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fossil-scm / compat / zlib / zlib.h
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/* zlib.h -- interface of the 'zlib' general purpose compression library
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version 1.3.2, February 17th, 2026
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Copyright (C) 1995-2026 Jean-loup Gailly and Mark Adler
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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Jean-loup Gailly Mark Adler
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[email protected] [email protected]
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The data format used by the zlib library is described by RFCs (Request for
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Comments) 1950 to 1952 at https://datatracker.ietf.org/doc/html/rfc1950
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(zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
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*/
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#ifndef ZLIB_H
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#define ZLIB_H
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#ifdef ZLIB_BUILD
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# include <zconf.h>
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#else
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# include "zconf.h"
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#endif
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#ifdef __cplusplus
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extern "C" {
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#endif
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#define ZLIB_VERSION "1.3.2"
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#define ZLIB_VERNUM 0x1320
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#define ZLIB_VER_MAJOR 1
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#define ZLIB_VER_MINOR 3
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#define ZLIB_VER_REVISION 2
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#define ZLIB_VER_SUBREVISION 0
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/*
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The 'zlib' compression library provides in-memory compression and
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decompression functions, including integrity checks of the uncompressed data.
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This version of the library supports only one compression method (deflation)
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but other algorithms will be added later and will have the same stream
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interface.
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Compression can be done in a single step if the buffers are large enough,
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or can be done by repeated calls of the compression function. In the latter
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case, the application must provide more input and/or consume the output
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(providing more output space) before each call.
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The compressed data format used by default by the in-memory functions is
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the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
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around a deflate stream, which is itself documented in RFC 1951.
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The library also supports reading and writing files in gzip (.gz) format
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with an interface similar to that of stdio using the functions that start
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with "gz". The gzip format is different from the zlib format. gzip is a
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gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
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This library can optionally read and write gzip and raw deflate streams in
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memory as well.
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The zlib format was designed to be compact and fast for use in memory
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and on communications channels. The gzip format was designed for single-
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file compression on file systems, has a larger header than zlib to maintain
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directory information, and uses a different, slower check method than zlib.
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The library does not install any signal handler. The decoder checks
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the consistency of the compressed data, so the library should never crash
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even in the case of corrupted input.
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*/
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typedef voidpf (*alloc_func)(voidpf opaque, uInt items, uInt size);
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typedef void (*free_func)(voidpf opaque, voidpf address);
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struct internal_state;
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typedef struct z_stream_s {
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z_const Bytef *next_in; /* next input byte */
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uInt avail_in; /* number of bytes available at next_in */
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uLong total_in; /* total number of input bytes read so far */
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Bytef *next_out; /* next output byte will go here */
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uInt avail_out; /* remaining free space at next_out */
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uLong total_out; /* total number of bytes output so far */
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z_const char *msg; /* last error message, NULL if no error */
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struct internal_state FAR *state; /* not visible by applications */
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alloc_func zalloc; /* used to allocate the internal state */
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free_func zfree; /* used to free the internal state */
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voidpf opaque; /* private data object passed to zalloc and zfree */
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int data_type; /* best guess about the data type: binary or text
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for deflate, or the decoding state for inflate */
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uLong adler; /* Adler-32 or CRC-32 value of the uncompressed data */
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uLong reserved; /* reserved for future use */
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} z_stream;
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typedef z_stream FAR *z_streamp;
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/*
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gzip header information passed to and from zlib routines. See RFC 1952
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for more details on the meanings of these fields.
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*/
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typedef struct gz_header_s {
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int text; /* true if compressed data believed to be text */
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uLong time; /* modification time */
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int xflags; /* extra flags (not used when writing a gzip file) */
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int os; /* operating system */
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Bytef *extra; /* pointer to extra field or Z_NULL if none */
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uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
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uInt extra_max; /* space at extra (only when reading header) */
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Bytef *name; /* pointer to zero-terminated file name or Z_NULL */
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uInt name_max; /* space at name (only when reading header) */
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Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */
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uInt comm_max; /* space at comment (only when reading header) */
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int hcrc; /* true if there was or will be a header crc */
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int done; /* true when done reading gzip header (not used
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when writing a gzip file) */
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} gz_header;
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typedef gz_header FAR *gz_headerp;
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/*
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The application must update next_in and avail_in when avail_in has dropped
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to zero. It must update next_out and avail_out when avail_out has dropped
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to zero. The application must initialize zalloc, zfree and opaque before
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calling the init function. All other fields are set by the compression
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library and must not be updated by the application.
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The opaque value provided by the application will be passed as the first
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parameter for calls of zalloc and zfree. This can be useful for custom
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memory management. The compression library attaches no meaning to the
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opaque value.
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zalloc must return Z_NULL if there is not enough memory for the object.
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If zlib is used in a multi-threaded application, zalloc and zfree must be
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thread safe. In that case, zlib is thread-safe. When zalloc and zfree are
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Z_NULL on entry to the initialization function, they are set to internal
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routines that use the standard library functions malloc() and free().
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On 16-bit systems, the functions zalloc and zfree must be able to allocate
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exactly 65536 bytes, but will not be required to allocate more than this if
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the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers
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returned by zalloc for objects of exactly 65536 bytes *must* have their
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offset normalized to zero. The default allocation function provided by this
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library ensures this (see zutil.c). To reduce memory requirements and avoid
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any allocation of 64K objects, at the expense of compression ratio, compile
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the library with -DMAX_WBITS=14 (see zconf.h).
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The fields total_in and total_out can be used for statistics or progress
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reports. After compression, total_in holds the total size of the
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uncompressed data and may be saved for use by the decompressor (particularly
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if the decompressor wants to decompress everything in a single step).
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*/
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/* constants */
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#define Z_NO_FLUSH 0
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#define Z_PARTIAL_FLUSH 1
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#define Z_SYNC_FLUSH 2
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#define Z_FULL_FLUSH 3
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#define Z_FINISH 4
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#define Z_BLOCK 5
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#define Z_TREES 6
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/* Allowed flush values; see deflate() and inflate() below for details */
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#define Z_OK 0
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#define Z_STREAM_END 1
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#define Z_NEED_DICT 2
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#define Z_ERRNO (-1)
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#define Z_STREAM_ERROR (-2)
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#define Z_DATA_ERROR (-3)
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#define Z_MEM_ERROR (-4)
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#define Z_BUF_ERROR (-5)
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#define Z_VERSION_ERROR (-6)
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/* Return codes for the compression/decompression functions. Negative values
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* are errors, positive values are used for special but normal events.
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*/
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#define Z_NO_COMPRESSION 0
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#define Z_BEST_SPEED 1
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#define Z_BEST_COMPRESSION 9
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#define Z_DEFAULT_COMPRESSION (-1)
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/* compression levels */
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#define Z_FILTERED 1
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#define Z_HUFFMAN_ONLY 2
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#define Z_RLE 3
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#define Z_FIXED 4
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#define Z_DEFAULT_STRATEGY 0
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/* compression strategy; see deflateInit2() below for details */
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#define Z_BINARY 0
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#define Z_TEXT 1
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#define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
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#define Z_UNKNOWN 2
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/* Possible values of the data_type field for deflate() */
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#define Z_DEFLATED 8
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/* The deflate compression method (the only one supported in this version) */
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#define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
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#define zlib_version zlibVersion()
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/* for compatibility with versions < 1.0.2 */
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/* basic functions */
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ZEXTERN const char * ZEXPORT zlibVersion(void);
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/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
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If the first character differs, the library code actually used is not
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compatible with the zlib.h header file used by the application. This check
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is automatically made by deflateInit and inflateInit.
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*/
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/*
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ZEXTERN int ZEXPORT deflateInit(z_streamp strm, int level);
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Initializes the internal stream state for compression. The fields
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zalloc, zfree and opaque must be initialized before by the caller. If
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zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
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allocation functions. total_in, total_out, adler, and msg are initialized.
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The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
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1 gives best speed, 9 gives best compression, 0 gives no compression at all
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(the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
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requests a default compromise between speed and compression (currently
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equivalent to level 6).
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deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
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memory, Z_STREAM_ERROR if level is not a valid compression level, or
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Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
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with the version assumed by the caller (ZLIB_VERSION). msg is set to null
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if there is no error message. deflateInit does not perform any compression:
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this will be done by deflate().
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*/
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ZEXTERN int ZEXPORT deflate(z_streamp strm, int flush);
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/*
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deflate compresses as much data as possible, and stops when the input
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buffer becomes empty or the output buffer becomes full. It may introduce
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some output latency (reading input without producing any output) except when
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forced to flush.
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The detailed semantics are as follows. deflate performs one or both of the
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following actions:
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- Compress more input starting at next_in and update next_in and avail_in
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accordingly. If not all input can be processed (because there is not
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enough room in the output buffer), next_in and avail_in are updated and
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processing will resume at this point for the next call of deflate().
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- Generate more output starting at next_out and update next_out and avail_out
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accordingly. This action is forced if the parameter flush is non zero.
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Forcing flush frequently degrades the compression ratio, so this parameter
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should be set only when necessary. Some output may be provided even if
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flush is zero.
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Before the call of deflate(), the application should ensure that at least
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one of the actions is possible, by providing more input and/or consuming more
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output, and updating avail_in or avail_out accordingly; avail_out should
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never be zero before the call. The application can consume the compressed
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output when it wants, for example when the output buffer is full (avail_out
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== 0), or after each call of deflate(). If deflate returns Z_OK and with
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zero avail_out, it must be called again after making room in the output
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buffer because there might be more output pending. See deflatePending(),
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which can be used if desired to determine whether or not there is more output
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in that case.
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Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
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decide how much data to accumulate before producing output, in order to
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maximize compression.
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If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
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flushed to the output buffer and the output is aligned on a byte boundary, so
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that the decompressor can get all input data available so far. (In
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particular avail_in is zero after the call if enough output space has been
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provided before the call.) Flushing may degrade compression for some
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compression algorithms and so it should be used only when necessary. This
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completes the current deflate block and follows it with an empty stored block
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that is three bits plus filler bits to the next byte, followed by four bytes
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(00 00 ff ff).
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If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
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output buffer, but the output is not aligned to a byte boundary. All of the
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input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
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This completes the current deflate block and follows it with an empty fixed
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codes block that is 10 bits long. This assures that enough bytes are output
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in order for the decompressor to finish the block before the empty fixed
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codes block.
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If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
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for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
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seven bits of the current block are held to be written as the next byte after
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the next deflate block is completed. In this case, the decompressor may not
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be provided enough bits at this point in order to complete decompression of
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the data provided so far to the compressor. It may need to wait for the next
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block to be emitted. This is for advanced applications that need to control
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the emission of deflate blocks.
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If flush is set to Z_FULL_FLUSH, all output is flushed as with
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Z_SYNC_FLUSH, and the compression state is reset so that decompression can
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restart from this point if previous compressed data has been damaged or if
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random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
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compression.
