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5191 | serge | 1 | /* md5.c - Functions to compute MD5 message digest of files or memory blocks |
2 | according to the definition of MD5 in RFC 1321 from April 1992. |
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3 | Copyright (C) 1995, 1996, 2011 Free Software Foundation, Inc. |
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4 | |||
5 | NOTE: This source is derived from an old version taken from the GNU C |
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6 | Library (glibc). |
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7 | |||
8 | This program is free software; you can redistribute it and/or modify it |
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9 | under the terms of the GNU General Public License as published by the |
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10 | Free Software Foundation; either version 2, or (at your option) any |
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11 | later version. |
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12 | |||
13 | This program is distributed in the hope that it will be useful, |
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14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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16 | GNU General Public License for more details. |
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17 | |||
18 | You should have received a copy of the GNU General Public License |
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19 | along with this program; if not, write to the Free Software Foundation, |
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20 | Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ |
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21 | |||
22 | /* Written by Ulrich Drepper |
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23 | |||
24 | #ifdef HAVE_CONFIG_H |
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25 | # include |
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26 | #endif |
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27 | |||
28 | #include |
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29 | |||
30 | #if STDC_HEADERS || defined _LIBC |
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31 | # include |
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32 | # include |
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33 | #else |
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34 | # ifndef HAVE_MEMCPY |
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35 | # define memcpy(d, s, n) bcopy ((s), (d), (n)) |
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36 | # endif |
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37 | #endif |
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38 | |||
39 | #include "ansidecl.h" |
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40 | #include "md5.h" |
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41 | |||
42 | #ifdef _LIBC |
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43 | # include |
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44 | # if __BYTE_ORDER == __BIG_ENDIAN |
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45 | # define WORDS_BIGENDIAN 1 |
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46 | # endif |
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47 | #endif |
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48 | |||
49 | #ifdef WORDS_BIGENDIAN |
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50 | # define SWAP(n) \ |
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51 | (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24)) |
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52 | #else |
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53 | # define SWAP(n) (n) |
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54 | #endif |
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55 | |||
56 | |||
57 | /* This array contains the bytes used to pad the buffer to the next |
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58 | 64-byte boundary. (RFC 1321, 3.1: Step 1) */ |
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59 | static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ }; |
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60 | |||
61 | |||
62 | /* Initialize structure containing state of computation. |
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63 | (RFC 1321, 3.3: Step 3) */ |
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64 | void |
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65 | md5_init_ctx (struct md5_ctx *ctx) |
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66 | { |
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67 | ctx->A = (md5_uint32) 0x67452301; |
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68 | ctx->B = (md5_uint32) 0xefcdab89; |
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69 | ctx->C = (md5_uint32) 0x98badcfe; |
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70 | ctx->D = (md5_uint32) 0x10325476; |
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71 | |||
72 | ctx->total[0] = ctx->total[1] = 0; |
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73 | ctx->buflen = 0; |
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74 | } |
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75 | |||
76 | /* Put result from CTX in first 16 bytes following RESBUF. The result |
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77 | must be in little endian byte order. |
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78 | |||
79 | IMPORTANT: RESBUF may not be aligned as strongly as MD5_UNIT32 so we |
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80 | put things in a local (aligned) buffer first, then memcpy into RESBUF. */ |
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81 | void * |
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82 | md5_read_ctx (const struct md5_ctx *ctx, void *resbuf) |
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83 | { |
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84 | md5_uint32 buffer[4]; |
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85 | |||
86 | buffer[0] = SWAP (ctx->A); |
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87 | buffer[1] = SWAP (ctx->B); |
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88 | buffer[2] = SWAP (ctx->C); |
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89 | buffer[3] = SWAP (ctx->D); |
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90 | |||
91 | memcpy (resbuf, buffer, 16); |
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92 | |||
93 | return resbuf; |
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94 | } |
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95 | |||
96 | /* Process the remaining bytes in the internal buffer and the usual |
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97 | prolog according to the standard and write the result to RESBUF. |
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98 | |||
