0
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1 /* zlib.h -- interface of the 'zlib' general purpose compression library
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2 version 1.1.3, July 9th, 1998
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3
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4 Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler
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5
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6 This software is provided 'as-is', without any express or implied
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7 warranty. In no event will the authors be held liable for any damages
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8 arising from the use of this software.
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9
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10 Permission is granted to anyone to use this software for any purpose,
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11 including commercial applications, and to alter it and redistribute it
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12 freely, subject to the following restrictions:
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13
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14 1. The origin of this software must not be misrepresented; you must not
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15 claim that you wrote the original software. If you use this software
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16 in a product, an acknowledgment in the product documentation would be
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17 appreciated but is not required.
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18 2. Altered source versions must be plainly marked as such, and must not be
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19 misrepresented as being the original software.
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20 3. This notice may not be removed or altered from any source distribution.
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21
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22 Jean-loup Gailly Mark Adler
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23 jloup@gzip.org madler@alumni.caltech.edu
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24
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25
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26 The data format used by the zlib library is described by RFCs (Request for
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27 Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt
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28 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
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29 */
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30
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31 #ifndef _ZLIB_H
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32 #define _ZLIB_H
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33
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34 #include "zconf.h"
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35
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36 #ifdef __cplusplus
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37 extern "C" {
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38 #endif
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39
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40 #define ZLIB_VERSION "1.1.3"
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41
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42 /*
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43 The 'zlib' compression library provides in-memory compression and
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44 decompression functions, including integrity checks of the uncompressed
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45 data. This version of the library supports only one compression method
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46 (deflation) but other algorithms will be added later and will have the same
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47 stream interface.
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48
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49 Compression can be done in a single step if the buffers are large
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50 enough (for example if an input file is mmap'ed), or can be done by
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51 repeated calls of the compression function. In the latter case, the
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52 application must provide more input and/or consume the output
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53 (providing more output space) before each call.
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54
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55 The library also supports reading and writing files in gzip (.gz) format
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56 with an interface similar to that of stdio.
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57
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58 The library does not install any signal handler. The decoder checks
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59 the consistency of the compressed data, so the library should never
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60 crash even in case of corrupted input.
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61 */
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62
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63 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
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64 typedef void (*free_func) OF((voidpf opaque, voidpf address));
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65
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66 struct internal_state;
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67
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68 typedef struct z_stream_s {
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69 Bytef *next_in; /* next input byte */
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70 uInt avail_in; /* number of bytes available at next_in */
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71 uLong total_in; /* total nb of input bytes read so far */
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72
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73 Bytef *next_out; /* next output byte should be put there */
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74 uInt avail_out; /* remaining free space at next_out */
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75 uLong total_out; /* total nb of bytes output so far */
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76
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77 char *msg; /* last error message, NULL if no error */
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78 struct internal_state FAR *state; /* not visible by applications */
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79
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80 alloc_func zalloc; /* used to allocate the internal state */
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81 free_func zfree; /* used to free the internal state */
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82 voidpf opaque; /* private data object passed to zalloc and zfree */
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83
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84 int data_type; /* best guess about the data type: ascii or binary */
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85 uLong adler; /* adler32 value of the uncompressed data */
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86 uLong reserved; /* reserved for future use */
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87 } z_stream;
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88
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89 typedef z_stream FAR *z_streamp;
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90
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91 /*
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92 The application must update next_in and avail_in when avail_in has
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93 dropped to zero. It must update next_out and avail_out when avail_out
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94 has dropped to zero. The application must initialize zalloc, zfree and
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95 opaque before calling the init function. All other fields are set by the
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96 compression library and must not be updated by the application.
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97
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98 The opaque value provided by the application will be passed as the first
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99 parameter for calls of zalloc and zfree. This can be useful for custom
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100 memory management. The compression library attaches no meaning to the
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101 opaque value.
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102
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103 zalloc must return Z_NULL if there is not enough memory for the object.
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104 If zlib is used in a multi-threaded application, zalloc and zfree must be
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105 thread safe.
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106
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107 On 16-bit systems, the functions zalloc and zfree must be able to allocate
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108 exactly 65536 bytes, but will not be required to allocate more than this
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109 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
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110 pointers returned by zalloc for objects of exactly 65536 bytes *must*
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111 have their offset normalized to zero. The default allocation function
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112 provided by this library ensures this (see zutil.c). To reduce memory
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113 requirements and avoid any allocation of 64K objects, at the expense of
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114 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
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115
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116 The fields total_in and total_out can be used for statistics or
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117 progress reports. After compression, total_in holds the total size of
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118 the uncompressed data and may be saved for use in the decompressor
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119 (particularly if the decompressor wants to decompress everything in
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120 a single step).