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If deflate returns with avail_out == 0, this function must be called again
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with the same value of the flush parameter and more output space (updated
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avail_out), until the flush is complete (deflate returns with non-zero
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avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
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avail_out is greater than six when the flush marker begins, in order to avoid
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repeated flush markers upon calling deflate() again when avail_out == 0.
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If the parameter flush is set to Z_FINISH, pending input is processed,
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pending output is flushed and deflate returns with Z_STREAM_END if there was
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enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this
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function must be called again with Z_FINISH and more output space (updated
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avail_out) but no more input data, until it returns with Z_STREAM_END or an
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error. After deflate has returned Z_STREAM_END, the only possible operations
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on the stream are deflateReset or deflateEnd.
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Z_FINISH can be used in the first deflate call after deflateInit if all the
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compression is to be done in a single step. In order to complete in one
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call, avail_out must be at least the value returned by deflateBound (see
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below). Then deflate is guaranteed to return Z_STREAM_END. If not enough
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output space is provided, deflate will not return Z_STREAM_END, and it must
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be called again as described above.
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deflate() sets strm->adler to the Adler-32 checksum of all input read
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so far (that is, total_in bytes). If a gzip stream is being generated, then
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strm->adler will be the CRC-32 checksum of the input read so far. (See
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deflateInit2 below.)
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deflate() may update strm->data_type if it can make a good guess about
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the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is
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considered binary. This field is only for information purposes and does not
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affect the compression algorithm in any manner.
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deflate() returns Z_OK if some progress has been made (more input
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processed or more output produced), Z_STREAM_END if all input has been
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consumed and all output has been produced (only when flush is set to
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Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
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if next_in or next_out was Z_NULL or the state was inadvertently written over
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by the application), or Z_BUF_ERROR if no progress is possible (for example
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avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and
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deflate() can be called again with more input and more output space to
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continue compressing.
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*/
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ZEXTERN int ZEXPORT deflateEnd(z_streamp strm);
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/*
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All dynamically allocated data structures for this stream are freed.
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This function discards any unprocessed input and does not flush any pending
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output.
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deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
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stream state was inconsistent, Z_DATA_ERROR if the stream was freed
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prematurely (some input or output was discarded). In the error case, msg
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may be set but then points to a static string (which must not be
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deallocated).
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*/
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/*
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ZEXTERN int ZEXPORT inflateInit(z_streamp strm);
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Initializes the internal stream state for decompression. The fields
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next_in, avail_in, zalloc, zfree and opaque must be initialized before by
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the caller. In the current version of inflate, the provided input is not
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read or consumed. The allocation of a sliding window will be deferred to
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the first call of inflate (if the decompression does not complete on the
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first call). If zalloc and zfree are set to Z_NULL, inflateInit updates
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them to use default allocation functions. total_in, total_out, adler, and
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msg are initialized.
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inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
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memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
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version assumed by the caller, or Z_STREAM_ERROR if the parameters are
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invalid, such as a null pointer to the structure. msg is set to null if
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there is no error message. inflateInit does not perform any decompression.
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Actual decompression will be done by inflate(). So next_in, and avail_in,
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next_out, and avail_out are unused and unchanged. The current
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implementation of inflateInit() does not process any header information --
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that is deferred until inflate() is called.
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*/
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ZEXTERN int ZEXPORT inflate(z_streamp strm, int flush);
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/*
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inflate decompresses as much data as possible, and stops when the input
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buffer becomes empty or the output buffer becomes full. It may introduce
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some output latency (reading input without producing any output) except when
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forced to flush.
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The detailed semantics are as follows. inflate performs one or both of the
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following actions:
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- Decompress more input starting at next_in and update next_in and avail_in
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accordingly. If not all input can be processed (because there is not
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enough room in the output buffer), then next_in and avail_in are updated
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accordingly, and processing will resume at this point for the next call of
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inflate().
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- Generate more output starting at next_out and update next_out and avail_out
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accordingly. inflate() provides as much output as possible, until there is
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no more input data or no more space in the output buffer (see below about
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the flush parameter).
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Before the call of inflate(), the application should ensure that at least
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one of the actions is possible, by providing more input and/or consuming more
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output, and updating the next_* and avail_* values accordingly. If the
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caller of inflate() does not provide both available input and available
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output space, it is possible that there will be no progress made. The
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application can consume the uncompressed output when it wants, for example
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when the output buffer is full (avail_out == 0), or after each call of
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inflate(). If inflate returns Z_OK and with zero avail_out, it must be
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called again after making room in the output buffer because there might be
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more output pending.
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The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
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Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
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output as possible to the output buffer. Z_BLOCK requests that inflate()
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stop if and when it gets to the next deflate block boundary. When decoding
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the zlib or gzip format, this will cause inflate() to return immediately
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after the header and before the first block. When doing a raw inflate,
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inflate() will go ahead and process the first block, and will return when it
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gets to the end of that block, or when it runs out of data.
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The Z_BLOCK option assists in appending to or combining deflate streams.
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To assist in this, on return inflate() always sets strm->data_type to the
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number of unused bits in the input taken from strm->next_in, plus 64 if
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inflate() is currently decoding the last block in the deflate stream, plus
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128 if inflate() returned immediately after decoding an end-of-block code or
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decoding the complete header up to just before the first byte of the deflate
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stream. The end-of-block will not be indicated until all of the uncompressed
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data from that block has been written to strm->next_out. The number of
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unused bits may in general be greater than seven, except when bit 7 of
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data_type is set, in which case the number of unused bits will be less than
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eight. data_type is set as noted here every time inflate() returns for all
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flush options, and so can be used to determine the amount of currently
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consumed input in bits.
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The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
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end of each deflate block header is reached, before any actual data in that
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block is decoded. This allows the caller to determine the length of the
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deflate block header for later use in random access within a deflate block.
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256 is added to the value of strm->data_type when inflate() returns
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immediately after reaching the end of the deflate block header.
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inflate() should normally be called until it returns Z_STREAM_END or an
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error. However if all decompression is to be performed in a single step (a
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single call of inflate), the parameter flush should be set to Z_FINISH. In
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this case all pending input is processed and all pending output is flushed;
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avail_out must be large enough to hold all of the uncompressed data for the
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operation to complete. (The size of the uncompressed data may have been
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saved by the compressor for this purpose.) The use of Z_FINISH is not
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required to perform an inflation in one step. However it may be used to
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inform inflate that a faster approach can be used for the single inflate()
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call. Z_FINISH also informs inflate to not maintain a sliding window if the
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stream completes, which reduces inflate's memory footprint. If the stream
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does not complete, either because not all of the stream is provided or not
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enough output space is provided, then a sliding window will be allocated and
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inflate() can be called again to continue the operation as if Z_NO_FLUSH had
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been used.
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In this implementation, inflate() always flushes as much output as
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possible to the output buffer, and always uses the faster approach on the
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first call. So the effects of the flush parameter in this implementation are
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on the return value of inflate() as noted below, when inflate() returns early
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when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
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memory for a sliding window when Z_FINISH is used.
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If a preset dictionary is needed after this call (see inflateSetDictionary
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below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
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chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
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strm->adler to the Adler-32 checksum of all output produced so far (that is,
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total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
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below. At the end of the stream, inflate() checks that its computed Adler-32
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checksum is equal to that saved by the compressor and returns Z_STREAM_END
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only if the checksum is correct.
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inflate() can decompress and check either zlib-wrapped or gzip-wrapped
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deflate data. The header type is detected automatically, if requested when
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initializing with inflateInit2(). Any information contained in the gzip
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header is not retained unless inflateGetHeader() is used. When processing
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gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
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produced so far. The CRC-32 is checked against the gzip trailer, as is the
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uncompressed length, modulo 2^32.
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inflate() returns Z_OK if some progress has been made (more input processed
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or more output produced), Z_STREAM_END if the end of the compressed data has
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been reached and all uncompressed output has been produced, Z_NEED_DICT if a
510
preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
511
corrupted (input stream not conforming to the zlib format or incorrect check
512
value, in which case strm->msg points to a string with a more specific
513
error), Z_STREAM_ERROR if the stream structure was inconsistent (for example
514
next_in or next_out was Z_NULL, or the state was inadvertently written over
515
by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR
516
if no progress was possible or if there was not enough room in the output
517
buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
518
inflate() can be called again with more input and more output space to
519
continue decompressing. If Z_DATA_ERROR is returned, the application may
520
then call inflateSync() to look for a good compression block if a partial
521
recovery of the data is to be attempted.
522
*/
523
524
525
ZEXTERN int ZEXPORT inflateEnd(z_streamp strm);
526
/*
527
All dynamically allocated data structures for this stream are freed.
528
This function discards any unprocessed input and does not flush any pending
529
output.
530
531
inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state
532
was inconsistent.
533
*/
534
535
536
/* Advanced functions */
537
538
/*
539
The following functions are needed only in some special applications.
540
*/
541
542
/*
543
ZEXTERN int ZEXPORT deflateInit2(z_streamp strm,
544
int level,
545
int method,
546
int windowBits,
547
int memLevel,
548
int strategy);
549
550
This is another version of deflateInit with more compression options. The
551
fields zalloc, zfree and opaque must be initialized before by the caller.
552
553
The method parameter is the compression method. It must be Z_DEFLATED in
554
this version of the library.
555
556
The windowBits parameter is the base two logarithm of the window size
557
(the size of the history buffer). It should be in the range 8..15 for this
558
version of the library. Larger values of this parameter result in better
559
compression at the expense of memory usage. The default value is 15 if
560
deflateInit is used instead.
561
562
For the current implementation of deflate(), a windowBits value of 8 (a
563
window size of 256 bytes) is not supported. As a result, a request for 8
564
will result in 9 (a 512-byte window). In that case, providing 8 to
565
inflateInit2() will result in an error when the zlib header with 9 is
566
checked against the initialization of inflate(). The remedy is to not use 8
567
with deflateInit2() with this initialization, or at least in that case use 9
568
with inflateInit2().
569
570
windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
571
determines the window size. deflate() will then generate raw deflate data
572
with no zlib header or trailer, and will not compute a check value.
573
574
windowBits can also be greater than 15 for optional gzip encoding. Add
575
16 to windowBits to write a simple gzip header and trailer around the
576
compressed data instead of a zlib wrapper. The gzip header will have no
577
file name, no extra data, no comment, no modification time (set to zero), no
578
header crc, and the operating system will be set to the appropriate value,
579
if the operating system was determined at compile time. If a gzip stream is
580
being written, strm->adler is a CRC-32 instead of an Adler-32.
581
582
For raw deflate or gzip encoding, a request for a 256-byte window is
583
rejected as invalid, since only the zlib header provides a means of
584
transmitting the window size to the decompressor.
585
586
The memLevel parameter specifies how much memory should be allocated
587
for the internal compression state. memLevel=1 uses minimum memory but is
588
slow and reduces compression ratio; memLevel=9 uses maximum memory for
589
optimal speed. The default value is 8. See zconf.h for total memory usage
590
as a function of windowBits and memLevel.