99 | IMPORTANT: On some systems it is required that RESBUF is correctly |
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100 | aligned for a 32 bits value. */ |
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101 | void * |
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102 | md5_finish_ctx (struct md5_ctx *ctx, void *resbuf) |
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103 | { |
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104 | /* Take yet unprocessed bytes into account. */ |
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105 | md5_uint32 bytes = ctx->buflen; |
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106 | md5_uint32 swap_bytes; |
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107 | size_t pad; |
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108 | |||
109 | /* Now count remaining bytes. */ |
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110 | ctx->total[0] += bytes; |
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111 | if (ctx->total[0] < bytes) |
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112 | ++ctx->total[1]; |
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113 | |||
114 | pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes; |
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115 | memcpy (&ctx->buffer[bytes], fillbuf, pad); |
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116 | |||
117 | /* Put the 64-bit file length in *bits* at the end of the buffer. |
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118 | Use memcpy to avoid aliasing problems. On most systems, this |
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119 | will be optimized away to the same code. */ |
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120 | swap_bytes = SWAP (ctx->total[0] << 3); |
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121 | memcpy (&ctx->buffer[bytes + pad], &swap_bytes, sizeof (swap_bytes)); |
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122 | swap_bytes = SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 29)); |
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123 | memcpy (&ctx->buffer[bytes + pad + 4], &swap_bytes, sizeof (swap_bytes)); |
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124 | |||
125 | /* Process last bytes. */ |
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126 | md5_process_block (ctx->buffer, bytes + pad + 8, ctx); |
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127 | |||
128 | return md5_read_ctx (ctx, resbuf); |
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129 | } |
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130 | |||
131 | /* Compute MD5 message digest for bytes read from STREAM. The |
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132 | resulting message digest number will be written into the 16 bytes |
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133 | beginning at RESBLOCK. */ |
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134 | int |
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135 | md5_stream (FILE *stream, void *resblock) |
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136 | { |
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137 | /* Important: BLOCKSIZE must be a multiple of 64. */ |
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138 | #define BLOCKSIZE 4096 |
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139 | struct md5_ctx ctx; |
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140 | char buffer[BLOCKSIZE + 72]; |
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141 | size_t sum; |
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142 | |||
143 | /* Initialize the computation context. */ |
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144 | md5_init_ctx (&ctx); |
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145 | |||
146 | /* Iterate over full file contents. */ |
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147 | while (1) |
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148 | { |
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149 | /* We read the file in blocks of BLOCKSIZE bytes. One call of the |
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150 | computation function processes the whole buffer so that with the |
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151 | next round of the loop another block can be read. */ |
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152 | size_t n; |
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153 | sum = 0; |
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154 | |||
155 | /* Read block. Take care for partial reads. */ |
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156 | do |
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157 | { |
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158 | n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream); |
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159 | |||
160 | sum += n; |
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161 | } |
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162 | while (sum < BLOCKSIZE && n != 0); |
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163 | if (n == 0 && ferror (stream)) |
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164 | return 1; |
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165 | |||
166 | /* If end of file is reached, end the loop. */ |
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167 | if (n == 0) |
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168 | break; |
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169 | |||
170 | /* Process buffer with BLOCKSIZE bytes. Note that |
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171 | BLOCKSIZE % 64 == 0 |
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172 | */ |
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173 | md5_process_block (buffer, BLOCKSIZE, &ctx); |
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174 | } |
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175 | |||
176 | /* Add the last bytes if necessary. */ |
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177 | if (sum > 0) |
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178 | md5_process_bytes (buffer, sum, &ctx); |
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179 | |||
180 | /* Construct result in desired memory. */ |
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181 | md5_finish_ctx (&ctx, resblock); |
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182 | return 0; |
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183 | } |
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184 | |||
185 | /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The |
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186 | result is always in little endian byte order, so that a byte-wise |
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187 | output yields to the wanted ASCII representation of the message |
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188 | digest. */ |
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189 | void * |
