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1 /* md5.c - Functions to compute MD5 message digest of files or memory blocks |
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2 according to the definition of MD5 in RFC 1321 from April 1992. |
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3 Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc. |
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4 This file is part of the GNU C Library. |
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5 |
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6 The GNU C Library is free software; you can redistribute it and/or |
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7 modify it under the terms of the GNU Library General Public License as |
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8 published by the Free Software Foundation; either version 2 of the |
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9 License, or (at your option) any later version. |
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10 |
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11 The GNU C Library is distributed in the hope that it will be useful, |
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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14 Library General Public License for more details. |
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15 |
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16 You should have received a copy of the GNU Library General Public |
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17 License along with the GNU C Library; see the file COPYING.LIB. If not, |
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18 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
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19 Boston, MA 02111-1307, USA. */ |
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20 |
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21 /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */ |
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22 |
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23 #ifdef HAVE_CONFIG_H |
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24 # include <config.h> |
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25 #endif |
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26 |
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27 #include <sys/types.h> |
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28 |
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29 #if STDC_HEADERS || defined _LIBC |
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30 # include <stdlib.h> |
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31 # include <string.h> |
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32 #else |
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33 # ifndef HAVE_MEMCPY |
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34 # define memcpy(d, s, n) bcopy ((s), (d), (n)) |
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35 # endif |
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36 #endif |
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37 |
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38 #include "md5.h" |
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39 |
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40 #ifdef _LIBC |
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41 # include <endian.h> |
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42 # if __BYTE_ORDER == __BIG_ENDIAN |
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43 # define WORDS_BIGENDIAN 1 |
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44 # endif |
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45 /* We need to keep the namespace clean so define the MD5 function |
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46 protected using leading __ and use weak aliases. */ |
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47 # define md5_init_ctx __md5_init_ctx |
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48 # define md5_process_block __md5_process_block |
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49 # define md5_process_bytes __md5_process_bytes |
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50 # define md5_finish_ctx __md5_finish_ctx |
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51 # define md5_read_ctx __md5_read_ctx |
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52 # define md5_stream __md5_stream |
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53 # define md5_buffer __md5_buffer |
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54 #endif |
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55 |
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56 #ifdef WORDS_BIGENDIAN |
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57 # define SWAP(n) \ |
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58 (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24)) |
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59 #else |
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60 # define SWAP(n) (n) |
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61 #endif |
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62 |
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63 |
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64 /* This array contains the bytes used to pad the buffer to the next |
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65 64-byte boundary. (RFC 1321, 3.1: Step 1) */ |
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66 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ }; |
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67 |
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68 |
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69 /* Initialize structure containing state of computation. |
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70 (RFC 1321, 3.3: Step 3) */ |
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71 void |
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72 md5_init_ctx (ctx) |
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73 struct md5_ctx *ctx; |
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74 { |
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75 ctx->A = 0x67452301; |
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76 ctx->B = 0xefcdab89; |
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77 ctx->C = 0x98badcfe; |
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78 ctx->D = 0x10325476; |
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79 |
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80 ctx->total[0] = ctx->total[1] = 0; |
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81 ctx->buflen = 0; |
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82 } |
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83 |
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84 /* Put result from CTX in first 16 bytes following RESBUF. The result |
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85 must be in little endian byte order. |
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86 |
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87 IMPORTANT: On some systems it is required that RESBUF is correctly |
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88 aligned for a 32 bits value. */ |
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89 void * |
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90 md5_read_ctx (ctx, resbuf) |
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91 const struct md5_ctx *ctx; |