591
592
The strategy parameter is used to tune the compression algorithm. Use the
593
value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
594
filter (or predictor), Z_RLE to limit match distances to one (run-length
595
encoding), or Z_HUFFMAN_ONLY to force Huffman encoding only (no string
596
matching). Filtered data consists mostly of small values with a somewhat
597
random distribution, as produced by the PNG filters. In this case, the
598
compression algorithm is tuned to compress them better. The effect of
599
Z_FILTERED is to force more Huffman coding and less string matching than the
600
default; it is intermediate between Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY.
601
Z_RLE is almost as fast as Z_HUFFMAN_ONLY, but should give better
602
compression for PNG image data than Huffman only. The degree of string
603
matching from most to none is: Z_DEFAULT_STRATEGY, Z_FILTERED, Z_RLE, then
604
Z_HUFFMAN_ONLY. The strategy parameter affects the compression ratio but
605
never the correctness of the compressed output, even if it is not set
606
optimally for the given data. Z_FIXED uses the default string matching, but
607
prevents the use of dynamic Huffman codes, allowing for a simpler decoder
608
for special applications.
609
610
deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
611
memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
612
method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
613
incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
614
set to null if there is no error message. deflateInit2 does not perform any
615
compression: this will be done by deflate().
616
*/
617
618
ZEXTERN int ZEXPORT deflateSetDictionary(z_streamp strm,
619
const Bytef *dictionary,
620
uInt dictLength);
621
/*
622
Initializes the compression dictionary from the given byte sequence
623
without producing any compressed output. When using the zlib format, this
624
function must be called immediately after deflateInit, deflateInit2 or
625
deflateReset, and before any call of deflate. When doing raw deflate, this
626
function must be called either before any call of deflate, or immediately
627
after the completion of a deflate block, i.e. after all input has been
628
consumed and all output has been delivered when using any of the flush
629
options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
630
compressor and decompressor must use exactly the same dictionary (see
631
inflateSetDictionary).
632
633
The dictionary should consist of strings (byte sequences) that are likely
634
to be encountered later in the data to be compressed, with the most commonly
635
used strings preferably put towards the end of the dictionary. Using a
636
dictionary is most useful when the data to be compressed is short and can be
637
predicted with good accuracy; the data can then be compressed better than
638
with the default empty dictionary.
639
640
Depending on the size of the compression data structures selected by
641
deflateInit or deflateInit2, a part of the dictionary may in effect be
642
discarded, for example if the dictionary is larger than the window size
643
provided in deflateInit or deflateInit2. Thus the strings most likely to be
644
useful should be put at the end of the dictionary, not at the front. In
645
addition, the current implementation of deflate will use at most the window
646
size minus 262 bytes of the provided dictionary.
647
648
Upon return of this function, strm->adler is set to the Adler-32 value
649
of the dictionary; the decompressor may later use this value to determine
650
which dictionary has been used by the compressor. (The Adler-32 value
651
applies to the whole dictionary even if only a subset of the dictionary is
652
actually used by the compressor.) If a raw deflate was requested, then the
653
Adler-32 value is not computed and strm->adler is not set.
654
655
deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
656
parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
657
inconsistent (for example if deflate has already been called for this stream
658
or if not at a block boundary for raw deflate). deflateSetDictionary does
659
not perform any compression: this will be done by deflate().
660
*/
661
662
ZEXTERN int ZEXPORT deflateGetDictionary(z_streamp strm,
663
Bytef *dictionary,
664
uInt *dictLength);
665
/*
666
Returns the sliding dictionary being maintained by deflate. dictLength is
667
set to the number of bytes in the dictionary, and that many bytes are copied
668
to dictionary. dictionary must have enough space, where 32768 bytes is
669
always enough. If deflateGetDictionary() is called with dictionary equal to
670
Z_NULL, then only the dictionary length is returned, and nothing is copied.
671
Similarly, if dictLength is Z_NULL, then it is not set.
672
673
deflateGetDictionary() may return a length less than the window size, even
674
when more than the window size in input has been provided. It may return up
675
to 258 bytes less in that case, due to how zlib's implementation of deflate
676
manages the sliding window and lookahead for matches, where matches can be
677
up to 258 bytes long. If the application needs the last window-size bytes of
678
input, then that would need to be saved by the application outside of zlib.
679
680
deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
681
stream state is inconsistent.
682
*/
683
684
ZEXTERN int ZEXPORT deflateCopy(z_streamp dest,
685
z_streamp source);
686
/*
687
Sets the destination stream as a complete copy of the source stream.
688
689
This function can be useful when several compression strategies will be
690
tried, for example when there are several ways of pre-processing the input
691
data with a filter. The streams that will be discarded should then be freed
692
by calling deflateEnd. Note that deflateCopy duplicates the internal
693
compression state which can be quite large, so this strategy is slow and can
694
consume lots of memory.
695
696
deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
697
enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
698
(such as zalloc being Z_NULL). msg is left unchanged in both source and
699
destination.
700
*/
701
702
ZEXTERN int ZEXPORT deflateReset(z_streamp strm);
703
/*
704
This function is equivalent to deflateEnd followed by deflateInit, but
705
does not free and reallocate the internal compression state. The stream
706
will leave the compression level and any other attributes that may have been
707
set unchanged. total_in, total_out, adler, and msg are initialized.
708
709
deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
710
stream state was inconsistent (such as zalloc or state being Z_NULL).
711
*/
712
713
ZEXTERN int ZEXPORT deflateParams(z_streamp strm,
714
int level,
715
int strategy);
716
/*
717
Dynamically update the compression level and compression strategy. The
718
interpretation of level and strategy is as in deflateInit2(). This can be
719
used to switch between compression and straight copy of the input data, or
720
to switch to a different kind of input data requiring a different strategy.
721
If the compression approach (which is a function of the level) or the
722
strategy is changed, and if there have been any deflate() calls since the
723
state was initialized or reset, then the input available so far is
724
compressed with the old level and strategy using deflate(strm, Z_BLOCK).
725
There are three approaches for the compression levels 0, 1..3, and 4..9
726
respectively. The new level and strategy will take effect at the next call
727
of deflate().
728
729
If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does
730
not have enough output space to complete, then the parameter change will not
731
take effect. In this case, deflateParams() can be called again with the
732
same parameters and more output space to try again.
733
734
In order to assure a change in the parameters on the first try, the
735
deflate stream should be flushed using deflate() with Z_BLOCK or other flush
736
request until strm.avail_out is not zero, before calling deflateParams().
737
Then no more input data should be provided before the deflateParams() call.
738
If this is done, the old level and strategy will be applied to the data
739
compressed before deflateParams(), and the new level and strategy will be
740
applied to the data compressed after deflateParams().
741
742
deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream
743
state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if
744
there was not enough output space to complete the compression of the
745
available input data before a change in the strategy or approach. Note that
746
in the case of a Z_BUF_ERROR, the parameters are not changed. A return
747
value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be
748
retried with more output space.
749
*/
750
751
ZEXTERN int ZEXPORT deflateTune(z_streamp strm,
752
int good_length,
753
int max_lazy,
754
int nice_length,
755
int max_chain);
756
/*
757
Fine tune deflate's internal compression parameters. This should only be
758
used by someone who understands the algorithm used by zlib's deflate for
759
searching for the best matching string, and even then only by the most
760
fanatic optimizer trying to squeeze out the last compressed bit for their
761
specific input data. Read the deflate.c source code for the meaning of the
762
max_lazy, good_length, nice_length, and max_chain parameters.
763
764
deflateTune() can be called after deflateInit() or deflateInit2(), and
765
returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
766
*/
767
768
ZEXTERN uLong ZEXPORT deflateBound(z_streamp strm, uLong sourceLen);
769
ZEXTERN z_size_t ZEXPORT deflateBound_z(z_streamp strm, z_size_t sourceLen);
770
/*
771
deflateBound() returns an upper bound on the compressed size after
772
deflation of sourceLen bytes. It must be called after deflateInit() or
773
deflateInit2(), and after deflateSetHeader(), if used. This would be used
774
to allocate an output buffer for deflation in a single pass, and so would be
775
called before deflate(). If that first deflate() call is provided the
776
sourceLen input bytes, an output buffer allocated to the size returned by
777
deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
778
to return Z_STREAM_END. Note that it is possible for the compressed size to
779
be larger than the value returned by deflateBound() if flush options other
780
than Z_FINISH or Z_NO_FLUSH are used.
781
782
delfateBound_z() is the same, but takes and returns a size_t length. Note
783
that a long is 32 bits on Windows.
784
*/
785
786
ZEXTERN int ZEXPORT deflatePending(z_streamp strm,
787
unsigned *pending,
788
int *bits);
789
/*
790
deflatePending() returns the number of bytes and bits of output that have
791
been generated, but not yet provided in the available output. The bytes not
792
provided would be due to the available output space having being consumed.
793
The number of bits of output not provided are between 0 and 7, where they
794
await more bits to join them in order to fill out a full byte. If pending
795
or bits are Z_NULL, then those values are not set.
796
797
deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
798
stream state was inconsistent. If an int is 16 bits and memLevel is 9, then
799
it is possible for the number of pending bytes to not fit in an unsigned. In
800
that case Z_BUF_ERROR is returned and *pending is set to the maximum value
801
of an unsigned.
802
*/
803
804
ZEXTERN int ZEXPORT deflateUsed(z_streamp strm,
805
int *bits);
806
/*
807
deflateUsed() returns in *bits the most recent number of deflate bits used
808
in the last byte when flushing to a byte boundary. The result is in 1..8, or
809
0 if there has not yet been a flush. This helps determine the location of
810
the last bit of a deflate stream.
811
812
deflateUsed returns Z_OK if success, or Z_STREAM_ERROR if the source
813
stream state was inconsistent.
814
*/
815
816
ZEXTERN int ZEXPORT deflatePrime(z_streamp strm,
817
int bits,
818
int value);
819
/*
820
deflatePrime() inserts bits in the deflate output stream. The intent
821
is that this function is used to start off the deflate output with the bits
822
leftover from a previous deflate stream when appending to it. As such, this
823
function can only be used for raw deflate, and must be used before the first
824
deflate() call after a deflateInit2() or deflateReset(). bits must be less
825
than or equal to 16, and that many of the least significant bits of value
826
will be inserted in the output.
827
828
deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
829
room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
830
source stream state was inconsistent.
831
*/
832
833
ZEXTERN int ZEXPORT deflateSetHeader(z_streamp strm,
834
gz_headerp head);
835
/*
836
deflateSetHeader() provides gzip header information for when a gzip
837
stream is requested by deflateInit2(). deflateSetHeader() may be called
838
after deflateInit2() or deflateReset() and before the first call of
839
deflate(). The text, time, os, extra field, name, and comment information
840
in the provided gz_header structure are written to the gzip header (xflag is
841
ignored -- the extra flags are set according to the compression level). The
842
caller must assure that, if not Z_NULL, name and comment are terminated with
843
a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
844
available there. If hcrc is true, a gzip header crc is included. Note that
845
the current versions of the command-line version of gzip (up through version
846
1.3.x) do not support header crc's, and will report that it is a "multi-part
847
gzip file" and give up.
