1 /* zlib.h -- interface of the 'zlib' general purpose compression library |
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2 version 1.1.4, March 11th, 2002 |
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3 |
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4 Copyright (C) 1995-2002 Jean-loup Gailly and Mark Adler |
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5 |
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6 This software is provided 'as-is', without any express or implied |
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7 warranty. In no event will the authors be held liable for any damages |
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8 arising from the use of this software. |
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9 |
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10 Permission is granted to anyone to use this software for any purpose, |
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11 including commercial applications, and to alter it and redistribute it |
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12 freely, subject to the following restrictions: |
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13 |
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14 1. The origin of this software must not be misrepresented; you must not |
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15 claim that you wrote the original software. If you use this software |
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16 in a product, an acknowledgment in the product documentation would be |
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17 appreciated but is not required. |
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18 2. Altered source versions must be plainly marked as such, and must not be |
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19 misrepresented as being the original software. |
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20 3. This notice may not be removed or altered from any source distribution. |
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21 |
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22 Jean-loup Gailly Mark Adler |
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23 jloup@gzip.org madler@alumni.caltech.edu |
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24 |
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25 |
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26 The data format used by the zlib library is described by RFCs (Request for |
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27 Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt |
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28 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format). |
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29 */ |
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30 |
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31 #ifndef _ZLIB_H |
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32 #define _ZLIB_H |
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33 |
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34 #include "zconf.h" |
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35 |
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36 #ifdef __cplusplus |
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37 extern "C" { |
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38 #endif |
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39 |
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40 #define ZLIB_VERSION "1.1.4" |
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41 |
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42 /* |
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43 The 'zlib' compression library provides in-memory compression and |
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44 decompression functions, including integrity checks of the uncompressed |
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45 data. This version of the library supports only one compression method |
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46 (deflation) but other algorithms will be added later and will have the same |
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47 stream interface. |
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48 |
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49 Compression can be done in a single step if the buffers are large |
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50 enough (for example if an input file is mmap'ed), or can be done by |
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51 repeated calls of the compression function. In the latter case, the |
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52 application must provide more input and/or consume the output |
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53 (providing more output space) before each call. |
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54 |
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55 The library also supports reading and writing files in gzip (.gz) format |
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56 with an interface similar to that of stdio. |
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57 |
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58 The library does not install any signal handler. The decoder checks |
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59 the consistency of the compressed data, so the library should never |
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60 crash even in case of corrupted input. |
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61 */ |
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62 |
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63 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); |
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64 typedef void (*free_func) OF((voidpf opaque, voidpf address)); |
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65 |
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66 struct internal_state; |
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67 |
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68 typedef struct z_stream_s { |
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69 Bytef *next_in; /* next input byte */ |
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70 uInt avail_in; /* number of bytes available at next_in */ |
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71 uLong total_in; /* total nb of input bytes read so far */ |
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72 |
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73 Bytef *next_out; /* next output byte should be put there */ |
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74 uInt avail_out; /* remaining free space at next_out */ |
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75 uLong total_out; /* total nb of bytes output so far */ |
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76 |
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77 char *msg; /* last error message, NULL if no error */ |
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78 struct internal_state FAR *state; /* not visible by applications */ |
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79 |
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80 alloc_func zalloc; /* used to allocate the internal state */ |
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81 free_func zfree; /* used to free the internal state */ |
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82 voidpf opaque; /* private data object passed to zalloc and zfree */ |
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83 |
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84 int data_type; /* best guess about the data type: ascii or binary */ |
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85 uLong adler; /* adler32 value of the uncompressed data */ |
