base85.c: have SP around arithmetic operators
[git/git.git] / block-sha1 / sha1.c
CommitLineData
d7c208a9 1/*
30ae47b4 2 * SHA1 routine optimized to do word accesses rather than byte accesses,
d7c208a9 3 * and to avoid unnecessary copies into the context array.
30ae47b4
NP
4 *
5 * This was initially based on the Mozilla SHA1 implementation, although
6 * none of the original Mozilla code remains.
d7c208a9
LT
7 */
8
51ea5519
NP
9/* this is only to get definitions for memcpy(), ntohl() and htonl() */
10#include "../git-compat-util.h"
d7c208a9
LT
11
12#include "sha1.h"
13
e9c5dcd1 14#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
b8e48a89 15
dc52fd29
NP
16/*
17 * Force usage of rol or ror by selecting the one with the smaller constant.
18 * It _can_ generate slightly smaller code (a constant of 1 is special), but
19 * perhaps more importantly it's possibly faster on any uarch that does a
20 * rotate with a loop.
21 */
22
fd536d34 23#define SHA_ASM(op, x, n) ({ unsigned int __res; __asm__(op " %1,%0":"=r" (__res):"i" (n), "0" (x)); __res; })
b8e48a89
LT
24#define SHA_ROL(x,n) SHA_ASM("rol", x, n)
25#define SHA_ROR(x,n) SHA_ASM("ror", x, n)
26
27#else
28
fd536d34 29#define SHA_ROT(X,l,r) (((X) << (l)) | ((X) >> (r)))
b8e48a89
LT
30#define SHA_ROL(X,n) SHA_ROT(X,n,32-(n))
31#define SHA_ROR(X,n) SHA_ROT(X,32-(n),n)
32
33#endif
d7c208a9 34
926172c5
LT
35/*
36 * If you have 32 registers or more, the compiler can (and should)
37 * try to change the array[] accesses into registers. However, on
38 * machines with less than ~25 registers, that won't really work,
39 * and at least gcc will make an unholy mess of it.
40 *
41 * So to avoid that mess which just slows things down, we force
42 * the stores to memory to actually happen (we might be better off
43 * with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as
44 * suggested by Artur Skawina - that will also make gcc unable to
45 * try to do the silly "optimize away loads" part because it won't
46 * see what the value will be).
47 *
48 * Ben Herrenschmidt reports that on PPC, the C version comes close
49 * to the optimized asm with this (ie on PPC you don't want that
50 * 'volatile', since there are lots of registers).
dc52fd29
NP
51 *
52 * On ARM we get the best code generation by forcing a full memory barrier
53 * between each SHA_ROUND, otherwise gcc happily get wild with spilling and
54 * the stack frame size simply explode and performance goes down the drain.
926172c5 55 */
dc52fd29
NP
56
57#if defined(__i386__) || defined(__x86_64__)
926172c5 58 #define setW(x, val) (*(volatile unsigned int *)&W(x) = (val))
e9c5dcd1 59#elif defined(__GNUC__) && defined(__arm__)
dc52fd29 60 #define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0)
926172c5
LT
61#else
62 #define setW(x, val) (W(x) = (val))
63#endif
ab14c823 64
660231aa
NP
65/*
66 * Performance might be improved if the CPU architecture is OK with
67 * unaligned 32-bit loads and a fast ntohl() is available.
68 * Otherwise fall back to byte loads and shifts which is portable,
69 * and is faster on architectures with memory alignment issues.
70 */
71
ee7dc310 72#if defined(__i386__) || defined(__x86_64__) || \
078e9bce 73 defined(_M_IX86) || defined(_M_X64) || \
ee7dc310
NP
74 defined(__ppc__) || defined(__ppc64__) || \
75 defined(__powerpc__) || defined(__powerpc64__) || \
76 defined(__s390__) || defined(__s390x__)
660231aa
NP
77
78#define get_be32(p) ntohl(*(unsigned int *)(p))
79#define put_be32(p, v) do { *(unsigned int *)(p) = htonl(v); } while (0)
80
81#else
82
83#define get_be32(p) ( \
84 (*((unsigned char *)(p) + 0) << 24) | \
85 (*((unsigned char *)(p) + 1) << 16) | \
86 (*((unsigned char *)(p) + 2) << 8) | \
87 (*((unsigned char *)(p) + 3) << 0) )
88#define put_be32(p, v) do { \
89 unsigned int __v = (v); \
90 *((unsigned char *)(p) + 0) = __v >> 24; \
91 *((unsigned char *)(p) + 1) = __v >> 16; \
92 *((unsigned char *)(p) + 2) = __v >> 8; \
93 *((unsigned char *)(p) + 3) = __v >> 0; } while (0)
94
95#endif
96
dc52fd29
NP
97/* This "rolls" over the 512-bit array */
98#define W(x) (array[(x)&15])
99
ab14c823
LT
100/*
101 * Where do we get the source from? The first 16 iterations get it from
102 * the input data, the next mix it from the 512-bit array.
