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comparison: gfx/skia/trunk/src/utils/SkMD5.cpp

gfx/skia/trunk/src/utils/SkMD5.cpp

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TOR_BUG_9701
changeset 15
b8a032363ba2
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-1:000000000000 0:6da7fc7159df
1 /*
2 * Copyright 2012 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 *
7 * The following code is based on the description in RFC 1321.
8 * http://www.ietf.org/rfc/rfc1321.txt
9 */
10
11 #include "SkTypes.h"
12 #include "SkMD5.h"
13 #include <string.h>
14
15 /** MD5 basic transformation. Transforms state based on block. */
16 static void transform(uint32_t state[4], const uint8_t block[64]);
17
18 /** Encodes input into output (4 little endian 32 bit values). */
19 static void encode(uint8_t output[16], const uint32_t input[4]);
20
21 /** Encodes input into output (little endian 64 bit value). */
22 static void encode(uint8_t output[8], const uint64_t input);
23
24 /** Decodes input (4 little endian 32 bit values) into storage, if required. */
25 static const uint32_t* decode(uint32_t storage[16], const uint8_t input[64]);
26
27 SkMD5::SkMD5() : byteCount(0) {
28 // These are magic numbers from the specification.
29 this->state[0] = 0x67452301;
30 this->state[1] = 0xefcdab89;
31 this->state[2] = 0x98badcfe;
32 this->state[3] = 0x10325476;
33 }
34
35 void SkMD5::update(const uint8_t* input, size_t inputLength) {
36 unsigned int bufferIndex = (unsigned int)(this->byteCount & 0x3F);
37 unsigned int bufferAvailable = 64 - bufferIndex;
38
39 unsigned int inputIndex;
40 if (inputLength >= bufferAvailable) {
41 if (bufferIndex) {
42 memcpy(&this->buffer[bufferIndex], input, bufferAvailable);
43 transform(this->state, this->buffer);
44 inputIndex = bufferAvailable;
45 } else {
46 inputIndex = 0;
47 }
48
49 for (; inputIndex + 63 < inputLength; inputIndex += 64) {
50 transform(this->state, &input[inputIndex]);
51 }
52
53 bufferIndex = 0;
54 } else {
55 inputIndex = 0;
56 }
57
58 memcpy(&this->buffer[bufferIndex], &input[inputIndex], inputLength - inputIndex);
59
60 this->byteCount += inputLength;
61 }
62
63 void SkMD5::finish(Digest& digest) {
64 // Get the number of bits before padding.
65 uint8_t bits[8];
66 encode(bits, this->byteCount << 3);
67
68 // Pad out to 56 mod 64.
69 unsigned int bufferIndex = (unsigned int)(this->byteCount & 0x3F);
70 unsigned int paddingLength = (bufferIndex < 56) ? (56 - bufferIndex) : (120 - bufferIndex);
71 static uint8_t PADDING[64] = {
72 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
73 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
74 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
75 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
76 };
77 this->update(PADDING, paddingLength);
78
79 // Append length (length before padding, will cause final update).
80 this->update(bits, 8);
81
82 // Write out digest.
83 encode(digest.data, this->state);
84
85 #if defined(SK_MD5_CLEAR_DATA)
86 // Clear state.