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121 */
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122
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123 /* constants */
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124
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125 #define Z_NO_FLUSH 0
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126 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
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127 #define Z_SYNC_FLUSH 2
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128 #define Z_FULL_FLUSH 3
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129 #define Z_FINISH 4
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130 /* Allowed flush values; see deflate() below for details */
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131
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132 #define Z_OK 0
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133 #define Z_STREAM_END 1
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134 #define Z_NEED_DICT 2
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135 #define Z_ERRNO (-1)
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136 #define Z_STREAM_ERROR (-2)
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137 #define Z_DATA_ERROR (-3)
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138 #define Z_MEM_ERROR (-4)
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139 #define Z_BUF_ERROR (-5)
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140 #define Z_VERSION_ERROR (-6)
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141 /* Return codes for the compression/decompression functions. Negative
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142 * values are errors, positive values are used for special but normal events.
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143 */
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144
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145 #define Z_NO_COMPRESSION 0
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146 #define Z_BEST_SPEED 1
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147 #define Z_BEST_COMPRESSION 9
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148 #define Z_DEFAULT_COMPRESSION (-1)
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149 /* compression levels */
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150
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151 #define Z_FILTERED 1
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152 #define Z_HUFFMAN_ONLY 2
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153 #define Z_DEFAULT_STRATEGY 0
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154 /* compression strategy; see deflateInit2() below for details */
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155
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156 #define Z_BINARY 0
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157 #define Z_ASCII 1
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158 #define Z_UNKNOWN 2
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159 /* Possible values of the data_type field */
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160
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161 #define Z_DEFLATED 8
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162 /* The deflate compression method (the only one supported in this version) */
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163
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164 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
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165
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166 #define zlib_version zlibVersion()
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167 /* for compatibility with versions < 1.0.2 */
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168
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169 /* basic functions */
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170
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171 ZEXTERN const char * ZEXPORT zlibVersion OF((void));
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172 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
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173 If the first character differs, the library code actually used is
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174 not compatible with the zlib.h header file used by the application.
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175 This check is automatically made by deflateInit and inflateInit.
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176 */
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177
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178 /*
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179 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
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180
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181 Initializes the internal stream state for compression. The fields
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182 zalloc, zfree and opaque must be initialized before by the caller.
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183 If zalloc and zfree are set to Z_NULL, deflateInit updates them to
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184 use default allocation functions.
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185
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186 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
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187 1 gives best speed, 9 gives best compression, 0 gives no compression at
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188 all (the input data is simply copied a block at a time).
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189 Z_DEFAULT_COMPRESSION requests a default compromise between speed and
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190 compression (currently equivalent to level 6).
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191
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192 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
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193 enough memory, Z_STREAM_ERROR if level is not a valid compression level,
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194 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
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195 with the version assumed by the caller (ZLIB_VERSION).
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196 msg is set to null if there is no error message. deflateInit does not
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197 perform any compression: this will be done by deflate().
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198 */
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199
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200
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201 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
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202 /*
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203 deflate compresses as much data as possible, and stops when the input
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204 buffer becomes empty or the output buffer becomes full. It may introduce some
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205 output latency (reading input without producing any output) except when
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206 forced to flush.
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207
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208 The detailed semantics are as follows. deflate performs one or both of the
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209 following actions:
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210
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211 - Compress more input starting at next_in and update next_in and avail_in
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212 accordingly. If not all input can be processed (because there is not
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213 enough room in the output buffer), next_in and avail_in are updated and
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214 processing will resume at this point for the next call of deflate().
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215
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216 - Provide more output starting at next_out and update next_out and avail_out
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217 accordingly. This action is forced if the parameter flush is non zero.
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218 Forcing flush frequently degrades the compression ratio, so this parameter
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219 should be set only when necessary (in interactive applications).
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220 Some output may be provided even if flush is not set.
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221
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222 Before the call of deflate(), the application should ensure that at least
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223 one of the actions is possible, by providing more input and/or consuming
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224 more output, and updating avail_in or avail_out accordingly; avail_out
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225 should never be zero before the call. The application can consume the
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226 compressed output when it wants, for example when the output buffer is full
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227 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
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228 and with zero avail_out, it must be called again after making room in the
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229 output buffer because there might be more output pending.