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92 void *resbuf; |
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93 { |
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94 ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A); |
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95 ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B); |
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96 ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C); |
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97 ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D); |
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98 |
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99 return resbuf; |
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100 } |
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101 |
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102 /* Process the remaining bytes in the internal buffer and the usual |
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103 prolog according to the standard and write the result to RESBUF. |
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104 |
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105 IMPORTANT: On some systems it is required that RESBUF is correctly |
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106 aligned for a 32 bits value. */ |
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107 void * |
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108 md5_finish_ctx (ctx, resbuf) |
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109 struct md5_ctx *ctx; |
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110 void *resbuf; |
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111 { |
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112 /* Take yet unprocessed bytes into account. */ |
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113 md5_uint32 bytes = ctx->buflen; |
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114 size_t pad; |
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115 |
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116 /* Now count remaining bytes. */ |
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117 ctx->total[0] += bytes; |
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118 if (ctx->total[0] < bytes) |
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119 ++ctx->total[1]; |
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120 |
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121 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes; |
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122 memcpy (&ctx->buffer[bytes], fillbuf, pad); |
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123 |
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124 /* Put the 64-bit file length in *bits* at the end of the buffer. */ |
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125 *(md5_uint32 *) &ctx->buffer[bytes + pad] = SWAP (ctx->total[0] << 3); |
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126 *(md5_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP ((ctx->total[1] << 3) | |
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127 (ctx->total[0] >> 29)); |
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128 |
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129 /* Process last bytes. */ |
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130 md5_process_block (ctx->buffer, bytes + pad + 8, ctx); |
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131 |
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132 return md5_read_ctx (ctx, resbuf); |
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133 } |
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134 |
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135 /* Compute MD5 message digest for bytes read from STREAM. The |
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136 resulting message digest number will be written into the 16 bytes |
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137 beginning at RESBLOCK. */ |
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138 int |
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139 md5_stream (stream, resblock) |
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140 FILE *stream; |
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141 void *resblock; |
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142 { |
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143 /* Important: BLOCKSIZE must be a multiple of 64. */ |
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144 #define BLOCKSIZE 4096 |
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145 struct md5_ctx ctx; |
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146 char buffer[BLOCKSIZE + 72]; |
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147 size_t sum; |
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148 |
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149 /* Initialize the computation context. */ |
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150 md5_init_ctx (&ctx); |
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151 |
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152 /* Iterate over full file contents. */ |
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153 while (1) |
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154 { |
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155 /* We read the file in blocks of BLOCKSIZE bytes. One call of the |
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156 computation function processes the whole buffer so that with the |
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157 next round of the loop another block can be read. */ |
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158 size_t n; |
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159 sum = 0; |
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160 |
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161 /* Read block. Take care for partial reads. */ |
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162 do |
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163 { |
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164 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream); |
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165 |
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166 sum += n; |
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167 } |
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168 while (sum < BLOCKSIZE && n != 0); |
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169 if (n == 0 && ferror (stream)) |
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170 return 1; |
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171 |
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172 /* If end of file is reached, end the loop. */ |
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173 if (n == 0) |
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174 break; |
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175 |
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176 /* Process buffer with BLOCKSIZE bytes. Note that |
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177 BLOCKSIZE % 64 == 0 |
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178 */ |
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179 md5_process_block (buffer, BLOCKSIZE, &ctx); |
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180 } |
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181 |
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182 /* Add the last bytes if necessary. */ |
