mirror/git
1
0
Fork 0
mirror of https://github.com/git/git.git synced 2024-09-28 19:42:15 +02:00
Code

block-sha1: macroize the rounds a bit further

Browse Source 
Avoid repeating the shared parts of the different rounds by adding a
macro layer or two. It was already more cpp than C.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Linus Torvalds 2009-08-06 07:20:54 -07:00 committed by Junio C Hamano
parent 7b5075fcfb
commit ab14c823df
1 changed files with 26 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

56
block-sha1/sha1.c
View File

@ -94,6 +94,27 @@ void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx)
#endif
/* This "rolls" over the 512-bit array */
#define W(x) (array[(x)&15])
/*
* Where do we get the source from? The first 16 iterations get it from
* the input data, the next mix it from the 512-bit array.
*/
#define SHA_SRC(t) htonl(data[t])
#define SHA_MIX(t) SHA_ROL(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1)
#define SHA_ROUND(t, input, fn, constant) \
TEMP = input(t); W(t) = TEMP; \
TEMP += SHA_ROL(A,5) + (fn) + E + (constant); \
E = D; D = C; C = SHA_ROR(B, 2); B = A; A = TEMP
#define T_0_15(t) SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999 )
#define T_16_19(t) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999 )
#define T_20_39(t) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1 )
#define T_40_59(t) SHA_ROUND(t, SHA_MIX, ((B&C)|(D&(B|C))) , 0x8f1bbcdc )
#define T_60_79(t) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0xca62c1d6 )
static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data)
{
unsigned int A,B,C,D,E,TEMP;
@ -105,53 +126,28 @@ static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data)
D = ctx->H[3];
E = ctx->H[4];
#define T_0_15(t) \
TEMP = htonl(data[t]); array[t] = TEMP; \
TEMP += SHA_ROL(A,5) + (((C^D)&B)^D) + E + 0x5a827999; \
E = D; D = C; C = SHA_ROR(B, 2); B = A; A = TEMP; \
/* Round 1 - iterations 0-16 take their input from 'data' */
T_0_15( 0); T_0_15( 1); T_0_15( 2); T_0_15( 3); T_0_15( 4);
T_0_15( 5); T_0_15( 6); T_0_15( 7); T_0_15( 8); T_0_15( 9);
T_0_15(10); T_0_15(11); T_0_15(12); T_0_15(13); T_0_15(14);
T_0_15(15);
/* This "rolls" over the 512-bit array */
#define W(x) (array[(x)&15])
#define SHA_XOR(t) \
TEMP = SHA_ROL(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1); W(t) = TEMP;
#define T_16_19(t) \
SHA_XOR(t); \
TEMP += SHA_ROL(A,5) + (((C^D)&B)^D) + E + 0x5a827999; \
E = D; D = C; C = SHA_ROR(B, 2); B = A; A = TEMP; \
/* Round 1 - tail. Input from 512-bit mixing array */
T_16_19(16); T_16_19(17); T_16_19(18); T_16_19(19);
#define T_20_39(t) \
SHA_XOR(t); \
TEMP += SHA_ROL(A,5) + (B^C^D) + E + 0x6ed9eba1; \
E = D; D = C; C = SHA_ROR(B, 2); B = A; A = TEMP;
/* Round 2 */
T_20_39(20); T_20_39(21); T_20_39(22); T_20_39(23); T_20_39(24);
T_20_39(25); T_20_39(26); T_20_39(27); T_20_39(28); T_20_39(29);
T_20_39(30); T_20_39(31); T_20_39(32); T_20_39(33); T_20_39(34);
T_20_39(35); T_20_39(36); T_20_39(37); T_20_39(38); T_20_39(39);
#define T_40_59(t) \
SHA_XOR(t); \
TEMP += SHA_ROL(A,5) + ((B&C)|(D&(B|C))) + E + 0x8f1bbcdc; \
E = D; D = C; C = SHA_ROR(B, 2); B = A; A = TEMP;
/* Round 3 */
T_40_59(40); T_40_59(41); T_40_59(42); T_40_59(43); T_40_59(44);
T_40_59(45); T_40_59(46); T_40_59(47); T_40_59(48); T_40_59(49);
T_40_59(50); T_40_59(51); T_40_59(52); T_40_59(53); T_40_59(54);
T_40_59(55); T_40_59(56); T_40_59(57); T_40_59(58); T_40_59(59);
#define T_60_79(t) \
SHA_XOR(t); \
TEMP += SHA_ROL(A,5) + (B^C^D) + E + 0xca62c1d6; \
E = D; D = C; C = SHA_ROR(B, 2); B = A; A = TEMP;
/* Round 4 */
T_60_79(60); T_60_79(61); T_60_79(62); T_60_79(63); T_60_79(64);
T_60_79(65); T_60_79(66); T_60_79(67); T_60_79(68); T_60_79(69);
T_60_79(70); T_60_79(71); T_60_79(72); T_60_79(73); T_60_79(74);