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86 uLong reserved; /* reserved for future use */ |
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87 } z_stream; |
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88 |
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89 typedef z_stream FAR *z_streamp; |
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90 |
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91 /* |
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92 The application must update next_in and avail_in when avail_in has |
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93 dropped to zero. It must update next_out and avail_out when avail_out |
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94 has dropped to zero. The application must initialize zalloc, zfree and |
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95 opaque before calling the init function. All other fields are set by the |
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96 compression library and must not be updated by the application. |
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97 |
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98 The opaque value provided by the application will be passed as the first |
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99 parameter for calls of zalloc and zfree. This can be useful for custom |
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100 memory management. The compression library attaches no meaning to the |
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101 opaque value. |
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102 |
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103 zalloc must return Z_NULL if there is not enough memory for the object. |
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104 If zlib is used in a multi-threaded application, zalloc and zfree must be |
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105 thread safe. |
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106 |
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107 On 16-bit systems, the functions zalloc and zfree must be able to allocate |
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108 exactly 65536 bytes, but will not be required to allocate more than this |
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109 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, |
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110 pointers returned by zalloc for objects of exactly 65536 bytes *must* |
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111 have their offset normalized to zero. The default allocation function |
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112 provided by this library ensures this (see zutil.c). To reduce memory |
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113 requirements and avoid any allocation of 64K objects, at the expense of |
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114 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). |
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115 |
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116 The fields total_in and total_out can be used for statistics or |
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117 progress reports. After compression, total_in holds the total size of |
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118 the uncompressed data and may be saved for use in the decompressor |
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119 (particularly if the decompressor wants to decompress everything in |
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120 a single step). |
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121 */ |
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122 |
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123 /* constants */ |
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124 |
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125 #define Z_NO_FLUSH 0 |
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126 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ |
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127 #define Z_SYNC_FLUSH 2 |
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128 #define Z_FULL_FLUSH 3 |
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129 #define Z_FINISH 4 |
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130 /* Allowed flush values; see deflate() below for details */ |
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131 |
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132 #define Z_OK 0 |
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133 #define Z_STREAM_END 1 |
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134 #define Z_NEED_DICT 2 |
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135 #define Z_ERRNO (-1) |
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136 #define Z_STREAM_ERROR (-2) |
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137 #define Z_DATA_ERROR (-3) |
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138 #define Z_MEM_ERROR (-4) |
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139 #define Z_BUF_ERROR (-5) |
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140 #define Z_VERSION_ERROR (-6) |
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141 /* Return codes for the compression/decompression functions. Negative |
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142 * values are errors, positive values are used for special but normal events. |
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143 */ |
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144 |
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145 #define Z_NO_COMPRESSION 0 |
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146 #define Z_BEST_SPEED 1 |
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147 #define Z_BEST_COMPRESSION 9 |
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148 #define Z_DEFAULT_COMPRESSION (-1) |
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149 /* compression levels */ |
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150 |
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151 #define Z_FILTERED 1 |
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152 #define Z_HUFFMAN_ONLY 2 |
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153 #define Z_DEFAULT_STRATEGY 0 |
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154 /* compression strategy; see deflateInit2() below for details */ |
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155 |
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156 #define Z_BINARY 0 |
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157 #define Z_ASCII 1 |
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158 #define Z_UNKNOWN 2 |
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159 /* Possible values of the data_type field */ |
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160 |
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161 #define Z_DEFLATED 8 |
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162 /* The deflate compression method (the only one supported in this version) */ |
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163 |
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164 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ |
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165 |
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166 |
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167 /* basic functions */ |
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168 |
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169 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. |
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170 If the first character differs, the library code actually used is |
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171 not compatible with the zlib.h header file used by the application. |