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230
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231 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
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232 flushed to the output buffer and the output is aligned on a byte boundary, so
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233 that the decompressor can get all input data available so far. (In particular
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234 avail_in is zero after the call if enough output space has been provided
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235 before the call.) Flushing may degrade compression for some compression
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236 algorithms and so it should be used only when necessary.
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237
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238 If flush is set to Z_FULL_FLUSH, all output is flushed as with
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239 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
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240 restart from this point if previous compressed data has been damaged or if
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241 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
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242 the compression.
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243
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244 If deflate returns with avail_out == 0, this function must be called again
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245 with the same value of the flush parameter and more output space (updated
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246 avail_out), until the flush is complete (deflate returns with non-zero
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247 avail_out).
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248
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249 If the parameter flush is set to Z_FINISH, pending input is processed,
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250 pending output is flushed and deflate returns with Z_STREAM_END if there
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251 was enough output space; if deflate returns with Z_OK, this function must be
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252 called again with Z_FINISH and more output space (updated avail_out) but no
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253 more input data, until it returns with Z_STREAM_END or an error. After
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254 deflate has returned Z_STREAM_END, the only possible operations on the
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255 stream are deflateReset or deflateEnd.
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256
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257 Z_FINISH can be used immediately after deflateInit if all the compression
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258 is to be done in a single step. In this case, avail_out must be at least
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259 0.1% larger than avail_in plus 12 bytes. If deflate does not return
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260 Z_STREAM_END, then it must be called again as described above.
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261
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262 deflate() sets strm->adler to the adler32 checksum of all input read
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263 so far (that is, total_in bytes).
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264
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265 deflate() may update data_type if it can make a good guess about
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266 the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
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267 binary. This field is only for information purposes and does not affect
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268 the compression algorithm in any manner.
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269
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270 deflate() returns Z_OK if some progress has been made (more input
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271 processed or more output produced), Z_STREAM_END if all input has been
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272 consumed and all output has been produced (only when flush is set to
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273 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
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274 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
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275 (for example avail_in or avail_out was zero).
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276 */
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277
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278
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279 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
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280 /*
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281 All dynamically allocated data structures for this stream are freed.
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282 This function discards any unprocessed input and does not flush any
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283 pending output.
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284
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285 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
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286 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
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287 prematurely (some input or output was discarded). In the error case,
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288 msg may be set but then points to a static string (which must not be
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289 deallocated).
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290 */
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291
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292
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293 /*
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294 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
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295
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296 Initializes the internal stream state for decompression. The fields
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297 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
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298 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
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299 value depends on the compression method), inflateInit determines the
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300 compression method from the zlib header and allocates all data structures
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301 accordingly; otherwise the allocation will be deferred to the first call of
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302 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
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303 use default allocation functions.
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304
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305 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
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306 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
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307 version assumed by the caller. msg is set to null if there is no error
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308 message. inflateInit does not perform any decompression apart from reading
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309 the zlib header if present: this will be done by inflate(). (So next_in and
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310 avail_in may be modified, but next_out and avail_out are unchanged.)
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311 */
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312
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313
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314 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
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315 /*
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316 inflate decompresses as much data as possible, and stops when the input
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317 buffer becomes empty or the output buffer becomes full. It may some
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318 introduce some output latency (reading input without producing any output)
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319 except when forced to flush.
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320
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321 The detailed semantics are as follows. inflate performs one or both of the
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322 following actions:
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323
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324 - Decompress more input starting at next_in and update next_in and avail_in
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325 accordingly. If not all input can be processed (because there is not
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326 enough room in the output buffer), next_in is updated and processing
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327 will resume at this point for the next call of inflate().
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328
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329 - Provide more output starting at next_out and update next_out and avail_out
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330 accordingly. inflate() provides as much output as possible, until there
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331 is no more input data or no more space in the output buffer (see below
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332 about the flush parameter).
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333
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334 Before the call of inflate(), the application should ensure that at least
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335 one of the actions is possible, by providing more input and/or consuming
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336 more output, and updating the next_* and avail_* values accordingly.
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337 The application can consume the uncompressed output when it wants, for
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338 example when the output buffer is full (avail_out == 0), or after each
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339 call of inflate(). If inflate returns Z_OK and with zero avail_out, it
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340 must be called again after making room in the output buffer because there
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341 might be more output pending.
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342
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343 If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
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344 output as possible to the output buffer. The flushing behavior of inflate is
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345 not specified for values of the flush parameter other than Z_SYNC_FLUSH
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346 and Z_FINISH, but the current implementation actually flushes as much output
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347 as possible anyway.
