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1896 | serge | 1 | /* zlib.h -- interface of the 'zlib' general purpose compression library |
2 | version 1.2.5, April 19th, 2010 |
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3 | |||
4 | Copyright (C) 1995-2010 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 http://www.ietf.org/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 "zconf.h" |
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35 | |||
36 | #ifdef __cplusplus |
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37 | extern "C" { |
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38 | #endif |
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39 | |||
40 | #define ZLIB_VERSION "1.2.5" |
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41 | #define ZLIB_VERNUM 0x1250 |
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42 | #define ZLIB_VER_MAJOR 1 |
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43 | #define ZLIB_VER_MINOR 2 |
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44 | #define ZLIB_VER_REVISION 5 |
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45 | #define ZLIB_VER_SUBREVISION 0 |
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46 | |||
47 | /* |
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48 | The 'zlib' compression library provides in-memory compression and |
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49 | decompression functions, including integrity checks of the uncompressed data. |
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50 | This version of the library supports only one compression method (deflation) |
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51 | but other algorithms will be added later and will have the same stream |
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52 | interface. |
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53 | |||
54 | Compression can be done in a single step if the buffers are large enough, |
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55 | or can be done by repeated calls of the compression function. In the latter |
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56 | case, the application must provide more input and/or consume the output |
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57 | (providing more output space) before each call. |
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58 | |||
59 | The compressed data format used by default by the in-memory functions is |
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60 | the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped |
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61 | around a deflate stream, which is itself documented in RFC 1951. |
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62 | |||
63 | The library also supports reading and writing files in gzip (.gz) format |
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64 | with an interface similar to that of stdio using the functions that start |
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65 | with "gz". The gzip format is different from the zlib format. gzip is a |
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66 | gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. |
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67 | |||
68 | This library can optionally read and write gzip streams in memory as well. |
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69 | |||
70 | The zlib format was designed to be compact and fast for use in memory |
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71 | and on communications channels. The gzip format was designed for single- |
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72 | file compression on file systems, has a larger header than zlib to maintain |
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73 | directory information, and uses a different, slower check method than zlib. |
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74 | |||
75 | The library does not install any signal handler. The decoder checks |
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76 | the consistency of the compressed data, so the library should never crash |
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77 | even in case of corrupted input. |
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78 | */ |
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79 | |||
80 | typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); |
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81 | typedef void (*free_func) OF((voidpf opaque, voidpf address)); |
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82 | |||
83 | struct internal_state; |
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84 | |||
85 | typedef struct z_stream_s { |
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86 | Bytef *next_in; /* next input byte */ |
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87 | uInt avail_in; /* number of bytes available at next_in */ |
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88 | uLong total_in; /* total nb of input bytes read so far */ |
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89 | |||
90 | Bytef *next_out; /* next output byte should be put there */ |
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91 | uInt avail_out; /* remaining free space at next_out */ |
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92 | uLong total_out; /* total nb of bytes output so far */ |
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93 | |||
94 | char *msg; /* last error message, NULL if no error */ |
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95 | struct internal_state FAR *state; /* not visible by applications */ |
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96 | |||
97 | alloc_func zalloc; /* used to allocate the internal state */ |
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98 | free_func zfree; /* used to free the internal state */ |
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99 | voidpf opaque; /* private data object passed to zalloc and zfree */ |
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100 | |||
101 | int data_type; /* best guess about the data type: binary or text */ |
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102 | uLong adler; /* adler32 value of the uncompressed data */ |
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103 | uLong reserved; /* reserved for future use */ |
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104 | } z_stream; |
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105 | |||
106 | typedef z_stream FAR *z_streamp; |
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107 | |||
108 | /* |
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109 | gzip header information passed to and from zlib routines. See RFC 1952 |
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110 | for more details on the meanings of these fields. |
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111 | */ |
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112 | typedef struct gz_header_s { |
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113 | int text; /* true if compressed data believed to be text */ |
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114 | uLong time; /* modification time */ |
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115 | int xflags; /* extra flags (not used when writing a gzip file) */ |
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116 | int os; /* operating system */ |
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117 | Bytef *extra; /* pointer to extra field or Z_NULL if none */ |
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118 | uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ |
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119 | uInt extra_max; /* space at extra (only when reading header) */ |
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120 | Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ |
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121 | uInt name_max; /* space at name (only when reading header) */ |
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122 | Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ |
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123 | uInt comm_max; /* space at comment (only when reading header) */ |
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124 | int hcrc; /* true if there was or will be a header crc */ |
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125 | int done; /* true when done reading gzip header (not used |
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126 | when writing a gzip file) */ |
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127 | } gz_header; |
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128 | |||
129 | typedef gz_header FAR *gz_headerp; |
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130 | |||
131 | /* |
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132 | The application must update next_in and avail_in when avail_in has dropped |
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133 | to zero. It must update next_out and avail_out when avail_out has dropped |
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134 | to zero. The application must initialize zalloc, zfree and opaque before |
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135 | calling the init function. All other fields are set by the compression |
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136 | library and must not be updated by the application. |
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137 | |||
138 | The opaque value provided by the application will be passed as the first |
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139 | parameter for calls of zalloc and zfree. This can be useful for custom |
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140 | memory management. The compression library attaches no meaning to the |
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141 | opaque value. |
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142 | |||
143 | zalloc must return Z_NULL if there is not enough memory for the object. |
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144 | If zlib is used in a multi-threaded application, zalloc and zfree must be |
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145 | thread safe. |
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146 | |||
147 | On 16-bit systems, the functions zalloc and zfree must be able to allocate |
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148 | exactly 65536 bytes, but will not be required to allocate more than this if |
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149 | the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers |
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150 | returned by zalloc for objects of exactly 65536 bytes *must* have their |
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151 | offset normalized to zero. The default allocation function provided by this |
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152 | library ensures this (see zutil.c). To reduce memory requirements and avoid |
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153 | any allocation of 64K objects, at the expense of compression ratio, compile |
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154 | the library with -DMAX_WBITS=14 (see zconf.h). |
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155 | |||
156 | The fields total_in and total_out can be used for statistics or progress |
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157 | reports. After compression, total_in holds the total size of the |
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158 | uncompressed data and may be saved for use in the decompressor (particularly |
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159 | if the decompressor wants to decompress everything in a single step). |
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160 | */ |
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161 | |||
162 | /* constants */ |
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163 | |||
164 | #define Z_NO_FLUSH 0 |
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165 | #define Z_PARTIAL_FLUSH 1 |
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166 | #define Z_SYNC_FLUSH 2 |
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167 | #define Z_FULL_FLUSH 3 |
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168 | #define Z_FINISH 4 |
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169 | #define Z_BLOCK 5 |
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170 | #define Z_TREES 6 |
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171 | /* Allowed flush values; see deflate() and inflate() below for details */ |
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172 | |||
173 | #define Z_OK 0 |
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174 | #define Z_STREAM_END 1 |