848
849
If deflateSetHeader is not used, the default gzip header has text false,
850
the time set to zero, and os set to the current operating system, with no
851
extra, name, or comment fields. The gzip header is returned to the default
852
state by deflateReset().
853
854
deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
855
stream state was inconsistent.
856
*/
857
858
/*
859
ZEXTERN int ZEXPORT inflateInit2(z_streamp strm,
860
int windowBits);
861
862
This is another version of inflateInit with an extra parameter. The
863
fields next_in, avail_in, zalloc, zfree and opaque must be initialized
864
before by the caller.
865
866
The windowBits parameter is the base two logarithm of the maximum window
867
size (the size of the history buffer). It should be in the range 8..15 for
868
this version of the library. The default value is 15 if inflateInit is used
869
instead. windowBits must be greater than or equal to the windowBits value
870
provided to deflateInit2() while compressing, or it must be equal to 15 if
871
deflateInit2() was not used. If a compressed stream with a larger window
872
size is given as input, inflate() will return with the error code
873
Z_DATA_ERROR instead of trying to allocate a larger window.
874
875
windowBits can also be zero to request that inflate use the window size in
876
the zlib header of the compressed stream.
877
878
windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
879
determines the window size. inflate() will then process raw deflate data,
880
not looking for a zlib or gzip header, not generating a check value, and not
881
looking for any check values for comparison at the end of the stream. This
882
is for use with other formats that use the deflate compressed data format
883
such as zip. Those formats provide their own check values. If a custom
884
format is developed using the raw deflate format for compressed data, it is
885
recommended that a check value such as an Adler-32 or a CRC-32 be applied to
886
the uncompressed data as is done in the zlib, gzip, and zip formats. For
887
most applications, the zlib format should be used as is. Note that comments
888
above on the use in deflateInit2() applies to the magnitude of windowBits.
889
890
windowBits can also be greater than 15 for optional gzip decoding. Add
891
32 to windowBits to enable zlib and gzip decoding with automatic header
892
detection, or add 16 to decode only the gzip format (the zlib format will
893
return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
894
CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see
895
below), inflate() will *not* automatically decode concatenated gzip members.
896
inflate() will return Z_STREAM_END at the end of the gzip member. The state
897
would need to be reset to continue decoding a subsequent gzip member. This
898
*must* be done if there is more data after a gzip member, in order for the
899
decompression to be compliant with the gzip standard (RFC 1952).
900
901
inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
902
memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
903
version assumed by the caller, or Z_STREAM_ERROR if the parameters are
904
invalid, such as a null pointer to the structure. msg is set to null if
905
there is no error message. inflateInit2 does not perform any decompression
906
apart from possibly reading the zlib header if present: actual decompression
907
will be done by inflate(). (So next_in and avail_in may be modified, but
908
next_out and avail_out are unused and unchanged.) The current implementation
909
of inflateInit2() does not process any header information -- that is
910
deferred until inflate() is called.
911
*/
912
913
ZEXTERN int ZEXPORT inflateSetDictionary(z_streamp strm,
914
const Bytef *dictionary,
915
uInt dictLength);
916
/*
917
Initializes the decompression dictionary from the given uncompressed byte
918
sequence. This function must be called immediately after a call of inflate,
919
if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
920
can be determined from the Adler-32 value returned by that call of inflate.
921
The compressor and decompressor must use exactly the same dictionary (see
922
deflateSetDictionary). For raw inflate, this function can be called at any
923
time to set the dictionary. If the provided dictionary is smaller than the
924
window and there is already data in the window, then the provided dictionary
925
will amend what's there. The application must insure that the dictionary
926
that was used for compression is provided.
927
928
inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
929
parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
930
inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
931
expected one (incorrect Adler-32 value). inflateSetDictionary does not
932
perform any decompression: this will be done by subsequent calls of
933
inflate().
934
*/
935
936
ZEXTERN int ZEXPORT inflateGetDictionary(z_streamp strm,
937
Bytef *dictionary,
938
uInt *dictLength);
939
/*
940
Returns the sliding dictionary being maintained by inflate. dictLength is
941
set to the number of bytes in the dictionary, and that many bytes are copied
942
to dictionary. dictionary must have enough space, where 32768 bytes is
943
always enough. If inflateGetDictionary() is called with dictionary equal to
944
Z_NULL, then only the dictionary length is returned, and nothing is copied.
945
Similarly, if dictLength is Z_NULL, then it is not set.
946
947
inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
948
stream state is inconsistent.
949
*/
950
951
ZEXTERN int ZEXPORT inflateSync(z_streamp strm);
952
/*
953
Skips invalid compressed data until a possible full flush point (see above
954
for the description of deflate with Z_FULL_FLUSH) can be found, or until all
955
available input is skipped. No output is provided.
956
957
inflateSync searches for a 00 00 FF FF pattern in the compressed data.
958
All full flush points have this pattern, but not all occurrences of this
959
pattern are full flush points.
960
961
inflateSync returns Z_OK if a possible full flush point has been found,
962
Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
963
has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
964
In the success case, the application may save the current value of total_in
965
which indicates where valid compressed data was found. In the error case,
966
the application may repeatedly call inflateSync, providing more input each
967
time, until success or end of the input data.
968
*/
969
970
ZEXTERN int ZEXPORT inflateCopy(z_streamp dest,
971
z_streamp source);
972
/*
973
Sets the destination stream as a complete copy of the source stream.
974
975
This function can be useful when randomly accessing a large stream. The
976
first pass through the stream can periodically record the inflate state,
977
allowing restarting inflate at those points when randomly accessing the
978
stream.
979
980
inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
981
enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
982
(such as zalloc being Z_NULL). msg is left unchanged in both source and
983
destination.
984
*/
985
986
ZEXTERN int ZEXPORT inflateReset(z_streamp strm);
987
/*
988
This function is equivalent to inflateEnd followed by inflateInit,
989
but does not free and reallocate the internal decompression state. The
990
stream will keep attributes that may have been set by inflateInit2.
991
total_in, total_out, adler, and msg are initialized.
992
993
inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
994
stream state was inconsistent (such as zalloc or state being Z_NULL).
995
*/
996
997
ZEXTERN int ZEXPORT inflateReset2(z_streamp strm,
998
int windowBits);
999
/*
1000
This function is the same as inflateReset, but it also permits changing
1001
the wrap and window size requests. The windowBits parameter is interpreted
1002
the same as it is for inflateInit2. If the window size is changed, then the
1003
memory allocated for the window is freed, and the window will be reallocated
1004
by inflate() if needed.
1005
1006
inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
1007
stream state was inconsistent (such as zalloc or state being Z_NULL), or if
1008
the windowBits parameter is invalid.
1009
*/
1010
1011
ZEXTERN int ZEXPORT inflatePrime(z_streamp strm,
1012
int bits,
1013
int value);
1014
/*
1015
This function inserts bits in the inflate input stream. The intent is to
1016
use inflatePrime() to start inflating at a bit position in the middle of a
1017
byte. The provided bits will be used before any bytes are used from
1018
next_in. This function should be used with raw inflate, before the first
1019
inflate() call, after inflateInit2() or inflateReset(). It can also be used
1020
after an inflate() return indicates the end of a deflate block or header
1021
when using Z_BLOCK. bits must be less than or equal to 16, and that many of
1022
the least significant bits of value will be inserted in the input. The
1023
other bits in value can be non-zero, and will be ignored.
1024
1025
If bits is negative, then the input stream bit buffer is emptied. Then
1026
inflatePrime() can be called again to put bits in the buffer. This is used
1027
to clear out bits leftover after feeding inflate a block description prior
1028
to feeding inflate codes.
1029
1030
inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
1031
stream state was inconsistent, or if bits is out of range. If inflate was
1032
in the middle of processing a header, trailer, or stored block lengths, then
1033
it is possible for there to be only eight bits available in the bit buffer.
1034
In that case, bits > 8 is considered out of range. However, when used as
1035
outlined above, there will always be 16 bits available in the buffer for
1036
insertion. As noted in its documentation above, inflate records the number
1037
of bits in the bit buffer on return in data_type. 32 minus that is the
1038
number of bits available for insertion. inflatePrime does not update
1039
data_type with the new number of bits in buffer.
1040
*/
1041
1042
ZEXTERN long ZEXPORT inflateMark(z_streamp strm);
1043
/*
1044
This function returns two values, one in the lower 16 bits of the return
1045
value, and the other in the remaining upper bits, obtained by shifting the
1046
return value down 16 bits. If the upper value is -1 and the lower value is
1047
zero, then inflate() is currently decoding information outside of a block.
1048
If the upper value is -1 and the lower value is non-zero, then inflate is in
1049
the middle of a stored block, with the lower value equaling the number of
1050
bytes from the input remaining to copy. If the upper value is not -1, then
1051
it is the number of bits back from the current bit position in the input of
1052
the code (literal or length/distance pair) currently being processed. In
1053
that case the lower value is the number of bytes already emitted for that
1054
code.
1055
1056
A code is being processed if inflate is waiting for more input to complete
1057
decoding of the code, or if it has completed decoding but is waiting for
1058
more output space to write the literal or match data.
1059
1060
inflateMark() is used to mark locations in the input data for random
1061
access, which may be at bit positions, and to note those cases where the
1062
output of a code may span boundaries of random access blocks. The current
1063
location in the input stream can be determined from avail_in and data_type
1064
as noted in the description for the Z_BLOCK flush parameter for inflate.
1065
1066
inflateMark returns the value noted above, or -65536 if the provided
1067
source stream state was inconsistent.
1068
*/
1069
1070
ZEXTERN int ZEXPORT inflateGetHeader(z_streamp strm,
1071
gz_headerp head);
1072
/*
1073
inflateGetHeader() requests that gzip header information be stored in the
1074
provided gz_header structure. inflateGetHeader() may be called after
1075
inflateInit2() or inflateReset(), and before the first call of inflate().
1076
As inflate() processes the gzip stream, head->done is zero until the header
1077
is completed, at which time head->done is set to one. If a zlib stream is
1078
being decoded, then head->done is set to -1 to indicate that there will be
1079
no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
1080
used to force inflate() to return immediately after header processing is
1081
complete and before any actual data is decompressed.
1082
1083
The text, time, xflags, and os fields are filled in with the gzip header
1084
contents. hcrc is set to true if there is a header CRC. (The header CRC
1085
was valid if done is set to one.) The extra, name, and comment pointers
1086
much each be either Z_NULL or point to space to store that information from
1087
the header. If extra is not Z_NULL, then extra_max contains the maximum
1088
number of bytes that can be written to extra. Once done is true, extra_len
1089
contains the actual extra field length, and extra contains the extra field,
1090
or that field truncated if extra_max is less than extra_len. If name is not
1091
Z_NULL, then up to name_max characters, including the terminating zero, are
1092
written there. If comment is not Z_NULL, then up to comm_max characters,
1093
including the terminating zero, are written there. The application can tell
1094
that the name or comment did not fit in the provided space by the absence of
1095
a terminating zero. If any of extra, name, or comment are not present in
1096
the header, then that field's pointer is set to Z_NULL. This allows the use
1097
of deflateSetHeader() with the returned structure to duplicate the header.
