1 | /* zlib.h -- interface of the 'zlib' general purpose compression library |
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2 | version 1.2.1, November 17th, 2003 |
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3 | |
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4 | Copyright (C) 1995-2003 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 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 | |
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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 "1.2.1" |
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41 | #define ZLIB_VERNUM 0x1210 |
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42 | |
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43 | /* |
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44 | The 'zlib' compression library provides in-memory compression and |
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45 | decompression functions, including integrity checks of the uncompressed |
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46 | data. This version of the library supports only one compression method |
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47 | (deflation) but other algorithms will be added later and will have the same |
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48 | stream interface. |
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49 | |
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50 | Compression can be done in a single step if the buffers are large |
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51 | enough (for example if an input file is mmap'ed), or can be done by |
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52 | repeated calls of the compression function. In the latter case, the |
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53 | application must provide more input and/or consume the output |
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54 | (providing more output space) before each call. |
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55 | |
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56 | The compressed data format used by the in-memory functions is the zlib |
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57 | format, which is a zlib wrapper documented in RFC 1950, wrapped around a |
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58 | deflate stream, which is itself documented in RFC 1951. |
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59 | |
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60 | The library also supports reading and writing files in gzip (.gz) format |
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61 | with an interface similar to that of stdio using the functions that start |
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62 | with "gz". The gzip format is different from the zlib format. gzip is a |
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63 | gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. |
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64 | |
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65 | The zlib format was designed to be compact and fast for use in memory |
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66 | and on communications channels. The gzip format was designed for single- |
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67 | file compression on file systems, has a larger header than zlib to maintain |
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68 | directory information, and uses a different, slower check method than zlib. |
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69 | |
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70 | This library does not provide any functions to write gzip files in memory. |
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71 | However such functions could be easily written using zlib's deflate function, |
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72 | the documentation in the gzip RFC, and the examples in gzio.c. |
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73 | |
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74 | The library does not install any signal handler. The decoder checks |
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75 | the consistency of the compressed data, so the library should never |
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76 | crash even in case of corrupted input. |
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77 | */ |
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78 | |
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79 | typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); |
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80 | typedef void (*free_func) OF((voidpf opaque, voidpf address)); |
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81 | |
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82 | struct internal_state; |
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83 | |
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84 | typedef struct z_stream_s { |
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85 | Bytef *next_in; /* next input byte */ |
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86 | uInt avail_in; /* number of bytes available at next_in */ |
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87 | uLong total_in; /* total nb of input bytes read so far */ |
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88 | |
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89 | Bytef *next_out; /* next output byte should be put there */ |
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90 | uInt avail_out; /* remaining free space at next_out */ |
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91 | uLong total_out; /* total nb of bytes output so far */ |
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92 | |
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93 | char *msg; /* last error message, NULL if no error */ |
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94 | struct internal_state FAR *state; /* not visible by applications */ |
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95 | |
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96 | alloc_func zalloc; /* used to allocate the internal state */ |
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97 | free_func zfree; /* used to free the internal state */ |
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98 | voidpf opaque; /* private data object passed to zalloc and zfree */ |
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99 | |
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100 | int data_type; /* best guess about the data type: ascii or binary */ |
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101 | uLong adler; /* adler32 value of the uncompressed data */ |
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102 | uLong reserved; /* reserved for future use */ |
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103 | } z_stream; |
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104 | |
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105 | typedef z_stream FAR *z_streamp; |
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106 | |
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107 | /* |
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108 | The application must update next_in and avail_in when avail_in has |
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109 | dropped to zero. It must update next_out and avail_out when avail_out |
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110 | has dropped to zero. The application must initialize zalloc, zfree and |
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111 | opaque before calling the init function. All other fields are set by the |
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112 | compression library and must not be updated by the application. |
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113 | |
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114 | The opaque value provided by the application will be passed as the first |
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115 | parameter for calls of zalloc and zfree. This can be useful for custom |
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116 | memory management. The compression library attaches no meaning to the |
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117 | opaque value. |
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118 | |
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119 | zalloc must return Z_NULL if there is not enough memory for the object. |
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120 | If zlib is used in a multi-threaded application, zalloc and zfree must be |
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121 | thread safe. |
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122 | |
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123 | On 16-bit systems, the functions zalloc and zfree must be able to allocate |
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124 | exactly 65536 bytes, but will not be required to allocate more than this |
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125 | if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, |
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126 | pointers returned by zalloc for objects of exactly 65536 bytes *must* |
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127 | have their offset normalized to zero. The default allocation function |
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128 | provided by this library ensures this (see zutil.c). To reduce memory |
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129 | requirements and avoid any allocation of 64K objects, at the expense of |
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130 | compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). |
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131 | |
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132 | The fields total_in and total_out can be used for statistics or |
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133 | progress reports. After compression, total_in holds the total size of |
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134 | the uncompressed data and may be saved for use in the decompressor |
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135 | (particularly if the decompressor wants to decompress everything in |