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183 if (sum > 0) |
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184 md5_process_bytes (buffer, sum, &ctx); |
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185 |
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186 /* Construct result in desired memory. */ |
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187 md5_finish_ctx (&ctx, resblock); |
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188 return 0; |
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189 } |
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190 |
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191 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The |
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192 result is always in little endian byte order, so that a byte-wise |
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193 output yields to the wanted ASCII representation of the message |
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194 digest. */ |
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195 void * |
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196 md5_buffer (buffer, len, resblock) |
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197 const char *buffer; |
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198 size_t len; |
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199 void *resblock; |
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200 { |
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201 struct md5_ctx ctx; |
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202 |
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203 /* Initialize the computation context. */ |
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204 md5_init_ctx (&ctx); |
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205 |
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206 /* Process whole buffer but last len % 64 bytes. */ |
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207 md5_process_bytes (buffer, len, &ctx); |
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208 |
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209 /* Put result in desired memory area. */ |
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210 return md5_finish_ctx (&ctx, resblock); |
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211 } |
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212 |
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213 |
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214 void |
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215 md5_process_bytes (buffer, len, ctx) |
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216 const void *buffer; |
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217 size_t len; |
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218 struct md5_ctx *ctx; |
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219 { |
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220 /* When we already have some bits in our internal buffer concatenate |
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221 both inputs first. */ |
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222 if (ctx->buflen != 0) |
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223 { |
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224 size_t left_over = ctx->buflen; |
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225 size_t add = 128 - left_over > len ? len : 128 - left_over; |
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226 |
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227 memcpy (&ctx->buffer[left_over], buffer, add); |
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228 ctx->buflen += add; |
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229 |
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230 if (left_over + add > 64) |
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231 { |
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232 md5_process_block (ctx->buffer, (left_over + add) & ~63, ctx); |
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233 /* The regions in the following copy operation cannot overlap. */ |
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234 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63], |
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235 (left_over + add) & 63); |
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236 ctx->buflen = (left_over + add) & 63; |
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237 } |
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238 |
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239 buffer = (const char *) buffer + add; |
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240 len -= add; |
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241 } |
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242 |
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243 /* Process available complete blocks. */ |
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244 if (len > 64) |
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245 { |
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246 md5_process_block (buffer, len & ~63, ctx); |
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247 buffer = (const char *) buffer + (len & ~63); |
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248 len &= 63; |
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249 } |
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250 |
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251 /* Move remaining bytes in internal buffer. */ |
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252 if (len > 0) |
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253 { |
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254 memcpy (ctx->buffer, buffer, len); |
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255 ctx->buflen = len; |
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256 } |
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257 } |
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258 |
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259 |
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260 /* These are the four functions used in the four steps of the MD5 algorithm |
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261 and defined in the RFC 1321. The first function is a little bit optimized |
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262 (as found in Colin Plumbs public domain implementation). */ |
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263 /* #define FF(b, c, d) ((b & c) | (~b & d)) */ |
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264 #define FF(b, c, d) (d ^ (b & (c ^ d))) |
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265 #define FG(b, c, d) FF (d, b, c) |
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266 #define FH(b, c, d) (b ^ c ^ d) |
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267 #define FI(b, c, d) (c ^ (b | ~d)) |
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268 |
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269 /* Process LEN bytes of BUFFER, accumulating context into CTX. |
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270 It is assumed that LEN % 64 == 0. */ |
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271 |
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272 void |
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273 md5_process_block (buffer, len, ctx) |
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274 const void *buffer; |
