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422 | giacomo | 1 | /* zlib.h -- interface of the 'zlib' general purpose compression library |
2 | version 1.1.3, July 9th, 1998 |
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3 | |||
4 | Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler |
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5 | |||
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 | |||
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 | |||
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 | |||
22 | Jean-loup Gailly Mark Adler |
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23 | jloup@gzip.org madler@alumni.caltech.edu |
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24 | |||
25 | |||
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 | |||
31 | #ifndef _ZLIB_H |
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32 | #define _ZLIB_H |
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33 | |||
34 | #include <linux/zconf.h> |
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35 | |||
36 | #define ZLIB_VERSION "1.1.3" |
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37 | |||
38 | /* |
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39 | The 'zlib' compression library provides in-memory compression and |
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40 | decompression functions, including integrity checks of the uncompressed |
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41 | data. This version of the library supports only one compression method |
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42 | (deflation) but other algorithms will be added later and will have the same |
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43 | stream interface. |
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44 | |||
45 | Compression can be done in a single step if the buffers are large |
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46 | enough (for example if an input file is mmap'ed), or can be done by |
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47 | repeated calls of the compression function. In the latter case, the |
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48 | application must provide more input and/or consume the output |
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49 | (providing more output space) before each call. |
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50 | |||
51 | The library also supports reading and writing files in gzip (.gz) format |
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52 | with an interface similar to that of stdio. |
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53 | |||
54 | The library does not install any signal handler. The decoder checks |
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55 | the consistency of the compressed data, so the library should never |
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56 | crash even in case of corrupted input. |
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57 | */ |
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58 | |||
59 | struct internal_state; |
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60 | |||
61 | typedef struct z_stream_s { |
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62 | Byte *next_in; /* next input byte */ |
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63 | uInt avail_in; /* number of bytes available at next_in */ |
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64 | uLong total_in; /* total nb of input bytes read so far */ |
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65 | |||
66 | Byte *next_out; /* next output byte should be put there */ |
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67 | uInt avail_out; /* remaining free space at next_out */ |
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68 | uLong total_out; /* total nb of bytes output so far */ |
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69 | |||
70 | char *msg; /* last error message, NULL if no error */ |
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71 | struct internal_state *state; /* not visible by applications */ |
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72 | |||
73 | void *workspace; /* memory allocated for this stream */ |
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74 | |||
75 | int data_type; /* best guess about the data type: ascii or binary */ |
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76 | uLong adler; /* adler32 value of the uncompressed data */ |
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77 | uLong reserved; /* reserved for future use */ |
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78 | } z_stream; |
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79 | |||
80 | typedef z_stream *z_streamp; |
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81 | |||
82 | /* |
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83 | The application must update next_in and avail_in when avail_in has |
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84 | dropped to zero. It must update next_out and avail_out when avail_out |
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85 | has dropped to zero. The application must initialize zalloc, zfree and |
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86 | opaque before calling the init function. All other fields are set by the |
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87 | compression library and must not be updated by the application. |
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88 | |||
89 | The opaque value provided by the application will be passed as the first |
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90 | parameter for calls of zalloc and zfree. This can be useful for custom |
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91 | memory management. The compression library attaches no meaning to the |
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92 | opaque value. |
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93 | |||
94 | zalloc must return NULL if there is not enough memory for the object. |
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95 | If zlib is used in a multi-threaded application, zalloc and zfree must be |
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96 | thread safe. |
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97 | |||
98 | On 16-bit systems, the functions zalloc and zfree must be able to allocate |
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99 | exactly 65536 bytes, but will not be required to allocate more than this |
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100 | if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, |
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101 | pointers returned by zalloc for objects of exactly 65536 bytes *must* |
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102 | have their offset normalized to zero. The default allocation function |
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103 | provided by this library ensures this (see zutil.c). To reduce memory |