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190 | md5_buffer (const char *buffer, size_t len, void *resblock) |
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191 | { |
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192 | struct md5_ctx ctx; |
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193 | |||
194 | /* Initialize the computation context. */ |
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195 | md5_init_ctx (&ctx); |
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196 | |||
197 | /* Process whole buffer but last len % 64 bytes. */ |
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198 | md5_process_bytes (buffer, len, &ctx); |
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199 | |||
200 | /* Put result in desired memory area. */ |
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201 | return md5_finish_ctx (&ctx, resblock); |
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202 | } |
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203 | |||
204 | |||
205 | void |
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206 | md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx) |
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207 | { |
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208 | /* When we already have some bits in our internal buffer concatenate |
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209 | both inputs first. */ |
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210 | if (ctx->buflen != 0) |
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211 | { |
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212 | size_t left_over = ctx->buflen; |
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213 | size_t add = 128 - left_over > len ? len : 128 - left_over; |
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214 | |||
215 | memcpy (&ctx->buffer[left_over], buffer, add); |
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216 | ctx->buflen += add; |
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217 | |||
218 | if (left_over + add > 64) |
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219 | { |
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220 | md5_process_block (ctx->buffer, (left_over + add) & ~63, ctx); |
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221 | /* The regions in the following copy operation cannot overlap. */ |
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222 | memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63], |
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223 | (left_over + add) & 63); |
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224 | ctx->buflen = (left_over + add) & 63; |
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225 | } |
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226 | |||
227 | buffer = (const void *) ((const char *) buffer + add); |
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228 | len -= add; |
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229 | } |
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230 | |||
231 | /* Process available complete blocks. */ |
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232 | if (len > 64) |
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233 | { |
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234 | #if !_STRING_ARCH_unaligned |
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235 | /* To check alignment gcc has an appropriate operator. Other |
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236 | compilers don't. */ |
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237 | # if __GNUC__ >= 2 |
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238 | # define UNALIGNED_P(p) (((md5_uintptr) p) % __alignof__ (md5_uint32) != 0) |
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239 | # else |
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240 | # define UNALIGNED_P(p) (((md5_uintptr) p) % sizeof (md5_uint32) != 0) |
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241 | # endif |
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242 | if (UNALIGNED_P (buffer)) |
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243 | while (len > 64) |
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244 | { |
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245 | memcpy (ctx->buffer, buffer, 64); |
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246 | md5_process_block (ctx->buffer, 64, ctx); |
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247 | buffer = (const char *) buffer + 64; |
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248 | len -= 64; |
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249 | } |
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250 | else |
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251 | #endif |
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252 | { |
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253 | md5_process_block (buffer, len & ~63, ctx); |
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254 | buffer = (const void *) ((const char *) buffer + (len & ~63)); |
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255 | len &= 63; |
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256 | } |
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257 | } |
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258 | |||
259 | /* Move remaining bytes in internal buffer. */ |
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260 | if (len > 0) |
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261 | { |
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262 | memcpy (ctx->buffer, buffer, len); |
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263 | ctx->buflen = len; |
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264 | } |
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265 | } |
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266 | |||
267 | |||
268 | /* These are the four functions used in the four steps of the MD5 algorithm |
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269 | and defined in the RFC 1321. The first function is a little bit optimized |
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270 | (as found in Colin Plumbs public domain implementation). */ |
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271 | /* #define FF(b, c, d) ((b & c) | (~b & d)) */ |
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272 | #define FF(b, c, d) (d ^ (b & (c ^ d))) |
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273 | #define FG(b, c, d) FF (d, b, c) |
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274 | #define FH(b, c, d) (b ^ c ^ d) |
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275 | #define FI(b, c, d) (c ^ (b | ~d)) |
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276 | |||
277 | /* Process LEN bytes of BUFFER, accumulating context into CTX. |
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278 | It is assumed that LEN % 64 == 0. */ |
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279 | |||