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175 | #define Z_NEED_DICT 2 |
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176 | #define Z_ERRNO (-1) |
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177 | #define Z_STREAM_ERROR (-2) |
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178 | #define Z_DATA_ERROR (-3) |
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179 | #define Z_MEM_ERROR (-4) |
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180 | #define Z_BUF_ERROR (-5) |
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181 | #define Z_VERSION_ERROR (-6) |
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182 | /* Return codes for the compression/decompression functions. Negative values |
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183 | * are errors, positive values are used for special but normal events. |
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184 | */ |
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185 | |||
186 | #define Z_NO_COMPRESSION 0 |
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187 | #define Z_BEST_SPEED 1 |
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188 | #define Z_BEST_COMPRESSION 9 |
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189 | #define Z_DEFAULT_COMPRESSION (-1) |
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190 | /* compression levels */ |
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191 | |||
192 | #define Z_FILTERED 1 |
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193 | #define Z_HUFFMAN_ONLY 2 |
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194 | #define Z_RLE 3 |
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195 | #define Z_FIXED 4 |
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196 | #define Z_DEFAULT_STRATEGY 0 |
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197 | /* compression strategy; see deflateInit2() below for details */ |
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198 | |||
199 | #define Z_BINARY 0 |
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200 | #define Z_TEXT 1 |
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201 | #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ |
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202 | #define Z_UNKNOWN 2 |
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203 | /* Possible values of the data_type field (though see inflate()) */ |
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204 | |||
205 | #define Z_DEFLATED 8 |
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206 | /* The deflate compression method (the only one supported in this version) */ |
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207 | |||
208 | #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ |
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209 | |||
210 | #define zlib_version zlibVersion() |
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211 | /* for compatibility with versions < 1.0.2 */ |
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212 | |||
213 | |||
214 | /* basic functions */ |
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215 | |||
216 | ZEXTERN const char * ZEXPORT zlibVersion OF((void)); |
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217 | /* The application can compare zlibVersion and ZLIB_VERSION for consistency. |
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218 | If the first character differs, the library code actually used is not |
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219 | compatible with the zlib.h header file used by the application. This check |
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220 | is automatically made by deflateInit and inflateInit. |
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221 | */ |
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222 | |||
223 | /* |
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224 | ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); |
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225 | |||
226 | Initializes the internal stream state for compression. The fields |
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227 | zalloc, zfree and opaque must be initialized before by the caller. If |
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228 | zalloc and zfree are set to Z_NULL, deflateInit updates them to use default |
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229 | allocation functions. |
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230 | |||
231 | The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: |
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232 | 1 gives best speed, 9 gives best compression, 0 gives no compression at all |
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233 | (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION |
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234 | requests a default compromise between speed and compression (currently |
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235 | equivalent to level 6). |
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236 | |||
237 | deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough |
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238 | memory, Z_STREAM_ERROR if level is not a valid compression level, or |
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239 | Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible |
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240 | with the version assumed by the caller (ZLIB_VERSION). msg is set to null |
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241 | if there is no error message. deflateInit does not perform any compression: |
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242 | this will be done by deflate(). |
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243 | */ |
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244 | |||
245 | |||
246 | ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); |
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247 | /* |
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248 | deflate compresses as much data as possible, and stops when the input |
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249 | buffer becomes empty or the output buffer becomes full. It may introduce |
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250 | some output latency (reading input without producing any output) except when |
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251 | forced to flush. |
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252 | |||
253 | The detailed semantics are as follows. deflate performs one or both of the |
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254 | following actions: |
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255 | |||
256 | - Compress more input starting at next_in and update next_in and avail_in |
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257 | accordingly. If not all input can be processed (because there is not |
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258 | enough room in the output buffer), next_in and avail_in are updated and |
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259 | processing will resume at this point for the next call of deflate(). |
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260 | |||
261 | - Provide more output starting at next_out and update next_out and avail_out |
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262 | accordingly. This action is forced if the parameter flush is non zero. |
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263 | Forcing flush frequently degrades the compression ratio, so this parameter |
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264 | should be set only when necessary (in interactive applications). Some |
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265 | output may be provided even if flush is not set. |
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266 | |||
267 | Before the call of deflate(), the application should ensure that at least |
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268 | one of the actions is possible, by providing more input and/or consuming more |
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269 | output, and updating avail_in or avail_out accordingly; avail_out should |
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270 | never be zero before the call. The application can consume the compressed |
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271 | output when it wants, for example when the output buffer is full (avail_out |
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272 | == 0), or after each call of deflate(). If deflate returns Z_OK and with |
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273 | zero avail_out, it must be called again after making room in the output |
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274 | buffer because there might be more output pending. |
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275 | |||
276 | Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to |
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277 | decide how much data to accumulate before producing output, in order to |
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278 | maximize compression. |
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279 | |||
280 | If the parameter flush is set to Z_SYNC_FLUSH, all pending output is |
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281 | flushed to the output buffer and the output is aligned on a byte boundary, so |
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282 | that the decompressor can get all input data available so far. (In |
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283 | particular avail_in is zero after the call if enough output space has been |
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284 | provided before the call.) Flushing may degrade compression for some |
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285 | compression algorithms and so it should be used only when necessary. This |
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286 | completes the current deflate block and follows it with an empty stored block |
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287 | that is three bits plus filler bits to the next byte, followed by four bytes |
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288 | (00 00 ff ff). |
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289 | |||
290 | If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the |
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291 | output buffer, but the output is not aligned to a byte boundary. All of the |
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292 | input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. |
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293 | This completes the current deflate block and follows it with an empty fixed |
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294 | codes block that is 10 bits long. This assures that enough bytes are output |
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295 | in order for the decompressor to finish the block before the empty fixed code |
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296 | block. |
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297 | |||
298 | If flush is set to Z_BLOCK, a deflate block is completed and emitted, as |
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299 | for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to |
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300 | seven bits of the current block are held to be written as the next byte after |
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301 | the next deflate block is completed. In this case, the decompressor may not |
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302 | be provided enough bits at this point in order to complete decompression of |
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303 | the data provided so far to the compressor. It may need to wait for the next |
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304 | block to be emitted. This is for advanced applications that need to control |
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305 | the emission of deflate blocks. |
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306 | |||
307 | If flush is set to Z_FULL_FLUSH, all output is flushed as with |
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308 | Z_SYNC_FLUSH, and the compression state is reset so that decompression can |
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309 | restart from this point if previous compressed data has been damaged or if |
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310 | random access is desired. Using Z_FULL_FLUSH too often can seriously degrade |
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311 | compression. |