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172 This check is automatically made by deflateInit and inflateInit. |
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173 */ |
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174 |
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175 /* |
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176 ZEXTERN(int) deflateInit OF((z_streamp strm, int level)); |
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177 |
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178 Initializes the internal stream state for compression. The fields |
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179 zalloc, zfree and opaque must be initialized before by the caller. |
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180 If zalloc and zfree are set to Z_NULL, deflateInit updates them to |
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181 use default allocation functions. |
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182 |
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183 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: |
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184 1 gives best speed, 9 gives best compression, 0 gives no compression at |
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185 all (the input data is simply copied a block at a time). |
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186 Z_DEFAULT_COMPRESSION requests a default compromise between speed and |
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187 compression (currently equivalent to level 6). |
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188 |
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189 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not |
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190 enough memory, Z_STREAM_ERROR if level is not a valid compression level, |
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191 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible |
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192 with the version assumed by the caller (ZLIB_VERSION). |
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193 msg is set to null if there is no error message. deflateInit does not |
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194 perform any compression: this will be done by deflate(). |
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195 */ |
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196 |
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197 |
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198 /* |
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199 deflate compresses as much data as possible, and stops when the input |
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200 buffer becomes empty or the output buffer becomes full. It may introduce some |
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201 output latency (reading input without producing any output) except when |
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202 forced to flush. |
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203 |
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204 The detailed semantics are as follows. deflate performs one or both of the |
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205 following actions: |
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206 |
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207 - Compress more input starting at next_in and update next_in and avail_in |
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208 accordingly. If not all input can be processed (because there is not |
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209 enough room in the output buffer), next_in and avail_in are updated and |
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210 processing will resume at this point for the next call of deflate(). |
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211 |
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212 - Provide more output starting at next_out and update next_out and avail_out |
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213 accordingly. This action is forced if the parameter flush is non zero. |
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214 Forcing flush frequently degrades the compression ratio, so this parameter |
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215 should be set only when necessary (in interactive applications). |
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216 Some output may be provided even if flush is not set. |
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217 |
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218 Before the call of deflate(), the application should ensure that at least |
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219 one of the actions is possible, by providing more input and/or consuming |
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220 more output, and updating avail_in or avail_out accordingly; avail_out |
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221 should never be zero before the call. The application can consume the |
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222 compressed output when it wants, for example when the output buffer is full |
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223 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK |
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224 and with zero avail_out, it must be called again after making room in the |
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225 output buffer because there might be more output pending. |
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226 |
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227 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is |
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228 flushed to the output buffer and the output is aligned on a byte boundary, so |
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229 that the decompressor can get all input data available so far. (In particular |
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230 avail_in is zero after the call if enough output space has been provided |
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231 before the call.) Flushing may degrade compression for some compression |
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232 algorithms and so it should be used only when necessary. |
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233 |
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234 If flush is set to Z_FULL_FLUSH, all output is flushed as with |
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235 Z_SYNC_FLUSH, and the compression state is reset so that decompression can |
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236 restart from this point if previous compressed data has been damaged or if |
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237 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade |
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238 the compression. |
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239 |
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240 If deflate returns with avail_out == 0, this function must be called again |
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241 with the same value of the flush parameter and more output space (updated |
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242 avail_out), until the flush is complete (deflate returns with non-zero |
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243 avail_out). |
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244 |
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245 If the parameter flush is set to Z_FINISH, pending input is processed, |
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246 pending output is flushed and deflate returns with Z_STREAM_END if there |
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247 was enough output space; if deflate returns with Z_OK, this function must be |