280 | void |
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281 | md5_process_block (const void *buffer, size_t len, struct md5_ctx *ctx) |
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282 | { |
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283 | md5_uint32 correct_words[16]; |
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284 | const md5_uint32 *words = (const md5_uint32 *) buffer; |
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285 | size_t nwords = len / sizeof (md5_uint32); |
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286 | const md5_uint32 *endp = words + nwords; |
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287 | md5_uint32 A = ctx->A; |
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288 | md5_uint32 B = ctx->B; |
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289 | md5_uint32 C = ctx->C; |
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290 | md5_uint32 D = ctx->D; |
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291 | |||
292 | /* First increment the byte count. RFC 1321 specifies the possible |
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293 | length of the file up to 2^64 bits. Here we only compute the |
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294 | number of bytes. Do a double word increment. */ |
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295 | ctx->total[0] += len; |
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296 | ctx->total[1] += ((len >> 31) >> 1) + (ctx->total[0] < len); |
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297 | |||
298 | /* Process all bytes in the buffer with 64 bytes in each round of |
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299 | the loop. */ |
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300 | while (words < endp) |
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301 | { |
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302 | md5_uint32 *cwp = correct_words; |
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303 | md5_uint32 A_save = A; |
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304 | md5_uint32 B_save = B; |
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305 | md5_uint32 C_save = C; |
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306 | md5_uint32 D_save = D; |
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307 | |||
308 | /* First round: using the given function, the context and a constant |
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309 | the next context is computed. Because the algorithms processing |
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310 | unit is a 32-bit word and it is determined to work on words in |
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311 | little endian byte order we perhaps have to change the byte order |
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312 | before the computation. To reduce the work for the next steps |
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313 | we store the swapped words in the array CORRECT_WORDS. */ |
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314 | |||
315 | #define OP(a, b, c, d, s, T) \ |
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316 | do \ |
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317 | { \ |
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318 | a += FF (b, c, d) + (*cwp++ = SWAP (*words)) + T; \ |
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319 | ++words; \ |
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320 | CYCLIC (a, s); \ |
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321 | a += b; \ |
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322 | } \ |
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323 | while (0) |
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324 | |||
325 | /* It is unfortunate that C does not provide an operator for |
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326 | cyclic rotation. Hope the C compiler is smart enough. */ |
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327 | #define CYCLIC(w, s) (w = (w << s) | (w >> (32 - s))) |
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328 | |||
329 | /* Before we start, one word to the strange constants. |
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330 | They are defined in RFC 1321 as |
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331 | |||
332 | T[i] = (int) (4294967296.0 * fabs (sin (i))), i=1..64 |
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333 | */ |
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334 | |||
335 | /* Round 1. */ |
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336 | OP (A, B, C, D, 7, (md5_uint32) 0xd76aa478); |
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337 | OP (D, A, B, C, 12, (md5_uint32) 0xe8c7b756); |
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338 | OP (C, D, A, B, 17, (md5_uint32) 0x242070db); |
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339 | OP (B, C, D, A, 22, (md5_uint32) 0xc1bdceee); |
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340 | OP (A, B, C, D, 7, (md5_uint32) 0xf57c0faf); |
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341 | OP (D, A, B, C, 12, (md5_uint32) 0x4787c62a); |
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342 | OP (C, D, A, B, 17, (md5_uint32) 0xa8304613); |
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343 | OP (B, C, D, A, 22, (md5_uint32) 0xfd469501); |
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344 | OP (A, B, C, D, 7, (md5_uint32) 0x698098d8); |
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345 | OP (D, A, B, C, 12, (md5_uint32) 0x8b44f7af); |
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346 | OP (C, D, A, B, 17, (md5_uint32) 0xffff5bb1); |
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347 | OP (B, C, D, A, 22, (md5_uint32) 0x895cd7be); |
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348 | OP (A, B, C, D, 7, (md5_uint32) 0x6b901122); |
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349 | OP (D, A, B, C, 12, (md5_uint32) 0xfd987193); |
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350 | OP (C, D, A, B, 17, (md5_uint32) 0xa679438e); |
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351 | OP (B, C, D, A, 22, (md5_uint32) 0x49b40821); |
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352 | |||
353 | /* For the second to fourth round we have the possibly swapped words |
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354 | in CORRECT_WORDS. Redefine the macro to take an additional first |
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355 | argument specifying the function to use. */ |
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356 | #undef OP |
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357 | #define OP(a, b, c, d, k, s, T) \ |
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358 | do \ |
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359 | { \ |
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360 | a += FX (b, c, d) + correct_words[k] + T; \ |