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104 | requirements and avoid any allocation of 64K objects, at the expense of |
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105 | compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). |
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106 | |||
107 | The fields total_in and total_out can be used for statistics or |
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108 | progress reports. After compression, total_in holds the total size of |
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109 | the uncompressed data and may be saved for use in the decompressor |
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110 | (particularly if the decompressor wants to decompress everything in |
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111 | a single step). |
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112 | */ |
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113 | |||
114 | /* constants */ |
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115 | |||
116 | #define Z_NO_FLUSH 0 |
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117 | #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ |
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118 | #define Z_PACKET_FLUSH 2 |
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119 | #define Z_SYNC_FLUSH 3 |
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120 | #define Z_FULL_FLUSH 4 |
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121 | #define Z_FINISH 5 |
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122 | /* Allowed flush values; see deflate() below for details */ |
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123 | |||
124 | #define Z_OK 0 |
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125 | #define Z_STREAM_END 1 |
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126 | #define Z_NEED_DICT 2 |
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127 | #define Z_ERRNO (-1) |
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128 | #define Z_STREAM_ERROR (-2) |
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129 | #define Z_DATA_ERROR (-3) |
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130 | #define Z_MEM_ERROR (-4) |
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131 | #define Z_BUF_ERROR (-5) |
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132 | #define Z_VERSION_ERROR (-6) |
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133 | /* Return codes for the compression/decompression functions. Negative |
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134 | * values are errors, positive values are used for special but normal events. |
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135 | */ |
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136 | |||
137 | #define Z_NO_COMPRESSION 0 |
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138 | #define Z_BEST_SPEED 1 |
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139 | #define Z_BEST_COMPRESSION 9 |
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140 | #define Z_DEFAULT_COMPRESSION (-1) |
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141 | /* compression levels */ |
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142 | |||
143 | #define Z_FILTERED 1 |
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144 | #define Z_HUFFMAN_ONLY 2 |
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145 | #define Z_DEFAULT_STRATEGY 0 |
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146 | /* compression strategy; see deflateInit2() below for details */ |
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147 | |||
148 | #define Z_BINARY 0 |
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149 | #define Z_ASCII 1 |
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150 | #define Z_UNKNOWN 2 |
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151 | /* Possible values of the data_type field */ |
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152 | |||
153 | #define Z_DEFLATED 8 |
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154 | /* The deflate compression method (the only one supported in this version) */ |
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155 | |||
156 | /* basic functions */ |
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157 | |||
158 | extern const char * zlib_zlibVersion (void); |
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159 | /* The application can compare zlibVersion and ZLIB_VERSION for consistency. |
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160 | If the first character differs, the library code actually used is |
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161 | not compatible with the zlib.h header file used by the application. |
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162 | This check is automatically made by deflateInit and inflateInit. |
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163 | */ |
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164 | |||
165 | extern int zlib_deflate_workspacesize (void); |
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166 | /* |
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167 | Returns the number of bytes that needs to be allocated for a per- |
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168 | stream workspace. A pointer to this number of bytes should be |
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169 | returned in stream->workspace before calling zlib_deflateInit(). |
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170 | */ |
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171 | |||
172 | /* |
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173 | extern int deflateInit (z_streamp strm, int level); |
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174 | |||
175 | Initializes the internal stream state for compression. The fields |
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176 | zalloc, zfree and opaque must be initialized before by the caller. |
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177 | If zalloc and zfree are set to NULL, deflateInit updates them to |
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178 | use default allocation functions. |
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179 | |||
180 | The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: |
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181 | 1 gives best speed, 9 gives best compression, 0 gives no compression at |
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182 | all (the input data is simply copied a block at a time). |
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183 | Z_DEFAULT_COMPRESSION requests a default compromise between speed and |
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184 | compression (currently equivalent to level 6). |
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185 | |||
186 | deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not |