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136 | a single step). |
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137 | */ |
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138 | |
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139 | /* constants */ |
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140 | |
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141 | #define Z_NO_FLUSH 0 |
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142 | #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ |
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143 | #define Z_SYNC_FLUSH 2 |
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144 | #define Z_FULL_FLUSH 3 |
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145 | #define Z_FINISH 4 |
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146 | #define Z_BLOCK 5 |
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147 | /* Allowed flush values; see deflate() and inflate() below for details */ |
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148 | |
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149 | #define Z_OK 0 |
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150 | #define Z_STREAM_END 1 |
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151 | #define Z_NEED_DICT 2 |
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152 | #define Z_ERRNO (-1) |
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153 | #define Z_STREAM_ERROR (-2) |
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154 | #define Z_DATA_ERROR (-3) |
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155 | #define Z_MEM_ERROR (-4) |
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156 | #define Z_BUF_ERROR (-5) |
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157 | #define Z_VERSION_ERROR (-6) |
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158 | /* Return codes for the compression/decompression functions. Negative |
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159 | * values are errors, positive values are used for special but normal events. |
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160 | */ |
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161 | |
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162 | #define Z_NO_COMPRESSION 0 |
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163 | #define Z_BEST_SPEED 1 |
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164 | #define Z_BEST_COMPRESSION 9 |
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165 | #define Z_DEFAULT_COMPRESSION (-1) |
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166 | /* compression levels */ |
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167 | |
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168 | #define Z_FILTERED 1 |
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169 | #define Z_HUFFMAN_ONLY 2 |
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170 | #define Z_RLE 3 |
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171 | #define Z_DEFAULT_STRATEGY 0 |
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172 | /* compression strategy; see deflateInit2() below for details */ |
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173 | |
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174 | #define Z_BINARY 0 |
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175 | #define Z_ASCII 1 |
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176 | #define Z_UNKNOWN 2 |
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177 | /* Possible values of the data_type field (though see inflate()) */ |
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178 | |
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179 | #define Z_DEFLATED 8 |
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180 | /* The deflate compression method (the only one supported in this version) */ |
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181 | |
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182 | #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ |
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183 | |
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184 | #define zlib_version zlibVersion() |
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185 | /* for compatibility with versions < 1.0.2 */ |
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186 | |
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187 | /* basic functions */ |
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188 | |
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189 | ZEXTERN const char * ZEXPORT zlibVersion OF((void)); |
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190 | /* The application can compare zlibVersion and ZLIB_VERSION for consistency. |
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191 | If the first character differs, the library code actually used is |
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192 | not compatible with the zlib.h header file used by the application. |
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193 | This check is automatically made by deflateInit and inflateInit. |
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194 | */ |
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195 | |
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196 | /* |
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197 | ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); |
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198 | |
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199 | Initializes the internal stream state for compression. The fields |
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200 | zalloc, zfree and opaque must be initialized before by the caller. |
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201 | If zalloc and zfree are set to Z_NULL, deflateInit updates them to |
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202 | use default allocation functions. |
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203 | |
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204 | The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: |
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205 | 1 gives best speed, 9 gives best compression, 0 gives no compression at |
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206 | all (the input data is simply copied a block at a time). |
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207 | Z_DEFAULT_COMPRESSION requests a default compromise between speed and |
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208 | compression (currently equivalent to level 6). |
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209 | |
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210 | deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not |
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211 | enough memory, Z_STREAM_ERROR if level is not a valid compression level, |
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212 | Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible |
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213 | with the version assumed by the caller (ZLIB_VERSION). |
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214 | msg is set to null if there is no error message. deflateInit does not |
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215 | perform any compression: this will be done by deflate(). |
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216 | */ |
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217 | |
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218 | |
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219 | ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); |
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220 | /* |
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221 | deflate compresses as much data as possible, and stops when the input |
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222 | buffer becomes empty or the output buffer becomes full. It may introduce some |
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223 | output latency (reading input without producing any output) except when |
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224 | forced to flush. |
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225 | |
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226 | The detailed semantics are as follows. deflate performs one or both of the |
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227 | following actions: |
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228 | |
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229 | - Compress more input starting at next_in and update next_in and avail_in |
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230 | accordingly. If not all input can be processed (because there is not |
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231 | enough room in the output buffer), next_in and avail_in are updated and |
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232 | processing will resume at this point for the next call of deflate(). |
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233 | |
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234 | - Provide more output starting at next_out and update next_out and avail_out |
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235 | accordingly. This action is forced if the parameter flush is non zero. |
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236 | Forcing flush frequently degrades the compression ratio, so this parameter |
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237 | should be set only when necessary (in interactive applications). |
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238 | Some output may be provided even if flush is not set. |
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239 | |
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240 | Before the call of deflate(), the application should ensure that at least |
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241 | one of the actions is possible, by providing more input and/or consuming |
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242 | more output, and updating avail_in or avail_out accordingly; avail_out |
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243 | should never be zero before the call. The application can consume the |
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244 | compressed output when it wants, for example when the output buffer is full |