87 memset(this, 0, sizeof(*this));
88 #endif
89 }
90
91 struct F { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) {
92 //return (x & y) | ((~x) & z);
93 return ((y ^ z) & x) ^ z; //equivelent but faster
94 }};
95
96 struct G { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) {
97 return (x & z) | (y & (~z));
98 //return ((x ^ y) & z) ^ y; //equivelent but slower
99 }};
100
101 struct H { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) {
102 return x ^ y ^ z;
103 }};
104
105 struct I { uint32_t operator()(uint32_t x, uint32_t y, uint32_t z) {
106 return y ^ (x | (~z));
107 }};
108
109 /** Rotates x left n bits. */
110 static inline uint32_t rotate_left(uint32_t x, uint8_t n) {
111 return (x << n) | (x >> (32 - n));
112 }
113
114 template <typename T>
115 static inline void operation(T operation, uint32_t& a, uint32_t b, uint32_t c, uint32_t d,
116 uint32_t x, uint8_t s, uint32_t t) {
117 a = b + rotate_left(a + operation(b, c, d) + x + t, s);
118 }
119
120 static void transform(uint32_t state[4], const uint8_t block[64]) {
121 uint32_t a = state[0], b = state[1], c = state[2], d = state[3];
122
123 uint32_t storage[16];
124 const uint32_t* X = decode(storage, block);
125
126 // Round 1
127 operation(F(), a, b, c, d, X[ 0], 7, 0xd76aa478); // 1
128 operation(F(), d, a, b, c, X[ 1], 12, 0xe8c7b756); // 2
129 operation(F(), c, d, a, b, X[ 2], 17, 0x242070db); // 3
130 operation(F(), b, c, d, a, X[ 3], 22, 0xc1bdceee); // 4
131 operation(F(), a, b, c, d, X[ 4], 7, 0xf57c0faf); // 5
132 operation(F(), d, a, b, c, X[ 5], 12, 0x4787c62a); // 6
133 operation(F(), c, d, a, b, X[ 6], 17, 0xa8304613); // 7
134 operation(F(), b, c, d, a, X[ 7], 22, 0xfd469501); // 8
135 operation(F(), a, b, c, d, X[ 8], 7, 0x698098d8); // 9
136 operation(F(), d, a, b, c, X[ 9], 12, 0x8b44f7af); // 10
137 operation(F(), c, d, a, b, X[10], 17, 0xffff5bb1); // 11
138 operation(F(), b, c, d, a, X[11], 22, 0x895cd7be); // 12
139 operation(F(), a, b, c, d, X[12], 7, 0x6b901122); // 13
140 operation(F(), d, a, b, c, X[13], 12, 0xfd987193); // 14
141 operation(F(), c, d, a, b, X[14], 17, 0xa679438e); // 15
142 operation(F(), b, c, d, a, X[15], 22, 0x49b40821); // 16
143
144 // Round 2
145 operation(G(), a, b, c, d, X[ 1], 5, 0xf61e2562); // 17
146 operation(G(), d, a, b, c, X[ 6], 9, 0xc040b340); // 18
147 operation(G(), c, d, a, b, X[11], 14, 0x265e5a51); // 19
148 operation(G(), b, c, d, a, X[ 0], 20, 0xe9b6c7aa); // 20
149 operation(G(), a, b, c, d, X[ 5], 5, 0xd62f105d); // 21
150 operation(G(), d, a, b, c, X[10], 9, 0x2441453); // 22
151 operation(G(), c, d, a, b, X[15], 14, 0xd8a1e681); // 23
152 operation(G(), b, c, d, a, X[ 4], 20, 0xe7d3fbc8); // 24
153 operation(G(), a, b, c, d, X[ 9], 5, 0x21e1cde6); // 25
154 operation(G(), d, a, b, c, X[14], 9, 0xc33707d6); // 26
155 operation(G(), c, d, a, b, X[ 3], 14, 0xf4d50d87); // 27
156 operation(G(), b, c, d, a, X[ 8], 20, 0x455a14ed); // 28
157 operation(G(), a, b, c, d, X[13], 5, 0xa9e3e905); // 29
158 operation(G(), d, a, b, c, X[ 2], 9, 0xfcefa3f8); // 30
159 operation(G(), c, d, a, b, X[ 7], 14, 0x676f02d9); // 31
160 operation(G(), b, c, d, a, X[12], 20, 0x8d2a4c8a); // 32
161
162 // Round 3
163 operation(H(), a, b, c, d, X[ 5], 4, 0xfffa3942); // 33
164 operation(H(), d, a, b, c, X[ 8], 11, 0x8771f681); // 34
165 operation(H(), c, d, a, b, X[11], 16, 0x6d9d6122); // 35
166 operation(H(), b, c, d, a, X[14], 23, 0xfde5380c); // 36
167 operation(H(), a, b, c, d, X[ 1], 4, 0xa4beea44); // 37