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187 | enough memory, Z_STREAM_ERROR if level is not a valid compression level, |
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188 | Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible |
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189 | with the version assumed by the caller (ZLIB_VERSION). |
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190 | msg is set to null if there is no error message. deflateInit does not |
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191 | perform any compression: this will be done by deflate(). |
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192 | */ |
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193 | |||
194 | |||
195 | extern int zlib_deflate (z_streamp strm, int flush); |
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196 | /* |
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197 | deflate compresses as much data as possible, and stops when the input |
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198 | buffer becomes empty or the output buffer becomes full. It may introduce some |
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199 | output latency (reading input without producing any output) except when |
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200 | forced to flush. |
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201 | |||
202 | The detailed semantics are as follows. deflate performs one or both of the |
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203 | following actions: |
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204 | |||
205 | - Compress more input starting at next_in and update next_in and avail_in |
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206 | accordingly. If not all input can be processed (because there is not |
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207 | enough room in the output buffer), next_in and avail_in are updated and |
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208 | processing will resume at this point for the next call of deflate(). |
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209 | |||
210 | - Provide more output starting at next_out and update next_out and avail_out |
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211 | accordingly. This action is forced if the parameter flush is non zero. |
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212 | Forcing flush frequently degrades the compression ratio, so this parameter |
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213 | should be set only when necessary (in interactive applications). |
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214 | Some output may be provided even if flush is not set. |
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215 | |||
216 | Before the call of deflate(), the application should ensure that at least |
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217 | one of the actions is possible, by providing more input and/or consuming |
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218 | more output, and updating avail_in or avail_out accordingly; avail_out |
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219 | should never be zero before the call. The application can consume the |
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220 | compressed output when it wants, for example when the output buffer is full |
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221 | (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK |
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222 | and with zero avail_out, it must be called again after making room in the |
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223 | output buffer because there might be more output pending. |
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224 | |||
225 | If the parameter flush is set to Z_SYNC_FLUSH, all pending output is |
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226 | flushed to the output buffer and the output is aligned on a byte boundary, so |
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227 | that the decompressor can get all input data available so far. (In particular |
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228 | avail_in is zero after the call if enough output space has been provided |
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229 | before the call.) Flushing may degrade compression for some compression |
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230 | algorithms and so it should be used only when necessary. |
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231 | |||
232 | If flush is set to Z_FULL_FLUSH, all output is flushed as with |
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233 | Z_SYNC_FLUSH, and the compression state is reset so that decompression can |
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234 | restart from this point if previous compressed data has been damaged or if |
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235 | random access is desired. Using Z_FULL_FLUSH too often can seriously degrade |
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236 | the compression. |
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237 | |||
238 | If deflate returns with avail_out == 0, this function must be called again |
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239 | with the same value of the flush parameter and more output space (updated |
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240 | avail_out), until the flush is complete (deflate returns with non-zero |
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241 | avail_out). |
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242 | |||
243 | If the parameter flush is set to Z_FINISH, pending input is processed, |
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244 | pending output is flushed and deflate returns with Z_STREAM_END if there |
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245 | was enough output space; if deflate returns with Z_OK, this function must be |
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246 | called again with Z_FINISH and more output space (updated avail_out) but no |
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247 | more input data, until it returns with Z_STREAM_END or an error. After |
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248 | deflate has returned Z_STREAM_END, the only possible operations on the |
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249 | stream are deflateReset or deflateEnd. |
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250 | |||
251 | Z_FINISH can be used immediately after deflateInit if all the compression |
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252 | is to be done in a single step. In this case, avail_out must be at least |
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253 | 0.1% larger than avail_in plus 12 bytes. If deflate does not return |
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254 | Z_STREAM_END, then it must be called again as described above. |