1098
Note that if those fields initially pointed to allocated memory, then the
1099
application will need to save them elsewhere so that they can be eventually
1100
freed.
1101
1102
If inflateGetHeader is not used, then the header information is simply
1103
discarded. The header is always checked for validity, including the header
1104
CRC if present. inflateReset() will reset the process to discard the header
1105
information. The application would need to call inflateGetHeader() again to
1106
retrieve the header from the next gzip stream.
1107
1108
inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
1109
stream state was inconsistent.
1110
*/
1111
1112
/*
1113
ZEXTERN int ZEXPORT inflateBackInit(z_streamp strm, int windowBits,
1114
unsigned char FAR *window);
1115
1116
Initialize the internal stream state for decompression using inflateBack()
1117
calls. The fields zalloc, zfree and opaque in strm must be initialized
1118
before the call. If zalloc and zfree are Z_NULL, then the default library-
1119
derived memory allocation routines are used. windowBits is the base two
1120
logarithm of the window size, in the range 8..15. window is a caller
1121
supplied buffer of that size. Except for special applications where it is
1122
assured that deflate was used with small window sizes, windowBits must be 15
1123
and a 32K byte window must be supplied to be able to decompress general
1124
deflate streams.
1125
1126
See inflateBack() for the usage of these routines.
1127
1128
inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
1129
the parameters are invalid, Z_MEM_ERROR if the internal state could not be
1130
allocated, or Z_VERSION_ERROR if the version of the library does not match
1131
the version of the header file.
1132
*/
1133
1134
typedef unsigned (*in_func)(void FAR *,
1135
z_const unsigned char FAR * FAR *);
1136
typedef int (*out_func)(void FAR *, unsigned char FAR *, unsigned);
1137
1138
ZEXTERN int ZEXPORT inflateBack(z_streamp strm,
1139
in_func in, void FAR *in_desc,
1140
out_func out, void FAR *out_desc);
1141
/*
1142
inflateBack() does a raw inflate with a single call using a call-back
1143
interface for input and output. This is potentially more efficient than
1144
inflate() for file i/o applications, in that it avoids copying between the
1145
output and the sliding window by simply making the window itself the output
1146
buffer. inflate() can be faster on modern CPUs when used with large
1147
buffers. inflateBack() trusts the application to not change the output
1148
buffer passed by the output function, at least until inflateBack() returns.
1149
1150
inflateBackInit() must be called first to allocate the internal state
1151
and to initialize the state with the user-provided window buffer.
1152
inflateBack() may then be used multiple times to inflate a complete, raw
1153
deflate stream with each call. inflateBackEnd() is then called to free the
1154
allocated state.
1155
1156
A raw deflate stream is one with no zlib or gzip header or trailer.
1157
This routine would normally be used in a utility that reads zip or gzip
1158
files and writes out uncompressed files. The utility would decode the
1159
header and process the trailer on its own, hence this routine expects only
1160
the raw deflate stream to decompress. This is different from the default
1161
behavior of inflate(), which expects a zlib header and trailer around the
1162
deflate stream.
1163
1164
inflateBack() uses two subroutines supplied by the caller that are then
1165
called by inflateBack() for input and output. inflateBack() calls those
1166
routines until it reads a complete deflate stream and writes out all of the
1167
uncompressed data, or until it encounters an error. The function's
1168
parameters and return types are defined above in the in_func and out_func
1169
typedefs. inflateBack() will call in(in_desc, &buf) which should return the
1170
number of bytes of provided input, and a pointer to that input in buf. If
1171
there is no input available, in() must return zero -- buf is ignored in that
1172
case -- and inflateBack() will return a buffer error. inflateBack() will
1173
call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].
1174
out() should return zero on success, or non-zero on failure. If out()
1175
returns non-zero, inflateBack() will return with an error. Neither in() nor
1176
out() are permitted to change the contents of the window provided to
1177
inflateBackInit(), which is also the buffer that out() uses to write from.
1178
The length written by out() will be at most the window size. Any non-zero
1179
amount of input may be provided by in().
1180
1181
For convenience, inflateBack() can be provided input on the first call by
1182
setting strm->next_in and strm->avail_in. If that input is exhausted, then
1183
in() will be called. Therefore strm->next_in must be initialized before
1184
calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
1185
immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
1186
must also be initialized, and then if strm->avail_in is not zero, input will
1187
initially be taken from strm->next_in[0 .. strm->avail_in - 1].
1188
1189
The in_desc and out_desc parameters of inflateBack() is passed as the
1190
first parameter of in() and out() respectively when they are called. These
1191
descriptors can be optionally used to pass any information that the caller-
1192
supplied in() and out() functions need to do their job.
1193
1194
On return, inflateBack() will set strm->next_in and strm->avail_in to
1195
pass back any unused input that was provided by the last in() call. The
1196
return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1197
if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1198
in the deflate stream (in which case strm->msg is set to indicate the nature
1199
of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1200
In the case of Z_BUF_ERROR, an input or output error can be distinguished
1201
using strm->next_in which will be Z_NULL only if in() returned an error. If
1202
strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1203
non-zero. (in() will always be called before out(), so strm->next_in is
1204
assured to be defined if out() returns non-zero.) Note that inflateBack()
1205
cannot return Z_OK.
1206
*/
1207
1208
ZEXTERN int ZEXPORT inflateBackEnd(z_streamp strm);
1209
/*
1210
All memory allocated by inflateBackInit() is freed.
1211
1212
inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1213
state was inconsistent.
1214
*/
1215
1216
ZEXTERN uLong ZEXPORT zlibCompileFlags(void);
1217
/* Return flags indicating compile-time options.
1218
1219
Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1220
1.0: size of uInt
1221
3.2: size of uLong
1222
5.4: size of voidpf (pointer)
1223
7.6: size of z_off_t
1224
1225
Compiler, assembler, and debug options:
1226
8: ZLIB_DEBUG
1227
9: ASMV or ASMINF -- use ASM code
1228
10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1229
11: 0 (reserved)
1230
1231
One-time table building (smaller code, but not thread-safe if true):
1232
12: BUILDFIXED -- build static block decoding tables when needed
1233
13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1234
14,15: 0 (reserved)
1235
1236
Library content (indicates missing functionality):
1237
16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1238
deflate code when not needed)
1239
17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1240
and decode gzip streams (to avoid linking crc code)
1241
18-19: 0 (reserved)
1242
1243
Operation variations (changes in library functionality):
1244
20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1245
21: FASTEST -- deflate algorithm with only one, lowest compression level
1246
22,23: 0 (reserved)
1247
1248
The sprintf variant used by gzprintf (all zeros is best):
1249
24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1250
25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() is not secure!
1251
26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1252
27: 0 = gzprintf() present, 1 = not -- 1 means gzprintf() returns an error
1253
1254
Remainder:
1255
28-31: 0 (reserved)
1256
*/
1257
1258
#ifndef Z_SOLO
1259
1260
/* utility functions */
1261
1262
/*
1263
The following utility functions are implemented on top of the basic
1264
stream-oriented functions. To simplify the interface, some default options
1265
are assumed (compression level and memory usage, standard memory allocation
1266
functions). The source code of these utility functions can be modified if
1267
you need special options. The _z versions of the functions use the size_t
1268
type for lengths. Note that a long is 32 bits on Windows.
1269
*/
1270
1271
ZEXTERN int ZEXPORT compress(Bytef *dest, uLongf *destLen,
1272
const Bytef *source, uLong sourceLen);
1273
ZEXTERN int ZEXPORT compress_z(Bytef *dest, z_size_t *destLen,
1274
const Bytef *source, z_size_t sourceLen);
1275
/*
1276
Compresses the source buffer into the destination buffer. sourceLen is
1277
the byte length of the source buffer. Upon entry, destLen is the total size
1278
of the destination buffer, which must be at least the value returned by
1279
compressBound(sourceLen). Upon exit, destLen is the actual size of the
1280
compressed data. compress() is equivalent to compress2() with a level
1281
parameter of Z_DEFAULT_COMPRESSION.
1282
1283
compress returns Z_OK if success, Z_MEM_ERROR if there was not
1284
enough memory, Z_BUF_ERROR if there was not enough room in the output
1285
buffer.
1286
*/
1287
1288
ZEXTERN int ZEXPORT compress2(Bytef *dest, uLongf *destLen,
1289
const Bytef *source, uLong sourceLen,
1290
int level);
1291
ZEXTERN int ZEXPORT compress2_z(Bytef *dest, z_size_t *destLen,
1292
const Bytef *source, z_size_t sourceLen,
1293
int level);
1294
/*
1295
Compresses the source buffer into the destination buffer. The level
1296
parameter has the same meaning as in deflateInit. sourceLen is the byte
1297
length of the source buffer. Upon entry, destLen is the total size of the
1298
destination buffer, which must be at least the value returned by
1299
compressBound(sourceLen). Upon exit, destLen is the actual size of the
1300
compressed data.
1301
1302
compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1303
memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1304
Z_STREAM_ERROR if the level parameter is invalid.
1305
*/
1306
1307
ZEXTERN uLong ZEXPORT compressBound(uLong sourceLen);
1308
ZEXTERN z_size_t ZEXPORT compressBound_z(z_size_t sourceLen);
1309
/*
1310
compressBound() returns an upper bound on the compressed size after
1311
compress() or compress2() on sourceLen bytes. It would be used before a
1312
compress() or compress2() call to allocate the destination buffer.
1313
*/
1314
1315
ZEXTERN int ZEXPORT uncompress(Bytef *dest, uLongf *destLen,
1316
const Bytef *source, uLong sourceLen);
1317
ZEXTERN int ZEXPORT uncompress_z(Bytef *dest, z_size_t *destLen,
1318
const Bytef *source, z_size_t sourceLen);
1319
/*
1320
Decompresses the source buffer into the destination buffer. sourceLen is
1321
the byte length of the source buffer. On entry, *destLen is the total size
1322
of the destination buffer, which must be large enough to hold the entire
1323
uncompressed data. (The size of the uncompressed data must have been saved
1324
previously by the compressor and transmitted to the decompressor by some
1325
mechanism outside the scope of this compression library.) On exit, *destLen
1326
is the actual size of the uncompressed data.
1327
1328
uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1329
enough memory, Z_BUF_ERROR if there was not enough room in the output
1330
buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In
1331
the case where there is not enough room, uncompress() will fill the output
1332
buffer with the uncompressed data up to that point.
