block boundary. When decoding␊ |
| the zlib or gzip format, this will cause inflate() to return immediately␊ |
| after the header and before the first block. When doing a raw inflate,␊ |
| inflate() will go ahead and process the first block, and will return when it␊ |
| gets to the end of that block, or when it runs out of data.␊ |
| ␊ |
| The Z_BLOCK option assists in appending to or combining deflate streams.␊ |
| Also to assist in this, on return inflate() will set strm->data_type to the␊ |
| number of unused bits in the last byte taken from strm->next_in, plus 64 if␊ |
| inflate() is currently decoding the last block in the deflate stream, plus␊ |
| 128 if inflate() returned immediately after decoding an end-of-block code or␊ |
| decoding the complete header up to just before the first byte of the deflate␊ |
| stream. The end-of-block will not be indicated until all of the uncompressed␊ |
| data from that block has been written to strm->next_out. The number of␊ |
| unused bits may in general be greater than seven, except when bit 7 of␊ |
| data_type is set, in which case the number of unused bits will be less than␊ |
| eight. data_type is set as noted here every time inflate() returns for all␊ |
| flush options, and so can be used to determine the amount of currently␊ |
| consumed input in bits.␊ |
| ␊ |
| The Z_TREES option behaves as Z_BLOCK does, but it also returns when the␊ |
| end of each deflate block header is reached, before any actual data in that␊ |
| block is decoded. This allows the caller to determine the length of the␊ |
| deflate block header for later use in random access within a deflate block.␊ |
| 256 is added to the value of strm->data_type when inflate() returns␊ |
| immediately after reaching the end of the deflate block header.␊ |
| ␊ |
| inflate() should normally be called until it returns Z_STREAM_END or an␊ |
| error. However if all decompression is to be performed in a single step (a␊ |
| single call of inflate), the parameter flush should be set to Z_FINISH. In␊ |
| this case all pending input is processed and all pending output is flushed;␊ |
| avail_out must be large enough to hold all the uncompressed data. (The size␊ |
| of the uncompressed data may have been saved by the compressor for this␊ |
| purpose.) The next operation on this stream must be inflateEnd to deallocate␊ |
| the decompression state. The use of Z_FINISH is never required, but can be␊ |
| used to inform inflate that a faster approach may be used for the single␊ |
| inflate() call.␊ |
| ␊ |
| In this implementation, inflate() always flushes as much output as␊ |
| possible to the output buffer, and always uses the faster approach on the␊ |
| first call. So the only effect of the flush parameter in this implementation␊ |
| is on the return value of inflate(), as noted below, or when it returns early␊ |
| because Z_BLOCK or Z_TREES is used.␊ |
| ␊ |
| If a preset dictionary is needed after this call (see inflateSetDictionary␊ |
| below), inflate sets strm->adler to the adler32 checksum of the dictionary␊ |
| chosen by the compressor and returns Z_NEED_DICT; otherwise it sets␊ |
| strm->adler to the adler32 checksum of all output produced so far (that is,␊ |
| total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described␊ |
| below. At the end of the stream, inflate() checks that its computed adler32␊ |
| checksum is equal to that saved by the compressor and returns Z_STREAM_END␊ |
| only if the checksum is correct.␊ |
| ␊ |
| inflate() can decompress and check either zlib-wrapped or gzip-wrapped␊ |
| deflate data. The header type is detected automatically, if requested when␊ |
| initializing with inflateInit2(). Any information contained in the gzip␊ |
| header is not retained, so applications that need that information should␊ |
| instead use raw inflate, see inflateInit2() below, or inflateBack() and␊ |
| perform their own processing of the gzip header and trailer.␊ |
| ␊ |
| inflate() returns Z_OK if some progress has been made (more input processed␊ |
| or more output produced), Z_STREAM_END if the end of the compressed data has␊ |
| been reached and all uncompressed output has been produced, Z_NEED_DICT if a␊ |
| preset dictionary is needed at this point, Z_DATA_ERROR if the input data was␊ |
| corrupted (input stream not conforming to the zlib format or incorrect check␊ |
| value), Z_STREAM_ERROR if the stream structure was inconsistent (for example␊ |
| next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,␊ |
| Z_BUF_ERROR if no progress is possible or if there was not enough room in the␊ |
| output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and␊ |
| inflate() can be called again with more input and more output space to␊ |
| continue decompressing. If Z_DATA_ERROR is returned, the application may␊ |
| then call inflateSync() to look for a good compression block if a partial␊ |
| recovery of the data is desired.␊ |
| */␊ |
| ␊ |
| ␊ |
| ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));␊ |
| /*␊ |
| All dynamically allocated data structures for this stream are freed.␊ |
| This function discards any unprocessed input and does not flush any pending␊ |
| output.␊ |
| ␊ |
| inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state␊ |
| was inconsistent. In the error case, msg may be set but then points to a␊ |
| static string (which must not be deallocated).␊ |
| */␊ |
| ␊ |
| ␊ |
| /* Advanced functions */␊ |
| ␊ |
| /*␊ |
| The following functions are needed only in some special applications.␊ |
| */␊ |
| ␊ |
| /*␊ |
| ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,␊ |
| int level,␊ |
| int method,␊ |
| int windowBits,␊ |
| int memLevel,␊ |
| int strategy));␊ |
| ␊ |
| This is another version of deflateInit with more compression options. The␊ |
| fields next_in, zalloc, zfree and opaque must be initialized before by the␊ |
| caller.␊ |
| ␊ |
| The method parameter is the compression method. It must be Z_DEFLATED in␊ |
| this version of the library.␊ |
| ␊ |
| The windowBits parameter is the base two logarithm of the window size␊ |
| (the size of the history buffer). It should be in the range 8..15 for this␊ |
| version of the library. Larger values of this parameter result in better␊ |
| compression at the expense of memory usage. The default value is 15 if␊ |
| deflateInit is used instead.␊ |
| ␊ |
| windowBits can also be -8..-15 for raw deflate. In this case, -windowBits␊ |
| determines the window size. deflate() will then generate raw deflate data␊ |
| with no zlib header or trailer, and will not compute an adler32 check value.␊ |
| ␊ |
| windowBits can also be greater than 15 for optional gzip encoding. Add␊ |
| 16 to windowBits to write a simple gzip header and trailer around the␊ |
| compressed data instead of a zlib wrapper. The gzip header will have no␊ |
| file name, no extra data, no comment, no modification time (set to zero), no␊ |
| header crc, and the operating system will be set to 255 (unknown). If a␊ |
| gzip stream is being written, strm->adler is a crc32 instead of an adler32.␊ |
| ␊ |
| The memLevel parameter specifies how much memory should be allocated␊ |
| for the internal compression state. memLevel=1 uses minimum memory but is␊ |
| slow and reduces compression ratio; memLevel=9 uses maximum memory for␊ |
| optimal speed. The default value is 8. See zconf.h for total memory usage␊ |