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312 | |||
313 | If deflate returns with avail_out == 0, this function must be called again |
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314 | with the same value of the flush parameter and more output space (updated |
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315 | avail_out), until the flush is complete (deflate returns with non-zero |
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316 | avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that |
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317 | avail_out is greater than six to avoid repeated flush markers due to |
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318 | avail_out == 0 on return. |
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319 | |||
320 | If the parameter flush is set to Z_FINISH, pending input is processed, |
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321 | pending output is flushed and deflate returns with Z_STREAM_END if there was |
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322 | enough output space; if deflate returns with Z_OK, this function must be |
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323 | called again with Z_FINISH and more output space (updated avail_out) but no |
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324 | more input data, until it returns with Z_STREAM_END or an error. After |
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325 | deflate has returned Z_STREAM_END, the only possible operations on the stream |
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326 | are deflateReset or deflateEnd. |
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327 | |||
328 | Z_FINISH can be used immediately after deflateInit if all the compression |
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329 | is to be done in a single step. In this case, avail_out must be at least the |
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330 | value returned by deflateBound (see below). If deflate does not return |
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331 | Z_STREAM_END, then it must be called again as described above. |
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332 | |||
333 | deflate() sets strm->adler to the adler32 checksum of all input read |
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334 | so far (that is, total_in bytes). |
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335 | |||
336 | deflate() may update strm->data_type if it can make a good guess about |
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337 | the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered |
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338 | binary. This field is only for information purposes and does not affect the |
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339 | compression algorithm in any manner. |
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340 | |||
341 | deflate() returns Z_OK if some progress has been made (more input |
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342 | processed or more output produced), Z_STREAM_END if all input has been |
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343 | consumed and all output has been produced (only when flush is set to |
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344 | Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example |
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345 | if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible |
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346 | (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not |
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347 | fatal, and deflate() can be called again with more input and more output |
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348 | space to continue compressing. |
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349 | */ |
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350 | |||
351 | |||
352 | ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); |
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353 | /* |
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354 | All dynamically allocated data structures for this stream are freed. |
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355 | This function discards any unprocessed input and does not flush any pending |
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356 | output. |
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357 | |||
358 | deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the |
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359 | stream state was inconsistent, Z_DATA_ERROR if the stream was freed |
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360 | prematurely (some input or output was discarded). In the error case, msg |
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361 | may be set but then points to a static string (which must not be |
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362 | deallocated). |
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363 | */ |
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364 | |||
365 | |||
366 | /* |
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367 | ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); |
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368 | |||
369 | Initializes the internal stream state for decompression. The fields |
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370 | next_in, avail_in, zalloc, zfree and opaque must be initialized before by |
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371 | the caller. If next_in is not Z_NULL and avail_in is large enough (the |
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372 | exact value depends on the compression method), inflateInit determines the |
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373 | compression method from the zlib header and allocates all data structures |
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374 | accordingly; otherwise the allocation will be deferred to the first call of |
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375 | inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to |
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376 | use default allocation functions. |
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377 | |||
378 | inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough |
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379 | memory, Z_VERSION_ERROR if the zlib library version is incompatible with the |
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380 | version assumed by the caller, or Z_STREAM_ERROR if the parameters are |
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381 | invalid, such as a null pointer to the structure. msg is set to null if |
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382 | there is no error message. inflateInit does not perform any decompression |
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383 | apart from possibly reading the zlib header if present: actual decompression |
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384 | will be done by inflate(). (So next_in and avail_in may be modified, but |
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385 | next_out and avail_out are unused and unchanged.) The current implementation |
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386 | of inflateInit() does not process any header information -- that is deferred |
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387 | until inflate() is called. |
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388 | */ |
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389 | |||
390 | |||
391 | ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); |
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392 | /* |
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393 | inflate decompresses as much data as possible, and stops when the input |
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394 | buffer becomes empty or the output buffer becomes full. It may introduce |
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395 | some output latency (reading input without producing any output) except when |
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396 | forced to flush. |
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397 | |||
398 | The detailed semantics are as follows. inflate performs one or both of the |
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399 | following actions: |
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400 | |||
401 | - Decompress more input starting at next_in and update next_in and avail_in |
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402 | accordingly. If not all input can be processed (because there is not |
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403 | enough room in the output buffer), next_in is updated and processing will |
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404 | resume at this point for the next call of inflate(). |
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405 | |||
406 | - Provide more output starting at next_out and update next_out and avail_out |
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407 | accordingly. inflate() provides as much output as possible, until there is |
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408 | no more input data or no more space in the output buffer (see below about |
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409 | the flush parameter). |
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410 | |||
411 | Before the call of inflate(), the application should ensure that at least |
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412 | one of the actions is possible, by providing more input and/or consuming more |
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413 | output, and updating the next_* and avail_* values accordingly. The |
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414 | application can consume the uncompressed output when it wants, for example |
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415 | when the output buffer is full (avail_out == 0), or after each call of |
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416 | inflate(). If inflate returns Z_OK and with zero avail_out, it must be |
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417 | called again after making room in the output buffer because there might be |
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418 | more output pending. |
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419 | |||
420 | The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, |
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421 | Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much |
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422 | output as possible to the output buffer. Z_BLOCK requests that inflate() |
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423 | stop if and when it gets to the next deflate block boundary. When decoding |
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424 | the zlib or gzip format, this will cause inflate() to return immediately |
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425 | after the header and before the first block. When doing a raw inflate, |
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426 | inflate() will go ahead and process the first block, and will return when it |
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427 | gets to the end of that block, or when it runs out of data. |
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428 | |||
429 | The Z_BLOCK option assists in appending to or combining deflate streams. |
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430 | Also to assist in this, on return inflate() will set strm->data_type to the |
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431 | number of unused bits in the last byte taken from strm->next_in, plus 64 if |
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432 | inflate() is currently decoding the last block in the deflate stream, plus |
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433 | 128 if inflate() returned immediately after decoding an end-of-block code or |
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434 | decoding the complete header up to just before the first byte of the deflate |
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435 | stream. The end-of-block will not be indicated until all of the uncompressed |
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436 | data from that block has been written to strm->next_out. The number of |
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437 | unused bits may in general be greater than seven, except when bit 7 of |
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438 | data_type is set, in which case the number of unused bits will be less than |