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348
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349 inflate() should normally be called until it returns Z_STREAM_END or an
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350 error. However if all decompression is to be performed in a single step
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351 (a single call of inflate), the parameter flush should be set to
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352 Z_FINISH. In this case all pending input is processed and all pending
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353 output is flushed; avail_out must be large enough to hold all the
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354 uncompressed data. (The size of the uncompressed data may have been saved
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355 by the compressor for this purpose.) The next operation on this stream must
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356 be inflateEnd to deallocate the decompression state. The use of Z_FINISH
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357 is never required, but can be used to inform inflate that a faster routine
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358 may be used for the single inflate() call.
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359
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360 If a preset dictionary is needed at this point (see inflateSetDictionary
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361 below), inflate sets strm-adler to the adler32 checksum of the
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362 dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise
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363 it sets strm->adler to the adler32 checksum of all output produced
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364 so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
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365 an error code as described below. At the end of the stream, inflate()
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366 checks that its computed adler32 checksum is equal to that saved by the
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367 compressor and returns Z_STREAM_END only if the checksum is correct.
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368
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369 inflate() returns Z_OK if some progress has been made (more input processed
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370 or more output produced), Z_STREAM_END if the end of the compressed data has
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371 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
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372 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
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373 corrupted (input stream not conforming to the zlib format or incorrect
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374 adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
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375 (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
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376 enough memory, Z_BUF_ERROR if no progress is possible or if there was not
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377 enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
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378 case, the application may then call inflateSync to look for a good
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379 compression block.
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380 */
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381
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382
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383 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
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384 /*
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385 All dynamically allocated data structures for this stream are freed.
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386 This function discards any unprocessed input and does not flush any
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387 pending output.
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388
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389 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
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390 was inconsistent. In the error case, msg may be set but then points to a
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391 static string (which must not be deallocated).
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392 */
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393
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394 /* Advanced functions */
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395
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396 /*
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397 The following functions are needed only in some special applications.
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398 */
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399
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400 /*
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401 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
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402 int level,
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403 int method,
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404 int windowBits,
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405 int memLevel,
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406 int strategy));
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407
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408 This is another version of deflateInit with more compression options. The
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409 fields next_in, zalloc, zfree and opaque must be initialized before by
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410 the caller.
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411
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412 The method parameter is the compression method. It must be Z_DEFLATED in
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413 this version of the library.
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414
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415 The windowBits parameter is the base two logarithm of the window size
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416 (the size of the history buffer). It should be in the range 8..15 for this
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417 version of the library. Larger values of this parameter result in better
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418 compression at the expense of memory usage. The default value is 15 if
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419 deflateInit is used instead.
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420
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421 The memLevel parameter specifies how much memory should be allocated
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422 for the internal compression state. memLevel=1 uses minimum memory but
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423 is slow and reduces compression ratio; memLevel=9 uses maximum memory
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424 for optimal speed. The default value is 8. See zconf.h for total memory
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425 usage as a function of windowBits and memLevel.
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426
|
|
427 The strategy parameter is used to tune the compression algorithm. Use the
|
|
428 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
|
|
429 filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
|
|
430 string match). Filtered data consists mostly of small values with a
|
|
431 somewhat random distribution. In this case, the compression algorithm is
|
|
432 tuned to compress them better. The effect of Z_FILTERED is to force more
|
|
433 Huffman coding and less string matching; it is somewhat intermediate
|
|
434 between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
|
|
435 the compression ratio but not the correctness of the compressed output even
|
|
436 if it is not set appropriately.
|
|
437
|
|
438 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
|
|
439 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
|
|
440 method). msg is set to null if there is no error message. deflateInit2 does
|
|
441 not perform any compression: this will be done by deflate().
|
|
442 */
|
|
443
|
|
444 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
|
|
445 const Bytef *dictionary,
|
|
446 uInt dictLength));
|
|
447 /*
|
|
448 Initializes the compression dictionary from the given byte sequence
|
|
449 without producing any compressed output. This function must be called
|
|
450 immediately after deflateInit, deflateInit2 or deflateReset, before any
|
|
451 call of deflate. The compressor and decompressor must use exactly the same
|
|
452 dictionary (see inflateSetDictionary).
|
|
453
|
|
454 The dictionary should consist of strings (byte sequences) that are likely
|
|
455 to be encountered later in the data to be compressed, with the most commonly
|
|
456 used strings preferably put towards the end of the dictionary. Using a
|
|
457 dictionary is most useful when the data to be compressed is short and can be
|
|
458 predicted with good accuracy; the data can then be compressed better than
|
|
459 with the default empty dictionary.