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245 | (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK |
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246 | and with zero avail_out, it must be called again after making room in the |
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247 | output buffer because there might be more output pending. |
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248 | |
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249 | If the parameter flush is set to Z_SYNC_FLUSH, all pending output is |
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250 | flushed to the output buffer and the output is aligned on a byte boundary, so |
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251 | that the decompressor can get all input data available so far. (In particular |
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252 | avail_in is zero after the call if enough output space has been provided |
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253 | before the call.) Flushing may degrade compression for some compression |
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254 | algorithms and so it should be used only when necessary. |
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255 | |
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256 | If flush is set to Z_FULL_FLUSH, all output is flushed as with |
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257 | Z_SYNC_FLUSH, and the compression state is reset so that decompression can |
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258 | restart from this point if previous compressed data has been damaged or if |
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259 | random access is desired. Using Z_FULL_FLUSH too often can seriously degrade |
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260 | the compression. |
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261 | |
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262 | If deflate returns with avail_out == 0, this function must be called again |
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263 | with the same value of the flush parameter and more output space (updated |
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264 | avail_out), until the flush is complete (deflate returns with non-zero |
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265 | avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that |
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266 | avail_out is greater than six to avoid repeated flush markers due to |
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267 | avail_out == 0 on return. |
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268 | |
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269 | If the parameter flush is set to Z_FINISH, pending input is processed, |
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270 | pending output is flushed and deflate returns with Z_STREAM_END if there |
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271 | was enough output space; if deflate returns with Z_OK, this function must be |
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272 | called again with Z_FINISH and more output space (updated avail_out) but no |
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273 | more input data, until it returns with Z_STREAM_END or an error. After |
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274 | deflate has returned Z_STREAM_END, the only possible operations on the |
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275 | stream are deflateReset or deflateEnd. |
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276 | |
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277 | Z_FINISH can be used immediately after deflateInit if all the compression |
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278 | is to be done in a single step. In this case, avail_out must be at least |
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279 | the value returned by deflateBound (see below). If deflate does not return |
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280 | Z_STREAM_END, then it must be called again as described above. |
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281 | |
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282 | deflate() sets strm->adler to the adler32 checksum of all input read |
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283 | so far (that is, total_in bytes). |
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284 | |
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285 | deflate() may update data_type if it can make a good guess about |
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286 | the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered |
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287 | binary. This field is only for information purposes and does not affect |
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288 | the compression algorithm in any manner. |
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289 | |
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290 | deflate() returns Z_OK if some progress has been made (more input |
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291 | processed or more output produced), Z_STREAM_END if all input has been |
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292 | consumed and all output has been produced (only when flush is set to |
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293 | Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example |
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294 | if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible |
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295 | (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not |
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296 | fatal, and deflate() can be called again with more input and more output |
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297 | space to continue compressing. |
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298 | */ |
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299 | |
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300 | |
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301 | ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); |
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302 | /* |
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303 | All dynamically allocated data structures for this stream are freed. |
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304 | This function discards any unprocessed input and does not flush any |
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305 | pending output. |
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306 | |
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307 | deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the |
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308 | stream state was inconsistent, Z_DATA_ERROR if the stream was freed |
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309 | prematurely (some input or output was discarded). In the error case, |
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310 | msg may be set but then points to a static string (which must not be |
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311 | deallocated). |
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312 | */ |
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313 | |
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314 | |
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315 | /* |
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316 | ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); |
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317 | |
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318 | Initializes the internal stream state for decompression. The fields |
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319 | next_in, avail_in, zalloc, zfree and opaque must be initialized before by |
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320 | the caller. If next_in is not Z_NULL and avail_in is large enough (the exact |
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321 | value depends on the compression method), inflateInit determines the |
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322 | compression method from the zlib header and allocates all data structures |
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323 | accordingly; otherwise the allocation will be deferred to the first call of |
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324 | inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to |
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325 | use default allocation functions. |
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326 | |
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327 | inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough |
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328 | memory, Z_VERSION_ERROR if the zlib library version is incompatible with the |
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329 | version assumed by the caller. msg is set to null if there is no error |
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330 | message. inflateInit does not perform any decompression apart from reading |
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331 | the zlib header if present: this will be done by inflate(). (So next_in and |
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332 | avail_in may be modified, but next_out and avail_out are unchanged.) |
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333 | */ |
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334 | |
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335 | |
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336 | ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); |
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337 | /* |
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338 | inflate decompresses as much data as possible, and stops when the input |
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339 | buffer becomes empty or the output buffer becomes full. It may introduce |
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340 | some output latency (reading input without producing any output) except when |
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341 | forced to flush. |
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342 | |