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439 | eight. data_type is set as noted here every time inflate() returns for all |
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440 | flush options, and so can be used to determine the amount of currently |
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441 | consumed input in bits. |
||
442 | |||
443 | The Z_TREES option behaves as Z_BLOCK does, but it also returns when the |
||
444 | end of each deflate block header is reached, before any actual data in that |
||
445 | block is decoded. This allows the caller to determine the length of the |
||
446 | deflate block header for later use in random access within a deflate block. |
||
447 | 256 is added to the value of strm->data_type when inflate() returns |
||
448 | immediately after reaching the end of the deflate block header. |
||
449 | |||
450 | inflate() should normally be called until it returns Z_STREAM_END or an |
||
451 | error. However if all decompression is to be performed in a single step (a |
||
452 | single call of inflate), the parameter flush should be set to Z_FINISH. In |
||
453 | this case all pending input is processed and all pending output is flushed; |
||
454 | avail_out must be large enough to hold all the uncompressed data. (The size |
||
455 | of the uncompressed data may have been saved by the compressor for this |
||
456 | purpose.) The next operation on this stream must be inflateEnd to deallocate |
||
457 | the decompression state. The use of Z_FINISH is never required, but can be |
||
458 | used to inform inflate that a faster approach may be used for the single |
||
459 | inflate() call. |
||
460 | |||
461 | In this implementation, inflate() always flushes as much output as |
||
462 | possible to the output buffer, and always uses the faster approach on the |
||
463 | first call. So the only effect of the flush parameter in this implementation |
||
464 | is on the return value of inflate(), as noted below, or when it returns early |
||
465 | because Z_BLOCK or Z_TREES is used. |
||
466 | |||
467 | If a preset dictionary is needed after this call (see inflateSetDictionary |
||
468 | below), inflate sets strm->adler to the adler32 checksum of the dictionary |
||
469 | chosen by the compressor and returns Z_NEED_DICT; otherwise it sets |
||
470 | strm->adler to the adler32 checksum of all output produced so far (that is, |
||
471 | total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described |
||
472 | below. At the end of the stream, inflate() checks that its computed adler32 |
||
473 | checksum is equal to that saved by the compressor and returns Z_STREAM_END |
||
474 | only if the checksum is correct. |
||
475 | |||
476 | inflate() can decompress and check either zlib-wrapped or gzip-wrapped |
||
477 | deflate data. The header type is detected automatically, if requested when |
||
478 | initializing with inflateInit2(). Any information contained in the gzip |
||
479 | header is not retained, so applications that need that information should |
||
480 | instead use raw inflate, see inflateInit2() below, or inflateBack() and |
||
481 | perform their own processing of the gzip header and trailer. |
||
482 | |||
483 | inflate() returns Z_OK if some progress has been made (more input processed |
||
484 | or more output produced), Z_STREAM_END if the end of the compressed data has |
||
485 | been reached and all uncompressed output has been produced, Z_NEED_DICT if a |
||
486 | preset dictionary is needed at this point, Z_DATA_ERROR if the input data was |
||
487 | corrupted (input stream not conforming to the zlib format or incorrect check |
||
488 | value), Z_STREAM_ERROR if the stream structure was inconsistent (for example |
||
489 | next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory, |
||
490 | Z_BUF_ERROR if no progress is possible or if there was not enough room in the |
||
491 | output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and |
||
492 | inflate() can be called again with more input and more output space to |
||
493 | continue decompressing. If Z_DATA_ERROR is returned, the application may |
||
494 | then call inflateSync() to look for a good compression block if a partial |
||
495 | recovery of the data is desired. |
||
496 | */ |
||
497 | |||
498 | |||
499 | ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); |
||
500 | /* |
||
501 | All dynamically allocated data structures for this stream are freed. |
||
502 | This function discards any unprocessed input and does not flush any pending |
||
503 | output. |
||
504 | |||
505 | inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state |
||
506 | was inconsistent. In the error case, msg may be set but then points to a |
||
507 | static string (which must not be deallocated). |
||
508 | */ |
||
509 | |||
510 | |||
511 | /* Advanced functions */ |
||
512 | |||
513 | /* |
||
514 | The following functions are needed only in some special applications. |
||
515 | */ |
||
516 | |||
517 | /* |
||
518 | ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, |
||
519 | int level, |
||
520 | int method, |
||
521 | int windowBits, |
||
522 | int memLevel, |
||
523 | int strategy)); |
||
524 | |||
525 | This is another version of deflateInit with more compression options. The |
||
526 | fields next_in, zalloc, zfree and opaque must be initialized before by the |
||
527 | caller. |
||
528 | |||
529 | The method parameter is the compression method. It must be Z_DEFLATED in |
||
530 | this version of the library. |
||
531 | |||
532 | The windowBits parameter is the base two logarithm of the window size |
||
533 | (the size of the history buffer). It should be in the range 8..15 for this |
||
534 | version of the library. Larger values of this parameter result in better |
||
535 | compression at the expense of memory usage. The default value is 15 if |
||
536 | deflateInit is used instead. |
||
537 | |||
538 | windowBits can also be -8..-15 for raw deflate. In this case, -windowBits |
||
539 | determines the window size. deflate() will then generate raw deflate data |
||
540 | with no zlib header or trailer, and will not compute an adler32 check value. |
||
541 | |||
542 | windowBits can also be greater than 15 for optional gzip encoding. Add |
||
543 | 16 to windowBits to write a simple gzip header and trailer around the |
||
544 | compressed data instead of a zlib wrapper. The gzip header will have no |
||
545 | file name, no extra data, no comment, no modification time (set to zero), no |
||
546 | header crc, and the operating system will be set to 255 (unknown). If a |
||
547 | gzip stream is being written, strm->adler is a crc32 instead of an adler32. |
||
548 | |||
549 | The memLevel parameter specifies how much memory should be allocated |
||
550 | for the internal compression state. memLevel=1 uses minimum memory but is |
||
551 | slow and reduces compression ratio; memLevel=9 uses maximum memory for |
||
552 | optimal speed. The default value is 8. See zconf.h for total memory usage |
||
553 | as a function of windowBits and memLevel. |
||
554 | |||
555 | The strategy parameter is used to tune the compression algorithm. Use the |
||
556 | value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a |
||
557 | filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no |
||
558 | string match), or Z_RLE to limit match distances to one (run-length |
||
559 | encoding). Filtered data consists mostly of small values with a somewhat |
||
560 | random distribution. In this case, the compression algorithm is tuned to |
||
561 | compress them better. The effect of Z_FILTERED is to force more Huffman |
||
562 | coding and less string matching; it is somewhat intermediate between |
||
563 | Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as |
||
564 | fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The |
||
565 | strategy parameter only affects the compression ratio but not the |
||
566 | correctness of the compressed output even if it is not set appropriately. |
||
567 | Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler |
||
568 | decoder for special applications. |
||
569 | |||
570 | deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
||
571 | memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid |
||
572 | method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is |
||
573 | incompatible with the version assumed by the caller (ZLIB_VERSION). msg is |
||
574 | set to null if there is no error message. deflateInit2 does not perform any |
||
575 | compression: this will be done by deflate(). |
||
576 | */ |
||
577 | |||
578 | ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, |
||
579 | const Bytef *dictionary, |
||
580 | uInt dictLength)); |
||
581 | /* |
||
582 | Initializes the compression dictionary from the given byte sequence |
||
583 | without producing any compressed output. This function must be called |
||
584 | immediately after deflateInit, deflateInit2 or deflateReset, before any call |
||
585 | of deflate. The compressor and decompressor must use exactly the same |
||
586 | dictionary (see inflateSetDictionary). |
||
587 | |||
588 | The dictionary should consist of strings (byte sequences) that are likely |
||
589 | to be encountered later in the data to be compressed, with the most commonly |
||
590 | used strings preferably put towards the end of the dictionary. Using a |
||
591 | dictionary is most useful when the data to be compressed is short and can be |
||
592 | predicted with good accuracy; the data can then be compressed better than |
||
593 | with the default empty dictionary. |
||
594 | |||
595 | Depending on the size of the compression data structures selected by |
||
596 | deflateInit or deflateInit2, a part of the dictionary may in effect be |
||
597 | discarded, for example if the dictionary is larger than the window size |
||
598 | provided in deflateInit or deflateInit2. Thus the strings most likely to be |
||
599 | useful should be put at the end of the dictionary, not at the front. In |
||
600 | addition, the current implementation of deflate will use at most the window |
||
601 | size minus 262 bytes of the provided dictionary. |
||
602 | |||
603 | Upon return of this function, strm->adler is set to the adler32 value |
||
604 | of the dictionary; the decompressor may later use this value to determine |
||
605 | which dictionary has been used by the compressor. (The adler32 value |
||
606 | applies to the whole dictionary even if only a subset of the dictionary is |
||
607 | actually used by the compressor.) If a raw deflate was requested, then the |
||
608 | adler32 value is not computed and strm->adler is not set. |
||
609 | |||
610 | deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a |
||
611 | parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is |
||
612 | inconsistent (for example if deflate has already been called for this stream |
||
613 | or if the compression method is bsort). deflateSetDictionary does not |
||
614 | perform any compression: this will be done by deflate(). |
||
615 | */ |
||
616 | |||
617 | ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, |
||
618 | z_streamp source)); |
||
619 | /* |
||
620 | Sets the destination stream as a complete copy of the source stream. |
||
621 | |||
622 | This function can be useful when several compression strategies will be |
||
623 | tried, for example when there are several ways of pre-processing the input |
||
624 | data with a filter. The streams that will be discarded should then be freed |
||
625 | by calling deflateEnd. Note that deflateCopy duplicates the internal |
||
626 | compression state which can be quite large, so this strategy is slow and can |
||
627 | consume lots of memory. |
||
628 | |||
629 | deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
||
630 | enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
||
631 | (such as zalloc being Z_NULL). msg is left unchanged in both source and |
||
632 | destination. |
||
633 | */ |
||
634 | |||
635 | ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); |
||
636 | /* |
||
637 | This function is equivalent to deflateEnd followed by deflateInit, |
||
638 | but does not free and reallocate all the internal compression state. The |
||
639 | stream will keep the same compression level and any other attributes that |
||
640 | may have been set by deflateInit2. |
||
641 | |||
642 | deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
||
643 | stream state was inconsistent (such as zalloc or state being Z_NULL). |
||
644 | */ |
||
645 | |||
646 | ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, |
||
647 | int level, |
||
648 | int strategy)); |
||
649 | /* |
||
650 | Dynamically update the compression level and compression strategy. The |
||
651 | interpretation of level and strategy is as in deflateInit2. This can be |
||
652 | used to switch between compression and straight copy of the input data, or |
||
653 | to switch to a different kind of input data requiring a different strategy. |
||
654 | If the compression level is changed, the input available so far is |