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255 | |||
256 | deflate() sets strm->adler to the adler32 checksum of all input read |
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257 | so far (that is, total_in bytes). |
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258 | |||
259 | deflate() may update data_type if it can make a good guess about |
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260 | the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered |
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261 | binary. This field is only for information purposes and does not affect |
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262 | the compression algorithm in any manner. |
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263 | |||
264 | deflate() returns Z_OK if some progress has been made (more input |
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265 | processed or more output produced), Z_STREAM_END if all input has been |
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266 | consumed and all output has been produced (only when flush is set to |
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267 | Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example |
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268 | if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible |
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269 | (for example avail_in or avail_out was zero). |
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270 | */ |
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271 | |||
272 | |||
273 | extern int zlib_deflateEnd (z_streamp strm); |
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274 | /* |
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275 | All dynamically allocated data structures for this stream are freed. |
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276 | This function discards any unprocessed input and does not flush any |
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277 | pending output. |
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278 | |||
279 | deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the |
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280 | stream state was inconsistent, Z_DATA_ERROR if the stream was freed |
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281 | prematurely (some input or output was discarded). In the error case, |
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282 | msg may be set but then points to a static string (which must not be |
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283 | deallocated). |
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284 | */ |
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285 | |||
286 | |||
287 | extern int zlib_inflate_workspacesize (void); |
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288 | /* |
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289 | Returns the number of bytes that needs to be allocated for a per- |
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290 | stream workspace. A pointer to this number of bytes should be |
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291 | returned in stream->workspace before calling zlib_inflateInit(). |
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292 | */ |
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293 | |||
294 | /* |
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295 | extern int zlib_inflateInit (z_streamp strm); |
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296 | |||
297 | Initializes the internal stream state for decompression. The fields |
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298 | next_in, avail_in, and workspace must be initialized before by |
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299 | the caller. If next_in is not NULL and avail_in is large enough (the exact |
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300 | value depends on the compression method), inflateInit determines the |
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301 | compression method from the zlib header and allocates all data structures |
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302 | accordingly; otherwise the allocation will be deferred to the first call of |
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303 | inflate. If zalloc and zfree are set to NULL, inflateInit updates them to |
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304 | use default allocation functions. |
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305 | |||
306 | inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough |
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307 | memory, Z_VERSION_ERROR if the zlib library version is incompatible with the |
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308 | version assumed by the caller. msg is set to null if there is no error |
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309 | message. inflateInit does not perform any decompression apart from reading |
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310 | the zlib header if present: this will be done by inflate(). (So next_in and |
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311 | avail_in may be modified, but next_out and avail_out are unchanged.) |
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312 | */ |
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313 | |||
314 | |||
315 | extern int zlib_inflate (z_streamp strm, int flush); |
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316 | /* |
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317 | inflate decompresses as much data as possible, and stops when the input |
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318 | buffer becomes empty or the output buffer becomes full. It may some |
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319 | introduce some output latency (reading input without producing any output) |
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320 | except when forced to flush. |
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321 | |||
322 | The detailed semantics are as follows. inflate performs one or both of the |
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323 | following actions: |
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324 | |||
325 | - Decompress more input starting at next_in and update next_in and avail_in |
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326 | accordingly. If not all input can be processed (because there is not |
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327 | enough room in the output buffer), next_in is updated and processing |
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328 | will resume at this point for the next call of inflate(). |
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329 | |||
330 | - Provide more output starting at next_out and update next_out and avail_out |
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331 | accordingly. inflate() provides as much output as possible, until there |