|
|
460
|
|
461 Depending on the size of the compression data structures selected by
|
|
462 deflateInit or deflateInit2, a part of the dictionary may in effect be
|
|
463 discarded, for example if the dictionary is larger than the window size in
|
|
464 deflate or deflate2. Thus the strings most likely to be useful should be
|
|
465 put at the end of the dictionary, not at the front.
|
|
466
|
|
467 Upon return of this function, strm->adler is set to the Adler32 value
|
|
468 of the dictionary; the decompressor may later use this value to determine
|
|
469 which dictionary has been used by the compressor. (The Adler32 value
|
|
470 applies to the whole dictionary even if only a subset of the dictionary is
|
|
471 actually used by the compressor.)
|
|
472
|
|
473 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
|
|
474 parameter is invalid (such as NULL dictionary) or the stream state is
|
|
475 inconsistent (for example if deflate has already been called for this stream
|
|
476 or if the compression method is bsort). deflateSetDictionary does not
|
|
477 perform any compression: this will be done by deflate().
|
|
478 */
|
|
479
|
|
480 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
|
|
481 z_streamp source));
|
|
482 /*
|
|
483 Sets the destination stream as a complete copy of the source stream.
|
|
484
|
|
485 This function can be useful when several compression strategies will be
|
|
486 tried, for example when there are several ways of pre-processing the input
|
|
487 data with a filter. The streams that will be discarded should then be freed
|
|
488 by calling deflateEnd. Note that deflateCopy duplicates the internal
|
|
489 compression state which can be quite large, so this strategy is slow and
|
|
490 can consume lots of memory.
|
|
491
|
|
492 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
|
|
493 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
|
|
494 (such as zalloc being NULL). msg is left unchanged in both source and
|
|
495 destination.
|
|
496 */
|
|
497
|
|
498 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
|
|
499 /*
|
|
500 This function is equivalent to deflateEnd followed by deflateInit,
|
|
501 but does not free and reallocate all the internal compression state.
|
|
502 The stream will keep the same compression level and any other attributes
|
|
503 that may have been set by deflateInit2.
|
|
504
|
|
505 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
|
|
506 stream state was inconsistent (such as zalloc or state being NULL).
|
|
507 */
|
|
508
|
|
509 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
|
|
510 int level,
|
|
511 int strategy));
|
|
512 /*
|
|
513 Dynamically update the compression level and compression strategy. The
|
|
514 interpretation of level and strategy is as in deflateInit2. This can be
|
|
515 used to switch between compression and straight copy of the input data, or
|
|
516 to switch to a different kind of input data requiring a different
|
|
517 strategy. If the compression level is changed, the input available so far
|
|
518 is compressed with the old level (and may be flushed); the new level will
|
|
519 take effect only at the next call of deflate().
|
|
520
|
|
521 Before the call of deflateParams, the stream state must be set as for
|
|
522 a call of deflate(), since the currently available input may have to
|
|
523 be compressed and flushed. In particular, strm->avail_out must be non-zero.
|
|
524
|
|
525 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
|
|
526 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
|
|
527 if strm->avail_out was zero.
|
|
528 */
|
|
529
|
|
530 /*
|
|
531 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
|
|
532 int windowBits));
|
|
533
|
|
534 This is another version of inflateInit with an extra parameter. The
|
|
535 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
|
|
536 before by the caller.
|
|
537
|
|
538 The windowBits parameter is the base two logarithm of the maximum window
|
|
539 size (the size of the history buffer). It should be in the range 8..15 for
|
|
540 this version of the library. The default value is 15 if inflateInit is used
|
|
541 instead. If a compressed stream with a larger window size is given as
|
|
542 input, inflate() will return with the error code Z_DATA_ERROR instead of
|
|
543 trying to allocate a larger window.
|
|
544
|
|
545 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
|
|
546 memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
|
|
547 memLevel). msg is set to null if there is no error message. inflateInit2
|
|
548 does not perform any decompression apart from reading the zlib header if
|
|
549 present: this will be done by inflate(). (So next_in and avail_in may be
|
|
550 modified, but next_out and avail_out are unchanged.)