||
655 | compressed with the old level (and may be flushed); the new level will take |
||
656 | effect only at the next call of deflate(). |
||
657 | |||
658 | Before the call of deflateParams, the stream state must be set as for |
||
659 | a call of deflate(), since the currently available input may have to be |
||
660 | compressed and flushed. In particular, strm->avail_out must be non-zero. |
||
661 | |||
662 | deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source |
||
663 | stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if |
||
664 | strm->avail_out was zero. |
||
665 | */ |
||
666 | |||
667 | ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, |
||
668 | int good_length, |
||
669 | int max_lazy, |
||
670 | int nice_length, |
||
671 | int max_chain)); |
||
672 | /* |
||
673 | Fine tune deflate's internal compression parameters. This should only be |
||
674 | used by someone who understands the algorithm used by zlib's deflate for |
||
675 | searching for the best matching string, and even then only by the most |
||
676 | fanatic optimizer trying to squeeze out the last compressed bit for their |
||
677 | specific input data. Read the deflate.c source code for the meaning of the |
||
678 | max_lazy, good_length, nice_length, and max_chain parameters. |
||
679 | |||
680 | deflateTune() can be called after deflateInit() or deflateInit2(), and |
||
681 | returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. |
||
682 | */ |
||
683 | |||
684 | ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, |
||
685 | uLong sourceLen)); |
||
686 | /* |
||
687 | deflateBound() returns an upper bound on the compressed size after |
||
688 | deflation of sourceLen bytes. It must be called after deflateInit() or |
||
689 | deflateInit2(), and after deflateSetHeader(), if used. This would be used |
||
690 | to allocate an output buffer for deflation in a single pass, and so would be |
||
691 | called before deflate(). |
||
692 | */ |
||
693 | |||
694 | ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, |
||
695 | int bits, |
||
696 | int value)); |
||
697 | /* |
||
698 | deflatePrime() inserts bits in the deflate output stream. The intent |
||
699 | is that this function is used to start off the deflate output with the bits |
||
700 | leftover from a previous deflate stream when appending to it. As such, this |
||
701 | function can only be used for raw deflate, and must be used before the first |
||
702 | deflate() call after a deflateInit2() or deflateReset(). bits must be less |
||
703 | than or equal to 16, and that many of the least significant bits of value |
||
704 | will be inserted in the output. |
||
705 | |||
706 | deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source |
||
707 | stream state was inconsistent. |
||
708 | */ |
||
709 | |||
710 | ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, |
||
711 | gz_headerp head)); |
||
712 | /* |
||
713 | deflateSetHeader() provides gzip header information for when a gzip |
||
714 | stream is requested by deflateInit2(). deflateSetHeader() may be called |
||
715 | after deflateInit2() or deflateReset() and before the first call of |
||
716 | deflate(). The text, time, os, extra field, name, and comment information |
||
717 | in the provided gz_header structure are written to the gzip header (xflag is |
||
718 | ignored -- the extra flags are set according to the compression level). The |
||
719 | caller must assure that, if not Z_NULL, name and comment are terminated with |
||
720 | a zero byte, and that if extra is not Z_NULL, that extra_len bytes are |
||
721 | available there. If hcrc is true, a gzip header crc is included. Note that |
||
722 | the current versions of the command-line version of gzip (up through version |
||
723 | 1.3.x) do not support header crc's, and will report that it is a "multi-part |
||
724 | gzip file" and give up. |
||
725 | |||
726 | If deflateSetHeader is not used, the default gzip header has text false, |
||
727 | the time set to zero, and os set to 255, with no extra, name, or comment |
||
728 | fields. The gzip header is returned to the default state by deflateReset(). |
||
729 | |||
730 | deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source |
||
731 | stream state was inconsistent. |
||
732 | */ |
||
733 | |||
734 | /* |
||
735 | ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, |
||
736 | int windowBits)); |
||
737 | |||
738 | This is another version of inflateInit with an extra parameter. The |
||
739 | fields next_in, avail_in, zalloc, zfree and opaque must be initialized |
||
740 | before by the caller. |
||
741 | |||
742 | The windowBits parameter is the base two logarithm of the maximum window |
||
743 | size (the size of the history buffer). It should be in the range 8..15 for |
||
744 | this version of the library. The default value is 15 if inflateInit is used |
||
745 | instead. windowBits must be greater than or equal to the windowBits value |
||
746 | provided to deflateInit2() while compressing, or it must be equal to 15 if |
||
747 | deflateInit2() was not used. If a compressed stream with a larger window |
||
748 | size is given as input, inflate() will return with the error code |
||
749 | Z_DATA_ERROR instead of trying to allocate a larger window. |
||
750 | |||
751 | windowBits can also be zero to request that inflate use the window size in |
||
752 | the zlib header of the compressed stream. |
||
753 | |||
754 | windowBits can also be -8..-15 for raw inflate. In this case, -windowBits |
||
755 | determines the window size. inflate() will then process raw deflate data, |
||
756 | not looking for a zlib or gzip header, not generating a check value, and not |
||
757 | looking for any check values for comparison at the end of the stream. This |
||
758 | is for use with other formats that use the deflate compressed data format |
||
759 | such as zip. Those formats provide their own check values. If a custom |
||
760 | format is developed using the raw deflate format for compressed data, it is |
||
761 | recommended that a check value such as an adler32 or a crc32 be applied to |
||
762 | the uncompressed data as is done in the zlib, gzip, and zip formats. For |
||
763 | most applications, the zlib format should be used as is. Note that comments |
||
764 | above on the use in deflateInit2() applies to the magnitude of windowBits. |
||
765 | |||
766 | windowBits can also be greater than 15 for optional gzip decoding. Add |
||
767 | 32 to windowBits to enable zlib and gzip decoding with automatic header |
||
768 | detection, or add 16 to decode only the gzip format (the zlib format will |
||
769 | return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a |
||
770 | crc32 instead of an adler32. |
||
771 | |||
772 | inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
||
773 | memory, Z_VERSION_ERROR if the zlib library version is incompatible with the |
||
774 | version assumed by the caller, or Z_STREAM_ERROR if the parameters are |
||
775 | invalid, such as a null pointer to the structure. msg is set to null if |
||
776 | there is no error message. inflateInit2 does not perform any decompression |
||
777 | apart from possibly reading the zlib header if present: actual decompression |
||
778 | will be done by inflate(). (So next_in and avail_in may be modified, but |
||
779 | next_out and avail_out are unused and unchanged.) The current implementation |
||
780 | of inflateInit2() does not process any header information -- that is |
||
781 | deferred until inflate() is called. |
||
782 | */ |
||
783 | |||
784 | ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, |
||
785 | const Bytef *dictionary, |
||
786 | uInt dictLength)); |
||
787 | /* |
||
788 | Initializes the decompression dictionary from the given uncompressed byte |
||
789 | sequence. This function must be called immediately after a call of inflate, |
||
790 | if that call returned Z_NEED_DICT. The dictionary chosen by the compressor |
||
791 | can be determined from the adler32 value returned by that call of inflate. |
||
792 | The compressor and decompressor must use exactly the same dictionary (see |
||
793 | deflateSetDictionary). For raw inflate, this function can be called |
||
794 | immediately after inflateInit2() or inflateReset() and before any call of |
||
795 | inflate() to set the dictionary. The application must insure that the |
||
796 | dictionary that was used for compression is provided. |
||
797 | |||
798 | inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a |
||
799 | parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is |
||
800 | inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the |
||
801 | expected one (incorrect adler32 value). inflateSetDictionary does not |
||
802 | perform any decompression: this will be done by subsequent calls of |
||
803 | inflate(). |
||
804 | */ |
||
805 | |||
806 | ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); |
||
807 | /* |
||
808 | Skips invalid compressed data until a full flush point (see above the |
||
809 | description of deflate with Z_FULL_FLUSH) can be found, or until all |
||
810 | available input is skipped. No output is provided. |
||
811 | |||
812 | inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR |
||
813 | if no more input was provided, Z_DATA_ERROR if no flush point has been |
||
814 | found, or Z_STREAM_ERROR if the stream structure was inconsistent. In the |
||
815 | success case, the application may save the current current value of total_in |
||
816 | which indicates where valid compressed data was found. In the error case, |
||
817 | the application may repeatedly call inflateSync, providing more input each |
||
818 | time, until success or end of the input data. |
||
819 | */ |
||
820 | |||
821 | ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, |
||
822 | z_streamp source)); |
||
823 | /* |
||
824 | Sets the destination stream as a complete copy of the source stream. |
||
825 | |||
826 | This function can be useful when randomly accessing a large stream. The |
||
827 | first pass through the stream can periodically record the inflate state, |
||
828 | allowing restarting inflate at those points when randomly accessing the |
||
829 | stream. |
||
830 | |||
831 | inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
||
832 | enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
||
833 | (such as zalloc being Z_NULL). msg is left unchanged in both source and |
||
834 | destination. |
||
835 | */ |
||
836 | |||
837 | ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); |
||
838 | /* |
||
839 | This function is equivalent to inflateEnd followed by inflateInit, |
||
840 | but does not free and reallocate all the internal decompression state. The |
||
841 | stream will keep attributes that may have been set by inflateInit2. |
||
842 | |||
843 | inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
||
844 | stream state was inconsistent (such as zalloc or state being Z_NULL). |
||
845 | */ |
||
846 | |||
847 | ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm, |
||
848 | int windowBits)); |
||
849 | /* |
||
850 | This function is the same as inflateReset, but it also permits changing |
||
851 | the wrap and window size requests. The windowBits parameter is interpreted |
||
852 | the same as it is for inflateInit2. |
||
853 | |||
854 | inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source |
||
855 | stream state was inconsistent (such as zalloc or state being Z_NULL), or if |
||
856 | the windowBits parameter is invalid. |
||
857 | */ |
||
858 | |||
859 | ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, |
||
860 | int bits, |
||
861 | int value)); |
||
862 | /* |
||
863 | This function inserts bits in the inflate input stream. The intent is |
||
864 | that this function is used to start inflating at a bit position in the |
||
865 | middle of a byte. The provided bits will be used before any bytes are used |
||
866 | from next_in. This function should only be used with raw inflate, and |
||
867 | should be used before the first inflate() call after inflateInit2() or |
||
868 | inflateReset(). bits must be less than or equal to 16, and that many of the |
||
869 | least significant bits of value will be inserted in the input. |
||
870 | |||
871 | If bits is negative, then the input stream bit buffer is emptied. Then |
||
872 | inflatePrime() can be called again to put bits in the buffer. This is used |
||
873 | to clear out bits leftover after feeding inflate a block description prior |
||
874 | to feeding inflate codes. |
||
875 | |||
876 | inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source |
||
877 | stream state was inconsistent. |
||
878 | */ |
||
879 | |||
880 | ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); |
||
881 | /* |
||
882 | This function returns two values, one in the lower 16 bits of the return |
||
883 | value, and the other in the remaining upper bits, obtained by shifting the |
||
884 | return value down 16 bits. If the upper value is -1 and the lower value is |
||