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332 | is no more input data or no more space in the output buffer (see below |
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333 | about the flush parameter). |
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334 | |||
335 | Before the call of inflate(), the application should ensure that at least |
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336 | one of the actions is possible, by providing more input and/or consuming |
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337 | more output, and updating the next_* and avail_* values accordingly. |
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338 | The application can consume the uncompressed output when it wants, for |
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339 | example when the output buffer is full (avail_out == 0), or after each |
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340 | call of inflate(). If inflate returns Z_OK and with zero avail_out, it |
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341 | must be called again after making room in the output buffer because there |
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342 | might be more output pending. |
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343 | |||
344 | If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much |
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345 | output as possible to the output buffer. The flushing behavior of inflate is |
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346 | not specified for values of the flush parameter other than Z_SYNC_FLUSH |
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347 | and Z_FINISH, but the current implementation actually flushes as much output |
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348 | as possible anyway. |
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349 | |||
350 | inflate() should normally be called until it returns Z_STREAM_END or an |
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351 | error. However if all decompression is to be performed in a single step |
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352 | (a single call of inflate), the parameter flush should be set to |
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353 | Z_FINISH. In this case all pending input is processed and all pending |
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354 | output is flushed; avail_out must be large enough to hold all the |
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355 | uncompressed data. (The size of the uncompressed data may have been saved |
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356 | by the compressor for this purpose.) The next operation on this stream must |
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357 | be inflateEnd to deallocate the decompression state. The use of Z_FINISH |
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358 | is never required, but can be used to inform inflate that a faster routine |
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359 | may be used for the single inflate() call. |
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360 | |||
361 | If a preset dictionary is needed at this point (see inflateSetDictionary |
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362 | below), inflate sets strm-adler to the adler32 checksum of the |
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363 | dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise |
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364 | it sets strm->adler to the adler32 checksum of all output produced |
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365 | so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or |
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366 | an error code as described below. At the end of the stream, inflate() |
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367 | checks that its computed adler32 checksum is equal to that saved by the |
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368 | compressor and returns Z_STREAM_END only if the checksum is correct. |
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369 | |||
370 | inflate() returns Z_OK if some progress has been made (more input processed |
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371 | or more output produced), Z_STREAM_END if the end of the compressed data has |
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372 | been reached and all uncompressed output has been produced, Z_NEED_DICT if a |
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373 | preset dictionary is needed at this point, Z_DATA_ERROR if the input data was |
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374 | corrupted (input stream not conforming to the zlib format or incorrect |
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375 | adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent |
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376 | (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not |
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377 | enough memory, Z_BUF_ERROR if no progress is possible or if there was not |
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378 | enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR |
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379 | case, the application may then call inflateSync to look for a good |
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380 | compression block. |
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381 | */ |
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382 | |||
383 | |||
384 | extern int zlib_inflateEnd (z_streamp strm); |
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385 | /* |
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386 | All dynamically allocated data structures for this stream are freed. |
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387 | This function discards any unprocessed input and does not flush any |
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388 | pending output. |
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389 | |||
390 | inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state |
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391 | was inconsistent. In the error case, msg may be set but then points to a |
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392 | static string (which must not be deallocated). |
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393 | */ |
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394 | |||
395 | /* Advanced functions */ |
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396 | |||
397 | /* |
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398 | The following functions are needed only in some special applications. |
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399 | */ |
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400 | |||
401 | /* |