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248 called again with Z_FINISH and more output space (updated avail_out) but no |
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249 more input data, until it returns with Z_STREAM_END or an error. After |
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250 deflate has returned Z_STREAM_END, the only possible operations on the |
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251 stream are deflateReset or deflateEnd. |
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252 |
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253 Z_FINISH can be used immediately after deflateInit if all the compression |
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254 is to be done in a single step. In this case, avail_out must be at least |
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255 0.1% larger than avail_in plus 12 bytes. If deflate does not return |
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256 Z_STREAM_END, then it must be called again as described above. |
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257 |
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258 deflate() sets strm->adler to the adler32 checksum of all input read |
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259 so far (that is, total_in bytes). |
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260 |
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261 deflate() may update data_type if it can make a good guess about |
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262 the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered |
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263 binary. This field is only for information purposes and does not affect |
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264 the compression algorithm in any manner. |
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265 |
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266 deflate() returns Z_OK if some progress has been made (more input |
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267 processed or more output produced), Z_STREAM_END if all input has been |
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268 consumed and all output has been produced (only when flush is set to |
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269 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example |
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270 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible |
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271 (for example avail_in or avail_out was zero). |
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272 */ |
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273 |
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274 |
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275 /* |
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276 All dynamically allocated data structures for this stream are freed. |
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277 This function discards any unprocessed input and does not flush any |
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278 pending output. |
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279 |
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280 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the |
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281 stream state was inconsistent, Z_DATA_ERROR if the stream was freed |
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282 prematurely (some input or output was discarded). In the error case, |
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283 msg may be set but then points to a static string (which must not be |
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284 deallocated). |
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285 */ |
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286 |
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287 |
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288 /* |
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289 ZEXTERN(int) inflateInit OF((z_streamp strm)); |
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290 |
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291 Initializes the internal stream state for decompression. The fields |
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292 next_in, avail_in, zalloc, zfree and opaque must be initialized before by |
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293 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact |
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294 value depends on the compression method), inflateInit determines the |
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295 compression method from the zlib header and allocates all data structures |
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296 accordingly; otherwise the allocation will be deferred to the first call of |
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297 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to |
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298 use default allocation functions. |
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299 |
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300 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough |
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301 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the |
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302 version assumed by the caller. msg is set to null if there is no error |
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303 message. inflateInit does not perform any decompression apart from reading |
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304 the zlib header if present: this will be done by inflate(). (So next_in and |
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305 avail_in may be modified, but next_out and avail_out are unchanged.) |
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306 */ |
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307 |
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308 |
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309 ZEXTERN(int) inflate OF((z_streamp strm, int flush)); |
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310 /* |
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311 inflate decompresses as much data as possible, and stops when the input |
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312 buffer becomes empty or the output buffer becomes full. It may some |
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313 introduce some output latency (reading input without producing any output) |
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314 except when forced to flush. |
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315 |
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316 The detailed semantics are as follows. inflate performs one or both of the |
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317 following actions: |
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318 |
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319 - Decompress more input starting at next_in and update next_in and avail_in |
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320 accordingly. If not all input can be processed (because there is not |
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321 enough room in the output buffer), next_in is updated and processing |
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322 will resume at this point for the next call of inflate(). |
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323 |
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324 - Provide more output starting at next_out and update next_out and avail_out |