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343 | The detailed semantics are as follows. inflate performs one or both of the |
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344 | following actions: |
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345 | |
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346 | - Decompress more input starting at next_in and update next_in and avail_in |
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347 | accordingly. If not all input can be processed (because there is not |
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348 | enough room in the output buffer), next_in is updated and processing |
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349 | will resume at this point for the next call of inflate(). |
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350 | |
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351 | - Provide more output starting at next_out and update next_out and avail_out |
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352 | accordingly. inflate() provides as much output as possible, until there |
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353 | is no more input data or no more space in the output buffer (see below |
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354 | about the flush parameter). |
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355 | |
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356 | Before the call of inflate(), the application should ensure that at least |
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357 | one of the actions is possible, by providing more input and/or consuming |
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358 | more output, and updating the next_* and avail_* values accordingly. |
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359 | The application can consume the uncompressed output when it wants, for |
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360 | example when the output buffer is full (avail_out == 0), or after each |
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361 | call of inflate(). If inflate returns Z_OK and with zero avail_out, it |
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362 | must be called again after making room in the output buffer because there |
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363 | might be more output pending. |
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364 | |
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365 | The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, |
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366 | Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much |
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367 | output as possible to the output buffer. Z_BLOCK requests that inflate() stop |
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368 | if and when it get to the next deflate block boundary. When decoding the zlib |
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369 | or gzip format, this will cause inflate() to return immediately after the |
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370 | header and before the first block. When doing a raw inflate, inflate() will |
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371 | go ahead and process the first block, and will return when it gets to the end |
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372 | of that block, or when it runs out of data. |
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373 | |
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374 | The Z_BLOCK option assists in appending to or combining deflate streams. |
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375 | Also to assist in this, on return inflate() will set strm->data_type to the |
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376 | number of unused bits in the last byte taken from strm->next_in, plus 64 |
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377 | if inflate() is currently decoding the last block in the deflate stream, |
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378 | plus 128 if inflate() returned immediately after decoding an end-of-block |
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379 | code or decoding the complete header up to just before the first byte of the |
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380 | deflate stream. The end-of-block will not be indicated until all of the |
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381 | uncompressed data from that block has been written to strm->next_out. The |
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382 | number of unused bits may in general be greater than seven, except when |
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383 | bit 7 of data_type is set, in which case the number of unused bits will be |
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384 | less than eight. |
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385 | |
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386 | inflate() should normally be called until it returns Z_STREAM_END or an |
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387 | error. However if all decompression is to be performed in a single step |
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388 | (a single call of inflate), the parameter flush should be set to |
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389 | Z_FINISH. In this case all pending input is processed and all pending |
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390 | output is flushed; avail_out must be large enough to hold all the |
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391 | uncompressed data. (The size of the uncompressed data may have been saved |
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392 | by the compressor for this purpose.) The next operation on this stream must |
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393 | be inflateEnd to deallocate the decompression state. The use of Z_FINISH |
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394 | is never required, but can be used to inform inflate that a faster approach |
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395 | may be used for the single inflate() call. |
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396 | |
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397 | In this implementation, inflate() always flushes as much output as |
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398 | possible to the output buffer, and always uses the faster approach on the |
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399 | first call. So the only effect of the flush parameter in this implementation |
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400 | is on the return value of inflate(), as noted below, or when it returns early |
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401 | because Z_BLOCK is used. |
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402 | |
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403 | If a preset dictionary is needed after this call (see inflateSetDictionary |
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404 | below), inflate sets strm-adler to the adler32 checksum of the dictionary |
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405 | chosen by the compressor and returns Z_NEED_DICT; otherwise it sets |
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406 | strm->adler to the adler32 checksum of all output produced so far (that is, |
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407 | total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described |
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408 | below. At the end of the stream, inflate() checks that its computed adler32 |
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409 | checksum is equal to that saved by the compressor and returns Z_STREAM_END |
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410 | only if the checksum is correct. |
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411 | |
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412 | inflate() will decompress and check either zlib-wrapped or gzip-wrapped |
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413 | deflate data. The header type is detected automatically. Any information |
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414 | contained in the gzip header is not retained, so applications that need that |
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415 | information should instead use raw inflate, see inflateInit2() below, or |
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416 | inflateBack() and perform their own processing of the gzip header and |
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417 | trailer. |
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418 | |
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419 | inflate() returns Z_OK if some progress has been made (more input processed |
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420 | or more output produced), Z_STREAM_END if the end of the compressed data has |
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421 | been reached and all uncompressed output has been produced, Z_NEED_DICT if a |
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422 | preset dictionary is needed at this point, Z_DATA_ERROR if the input data was |
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423 | corrupted (input stream not conforming to the zlib format or incorrect check |
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424 | value), Z_STREAM_ERROR if the stream structure was inconsistent (for example |
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425 | if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory, |
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426 | Z_BUF_ERROR if no progress is possible or if there was not enough room in the |
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427 | output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and |
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428 | inflate() can be called again with more input and more output space to |
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429 | continue decompressing. If Z_DATA_ERROR is returned, the application may then |
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430 | call inflateSync() to look for a good compression block if a partial recovery |