|
|
551 */
|
|
552
|
|
553 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
|
|
554 const Bytef *dictionary,
|
|
555 uInt dictLength));
|
|
556 /*
|
|
557 Initializes the decompression dictionary from the given uncompressed byte
|
|
558 sequence. This function must be called immediately after a call of inflate
|
|
559 if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
|
|
560 can be determined from the Adler32 value returned by this call of
|
|
561 inflate. The compressor and decompressor must use exactly the same
|
|
562 dictionary (see deflateSetDictionary).
|
|
563
|
|
564 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
|
|
565 parameter is invalid (such as NULL dictionary) or the stream state is
|
|
566 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
|
|
567 expected one (incorrect Adler32 value). inflateSetDictionary does not
|
|
568 perform any decompression: this will be done by subsequent calls of
|
|
569 inflate().
|
|
570 */
|
|
571
|
|
572 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
|
|
573 /*
|
|
574 Skips invalid compressed data until a full flush point (see above the
|
|
575 description of deflate with Z_FULL_FLUSH) can be found, or until all
|
|
576 available input is skipped. No output is provided.
|
|
577
|
|
578 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
|
|
579 if no more input was provided, Z_DATA_ERROR if no flush point has been found,
|
|
580 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
|
|
581 case, the application may save the current current value of total_in which
|
|
582 indicates where valid compressed data was found. In the error case, the
|
|
583 application may repeatedly call inflateSync, providing more input each time,
|
|
584 until success or end of the input data.
|
|
585 */
|
|
586
|
|
587 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
|
|
588 /*
|
|
589 This function is equivalent to inflateEnd followed by inflateInit,
|
|
590 but does not free and reallocate all the internal decompression state.
|
|
591 The stream will keep attributes that may have been set by inflateInit2.
|
|
592
|
|
593 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
|
|
594 stream state was inconsistent (such as zalloc or state being NULL).
|
|
595 */
|
|
596
|
|
597
|
|
598 /* utility functions */
|
|
599
|
|
600 /*
|
|
601 The following utility functions are implemented on top of the
|
|
602 basic stream-oriented functions. To simplify the interface, some
|
|
603 default options are assumed (compression level and memory usage,
|
|
604 standard memory allocation functions). The source code of these
|
|
605 utility functions can easily be modified if you need special options.
|
|
606 */
|
|
607
|
|
608 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
|
|
609 const Bytef *source, uLong sourceLen));
|
|
610 /*
|
|
611 Compresses the source buffer into the destination buffer. sourceLen is
|
|
612 the byte length of the source buffer. Upon entry, destLen is the total
|
|
613 size of the destination buffer, which must be at least 0.1% larger than
|
|
614 sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
|
|
615 compressed buffer.
|
|
616 This function can be used to compress a whole file at once if the
|
|
617 input file is mmap'ed.
|
|
618 compress returns Z_OK if success, Z_MEM_ERROR if there was not
|
|
619 enough memory, Z_BUF_ERROR if there was not enough room in the output
|
|
620 buffer.
|
|
621 */
|
|
622
|
|
623 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
|
|
624 const Bytef *source, uLong sourceLen,
|
|
625 int level));
|
|
626 /*
|
|
627 Compresses the source buffer into the destination buffer. The level
|
|
628 parameter has the same meaning as in deflateInit. sourceLen is the byte
|
|
629 length of the source buffer. Upon entry, destLen is the total size of the
|
|
630 destination buffer, which must be at least 0.1% larger than sourceLen plus
|
|
631 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
|
|
632
|
|
633 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
|
|
634 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
|
|
635 Z_STREAM_ERROR if the level parameter is invalid.
|
|
636 */
|
|
637
|
|
638 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
|
|
639 const Bytef *source, uLong sourceLen));
|
|
640 /*
|
|
641 Decompresses the source buffer into the destination buffer. sourceLen is
|
|
642 the byte length of the source buffer. Upon entry, destLen is the total
|
|
643 size of the destination buffer, which must be large enough to hold the
|
|
644 entire uncompressed data. (The size of the uncompressed data must have
|
|
645 been saved previously by the compressor and transmitted to the decompressor
|
|
646 by some mechanism outside the scope of this compression library.)
|
|
647 Upon exit, destLen is the actual size of the compressed buffer.
|
|
648 This function can be used to decompress a whole file at once if the
|
|
649 input file is mmap'ed.
|
|
650
|
|
651 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
|
|
652 enough memory, Z_BUF_ERROR if there was not enough room in the output
|
|
653 buffer, or Z_DATA_ERROR if the input data was corrupted.