1333
*/
1334
1335
ZEXTERN int ZEXPORT uncompress2(Bytef *dest, uLongf *destLen,
1336
const Bytef *source, uLong *sourceLen);
1337
ZEXTERN int ZEXPORT uncompress2_z(Bytef *dest, z_size_t *destLen,
1338
const Bytef *source, z_size_t *sourceLen);
1339
/*
1340
Same as uncompress, except that sourceLen is a pointer, where the
1341
length of the source is *sourceLen. On return, *sourceLen is the number of
1342
source bytes consumed.
1343
*/
1344
1345
/* gzip file access functions */
1346
1347
/*
1348
This library supports reading and writing files in gzip (.gz) format with
1349
an interface similar to that of stdio, using the functions that start with
1350
"gz". The gzip format is different from the zlib format. gzip is a gzip
1351
wrapper, documented in RFC 1952, wrapped around a deflate stream.
1352
*/
1353
1354
typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */
1355
1356
/*
1357
ZEXTERN gzFile ZEXPORT gzopen(const char *path, const char *mode);
1358
1359
Open the gzip (.gz) file at path for reading and decompressing, or
1360
compressing and writing. The mode parameter is as in fopen ("rb" or "wb")
1361
but can also include a compression level ("wb9") or a strategy: 'f' for
1362
filtered data as in "wb6f", 'h' for Huffman-only compression as in "wb1h",
1363
'R' for run-length encoding as in "wb1R", or 'F' for fixed code compression
1364
as in "wb9F". (See the description of deflateInit2 for more information
1365
about the strategy parameter.) 'T' will request transparent writing or
1366
appending with no compression and not using the gzip format. 'T' cannot be
1367
used to force transparent reading. Transparent reading is automatically
1368
performed if there is no gzip header at the start. Transparent reading can
1369
be disabled with the 'G' option, which will instead return an error if there
1370
is no gzip header. 'N' will open the file in non-blocking mode.
1371
1372
'a' can be used instead of 'w' to request that the gzip stream that will
1373
be written be appended to the file. '+' will result in an error, since
1374
reading and writing to the same gzip file is not supported. The addition of
1375
'x' when writing will create the file exclusively, which fails if the file
1376
already exists. On systems that support it, the addition of 'e' when
1377
reading or writing will set the flag to close the file on an execve() call.
1378
1379
These functions, as well as gzip, will read and decode a sequence of gzip
1380
streams in a file. The append function of gzopen() can be used to create
1381
such a file. (Also see gzflush() for another way to do this.) When
1382
appending, gzopen does not test whether the file begins with a gzip stream,
1383
nor does it look for the end of the gzip streams to begin appending. gzopen
1384
will simply append a gzip stream to the existing file.
1385
1386
gzopen can be used to read a file which is not in gzip format; in this
1387
case gzread will directly read from the file without decompression. When
1388
reading, this will be detected automatically by looking for the magic two-
1389
byte gzip header.
1390
1391
gzopen returns NULL if the file could not be opened, if there was
1392
insufficient memory to allocate the gzFile state, or if an invalid mode was
1393
specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1394
errno can be checked to determine if the reason gzopen failed was that the
1395
file could not be opened. Note that if 'N' is in mode for non-blocking, the
1396
open() itself can fail in order to not block. In that case gzopen() will
1397
return NULL and errno will be EAGAIN or ENONBLOCK. The call to gzopen() can
1398
then be re-tried. If the application would like to block on opening the
1399
file, then it can use open() without O_NONBLOCK, and then gzdopen() with the
1400
resulting file descriptor and 'N' in the mode, which will set it to non-
1401
blocking.
1402
*/
1403
1404
ZEXTERN gzFile ZEXPORT gzdopen(int fd, const char *mode);
1405
/*
1406
Associate a gzFile with the file descriptor fd. File descriptors are
1407
obtained from calls like open, dup, creat, pipe or fileno (if the file has
1408
been previously opened with fopen). The mode parameter is as in gzopen. An
1409
'e' in mode will set fd's flag to close the file on an execve() call. An 'N'
1410
in mode will set fd's non-blocking flag.
1411
1412
The next call of gzclose on the returned gzFile will also close the file
1413
descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1414
fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1415
mode);. The duplicated descriptor should be saved to avoid a leak, since
1416
gzdopen does not close fd if it fails. If you are using fileno() to get the
1417
file descriptor from a FILE *, then you will have to use dup() to avoid
1418
double-close()ing the file descriptor. Both gzclose() and fclose() will
1419
close the associated file descriptor, so they need to have different file
1420
descriptors.
1421
1422
gzdopen returns NULL if there was insufficient memory to allocate the
1423
gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1424
provided, or '+' was provided), or if fd is -1. The file descriptor is not
1425
used until the next gz* read, write, seek, or close operation, so gzdopen
1426
will not detect if fd is invalid (unless fd is -1).
1427
*/
1428
1429
ZEXTERN int ZEXPORT gzbuffer(gzFile file, unsigned size);
1430
/*
1431
Set the internal buffer size used by this library's functions for file to
1432
size. The default buffer size is 8192 bytes. This function must be called
1433
after gzopen() or gzdopen(), and before any other calls that read or write
1434
the file. The buffer memory allocation is always deferred to the first read
1435
or write. Three times that size in buffer space is allocated. A larger
1436
buffer size of, for example, 64K or 128K bytes will noticeably increase the
1437
speed of decompression (reading).
1438
1439
The new buffer size also affects the maximum length for gzprintf().
1440
1441
gzbuffer() returns 0 on success, or -1 on failure, such as being called
1442
too late.
1443
*/
1444
1445
ZEXTERN int ZEXPORT gzsetparams(gzFile file, int level, int strategy);
1446
/*
1447
Dynamically update the compression level and strategy for file. See the
1448
description of deflateInit2 for the meaning of these parameters. Previously
1449
provided data is flushed before applying the parameter changes.
1450
1451
gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not
1452
opened for writing, Z_ERRNO if there is an error writing the flushed data,
1453
or Z_MEM_ERROR if there is a memory allocation error.
1454
*/
1455
1456
ZEXTERN int ZEXPORT gzread(gzFile file, voidp buf, unsigned len);
1457
/*
1458
Read and decompress up to len uncompressed bytes from file into buf. If
1459
the input file is not in gzip format, gzread copies the given number of
1460
bytes into the buffer directly from the file.
1461
1462
After reaching the end of a gzip stream in the input, gzread will continue
1463
to read, looking for another gzip stream. Any number of gzip streams may be
1464
concatenated in the input file, and will all be decompressed by gzread().
1465
If something other than a gzip stream is encountered after a gzip stream,
1466
that remaining trailing garbage is ignored (and no error is returned).
1467
1468
gzread can be used to read a gzip file that is being concurrently written.
1469
Upon reaching the end of the input, gzread will return with the available
1470
data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
1471
gzclearerr can be used to clear the end of file indicator in order to permit
1472
gzread to be tried again. Z_OK indicates that a gzip stream was completed
1473
on the last gzread. Z_BUF_ERROR indicates that the input file ended in the
1474
middle of a gzip stream. Note that gzread does not return -1 in the event
1475
of an incomplete gzip stream. This error is deferred until gzclose(), which
1476
will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
1477
stream. Alternatively, gzerror can be used before gzclose to detect this
1478
case.
1479
1480
gzread can be used to read a gzip file on a non-blocking device. If the
1481
input stalls and there is no uncompressed data to return, then gzread() will
1482
return -1, and errno will be EAGAIN or EWOULDBLOCK. gzread() can then be
1483
called again.
1484
1485
gzread returns the number of uncompressed bytes actually read, less than
1486
len for end of file, or -1 for error. If len is too large to fit in an int,
1487
then nothing is read, -1 is returned, and the error state is set to
1488
Z_STREAM_ERROR. If some data was read before an error, then that data is
1489
returned until exhausted, after which the next call will signal the error.
1490
*/
1491
1492
ZEXTERN z_size_t ZEXPORT gzfread(voidp buf, z_size_t size, z_size_t nitems,
1493
gzFile file);
1494
/*
1495
Read and decompress up to nitems items of size size from file into buf,
1496
otherwise operating as gzread() does. This duplicates the interface of
1497
stdio's fread(), with size_t request and return types. If the library
1498
defines size_t, then z_size_t is identical to size_t. If not, then z_size_t
1499
is an unsigned integer type that can contain a pointer.
1500
1501
gzfread() returns the number of full items read of size size, or zero if
1502
the end of the file was reached and a full item could not be read, or if
1503
there was an error. gzerror() must be consulted if zero is returned in
1504
order to determine if there was an error. If the multiplication of size and
1505
nitems overflows, i.e. the product does not fit in a z_size_t, then nothing
1506
is read, zero is returned, and the error state is set to Z_STREAM_ERROR.
1507
1508
In the event that the end of file is reached and only a partial item is
1509
available at the end, i.e. the remaining uncompressed data length is not a
1510
multiple of size, then the final partial item is nevertheless read into buf
1511
and the end-of-file flag is set. The length of the partial item read is not
1512
provided, but could be inferred from the result of gztell(). This behavior
1513
is the same as that of fread() implementations in common libraries. This
1514
could result in data loss if used with size != 1 when reading a concurrently
1515
written file or a non-blocking file. In that case, use size == 1 or gzread()
1516
instead.
1517
*/
1518
1519
ZEXTERN int ZEXPORT gzwrite(gzFile file, voidpc buf, unsigned len);
1520
/*
1521
Compress and write the len uncompressed bytes at buf to file. gzwrite
1522
returns the number of uncompressed bytes written, or 0 in case of error or
1523
if len is 0. If the write destination is non-blocking, then gzwrite() may
1524
return a number of bytes written that is not 0 and less than len.
1525
1526
If len does not fit in an int, then 0 is returned and nothing is written.
1527
*/
1528
1529
ZEXTERN z_size_t ZEXPORT gzfwrite(voidpc buf, z_size_t size,
1530
z_size_t nitems, gzFile file);
1531
/*
1532
Compress and write nitems items of size size from buf to file, duplicating
1533
the interface of stdio's fwrite(), with size_t request and return types. If
1534
the library defines size_t, then z_size_t is identical to size_t. If not,
1535
then z_size_t is an unsigned integer type that can contain a pointer.
1536
1537
gzfwrite() returns the number of full items written of size size, or zero
1538
if there was an error. If the multiplication of size and nitems overflows,
1539
i.e. the product does not fit in a z_size_t, then nothing is written, zero
1540
is returned, and the error state is set to Z_STREAM_ERROR.
1541
1542
If writing a concurrently read file or a non-blocking file with size != 1,
1543
a partial item could be written, with no way of knowing how much of it was
1544
not written, resulting in data loss. In that case, use size == 1 or
1545
gzwrite() instead.
1546
*/
1547
1548
#if defined(STDC) || defined(Z_HAVE_STDARG_H)
1549
ZEXTERN int ZEXPORTVA gzprintf(gzFile file, const char *format, ...);
1550
#else
1551
ZEXTERN int ZEXPORTVA gzprintf();
1552
#endif
1553
/*
1554
Convert, format, compress, and write the arguments (...) to file under
1555
control of the string format, as in fprintf. gzprintf returns the number of
1556
uncompressed bytes actually written, or a negative zlib error code in case
1557
of error. The number of uncompressed bytes written is limited to 8191, or
1558
one less than the buffer size given to gzbuffer(). The caller should assure
1559
that this limit is not exceeded. If it is exceeded, then gzprintf() will
1560
return an error (0) with nothing written.
