thodg/libgit2/src/block-sha1/sha1.c
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Hash : 5dddf7c8
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Date : 2010-04-14T20:41:57
Add block-sha1 in favour of the mozilla routines Since block-sha1 from git.git has such excellent performance, we can also get rid of the openssl dependency. It's rather simple to add it back later as an optional extra, but we really needn't bother to pull in the entire ssl library and have to deal with linking issues now that we have the portable and, performance-wise, truly excellent block-sha1 code to fall back on. Since this requires a slight revamp of the build rules anyway, we take the opportunity to fix including EXTRA_OBJS in the final build as well. The block-sha1 code was originally implemented for git.git by Linus Torvalds <torvalds@linux-foundation.org> and was later polished by Nicolas Pitre <nico@cam.org>. Signed-off-by: Andreas Ericsson <ae@op5.se>
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src/block-sha1/sha1.c
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/* * SHA1 routine optimized to do word accesses rather than byte accesses, * and to avoid unnecessary copies into the context array. * * This was initially based on the Mozilla SHA1 implementation, although * none of the original Mozilla code remains. */ #include "common.h" #include "sha1.h" #if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)) /* * Force usage of rol or ror by selecting the one with the smaller constant. * It _can_ generate slightly smaller code (a constant of 1 is special), but * perhaps more importantly it's possibly faster on any uarch that does a * rotate with a loop. */ #define SHA_ASM(op, x, n) ({ unsigned int __res; __asm__(op " %1,%0":"=r" (__res):"i" (n), "0" (x)); __res; }) #define SHA_ROL(x,n) SHA_ASM("rol", x, n) #define SHA_ROR(x,n) SHA_ASM("ror", x, n) #else #define SHA_ROT(X,l,r) (((X) << (l)) | ((X) >> (r))) #define SHA_ROL(X,n) SHA_ROT(X,n,32-(n)) #define SHA_ROR(X,n) SHA_ROT(X,32-(n),n) #endif /* * If you have 32 registers or more, the compiler can (and should) * try to change the array[] accesses into registers. However, on * machines with less than ~25 registers, that won't really work, * and at least gcc will make an unholy mess of it. * * So to avoid that mess which just slows things down, we force * the stores to memory to actually happen (we might be better off * with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as * suggested by Artur Skawina - that will also make gcc unable to * try to do the silly "optimize away loads" part because it won't * see what the value will be). * * Ben Herrenschmidt reports that on PPC, the C version comes close * to the optimized asm with this (ie on PPC you don't want that * 'volatile', since there are lots of registers). * * On ARM we get the best code generation by forcing a full memory barrier * between each SHA_ROUND, otherwise gcc happily get wild with spilling and * the stack frame size simply explode and performance goes down the drain. */ #if defined(__i386__) || defined(__x86_64__) #define setW(x, val) (*(volatile unsigned int *)&W(x) = (val)) #elif defined(__GNUC__) && defined(__arm__) #define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0) #else #define setW(x, val) (W(x) = (val)) #endif /* * Performance might be improved if the CPU architecture is OK with * unaligned 32-bit loads and a fast ntohl() is available. * Otherwise fall back to byte loads and shifts which is portable, * and is faster on architectures with memory alignment issues. */ #if defined(__i386__) || defined(__x86_64__) || \ defined(__ppc__) || defined(__ppc64__) || \ defined(__powerpc__) || defined(__powerpc64__) || \ defined(__s390__) || defined(__s390x__) #define get_be32(p) ntohl(*(unsigned int *)(p)) #define put_be32(p, v) do { *(unsigned int *)(p) = htonl(v); } while (0) #else #define get_be32(p) ( \ (*((unsigned char *)(p) + 0) << 24) | \ (*((unsigned char *)(p) + 1) << 16) | \ (*((unsigned char *)(p) + 2) << 8) | \ (*((unsigned char *)(p) + 3) << 0) ) #define put_be32(p, v) do { \ unsigned int __v = (v); \ *((unsigned char *)(p) + 0) = __v >> 24; \ *((unsigned char *)(p) + 1) = __v >> 16; \ *((unsigned char *)(p) + 2) = __v >> 8; \ *((unsigned char *)(p) + 3) = __v >> 0; } while (0) #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) get_be32(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, A, B, C, D, E) do { \ unsigned int TEMP = input(t); setW(t, TEMP); \ E += TEMP + SHA_ROL(A,5) + (fn) + (constant); \ B = SHA_ROR(B, 2); } while (0) #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 ) #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 ) #define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E ) #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 ) #define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0xca62c1d6, A, B, C, D, E ) static void blk_SHA1_Block(blk_SHA_CTX *ctx, const unsigned int *data) { unsigned int A,B,C,D,E; unsigned int array[16]; A = ctx->H[0]; B = ctx->H[1]; C = ctx->H[2]; D = ctx->H[3]; E = ctx->H[4]; /* Round 1 - iterations 0-16 take their input from 'data' */ T_0_15( 0, A, B, C, D, E); T_0_15( 1, E, A, B, C, D); T_0_15( 2, D, E, A, B, C); T_0_15( 3, C, D, E, A, B); T_0_15( 4, B, C, D, E, A); T_0_15( 5, A, B, C, D, E); T_0_15( 6, E, A, B, C, D); T_0_15( 7, D, E, A, B, C); T_0_15( 8, C, D, E, A, B); T_0_15( 9, B, C, D, E, A); T_0_15(10, A, B, C, D, E); T_0_15(11, E, A, B, C, D); T_0_15(12, D, E, A, B, C); T_0_15(13, C, D, E, A, B); T_0_15(14, B, C, D, E, A); T_0_15(15, A, B, C, D, E); /* Round 1 - tail. Input from 512-bit mixing array */ T_16_19(16, E, A, B, C, D); T_16_19(17, D, E, A, B, C); T_16_19(18, C, D, E, A, B); T_16_19(19, B, C, D, E, A); /* Round 2 */ T_20_39(20, A, B, C, D, E); T_20_39(21, E, A, B, C, D); T_20_39(22, D, E, A, B, C); T_20_39(23, C, D, E, A, B); T_20_39(24, B, C, D, E, A); T_20_39(25, A, B, C, D, E); T_20_39(26, E, A, B, C, D); T_20_39(27, D, E, A, B, C); T_20_39(28, C, D, E, A, B); T_20_39(29, B, C, D, E, A); T_20_39(30, A, B, C, D, E); T_20_39(31, E, A, B, C, D); T_20_39(32, D, E, A, B, C); T_20_39(33, C, D, E, A, B); T_20_39(34, B, C, D, E, A); T_20_39(35, A, B, C, D, E); T_20_39(36, E, A, B, C, D); T_20_39(37, D, E, A, B, C); T_20_39(38, C, D, E, A, B); T_20_39(39, B, C, D, E, A); /* Round 3 */ T_40_59(40, A, B, C, D, E); T_40_59(41, E, A, B, C, D); T_40_59(42, D, E, A, B, C); T_40_59(43, C, D, E, A, B); T_40_59(44, B, C, D, E, A); T_40_59(45, A, B, C, D, E); T_40_59(46, E, A, B, C, D); T_40_59(47, D, E, A, B, C); T_40_59(48, C, D, E, A, B); T_40_59(49, B, C, D, E, A); T_40_59(50, A, B, C, D, E); T_40_59(51, E, A, B, C, D); T_40_59(52, D, E, A, B, C); T_40_59(53, C, D, E, A, B); T_40_59(54, B, C, D, E, A); T_40_59(55, A, B, C, D, E); T_40_59(56, E, A, B, C, D); T_40_59(57, D, E, A, B, C); T_40_59(58, C, D, E, A, B); T_40_59(59, B, C, D, E, A); /* Round 4 */ T_60_79(60, A, B, C, D, E); T_60_79(61, E, A, B, C, D); T_60_79(62, D, E, A, B, C); T_60_79(63, C, D, E, A, B); T_60_79(64, B, C, D, E, A); T_60_79(65, A, B, C, D, E); T_60_79(66, E, A, B, C, D); T_60_79(67, D, E, A, B, C); T_60_79(68, C, D, E, A, B); T_60_79(69, B, C, D, E, A); T_60_79(70, A, B, C, D, E); T_60_79(71, E, A, B, C, D); T_60_79(72, D, E, A, B, C); T_60_79(73, C, D, E, A, B); T_60_79(74, B, C, D, E, A); T_60_79(75, A, B, C, D, E); T_60_79(76, E, A, B, C, D); T_60_79(77, D, E, A, B, C); T_60_79(78, C, D, E, A, B); T_60_79(79, B, C, D, E, A); ctx->H[0] += A; ctx->H[1] += B; ctx->H[2] += C; ctx->H[3] += D; ctx->H[4] += E; } void blk_SHA1_Init(blk_SHA_CTX *ctx) { ctx->size = 0; /* Initialize H with the magic constants (see FIPS180 for constants) */ ctx->H[0] = 0x67452301; ctx->H[1] = 0xefcdab89; ctx->H[2] = 0x98badcfe; ctx->H[3] = 0x10325476; ctx->H[4] = 0xc3d2e1f0; } void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *data, unsigned long len) { int lenW = ctx->size & 63; ctx->size += len; /* Read the data into W and process blocks as they get full */ if (lenW) { int left = 64 - lenW; if (len < left) left = len; memcpy(lenW + (char *)ctx->W, data, left); lenW = (lenW + left) & 63; len -= left; data = ((const char *)data + left); if (lenW) return; blk_SHA1_Block(ctx, ctx->W); } while (len >= 64) { blk_SHA1_Block(ctx, data); data = ((const char *)data + 64); len -= 64; } if (len) memcpy(ctx->W, data, len); } void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx) { static const unsigned char pad[64] = { 0x80 }; unsigned int padlen[2]; int i; /* Pad with a binary 1 (ie 0x80), then zeroes, then length */ padlen[0] = htonl(ctx->size >> 29); padlen[1] = htonl(ctx->size << 3); i = ctx->size & 63; blk_SHA1_Update(ctx, pad, 1+ (63 & (55 - i))); blk_SHA1_Update(ctx, padlen, 8); /* Output hash */ for (i = 0; i < 5; i++) put_be32(hashout + i*4, ctx->H[i]); }