| as a function of windowBits and memLevel.␊ |
| ␊ |
| The strategy parameter is used to tune the compression algorithm. Use the␊ |
| value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a␊ |
| filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no␊ |
| string match), or Z_RLE to limit match distances to one (run-length␊ |
| encoding). Filtered data consists mostly of small values with a somewhat␊ |
| random distribution. In this case, the compression algorithm is tuned to␊ |
| compress them better. The effect of Z_FILTERED is to force more Huffman␊ |
| coding and less string matching; it is somewhat intermediate between␊ |
| Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as␊ |
| fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The␊ |
| strategy parameter only affects the compression ratio but not the␊ |
| correctness of the compressed output even if it is not set appropriately.␊ |
| Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler␊ |
| decoder for special applications.␊ |
| ␊ |
| deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough␊ |
| memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid␊ |
| method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is␊ |
| incompatible with the version assumed by the caller (ZLIB_VERSION). msg is␊ |
| set to null if there is no error message. deflateInit2 does not perform any␊ |
| compression: this will be done by deflate().␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,␊ |
| const Bytef *dictionary,␊ |
| uInt dictLength));␊ |
| /*␊ |
| Initializes the compression dictionary from the given byte sequence␊ |
| without producing any compressed output. This function must be called␊ |
| immediately after deflateInit, deflateInit2 or deflateReset, before any call␊ |
| of deflate. The compressor and decompressor must use exactly the same␊ |
| dictionary (see inflateSetDictionary).␊ |
| ␊ |
| The dictionary should consist of strings (byte sequences) that are likely␊ |
| to be encountered later in the data to be compressed, with the most commonly␊ |
| used strings preferably put towards the end of the dictionary. Using a␊ |
| dictionary is most useful when the data to be compressed is short and can be␊ |
| predicted with good accuracy; the data can then be compressed better than␊ |
| with the default empty dictionary.␊ |
| ␊ |
| Depending on the size of the compression data structures selected by␊ |
| deflateInit or deflateInit2, a part of the dictionary may in effect be␊ |
| discarded, for example if the dictionary is larger than the window size␊ |
| provided in deflateInit or deflateInit2. Thus the strings most likely to be␊ |
| useful should be put at the end of the dictionary, not at the front. In␊ |
| addition, the current implementation of deflate will use at most the window␊ |
| size minus 262 bytes of the provided dictionary.␊ |
| ␊ |
| Upon return of this function, strm->adler is set to the adler32 value␊ |
| of the dictionary; the decompressor may later use this value to determine␊ |
| which dictionary has been used by the compressor. (The adler32 value␊ |
| applies to the whole dictionary even if only a subset of the dictionary is␊ |
| actually used by the compressor.) If a raw deflate was requested, then the␊ |
| adler32 value is not computed and strm->adler is not set.␊ |
| ␊ |
| deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a␊ |
| parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is␊ |
| inconsistent (for example if deflate has already been called for this stream␊ |
| or if the compression method is bsort). deflateSetDictionary does not␊ |
| perform any compression: this will be done by deflate().␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,␊ |
| z_streamp source));␊ |
| /*␊ |
| Sets the destination stream as a complete copy of the source stream.␊ |
| ␊ |
| This function can be useful when several compression strategies will be␊ |
| tried, for example when there are several ways of pre-processing the input␊ |
| data with a filter. The streams that will be discarded should then be freed␊ |
| by calling deflateEnd. Note that deflateCopy duplicates the internal␊ |
| compression state which can be quite large, so this strategy is slow and can␊ |
| consume lots of memory.␊ |
| ␊ |
| deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not␊ |
| enough memory, Z_STREAM_ERROR if the source stream state was inconsistent␊ |
| (such as zalloc being Z_NULL). msg is left unchanged in both source and␊ |
| destination.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));␊ |
| /*␊ |
| This function is equivalent to deflateEnd followed by deflateInit,␊ |
| but does not free and reallocate all the internal compression state. The␊ |
| stream will keep the same compression level and any other attributes that␊ |
| may have been set by deflateInit2.␊ |
| ␊ |
| deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source␊ |
| stream state was inconsistent (such as zalloc or state being Z_NULL).␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,␊ |
| int level,␊ |
| int strategy));␊ |
| /*␊ |
| Dynamically update the compression level and compression strategy. The␊ |
| interpretation of level and strategy is as in deflateInit2. This can be␊ |
| used to switch between compression and straight copy of the input data, or␊ |
| to switch to a different kind of input data requiring a different strategy.␊ |
| If the compression level is changed, the input available so far is␊ |
| compressed with the old level (and may be flushed); the new level will take␊ |
| effect only at the next call of deflate().␊ |
| ␊ |
| Before the call of deflateParams, the stream state must be set as for␊ |
| a call of deflate(), since the currently available input may have to be␊ |
| compressed and flushed. In particular, strm->avail_out must be non-zero.␊ |
| ␊ |
| deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source␊ |
| stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if␊ |
| strm->avail_out was zero.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,␊ |
| int good_length,␊ |
| int max_lazy,␊ |
| int nice_length,␊ |
| int max_chain));␊ |
| /*␊ |
| Fine tune deflate's internal compression parameters. This should only be␊ |
| used by someone who understands the algorithm used by zlib's deflate for␊ |
| searching for the best matching string, and even then only by the most␊ |
| fanatic optimizer trying to squeeze out the last compressed bit for their␊ |
| specific input data. Read the deflate.c source code for the meaning of the␊ |
| max_lazy, good_length, nice_length, and max_chain parameters.␊ |
| ␊ |
| deflateTune() can be called after deflateInit() or deflateInit2(), and␊ |
| returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.␊ |
| */␊ |
| ␊ |
| ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,␊ |
| uLong sourceLen));␊ |
| /*␊ |
| deflateBound() returns an upper bound on the compressed size after␊ |
| deflation of sourceLen bytes. It must be called after deflateInit() or␊ |
| deflateInit2(), and after deflateSetHeader(), if used. This would be used␊ |
| to allocate an output buffer for deflation in a single pass, and so would be␊ |
| called before deflate().␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,␊ |
| int bits,␊ |
| int value));␊ |
| /*␊ |
| deflatePrime() inserts bits in the deflate output stream. The intent␊ |
