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230 lines
6.6 KiB
230 lines
6.6 KiB
/* |
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* SHA1 routine optimized to do word accesses rather than byte accesses, |
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* and to avoid unnecessary copies into the context array. |
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* |
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* This was initially based on the Mozilla SHA1 implementation, although |
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* none of the original Mozilla code remains. |
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*/ |
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/* this is only to get definitions for memcpy(), ntohl() and htonl() */ |
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#include "../git-compat-util.h" |
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#include "sha1.h" |
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#define SHA_ROT(X,l,r) (((X) << (l)) | ((X) >> (r))) |
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#define SHA_ROL(X,n) SHA_ROT(X,n,32-(n)) |
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#define SHA_ROR(X,n) SHA_ROT(X,32-(n),n) |
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/* |
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* If you have 32 registers or more, the compiler can (and should) |
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* try to change the array[] accesses into registers. However, on |
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* machines with less than ~25 registers, that won't really work, |
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* and at least gcc will make an unholy mess of it. |
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* |
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* So to avoid that mess which just slows things down, we force |
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* the stores to memory to actually happen (we might be better off |
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* with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as |
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* suggested by Artur Skawina - that will also make gcc unable to |
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* try to do the silly "optimize away loads" part because it won't |
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* see what the value will be). |
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* |
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* On ARM we get the best code generation by forcing a full memory barrier |
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* between each SHA_ROUND, otherwise gcc happily get wild with spilling and |
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* the stack frame size simply explode and performance goes down the drain. |
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*/ |
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#if defined(__i386__) || defined(__x86_64__) |
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#define setW(x, val) (*(volatile unsigned int *)&W(x) = (val)) |
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#elif defined(__GNUC__) && defined(__arm__) |
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#define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0) |
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#else |
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#define setW(x, val) (W(x) = (val)) |
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#endif |
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/* This "rolls" over the 512-bit array */ |
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#define W(x) (array[(x)&15]) |
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/* |
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* Where do we get the source from? The first 16 iterations get it from |
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* the input data, the next mix it from the 512-bit array. |
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*/ |
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#define SHA_SRC(t) get_be32((unsigned char *) block + (t)*4) |
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#define SHA_MIX(t) SHA_ROL(W((t)+13) ^ W((t)+8) ^ W((t)+2) ^ W(t), 1) |
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#define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \ |
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unsigned int TEMP = input(t); setW(t, TEMP); \ |
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E += TEMP + SHA_ROL(A,5) + (fn) + (constant); \ |
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B = SHA_ROR(B, 2); } while (0) |
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#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 ) |
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#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 ) |
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#define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E ) |
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#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 ) |
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#define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0xca62c1d6, A, B, C, D, E ) |
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static void blk_SHA1_Block(blk_SHA_CTX *ctx, const void *block) |
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{ |
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unsigned int A,B,C,D,E; |
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unsigned int array[16]; |
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A = ctx->H[0]; |
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B = ctx->H[1]; |
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C = ctx->H[2]; |
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D = ctx->H[3]; |
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E = ctx->H[4]; |
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/* Round 1 - iterations 0-16 take their input from 'block' */ |
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T_0_15( 0, A, B, C, D, E); |
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T_0_15( 1, E, A, B, C, D); |
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T_0_15( 2, D, E, A, B, C); |
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T_0_15( 3, C, D, E, A, B); |
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T_0_15( 4, B, C, D, E, A); |
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T_0_15( 5, A, B, C, D, E); |
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T_0_15( 6, E, A, B, C, D); |
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T_0_15( 7, D, E, A, B, C); |
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T_0_15( 8, C, D, E, A, B); |
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T_0_15( 9, B, C, D, E, A); |
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T_0_15(10, A, B, C, D, E); |
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T_0_15(11, E, A, B, C, D); |
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T_0_15(12, D, E, A, B, C); |
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T_0_15(13, C, D, E, A, B); |
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T_0_15(14, B, C, D, E, A); |
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T_0_15(15, A, B, C, D, E); |
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/* Round 1 - tail. Input from 512-bit mixing array */ |
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T_16_19(16, E, A, B, C, D); |
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T_16_19(17, D, E, A, B, C); |
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T_16_19(18, C, D, E, A, B); |
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T_16_19(19, B, C, D, E, A); |
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/* Round 2 */ |
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T_20_39(20, A, B, C, D, E); |
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T_20_39(21, E, A, B, C, D); |
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T_20_39(22, D, E, A, B, C); |
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T_20_39(23, C, D, E, A, B); |
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T_20_39(24, B, C, D, E, A); |
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T_20_39(25, A, B, C, D, E); |
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T_20_39(26, E, A, B, C, D); |
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T_20_39(27, D, E, A, B, C); |
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T_20_39(28, C, D, E, A, B); |