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325 accordingly. inflate() provides as much output as possible, until there |
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326 is no more input data or no more space in the output buffer (see below |
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327 about the flush parameter). |
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328 |
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329 Before the call of inflate(), the application should ensure that at least |
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330 one of the actions is possible, by providing more input and/or consuming |
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331 more output, and updating the next_* and avail_* values accordingly. |
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332 The application can consume the uncompressed output when it wants, for |
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333 example when the output buffer is full (avail_out == 0), or after each |
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334 call of inflate(). If inflate returns Z_OK and with zero avail_out, it |
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335 must be called again after making room in the output buffer because there |
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336 might be more output pending. |
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337 |
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338 If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much |
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339 output as possible to the output buffer. The flushing behavior of inflate is |
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340 not specified for values of the flush parameter other than Z_SYNC_FLUSH |
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341 and Z_FINISH, but the current implementation actually flushes as much output |
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342 as possible anyway. |
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343 |
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344 inflate() should normally be called until it returns Z_STREAM_END or an |
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345 error. However if all decompression is to be performed in a single step |
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346 (a single call of inflate), the parameter flush should be set to |
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347 Z_FINISH. In this case all pending input is processed and all pending |
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348 output is flushed; avail_out must be large enough to hold all the |
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349 uncompressed data. (The size of the uncompressed data may have been saved |
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350 by the compressor for this purpose.) The next operation on this stream must |
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351 be inflateEnd to deallocate the decompression state. The use of Z_FINISH |
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352 is never required, but can be used to inform inflate that a faster routine |
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353 may be used for the single inflate() call. |
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354 |
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355 If a preset dictionary is needed at this point (see inflateSetDictionary |
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356 below), inflate sets strm-adler to the adler32 checksum of the |
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357 dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise |
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358 it sets strm->adler to the adler32 checksum of all output produced |
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359 so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or |
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360 an error code as described below. At the end of the stream, inflate() |
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361 checks that its computed adler32 checksum is equal to that saved by the |
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362 compressor and returns Z_STREAM_END only if the checksum is correct. |
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363 |
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364 inflate() returns Z_OK if some progress has been made (more input processed |
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365 or more output produced), Z_STREAM_END if the end of the compressed data has |
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366 been reached and all uncompressed output has been produced, Z_NEED_DICT if a |
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367 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was |
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368 corrupted (input stream not conforming to the zlib format or incorrect |
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369 adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent |
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370 (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not |
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371 enough memory, Z_BUF_ERROR if no progress is possible or if there was not |
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372 enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR |
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373 case, the application may then call inflateSync to look for a good |
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374 compression block. |
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375 */ |
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376 |
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377 |
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378 ZEXTERN(int) inflateEnd OF((z_streamp strm)); |
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379 /* |
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380 All dynamically allocated data structures for this stream are freed. |
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381 This function discards any unprocessed input and does not flush any |
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382 pending output. |
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383 |
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384 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state |
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385 was inconsistent. In the error case, msg may be set but then points to a |
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386 static string (which must not be deallocated). |
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387 */ |
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388 |
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389 /* Advanced functions */ |
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390 |
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391 /* |
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392 The following functions are needed only in some special applications. |
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393 */ |
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394 |
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395 /* |
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396 ZEXTERN(int) deflateInit2 OF((z_streamp strm, |
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397 int level, |
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398 int method, |
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399 int windowBits, |
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400 int memLevel, |
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401 int strategy)); |
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402 |