885 | zero, then inflate() is currently decoding information outside of a block. |
||
886 | If the upper value is -1 and the lower value is non-zero, then inflate is in |
||
887 | the middle of a stored block, with the lower value equaling the number of |
||
888 | bytes from the input remaining to copy. If the upper value is not -1, then |
||
889 | it is the number of bits back from the current bit position in the input of |
||
890 | the code (literal or length/distance pair) currently being processed. In |
||
891 | that case the lower value is the number of bytes already emitted for that |
||
892 | code. |
||
893 | |||
894 | A code is being processed if inflate is waiting for more input to complete |
||
895 | decoding of the code, or if it has completed decoding but is waiting for |
||
896 | more output space to write the literal or match data. |
||
897 | |||
898 | inflateMark() is used to mark locations in the input data for random |
||
899 | access, which may be at bit positions, and to note those cases where the |
||
900 | output of a code may span boundaries of random access blocks. The current |
||
901 | location in the input stream can be determined from avail_in and data_type |
||
902 | as noted in the description for the Z_BLOCK flush parameter for inflate. |
||
903 | |||
904 | inflateMark returns the value noted above or -1 << 16 if the provided |
||
905 | source stream state was inconsistent. |
||
906 | */ |
||
907 | |||
908 | ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, |
||
909 | gz_headerp head)); |
||
910 | /* |
||
911 | inflateGetHeader() requests that gzip header information be stored in the |
||
912 | provided gz_header structure. inflateGetHeader() may be called after |
||
913 | inflateInit2() or inflateReset(), and before the first call of inflate(). |
||
914 | As inflate() processes the gzip stream, head->done is zero until the header |
||
915 | is completed, at which time head->done is set to one. If a zlib stream is |
||
916 | being decoded, then head->done is set to -1 to indicate that there will be |
||
917 | no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be |
||
918 | used to force inflate() to return immediately after header processing is |
||
919 | complete and before any actual data is decompressed. |
||
920 | |||
921 | The text, time, xflags, and os fields are filled in with the gzip header |
||
922 | contents. hcrc is set to true if there is a header CRC. (The header CRC |
||
923 | was valid if done is set to one.) If extra is not Z_NULL, then extra_max |
||
924 | contains the maximum number of bytes to write to extra. Once done is true, |
||
925 | extra_len contains the actual extra field length, and extra contains the |
||
926 | extra field, or that field truncated if extra_max is less than extra_len. |
||
927 | If name is not Z_NULL, then up to name_max characters are written there, |
||
928 | terminated with a zero unless the length is greater than name_max. If |
||
929 | comment is not Z_NULL, then up to comm_max characters are written there, |
||
930 | terminated with a zero unless the length is greater than comm_max. When any |
||
931 | of extra, name, or comment are not Z_NULL and the respective field is not |
||
932 | present in the header, then that field is set to Z_NULL to signal its |
||
933 | absence. This allows the use of deflateSetHeader() with the returned |
||
934 | structure to duplicate the header. However if those fields are set to |
||
935 | allocated memory, then the application will need to save those pointers |
||
936 | elsewhere so that they can be eventually freed. |
||
937 | |||
938 | If inflateGetHeader is not used, then the header information is simply |
||
939 | discarded. The header is always checked for validity, including the header |
||
940 | CRC if present. inflateReset() will reset the process to discard the header |
||
941 | information. The application would need to call inflateGetHeader() again to |
||
942 | retrieve the header from the next gzip stream. |
||
943 | |||
944 | inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source |
||
945 | stream state was inconsistent. |
||
946 | */ |
||
947 | |||
948 | /* |
||
949 | ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, |
||
950 | unsigned char FAR *window)); |
||
951 | |||
952 | Initialize the internal stream state for decompression using inflateBack() |
||
953 | calls. The fields zalloc, zfree and opaque in strm must be initialized |
||
954 | before the call. If zalloc and zfree are Z_NULL, then the default library- |
||
955 | derived memory allocation routines are used. windowBits is the base two |
||
956 | logarithm of the window size, in the range 8..15. window is a caller |
||
957 | supplied buffer of that size. Except for special applications where it is |
||
958 | assured that deflate was used with small window sizes, windowBits must be 15 |
||
959 | and a 32K byte window must be supplied to be able to decompress general |
||
960 | deflate streams. |
||
961 | |||
962 | See inflateBack() for the usage of these routines. |
||
963 | |||
964 | inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of |
||
965 | the paramaters are invalid, Z_MEM_ERROR if the internal state could not be |
||
966 | allocated, or Z_VERSION_ERROR if the version of the library does not match |
||
967 | the version of the header file. |
||
968 | */ |
||
969 | |||
970 | typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *)); |
||
971 | typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); |
||
972 | |||
973 | ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, |
||
974 | in_func in, void FAR *in_desc, |
||
975 | out_func out, void FAR *out_desc)); |
||
976 | /* |
||
977 | inflateBack() does a raw inflate with a single call using a call-back |
||
978 | interface for input and output. This is more efficient than inflate() for |
||
979 | file i/o applications in that it avoids copying between the output and the |
||
980 | sliding window by simply making the window itself the output buffer. This |
||
981 | function trusts the application to not change the output buffer passed by |
||
982 | the output function, at least until inflateBack() returns. |
||
983 | |||
984 | inflateBackInit() must be called first to allocate the internal state |
||
985 | and to initialize the state with the user-provided window buffer. |
||
986 | inflateBack() may then be used multiple times to inflate a complete, raw |
||
987 | deflate stream with each call. inflateBackEnd() is then called to free the |
||
988 | allocated state. |
||
989 | |||
990 | A raw deflate stream is one with no zlib or gzip header or trailer. |
||
991 | This routine would normally be used in a utility that reads zip or gzip |
||
992 | files and writes out uncompressed files. The utility would decode the |
||
993 | header and process the trailer on its own, hence this routine expects only |
||
994 | the raw deflate stream to decompress. This is different from the normal |
||
995 | behavior of inflate(), which expects either a zlib or gzip header and |
||
996 | trailer around the deflate stream. |
||
997 | |||
998 | inflateBack() uses two subroutines supplied by the caller that are then |
||
999 | called by inflateBack() for input and output. inflateBack() calls those |
||
1000 | routines until it reads a complete deflate stream and writes out all of the |
||
1001 | uncompressed data, or until it encounters an error. The function's |
||
1002 | parameters and return types are defined above in the in_func and out_func |
||
1003 | typedefs. inflateBack() will call in(in_desc, &buf) which should return the |
||
1004 | number of bytes of provided input, and a pointer to that input in buf. If |
||
1005 | there is no input available, in() must return zero--buf is ignored in that |
||
1006 | case--and inflateBack() will return a buffer error. inflateBack() will call |
||
1007 | out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() |
||
1008 | should return zero on success, or non-zero on failure. If out() returns |
||
1009 | non-zero, inflateBack() will return with an error. Neither in() nor out() |
||
1010 | are permitted to change the contents of the window provided to |
||
1011 | inflateBackInit(), which is also the buffer that out() uses to write from. |
||
1012 | The length written by out() will be at most the window size. Any non-zero |
||
1013 | amount of input may be provided by in(). |
||
1014 | |||
1015 | For convenience, inflateBack() can be provided input on the first call by |
||
1016 | setting strm->next_in and strm->avail_in. If that input is exhausted, then |
||
1017 | in() will be called. Therefore strm->next_in must be initialized before |
||
1018 | calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called |
||
1019 | immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in |
||
1020 | must also be initialized, and then if strm->avail_in is not zero, input will |
||
1021 | initially be taken from strm->next_in[0 .. strm->avail_in - 1]. |
||
1022 | |||
1023 | The in_desc and out_desc parameters of inflateBack() is passed as the |
||
1024 | first parameter of in() and out() respectively when they are called. These |
||
1025 | descriptors can be optionally used to pass any information that the caller- |
||
1026 | supplied in() and out() functions need to do their job. |
||
1027 | |||
1028 | On return, inflateBack() will set strm->next_in and strm->avail_in to |
||
1029 | pass back any unused input that was provided by the last in() call. The |
||
1030 | return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR |
||
1031 | if in() or out() returned an error, Z_DATA_ERROR if there was a format error |
||
1032 | in the deflate stream (in which case strm->msg is set to indicate the nature |
||
1033 | of the error), or Z_STREAM_ERROR if the stream was not properly initialized. |
||
1034 | In the case of Z_BUF_ERROR, an input or output error can be distinguished |
||
1035 | using strm->next_in which will be Z_NULL only if in() returned an error. If |
||
1036 | strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning |
||
1037 | non-zero. (in() will always be called before out(), so strm->next_in is |
||
1038 | assured to be defined if out() returns non-zero.) Note that inflateBack() |
||
1039 | cannot return Z_OK. |
||
1040 | */ |
||
1041 | |||
1042 | ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); |
||
1043 | /* |
||
1044 | All memory allocated by inflateBackInit() is freed. |
||
1045 | |||
1046 | inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream |
||
1047 | state was inconsistent. |
||
1048 | */ |
||
1049 | |||
1050 | ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); |
||
1051 | /* Return flags indicating compile-time options. |
||
1052 | |||
1053 | Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: |
||
1054 | 1.0: size of uInt |
||
1055 | 3.2: size of uLong |
||
1056 | 5.4: size of voidpf (pointer) |
||
1057 | 7.6: size of z_off_t |
||
1058 | |||
1059 | Compiler, assembler, and debug options: |
||
1060 | 8: DEBUG |
||
1061 | 9: ASMV or ASMINF -- use ASM code |
||
1062 | 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention |
||
1063 | 11: 0 (reserved) |
||
1064 | |||
1065 | One-time table building (smaller code, but not thread-safe if true): |
||
1066 | 12: BUILDFIXED -- build static block decoding tables when needed |
||
1067 | 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed |
||
1068 | 14,15: 0 (reserved) |
||
1069 | |||
1070 | Library content (indicates missing functionality): |
||
1071 | 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking |
||
1072 | deflate code when not needed) |
||
1073 | 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect |
||
1074 | and decode gzip streams (to avoid linking crc code) |
||
1075 | 18-19: 0 (reserved) |
||
1076 | |||
1077 | Operation variations (changes in library functionality): |
||
1078 | 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate |
||
1079 | 21: FASTEST -- deflate algorithm with only one, lowest compression level |
||
1080 | 22,23: 0 (reserved) |
||
1081 | |||
1082 | The sprintf variant used by gzprintf (zero is best): |
||
1083 | 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format |
||
1084 | 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! |
||
1085 | 26: 0 = returns value, 1 = void -- 1 means inferred string length returned |
||
1086 | |||
1087 | Remainder: |
||
1088 | 27-31: 0 (reserved) |
||
1089 | */ |
||
1090 | |||
1091 | |||
1092 | /* utility functions */ |
||
1093 | |||
1094 | /* |
||
1095 | The following utility functions are implemented on top of the basic |
||
1096 | stream-oriented functions. To simplify the interface, some default options |
||
1097 | are assumed (compression level and memory usage, standard memory allocation |
||
1098 | functions). The source code of these utility functions can be modified if |
||
1099 | you need special options. |
||
1100 | */ |
||
1101 | |||
1102 | ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, |
||
1103 | const Bytef *source, uLong sourceLen)); |
||
1104 | /* |
||
1105 | Compresses the source buffer into the destination buffer. sourceLen is |