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402 | extern int deflateInit2 (z_streamp strm, |
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403 | int level, |
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404 | int method, |
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405 | int windowBits, |
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406 | int memLevel, |
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407 | int strategy); |
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408 | |||
409 | This is another version of deflateInit with more compression options. The |
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410 | fields next_in, zalloc, zfree and opaque must be initialized before by |
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411 | the caller. |
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412 | |||
413 | The method parameter is the compression method. It must be Z_DEFLATED in |
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414 | this version of the library. |
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415 | |||
416 | The windowBits parameter is the base two logarithm of the window size |
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417 | (the size of the history buffer). It should be in the range 8..15 for this |
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418 | version of the library. Larger values of this parameter result in better |
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419 | compression at the expense of memory usage. The default value is 15 if |
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420 | deflateInit is used instead. |
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421 | |||
422 | The memLevel parameter specifies how much memory should be allocated |
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423 | for the internal compression state. memLevel=1 uses minimum memory but |
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424 | is slow and reduces compression ratio; memLevel=9 uses maximum memory |
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425 | for optimal speed. The default value is 8. See zconf.h for total memory |
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426 | usage as a function of windowBits and memLevel. |
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427 | |||
428 | The strategy parameter is used to tune the compression algorithm. Use the |
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429 | value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a |
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430 | filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no |
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431 | string match). Filtered data consists mostly of small values with a |
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432 | somewhat random distribution. In this case, the compression algorithm is |
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433 | tuned to compress them better. The effect of Z_FILTERED is to force more |
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434 | Huffman coding and less string matching; it is somewhat intermediate |
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435 | between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects |
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436 | the compression ratio but not the correctness of the compressed output even |
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437 | if it is not set appropriately. |
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438 | |||
439 | deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
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440 | memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid |
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441 | method). msg is set to null if there is no error message. deflateInit2 does |
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442 | not perform any compression: this will be done by deflate(). |
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443 | */ |
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444 | |||
445 | extern int zlib_deflateSetDictionary (z_streamp strm, |
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446 | const Byte *dictionary, |
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447 | uInt dictLength); |
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448 | /* |
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449 | Initializes the compression dictionary from the given byte sequence |
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450 | without producing any compressed output. This function must be called |
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451 | immediately after deflateInit, deflateInit2 or deflateReset, before any |
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452 | call of deflate. The compressor and decompressor must use exactly the same |
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453 | dictionary (see inflateSetDictionary). |
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454 | |||
455 | The dictionary should consist of strings (byte sequences) that are likely |
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456 | to be encountered later in the data to be compressed, with the most commonly |
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457 | used strings preferably put towards the end of the dictionary. Using a |
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458 | dictionary is most useful when the data to be compressed is short and can be |
||
459 | predicted with good accuracy; the data can then be compressed better than |
||
460 | with the default empty dictionary. |
||
461 | |||
462 | Depending on the size of the compression data structures selected by |
||
463 | deflateInit or deflateInit2, a part of the dictionary may in effect be |
||
464 | discarded, for example if the dictionary is larger than the window size in |
||
465 | deflate or deflate2. Thus the strings most likely to be useful should be |
||
466 | put at the end of the dictionary, not at the front. |
||
467 | |||
468 | Upon return of this function, strm->adler is set to the Adler32 value |
||
469 | of the dictionary; the decompressor may later use this value to determine |
||
470 | which dictionary has been used by the compressor. (The Adler32 value |
||
471 | applies to the whole dictionary even if only a subset of the dictionary is |
||
472 | actually used by the compressor.) |
||
473 | |||
474 | deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a |
||
475 | parameter is invalid (such as NULL dictionary) or the stream state is |
||
476 | inconsistent (for example if deflate has already been called for this stream |
||
477 | or if the compression method is bsort). deflateSetDictionary does not |
||
478 | perform any compression: this will be done by deflate(). |
||
479 | */ |
||
480 | |||
