ceph/src/Beast/include/beast/zlib/zlib.hpp

   1 //
   2 // Copyright (c) 2013-2017 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 // This is a derivative work based on Zlib, copyright below:
   8 /*
   9     Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler
  10
  11     This software is provided 'as-is', without any express or implied
  12     warranty.  In no event will the authors be held liable for any damages
  13     arising from the use of this software.
  14
  15     Permission is granted to anyone to use this software for any purpose,
  16     including commercial applications, and to alter it and redistribute it
  17     freely, subject to the following restrictions:
  18
  19     1. The origin of this software must not be misrepresented; you must not
  20        claim that you wrote the original software. If you use this software
  21        in a product, an acknowledgment in the product documentation would be
  22        appreciated but is not required.
  23     2. Altered source versions must be plainly marked as such, and must not be
  24        misrepresented as being the original software.
  25     3. This notice may not be removed or altered from any source distribution.
  26
  27     Jean-loup Gailly        Mark Adler
  28     jloup@gzip.org          madler@alumni.caltech.edu
  29
  30     The data format used by the zlib library is described by RFCs (Request for
  31     Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
  32     (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
  33 */
  34
  35 #ifndef BEAST_ZLIB_ZLIB_HPP
  36 #define BEAST_ZLIB_ZLIB_HPP
  37
  38 #include <beast/config.hpp>
  39 #include <cstdint>
  40 #include <cstdlib>
  41
  42 namespace beast {
  43 namespace zlib {
  44
  45 #if !defined(__MACTYPES__)
  46 typedef unsigned char  Byte;  /* 8 bits */
  47 #endif
  48 typedef unsigned int   uInt;  /* 16 bits or more */
  49
  50 /* Possible values of the data_type field (though see inflate()) */
  51 enum z_Type
  52 {
  53     Z_BINARY    = 0,
  54     Z_TEXT      = 1,
  55     Z_UNKNOWN   = 2
  56 };
  57
  58 /** Deflate codec parameters.
  59
  60     Objects of this type are filled in by callers and provided to the
  61     deflate codec to define the input and output areas for the next
  62     compress or decompress operation.
  63
  64     The application must update next_in and avail_in when avail_in has dropped
  65     to zero.  It must update next_out and avail_out when avail_out has dropped
  66     to zero.  The application must initialize zalloc, zfree and opaque before
  67     calling the init function.  All other fields are set by the compression
  68     library and must not be updated by the application.
  69
  70     The fields total_in and total_out can be used for statistics or progress
  71     reports.  After compression, total_in holds the total size of the
  72     uncompressed data and may be saved for use in the decompressor (particularly
  73     if the decompressor wants to decompress everything in a single step).
  74 */
  75 struct z_params
  76 {
  77     /** A pointer to the next input byte.
  78
  79         If there is no more input, this may be set to `nullptr`.
  80     */
  81     void const* next_in;
  82
  83     /** The number of bytes of input available at `next_in`.
  84
  85         If there is no more input, this should be set to zero.
  86     */
  87     std::size_t avail_in;
  88
  89     /** The total number of input bytes read so far.
  90     */
  91     std::size_t total_in = 0;
  92
  93     /** A pointer to the next output byte.
  94     */
  95     void* next_out;
  96
  97     /** The remaining bytes of space at `next_out`.
  98     */
  99     std::size_t avail_out;
 100
 101     /** The total number of bytes output so far.
 102     */
 103     std::size_t total_out = 0;
 104
 105     int data_type = Z_UNKNOWN;  // best guess about the data type: binary or text
 106 };
 107
 108 /** Flush option.
 109 */
 110 enum class Flush
 111 {
 112     // order matters
 113
 114     none,
 115     block,
 116     partial,
 117     sync,
 118     full,
 119     finish,
 120     trees
 121 };
 122
 123 /* compression levels */
 124 enum z_Compression
 125 {
 126     Z_NO_COMPRESSION        =  0,
 127     Z_BEST_SPEED            =  1,
 128     Z_BEST_COMPRESSION      =  9,
 129     Z_DEFAULT_COMPRESSION   = -1
 130 };
 131
 132 /** Compression strategy.
 133
 134     These are used when compressing streams.
 135 */
 136 enum class Strategy
 137 {
 138     /** Default strategy.
 139
 140         This is suitable for general purpose compression, and works
 141         well in the majority of cases.
 142     */
 143     normal,
 144
 145     /** Filtered strategy.
 146
 147         This strategy should be used when the data be compressed
 148         is produced by a filter or predictor.
 149     */
 150     filtered,
 151
 152     /** Huffman-only strategy.
 153
 154         This strategy only performs Huffman encoding, without doing
 155         any string matching.
 156     */
 157     huffman,
 158
 159     /** Run Length Encoding strategy.
 160
 161         This strategy limits match distances to one, making it
 162         equivalent to run length encoding. This can give better
 163         performance for things like PNG image data.
 164     */
 165     rle,
 166
 167     /** Fixed table strategy.
 168
 169         This strategy prevents the use of dynamic Huffman codes,
 170         allowing for a simpler decoder for special applications.
 171     */
 172     fixed
 173 };
 174
 175 } // zlib
 176 } // beast
 177
 178 #endif
 179