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sha1: use Rob's code, it's smaller and faster

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function                                             old     new   delta
static.rconsts                                         -      16     +16
sha1_process_block64                                 460     298    -162
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/1 up/down: 16/-162)          Total: -146 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2010-10-24 19:27:30 +02:00
parent 4b63e16d20
commit f4c93ab304
1 changed files with 49 additions and 52 deletions
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101
libbb/hash_md5_sha.c
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@@ -473,20 +473,13 @@ void FAST_FUNC md5_end(md5_ctx_t *ctx, void *resbuf)
/*
* Based on shasum from http://www.netsw.org/crypto/hash/
* Majorly hacked up to use Dr Brian Gladman's sha1 code
* SHA1 part is:
* Copyright 2007 Rob Landley <rob@landley.net>
*
* Copyright (C) 2002 Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK.
* Copyright (C) 2003 Glenn L. McGrath
* Copyright (C) 2003 Erik Andersen
* Based on the public domain SHA-1 in C by Steve Reid <steve@edmweb.com>
* from http://www.mirrors.wiretapped.net/security/cryptography/hashes/sha1/
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*
* ---------------------------------------------------------------------------
* Issue Date: 10/11/2002
*
* This is a byte oriented version of SHA1 that operates on arrays of bytes
* stored in memory. It runs at 22 cycles per byte on a Pentium P4 processor
* Licensed under GPLv2, see file LICENSE in this source tree.
*
* ---------------------------------------------------------------------------
*
@@ -503,16 +496,18 @@ void FAST_FUNC md5_end(md5_ctx_t *ctx, void *resbuf)
static void FAST_FUNC sha1_process_block64(sha1_ctx_t *ctx)
{
unsigned t;
uint32_t W[80], a, b, c, d, e;
const uint32_t *words = (uint32_t*) ctx->wbuffer;
static const uint32_t rconsts[] = {
0x5A827999, 0x6ED9EBA1, 0x8F1BBCDC, 0xCA62C1D6
};
int i, j;
int cnt;
uint32_t W[16+16];
uint32_t a, b, c, d, e;
for (t = 0; t < 16; ++t)
W[t] = SWAP_BE32(words[t]);
for (/*t = 16*/; t < 80; ++t) {
uint32_t T = W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16];
W[t] = rotl32(T, 1);
}
/* On-stack work buffer frees up one register in the main loop
* which otherwise will be needed to hold ctx pointer */
for (i = 0; i < 16; i++)
W[i] = W[i+16] = SWAP_BE32(((uint32_t*)ctx->wbuffer)[i]);
a = ctx->hash[0];
b = ctx->hash[1];
@@ -520,39 +515,41 @@ static void FAST_FUNC sha1_process_block64(sha1_ctx_t *ctx)
d = ctx->hash[3];
e = ctx->hash[4];
#undef ch
#undef parity
#undef maj
#undef rnd
#define ch(x,y,z) ((z) ^ ((x) & ((y) ^ (z))))
#define parity(x,y,z) ((x) ^ (y) ^ (z))
#define maj(x,y,z) (((x) & (y)) | ((z) & ((x) | (y))))
/* A normal version as set out in the FIPS. */
#define rnd(f,k) \
do { \
uint32_t T = a; \
a = rotl32(a, 5) + f(b, c, d) + e + k + W[t]; \
e = d; \
d = c; \
c = rotl32(b, 30); \
b = T; \
} while (0)
/* 4 rounds of 20 operations each */
cnt = 0;
for (i = 0; i < 4; i++) {
j = 19;
do {
uint32_t work;
for (t = 0; t < 20; ++t)
rnd(ch, 0x5a827999);
work = c ^ d;
if (i == 0) {
work = (work & b) ^ d;
if (j <= 3)
goto ge16;
/* Used to do SWAP_BE32 here, but this
* requires ctx (see comment above) */
work += W[cnt];
} else {
if (i == 2)
work = ((b | c) & d) | (b & c);
else /* i = 1 or 3 */
work ^= b;
ge16:
W[cnt] = W[cnt+16] = rotl32(W[cnt+13] ^ W[cnt+8] ^ W[cnt+2] ^ W[cnt], 1);
work += W[cnt];
}
work = e + work + rotl32(a, 5) + rconsts[i];
for (/*t = 20*/; t < 40; ++t)
rnd(parity, 0x6ed9eba1);
for (/*t = 40*/; t < 60; ++t)
rnd(maj, 0x8f1bbcdc);
for (/*t = 60*/; t < 80; ++t)
rnd(parity, 0xca62c1d6);
#undef ch
#undef parity
#undef maj
#undef rnd
/* Rotate by one for next time */
e = d;
d = c;
c = /* b = */ rotl32(b, 30);
b = a;
a = work;
cnt = (cnt + 1) & 15;
} while (--j >= 0);
}
ctx->hash[0] += a;
ctx->hash[1] += b;