||
1106 | the byte length of the source buffer. Upon entry, destLen is the total size |
||
1107 | of the destination buffer, which must be at least the value returned by |
||
1108 | compressBound(sourceLen). Upon exit, destLen is the actual size of the |
||
1109 | compressed buffer. |
||
1110 | |||
1111 | compress returns Z_OK if success, Z_MEM_ERROR if there was not |
||
1112 | enough memory, Z_BUF_ERROR if there was not enough room in the output |
||
1113 | buffer. |
||
1114 | */ |
||
1115 | |||
1116 | ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, |
||
1117 | const Bytef *source, uLong sourceLen, |
||
1118 | int level)); |
||
1119 | /* |
||
1120 | Compresses the source buffer into the destination buffer. The level |
||
1121 | parameter has the same meaning as in deflateInit. sourceLen is the byte |
||
1122 | length of the source buffer. Upon entry, destLen is the total size of the |
||
1123 | destination buffer, which must be at least the value returned by |
||
1124 | compressBound(sourceLen). Upon exit, destLen is the actual size of the |
||
1125 | compressed buffer. |
||
1126 | |||
1127 | compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
||
1128 | memory, Z_BUF_ERROR if there was not enough room in the output buffer, |
||
1129 | Z_STREAM_ERROR if the level parameter is invalid. |
||
1130 | */ |
||
1131 | |||
1132 | ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); |
||
1133 | /* |
||
1134 | compressBound() returns an upper bound on the compressed size after |
||
1135 | compress() or compress2() on sourceLen bytes. It would be used before a |
||
1136 | compress() or compress2() call to allocate the destination buffer. |
||
1137 | */ |
||
1138 | |||
1139 | ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, |
||
1140 | const Bytef *source, uLong sourceLen)); |
||
1141 | /* |
||
1142 | Decompresses the source buffer into the destination buffer. sourceLen is |
||
1143 | the byte length of the source buffer. Upon entry, destLen is the total size |
||
1144 | of the destination buffer, which must be large enough to hold the entire |
||
1145 | uncompressed data. (The size of the uncompressed data must have been saved |
||
1146 | previously by the compressor and transmitted to the decompressor by some |
||
1147 | mechanism outside the scope of this compression library.) Upon exit, destLen |
||
1148 | is the actual size of the uncompressed buffer. |
||
1149 | |||
1150 | uncompress returns Z_OK if success, Z_MEM_ERROR if there was not |
||
1151 | enough memory, Z_BUF_ERROR if there was not enough room in the output |
||
1152 | buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. |
||
1153 | */ |
||
1154 | |||
1155 | |||
1156 | /* gzip file access functions */ |
||
1157 | |||
1158 | /* |
||
1159 | This library supports reading and writing files in gzip (.gz) format with |
||
1160 | an interface similar to that of stdio, using the functions that start with |
||
1161 | "gz". The gzip format is different from the zlib format. gzip is a gzip |
||
1162 | wrapper, documented in RFC 1952, wrapped around a deflate stream. |
||
1163 | */ |
||
1164 | |||
1165 | typedef voidp gzFile; /* opaque gzip file descriptor */ |
||
1166 | |||
1167 | /* |
||
1168 | ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); |
||
1169 | |||
1170 | Opens a gzip (.gz) file for reading or writing. The mode parameter is as |
||
1171 | in fopen ("rb" or "wb") but can also include a compression level ("wb9") or |
||
1172 | a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only |
||
1173 | compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F' |
||
1174 | for fixed code compression as in "wb9F". (See the description of |
||
1175 | deflateInit2 for more information about the strategy parameter.) Also "a" |
||
1176 | can be used instead of "w" to request that the gzip stream that will be |
||
1177 | written be appended to the file. "+" will result in an error, since reading |
||
1178 | and writing to the same gzip file is not supported. |
||
1179 | |||
1180 | gzopen can be used to read a file which is not in gzip format; in this |
||
1181 | case gzread will directly read from the file without decompression. |
||
1182 | |||
1183 | gzopen returns NULL if the file could not be opened, if there was |
||
1184 | insufficient memory to allocate the gzFile state, or if an invalid mode was |
||
1185 | specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). |
||
1186 | errno can be checked to determine if the reason gzopen failed was that the |
||
1187 | file could not be opened. |
||
1188 | */ |
||
1189 | |||
1190 | ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); |
||
1191 | /* |
||
1192 | gzdopen associates a gzFile with the file descriptor fd. File descriptors |
||
1193 | are obtained from calls like open, dup, creat, pipe or fileno (if the file |
||
1194 | has been previously opened with fopen). The mode parameter is as in gzopen. |
||
1195 | |||
1196 | The next call of gzclose on the returned gzFile will also close the file |
||
1197 | descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor |
||
1198 | fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, |
||
1199 | mode);. The duplicated descriptor should be saved to avoid a leak, since |
||
1200 | gzdopen does not close fd if it fails. |
||
1201 | |||
1202 | gzdopen returns NULL if there was insufficient memory to allocate the |
||
1203 | gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not |
||
1204 | provided, or '+' was provided), or if fd is -1. The file descriptor is not |
||
1205 | used until the next gz* read, write, seek, or close operation, so gzdopen |
||
1206 | will not detect if fd is invalid (unless fd is -1). |
||
1207 | */ |
||
1208 | |||
1209 | ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size)); |
||
1210 | /* |
||
1211 | Set the internal buffer size used by this library's functions. The |
||
1212 | default buffer size is 8192 bytes. This function must be called after |
||
1213 | gzopen() or gzdopen(), and before any other calls that read or write the |
||
1214 | file. The buffer memory allocation is always deferred to the first read or |
||
1215 | write. Two buffers are allocated, either both of the specified size when |
||
1216 | writing, or one of the specified size and the other twice that size when |
||
1217 | reading. A larger buffer size of, for example, 64K or 128K bytes will |
||
1218 | noticeably increase the speed of decompression (reading). |
||
1219 | |||
1220 | The new buffer size also affects the maximum length for gzprintf(). |
||
1221 | |||
1222 | gzbuffer() returns 0 on success, or -1 on failure, such as being called |
||
1223 | too late. |
||
1224 | */ |
||
1225 | |||
1226 | ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); |
||
1227 | /* |
||
1228 | Dynamically update the compression level or strategy. See the description |
||
1229 | of deflateInit2 for the meaning of these parameters. |
||
1230 | |||
1231 | gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not |
||
1232 | opened for writing. |
||
1233 | */ |
||
1234 | |||
1235 | ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); |
||
1236 | /* |
||
1237 | Reads the given number of uncompressed bytes from the compressed file. If |
||
1238 | the input file was not in gzip format, gzread copies the given number of |
||
1239 | bytes into the buffer. |
||
1240 | |||
1241 | After reaching the end of a gzip stream in the input, gzread will continue |
||
1242 | to read, looking for another gzip stream, or failing that, reading the rest |
||
1243 | of the input file directly without decompression. The entire input file |
||
1244 | will be read if gzread is called until it returns less than the requested |
||
1245 | len. |
||
1246 | |||
1247 | gzread returns the number of uncompressed bytes actually read, less than |
||
1248 | len for end of file, or -1 for error. |
||
1249 | */ |
||
1250 | |||
1251 | ZEXTERN int ZEXPORT gzwrite OF((gzFile file, |
||
1252 | voidpc buf, unsigned len)); |
||
1253 | /* |
||
1254 | Writes the given number of uncompressed bytes into the compressed file. |
||
1255 | gzwrite returns the number of uncompressed bytes written or 0 in case of |
||
1256 | error. |
||
1257 | */ |
||
1258 | |||
1259 | ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); |
||
1260 | /* |
||
1261 | Converts, formats, and writes the arguments to the compressed file under |
||
1262 | control of the format string, as in fprintf. gzprintf returns the number of |
||
1263 | uncompressed bytes actually written, or 0 in case of error. The number of |
||
1264 | uncompressed bytes written is limited to 8191, or one less than the buffer |
||
1265 | size given to gzbuffer(). The caller should assure that this limit is not |
||
1266 | exceeded. If it is exceeded, then gzprintf() will return an error (0) with |
||
1267 | nothing written. In this case, there may also be a buffer overflow with |
||
1268 | unpredictable consequences, which is possible only if zlib was compiled with |
||
1269 | the insecure functions sprintf() or vsprintf() because the secure snprintf() |
||
1270 | or vsnprintf() functions were not available. This can be determined using |
||
1271 | zlibCompileFlags(). |
||
1272 | */ |
||
1273 | |||
1274 | ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); |
||
1275 | /* |
||
1276 | Writes the given null-terminated string to the compressed file, excluding |
||
1277 | the terminating null character. |
||
1278 | |||
1279 | gzputs returns the number of characters written, or -1 in case of error. |
||
1280 | */ |
||
1281 | |||
1282 | ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); |
||
1283 | /* |
||
1284 | Reads bytes from the compressed file until len-1 characters are read, or a |
||
1285 | newline character is read and transferred to buf, or an end-of-file |
||
1286 | condition is encountered. If any characters are read or if len == 1, the |
||
1287 | string is terminated with a null character. If no characters are read due |
||
1288 | to an end-of-file or len < 1, then the buffer is left untouched. |
||
1289 | |||
1290 | gzgets returns buf which is a null-terminated string, or it returns NULL |
||
1291 | for end-of-file or in case of error. If there was an error, the contents at |
||
1292 | buf are indeterminate. |
||
1293 | */ |
||
1294 | |||
1295 | ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); |
||
1296 | /* |
||
1297 | Writes c, converted to an unsigned char, into the compressed file. gzputc |
||
1298 | returns the value that was written, or -1 in case of error. |
||
1299 | */ |
||
1300 | |||
1301 | ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); |
||
1302 | /* |
||
1303 | Reads one byte from the compressed file. gzgetc returns this byte or -1 |
||
1304 | in case of end of file or error. |
||
1305 | */ |
||
1306 | |||
1307 | ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); |
||
1308 | /* |
||
1309 | Push one character back onto the stream to be read as the first character |
||
1310 | on the next read. At least one character of push-back is allowed. |
||
1311 | gzungetc() returns the character pushed, or -1 on failure. gzungetc() will |
||
1312 | fail if c is -1, and may fail if a character has been pushed but not read |
||
1313 | yet. If gzungetc is used immediately after gzopen or gzdopen, at least the |
||
1314 | output buffer size of pushed characters is allowed. (See gzbuffer above.) |
||
1315 | The pushed character will be discarded if the stream is repositioned with |
||
1316 | gzseek() or gzrewind(). |
||
1317 | */ |
||
1318 | |||
1319 | ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); |
||
1320 | /* |
||
1321 | Flushes all pending output into the compressed file. The parameter flush |
||
1322 | is as in the deflate() function. The return value is the zlib error number |
||
1323 | (see function gzerror below). gzflush is only permitted when writing. |
||
1324 | |||
1325 | If the flush parameter is Z_FINISH, the remaining data is written and the |
||
1326 | gzip stream is completed in the output. If gzwrite() is called again, a new |
||
1327 | gzip stream will be started in the output. gzread() is able to read such |
||
1328 | concatented gzip streams. |
||
1329 | |||
1330 | gzflush should be called only when strictly necessary because it will |
||
1331 | degrade compression if called too often. |
||
1332 | */ |
||
1333 | |||
1334 | /* |
||
1335 | ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, |
||
1336 | z_off_t offset, int whence)); |
||
1337 | |||
1338 | Sets the starting position for the next gzread or gzwrite on the given |
||
1339 | compressed file. The offset represents a number of bytes in the |
||
1340 | uncompressed data stream. The whence parameter is defined as in lseek(2); |
||
1341 | the value SEEK_END is not supported. |
||
1342 | |||
1343 | If the file is opened for reading, this function is emulated but can be |
||
1344 | extremely slow. If the file is opened for writing, only forward seeks are |
||
1345 | supported; gzseek then compresses a sequence of zeroes up to the new |
||
1346 | starting position. |
||
1347 | |||