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431 | of the data is desired. |
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432 | */ |
---|
433 | |
---|
434 | |
---|
435 | ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); |
---|
436 | /* |
---|
437 | All dynamically allocated data structures for this stream are freed. |
---|
438 | This function discards any unprocessed input and does not flush any |
---|
439 | pending output. |
---|
440 | |
---|
441 | inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state |
---|
442 | was inconsistent. In the error case, msg may be set but then points to a |
---|
443 | static string (which must not be deallocated). |
---|
444 | */ |
---|
445 | |
---|
446 | /* Advanced functions */ |
---|
447 | |
---|
448 | /* |
---|
449 | The following functions are needed only in some special applications. |
---|
450 | */ |
---|
451 | |
---|
452 | /* |
---|
453 | ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, |
---|
454 | int level, |
---|
455 | int method, |
---|
456 | int windowBits, |
---|
457 | int memLevel, |
---|
458 | int strategy)); |
---|
459 | |
---|
460 | This is another version of deflateInit with more compression options. The |
---|
461 | fields next_in, zalloc, zfree and opaque must be initialized before by |
---|
462 | the caller. |
---|
463 | |
---|
464 | The method parameter is the compression method. It must be Z_DEFLATED in |
---|
465 | this version of the library. |
---|
466 | |
---|
467 | The windowBits parameter is the base two logarithm of the window size |
---|
468 | (the size of the history buffer). It should be in the range 8..15 for this |
---|
469 | version of the library. Larger values of this parameter result in better |
---|
470 | compression at the expense of memory usage. The default value is 15 if |
---|
471 | deflateInit is used instead. |
---|
472 | |
---|
473 | windowBits can also be -8..-15 for raw deflate. In this case, -windowBits |
---|
474 | determines the window size. deflate() will then generate raw deflate data |
---|
475 | with no zlib header or trailer, and will not compute an adler32 check value. |
---|
476 | |
---|
477 | windowBits can also be greater than 15 for optional gzip encoding. Add |
---|
478 | 16 to windowBits to write a simple gzip header and trailer around the |
---|
479 | compressed data instead of a zlib wrapper. The gzip header will have no |
---|
480 | file name, no extra data, no comment, no modification time (set to zero), |
---|
481 | no header crc, and the operating system will be set to 255 (unknown). |
---|
482 | |
---|
483 | The memLevel parameter specifies how much memory should be allocated |
---|
484 | for the internal compression state. memLevel=1 uses minimum memory but |
---|
485 | is slow and reduces compression ratio; memLevel=9 uses maximum memory |
---|
486 | for optimal speed. The default value is 8. See zconf.h for total memory |
---|
487 | usage as a function of windowBits and memLevel. |
---|
488 | |
---|
489 | The strategy parameter is used to tune the compression algorithm. Use the |
---|
490 | value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a |
---|
491 | filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no |
---|
492 | string match), or Z_RLE to limit match distances to one (run-length |
---|
493 | encoding). Filtered data consists mostly of small values with a somewhat |
---|
494 | random distribution. In this case, the compression algorithm is tuned to |
---|
495 | compress them better. The effect of Z_FILTERED is to force more Huffman |
---|
496 | coding and less string matching; it is somewhat intermediate between |
---|
497 | Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as |
---|
498 | Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy |
---|
499 | parameter only affects the compression ratio but not the correctness of the |
---|
500 | compressed output even if it is not set appropriately. |
---|
501 | |
---|
502 | deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
---|
503 | memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid |
---|
504 | method). msg is set to null if there is no error message. deflateInit2 does |
---|
505 | not perform any compression: this will be done by deflate(). |
---|
506 | */ |
---|
507 | |
---|
508 | ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, |
---|
509 | const Bytef *dictionary, |
---|
510 | uInt dictLength)); |
---|
511 | /* |
---|
512 | Initializes the compression dictionary from the given byte sequence |
---|
513 | without producing any compressed output. This function must be called |
---|
514 | immediately after deflateInit, deflateInit2 or deflateReset, before any |
---|
515 | call of deflate. The compressor and decompressor must use exactly the same |
---|
516 | dictionary (see inflateSetDictionary). |
---|
517 | |
---|
518 | The dictionary should consist of strings (byte sequences) that are likely |
---|
519 | to be encountered later in the data to be compressed, with the most commonly |
---|
520 | used strings preferably put towards the end of the dictionary. Using a |
---|
521 | dictionary is most useful when the data to be compressed is short and can be |
---|
522 | predicted with good accuracy; the data can then be compressed better than |
---|
523 | with the default empty dictionary. |
---|
524 | |
---|
525 | Depending on the size of the compression data structures selected by |
---|
526 | deflateInit or deflateInit2, a part of the dictionary may in effect be |
---|
527 | discarded, for example if the dictionary is larger than the window size in |
---|
528 | deflate or deflate2. Thus the strings most likely to be useful should be |
---|
529 | put at the end of the dictionary, not at the front. |
---|
530 | |
---|
531 | Upon return of this function, strm->adler is set to the adler32 value |
---|
532 | of the dictionary; the decompressor may later use this value to determine |
---|
533 | which dictionary has been used by the compressor. (The adler32 value |
---|
534 | applies to the whole dictionary even if only a subset of the dictionary is |
---|
535 | actually used by the compressor.) If a raw deflate was requested, then the |
---|
536 | adler32 value is not computed and strm->adler is not set. |
---|
537 | |
---|
538 | deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a |
---|
539 | parameter is invalid (such as NULL dictionary) or the stream state is |
---|
540 | inconsistent (for example if deflate has already been called for this stream |
---|
541 | or if the compression method is bsort). deflateSetDictionary does not |
---|
542 | perform any compression: this will be done by deflate(). |
---|
543 | */ |
---|
544 | |
---|
545 | ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, |
---|
546 | z_streamp source)); |
---|
547 | /* |
---|
548 | Sets the destination stream as a complete copy of the source stream. |
---|
549 | |
---|
550 | This function can be useful when several compression strategies will be |
---|
551 | tried, for example when there are several ways of pre-processing the input |
---|
552 | data with a filter. The streams that will be discarded should then be freed |
---|
553 | by calling deflateEnd. Note that deflateCopy duplicates the internal |
---|
554 | compression state which can be quite large, so this strategy is slow and |
---|
555 | can consume lots of memory. |
---|
556 | |
---|
557 | deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
---|
558 | enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
---|
559 | (such as zalloc being NULL). msg is left unchanged in both source and |
---|
560 | destination. |
---|
561 | */ |
---|
562 | |
---|
563 | ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); |
---|
564 | /* |
---|
565 | This function is equivalent to deflateEnd followed by deflateInit, |
---|
566 | but does not free and reallocate all the internal compression state. |
---|
567 | The stream will keep the same compression level and any other attributes |
---|
568 | that may have been set by deflateInit2. |
---|
569 | |
---|
570 | deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
---|
571 | stream state was inconsistent (such as zalloc or state being NULL). |
---|
572 | */ |
---|
573 | |
---|
574 | ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, |
---|
575 | int level, |
---|
576 | int strategy)); |
---|
577 | /* |
---|
578 | Dynamically update the compression level and compression strategy. The |
---|
579 | interpretation of level and strategy is as in deflateInit2. This can be |
---|
580 | used to switch between compression and straight copy of the input data, or |
---|
581 | to switch to a different kind of input data requiring a different |
---|
582 | strategy. If the compression level is changed, the input available so far |
---|
583 | is compressed with the old level (and may be flushed); the new level will |
---|
584 | take effect only at the next call of deflate(). |
---|
585 | |
---|
586 | Before the call of deflateParams, the stream state must be set as for |
---|
587 | a call of deflate(), since the currently available input may have to |
---|
588 | be compressed and flushed. In particular, strm->avail_out must be non-zero. |
---|
589 | |
---|
590 | deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source |
---|
591 | stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR |
---|
592 | if strm->avail_out was zero. |
---|
593 | */ |
---|
594 | |
---|
595 | ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, |
---|
596 | uLong sourceLen)); |
---|
597 | /* |
---|
598 | deflateBound() returns an upper bound on the compressed size after |
---|
599 | deflation of sourceLen bytes. It must be called after deflateInit() |
---|
600 | or deflateInit2(). This would be used to allocate an output buffer |
---|
601 | for deflation in a single pass, and so would be called before deflate(). |
---|
602 | */ |
---|
603 | |
---|
604 | ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, |
---|
605 | int bits, |
---|
606 | int value)); |
---|
607 | /* |
---|
608 | deflatePrime() inserts bits in the deflate output stream. The intent |
---|
609 | is that this function is used to start off the deflate output with the |
---|
610 | bits leftover from a previous deflate stream when appending to it. As such, |
---|
611 | this function can only be used for raw deflate, and must be used before the |
---|
612 | first deflate() call after a deflateInit2() or deflateReset(). bits must be |
---|
613 | less than or equal to 16, and that many of the least significant bits of |
---|
614 | value will be inserted in the output. |
---|
615 | |
---|
616 | deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source |