103 */
23119ffb
JN
104#define SHA_SRC(t) get_be32((unsigned char *) block + (t)*4)
105#define SHA_MIX(t) SHA_ROL(W((t)+13) ^ W((t)+8) ^ W((t)+2) ^ W(t), 1);
ab14c823 106
30d12d4c 107#define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \
66c9c6c0
LT
108 unsigned int TEMP = input(t); setW(t, TEMP); \
109 E += TEMP + SHA_ROL(A,5) + (fn) + (constant); \
110 B = SHA_ROR(B, 2); } while (0)
ab14c823 111
30d12d4c
LT
112#define T_0_15(t, A, B, C, D, E) SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
113#define T_16_19(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
114#define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E )
115#define T_40_59(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, ((B&C)+(D&(B^C))) , 0x8f1bbcdc, A, B, C, D, E )
116#define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0xca62c1d6, A, B, C, D, E )
ab14c823 117
5f6a1125 118static void blk_SHA1_Block(blk_SHA_CTX *ctx, const void *block)
d7c208a9 119{
30d12d4c 120 unsigned int A,B,C,D,E;
7b5075fc 121 unsigned int array[16];
d7c208a9 122
d7c208a9
LT
123 A = ctx->H[0];
124 B = ctx->H[1];
125 C = ctx->H[2];
126 D = ctx->H[3];
127 E = ctx->H[4];
128
5f6a1125 129 /* Round 1 - iterations 0-16 take their input from 'block' */
30d12d4c
LT
130 T_0_15( 0, A, B, C, D, E);
131 T_0_15( 1, E, A, B, C, D);
132 T_0_15( 2, D, E, A, B, C);
133 T_0_15( 3, C, D, E, A, B);
134 T_0_15( 4, B, C, D, E, A);
135 T_0_15( 5, A, B, C, D, E);
136 T_0_15( 6, E, A, B, C, D);
137 T_0_15( 7, D, E, A, B, C);
138 T_0_15( 8, C, D, E, A, B);
139 T_0_15( 9, B, C, D, E, A);
140 T_0_15(10, A, B, C, D, E);
141 T_0_15(11, E, A, B, C, D);
142 T_0_15(12, D, E, A, B, C);
143 T_0_15(13, C, D, E, A, B);
144 T_0_15(14, B, C, D, E, A);
145 T_0_15(15, A, B, C, D, E);
139e3456 146
ab14c823 147 /* Round 1 - tail. Input from 512-bit mixing array */
30d12d4c
LT
148 T_16_19(16, E, A, B, C, D);
149 T_16_19(17, D, E, A, B, C);
150 T_16_19(18, C, D, E, A, B);
151 T_16_19(19, B, C, D, E, A);
d7c208a9 152
ab14c823 153 /* Round 2 */
30d12d4c
LT
154 T_20_39(20, A, B, C, D, E);
155 T_20_39(21, E, A, B, C, D);
156 T_20_39(22, D, E, A, B, C);
157 T_20_39(23, C, D, E, A, B);
158 T_20_39(24, B, C, D, E, A);
159 T_20_39(25, A, B, C, D, E);
160 T_20_39(26, E, A, B, C, D);
161 T_20_39(27, D, E, A, B, C);
162 T_20_39(28, C, D, E, A, B);
163 T_20_39(29, B, C, D, E, A);
164 T_20_39(30, A, B, C, D, E);
165 T_20_39(31, E, A, B, C, D);
166 T_20_39(32, D, E, A, B, C);
167 T_20_39(33, C, D, E, A, B);
168 T_20_39(34, B, C, D, E, A);
169 T_20_39(35, A, B, C, D, E);
170 T_20_39(36, E, A, B, C, D);
171 T_20_39(37, D, E, A, B, C);
172 T_20_39(38, C, D, E, A, B);
173 T_20_39(39, B, C, D, E, A);
d7c208a9 174
ab14c823 175 /* Round 3 */
30d12d4c
LT
176 T_40_59(40, A, B, C, D, E);
177 T_40_59(41, E, A, B, C, D);
178 T_40_59(42, D, E, A, B, C);
179 T_40_59(43, C, D, E, A, B);
180 T_40_59(44, B, C, D, E, A);
181 T_40_59(45, A, B, C, D, E);