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361 | CYCLIC (a, s); \ |
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362 | a += b; \ |
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363 | } \ |
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364 | while (0) |
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365 | |||
366 | #define FX(b, c, d) FG (b, c, d) |
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367 | |||
368 | /* Round 2. */ |
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369 | OP (A, B, C, D, 1, 5, (md5_uint32) 0xf61e2562); |
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370 | OP (D, A, B, C, 6, 9, (md5_uint32) 0xc040b340); |
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371 | OP (C, D, A, B, 11, 14, (md5_uint32) 0x265e5a51); |
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372 | OP (B, C, D, A, 0, 20, (md5_uint32) 0xe9b6c7aa); |
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373 | OP (A, B, C, D, 5, 5, (md5_uint32) 0xd62f105d); |
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374 | OP (D, A, B, C, 10, 9, (md5_uint32) 0x02441453); |
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375 | OP (C, D, A, B, 15, 14, (md5_uint32) 0xd8a1e681); |
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376 | OP (B, C, D, A, 4, 20, (md5_uint32) 0xe7d3fbc8); |
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377 | OP (A, B, C, D, 9, 5, (md5_uint32) 0x21e1cde6); |
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378 | OP (D, A, B, C, 14, 9, (md5_uint32) 0xc33707d6); |
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379 | OP (C, D, A, B, 3, 14, (md5_uint32) 0xf4d50d87); |
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380 | OP (B, C, D, A, 8, 20, (md5_uint32) 0x455a14ed); |
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381 | OP (A, B, C, D, 13, 5, (md5_uint32) 0xa9e3e905); |
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382 | OP (D, A, B, C, 2, 9, (md5_uint32) 0xfcefa3f8); |
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383 | OP (C, D, A, B, 7, 14, (md5_uint32) 0x676f02d9); |
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384 | OP (B, C, D, A, 12, 20, (md5_uint32) 0x8d2a4c8a); |
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385 | |||
386 | #undef FX |
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387 | #define FX(b, c, d) FH (b, c, d) |
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388 | |||
389 | /* Round 3. */ |
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390 | OP (A, B, C, D, 5, 4, (md5_uint32) 0xfffa3942); |
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391 | OP (D, A, B, C, 8, 11, (md5_uint32) 0x8771f681); |
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392 | OP (C, D, A, B, 11, 16, (md5_uint32) 0x6d9d6122); |
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393 | OP (B, C, D, A, 14, 23, (md5_uint32) 0xfde5380c); |
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394 | OP (A, B, C, D, 1, 4, (md5_uint32) 0xa4beea44); |
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395 | OP (D, A, B, C, 4, 11, (md5_uint32) 0x4bdecfa9); |
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396 | OP (C, D, A, B, 7, 16, (md5_uint32) 0xf6bb4b60); |
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397 | OP (B, C, D, A, 10, 23, (md5_uint32) 0xbebfbc70); |
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398 | OP (A, B, C, D, 13, 4, (md5_uint32) 0x289b7ec6); |
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399 | OP (D, A, B, C, 0, 11, (md5_uint32) 0xeaa127fa); |
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400 | OP (C, D, A, B, 3, 16, (md5_uint32) 0xd4ef3085); |
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401 | OP (B, C, D, A, 6, 23, (md5_uint32) 0x04881d05); |
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402 | OP (A, B, C, D, 9, 4, (md5_uint32) 0xd9d4d039); |
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403 | OP (D, A, B, C, 12, 11, (md5_uint32) 0xe6db99e5); |
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404 | OP (C, D, A, B, 15, 16, (md5_uint32) 0x1fa27cf8); |
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405 | OP (B, C, D, A, 2, 23, (md5_uint32) 0xc4ac5665); |
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406 | |||
407 | #undef FX |
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408 | #define FX(b, c, d) FI (b, c, d) |
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409 | |||
410 | /* Round 4. */ |
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411 | OP (A, B, C, D, 0, 6, (md5_uint32) 0xf4292244); |
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412 | OP (D, A, B, C, 7, 10, (md5_uint32) 0x432aff97); |
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413 | OP (C, D, A, B, 14, 15, (md5_uint32) 0xab9423a7); |
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414 | OP (B, C, D, A, 5, 21, (md5_uint32) 0xfc93a039); |
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415 | OP (A, B, C, D, 12, 6, (md5_uint32) 0x655b59c3); |
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416 | OP (D, A, B, C, 3, 10, (md5_uint32) 0x8f0ccc92); |
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417 | OP (C, D, A, B, 10, 15, (md5_uint32) 0xffeff47d); |
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418 | OP (B, C, D, A, 1, 21, (md5_uint32) 0x85845dd1); |
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419 | OP (A, B, C, D, 8, 6, (md5_uint32) 0x6fa87e4f); |
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420 | OP (D, A, B, C, 15, 10, (md5_uint32) 0xfe2ce6e0); |
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421 | OP (C, D, A, B, 6, 15, (md5_uint32) 0xa3014314); |
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422 | OP (B, C, D, A, 13, 21, (md5_uint32) 0x4e0811a1); |
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423 | OP (A, B, C, D, 4, 6, (md5_uint32) 0xf7537e82); |
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424 | OP (D, A, B, C, 11, 10, (md5_uint32) 0xbd3af235); |
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425 | OP (C, D, A, B, 2, 15, (md5_uint32) 0x2ad7d2bb); |
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426 | OP (B, C, D, A, 9, 21, (md5_uint32) 0xeb86d391); |
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427 | |||
428 | /* Add the starting values of the context. */ |
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429 | A += A_save; |
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430 | B += B_save; |
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431 | C += C_save; |
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432 | D += D_save; |
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433 | } |
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434 | |||
435 | /* Put checksum in context given as argument. */ |
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436 | ctx->A = A; |
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437 | ctx->B = B; |
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438 | ctx->C = C; |
||
439 | ctx->D = D; |
||
440 | }><>>>>><>><>>><>><> |