ceph/src/boost/boost/beast/zlib/zlib.hpp

   1 //
   2 // Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
   3 //
   4 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   5 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // Official repository: https://github.com/boostorg/beast
   8 //
   9 // This is a derivative work based on Zlib, copyright below:
  10 /*
  11     Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler
  12
  13     This software is provided 'as-is', without any express or implied
  14     warranty.  In no event will the authors be held liable for any damages
  15     arising from the use of this software.
  16
  17     Permission is granted to anyone to use this software for any purpose,
  18     including commercial applications, and to alter it and redistribute it
  19     freely, subject to the following restrictions:
  20
  21     1. The origin of this software must not be misrepresented; you must not
  22        claim that you wrote the original software. If you use this software
  23        in a product, an acknowledgment in the product documentation would be
  24        appreciated but is not required.
  25     2. Altered source versions must be plainly marked as such, and must not be
  26        misrepresented as being the original software.
  27     3. This notice may not be removed or altered from any source distribution.
  28
  29     Jean-loup Gailly        Mark Adler
  30     jloup@gzip.org          madler@alumni.caltech.edu
  31
  32     The data format used by the zlib library is described by RFCs (Request for
  33     Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
  34     (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
  35 */
  36
  37 #ifndef BOOST_BEAST_ZLIB_ZLIB_HPP
  38 #define BOOST_BEAST_ZLIB_ZLIB_HPP
  39
  40 #include <boost/beast/core/detail/config.hpp>
  41 #include <cstdint>
  42 #include <cstdlib>
  43
  44 namespace boost {
  45 namespace beast {
  46 namespace zlib {
  47
  48 #if !defined(__MACTYPES__)
  49 using Byte = unsigned char; // 8 bits
  50 #endif
  51 using uInt = unsigned int;  // 16 bits or more
  52
  53 /* Possible values of the data_type field (though see inflate()) */
  54 enum kind
  55 {
  56     binary    = 0,
  57     text      = 1,
  58     unknown   = 2
  59 };
  60
  61 /** Deflate codec parameters.
  62
  63     Objects of this type are filled in by callers and provided to the
  64     deflate codec to define the input and output areas for the next
  65     compress or decompress operation.
  66
  67     The application must update next_in and avail_in when avail_in has dropped
  68     to zero.  It must update next_out and avail_out when avail_out has dropped
  69     to zero.  The application must initialize zalloc, zfree and opaque before
  70     calling the init function.  All other fields are set by the compression
  71     library and must not be updated by the application.
  72
  73     The fields total_in and total_out can be used for statistics or progress
  74     reports.  After compression, total_in holds the total size of the
  75     uncompressed data and may be saved for use in the decompressor (particularly
  76     if the decompressor wants to decompress everything in a single step).
  77 */
  78 struct z_params
  79 {
  80     /** A pointer to the next input byte.
  81
  82         If there is no more input, this may be set to `nullptr`.
  83     */
  84     void const* next_in;
  85
  86     /** The number of bytes of input available at `next_in`.
  87
  88         If there is no more input, this should be set to zero.
  89     */
  90     std::size_t avail_in;
  91
  92     /** The total number of input bytes read so far.
  93     */
  94     std::size_t total_in = 0;
  95
  96     /** A pointer to the next output byte.
  97     */
  98     void* next_out;
  99
 100     /** The remaining bytes of space at `next_out`.
 101     */
 102     std::size_t avail_out;
 103
 104     /** The total number of bytes output so far.
 105     */
 106     std::size_t total_out = 0;
 107
 108     int data_type = unknown;  // best guess about the data type: binary or text
 109 };
 110
 111 /** Flush option.
 112 */
 113 enum class Flush
 114 {
 115     // order matters
 116
 117     none,
 118     block,
 119     partial,
 120     sync,
 121     full,
 122     finish,
 123     trees
 124 };
 125
 126 /* compression levels */
 127 enum compression
 128 {
 129     none        =  0,
 130     best_speed            =  1,
 131     best_size      =  9,
 132     default_size   = -1
 133 };
 134
 135 /** Compression strategy.
 136
 137     These are used when compressing streams.
 138 */
 139 enum class Strategy
 140 {
 141     /** Default strategy.
 142
 143         This is suitable for general purpose compression, and works
 144         well in the majority of cases.
 145     */
 146     normal,
 147
 148     /** Filtered strategy.
 149
 150         This strategy should be used when the data be compressed
 151         is produced by a filter or predictor.
 152     */
 153     filtered,
 154
 155     /** Huffman-only strategy.
 156
 157         This strategy only performs Huffman encoding, without doing
 158         any string matching.
 159     */
 160     huffman,
 161
 162     /** Run Length Encoding strategy.
 163
 164         This strategy limits match distances to one, making it
 165         equivalent to run length encoding. This can give better
 166         performance for things like PNG image data.
 167     */
 168     rle,
 169
 170     /** Fixed table strategy.
 171
 172         This strategy prevents the use of dynamic Huffman codes,
 173         allowing for a simpler decoder for special applications.
 174     */
 175     fixed
 176 };
 177
 178 } // zlib
 179 } // beast
 180 } // boost
 181
 182 #endif
 183