481 | extern int zlib_deflateCopy (z_streamp dest, 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 | extern int zlib_deflateReset (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 | extern int zlib_deflateParams (z_streamp strm, int level, int strategy); |
||
510 | /* |
||
511 | Dynamically update the compression level and compression strategy. The |
||
512 | interpretation of level and strategy is as in deflateInit2. This can be |
||
513 | used to switch between compression and straight copy of the input data, or |
||
514 | to switch to a different kind of input data requiring a different |
||
515 | strategy. If the compression level is changed, the input available so far |
||
516 | is compressed with the old level (and may be flushed); the new level will |
||
517 | take effect only at the next call of deflate(). |
||
518 | |||
519 | Before the call of deflateParams, the stream state must be set as for |
||
520 | a call of deflate(), since the currently available input may have to |
||
521 | be compressed and flushed. In particular, strm->avail_out must be non-zero. |
||
522 | |||
523 | deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source |
||
524 | stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR |
||
525 | if strm->avail_out was zero. |
||
526 | */ |
||
527 | |||
528 | /* |
||
529 | extern int inflateInit2 (z_streamp strm, int windowBits); |
||
530 | |||
531 | This is another version of inflateInit with an extra parameter. The |
||
532 | fields next_in, avail_in, zalloc, zfree and opaque must be initialized |
||
533 | before by the caller. |
||
534 | |||
535 | The windowBits parameter is the base two logarithm of the maximum window |
||
536 | size (the size of the history buffer). It should be in the range 8..15 for |
||
537 | this version of the library. The default value is 15 if inflateInit is used |
||
538 | instead. If a compressed stream with a larger window size is given as |
||
539 | input, inflate() will return with the error code Z_DATA_ERROR instead of |
||
540 | trying to allocate a larger window. |
||
541 | |||
542 | inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
||
543 | memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative |
||
544 | memLevel). msg is set to null if there is no error message. inflateInit2 |
||
545 | does not perform any decompression apart from reading the zlib header if |
||
546 | present: this will be done by inflate(). (So next_in and avail_in may be |
||
547 | modified, but next_out and avail_out are unchanged.) |
||
548 | */ |
||
549 | |||
550 | extern int zlib_inflateSetDictionary (z_streamp strm, |
||
551 | const Byte *dictionary, |
||
552 | uInt dictLength); |
||
553 | /* |
||
554 | Initializes the decompression dictionary from the given uncompressed byte |
||
555 | sequence. This function must be called immediately after a call of inflate |
||
556 | if this call returned Z_NEED_DICT. The dictionary chosen by the compressor |
||
557 | can be determined from the Adler32 value returned by this call of |
||
558 | inflate. The compressor and decompressor must use exactly the same |
||
559 | dictionary (see deflateSetDictionary). |
||
560 | |||
561 | inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a |
||
562 | parameter is invalid (such as NULL dictionary) or the stream state is |
||
563 | inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the |
||
564 | expected one (incorrect Adler32 value). inflateSetDictionary does not |
||
565 | perform any decompression: this will be done by subsequent calls of |
||
566 | inflate(). |
||
567 | */ |
||
568 | |||
569 | extern int zlib_inflateSync (z_streamp strm); |
||
570 | /* |
||
571 | Skips invalid compressed data until a full flush point (see above the |
||
572 | description of deflate with Z_FULL_FLUSH) can be found, or until all |
||
573 | available input is skipped. No output is provided. |
||
574 | |||
575 | inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR |
||
576 | if no more input was provided, Z_DATA_ERROR if no flush point has been found, |
||
577 | or Z_STREAM_ERROR if the stream structure was inconsistent. In the success |
||
578 | case, the application may save the current current value of total_in which |
||
579 | indicates where valid compressed data was found. In the error case, the |
||
580 | application may repeatedly call inflateSync, providing more input each time, |
||
581 | until success or end of the input data. |
||
582 | */ |
||
583 | |||
584 | extern int zlib_inflateReset (z_streamp strm); |
||
585 | /* |
||
586 | This function is equivalent to inflateEnd followed by inflateInit, |
||
587 | but does not free and reallocate all the internal decompression state. |
||
588 | The stream will keep attributes that may have been set by inflateInit2. |
||
589 | |||
590 | inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
||
591 | stream state was inconsistent (such as zalloc or state being NULL). |
||
592 | */ |
||
593 | |||
594 | extern int zlib_inflateIncomp (z_stream *strm); |
||
595 | /* |
||
596 | This function adds the data at next_in (avail_in bytes) to the output |
||
597 | history without performing any output. There must be no pending output, |
||
598 | and the decompressor must be expecting to see the start of a block. |
||
599 | Calling this function is equivalent to decompressing a stored block |
||
600 | containing the data at next_in (except that the data is not output). |
||
601 | */ |
||
602 | |||
603 | /* various hacks, don't look :) */ |
||
604 | |||
605 | /* deflateInit and inflateInit are macros to allow checking the zlib version |
||
606 | * and the compiler's view of z_stream: |
||
607 | */ |
||
608 | extern int zlib_deflateInit_ (z_streamp strm, int level, |
||
609 | const char *version, int stream_size); |
||
610 | extern int zlib_inflateInit_ (z_streamp strm, |
||
611 | const char *version, int stream_size); |
||
612 | extern int zlib_deflateInit2_ (z_streamp strm, int level, int method, |
||
613 | int windowBits, int memLevel, |
||
614 | int strategy, const char *version, |
||
615 | int stream_size); |
||
616 | extern int zlib_inflateInit2_ (z_streamp strm, int windowBits, |
||
617 | const char *version, int stream_size); |
||
618 | #define zlib_deflateInit(strm, level) \ |
||
619 | zlib_deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) |
||
620 | #define zlib_inflateInit(strm) \ |
||
621 | zlib_inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) |
||
622 | #define zlib_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ |
||
623 | zlib_deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ |
||
624 | (strategy), ZLIB_VERSION, sizeof(z_stream)) |
||
625 | #define zlib_inflateInit2(strm, windowBits) \ |
||
626 | zlib_inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) |
||
627 | |||
628 | |||
629 | #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL) |
||
630 | struct internal_state {int dummy;}; /* hack for buggy compilers */ |
||
631 | #endif |
||
632 | |||
633 | extern const char * zlib_zError (int err); |
||
634 | extern int zlib_inflateSyncPoint (z_streamp z); |
||
635 | extern const uLong * zlib_get_crc_table (void); |
||
636 | |||
637 | #endif /* _ZLIB_H */ |