include/linux/zlib.h

1 /* zlib.h -- interface of the 'zlib' general purpose compression library
53      The 'zlib' compression library provides in-memory compression and
55   data.  This version of the library supports only one compression method
59      Compression can be done in a single step if the buffers are large
61   repeated calls of the compression function.  In the latter case, the
74   file compression on file systems, has a larger header than zlib to maintain
110    compression library and must not be updated by the application.
114    memory management. The compression library attaches no meaning to the
128    compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
131    progress reports. After compression, total_in holds the total size of
157 /* Return codes for the compression/decompression functions. Negative
165 /* compression levels */
170 /* compression strategy; see deflateInit2() below for details */
178 /* The deflate compression method (the only one supported in this version) */
203      Initializes the internal stream state for compression. The fields
208      The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
209    1 gives best speed, 9 gives best compression, 0 gives no compression at
212    compression (currently equivalent to level 6).
215    enough memory, Z_STREAM_ERROR if level is not a valid compression level,
219    perform any compression: this will be done by deflate().
240     Forcing flush frequently degrades the compression ratio, so this parameter
257   before the call.)  Flushing may degrade compression for some compression
261   Z_SYNC_FLUSH, and the compression state is reset so that decompression can
264   the compression.
279     Z_FINISH can be used immediately after deflateInit if all the compression
290   the compression algorithm in any manner.
328    value depends on the compression method), inflateInit determines the
329    compression method from the zlib header and allocates all data structures
437   call inflateSync() to look for a good compression block if a partial recovery
467      This is another version of deflateInit with more compression options. The
471      The method parameter is the compression method. It must be Z_DEFLATED in
477    compression at the expense of memory usage. The default value is 15 if
481    for the internal compression state. memLevel=1 uses minimum memory but
482    is slow and reduces compression ratio; memLevel=9 uses maximum memory
486      The strategy parameter is used to tune the compression algorithm. Use the
490    somewhat random distribution. In this case, the compression algorithm is
494    the compression ratio but not the correctness of the compressed output even
500    not perform any compression: this will be done by deflate().
506    but does not free and reallocate all the internal compression state.
507    The stream will keep the same compression level and any other attributes