168 operation(H(), d, a, b, c, X[ 4], 11, 0x4bdecfa9); // 38
169 operation(H(), c, d, a, b, X[ 7], 16, 0xf6bb4b60); // 39
170 operation(H(), b, c, d, a, X[10], 23, 0xbebfbc70); // 40
171 operation(H(), a, b, c, d, X[13], 4, 0x289b7ec6); // 41
172 operation(H(), d, a, b, c, X[ 0], 11, 0xeaa127fa); // 42
173 operation(H(), c, d, a, b, X[ 3], 16, 0xd4ef3085); // 43
174 operation(H(), b, c, d, a, X[ 6], 23, 0x4881d05); // 44
175 operation(H(), a, b, c, d, X[ 9], 4, 0xd9d4d039); // 45
176 operation(H(), d, a, b, c, X[12], 11, 0xe6db99e5); // 46
177 operation(H(), c, d, a, b, X[15], 16, 0x1fa27cf8); // 47
178 operation(H(), b, c, d, a, X[ 2], 23, 0xc4ac5665); // 48
179
180 // Round 4
181 operation(I(), a, b, c, d, X[ 0], 6, 0xf4292244); // 49
182 operation(I(), d, a, b, c, X[ 7], 10, 0x432aff97); // 50
183 operation(I(), c, d, a, b, X[14], 15, 0xab9423a7); // 51
184 operation(I(), b, c, d, a, X[ 5], 21, 0xfc93a039); // 52
185 operation(I(), a, b, c, d, X[12], 6, 0x655b59c3); // 53
186 operation(I(), d, a, b, c, X[ 3], 10, 0x8f0ccc92); // 54
187 operation(I(), c, d, a, b, X[10], 15, 0xffeff47d); // 55
188 operation(I(), b, c, d, a, X[ 1], 21, 0x85845dd1); // 56
189 operation(I(), a, b, c, d, X[ 8], 6, 0x6fa87e4f); // 57
190 operation(I(), d, a, b, c, X[15], 10, 0xfe2ce6e0); // 58
191 operation(I(), c, d, a, b, X[ 6], 15, 0xa3014314); // 59
192 operation(I(), b, c, d, a, X[13], 21, 0x4e0811a1); // 60
193 operation(I(), a, b, c, d, X[ 4], 6, 0xf7537e82); // 61
194 operation(I(), d, a, b, c, X[11], 10, 0xbd3af235); // 62
195 operation(I(), c, d, a, b, X[ 2], 15, 0x2ad7d2bb); // 63
196 operation(I(), b, c, d, a, X[ 9], 21, 0xeb86d391); // 64
197
198 state[0] += a;
199 state[1] += b;
200 state[2] += c;
201 state[3] += d;
202
203 #if defined(SK_MD5_CLEAR_DATA)
204 // Clear sensitive information.
205 if (X == &storage) {
206 memset(storage, 0, sizeof(storage));
207 }
208 #endif
209 }
210
211 static void encode(uint8_t output[16], const uint32_t input[4]) {
212 for (size_t i = 0, j = 0; i < 4; i++, j += 4) {
213 output[j ] = (uint8_t) (input[i] & 0xff);
214 output[j+1] = (uint8_t)((input[i] >> 8) & 0xff);
215 output[j+2] = (uint8_t)((input[i] >> 16) & 0xff);
216 output[j+3] = (uint8_t)((input[i] >> 24) & 0xff);
217 }
218 }
219
220 static void encode(uint8_t output[8], const uint64_t input) {
221 output[0] = (uint8_t) (input & 0xff);
222 output[1] = (uint8_t)((input >> 8) & 0xff);
223 output[2] = (uint8_t)((input >> 16) & 0xff);
224 output[3] = (uint8_t)((input >> 24) & 0xff);
225 output[4] = (uint8_t)((input >> 32) & 0xff);
226 output[5] = (uint8_t)((input >> 40) & 0xff);
227 output[6] = (uint8_t)((input >> 48) & 0xff);
228 output[7] = (uint8_t)((input >> 56) & 0xff);
229 }
230
231 static inline bool is_aligned(const void *pointer, size_t byte_count) {
232 return reinterpret_cast<uintptr_t>(pointer) % byte_count == 0;
233 }
234
235 static const uint32_t* decode(uint32_t storage[16], const uint8_t input[64]) {
236 #if defined(SK_CPU_LENDIAN) && defined(SK_CPU_FAST_UNALIGNED_ACCESS)
237 return reinterpret_cast<const uint32_t*>(input);
238 #else
239 #if defined(SK_CPU_LENDIAN)
240 if (is_aligned(input, 4)) {
241 return reinterpret_cast<const uint32_t*>(input);
242 }
243 #endif
244 for (size_t i = 0, j = 0; j < 64; i++, j += 4) {
245 storage[i] = ((uint32_t)input[j ]) |
246 (((uint32_t)input[j+1]) << 8) |
247 (((uint32_t)input[j+2]) << 16) |
248 (((uint32_t)input[j+3]) << 24);
249 }
250 return storage;
251 #endif
252 }

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