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275 size_t len; |
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276 struct md5_ctx *ctx; |
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277 { |
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278 md5_uint32 correct_words[16]; |
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279 const md5_uint32 *words = buffer; |
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280 size_t nwords = len / sizeof (md5_uint32); |
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281 const md5_uint32 *endp = words + nwords; |
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282 md5_uint32 A = ctx->A; |
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283 md5_uint32 B = ctx->B; |
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284 md5_uint32 C = ctx->C; |
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285 md5_uint32 D = ctx->D; |
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286 |
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287 /* First increment the byte count. RFC 1321 specifies the possible |
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288 length of the file up to 2^64 bits. Here we only compute the |
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289 number of bytes. Do a double word increment. */ |
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290 ctx->total[0] += len; |
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291 if (ctx->total[0] < len) |
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292 ++ctx->total[1]; |
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293 |
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294 /* Process all bytes in the buffer with 64 bytes in each round of |
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295 the loop. */ |
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296 while (words < endp) |
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297 { |
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298 md5_uint32 *cwp = correct_words; |
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299 md5_uint32 A_save = A; |
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300 md5_uint32 B_save = B; |
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301 md5_uint32 C_save = C; |
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302 md5_uint32 D_save = D; |
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303 |
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304 /* First round: using the given function, the context and a constant |
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305 the next context is computed. Because the algorithms processing |
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306 unit is a 32-bit word and it is determined to work on words in |
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307 little endian byte order we perhaps have to change the byte order |
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308 before the computation. To reduce the work for the next steps |
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309 we store the swapped words in the array CORRECT_WORDS. */ |
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310 |
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311 #define OP(a, b, c, d, s, T) \ |
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312 do \ |
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313 { \ |
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314 a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \ |
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315 ++words; \ |
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316 CYCLIC (a, s); \ |
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317 a += b; \ |
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318 } \ |
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319 while (0) |
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320 |
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321 /* It is unfortunate that C does not provide an operator for |
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322 cyclic rotation. Hope the C compiler is smart enough. */ |
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323 #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s))) |
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324 |
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325 /* Before we start, one word to the strange constants. |
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326 They are defined in RFC 1321 as |
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327 |
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328 T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64 |
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329 */ |
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330 |
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331 /* Round 1. */ |
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332 OP (A, B, C, D, 7, 0xd76aa478); |
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333 OP (D, A, B, C, 12, 0xe8c7b756); |
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334 OP (C, D, A, B, 17, 0x242070db); |
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335 OP (B, C, D, A, 22, 0xc1bdceee); |
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336 OP (A, B, C, D, 7, 0xf57c0faf); |
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337 OP (D, A, B, C, 12, 0x4787c62a); |
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338 OP (C, D, A, B, 17, 0xa8304613); |
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339 OP (B, C, D, A, 22, 0xfd469501); |
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340 OP (A, B, C, D, 7, 0x698098d8); |
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341 OP (D, A, B, C, 12, 0x8b44f7af); |
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342 OP (C, D, A, B, 17, 0xffff5bb1); |
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343 OP (B, C, D, A, 22, 0x895cd7be); |
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344 OP (A, B, C, D, 7, 0x6b901122); |
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345 OP (D, A, B, C, 12, 0xfd987193); |
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346 OP (C, D, A, B, 17, 0xa679438e); |
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347 OP (B, C, D, A, 22, 0x49b40821); |
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348 |
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349 /* For the second to fourth round we have the possibly swapped words |
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350 in CORRECT_WORDS. Redefine the macro to take an additional first |
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351 argument specifying the function to use. */ |
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352 #undef OP |
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353 #define OP(f, a, b, c, d, k, s, T) \ |
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354 do \ |
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355 { \ |
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356 a += f (b, c, d) + correct_words[k] + T; \ |
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357 CYCLIC (a, s); \ |
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358 a += b; \ |
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359 } \ |
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360 while (0) |
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361 |
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362 /* Round 2. */ |