182 T_40_59(46, E, A, B, C, D);
183 T_40_59(47, D, E, A, B, C);
184 T_40_59(48, C, D, E, A, B);
185 T_40_59(49, B, C, D, E, A);
186 T_40_59(50, A, B, C, D, E);
187 T_40_59(51, E, A, B, C, D);
188 T_40_59(52, D, E, A, B, C);
189 T_40_59(53, C, D, E, A, B);
190 T_40_59(54, B, C, D, E, A);
191 T_40_59(55, A, B, C, D, E);
192 T_40_59(56, E, A, B, C, D);
193 T_40_59(57, D, E, A, B, C);
194 T_40_59(58, C, D, E, A, B);
195 T_40_59(59, B, C, D, E, A);
d7c208a9 196
ab14c823 197 /* Round 4 */
30d12d4c
LT
198 T_60_79(60, A, B, C, D, E);
199 T_60_79(61, E, A, B, C, D);
200 T_60_79(62, D, E, A, B, C);
201 T_60_79(63, C, D, E, A, B);
202 T_60_79(64, B, C, D, E, A);
203 T_60_79(65, A, B, C, D, E);
204 T_60_79(66, E, A, B, C, D);
205 T_60_79(67, D, E, A, B, C);
206 T_60_79(68, C, D, E, A, B);
207 T_60_79(69, B, C, D, E, A);
208 T_60_79(70, A, B, C, D, E);
209 T_60_79(71, E, A, B, C, D);
210 T_60_79(72, D, E, A, B, C);
211 T_60_79(73, C, D, E, A, B);
212 T_60_79(74, B, C, D, E, A);
213 T_60_79(75, A, B, C, D, E);
214 T_60_79(76, E, A, B, C, D);
215 T_60_79(77, D, E, A, B, C);
216 T_60_79(78, C, D, E, A, B);
217 T_60_79(79, B, C, D, E, A);
d7c208a9
LT
218
219 ctx->H[0] += A;
220 ctx->H[1] += B;
221 ctx->H[2] += C;
222 ctx->H[3] += D;
223 ctx->H[4] += E;
224}
30ba0de7
NP
225
226void blk_SHA1_Init(blk_SHA_CTX *ctx)
227{
228 ctx->size = 0;
229
230 /* Initialize H with the magic constants (see FIPS180 for constants) */
231 ctx->H[0] = 0x67452301;
232 ctx->H[1] = 0xefcdab89;
233 ctx->H[2] = 0x98badcfe;
234 ctx->H[3] = 0x10325476;
235 ctx->H[4] = 0xc3d2e1f0;
236}
237
238void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *data, unsigned long len)
239{
9eafa120 240 unsigned int lenW = ctx->size & 63;
30ba0de7
NP
241
242 ctx->size += len;
243
244 /* Read the data into W and process blocks as they get full */
245 if (lenW) {
9eafa120 246 unsigned int left = 64 - lenW;
30ba0de7
NP
247 if (len < left)
248 left = len;
249 memcpy(lenW + (char *)ctx->W, data, left);
250 lenW = (lenW + left) & 63;
251 len -= left;
a1221857 252 data = ((const char *)data + left);
30ba0de7
NP
253 if (lenW)
254 return;
255 blk_SHA1_Block(ctx, ctx->W);
256 }
257 while (len >= 64) {
258 blk_SHA1_Block(ctx, data);
a1221857 259 data = ((const char *)data + 64);
30ba0de7
NP
260 len -= 64;
261 }
262 if (len)
263 memcpy(ctx->W, data, len);
264}
265
266void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx)
267{
268 static const unsigned char pad[64] = { 0x80 };
269 unsigned int padlen[2];
270 int i;
271
272 /* Pad with a binary 1 (ie 0x80), then zeroes, then length */
9eafa120
RJ
273 padlen[0] = htonl((uint32_t)(ctx->size >> 29));
274 padlen[1] = htonl((uint32_t)(ctx->size << 3));
30ba0de7
NP
275
276 i = ctx->size & 63;
277 blk_SHA1_Update(ctx, pad, 1+ (63 & (55 - i)));
278 blk_SHA1_Update(ctx, padlen, 8);
279
280 /* Output hash */
281 for (i = 0; i < 5; i++)
660231aa 282 put_be32(hashout + i*4, ctx->H[i]);
30ba0de7 283}