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403 This is another version of deflateInit with more compression options. The |
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404 fields next_in, zalloc, zfree and opaque must be initialized before by |
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405 the caller. |
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406 |
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407 The method parameter is the compression method. It must be Z_DEFLATED in |
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408 this version of the library. |
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409 |
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410 The windowBits parameter is the base two logarithm of the window size |
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411 (the size of the history buffer). It should be in the range 8..15 for this |
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412 version of the library. Larger values of this parameter result in better |
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413 compression at the expense of memory usage. The default value is 15 if |
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414 deflateInit is used instead. |
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415 |
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416 The memLevel parameter specifies how much memory should be allocated |
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417 for the internal compression state. memLevel=1 uses minimum memory but |
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418 is slow and reduces compression ratio; memLevel=9 uses maximum memory |
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419 for optimal speed. The default value is 8. See zconf.h for total memory |
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420 usage as a function of windowBits and memLevel. |
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421 |
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422 The strategy parameter is used to tune the compression algorithm. Use the |
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423 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a |
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424 filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no |
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425 string match). Filtered data consists mostly of small values with a |
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426 somewhat random distribution. In this case, the compression algorithm is |
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427 tuned to compress them better. The effect of Z_FILTERED is to force more |
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428 Huffman coding and less string matching; it is somewhat intermediate |
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429 between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects |
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430 the compression ratio but not the correctness of the compressed output even |
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431 if it is not set appropriately. |
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432 |
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433 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
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434 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid |
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435 method). msg is set to null if there is no error message. deflateInit2 does |
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436 not perform any compression: this will be done by deflate(). |
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437 */ |
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438 |
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439 /* |
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440 Initializes the compression dictionary from the given byte sequence |
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441 without producing any compressed output. This function must be called |
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442 immediately after deflateInit, deflateInit2 or deflateReset, before any |
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443 call of deflate. The compressor and decompressor must use exactly the same |
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444 dictionary (see inflateSetDictionary). |
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445 |
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446 The dictionary should consist of strings (byte sequences) that are likely |
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447 to be encountered later in the data to be compressed, with the most commonly |
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448 used strings preferably put towards the end of the dictionary. Using a |
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449 dictionary is most useful when the data to be compressed is short and can be |
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450 predicted with good accuracy; the data can then be compressed better than |
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451 with the default empty dictionary. |
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452 |
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453 Depending on the size of the compression data structures selected by |
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454 deflateInit or deflateInit2, a part of the dictionary may in effect be |
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455 discarded, for example if the dictionary is larger than the window size in |
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456 deflate or deflate2. Thus the strings most likely to be useful should be |
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457 put at the end of the dictionary, not at the front. |
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458 |
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459 Upon return of this function, strm->adler is set to the Adler32 value |
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460 of the dictionary; the decompressor may later use this value to determine |
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461 which dictionary has been used by the compressor. (The Adler32 value |
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462 applies to the whole dictionary even if only a subset of the dictionary is |
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463 actually used by the compressor.) |
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464 |
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465 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a |
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466 parameter is invalid (such as NULL dictionary) or the stream state is |
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467 inconsistent (for example if deflate has already been called for this stream |
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468 or if the compression method is bsort). deflateSetDictionary does not |
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469 perform any compression: this will be done by deflate(). |
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470 */ |
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471 |
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472 /* |
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473 Sets the destination stream as a complete copy of the source stream. |
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474 |
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475 This function can be useful when several compression strategies will be |
|
476 tried, for example when there are several ways of pre-processing the input |
|