---|
617 | stream state was inconsistent. |
---|
618 | */ |
---|
619 | |
---|
620 | /* |
---|
621 | ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, |
---|
622 | int windowBits)); |
---|
623 | |
---|
624 | This is another version of inflateInit with an extra parameter. The |
---|
625 | fields next_in, avail_in, zalloc, zfree and opaque must be initialized |
---|
626 | before by the caller. |
---|
627 | |
---|
628 | The windowBits parameter is the base two logarithm of the maximum window |
---|
629 | size (the size of the history buffer). It should be in the range 8..15 for |
---|
630 | this version of the library. The default value is 15 if inflateInit is used |
---|
631 | instead. windowBits must be greater than or equal to the windowBits value |
---|
632 | provided to deflateInit2() while compressing, or it must be equal to 15 if |
---|
633 | deflateInit2() was not used. If a compressed stream with a larger window |
---|
634 | size is given as input, inflate() will return with the error code |
---|
635 | Z_DATA_ERROR instead of trying to allocate a larger window. |
---|
636 | |
---|
637 | windowBits can also be -8..-15 for raw inflate. In this case, -windowBits |
---|
638 | determines the window size. inflate() will then process raw deflate data, |
---|
639 | not looking for a zlib or gzip header, not generating a check value, and not |
---|
640 | looking for any check values for comparison at the end of the stream. This |
---|
641 | is for use with other formats that use the deflate compressed data format |
---|
642 | such as zip. Those formats provide their own check values. If a custom |
---|
643 | format is developed using the raw deflate format for compressed data, it is |
---|
644 | recommended that a check value such as an adler32 or a crc32 be applied to |
---|
645 | the uncompressed data as is done in the zlib, gzip, and zip formats. For |
---|
646 | most applications, the zlib format should be used as is. Note that comments |
---|
647 | above on the use in deflateInit2() applies to the magnitude of windowBits. |
---|
648 | |
---|
649 | windowBits can also be greater than 15 for optional gzip decoding. Add |
---|
650 | 32 to windowBits to enable zlib and gzip decoding with automatic header |
---|
651 | detection, or add 16 to decode only the gzip format (the zlib format will |
---|
652 | return a Z_DATA_ERROR). |
---|
653 | |
---|
654 | inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
---|
655 | memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative |
---|
656 | memLevel). msg is set to null if there is no error message. inflateInit2 |
---|
657 | does not perform any decompression apart from reading the zlib header if |
---|
658 | present: this will be done by inflate(). (So next_in and avail_in may be |
---|
659 | modified, but next_out and avail_out are unchanged.) |
---|
660 | */ |
---|
661 | |
---|
662 | ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, |
---|
663 | const Bytef *dictionary, |
---|
664 | uInt dictLength)); |
---|
665 | /* |
---|
666 | Initializes the decompression dictionary from the given uncompressed byte |
---|
667 | sequence. This function must be called immediately after a call of inflate |
---|
668 | if this call returned Z_NEED_DICT. The dictionary chosen by the compressor |
---|
669 | can be determined from the adler32 value returned by this call of |
---|
670 | inflate. The compressor and decompressor must use exactly the same |
---|
671 | dictionary (see deflateSetDictionary). |
---|
672 | |
---|
673 | inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a |
---|
674 | parameter is invalid (such as NULL dictionary) or the stream state is |
---|
675 | inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the |
---|
676 | expected one (incorrect adler32 value). inflateSetDictionary does not |
---|
677 | perform any decompression: this will be done by subsequent calls of |
---|
678 | inflate(). |
---|
679 | */ |
---|
680 | |
---|
681 | ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); |
---|
682 | /* |
---|
683 | Skips invalid compressed data until a full flush point (see above the |
---|
684 | description of deflate with Z_FULL_FLUSH) can be found, or until all |
---|
685 | available input is skipped. No output is provided. |
---|
686 | |
---|
687 | inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR |
---|
688 | if no more input was provided, Z_DATA_ERROR if no flush point has been found, |
---|
689 | or Z_STREAM_ERROR if the stream structure was inconsistent. In the success |
---|
690 | case, the application may save the current current value of total_in which |
---|
691 | indicates where valid compressed data was found. In the error case, the |
---|
692 | application may repeatedly call inflateSync, providing more input each time, |
---|
693 | until success or end of the input data. |
---|
694 | */ |
---|
695 | |
---|
696 | ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, |
---|
697 | z_streamp source)); |
---|
698 | /* |
---|
699 | Sets the destination stream as a complete copy of the source stream. |
---|
700 | |
---|
701 | This function can be useful when randomly accessing a large stream. The |
---|
702 | first pass through the stream can periodically record the inflate state, |
---|
703 | allowing restarting inflate at those points when randomly accessing the |
---|
704 | stream. |
---|
705 | |
---|
706 | inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
---|
707 | enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
---|
708 | (such as zalloc being NULL). msg is left unchanged in both source and |
---|
709 | destination. |
---|
710 | */ |
---|
711 | |
---|
712 | ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); |
---|
713 | /* |
---|
714 | This function is equivalent to inflateEnd followed by inflateInit, |
---|
715 | but does not free and reallocate all the internal decompression state. |
---|
716 | The stream will keep attributes that may have been set by inflateInit2. |
---|
717 | |
---|
718 | inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
---|
719 | stream state was inconsistent (such as zalloc or state being NULL). |
---|
720 | */ |
---|
721 | |
---|
722 | /* |
---|
723 | ZEXTERN int ZEXPORT inflateBackInit OF((z_stream FAR *strm, int windowBits, |
---|
724 | unsigned char FAR *window)); |
---|
725 | |
---|
726 | Initialize the internal stream state for decompression using inflateBack() |
---|
727 | calls. The fields zalloc, zfree and opaque in strm must be initialized |
---|
728 | before the call. If zalloc and zfree are Z_NULL, then the default library- |
---|
729 | derived memory allocation routines are used. windowBits is the base two |
---|
730 | logarithm of the window size, in the range 8..15. window is a caller |
---|
731 | supplied buffer of that size. Except for special applications where it is |
---|
732 | assured that deflate was used with small window sizes, windowBits must be 15 |
---|
733 | and a 32K byte window must be supplied to be able to decompress general |
---|
734 | deflate streams. |
---|
735 | |
---|
736 | See inflateBack() for the usage of these routines. |
---|
737 | |
---|
738 | inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of |
---|
739 | the paramaters are invalid, Z_MEM_ERROR if the internal state could not |
---|
740 | be allocated, or Z_VERSION_ERROR if the version of the library does not |
---|
741 | match the version of the header file. |
---|
742 | */ |
---|
743 | |
---|
744 | typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *)); |
---|
745 | typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); |
---|
746 | |
---|
747 | ZEXTERN int ZEXPORT inflateBack OF((z_stream FAR *strm, |
---|
748 | in_func in, void FAR *in_desc, |
---|
749 | out_func out, void FAR *out_desc)); |
---|
750 | /* |
---|
751 | inflateBack() does a raw inflate with a single call using a call-back |
---|
752 | interface for input and output. This is more efficient than inflate() for |
---|
753 | file i/o applications in that it avoids copying between the output and the |
---|
754 | sliding window by simply making the window itself the output buffer. This |
---|
755 | function trusts the application to not change the output buffer passed by |
---|
756 | the output function, at least until inflateBack() returns. |
---|
757 | |
---|
758 | inflateBackInit() must be called first to allocate the internal state |
---|
759 | and to initialize the state with the user-provided window buffer. |
---|
760 | inflateBack() may then be used multiple times to inflate a complete, raw |
---|
761 | deflate stream with each call. inflateBackEnd() is then called to free |
---|
762 | the allocated state. |
---|
763 | |
---|
764 | A raw deflate stream is one with no zlib or gzip header or trailer. |
---|
765 | This routine would normally be used in a utility that reads zip or gzip |
---|
766 | files and writes out uncompressed files. The utility would decode the |
---|
767 | header and process the trailer on its own, hence this routine expects |
---|
768 | only the raw deflate stream to decompress. This is different from the |
---|
769 | normal behavior of inflate(), which expects either a zlib or gzip header and |
---|
770 | trailer around the deflate stream. |
---|
771 | |
---|
772 | inflateBack() uses two subroutines supplied by the caller that are then |
---|
773 | called by inflateBack() for input and output. inflateBack() calls those |
---|
774 | routines until it reads a complete deflate stream and writes out all of the |
---|
775 | uncompressed data, or until it encounters an error. The function's |
---|
776 | parameters and return types are defined above in the in_func and out_func |
---|
777 | typedefs. inflateBack() will call in(in_desc, &buf) which should return the |
---|
778 | number of bytes of provided input, and a pointer to that input in buf. If |
---|
779 | there is no input available, in() must return zero--buf is ignored in that |
---|
780 | case--and inflateBack() will return a buffer error. inflateBack() will call |
---|
781 | out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() |
---|
782 | should return zero on success, or non-zero on failure. If out() returns |
---|
783 | non-zero, inflateBack() will return with an error. Neither in() nor out() |
---|
784 | are permitted to change the contents of the window provided to |
---|
785 | inflateBackInit(), which is also the buffer that out() uses to write from. |
---|
786 | The length written by out() will be at most the window size. Any non-zero |
---|
787 | amount of input may be provided by in(). |
---|
788 | |
---|