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T_20_39(29, B, C, D, E, A); |
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T_20_39(30, A, B, C, D, E); |
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T_20_39(31, E, A, B, C, D); |
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T_20_39(32, D, E, A, B, C); |
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T_20_39(33, C, D, E, A, B); |
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T_20_39(34, B, C, D, E, A); |
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T_20_39(35, A, B, C, D, E); |
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T_20_39(36, E, A, B, C, D); |
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T_20_39(37, D, E, A, B, C); |
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T_20_39(38, C, D, E, A, B); |
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T_20_39(39, B, C, D, E, A); |
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/* Round 3 */ |
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T_40_59(40, A, B, C, D, E); |
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T_40_59(41, E, A, B, C, D); |
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T_40_59(42, D, E, A, B, C); |
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T_40_59(43, C, D, E, A, B); |
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T_40_59(44, B, C, D, E, A); |
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T_40_59(45, A, B, C, D, E); |
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T_40_59(46, E, A, B, C, D); |
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T_40_59(47, D, E, A, B, C); |
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T_40_59(48, C, D, E, A, B); |
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T_40_59(49, B, C, D, E, A); |
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T_40_59(50, A, B, C, D, E); |
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T_40_59(51, E, A, B, C, D); |
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T_40_59(52, D, E, A, B, C); |
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T_40_59(53, C, D, E, A, B); |
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T_40_59(54, B, C, D, E, A); |
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T_40_59(55, A, B, C, D, E); |
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T_40_59(56, E, A, B, C, D); |
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T_40_59(57, D, E, A, B, C); |
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T_40_59(58, C, D, E, A, B); |
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T_40_59(59, B, C, D, E, A); |
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/* Round 4 */ |
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T_60_79(60, A, B, C, D, E); |
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T_60_79(61, E, A, B, C, D); |
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T_60_79(62, D, E, A, B, C); |
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T_60_79(63, C, D, E, A, B); |
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T_60_79(64, B, C, D, E, A); |
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T_60_79(65, A, B, C, D, E); |
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T_60_79(66, E, A, B, C, D); |
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T_60_79(67, D, E, A, B, C); |
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T_60_79(68, C, D, E, A, B); |
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T_60_79(69, B, C, D, E, A); |
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T_60_79(70, A, B, C, D, E); |
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T_60_79(71, E, A, B, C, D); |
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T_60_79(72, D, E, A, B, C); |
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T_60_79(73, C, D, E, A, B); |
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T_60_79(74, B, C, D, E, A); |
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T_60_79(75, A, B, C, D, E); |
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T_60_79(76, E, A, B, C, D); |
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T_60_79(77, D, E, A, B, C); |
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T_60_79(78, C, D, E, A, B); |
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T_60_79(79, B, C, D, E, A); |
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ctx->H[0] += A; |
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ctx->H[1] += B; |
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ctx->H[2] += C; |
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ctx->H[3] += D; |
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ctx->H[4] += E; |
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} |
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void blk_SHA1_Init(blk_SHA_CTX *ctx) |
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{ |
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ctx->size = 0; |
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/* Initialize H with the magic constants (see FIPS180 for constants) */ |
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ctx->H[0] = 0x67452301; |
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ctx->H[1] = 0xefcdab89; |
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ctx->H[2] = 0x98badcfe; |
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ctx->H[3] = 0x10325476; |
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ctx->H[4] = 0xc3d2e1f0; |
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} |
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void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *data, size_t len) |
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{ |
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unsigned int lenW = ctx->size & 63; |
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ctx->size += len; |
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/* Read the data into W and process blocks as they get full */ |
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if (lenW) { |
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unsigned int left = 64 - lenW; |
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if (len < left) |
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left = len; |
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memcpy(lenW + (char *)ctx->W, data, left); |
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lenW = (lenW + left) & 63; |
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len -= left; |
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data = ((const char *)data + left); |
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if (lenW) |
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return; |
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blk_SHA1_Block(ctx, ctx->W); |
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} |
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while (len >= 64) { |
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blk_SHA1_Block(ctx, data); |
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data = ((const char *)data + 64); |
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len -= 64; |
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} |
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if (len) |
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memcpy(ctx->W, data, len); |
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} |
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void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx) |
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{ |
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static const unsigned char pad[64] = { 0x80 }; |
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unsigned int padlen[2]; |
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int i; |
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/* Pad with a binary 1 (ie 0x80), then zeroes, then length */ |
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padlen[0] = htonl((uint32_t)(ctx->size >> 29)); |
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padlen[1] = htonl((uint32_t)(ctx->size << 3)); |
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i = ctx->size & 63; |
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blk_SHA1_Update(ctx, pad, 1 + (63 & (55 - i))); |
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blk_SHA1_Update(ctx, padlen, 8); |
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/* Output hash */ |
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for (i = 0; i < 5; i++) |
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put_be32(hashout + i * 4, ctx->H[i]); |
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}
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