| is that this function is used to start off the deflate output with the bits␊ |
| leftover from a previous deflate stream when appending to it. As such, this␊ |
| function can only be used for raw deflate, and must be used before the first␊ |
| deflate() call after a deflateInit2() or deflateReset(). bits must be less␊ |
| than or equal to 16, and that many of the least significant bits of value␊ |
| will be inserted in the output.␊ |
| ␊ |
| deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source␊ |
| stream state was inconsistent.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,␊ |
| gz_headerp head));␊ |
| /*␊ |
| deflateSetHeader() provides gzip header information for when a gzip␊ |
| stream is requested by deflateInit2(). deflateSetHeader() may be called␊ |
| after deflateInit2() or deflateReset() and before the first call of␊ |
| deflate(). The text, time, os, extra field, name, and comment information␊ |
| in the provided gz_header structure are written to the gzip header (xflag is␊ |
| ignored -- the extra flags are set according to the compression level). The␊ |
| caller must assure that, if not Z_NULL, name and comment are terminated with␊ |
| a zero byte, and that if extra is not Z_NULL, that extra_len bytes are␊ |
| available there. If hcrc is true, a gzip header crc is included. Note that␊ |
| the current versions of the command-line version of gzip (up through version␊ |
| 1.3.x) do not support header crc's, and will report that it is a "multi-part␊ |
| gzip file" and give up.␊ |
| ␊ |
| If deflateSetHeader is not used, the default gzip header has text false,␊ |
| the time set to zero, and os set to 255, with no extra, name, or comment␊ |
| fields. The gzip header is returned to the default state by deflateReset().␊ |
| ␊ |
| deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source␊ |
| stream state was inconsistent.␊ |
| */␊ |
| ␊ |
| /*␊ |
| ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,␊ |
| int windowBits));␊ |
| ␊ |
| This is another version of inflateInit with an extra parameter. The␊ |
| fields next_in, avail_in, zalloc, zfree and opaque must be initialized␊ |
| before by the caller.␊ |
| ␊ |
| The windowBits parameter is the base two logarithm of the maximum window␊ |
| size (the size of the history buffer). It should be in the range 8..15 for␊ |
| this version of the library. The default value is 15 if inflateInit is used␊ |
| instead. windowBits must be greater than or equal to the windowBits value␊ |
| provided to deflateInit2() while compressing, or it must be equal to 15 if␊ |
| deflateInit2() was not used. If a compressed stream with a larger window␊ |
| size is given as input, inflate() will return with the error code␊ |
| Z_DATA_ERROR instead of trying to allocate a larger window.␊ |
| ␊ |
| windowBits can also be zero to request that inflate use the window size in␊ |
| the zlib header of the compressed stream.␊ |
| ␊ |
| windowBits can also be -8..-15 for raw inflate. In this case, -windowBits␊ |
| determines the window size. inflate() will then process raw deflate data,␊ |
| not looking for a zlib or gzip header, not generating a check value, and not␊ |
| looking for any check values for comparison at the end of the stream. This␊ |
| is for use with other formats that use the deflate compressed data format␊ |
| such as zip. Those formats provide their own check values. If a custom␊ |
| format is developed using the raw deflate format for compressed data, it is␊ |
| recommended that a check value such as an adler32 or a crc32 be applied to␊ |
| the uncompressed data as is done in the zlib, gzip, and zip formats. For␊ |
| most applications, the zlib format should be used as is. Note that comments␊ |
| above on the use in deflateInit2() applies to the magnitude of windowBits.␊ |
| ␊ |
| windowBits can also be greater than 15 for optional gzip decoding. Add␊ |
| 32 to windowBits to enable zlib and gzip decoding with automatic header␊ |
| detection, or add 16 to decode only the gzip format (the zlib format will␊ |
| return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a␊ |
| crc32 instead of an adler32.␊ |
| ␊ |
| inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough␊ |
| memory, Z_VERSION_ERROR if the zlib library version is incompatible with the␊ |
| version assumed by the caller, or Z_STREAM_ERROR if the parameters are␊ |
| invalid, such as a null pointer to the structure. msg is set to null if␊ |
| there is no error message. inflateInit2 does not perform any decompression␊ |
| apart from possibly reading the zlib header if present: actual decompression␊ |
| will be done by inflate(). (So next_in and avail_in may be modified, but␊ |
| next_out and avail_out are unused and unchanged.) The current implementation␊ |
| of inflateInit2() does not process any header information -- that is␊ |
| deferred until inflate() is called.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,␊ |
| const Bytef *dictionary,␊ |
| uInt dictLength));␊ |
| /*␊ |
| Initializes the decompression dictionary from the given uncompressed byte␊ |
| sequence. This function must be called immediately after a call of inflate,␊ |
| if that call returned Z_NEED_DICT. The dictionary chosen by the compressor␊ |
| can be determined from the adler32 value returned by that call of inflate.␊ |
| The compressor and decompressor must use exactly the same dictionary (see␊ |
| deflateSetDictionary). For raw inflate, this function can be called␊ |
| immediately after inflateInit2() or inflateReset() and before any call of␊ |
| inflate() to set the dictionary. The application must insure that the␊ |
| dictionary that was used for compression is provided.␊ |
| ␊ |
| inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a␊ |
| parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is␊ |
| inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the␊ |
| expected one (incorrect adler32 value). inflateSetDictionary does not␊ |
| perform any decompression: this will be done by subsequent calls of␊ |
| inflate().␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));␊ |
| /*␊ |
| Skips invalid compressed data until a full flush point (see above the␊ |
| description of deflate with Z_FULL_FLUSH) can be found, or until all␊ |
| available input is skipped. No output is provided.␊ |
| ␊ |
| inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR␊ |
| if no more input was provided, Z_DATA_ERROR if no flush point has been␊ |
| found, or Z_STREAM_ERROR if the stream structure was inconsistent. In the␊ |
| success case, the application may save the current current value of total_in␊ |
| which indicates where valid compressed data was found. In the error case,␊ |
| the application may repeatedly call inflateSync, providing more input each␊ |
| time, until success or end of the input data.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,␊ |
| z_streamp source));␊ |
| /*␊ |
| Sets the destination stream as a complete copy of the source stream.␊ |
| ␊ |
| This function can be useful when randomly accessing a large stream. The␊ |
| first pass through the stream can periodically record the inflate state,␊ |
| allowing restarting inflate at those points when randomly accessing the␊ |
| stream.␊ |
| ␊ |
| inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not␊ |
| enough memory, Z_STREAM_ERROR if the source stream state was inconsistent␊ |