477 data with a filter. The streams that will be discarded should then be freed |
|
478 by calling deflateEnd. Note that deflateCopy duplicates the internal |
|
479 compression state which can be quite large, so this strategy is slow and |
|
480 can consume lots of memory. |
|
481 |
|
482 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
|
483 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
|
484 (such as zalloc being NULL). msg is left unchanged in both source and |
|
485 destination. |
|
486 */ |
|
487 |
|
488 /* |
|
489 This function is equivalent to deflateEnd followed by deflateInit, |
|
490 but does not free and reallocate all the internal compression state. |
|
491 The stream will keep the same compression level and any other attributes |
|
492 that may have been set by deflateInit2. |
|
493 |
|
494 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
|
495 stream state was inconsistent (such as zalloc or state being NULL). |
|
496 */ |
|
497 |
|
498 /* |
|
499 Dynamically update the compression level and compression strategy. The |
|
500 interpretation of level and strategy is as in deflateInit2. This can be |
|
501 used to switch between compression and straight copy of the input data, or |
|
502 to switch to a different kind of input data requiring a different |
|
503 strategy. If the compression level is changed, the input available so far |
|
504 is compressed with the old level (and may be flushed); the new level will |
|
505 take effect only at the next call of deflate(). |
|
506 |
|
507 Before the call of deflateParams, the stream state must be set as for |
|
508 a call of deflate(), since the currently available input may have to |
|
509 be compressed and flushed. In particular, strm->avail_out must be non-zero. |
|
510 |
|
511 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source |
|
512 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR |
|
513 if strm->avail_out was zero. |
|
514 */ |
|
515 |
|
516 /* |
|
517 ZEXTERN(int) inflateInit2 OF((z_streamp strm, |
|
518 int windowBits)); |
|
519 |
|
520 This is another version of inflateInit with an extra parameter. The |
|
521 fields next_in, avail_in, zalloc, zfree and opaque must be initialized |
|
522 before by the caller. |
|
523 |
|
524 The windowBits parameter is the base two logarithm of the maximum window |
|
525 size (the size of the history buffer). It should be in the range 8..15 for |
|
526 this version of the library. The default value is 15 if inflateInit is used |
|
527 instead. If a compressed stream with a larger window size is given as |
|
528 input, inflate() will return with the error code Z_DATA_ERROR instead of |
|
529 trying to allocate a larger window. |
|
530 |
|
531 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
|
532 memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative |
|
533 memLevel). msg is set to null if there is no error message. inflateInit2 |
|
534 does not perform any decompression apart from reading the zlib header if |
|
535 present: this will be done by inflate(). (So next_in and avail_in may be |
|
536 modified, but next_out and avail_out are unchanged.) |
|
537 */ |
|
538 |
|
539 /* |
|
540 Initializes the decompression dictionary from the given uncompressed byte |
|
541 sequence. This function must be called immediately after a call of inflate |
|
542 if this call returned Z_NEED_DICT. The dictionary chosen by the compressor |
|
543 can be determined from the Adler32 value returned by this call of |
|
544 inflate. The compressor and decompressor must use exactly the same |
|
545 dictionary (see deflateSetDictionary). |
|
546 |
|
547 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a |
|
548 parameter is invalid (such as NULL dictionary) or the stream state is |
|
549 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the |
|
550 expected one (incorrect Adler32 value). inflateSetDictionary does not |
|
551 perform any decompression: this will be done by subsequent calls of |
|
552 inflate(). |
|
553 */ |
|
554 |
|
555 /* |
|
556 Skips invalid compressed data until a full flush point (see above the |
|
557 description of deflate with Z_FULL_FLUSH) can be found, or until all |
|
558 available input is skipped. No output is provided. |
|
559 |
|
560 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR |
|
561 if no more input was provided, Z_DATA_ERROR if no flush point has been found, |
|
562 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success |
|
563 case, the application may save the current current value of total_in which |
|
564 indicates where valid compressed data was found. In the error case, the |
|
565 application may repeatedly call inflateSync, providing more input each time, |
|
566 until success or end of the input data. |
|
567 */ |
|
568 |
|
569 ZEXTERN(int) inflateReset OF((z_streamp strm)); |
|
570 /* |
|
571 This function is equivalent to inflateEnd followed by inflateInit, |
|
572 but does not free and reallocate all the internal decompression state. |
|
573 The stream will keep attributes that may have been set by inflateInit2. |
|
574 |
|
575 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
|
576 stream state was inconsistent (such as zalloc or state being NULL). |
|
577 */ |
|
578 |
|
579 |
|
580 /* utility functions */ |
|
581 |
|
582 /* |
|
583 The following utility functions are implemented on top of the |
|
584 basic stream-oriented functions. To simplify the interface, some |
|
585 default options are assumed (compression level and memory usage, |
|
586 standard memory allocation functions). The source code of these |
|
587 utility functions can easily be modified if you need special options. |
|
588 */ |
|
589 |
|
590 /* |
|
591 Compresses the source buffer into the destination buffer. sourceLen is |
|
592 the byte length of the source buffer. Upon entry, destLen is the total |
|
593 size of the destination buffer, which must be at least 0.1% larger than |
|
594 sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the |
|
595 compressed buffer. |
|
596 This function can be used to compress a whole file at once if the |
|
597 input file is mmap'ed. |
|
598 compress returns Z_OK if success, Z_MEM_ERROR if there was not |
|
599 enough memory, Z_BUF_ERROR if there was not enough room in the output |
|
600 buffer. |
|
601 */ |
|
602 |
|
603 /* |
|
604 Compresses the source buffer into the destination buffer. The level |
|
605 parameter has the same meaning as in deflateInit. sourceLen is the byte |
|
606 length of the source buffer. Upon entry, destLen is the total size of the |
|
607 destination buffer, which must be at least 0.1% larger than sourceLen plus |
|
608 12 bytes. Upon exit, destLen is the actual size of the compressed buffer. |
|
609 |
|
610 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
|
611 memory, Z_BUF_ERROR if there was not enough room in the output buffer, |
|
612 Z_STREAM_ERROR if the level parameter is invalid. |
|
613 */ |
|
614 |
|
615 /* |
|
616 Decompresses the source buffer into the destination buffer. sourceLen is |
|
617 the byte length of the source buffer. Upon entry, destLen is the total |
|
618 size of the destination buffer, which must be large enough to hold the |
|
619 entire uncompressed data. (The size of the uncompressed data must have |
|
620 been saved previously by the compressor and transmitted to the decompressor |
|
621 by some mechanism outside the scope of this compression library.) |
|
622 Upon exit, destLen is the actual size of the compressed buffer. |
|
623 This function can be used to decompress a whole file at once if the |
|
624 input file is mmap'ed. |
|
625 |
|
626 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not |
|
627 enough memory, Z_BUF_ERROR if there was not enough room in the output |
|
628 buffer, or Z_DATA_ERROR if the input data was corrupted. |
|
629 */ |
|
630 |
|
631 |
|
632 /* |
|
633 Opens a gzip (.gz) file for reading or writing. The mode parameter |
|
634 is as in fopen ("rb" or "wb") but can also include a compression level |
|
635 ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for |