789 | For convenience, inflateBack() can be provided input on the first call by |
---|
790 | setting strm->next_in and strm->avail_in. If that input is exhausted, then |
---|
791 | in() will be called. Therefore strm->next_in must be initialized before |
---|
792 | calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called |
---|
793 | immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in |
---|
794 | must also be initialized, and then if strm->avail_in is not zero, input will |
---|
795 | initially be taken from strm->next_in[0 .. strm->avail_in - 1]. |
---|
796 | |
---|
797 | The in_desc and out_desc parameters of inflateBack() is passed as the |
---|
798 | first parameter of in() and out() respectively when they are called. These |
---|
799 | descriptors can be optionally used to pass any information that the caller- |
---|
800 | supplied in() and out() functions need to do their job. |
---|
801 | |
---|
802 | On return, inflateBack() will set strm->next_in and strm->avail_in to |
---|
803 | pass back any unused input that was provided by the last in() call. The |
---|
804 | return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR |
---|
805 | if in() or out() returned an error, Z_DATA_ERROR if there was a format |
---|
806 | error in the deflate stream (in which case strm->msg is set to indicate the |
---|
807 | nature of the error), or Z_STREAM_ERROR if the stream was not properly |
---|
808 | initialized. In the case of Z_BUF_ERROR, an input or output error can be |
---|
809 | distinguished using strm->next_in which will be Z_NULL only if in() returned |
---|
810 | an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to |
---|
811 | out() returning non-zero. (in() will always be called before out(), so |
---|
812 | strm->next_in is assured to be defined if out() returns non-zero.) Note |
---|
813 | that inflateBack() cannot return Z_OK. |
---|
814 | */ |
---|
815 | |
---|
816 | ZEXTERN int ZEXPORT inflateBackEnd OF((z_stream FAR *strm)); |
---|
817 | /* |
---|
818 | All memory allocated by inflateBackInit() is freed. |
---|
819 | |
---|
820 | inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream |
---|
821 | state was inconsistent. |
---|
822 | */ |
---|
823 | |
---|
824 | ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); |
---|
825 | /* Return flags indicating compile-time options. |
---|
826 | |
---|
827 | Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: |
---|
828 | 1.0: size of uInt |
---|
829 | 3.2: size of uLong |
---|
830 | 5.4: size of voidpf (pointer) |
---|
831 | 7.6: size of z_off_t |
---|
832 | |
---|
833 | Compiler, assembler, and debug options: |
---|
834 | 8: DEBUG |
---|
835 | 9: ASMV or ASMINF -- use ASM code |
---|
836 | 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention |
---|
837 | 11: 0 (reserved) |
---|
838 | |
---|
839 | One-time table building (smaller code, but not thread-safe if true): |
---|
840 | 12: BUILDFIXED -- build static block decoding tables when needed |
---|
841 | 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed |
---|
842 | 14,15: 0 (reserved) |
---|
843 | |
---|
844 | Library content (indicates missing functionality): |
---|
845 | 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking |
---|
846 | deflate code when not needed) |
---|
847 | 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect |
---|
848 | and decode gzip streams (to avoid linking crc code) |
---|
849 | 18-19: 0 (reserved) |
---|
850 | |
---|
851 | Operation variations (changes in library functionality): |
---|
852 | 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate |
---|
853 | 21: FASTEST -- deflate algorithm with only one, lowest compression level |
---|
854 | 22,23: 0 (reserved) |
---|
855 | |
---|
856 | The sprintf variant used by gzprintf (zero is best): |
---|
857 | 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format |
---|
858 | 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! |
---|
859 | 26: 0 = returns value, 1 = void -- 1 means inferred string length returned |
---|
860 | |
---|
861 | Remainder: |
---|
862 | 27-31: 0 (reserved) |
---|
863 | */ |
---|
864 | |
---|
865 | |
---|
866 | /* utility functions */ |
---|
867 | |
---|
868 | /* |
---|
869 | The following utility functions are implemented on top of the |
---|
870 | basic stream-oriented functions. To simplify the interface, some |
---|
871 | default options are assumed (compression level and memory usage, |
---|
872 | standard memory allocation functions). The source code of these |
---|
873 | utility functions can easily be modified if you need special options. |
---|
874 | */ |
---|
875 | |
---|
876 | ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, |
---|
877 | const Bytef *source, uLong sourceLen)); |
---|
878 | /* |
---|
879 | Compresses the source buffer into the destination buffer. sourceLen is |
---|
880 | the byte length of the source buffer. Upon entry, destLen is the total |
---|
881 | size of the destination buffer, which must be at least the value returned |
---|
882 | by compressBound(sourceLen). Upon exit, destLen is the actual size of the |
---|
883 | compressed buffer. |
---|
884 | This function can be used to compress a whole file at once if the |
---|
885 | input file is mmap'ed. |
---|
886 | compress returns Z_OK if success, Z_MEM_ERROR if there was not |
---|
887 | enough memory, Z_BUF_ERROR if there was not enough room in the output |
---|
888 | buffer. |
---|
889 | */ |
---|
890 | |
---|
891 | ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, |
---|
892 | const Bytef *source, uLong sourceLen, |
---|
893 | int level)); |
---|
894 | /* |
---|
895 | Compresses the source buffer into the destination buffer. The level |
---|
896 | parameter has the same meaning as in deflateInit. sourceLen is the byte |
---|
897 | length of the source buffer. Upon entry, destLen is the total size of the |
---|
898 | destination buffer, which must be at least the value returned by |
---|
899 | compressBound(sourceLen). Upon exit, destLen is the actual size of the |
---|
900 | compressed buffer. |
---|
901 | |
---|
902 | compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
---|
903 | memory, Z_BUF_ERROR if there was not enough room in the output buffer, |
---|
904 | Z_STREAM_ERROR if the level parameter is invalid. |
---|
905 | */ |
---|
906 | |
---|
907 | ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); |
---|
908 | /* |
---|
909 | compressBound() returns an upper bound on the compressed size after |
---|
910 | compress() or compress2() on sourceLen bytes. It would be used before |
---|
911 | a compress() or compress2() call to allocate the destination buffer. |
---|
912 | */ |
---|
913 | |
---|
914 | ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, |
---|
915 | const Bytef *source, uLong sourceLen)); |
---|
916 | /* |
---|
917 | Decompresses the source buffer into the destination buffer. sourceLen is |
---|
918 | the byte length of the source buffer. Upon entry, destLen is the total |
---|
919 | size of the destination buffer, which must be large enough to hold the |
---|
920 | entire uncompressed data. (The size of the uncompressed data must have |
---|
921 | been saved previously by the compressor and transmitted to the decompressor |
---|
922 | by some mechanism outside the scope of this compression library.) |
---|
923 | Upon exit, destLen is the actual size of the compressed buffer. |
---|
924 | This function can be used to decompress a whole file at once if the |
---|
925 | input file is mmap'ed. |
---|
926 | |
---|
927 | uncompress returns Z_OK if success, Z_MEM_ERROR if there was not |
---|
928 | enough memory, Z_BUF_ERROR if there was not enough room in the output |
---|
929 | buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. |
---|
930 | */ |
---|
931 | |
---|
932 | |
---|
933 | typedef voidp gzFile; |
---|
934 | |
---|
935 | ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); |
---|
936 | /* |
---|
937 | Opens a gzip (.gz) file for reading or writing. The mode parameter |
---|
938 | is as in fopen ("rb" or "wb") but can also include a compression level |
---|
939 | ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for |
---|
940 | Huffman only compression as in "wb1h", or 'R' for run-length encoding |
---|
941 | as in "wb1R". (See the description of deflateInit2 for more information |
---|
942 | about the strategy parameter.) |
---|
943 | |
---|
944 | gzopen can be used to read a file which is not in gzip format; in this |
---|
945 | case gzread will directly read from the file without decompression. |
---|
946 | |
---|
947 | gzopen returns NULL if the file could not be opened or if there was |
---|
948 | insufficient memory to allocate the (de)compression state; errno |
---|
949 | can be checked to distinguish the two cases (if errno is zero, the |
---|
950 | zlib error is Z_MEM_ERROR). */ |
---|
951 | |
---|
952 | ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); |
---|
953 | /* |
---|
954 | gzdopen() associates a gzFile with the file descriptor fd. File |
---|
955 | descriptors are obtained from calls like open, dup, creat, pipe or |
---|
956 | fileno (in the file has been previously opened with fopen). |
---|
957 | The mode parameter is as in gzopen. |
---|
958 | The next call of gzclose on the returned gzFile will also close the |
---|
959 | file descriptor fd, just like fclose(fdopen(fd), mode) closes the file |
---|
960 | descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). |
---|
961 | gzdopen returns NULL if there was insufficient memory to allocate |
---|
962 | the (de)compression state. |
---|
963 | */ |
---|
964 | |
---|
965 | ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); |
---|
966 | /* |
---|
967 | Dynamically update the compression level or strategy. See the description |
---|
968 | of deflateInit2 for the meaning of these parameters. |
---|
969 | gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not |
---|
970 | opened for writing. |
---|
971 | */ |
---|
972 | |
---|
973 | ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); |
---|
974 | /* |
---|
975 | Reads the given number of uncompressed bytes from the compressed file. |
---|
976 | If the input file was not in gzip format, gzread copies the given number |
---|
977 | of bytes into the buffer. |
---|
978 | gzread returns the number of uncompressed bytes actually read (0 for |
---|
979 | end of file, -1 for error). */ |
---|
980 | |
---|
981 | ZEXTERN int ZEXPORT gzwrite OF((gzFile file, |
---|
982 | voidpc buf, unsigned len)); |
---|
983 | /* |
---|
984 | Writes the given number of uncompressed bytes into the compressed file. |
---|
985 | gzwrite returns the number of uncompressed bytes actually written |