| (such as zalloc being Z_NULL). msg is left unchanged in both source and␊ |
| destination.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));␊ |
| /*␊ |
| This function is equivalent to inflateEnd followed by inflateInit,␊ |
| but does not free and reallocate all the internal decompression state. The␊ |
| stream will keep attributes that may have been set by inflateInit2.␊ |
| ␊ |
| inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source␊ |
| stream state was inconsistent (such as zalloc or state being Z_NULL).␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,␊ |
| int windowBits));␊ |
| /*␊ |
| This function is the same as inflateReset, but it also permits changing␊ |
| the wrap and window size requests. The windowBits parameter is interpreted␊ |
| the same as it is for inflateInit2.␊ |
| ␊ |
| inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source␊ |
| stream state was inconsistent (such as zalloc or state being Z_NULL), or if␊ |
| the windowBits parameter is invalid.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,␊ |
| int bits,␊ |
| int value));␊ |
| /*␊ |
| This function inserts bits in the inflate input stream. The intent is␊ |
| that this function is used to start inflating at a bit position in the␊ |
| middle of a byte. The provided bits will be used before any bytes are used␊ |
| from next_in. This function should only be used with raw inflate, and␊ |
| should be used before the first inflate() call after inflateInit2() or␊ |
| inflateReset(). bits must be less than or equal to 16, and that many of the␊ |
| least significant bits of value will be inserted in the input.␊ |
| ␊ |
| If bits is negative, then the input stream bit buffer is emptied. Then␊ |
| inflatePrime() can be called again to put bits in the buffer. This is used␊ |
| to clear out bits leftover after feeding inflate a block description prior␊ |
| to feeding inflate codes.␊ |
| ␊ |
| inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source␊ |
| stream state was inconsistent.␊ |
| */␊ |
| ␊ |
| ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));␊ |
| /*␊ |
| This function returns two values, one in the lower 16 bits of the return␊ |
| value, and the other in the remaining upper bits, obtained by shifting the␊ |
| return value down 16 bits. If the upper value is -1 and the lower value is␊ |
| zero, then inflate() is currently decoding information outside of a block.␊ |
| If the upper value is -1 and the lower value is non-zero, then inflate is in␊ |
| the middle of a stored block, with the lower value equaling the number of␊ |
| bytes from the input remaining to copy. If the upper value is not -1, then␊ |
| it is the number of bits back from the current bit position in the input of␊ |
| the code (literal or length/distance pair) currently being processed. In␊ |
| that case the lower value is the number of bytes already emitted for that␊ |
| code.␊ |
| ␊ |
| A code is being processed if inflate is waiting for more input to complete␊ |
| decoding of the code, or if it has completed decoding but is waiting for␊ |
| more output space to write the literal or match data.␊ |
| ␊ |
| inflateMark() is used to mark locations in the input data for random␊ |
| access, which may be at bit positions, and to note those cases where the␊ |
| output of a code may span boundaries of random access blocks. The current␊ |
| location in the input stream can be determined from avail_in and data_type␊ |
| as noted in the description for the Z_BLOCK flush parameter for inflate.␊ |
| ␊ |
| inflateMark returns the value noted above or -1 << 16 if the provided␊ |
| source stream state was inconsistent.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,␊ |
| gz_headerp head));␊ |
| /*␊ |
| inflateGetHeader() requests that gzip header information be stored in the␊ |
| provided gz_header structure. inflateGetHeader() may be called after␊ |
| inflateInit2() or inflateReset(), and before the first call of inflate().␊ |
| As inflate() processes the gzip stream, head->done is zero until the header␊ |
| is completed, at which time head->done is set to one. If a zlib stream is␊ |
| being decoded, then head->done is set to -1 to indicate that there will be␊ |
| no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be␊ |
| used to force inflate() to return immediately after header processing is␊ |
| complete and before any actual data is decompressed.␊ |
| ␊ |
| The text, time, xflags, and os fields are filled in with the gzip header␊ |
| contents. hcrc is set to true if there is a header CRC. (The header CRC␊ |
| was valid if done is set to one.) If extra is not Z_NULL, then extra_max␊ |
| contains the maximum number of bytes to write to extra. Once done is true,␊ |
| extra_len contains the actual extra field length, and extra contains the␊ |
| extra field, or that field truncated if extra_max is less than extra_len.␊ |
| If name is not Z_NULL, then up to name_max characters are written there,␊ |
| terminated with a zero unless the length is greater than name_max. If␊ |
| comment is not Z_NULL, then up to comm_max characters are written there,␊ |
| terminated with a zero unless the length is greater than comm_max. When any␊ |
| of extra, name, or comment are not Z_NULL and the respective field is not␊ |
| present in the header, then that field is set to Z_NULL to signal its␊ |
| absence. This allows the use of deflateSetHeader() with the returned␊ |
| structure to duplicate the header. However if those fields are set to␊ |
| allocated memory, then the application will need to save those pointers␊ |
| elsewhere so that they can be eventually freed.␊ |
| ␊ |
| If inflateGetHeader is not used, then the header information is simply␊ |
| discarded. The header is always checked for validity, including the header␊ |
| CRC if present. inflateReset() will reset the process to discard the header␊ |
| information. The application would need to call inflateGetHeader() again to␊ |
| retrieve the header from the next gzip stream.␊ |
| ␊ |
| inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source␊ |
| stream state was inconsistent.␊ |
| */␊ |
| ␊ |
| /*␊ |
| ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,␊ |
| unsigned char FAR *window));␊ |
| ␊ |
| Initialize the internal stream state for decompression using inflateBack()␊ |
| calls. The fields zalloc, zfree and opaque in strm must be initialized␊ |
| before the call. If zalloc and zfree are Z_NULL, then the default library-␊ |
| derived memory allocation routines are used. windowBits is the base two␊ |
| logarithm of the window size, in the range 8..15. window is a caller␊ |
| supplied buffer of that size. Except for special applications where it is␊ |
| assured that deflate was used with small window sizes, windowBits must be 15␊ |
| and a 32K byte window must be supplied to be able to decompress general␊ |
| deflate streams.␊ |
| ␊ |
| See inflateBack() for the usage of these routines.␊ |
| ␊ |
| inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of␊ |
| the paramaters are invalid, Z_MEM_ERROR if the internal state could not be␊ |
| allocated, or Z_VERSION_ERROR if the version of the library does not match␊ |
| the version of the header file.␊ |
| */␊ |
| ␊ |
| typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *));␊ |
| typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));␊ |
| ␊ |
| ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,␊ |
| in_func in, void FAR *in_desc,␊ |
| out_func out, void FAR *out_desc));␊ |
| /*␊ |
| inflateBack() does a raw inflate with a single call using a call-back␊ |
| interface for input and output. This is more efficient than inflate() for␊ |
| file i/o applications in that it avoids copying between the output and the␊ |
| sliding window by simply making the window itself the output buffer. This␊ |
| function trusts the application to not change the output buffer passed by␊ |
| the output function, at least until inflateBack() returns.␊ |
| ␊ |
| inflateBackInit() must be called first to allocate the internal state␊ |
| and to initialize the state with the user-provided window buffer.␊ |
| inflateBack() may then be used multiple times to inflate a complete, raw␊ |
| deflate stream with each call. inflateBackEnd() is then called to free the␊ |
| allocated state.␊ |
| ␊ |
| A raw deflate stream is one with no zlib or gzip header or trailer.␊ |
| This routine would normally be used in a utility that reads zip or gzip␊ |
| files and writes out uncompressed files. The utility would decode the␊ |
| header and process the trailer on its own, hence this routine expects only␊ |
| the raw deflate stream to decompress. This is different from the normal␊ |
| behavior of inflate(), which expects either a zlib or gzip header and␊ |
| trailer around the deflate stream.␊ |
| ␊ |
| inflateBack() uses two subroutines supplied by the caller that are then␊ |
| called by inflateBack() for input and output. inflateBack() calls those␊ |
| routines until it reads a complete deflate stream and writes out all of the␊ |
| uncompressed data, or until it encounters an error. The function's␊ |
| parameters and return types are defined above in the in_func and out_func␊ |
| typedefs. inflateBack() will call in(in_desc, &buf) which should return the␊ |
| number of bytes of provided input, and a pointer to that input in buf. If␊ |
| there is no input available, in() must return zero--buf is ignored in that␊ |
| case--and inflateBack() will return a buffer error. inflateBack() will call␊ |
| out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()␊ |
| should return zero on success, or non-zero on failure. If out() returns␊ |
| non-zero, inflateBack() will return with an error. Neither in() nor out()␊ |
| are permitted to change the contents of the window provided to␊ |
| inflateBackInit(), which is also the buffer that out() uses to write from.␊ |
| The length written by out() will be at most the window size. Any non-zero␊ |
| amount of input may be provided by in().␊ |
| ␊ |
| For convenience, inflateBack() can be provided input on the first call by␊ |
| setting strm->next_in and strm->avail_in. If that input is exhausted, then␊ |
| in() will be called. Therefore strm->next_in must be initialized before␊ |
| calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called␊ |
| immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in␊ |
| must also be initialized, and then if strm->avail_in is not zero, input will␊ |
| initially be taken from strm->next_in[0 .. strm->avail_in - 1].␊ |
| ␊ |
| The in_desc and out_desc parameters of inflateBack() is passed as the␊ |
| first parameter of in() and out() respectively when they are called. These␊ |
| descriptors can be optionally used to pass any information that the caller-␊ |
| supplied in() and out() functions need to do their job.␊ |
| ␊ |
| On return, inflateBack() will set strm->next_in and strm->avail_in to␊ |
| pass back any unused input that was provided by the last in() call. The␊ |
| return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR␊ |
| if in() or out() returned an error, Z_DATA_ERROR if there was a format error␊ |
| in the deflate stream (in which case strm->msg is set to indicate the nature␊ |
| of the error), or Z_STREAM_ERROR if the stream was not properly initialized.␊ |
| In the case of Z_BUF_ERROR, an input or output error can be distinguished␊ |
| using strm->next_in which will be Z_NULL only if in() returned an error. If␊ |
| strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning␊ |
| non-zero. (in() will always be called before out(), so strm->next_in is␊ |
| assured to be defined if out() returns non-zero.) Note that inflateBack()␊ |
| cannot return Z_OK.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));␊ |
| /*␊ |
| All memory allocated by inflateBackInit() is freed.␊ |
| ␊ |
| inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream␊ |
| state was inconsistent.␊ |
| */␊ |
| ␊ |
| ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));␊ |
| /* Return flags indicating compile-time options.␊ |
| ␊ |
| Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:␊ |
| 1.0: size of uInt␊ |
| 3.2: size of uLong␊ |
| 5.4: size of voidpf (pointer)␊ |
| 7.6: size of z_off_t␊ |
| ␊ |
| Compiler, assembler, and debug options:␊ |
| 8: DEBUG␊ |
| 9: ASMV or ASMINF -- use ASM code␊ |
| 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention␊ |
| 11: 0 (reserved)␊ |
| ␊ |
| One-time table building (smaller code, but not thread-safe if true):␊ |
| 12: BUILDFIXED -- build static block decoding tables when needed␊ |
| 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed␊ |
| 14,15: 0 (reserved)␊ |
| ␊ |
| Library content (indicates missing functionality):␊ |
| 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking␊ |
| deflate code when not needed)␊ |
| 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect␊ |
| and decode gzip streams (to avoid linking crc code)␊ |
| 18-19: 0 (reserved)␊ |
| ␊ |
| Operation variations (changes in library functionality):␊ |
| 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate␊ |
| 21: FASTEST -- deflate algorithm with only one, lowest compression level␊ |
| 22,23: 0 (reserved)␊ |
| ␊ |
| The sprintf variant used by gzprintf (zero is best):␊ |
| 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format␊ |
| 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!␊ |
| 26: 0 = returns value, 1 = void -- 1 means inferred string length returned␊ |
| ␊ |
| Remainder:␊ |
| 27-31: 0 (reserved)␊ |
| */␊ |
| ␊ |
| ␊ |
| /* utility functions */␊ |
| ␊ |
| /*␊ |
| The following utility functions are implemented on top of the basic␊ |
| stream-oriented functions. To simplify the interface, some default options␊ |
| are assumed (compression level and memory usage, standard memory allocation␊ |
| functions). The source code of these utility functions can be modified if␊ |
| you need special options.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,␊ |
| const Bytef *source, uLong sourceLen));␊ |
| /*␊ |
| Compresses the source buffer into the destination buffer. sourceLen is␊ |
| the byte length of the source buffer. Upon entry, destLen is the total size␊ |
| of the destination buffer, which must be at least the value returned by␊ |
| compressBound(sourceLen). Upon exit, destLen is the actual size of the␊ |
| compressed buffer.␊ |
| ␊ |
| compress returns Z_OK if success, Z_MEM_ERROR if there was not␊ |
| enough memory, Z_BUF_ERROR if there was not enough room in the output␊ |
| buffer.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,␊ |
| const Bytef *source, uLong sourceLen,␊ |
| int level));␊ |
| /*␊ |
| Compresses the source buffer into the destination buffer. The level␊ |
| parameter has the same meaning as in deflateInit. sourceLen is the byte␊ |