|
|
654 */
|
|
655
|
|
656
|
|
657 typedef voidp gzFile;
|
|
658
|
|
659 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
|
|
660 /*
|
|
661 Opens a gzip (.gz) file for reading or writing. The mode parameter
|
|
662 is as in fopen ("rb" or "wb") but can also include a compression level
|
|
663 ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
|
|
664 Huffman only compression as in "wb1h". (See the description
|
|
665 of deflateInit2 for more information about the strategy parameter.)
|
|
666
|
|
667 gzopen can be used to read a file which is not in gzip format; in this
|
|
668 case gzread will directly read from the file without decompression.
|
|
669
|
|
670 gzopen returns NULL if the file could not be opened or if there was
|
|
671 insufficient memory to allocate the (de)compression state; errno
|
|
672 can be checked to distinguish the two cases (if errno is zero, the
|
|
673 zlib error is Z_MEM_ERROR). */
|
|
674
|
|
675 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
|
|
676 /*
|
|
677 gzdopen() associates a gzFile with the file descriptor fd. File
|
|
678 descriptors are obtained from calls like open, dup, creat, pipe or
|
|
679 fileno (in the file has been previously opened with fopen).
|
|
680 The mode parameter is as in gzopen.
|
|
681 The next call of gzclose on the returned gzFile will also close the
|
|
682 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
|
|
683 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
|
|
684 gzdopen returns NULL if there was insufficient memory to allocate
|
|
685 the (de)compression state.
|
|
686 */
|
|
687
|
|
688 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
|
|
689 /*
|
|
690 Dynamically update the compression level or strategy. See the description
|
|
691 of deflateInit2 for the meaning of these parameters.
|
|
692 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
|
|
693 opened for writing.
|
|
694 */
|
|
695
|
|
696 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
|
|
697 /*
|
|
698 Reads the given number of uncompressed bytes from the compressed file.
|
|
699 If the input file was not in gzip format, gzread copies the given number
|
|
700 of bytes into the buffer.
|
|
701 gzread returns the number of uncompressed bytes actually read (0 for
|
|
702 end of file, -1 for error). */
|
|
703
|
|
704 ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
|
|
705 const voidp buf, unsigned len));
|
|
706 /*
|
|
707 Writes the given number of uncompressed bytes into the compressed file.
|
|
708 gzwrite returns the number of uncompressed bytes actually written
|
|
709 (0 in case of error).
|
|
710 */
|
|
711
|
|
712 ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...));
|
|
713 /*
|
|
714 Converts, formats, and writes the args to the compressed file under
|
|
715 control of the format string, as in fprintf. gzprintf returns the number of
|
|
716 uncompressed bytes actually written (0 in case of error).
|
|
717 */
|
|
718
|
|
719 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
|
|
720 /*
|
|
721 Writes the given null-terminated string to the compressed file, excluding
|
|
722 the terminating null character.
|
|
723 gzputs returns the number of characters written, or -1 in case of error.
|
|
724 */
|
|
725
|
|
726 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
|
|
727 /*
|
|
728 Reads bytes from the compressed file until len-1 characters are read, or
|
|
729 a newline character is read and transferred to buf, or an end-of-file
|
|
730 condition is encountered. The string is then terminated with a null
|
|
731 character.
|
|
732 gzgets returns buf, or Z_NULL in case of error.
|
|
733 */
|
|
734
|
|
735 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
|
|
736 /*
|
|
737 Writes c, converted to an unsigned char, into the compressed file.
|
|
738 gzputc returns the value that was written, or -1 in case of error.
|
|
739 */
|
|
740
|
|
741 ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
|
|
742 /*
|
|
743 Reads one byte from the compressed file. gzgetc returns this byte
|
|
744 or -1 in case of end of file or error.
|
|
745 */
|
|
746
|
|
747 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
|
|
748 /*
|
|
749 Flushes all pending output into the compressed file. The parameter
|
|
750 flush is as in the deflate() function. The return value is the zlib
|
|
751 error number (see function gzerror below). gzflush returns Z_OK if
|
|
752 the flush parameter is Z_FINISH and all output could be flushed.
|
|
753 gzflush should be called only when strictly necessary because it can
|
|
754 degrade compression.
|
|
755 */
|
|
756
|
|
757 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
|
|
758 z_off_t offset, int whence));
|
|
759 /*
|
|
760 Sets the starting position for the next gzread or gzwrite on the
|
|
761 given compressed file. The offset represents a number of bytes in the
|
|
762 uncompressed data stream. The whence parameter is defined as in lseek(2);
|
|
763 the value SEEK_END is not supported.