1561
1562
In that last case, there may also be a buffer overflow with unpredictable
1563
consequences, which is possible only if zlib was compiled with the insecure
1564
functions sprintf() or vsprintf(), because the secure snprintf() and
1565
vsnprintf() functions were not available. That would only be the case for
1566
a non-ANSI C compiler. zlib may have been built without gzprintf() because
1567
secure functions were not available and having gzprintf() be insecure was
1568
not an option, in which case, gzprintf() returns Z_STREAM_ERROR. All of
1569
these possibilities can be determined using zlibCompileFlags().
1570
1571
If a Z_BUF_ERROR is returned, then nothing was written due to a stall on
1572
the non-blocking write destination.
1573
*/
1574
1575
ZEXTERN int ZEXPORT gzputs(gzFile file, const char *s);
1576
/*
1577
Compress and write the given null-terminated string s to file, excluding
1578
the terminating null character.
1579
1580
gzputs returns the number of characters written, or -1 in case of error.
1581
The number of characters written may be less than the length of the string
1582
if the write destination is non-blocking.
1583
1584
If the length of the string does not fit in an int, then -1 is returned
1585
and nothing is written.
1586
*/
1587
1588
ZEXTERN char * ZEXPORT gzgets(gzFile file, char *buf, int len);
1589
/*
1590
Read and decompress bytes from file into buf, until len-1 characters are
1591
read, or until a newline character is read and transferred to buf, or an
1592
end-of-file condition is encountered. If any characters are read or if len
1593
is one, the string is terminated with a null character. If no characters
1594
are read due to an end-of-file or len is less than one, then the buffer is
1595
left untouched.
1596
1597
gzgets returns buf which is a null-terminated string, or it returns NULL
1598
for end-of-file or in case of error. If some data was read before an error,
1599
then that data is returned until exhausted, after which the next call will
1600
return NULL to signal the error.
1601
1602
gzgets can be used on a file being concurrently written, and on a non-
1603
blocking device, both as for gzread(). However lines may be broken in the
1604
middle, leaving it up to the application to reassemble them as needed.
1605
*/
1606
1607
ZEXTERN int ZEXPORT gzputc(gzFile file, int c);
1608
/*
1609
Compress and write c, converted to an unsigned char, into file. gzputc
1610
returns the value that was written, or -1 in case of error.
1611
*/
1612
1613
ZEXTERN int ZEXPORT gzgetc(gzFile file);
1614
/*
1615
Read and decompress one byte from file. gzgetc returns this byte or -1 in
1616
case of end of file or error. If some data was read before an error, then
1617
that data is returned until exhausted, after which the next call will return
1618
-1 to signal the error.
1619
1620
This is implemented as a macro for speed. As such, it does not do all of
1621
the checking the other functions do. I.e. it does not check to see if file
1622
is NULL, nor whether the structure file points to has been clobbered or not.
1623
1624
gzgetc can be used to read a gzip file on a non-blocking device. If the
1625
input stalls and there is no uncompressed data to return, then gzgetc() will
1626
return -1, and errno will be EAGAIN or EWOULDBLOCK. gzread() can then be
1627
called again.
1628
*/
1629
1630
ZEXTERN int ZEXPORT gzungetc(int c, gzFile file);
1631
/*
1632
Push c back onto the stream for file to be read as the first character on
1633
the next read. At least one character of push-back is always allowed.
1634
gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1635
fail if c is -1, and may fail if a character has been pushed but not read
1636
yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
1637
output buffer size of pushed characters is allowed. (See gzbuffer above.)
1638
The pushed character will be discarded if the stream is repositioned with
1639
gzseek() or gzrewind().
1640
1641
gzungetc(-1, file) will force any pending seek to execute. Then gztell()
1642
will report the position, even if the requested seek reached end of file.
1643
This can be used to determine the number of uncompressed bytes in a gzip
1644
file without having to read it into a buffer.
1645
*/
1646
1647
ZEXTERN int ZEXPORT gzflush(gzFile file, int flush);
1648
/*
1649
Flush all pending output to file. The parameter flush is as in the
1650
deflate() function. The return value is the zlib error number (see function
1651
gzerror below). gzflush is only permitted when writing.
1652
1653
If the flush parameter is Z_FINISH, the remaining data is written and the
1654
gzip stream is completed in the output. If gzwrite() is called again, a new
1655
gzip stream will be started in the output. gzread() is able to read such
1656
concatenated gzip streams.
1657
1658
gzflush should be called only when strictly necessary because it will
1659
degrade compression if called too often.
1660
*/
1661
1662
/*
1663
ZEXTERN z_off_t ZEXPORT gzseek(gzFile file,
1664
z_off_t offset, int whence);
1665
1666
Set the starting position to offset relative to whence for the next gzread
1667
or gzwrite on file. The offset represents a number of bytes in the
1668
uncompressed data stream. The whence parameter is defined as in lseek(2);
1669
the value SEEK_END is not supported.
1670
1671
If the file is opened for reading, this function is emulated but can be
1672
extremely slow. If the file is opened for writing, only forward seeks are
1673
supported; gzseek then compresses a sequence of zeroes up to the new
1674
starting position. For reading or writing, any actual seeking is deferred
1675
until the next read or write operation, or close operation when writing.
1676
1677
gzseek returns the resulting offset location as measured in bytes from
1678
the beginning of the uncompressed stream, or -1 in case of error, in
1679
particular if the file is opened for writing and the new starting position
1680
would be before the current position.
1681
*/
1682
1683
ZEXTERN int ZEXPORT gzrewind(gzFile file);
1684
/*
1685
Rewind file. This function is supported only for reading.
1686
1687
gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET).
1688
*/
1689
1690
/*
1691
ZEXTERN z_off_t ZEXPORT gztell(gzFile file);
1692
1693
Return the starting position for the next gzread or gzwrite on file.
1694
This position represents a number of bytes in the uncompressed data stream,
1695
and is zero when starting, even if appending or reading a gzip stream from
1696
the middle of a file using gzdopen().
1697
1698
gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1699
*/
1700
1701
/*
1702
ZEXTERN z_off_t ZEXPORT gzoffset(gzFile file);
1703
1704
Return the current compressed (actual) read or write offset of file. This
1705
offset includes the count of bytes that precede the gzip stream, for example
1706
when appending or when using gzdopen() for reading. When reading, the
1707
offset does not include as yet unused buffered input. This information can
1708
be used for a progress indicator. On error, gzoffset() returns -1.
1709
*/
1710
1711
ZEXTERN int ZEXPORT gzeof(gzFile file);
1712
/*
1713
Return true (1) if the end-of-file indicator for file has been set while
1714
reading, false (0) otherwise. Note that the end-of-file indicator is set
1715
only if the read tried to go past the end of the input, but came up short.
1716
Therefore, just like feof(), gzeof() may return false even if there is no
1717
more data to read, in the event that the last read request was for the exact
1718
number of bytes remaining in the input file. This will happen if the input
1719
file size is an exact multiple of the buffer size.
1720
1721
If gzeof() returns true, then the read functions will return no more data,
1722
unless the end-of-file indicator is reset by gzclearerr() and the input file
1723
has grown since the previous end of file was detected.
1724
*/
1725
1726
ZEXTERN int ZEXPORT gzdirect(gzFile file);
1727
/*
1728
Return true (1) if file is being copied directly while reading, or false
1729
(0) if file is a gzip stream being decompressed.
1730
1731
If the input file is empty, gzdirect() will return true, since the input
1732
does not contain a gzip stream.
1733
1734
If gzdirect() is used immediately after gzopen() or gzdopen() it will
1735
cause buffers to be allocated to allow reading the file to determine if it
1736
is a gzip file. Therefore if gzbuffer() is used, it should be called before
1737
gzdirect(). If the input is being written concurrently or the device is non-
1738
blocking, then gzdirect() may give a different answer once four bytes of
1739
input have been accumulated, which is what is needed to confirm or deny a
1740
gzip header. Before this, gzdirect() will return true (1).
1741
1742
When writing, gzdirect() returns true (1) if transparent writing was
1743
requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note:
1744
gzdirect() is not needed when writing. Transparent writing must be
1745
explicitly requested, so the application already knows the answer. When
1746
linking statically, using gzdirect() will include all of the zlib code for
1747
gzip file reading and decompression, which may not be desired.)
1748
*/
1749
1750
ZEXTERN int ZEXPORT gzclose(gzFile file);
1751
/*
1752
Flush all pending output for file, if necessary, close file and
1753
deallocate the (de)compression state. Note that once file is closed, you
1754
cannot call gzerror with file, since its structures have been deallocated.
1755
gzclose must not be called more than once on the same file, just as free
1756
must not be called more than once on the same allocation.
1757
1758
gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1759
file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
1760
last read ended in the middle of a gzip stream, or Z_OK on success.
1761
*/
1762
1763
ZEXTERN int ZEXPORT gzclose_r(gzFile file);
1764
ZEXTERN int ZEXPORT gzclose_w(gzFile file);
1765
/*
1766
Same as gzclose(), but gzclose_r() is only for use when reading, and
1767
gzclose_w() is only for use when writing or appending. The advantage to
1768
using these instead of gzclose() is that they avoid linking in zlib
1769
compression or decompression code that is not used when only reading or only
1770
writing respectively. If gzclose() is used, then both compression and
1771
decompression code will be included the application when linking to a static
1772
zlib library.
1773
*/
1774
1775
ZEXTERN const char * ZEXPORT gzerror(gzFile file, int *errnum);
1776
/*
1777
Return the error message for the last error which occurred on file.
1778
If errnum is not NULL, *errnum is set to zlib error number. If an error
1779
occurred in the file system and not in the compression library, *errnum is
1780
set to Z_ERRNO and the application may consult errno to get the exact error
1781
code.
1782
1783
The application must not modify the returned string. Future calls to
1784
this function may invalidate the previously returned string. If file is
1785
closed, then the string previously returned by gzerror will no longer be
1786
available.
1787
1788
gzerror() should be used to distinguish errors from end-of-file for those
1789
functions above that do not distinguish those cases in their return values.
1790
*/
1791
1792
ZEXTERN void ZEXPORT gzclearerr(gzFile file);
1793
/*
1794
Clear the error and end-of-file flags for file. This is analogous to the
1795
clearerr() function in stdio. This is useful for continuing to read a gzip
1796
file that is being written concurrently.
1797
*/
1798
1799
#endif /* !Z_SOLO */
1800
1801
/* checksum functions */
1802
1803
/*
1804
These functions are not related to compression but are exported
1805
anyway because they might be useful in applications using the compression
1806
library.