| length of the source buffer. Upon entry, destLen is the total size of the␊ |
| destination buffer, which must be at least the value returned by␊ |
| compressBound(sourceLen). Upon exit, destLen is the actual size of the␊ |
| compressed buffer.␊ |
| ␊ |
| compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough␊ |
| memory, Z_BUF_ERROR if there was not enough room in the output buffer,␊ |
| Z_STREAM_ERROR if the level parameter is invalid.␊ |
| */␊ |
| ␊ |
| ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));␊ |
| /*␊ |
| compressBound() returns an upper bound on the compressed size after␊ |
| compress() or compress2() on sourceLen bytes. It would be used before a␊ |
| compress() or compress2() call to allocate the destination buffer.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,␊ |
| const Bytef *source, uLong sourceLen));␊ |
| /*␊ |
| Decompresses the source buffer into the destination buffer. sourceLen is␊ |
| the byte length of the source buffer. Upon entry, destLen is the total size␊ |
| of the destination buffer, which must be large enough to hold the entire␊ |
| uncompressed data. (The size of the uncompressed data must have been saved␊ |
| previously by the compressor and transmitted to the decompressor by some␊ |
| mechanism outside the scope of this compression library.) Upon exit, destLen␊ |
| is the actual size of the uncompressed buffer.␊ |
| ␊ |
| uncompress returns Z_OK if success, Z_MEM_ERROR if there was not␊ |
| enough memory, Z_BUF_ERROR if there was not enough room in the output␊ |
| buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.␊ |
| */␊ |
| ␊ |
| ␊ |
| /* gzip file access functions */␊ |
| ␊ |
| /*␊ |
| This library supports reading and writing files in gzip (.gz) format with␊ |
| an interface similar to that of stdio, using the functions that start with␊ |
| "gz". The gzip format is different from the zlib format. gzip is a gzip␊ |
| wrapper, documented in RFC 1952, wrapped around a deflate stream.␊ |
| */␊ |
| ␊ |
| typedef voidp gzFile; /* opaque gzip file descriptor */␊ |
| ␊ |
| /*␊ |
| ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));␊ |
| ␊ |
| Opens a gzip (.gz) file for reading or writing. The mode parameter is as␊ |
| in fopen ("rb" or "wb") but can also include a compression level ("wb9") or␊ |
| a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only␊ |
| compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'␊ |
| for fixed code compression as in "wb9F". (See the description of␊ |
| deflateInit2 for more information about the strategy parameter.) Also "a"␊ |
| can be used instead of "w" to request that the gzip stream that will be␊ |
| written be appended to the file. "+" will result in an error, since reading␊ |
| and writing to the same gzip file is not supported.␊ |
| ␊ |
| gzopen can be used to read a file which is not in gzip format; in this␊ |
| case gzread will directly read from the file without decompression.␊ |
| ␊ |
| gzopen returns NULL if the file could not be opened, if there was␊ |
| insufficient memory to allocate the gzFile state, or if an invalid mode was␊ |
| specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).␊ |
| errno can be checked to determine if the reason gzopen failed was that the␊ |
| file could not be opened.␊ |
| */␊ |
| ␊ |
| ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));␊ |
| /*␊ |
| gzdopen associates a gzFile with the file descriptor fd. File descriptors␊ |
| are obtained from calls like open, dup, creat, pipe or fileno (if the file␊ |
| has been previously opened with fopen). The mode parameter is as in gzopen.␊ |
| ␊ |
| The next call of gzclose on the returned gzFile will also close the file␊ |
| descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor␊ |
| fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,␊ |
| mode);. The duplicated descriptor should be saved to avoid a leak, since␊ |
| gzdopen does not close fd if it fails.␊ |
| ␊ |
| gzdopen returns NULL if there was insufficient memory to allocate the␊ |
| gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not␊ |
| provided, or '+' was provided), or if fd is -1. The file descriptor is not␊ |
| used until the next gz* read, write, seek, or close operation, so gzdopen␊ |
| will not detect if fd is invalid (unless fd is -1).␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));␊ |
| /*␊ |
| Set the internal buffer size used by this library's functions. The␊ |
| default buffer size is 8192 bytes. This function must be called after␊ |
| gzopen() or gzdopen(), and before any other calls that read or write the␊ |
| file. The buffer memory allocation is always deferred to the first read or␊ |
| write. Two buffers are allocated, either both of the specified size when␊ |
| writing, or one of the specified size and the other twice that size when␊ |
| reading. A larger buffer size of, for example, 64K or 128K bytes will␊ |
| noticeably increase the speed of decompression (reading).␊ |
| ␊ |
| The new buffer size also affects the maximum length for gzprintf().␊ |
| ␊ |
| gzbuffer() returns 0 on success, or -1 on failure, such as being called␊ |
| too late.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));␊ |
| /*␊ |
| Dynamically update the compression level or strategy. See the description␊ |
| of deflateInit2 for the meaning of these parameters.␊ |
| ␊ |
| gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not␊ |
| opened for writing.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));␊ |
| /*␊ |
| Reads the given number of uncompressed bytes from the compressed file. If␊ |
| the input file was not in gzip format, gzread copies the given number of␊ |
| bytes into the buffer.␊ |
| ␊ |
| After reaching the end of a gzip stream in the input, gzread will continue␊ |
| to read, looking for another gzip stream, or failing that, reading the rest␊ |
| of the input file directly without decompression. The entire input file␊ |
| will be read if gzread is called until it returns less than the requested␊ |
| len.␊ |
| ␊ |
| gzread returns the number of uncompressed bytes actually read, less than␊ |
| len for end of file, or -1 for error.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT gzwrite OF((gzFile file,␊ |
| voidpc buf, unsigned len));␊ |
| /*␊ |
| Writes the given number of uncompressed bytes into the compressed file.␊ |
| gzwrite returns the number of uncompressed bytes written or 0 in case of␊ |
| error.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...));␊ |
| /*␊ |
| Converts, formats, and writes the arguments to the compressed file under␊ |
| control of the format string, as in fprintf. gzprintf returns the number of␊ |
| uncompressed bytes actually written, or 0 in case of error. The number of␊ |
| uncompressed bytes written is limited to 8191, or one less than the buffer␊ |
| size given to gzbuffer(). The caller should assure that this limit is not␊ |
| exceeded. If it is exceeded, then gzprintf() will return an error (0) with␊ |
| nothing written. In this case, there may also be a buffer overflow with␊ |
| unpredictable consequences, which is possible only if zlib was compiled with␊ |
| the insecure functions sprintf() or vsprintf() because the secure snprintf()␊ |
| or vsnprintf() functions were not available. This can be determined using␊ |
| zlibCompileFlags().␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));␊ |