|
|
764 If the file is opened for reading, this function is emulated but can be
|
|
765 extremely slow. If the file is opened for writing, only forward seeks are
|
|
766 supported; gzseek then compresses a sequence of zeroes up to the new
|
|
767 starting position.
|
|
768
|
|
769 gzseek returns the resulting offset location as measured in bytes from
|
|
770 the beginning of the uncompressed stream, or -1 in case of error, in
|
|
771 particular if the file is opened for writing and the new starting position
|
|
772 would be before the current position.
|
|
773 */
|
|
774
|
|
775 ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
|
|
776 /*
|
|
777 Rewinds the given file. This function is supported only for reading.
|
|
778
|
|
779 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
|
|
780 */
|
|
781
|
|
782 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
|
|
783 /*
|
|
784 Returns the starting position for the next gzread or gzwrite on the
|
|
785 given compressed file. This position represents a number of bytes in the
|
|
786 uncompressed data stream.
|
|
787
|
|
788 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
|
|
789 */
|
|
790
|
|
791 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
|
|
792 /*
|
|
793 Returns 1 when EOF has previously been detected reading the given
|
|
794 input stream, otherwise zero.
|
|
795 */
|
|
796
|
|
797 ZEXTERN int ZEXPORT gzclose OF((gzFile file));
|
|
798 /*
|
|
799 Flushes all pending output if necessary, closes the compressed file
|
|
800 and deallocates all the (de)compression state. The return value is the zlib
|
|
801 error number (see function gzerror below).
|
|
802 */
|
|
803
|
|
804 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
|
|
805 /*
|
|
806 Returns the error message for the last error which occurred on the
|
|
807 given compressed file. errnum is set to zlib error number. If an
|
|
808 error occurred in the file system and not in the compression library,
|
|
809 errnum is set to Z_ERRNO and the application may consult errno
|
|
810 to get the exact error code.
|
|
811 */
|
|
812
|
|
813 /* checksum functions */
|
|
814
|
|
815 /*
|
|
816 These functions are not related to compression but are exported
|
|
817 anyway because they might be useful in applications using the
|
|
818 compression library.
|
|
819 */
|
|
820
|
|
821 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
|
|
822
|
|
823 /*
|
|
824 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
|
|
825 return the updated checksum. If buf is NULL, this function returns
|
|
826 the required initial value for the checksum.
|
|
827 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
|
|
828 much faster. Usage example:
|
|
829
|
|
830 uLong adler = adler32(0L, Z_NULL, 0);
|
|
831
|
|
832 while (read_buffer(buffer, length) != EOF) {
|
|
833 adler = adler32(adler, buffer, length);
|
|
834 }
|
|
835 if (adler != original_adler) error();
|
|
836 */
|
|
837
|
|
838 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
|
|
839 /*
|
|
840 Update a running crc with the bytes buf[0..len-1] and return the updated
|
|
841 crc. If buf is NULL, this function returns the required initial value
|
|
842 for the crc. Pre- and post-conditioning (one's complement) is performed
|
|
843 within this function so it shouldn't be done by the application.
|
|
844 Usage example:
|
|
845
|
|
846 uLong crc = crc32(0L, Z_NULL, 0);
|
|
847
|
|
848 while (read_buffer(buffer, length) != EOF) {
|
|
849 crc = crc32(crc, buffer, length);
|
|
850 }
|
|
851 if (crc != original_crc) error();
|
|
852 */
|
|
853
|
|
854
|
|
855 /* various hacks, don't look :) */
|
|
856
|
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857 /* deflateInit and inflateInit are macros to allow checking the zlib version
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858 * and the compiler's view of z_stream:
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859 */
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860 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
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861 const char *version, int stream_size));
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862 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
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863 const char *version, int stream_size));
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864 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
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865 int windowBits, int memLevel,
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866 int strategy, const char *version,
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867 int stream_size));
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868 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
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869 const char *version, int stream_size));
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870 #define deflateInit(strm, level) \
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871 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
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872 #define inflateInit(strm) \
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873 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
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874 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
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875 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
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876 (strategy), ZLIB_VERSION, sizeof(z_stream))
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877 #define inflateInit2(strm, windowBits) \
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878 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
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879
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880
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881 #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
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882 struct internal_state {int dummy;}; /* hack for buggy compilers */
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883 #endif
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884
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885 ZEXTERN const char * ZEXPORT zError OF((int err));
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886 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z));
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887 ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void));
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888
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889 #ifdef __cplusplus
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890 }
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891 #endif
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892
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893 #endif /* _ZLIB_H */
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