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363 OP (FG, A, B, C, D, 1, 5, 0xf61e2562); |
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364 OP (FG, D, A, B, C, 6, 9, 0xc040b340); |
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365 OP (FG, C, D, A, B, 11, 14, 0x265e5a51); |
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366 OP (FG, B, C, D, A, 0, 20, 0xe9b6c7aa); |
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367 OP (FG, A, B, C, D, 5, 5, 0xd62f105d); |
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368 OP (FG, D, A, B, C, 10, 9, 0x02441453); |
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369 OP (FG, C, D, A, B, 15, 14, 0xd8a1e681); |
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370 OP (FG, B, C, D, A, 4, 20, 0xe7d3fbc8); |
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371 OP (FG, A, B, C, D, 9, 5, 0x21e1cde6); |
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372 OP (FG, D, A, B, C, 14, 9, 0xc33707d6); |
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373 OP (FG, C, D, A, B, 3, 14, 0xf4d50d87); |
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374 OP (FG, B, C, D, A, 8, 20, 0x455a14ed); |
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375 OP (FG, A, B, C, D, 13, 5, 0xa9e3e905); |
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376 OP (FG, D, A, B, C, 2, 9, 0xfcefa3f8); |
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377 OP (FG, C, D, A, B, 7, 14, 0x676f02d9); |
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378 OP (FG, B, C, D, A, 12, 20, 0x8d2a4c8a); |
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379 |
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380 /* Round 3. */ |
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381 OP (FH, A, B, C, D, 5, 4, 0xfffa3942); |
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382 OP (FH, D, A, B, C, 8, 11, 0x8771f681); |
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383 OP (FH, C, D, A, B, 11, 16, 0x6d9d6122); |
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384 OP (FH, B, C, D, A, 14, 23, 0xfde5380c); |
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385 OP (FH, A, B, C, D, 1, 4, 0xa4beea44); |
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386 OP (FH, D, A, B, C, 4, 11, 0x4bdecfa9); |
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387 OP (FH, C, D, A, B, 7, 16, 0xf6bb4b60); |
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388 OP (FH, B, C, D, A, 10, 23, 0xbebfbc70); |
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389 OP (FH, A, B, C, D, 13, 4, 0x289b7ec6); |
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390 OP (FH, D, A, B, C, 0, 11, 0xeaa127fa); |
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391 OP (FH, C, D, A, B, 3, 16, 0xd4ef3085); |
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392 OP (FH, B, C, D, A, 6, 23, 0x04881d05); |
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393 OP (FH, A, B, C, D, 9, 4, 0xd9d4d039); |
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394 OP (FH, D, A, B, C, 12, 11, 0xe6db99e5); |
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395 OP (FH, C, D, A, B, 15, 16, 0x1fa27cf8); |
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396 OP (FH, B, C, D, A, 2, 23, 0xc4ac5665); |
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397 |
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398 /* Round 4. */ |
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399 OP (FI, A, B, C, D, 0, 6, 0xf4292244); |
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400 OP (FI, D, A, B, C, 7, 10, 0x432aff97); |
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401 OP (FI, C, D, A, B, 14, 15, 0xab9423a7); |
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402 OP (FI, B, C, D, A, 5, 21, 0xfc93a039); |
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403 OP (FI, A, B, C, D, 12, 6, 0x655b59c3); |
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404 OP (FI, D, A, B, C, 3, 10, 0x8f0ccc92); |
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405 OP (FI, C, D, A, B, 10, 15, 0xffeff47d); |
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406 OP (FI, B, C, D, A, 1, 21, 0x85845dd1); |
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407 OP (FI, A, B, C, D, 8, 6, 0x6fa87e4f); |
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408 OP (FI, D, A, B, C, 15, 10, 0xfe2ce6e0); |
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409 OP (FI, C, D, A, B, 6, 15, 0xa3014314); |
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410 OP (FI, B, C, D, A, 13, 21, 0x4e0811a1); |
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411 OP (FI, A, B, C, D, 4, 6, 0xf7537e82); |
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412 OP (FI, D, A, B, C, 11, 10, 0xbd3af235); |
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413 OP (FI, C, D, A, B, 2, 15, 0x2ad7d2bb); |
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414 OP (FI, B, C, D, A, 9, 21, 0xeb86d391); |
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415 |
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416 /* Add the starting values of the context. */ |
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417 A += A_save; |
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418 B += B_save; |
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419 C += C_save; |
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420 D += D_save; |
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421 } |
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422 |
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423 /* Put checksum in context given as argument. */ |
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424 ctx->A = A; |
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425 ctx->B = B; |
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426 ctx->C = C; |
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427 ctx->D = D; |
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428 } |
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429 |
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430 |
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431 #ifdef _LIBC |
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432 /* Define weak aliases. */ |
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433 # undef md5_init_ctx |
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434 weak_alias (__md5_init_ctx, md5_init_ctx) |
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435 # undef md5_process_block |
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436 weak_alias (__md5_process_block, md5_process_block) |
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437 # undef md5_process_bytes |
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438 weak_alias (__md5_process_bytes, md5_process_bytes) |
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439 # undef md5_finish_ctx |
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440 weak_alias (__md5_finish_ctx, md5_finish_ctx) |
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441 # undef md5_read_ctx |
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442 weak_alias (__md5_read_ctx, md5_read_ctx) |
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443 # undef md5_stream |
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444 weak_alias (__md5_stream, md5_stream) |
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445 # undef md5_buffer |
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446 weak_alias (__md5_buffer, md5_buffer) |
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447 #endif |