| /*␊ |
| Writes the given null-terminated string to the compressed file, excluding␊ |
| the terminating null character.␊ |
| ␊ |
| gzputs returns the number of characters written, or -1 in case of error.␊ |
| */␊ |
| ␊ |
| ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));␊ |
| /*␊ |
| Reads bytes from the compressed file until len-1 characters are read, or a␊ |
| newline character is read and transferred to buf, or an end-of-file␊ |
| condition is encountered. If any characters are read or if len == 1, the␊ |
| string is terminated with a null character. If no characters are read due␊ |
| to an end-of-file or len < 1, then the buffer is left untouched.␊ |
| ␊ |
| gzgets returns buf which is a null-terminated string, or it returns NULL␊ |
| for end-of-file or in case of error. If there was an error, the contents at␊ |
| buf are indeterminate.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));␊ |
| /*␊ |
| Writes c, converted to an unsigned char, into the compressed file. gzputc␊ |
| returns the value that was written, or -1 in case of error.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT gzgetc OF((gzFile file));␊ |
| /*␊ |
| Reads one byte from the compressed file. gzgetc returns this byte or -1␊ |
| in case of end of file or error.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));␊ |
| /*␊ |
| Push one character back onto the stream to be read as the first character␊ |
| on the next read. At least one character of push-back is allowed.␊ |
| gzungetc() returns the character pushed, or -1 on failure. gzungetc() will␊ |
| fail if c is -1, and may fail if a character has been pushed but not read␊ |
| yet. If gzungetc is used immediately after gzopen or gzdopen, at least the␊ |
| output buffer size of pushed characters is allowed. (See gzbuffer above.)␊ |
| The pushed character will be discarded if the stream is repositioned with␊ |
| gzseek() or gzrewind().␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));␊ |
| /*␊ |
| Flushes all pending output into the compressed file. The parameter flush␊ |
| is as in the deflate() function. The return value is the zlib error number␊ |
| (see function gzerror below). gzflush is only permitted when writing.␊ |
| ␊ |
| If the flush parameter is Z_FINISH, the remaining data is written and the␊ |
| gzip stream is completed in the output. If gzwrite() is called again, a new␊ |
| gzip stream will be started in the output. gzread() is able to read such␊ |
| concatented gzip streams.␊ |
| ␊ |
| gzflush should be called only when strictly necessary because it will␊ |
| degrade compression if called too often.␊ |
| */␊ |
| ␊ |
| /*␊ |
| ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,␊ |
| z_off_t offset, int whence));␊ |
| ␊ |
| Sets the starting position for the next gzread or gzwrite on the given␊ |
| compressed file. The offset represents a number of bytes in the␊ |
| uncompressed data stream. The whence parameter is defined as in lseek(2);␊ |
| the value SEEK_END is not supported.␊ |
| ␊ |
| If the file is opened for reading, this function is emulated but can be␊ |
| extremely slow. If the file is opened for writing, only forward seeks are␊ |
| supported; gzseek then compresses a sequence of zeroes up to the new␊ |
| starting position.␊ |
| ␊ |
| gzseek returns the resulting offset location as measured in bytes from␊ |
| the beginning of the uncompressed stream, or -1 in case of error, in␊ |
| particular if the file is opened for writing and the new starting position␊ |
| would be before the current position.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT gzrewind OF((gzFile file));␊ |
| /*␊ |
| Rewinds the given file. This function is supported only for reading.␊ |
| ␊ |
| gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)␊ |
| */␊ |
| ␊ |
| /*␊ |
| ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));␊ |
| ␊ |
| Returns the starting position for the next gzread or gzwrite on the given␊ |
| compressed file. This position represents a number of bytes in the␊ |
| uncompressed data stream, and is zero when starting, even if appending or␊ |
| reading a gzip stream from the middle of a file using gzdopen().␊ |
| ␊ |
| gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)␊ |
| */␊ |
| ␊ |
| /*␊ |
| ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));␊ |
| ␊ |
| Returns the current offset in the file being read or written. This offset␊ |
| includes the count of bytes that precede the gzip stream, for example when␊ |
| appending or when using gzdopen() for reading. When reading, the offset␊ |
| does not include as yet unused buffered input. This information can be used␊ |
| for a progress indicator. On error, gzoffset() returns -1.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT gzeof OF((gzFile file));␊ |
| /*␊ |
| Returns true (1) if the end-of-file indicator has been set while reading,␊ |
| false (0) otherwise. Note that the end-of-file indicator is set only if the␊ |
| read tried to go past the end of the input, but came up short. Therefore,␊ |
| just like feof(), gzeof() may return false even if there is no more data to␊ |
| read, in the event that the last read request was for the exact number of␊ |
| bytes remaining in the input file. This will happen if the input file size␊ |
| is an exact multiple of the buffer size.␊ |
| ␊ |
| If gzeof() returns true, then the read functions will return no more data,␊ |
| unless the end-of-file indicator is reset by gzclearerr() and the input file␊ |
| has grown since the previous end of file was detected.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT gzdirect OF((gzFile file));␊ |
| /*␊ |
| Returns true (1) if file is being copied directly while reading, or false␊ |
| (0) if file is a gzip stream being decompressed. This state can change from␊ |
| false to true while reading the input file if the end of a gzip stream is␊ |
| reached, but is followed by data that is not another gzip stream.␊ |
| ␊ |
| If the input file is empty, gzdirect() will return true, since the input␊ |
| does not contain a gzip stream.␊ |
| ␊ |
| If gzdirect() is used immediately after gzopen() or gzdopen() it will␊ |
| cause buffers to be allocated to allow reading the file to determine if it␊ |
| is a gzip file. Therefore if gzbuffer() is used, it should be called before␊ |
| gzdirect().␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT gzclose OF((gzFile file));␊ |
| /*␊ |
| Flushes all pending output if necessary, closes the compressed file and␊ |
| deallocates the (de)compression state. Note that once file is closed, you␊ |
| cannot call gzerror with file, since its structures have been deallocated.␊ |
| gzclose must not be called more than once on the same file, just as free␊ |
| must not be called more than once on the same allocation.␊ |
| ␊ |
| gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a␊ |
| file operation error, or Z_OK on success.␊ |
| */␊ |
| ␊ |
| ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));␊ |
| ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));␊ |
| /*␊ |
| Same as gzclose(), but gzclose_r() is only for use when reading, and␊ |
| gzclose_w() is only for use when writing or appending. The advantage to␊ |
| using these instead of gzclose() is that they avoid linking in zlib␊ |
| compression or decompression code that is not used when only reading or only␊ |