|
636 Huffman only compression as in "wb1h". (See the description |
|
637 of deflateInit2 for more information about the strategy parameter.) |
|
638 |
|
639 gzopen can be used to read a file which is not in gzip format; in this |
|
640 case gzread will directly read from the file without decompression. |
|
641 |
|
642 gzopen returns NULL if the file could not be opened or if there was |
|
643 insufficient memory to allocate the (de)compression state; errno |
|
644 can be checked to distinguish the two cases (if errno is zero, the |
|
645 zlib error is Z_MEM_ERROR). */ |
|
646 |
|
647 /* |
|
648 gzdopen() associates a gzFile with the file descriptor fd. File |
|
649 descriptors are obtained from calls like open, dup, creat, pipe or |
|
650 fileno (in the file has been previously opened with fopen). |
|
651 The mode parameter is as in gzopen. |
|
652 The next call of gzclose on the returned gzFile will also close the |
|
653 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file |
|
654 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). |
|
655 gzdopen returns NULL if there was insufficient memory to allocate |
|
656 the (de)compression state. |
|
657 */ |
|
658 |
|
659 /* |
|
660 Dynamically update the compression level or strategy. See the description |
|
661 of deflateInit2 for the meaning of these parameters. |
|
662 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not |
|
663 opened for writing. |
|
664 */ |
|
665 |
|
666 /* |
|
667 Reads the given number of uncompressed bytes from the compressed file. |
|
668 If the input file was not in gzip format, gzread copies the given number |
|
669 of bytes into the buffer. |
|
670 gzread returns the number of uncompressed bytes actually read (0 for |
|
671 end of file, -1 for error). */ |
|
672 |
|
673 /* |
|
674 Writes the given number of uncompressed bytes into the compressed file. |
|
675 gzwrite returns the number of uncompressed bytes actually written |
|
676 (0 in case of error). |
|
677 */ |
|
678 |
|
679 /* |
|
680 Converts, formats, and writes the args to the compressed file under |
|
681 control of the format string, as in fprintf. gzprintf returns the number of |
|
682 uncompressed bytes actually written (0 in case of error). |
|
683 */ |
|
684 |
|
685 /* |
|
686 Writes the given null-terminated string to the compressed file, excluding |
|
687 the terminating null character. |
|
688 gzputs returns the number of characters written, or -1 in case of error. |
|
689 */ |
|
690 |
|
691 /* |
|
692 Reads bytes from the compressed file until len-1 characters are read, or |
|
693 a newline character is read and transferred to buf, or an end-of-file |
|
694 condition is encountered. The string is then terminated with a null |
|
695 character. |
|
696 gzgets returns buf, or Z_NULL in case of error. |
|
697 */ |
|
698 |
|
699 /* |
|
700 Writes c, converted to an unsigned char, into the compressed file. |
|
701 gzputc returns the value that was written, or -1 in case of error. |
|
702 */ |
|
703 |
|
704 /* |
|
705 Reads one byte from the compressed file. gzgetc returns this byte |
|
706 or -1 in case of end of file or error. |
|
707 */ |
|
708 |
|
709 /* |
|
710 Flushes all pending output into the compressed file. The parameter |
|
711 flush is as in the deflate() function. The return value is the zlib |
|
712 error number (see function gzerror below). gzflush returns Z_OK if |
|
713 the flush parameter is Z_FINISH and all output could be flushed. |
|
714 gzflush should be called only when strictly necessary because it can |
|
715 degrade compression. |
|
716 */ |
|
717 |
|
718 /* |
|
719 Sets the starting position for the next gzread or gzwrite on the |
|
720 given compressed file. The offset represents a number of bytes in the |
|
721 uncompressed data stream. The whence parameter is defined as in lseek(2); |
|
722 the value SEEK_END is not supported. |
|
723 If the file is opened for reading, this function is emulated but can be |
|
724 extremely slow. If the file is opened for writing, only forward seeks are |
|
725 supported; gzseek then compresses a sequence of zeroes up to the new |
|
726 starting position. |
|
727 |
|
728 gzseek returns the resulting offset location as measured in bytes from |
|
729 the beginning of the uncompressed stream, or -1 in case of error, in |
|
730 particular if the file is opened for writing and the new starting position |
|
731 would be before the current position. |
|
732 */ |
|
733 |
|
734 /* |
|
735 Rewinds the given file. This function is supported only for reading. |
|
736 |
|
737 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) |
|
738 */ |
|
739 |
|
740 /* |
|
741 Returns the starting position for the next gzread or gzwrite on the |
|
742 given compressed file. This position represents a number of bytes in the |
|
743 uncompressed data stream. |
|
744 |
|
745 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) |
|
746 */ |
|
747 |
|
748 /* |
|
749 Returns 1 when EOF has previously been detected reading the given |
|
750 input stream, otherwise zero. |
|
751 */ |
|
752 |
|
753 /* |
|
754 Flushes all pending output if necessary, closes the compressed file |
|
755 and deallocates all the (de)compression state. The return value is the zlib |
|
756 error number (see function gzerror below). |
|
757 */ |
|
758 |
|
759 /* |
|
760 Returns the error message for the last error which occurred on the |
|
761 given compressed file. errnum is set to zlib error number. If an |
|
762 error occurred in the file system and not in the compression library, |
|
763 errnum is set to Z_ERRNO and the application may consult errno |
|
764 to get the exact error code. |
|
765 */ |
|
766 |
|
767 /* checksum functions */ |
|
768 |
|
769 /* |
|
770 These functions are not related to compression but are exported |
|
771 anyway because they might be useful in applications using the |
|
772 compression library. |
|
773 */ |
|
774 |
|
775 ZEXTERN(uLong) adler32 OF((uLong adler, const Bytef *buf, uInt len)); |
|
776 |
|
777 /* |
|
778 Update a running Adler-32 checksum with the bytes buf[0..len-1] and |
|
779 return the updated checksum. If buf is NULL, this function returns |
|
780 the required initial value for the checksum. |
|
781 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed |
|
782 much faster. Usage example: |
|
783 |
|
784 uLong adler = adler32(0L, Z_NULL, 0); |
|
785 |
|
786 while (read_buffer(buffer, length) != EOF) { |
|
787 adler = adler32(adler, buffer, length); |
|
788 } |
|
789 if (adler != original_adler) error(); |
|
790 */ |
|
791 |
|
792 /* |
|
793 Update a running crc with the bytes buf[0..len-1] and return the updated |
|
794 crc. If buf is NULL, this function returns the required initial value |
|
795 for the crc. Pre- and post-conditioning (one's complement) is performed |
|
796 within this function so it shouldn't be done by the application. |
|
797 Usage example: |
|
798 |
|
799 uLong crc = crc32(0L, Z_NULL, 0); |
|
800 |
|
801 while (read_buffer(buffer, length) != EOF) { |
|
802 crc = crc32(crc, buffer, length); |
|
803 } |
|
804 if (crc != original_crc) error(); |
|
805 */ |
|
806 |
|
807 |
|
808 /* various hacks, don't look :) */ |
|
809 |
|
810 /* deflateInit and inflateInit are macros to allow checking the zlib version |
|
811 * and the compiler's view of z_stream: |
|
812 */ |
|
813 ZEXTERN(int) inflateInit2_ OF((z_streamp strm, int windowBits, |
|
814 const char *version, int stream_size)); |
|
815 #define deflateInit(strm, level) \ |
|
816 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) |
|
817 #define inflateInit(strm) \ |
|
818 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) |
|
819 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ |
|
820 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ |
|
821 (strategy), ZLIB_VERSION, sizeof(z_stream)) |
|
822 #define inflateInit2(strm, windowBits) \ |
|
823 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) |
|
824 |
|
825 |
|
826 #ifdef __cplusplus |
|
827 } |
|
828 #endif |
|
829 |
|
830 #endif /* _ZLIB_H */ |
|