1348 | gzseek returns the resulting offset location as measured in bytes from |
||
1349 | the beginning of the uncompressed stream, or -1 in case of error, in |
||
1350 | particular if the file is opened for writing and the new starting position |
||
1351 | would be before the current position. |
||
1352 | */ |
||
1353 | |||
1354 | ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); |
||
1355 | /* |
||
1356 | Rewinds the given file. This function is supported only for reading. |
||
1357 | |||
1358 | gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) |
||
1359 | */ |
||
1360 | |||
1361 | /* |
||
1362 | ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); |
||
1363 | |||
1364 | Returns the starting position for the next gzread or gzwrite on the given |
||
1365 | compressed file. This position represents a number of bytes in the |
||
1366 | uncompressed data stream, and is zero when starting, even if appending or |
||
1367 | reading a gzip stream from the middle of a file using gzdopen(). |
||
1368 | |||
1369 | gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) |
||
1370 | */ |
||
1371 | |||
1372 | /* |
||
1373 | ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); |
||
1374 | |||
1375 | Returns the current offset in the file being read or written. This offset |
||
1376 | includes the count of bytes that precede the gzip stream, for example when |
||
1377 | appending or when using gzdopen() for reading. When reading, the offset |
||
1378 | does not include as yet unused buffered input. This information can be used |
||
1379 | for a progress indicator. On error, gzoffset() returns -1. |
||
1380 | */ |
||
1381 | |||
1382 | ZEXTERN int ZEXPORT gzeof OF((gzFile file)); |
||
1383 | /* |
||
1384 | Returns true (1) if the end-of-file indicator has been set while reading, |
||
1385 | false (0) otherwise. Note that the end-of-file indicator is set only if the |
||
1386 | read tried to go past the end of the input, but came up short. Therefore, |
||
1387 | just like feof(), gzeof() may return false even if there is no more data to |
||
1388 | read, in the event that the last read request was for the exact number of |
||
1389 | bytes remaining in the input file. This will happen if the input file size |
||
1390 | is an exact multiple of the buffer size. |
||
1391 | |||
1392 | If gzeof() returns true, then the read functions will return no more data, |
||
1393 | unless the end-of-file indicator is reset by gzclearerr() and the input file |
||
1394 | has grown since the previous end of file was detected. |
||
1395 | */ |
||
1396 | |||
1397 | ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); |
||
1398 | /* |
||
1399 | Returns true (1) if file is being copied directly while reading, or false |
||
1400 | (0) if file is a gzip stream being decompressed. This state can change from |
||
1401 | false to true while reading the input file if the end of a gzip stream is |
||
1402 | reached, but is followed by data that is not another gzip stream. |
||
1403 | |||
1404 | If the input file is empty, gzdirect() will return true, since the input |
||
1405 | does not contain a gzip stream. |
||
1406 | |||
1407 | If gzdirect() is used immediately after gzopen() or gzdopen() it will |
||
1408 | cause buffers to be allocated to allow reading the file to determine if it |
||
1409 | is a gzip file. Therefore if gzbuffer() is used, it should be called before |
||
1410 | gzdirect(). |
||
1411 | */ |
||
1412 | |||
1413 | ZEXTERN int ZEXPORT gzclose OF((gzFile file)); |
||
1414 | /* |
||
1415 | Flushes all pending output if necessary, closes the compressed file and |
||
1416 | deallocates the (de)compression state. Note that once file is closed, you |
||
1417 | cannot call gzerror with file, since its structures have been deallocated. |
||
1418 | gzclose must not be called more than once on the same file, just as free |
||
1419 | must not be called more than once on the same allocation. |
||
1420 | |||
1421 | gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a |
||
1422 | file operation error, or Z_OK on success. |
||
1423 | */ |
||
1424 | |||
1425 | ZEXTERN int ZEXPORT gzclose_r OF((gzFile file)); |
||
1426 | ZEXTERN int ZEXPORT gzclose_w OF((gzFile file)); |
||
1427 | /* |
||
1428 | Same as gzclose(), but gzclose_r() is only for use when reading, and |
||
1429 | gzclose_w() is only for use when writing or appending. The advantage to |
||
1430 | using these instead of gzclose() is that they avoid linking in zlib |
||
1431 | compression or decompression code that is not used when only reading or only |
||
1432 | writing respectively. If gzclose() is used, then both compression and |
||
1433 | decompression code will be included the application when linking to a static |
||
1434 | zlib library. |
||
1435 | */ |
||
1436 | |||
1437 | ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); |
||
1438 | /* |
||
1439 | Returns the error message for the last error which occurred on the given |
||
1440 | compressed file. errnum is set to zlib error number. If an error occurred |
||
1441 | in the file system and not in the compression library, errnum is set to |
||
1442 | Z_ERRNO and the application may consult errno to get the exact error code. |
||
1443 | |||
1444 | The application must not modify the returned string. Future calls to |
||
1445 | this function may invalidate the previously returned string. If file is |
||
1446 | closed, then the string previously returned by gzerror will no longer be |
||
1447 | available. |
||
1448 | |||
1449 | gzerror() should be used to distinguish errors from end-of-file for those |
||
1450 | functions above that do not distinguish those cases in their return values. |
||
1451 | */ |
||
1452 | |||
1453 | ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); |
||
1454 | /* |
||
1455 | Clears the error and end-of-file flags for file. This is analogous to the |
||
1456 | clearerr() function in stdio. This is useful for continuing to read a gzip |
||
1457 | file that is being written concurrently. |
||
1458 | */ |
||
1459 | |||
1460 | |||
1461 | /* checksum functions */ |
||
1462 | |||
1463 | /* |
||
1464 | These functions are not related to compression but are exported |
||
1465 | anyway because they might be useful in applications using the compression |
||
1466 | library. |
||
1467 | */ |
||
1468 | |||
1469 | ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); |
||
1470 | /* |
||
1471 | Update a running Adler-32 checksum with the bytes buf[0..len-1] and |
||
1472 | return the updated checksum. If buf is Z_NULL, this function returns the |
||
1473 | required initial value for the checksum. |
||
1474 | |||
1475 | An Adler-32 checksum is almost as reliable as a CRC32 but can be computed |
||
1476 | much faster. |
||
1477 | |||
1478 | Usage example: |
||
1479 | |||
1480 | uLong adler = adler32(0L, Z_NULL, 0); |
||
1481 | |||
1482 | while (read_buffer(buffer, length) != EOF) { |
||
1483 | adler = adler32(adler, buffer, length); |
||
1484 | } |
||
1485 | if (adler != original_adler) error(); |
||
1486 | */ |
||
1487 | |||
1488 | /* |
||
1489 | ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, |
||
1490 | z_off_t len2)); |
||
1491 | |||
1492 | Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 |
||
1493 | and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for |
||
1494 | each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of |
||
1495 | seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. |
||
1496 | */ |
||
1497 | |||
1498 | ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); |
||
1499 | /* |
||
1500 | Update a running CRC-32 with the bytes buf[0..len-1] and return the |
||
1501 | updated CRC-32. If buf is Z_NULL, this function returns the required |
||
1502 | initial value for the for the crc. Pre- and post-conditioning (one's |
||
1503 | complement) is performed within this function so it shouldn't be done by the |
||
1504 | application. |
||
1505 | |||
1506 | Usage example: |
||
1507 | |||
1508 | uLong crc = crc32(0L, Z_NULL, 0); |
||
1509 | |||
1510 | while (read_buffer(buffer, length) != EOF) { |
||
1511 | crc = crc32(crc, buffer, length); |
||
1512 | } |
||
1513 | if (crc != original_crc) error(); |
||
1514 | */ |
||
1515 | |||
1516 | /* |
||
1517 | ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); |
||
1518 | |||
1519 | Combine two CRC-32 check values into one. For two sequences of bytes, |
||
1520 | seq1 and seq2 with lengths len1 and len2, CRC-32 check values were |
||
1521 | calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 |
||
1522 | check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and |
||
1523 | len2. |
||
1524 | */ |
||
1525 | |||
1526 | |||
1527 | /* various hacks, don't look :) */ |
||
1528 | |||
1529 | /* deflateInit and inflateInit are macros to allow checking the zlib version |
||
1530 | * and the compiler's view of z_stream: |
||
1531 | */ |
||
1532 | ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, |
||
1533 | const char *version, int stream_size)); |
||
1534 | ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, |
||
1535 | const char *version, int stream_size)); |
||
1536 | ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, |
||
1537 | int windowBits, int memLevel, |
||
1538 | int strategy, const char *version, |
||
1539 | int stream_size)); |
||
1540 | ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, |
||
1541 | const char *version, int stream_size)); |
||
1542 | ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, |
||
1543 | unsigned char FAR *window, |
||
1544 | const char *version, |
||
1545 | int stream_size)); |
||
1546 | #define deflateInit(strm, level) \ |
||
1547 | deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) |
||
1548 | #define inflateInit(strm) \ |
||
1549 | inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) |
||
1550 | #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ |
||
1551 | deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ |
||
1552 | (strategy), ZLIB_VERSION, sizeof(z_stream)) |
||
1553 | #define inflateInit2(strm, windowBits) \ |
||
1554 | inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) |
||
1555 | #define inflateBackInit(strm, windowBits, window) \ |
||
1556 | inflateBackInit_((strm), (windowBits), (window), \ |
||
1557 | ZLIB_VERSION, sizeof(z_stream)) |
||
1558 | |||
1559 | /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or |
||
1560 | * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if |
||
1561 | * both are true, the application gets the *64 functions, and the regular |
||
1562 | * functions are changed to 64 bits) -- in case these are set on systems |
||
1563 | * without large file support, _LFS64_LARGEFILE must also be true |
||
1564 | */ |
||
1565 | #if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0 |
||
1566 | ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); |
||
1567 | ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); |
||
1568 | ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); |
||
1569 | ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); |
||
1570 | ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); |
||
1571 | ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); |
||
1572 | #endif |
||
1573 | |||
1574 | #if !defined(ZLIB_INTERNAL) && _FILE_OFFSET_BITS-0 == 64 && _LFS64_LARGEFILE-0 |
||
1575 | # define gzopen gzopen64 |
||
1576 | # define gzseek gzseek64 |
||
1577 | # define gztell gztell64 |
||
1578 | # define gzoffset gzoffset64 |
||
1579 | # define adler32_combine adler32_combine64 |
||
1580 | # define crc32_combine crc32_combine64 |
||
1581 | # ifdef _LARGEFILE64_SOURCE |
||
1582 | ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); |
||
1583 | ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int)); |
||
1584 | ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile)); |
||
1585 | ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile)); |
||
1586 | ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t)); |
||
1587 | ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t)); |
||
1588 | # endif |
||
1589 | #else |
||
1590 | ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); |
||
1591 | ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); |
||
1592 | ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); |
||
1593 | ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); |
||
1594 | ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); |
||
1595 | ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); |
||
1596 | #endif |
||
1597 | |||
1598 | /* hack for buggy compilers */ |
||
1599 | #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) |
||
1600 | struct internal_state {int dummy;}; |
||
1601 | #endif |
||
1602 | |||
1603 | /* undocumented functions */ |
||
1604 | ZEXTERN const char * ZEXPORT zError OF((int)); |
||
1605 | ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); |
||
1606 | ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); |
||
1607 | ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); |
||
1608 | |||
1609 | #ifdef __cplusplus |
||
1610 | } |
||
1611 | #endif |
||
1612 | |||
1613 | #endif /* ZLIB_H */>><>> |