| writing respectively. If gzclose() is used, then both compression and␊ |
| decompression code will be included the application when linking to a static␊ |
| zlib library.␊ |
| */␊ |
| ␊ |
| ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));␊ |
| /*␊ |
| Returns the error message for the last error which occurred on the given␊ |
| compressed file. errnum is set to zlib error number. If an error occurred␊ |
| in the file system and not in the compression library, errnum is set to␊ |
| Z_ERRNO and the application may consult errno to get the exact error code.␊ |
| ␊ |
| The application must not modify the returned string. Future calls to␊ |
| this function may invalidate the previously returned string. If file is␊ |
| closed, then the string previously returned by gzerror will no longer be␊ |
| available.␊ |
| ␊ |
| gzerror() should be used to distinguish errors from end-of-file for those␊ |
| functions above that do not distinguish those cases in their return values.␊ |
| */␊ |
| ␊ |
| ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));␊ |
| /*␊ |
| Clears the error and end-of-file flags for file. This is analogous to the␊ |
| clearerr() function in stdio. This is useful for continuing to read a gzip␊ |
| file that is being written concurrently.␊ |
| */␊ |
| ␊ |
| ␊ |
| /* checksum functions */␊ |
| ␊ |
| /*␊ |
| These functions are not related to compression but are exported␊ |
| anyway because they might be useful in applications using the compression␊ |
| library.␊ |
| */␊ |
| ␊ |
| ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));␊ |
| /*␊ |
| Update a running Adler-32 checksum with the bytes buf[0..len-1] and␊ |
| return the updated checksum. If buf is Z_NULL, this function returns the␊ |
| required initial value for the checksum.␊ |
| ␊ |
| An Adler-32 checksum is almost as reliable as a CRC32 but can be computed␊ |
| much faster.␊ |
| ␊ |
| Usage example:␊ |
| ␊ |
| uLong adler = adler32(0L, Z_NULL, 0);␊ |
| ␊ |
| while (read_buffer(buffer, length) != EOF) {␊ |
| adler = adler32(adler, buffer, length);␊ |
| }␊ |
| if (adler != original_adler) error();␊ |
| */␊ |
| ␊ |
| /*␊ |
| ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,␊ |
| z_off_t len2));␊ |
| ␊ |
| Combine two Adler-32 checksums into one. For two sequences of bytes, seq1␊ |
| and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for␊ |
| each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of␊ |
| seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.␊ |
| */␊ |
| ␊ |
| ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));␊ |
| /*␊ |
| Update a running CRC-32 with the bytes buf[0..len-1] and return the␊ |
| updated CRC-32. If buf is Z_NULL, this function returns the required␊ |
| initial value for the for the crc. Pre- and post-conditioning (one's␊ |
| complement) is performed within this function so it shouldn't be done by the␊ |
| application.␊ |
| ␊ |
| Usage example:␊ |
| ␊ |
| uLong crc = crc32(0L, Z_NULL, 0);␊ |
| ␊ |
| while (read_buffer(buffer, length) != EOF) {␊ |
| crc = crc32(crc, buffer, length);␊ |
| }␊ |
| if (crc != original_crc) error();␊ |
| */␊ |
| ␊ |
| /*␊ |
| ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));␊ |
| ␊ |
| Combine two CRC-32 check values into one. For two sequences of bytes,␊ |
| seq1 and seq2 with lengths len1 and len2, CRC-32 check values were␊ |
| calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32␊ |
| check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and␊ |
| len2.␊ |
| */␊ |
| ␊ |
| ␊ |
| /* various hacks, don't look :) */␊ |
| ␊ |
| /* deflateInit and inflateInit are macros to allow checking the zlib version␊ |
| * and the compiler's view of z_stream:␊ |
| */␊ |
| ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,␊ |
| const char *version, int stream_size));␊ |
| ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,␊ |
| const char *version, int stream_size));␊ |
| ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,␊ |
| int windowBits, int memLevel,␊ |
| int strategy, const char *version,␊ |
| int stream_size));␊ |
| ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,␊ |
| const char *version, int stream_size));␊ |
| ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,␊ |
| unsigned char FAR *window,␊ |
| const char *version,␊ |
| int stream_size));␊ |
| #define deflateInit(strm, level) \␊ |
| deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))␊ |
| #define inflateInit(strm) \␊ |
| inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))␊ |
| #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \␊ |
| deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\␊ |
| (strategy), ZLIB_VERSION, sizeof(z_stream))␊ |
| #define inflateInit2(strm, windowBits) \␊ |
| inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))␊ |
| #define inflateBackInit(strm, windowBits, window) \␊ |
| inflateBackInit_((strm), (windowBits), (window), \␊ |
| ZLIB_VERSION, sizeof(z_stream))␊ |
| ␊ |
| /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or␊ |
| * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if␊ |
| * both are true, the application gets the *64 functions, and the regular␊ |
| * functions are changed to 64 bits) -- in case these are set on systems␊ |
| * without large file support, _LFS64_LARGEFILE must also be true␊ |
| */␊ |
| #if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0␊ |
| ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));␊ |
| ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));␊ |
| ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));␊ |
| ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));␊ |
| ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));␊ |
| ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));␊ |
| #endif␊ |
| ␊ |
| #if !defined(ZLIB_INTERNAL) && _FILE_OFFSET_BITS-0 == 64 && _LFS64_LARGEFILE-0␊ |
| # define gzopen gzopen64␊ |
| # define gzseek gzseek64␊ |
| # define gztell gztell64␊ |
| # define gzoffset gzoffset64␊ |
| # define adler32_combine adler32_combine64␊ |
| # define crc32_combine crc32_combine64␊ |
| # ifdef _LARGEFILE64_SOURCE␊ |
| ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));␊ |
| ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));␊ |
| ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));␊ |
| ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));␊ |
| ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));␊ |
| ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));␊ |
| # endif␊ |
| #else␊ |
| ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));␊ |
| ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));␊ |
| ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));␊ |
| ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));␊ |
| ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));␊ |
| ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));␊ |
| #endif␊ |
| ␊ |
| /* hack for buggy compilers */␊ |
| #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)␊ |
| struct internal_state {int dummy;};␊ |
| #endif␊ |
| ␊ |
| /* undocumented functions */␊ |
| ZEXTERN const char * ZEXPORT zError OF((int));␊ |
| ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));␊ |
| ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void));␊ |
| ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int));␊ |
| ␊ |
| #ifdef __cplusplus␊ |
| }␊ |
| #endif␊ |
| ␊ |
| #endif /* ZLIB_H */␊ |