1807
*/
1808
1809
ZEXTERN uLong ZEXPORT adler32(uLong adler, const Bytef *buf, uInt len);
1810
/*
1811
Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1812
return the updated checksum. An Adler-32 value is in the range of a 32-bit
1813
unsigned integer. If buf is Z_NULL, this function returns the required
1814
initial value for the checksum.
1815
1816
An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed
1817
much faster.
1818
1819
Usage example:
1820
1821
uLong adler = adler32(0L, Z_NULL, 0);
1822
1823
while (read_buffer(buffer, length) != EOF) {
1824
adler = adler32(adler, buffer, length);
1825
}
1826
if (adler != original_adler) error();
1827
*/
1828
1829
ZEXTERN uLong ZEXPORT adler32_z(uLong adler, const Bytef *buf,
1830
z_size_t len);
1831
/*
1832
Same as adler32(), but with a size_t length. Note that a long is 32 bits
1833
on Windows.
1834
*/
1835
1836
/*
1837
ZEXTERN uLong ZEXPORT adler32_combine(uLong adler1, uLong adler2,
1838
z_off_t len2);
1839
1840
Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1841
and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1842
each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1843
seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note
1844
that the z_off_t type (like off_t) is a signed integer. If len2 is
1845
negative, the result has no meaning or utility.
1846
*/
1847
1848
ZEXTERN uLong ZEXPORT crc32(uLong crc, const Bytef *buf, uInt len);
1849
/*
1850
Update a running CRC-32 with the bytes buf[0..len-1] and return the
1851
updated CRC-32. A CRC-32 value is in the range of a 32-bit unsigned integer.
1852
If buf is Z_NULL, this function returns the required initial value for the
1853
crc. Pre- and post-conditioning (one's complement) is performed within this
1854
function so it shouldn't be done by the application.
1855
1856
Usage example:
1857
1858
uLong crc = crc32(0L, Z_NULL, 0);
1859
1860
while (read_buffer(buffer, length) != EOF) {
1861
crc = crc32(crc, buffer, length);
1862
}
1863
if (crc != original_crc) error();
1864
*/
1865
1866
ZEXTERN uLong ZEXPORT crc32_z(uLong crc, const Bytef *buf,
1867
z_size_t len);
1868
/*
1869
Same as crc32(), but with a size_t length. Note that a long is 32 bits on
1870
Windows.
1871
*/
1872
1873
/*
1874
ZEXTERN uLong ZEXPORT crc32_combine(uLong crc1, uLong crc2, z_off_t len2);
1875
1876
Combine two CRC-32 check values into one. For two sequences of bytes,
1877
seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1878
calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1879
check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1880
len2. len2 must be non-negative, otherwise zero is returned.
1881
*/
1882
1883
/*
1884
ZEXTERN uLong ZEXPORT crc32_combine_gen(z_off_t len2);
1885
1886
Return the operator corresponding to length len2, to be used with
1887
crc32_combine_op(). len2 must be non-negative, otherwise zero is returned.
1888
*/
1889
1890
ZEXTERN uLong ZEXPORT crc32_combine_op(uLong crc1, uLong crc2, uLong op);
1891
/*
1892
Give the same result as crc32_combine(), using op in place of len2. op is
1893
is generated from len2 by crc32_combine_gen(). This will be faster than
1894
crc32_combine() if the generated op is used more than once.
1895
*/
1896
1897
1898
/* various hacks, don't look :) */
1899
1900
/* deflateInit and inflateInit are macros to allow checking the zlib version
1901
* and the compiler's view of z_stream:
1902
*/
1903
ZEXTERN int ZEXPORT deflateInit_(z_streamp strm, int level,
1904
const char *version, int stream_size);
1905
ZEXTERN int ZEXPORT inflateInit_(z_streamp strm,
1906
const char *version, int stream_size);
1907
ZEXTERN int ZEXPORT deflateInit2_(z_streamp strm, int level, int method,
1908
int windowBits, int memLevel,
1909
int strategy, const char *version,
1910
int stream_size);
1911
ZEXTERN int ZEXPORT inflateInit2_(z_streamp strm, int windowBits,
1912
const char *version, int stream_size);
1913
ZEXTERN int ZEXPORT inflateBackInit_(z_streamp strm, int windowBits,
1914
unsigned char FAR *window,
1915
const char *version,
1916
int stream_size);
1917
#ifdef Z_PREFIX_SET
1918
# define z_deflateInit(strm, level) \
1919
deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1920
# define z_inflateInit(strm) \
1921
inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1922
# define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1923
deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1924
(strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1925
# define z_inflateInit2(strm, windowBits) \
1926
inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1927
(int)sizeof(z_stream))
1928
# define z_inflateBackInit(strm, windowBits, window) \
1929
inflateBackInit_((strm), (windowBits), (window), \
1930
ZLIB_VERSION, (int)sizeof(z_stream))
1931
#else
1932
# define deflateInit(strm, level) \
1933
deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1934
# define inflateInit(strm) \
1935
inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1936
# define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1937
deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1938
(strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1939
# define inflateInit2(strm, windowBits) \
1940
inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1941
(int)sizeof(z_stream))
1942
# define inflateBackInit(strm, windowBits, window) \
1943
inflateBackInit_((strm), (windowBits), (window), \
1944
ZLIB_VERSION, (int)sizeof(z_stream))
1945
#endif
1946
1947
#ifndef Z_SOLO
1948
1949
/* gzgetc() macro and its supporting function and exposed data structure. Note
1950
* that the real internal state is much larger than the exposed structure.
1951
* This abbreviated structure exposes just enough for the gzgetc() macro. The
1952
* user should not mess with these exposed elements, since their names or
1953
* behavior could change in the future, perhaps even capriciously. They can
1954
* only be used by the gzgetc() macro. You have been warned.
1955
*/
1956
struct gzFile_s {
1957
unsigned have;
1958
unsigned char *next;
1959
z_off64_t pos;
1960
};
1961
ZEXTERN int ZEXPORT gzgetc_(gzFile file); /* backward compatibility */
1962
#ifdef Z_PREFIX_SET
1963
# undef z_gzgetc
1964
# define z_gzgetc(g) \
1965
((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1966
#else
1967
# define gzgetc(g) \
1968
((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1969
#endif
1970
1971
/* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1972
* change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1973
* both are true, the application gets the *64 functions, and the regular
1974
* functions are changed to 64 bits) -- in case these are set on systems
1975
* without large file support, _LFS64_LARGEFILE must also be true
1976
*/
1977
#ifdef Z_LARGE64
1978
ZEXTERN gzFile ZEXPORT gzopen64(const char *, const char *);
1979
ZEXTERN z_off64_t ZEXPORT gzseek64(gzFile, z_off64_t, int);
1980
ZEXTERN z_off64_t ZEXPORT gztell64(gzFile);
1981
ZEXTERN z_off64_t ZEXPORT gzoffset64(gzFile);
1982
ZEXTERN uLong ZEXPORT adler32_combine64(uLong, uLong, z_off64_t);
1983
ZEXTERN uLong ZEXPORT crc32_combine64(uLong, uLong, z_off64_t);
1984
ZEXTERN uLong ZEXPORT crc32_combine_gen64(z_off64_t);
1985
#endif
1986
1987
#if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
1988
# ifdef Z_PREFIX_SET
1989
# define z_gzopen z_gzopen64
1990
# define z_gzseek z_gzseek64
1991
# define z_gztell z_gztell64
1992
# define z_gzoffset z_gzoffset64
1993
# define z_adler32_combine z_adler32_combine64
1994
# define z_crc32_combine z_crc32_combine64
1995
# define z_crc32_combine_gen z_crc32_combine_gen64
1996
# else
1997
# define gzopen gzopen64
1998
# define gzseek gzseek64
1999
# define gztell gztell64
2000
# define gzoffset gzoffset64
2001
# define adler32_combine adler32_combine64
2002
# define crc32_combine crc32_combine64
2003
# define crc32_combine_gen crc32_combine_gen64
2004
# endif
2005
# ifndef Z_LARGE64
2006
ZEXTERN gzFile ZEXPORT gzopen64(const char *, const char *);
2007
ZEXTERN z_off_t ZEXPORT gzseek64(gzFile, z_off_t, int);
2008
ZEXTERN z_off_t ZEXPORT gztell64(gzFile);
2009
ZEXTERN z_off_t ZEXPORT gzoffset64(gzFile);
2010
ZEXTERN uLong ZEXPORT adler32_combine64(uLong, uLong, z_off64_t);
2011
ZEXTERN uLong ZEXPORT crc32_combine64(uLong, uLong, z_off64_t);
2012
ZEXTERN uLong ZEXPORT crc32_combine_gen64(z_off64_t);
2013
# endif
2014
#else
2015
ZEXTERN gzFile ZEXPORT gzopen(const char *, const char *);
2016
ZEXTERN z_off_t ZEXPORT gzseek(gzFile, z_off_t, int);
2017
ZEXTERN z_off_t ZEXPORT gztell(gzFile);
2018
ZEXTERN z_off_t ZEXPORT gzoffset(gzFile);
2019
ZEXTERN uLong ZEXPORT adler32_combine(uLong, uLong, z_off_t);
2020
ZEXTERN uLong ZEXPORT crc32_combine(uLong, uLong, z_off_t);
2021
ZEXTERN uLong ZEXPORT crc32_combine_gen(z_off_t);
2022
#endif
2023
2024
#else /* Z_SOLO */
2025
2026
ZEXTERN uLong ZEXPORT adler32_combine(uLong, uLong, z_off_t);
2027
ZEXTERN uLong ZEXPORT crc32_combine(uLong, uLong, z_off_t);
2028
ZEXTERN uLong ZEXPORT crc32_combine_gen(z_off_t);
2029
2030
#endif /* !Z_SOLO */
2031
2032
/* undocumented functions */
2033
ZEXTERN const char * ZEXPORT zError(int);
2034
ZEXTERN int ZEXPORT inflateSyncPoint(z_streamp);
2035
ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table(void);
2036
ZEXTERN int ZEXPORT inflateUndermine(z_streamp, int);
2037
ZEXTERN int ZEXPORT inflateValidate(z_streamp, int);
2038
ZEXTERN unsigned long ZEXPORT inflateCodesUsed(z_streamp);
2039
ZEXTERN int ZEXPORT inflateResetKeep(z_streamp);
2040
ZEXTERN int ZEXPORT deflateResetKeep(z_streamp);
2041
#if defined(_WIN32) && !defined(Z_SOLO)
2042
ZEXTERN gzFile ZEXPORT gzopen_w(const wchar_t *path,
2043
const char *mode);
2044
#endif
2045
#if defined(STDC) || defined(Z_HAVE_STDARG_H)
2046
# ifndef Z_SOLO
2047
ZEXTERN int ZEXPORTVA gzvprintf(gzFile file,
2048
const char *format,
2049
va_list va);
2050
# endif
2051
#endif
2052
2053
#ifdef __cplusplus
2054
}
2055
#endif
2056
2057
#endif /* ZLIB_H */
2058

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