---|
986 | (0 in case of error). |
---|
987 | */ |
---|
988 | |
---|
989 | ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); |
---|
990 | /* |
---|
991 | Converts, formats, and writes the args to the compressed file under |
---|
992 | control of the format string, as in fprintf. gzprintf returns the number of |
---|
993 | uncompressed bytes actually written (0 in case of error). The number of |
---|
994 | uncompressed bytes written is limited to 4095. The caller should assure that |
---|
995 | this limit is not exceeded. If it is exceeded, then gzprintf() will return |
---|
996 | return an error (0) with nothing written. In this case, there may also be a |
---|
997 | buffer overflow with unpredictable consequences, which is possible only if |
---|
998 | zlib was compiled with the insecure functions sprintf() or vsprintf() |
---|
999 | because the secure snprintf() or vsnprintf() functions were not available. |
---|
1000 | */ |
---|
1001 | |
---|
1002 | ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); |
---|
1003 | /* |
---|
1004 | Writes the given null-terminated string to the compressed file, excluding |
---|
1005 | the terminating null character. |
---|
1006 | gzputs returns the number of characters written, or -1 in case of error. |
---|
1007 | */ |
---|
1008 | |
---|
1009 | ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); |
---|
1010 | /* |
---|
1011 | Reads bytes from the compressed file until len-1 characters are read, or |
---|
1012 | a newline character is read and transferred to buf, or an end-of-file |
---|
1013 | condition is encountered. The string is then terminated with a null |
---|
1014 | character. |
---|
1015 | gzgets returns buf, or Z_NULL in case of error. |
---|
1016 | */ |
---|
1017 | |
---|
1018 | ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); |
---|
1019 | /* |
---|
1020 | Writes c, converted to an unsigned char, into the compressed file. |
---|
1021 | gzputc returns the value that was written, or -1 in case of error. |
---|
1022 | */ |
---|
1023 | |
---|
1024 | ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); |
---|
1025 | /* |
---|
1026 | Reads one byte from the compressed file. gzgetc returns this byte |
---|
1027 | or -1 in case of end of file or error. |
---|
1028 | */ |
---|
1029 | |
---|
1030 | ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); |
---|
1031 | /* |
---|
1032 | Push one character back onto the stream to be read again later. |
---|
1033 | Only one character of push-back is allowed. gzungetc() returns the |
---|
1034 | character pushed, or -1 on failure. gzungetc() will fail if a |
---|
1035 | character has been pushed but not read yet, or if c is -1. The pushed |
---|
1036 | character will be discarded if the stream is repositioned with gzseek() |
---|
1037 | or gzrewind(). |
---|
1038 | */ |
---|
1039 | |
---|
1040 | ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); |
---|
1041 | /* |
---|
1042 | Flushes all pending output into the compressed file. The parameter |
---|
1043 | flush is as in the deflate() function. The return value is the zlib |
---|
1044 | error number (see function gzerror below). gzflush returns Z_OK if |
---|
1045 | the flush parameter is Z_FINISH and all output could be flushed. |
---|
1046 | gzflush should be called only when strictly necessary because it can |
---|
1047 | degrade compression. |
---|
1048 | */ |
---|
1049 | |
---|
1050 | ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, |
---|
1051 | z_off_t offset, int whence)); |
---|
1052 | /* |
---|
1053 | Sets the starting position for the next gzread or gzwrite on the |
---|
1054 | given compressed file. The offset represents a number of bytes in the |
---|
1055 | uncompressed data stream. The whence parameter is defined as in lseek(2); |
---|
1056 | the value SEEK_END is not supported. |
---|
1057 | If the file is opened for reading, this function is emulated but can be |
---|
1058 | extremely slow. If the file is opened for writing, only forward seeks are |
---|
1059 | supported; gzseek then compresses a sequence of zeroes up to the new |
---|
1060 | starting position. |
---|
1061 | |
---|
1062 | gzseek returns the resulting offset location as measured in bytes from |
---|
1063 | the beginning of the uncompressed stream, or -1 in case of error, in |
---|
1064 | particular if the file is opened for writing and the new starting position |
---|
1065 | would be before the current position. |
---|
1066 | */ |
---|
1067 | |
---|
1068 | ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); |
---|
1069 | /* |
---|
1070 | Rewinds the given file. This function is supported only for reading. |
---|
1071 | |
---|
1072 | gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) |
---|
1073 | */ |
---|
1074 | |
---|
1075 | ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); |
---|
1076 | /* |
---|
1077 | Returns the starting position for the next gzread or gzwrite on the |
---|
1078 | given compressed file. This position represents a number of bytes in the |
---|
1079 | uncompressed data stream. |
---|
1080 | |
---|
1081 | gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) |
---|
1082 | */ |
---|
1083 | |
---|
1084 | ZEXTERN int ZEXPORT gzeof OF((gzFile file)); |
---|
1085 | /* |
---|
1086 | Returns 1 when EOF has previously been detected reading the given |
---|
1087 | input stream, otherwise zero. |
---|
1088 | */ |
---|
1089 | |
---|
1090 | ZEXTERN int ZEXPORT gzclose OF((gzFile file)); |
---|
1091 | /* |
---|
1092 | Flushes all pending output if necessary, closes the compressed file |
---|
1093 | and deallocates all the (de)compression state. The return value is the zlib |
---|
1094 | error number (see function gzerror below). |
---|
1095 | */ |
---|
1096 | |
---|
1097 | ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); |
---|
1098 | /* |
---|
1099 | Returns the error message for the last error which occurred on the |
---|
1100 | given compressed file. errnum is set to zlib error number. If an |
---|
1101 | error occurred in the file system and not in the compression library, |
---|
1102 | errnum is set to Z_ERRNO and the application may consult errno |
---|
1103 | to get the exact error code. |
---|
1104 | */ |
---|
1105 | |
---|
1106 | ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); |
---|
1107 | /* |
---|
1108 | Clears the error and end-of-file flags for file. This is analogous to the |
---|
1109 | clearerr() function in stdio. This is useful for continuing to read a gzip |
---|
1110 | file that is being written concurrently. |
---|
1111 | */ |
---|
1112 | |
---|
1113 | /* checksum functions */ |
---|
1114 | |
---|
1115 | /* |
---|
1116 | These functions are not related to compression but are exported |
---|
1117 | anyway because they might be useful in applications using the |
---|
1118 | compression library. |
---|
1119 | */ |
---|
1120 | |
---|
1121 | ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); |
---|
1122 | |
---|
1123 | /* |
---|
1124 | Update a running Adler-32 checksum with the bytes buf[0..len-1] and |
---|
1125 | return the updated checksum. If buf is NULL, this function returns |
---|
1126 | the required initial value for the checksum. |
---|
1127 | An Adler-32 checksum is almost as reliable as a CRC32 but can be computed |
---|
1128 | much faster. Usage example: |
---|
1129 | |
---|
1130 | uLong adler = adler32(0L, Z_NULL, 0); |
---|
1131 | |
---|
1132 | while (read_buffer(buffer, length) != EOF) { |
---|
1133 | adler = adler32(adler, buffer, length); |
---|
1134 | } |
---|
1135 | if (adler != original_adler) error(); |
---|
1136 | */ |
---|
1137 | |
---|
1138 | ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); |
---|
1139 | /* |
---|
1140 | Update a running crc with the bytes buf[0..len-1] and return the updated |
---|
1141 | crc. If buf is NULL, this function returns the required initial value |
---|
1142 | for the crc. Pre- and post-conditioning (one's complement) is performed |
---|
1143 | within this function so it shouldn't be done by the application. |
---|
1144 | Usage example: |
---|
1145 | |
---|
1146 | uLong crc = crc32(0L, Z_NULL, 0); |
---|
1147 | |
---|
1148 | while (read_buffer(buffer, length) != EOF) { |
---|
1149 | crc = crc32(crc, buffer, length); |
---|
1150 | } |
---|
1151 | if (crc != original_crc) error(); |
---|
1152 | */ |
---|
1153 | |
---|
1154 | |
---|
1155 | /* various hacks, don't look :) */ |
---|
1156 | |
---|
1157 | /* deflateInit and inflateInit are macros to allow checking the zlib version |
---|
1158 | * and the compiler's view of z_stream: |
---|
1159 | */ |
---|
1160 | ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, |
---|
1161 | const char *version, int stream_size)); |
---|
1162 | ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, |
---|
1163 | const char *version, int stream_size)); |
---|
1164 | ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, |
---|
1165 | int windowBits, int memLevel, |
---|
1166 | int strategy, const char *version, |
---|
1167 | int stream_size)); |
---|
1168 | ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, |
---|
1169 | const char *version, int stream_size)); |
---|
1170 | ZEXTERN int ZEXPORT inflateBackInit_ OF((z_stream FAR *strm, int windowBits, |
---|
1171 | unsigned char FAR *window, |
---|
1172 | const char *version, |
---|
1173 | int stream_size)); |
---|
1174 | #define deflateInit(strm, level) \ |
---|
1175 | deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) |
---|
1176 | #define inflateInit(strm) \ |
---|
1177 | inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) |
---|
1178 | #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ |
---|
1179 | deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ |
---|
1180 | (strategy), ZLIB_VERSION, sizeof(z_stream)) |
---|
1181 | #define inflateInit2(strm, windowBits) \ |
---|
1182 | inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) |
---|
1183 | #define inflateBackInit(strm, windowBits, window) \ |
---|
1184 | inflateBackInit_((strm), (windowBits), (window), \ |
---|
1185 | ZLIB_VERSION, sizeof(z_stream)) |
---|
1186 | |
---|
1187 | |
---|
1188 | #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) |
---|
1189 | struct internal_state {int dummy;}; /* hack for buggy compilers */ |
---|
1190 | #endif |
---|
1191 | |
---|
1192 | ZEXTERN const char * ZEXPORT zError OF((int err)); |
---|
1193 | ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z)); |
---|
1194 | ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); |
---|
1195 | |
---|
1196 | #ifdef __cplusplus |
---|
1197 | } |
---|
1198 | #endif |
---|
1199 | |
---|
1200 | #endif /* ZLIB_H */ |
---|