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shrink sha hashing

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function                                             old     new   delta
sha512_hash                                          262     281     +19
sha512_end                                           204     221     +17
sha1_hash                                            128     113     -15
static.mask                                           16       -     -16
static.bits                                           16       -     -16
sha1_end                                             160     136     -24
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 2/2 up/down: 36/-71)            Total: -35 bytes
This commit is contained in:
Denis Vlasenko 2009-03-12 15:39:11 +00:00
parent 4abaec50a2
commit 6a5d9faa29
2 changed files with 32 additions and 47 deletions
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2
libbb/pw_encrypt_sha.c
View File

@ -20,7 +20,7 @@ sha_crypt(/*const*/ char *key_data, /*const*/ char *salt_data)
{
void (*sha_begin)(void *ctx) FAST_FUNC;
void (*sha_hash)(const void *buffer, size_t len, void *ctx) FAST_FUNC;
void* (*sha_end)(void *resbuf, void *ctx) FAST_FUNC;
void (*sha_end)(void *resbuf, void *ctx) FAST_FUNC;
int _32or64;
char *result, *resptr;

77
libbb/sha1.c
View File

@ -406,22 +406,21 @@ void FAST_FUNC sha512_begin(sha512_ctx_t *ctx)
/* hash_compile function as required. */
void FAST_FUNC sha1_hash(const void *buffer, size_t len, sha1_ctx_t *ctx)
{
uint32_t pos = (uint32_t) (ctx->total64 & SHA1_MASK);
uint32_t freeb = SHA1_BLOCK_SIZE - pos;
const unsigned char *sp = buffer;
unsigned wbuflen = ctx->total64 & SHA1_MASK;
unsigned add = SHA1_BLOCK_SIZE - wbuflen;
ctx->total64 += len;
while (len >= freeb) { /* transfer whole blocks while possible */
memcpy(((unsigned char *) ctx->wbuffer) + pos, sp, freeb);
sp += freeb;
len -= freeb;
freeb = SHA1_BLOCK_SIZE;
pos = 0;
while (len >= add) { /* transfer whole blocks while possible */
memcpy(((unsigned char *) ctx->wbuffer) + wbuflen, buffer, add);
buffer = (const char *)buffer + add;
len -= add;
add = SHA1_BLOCK_SIZE;
wbuflen = 0;
sha1_process_block64(ctx);
}
memcpy(((unsigned char *) ctx->wbuffer) + pos, sp, len);
memcpy(((unsigned char *) ctx->wbuffer) + wbuflen, buffer, len);
}
void FAST_FUNC sha256_hash(const void *buffer, size_t len, sha256_ctx_t *ctx)
@ -517,42 +516,24 @@ void FAST_FUNC sha512_hash(const void *buffer, size_t len, sha512_ctx_t *ctx)
void FAST_FUNC sha1_end(void *resbuf, sha1_ctx_t *ctx)
{
/* SHA1 Final padding and digest calculation */
#if BB_BIG_ENDIAN
static const uint32_t mask[4] = { 0x00000000, 0xff000000, 0xffff0000, 0xffffff00 };
static const uint32_t bits[4] = { 0x80000000, 0x00800000, 0x00008000, 0x00000080 };
#else
static const uint32_t mask[4] = { 0x00000000, 0x000000ff, 0x0000ffff, 0x00ffffff };
static const uint32_t bits[4] = { 0x00000080, 0x00008000, 0x00800000, 0x80000000 };
#endif
unsigned i, wbuflen, pad;
uint8_t *hval = resbuf;
uint32_t i, cnt = (uint32_t) (ctx->total64 & SHA1_MASK);
/* Pad the buffer to the next 64-byte boundary with 0x80,0,0,0... */
wbuflen = ctx->total64 & SHA1_MASK;
((uint8_t *)ctx->wbuffer)[wbuflen++] = 0x80;
pad = SHA1_BLOCK_SIZE - wbuflen;
memset(((uint8_t *)ctx->wbuffer) + wbuflen, 0, pad);
/* mask out the rest of any partial 32-bit word and then set */
/* the next byte to 0x80. On big-endian machines any bytes in */
/* the buffer will be at the top end of 32 bit words, on little */
/* endian machines they will be at the bottom. Hence the AND */
/* and OR masks above are reversed for little endian systems */
ctx->wbuffer[cnt >> 2] =
(ctx->wbuffer[cnt >> 2] & mask[cnt & 3]) | bits[cnt & 3];
/* we need 9 or more empty positions, one for the padding byte */
/* (above) and eight for the length count. If there is not */
/* enough space pad and empty the buffer */
if (cnt > SHA1_BLOCK_SIZE - 9) {
if (cnt < 60)
ctx->wbuffer[15] = 0;
/* We need 1+8 or more empty positions, one for the padding byte
* (above) and eight for the length count.
* If there is not enough space, empty the buffer. */
if (pad < 8) {
sha1_process_block64(ctx);
cnt = 0;
} else /* compute a word index for the empty buffer positions */
cnt = (cnt >> 2) + 1;
memset(ctx->wbuffer, 0, SHA1_BLOCK_SIZE - 8);
((uint8_t *)ctx->wbuffer)[0] = 0x80;
}
while (cnt < 14) /* and zero pad all but last two positions */
ctx->wbuffer[cnt++] = 0;
/* assemble the 64-bit counter of bits in the buffer in BE */
/* format */
/* Store the 64-bit counter of bits in the buffer in BE format */
{
uint64_t t = ctx->total64 << 3;
t = hton64(t);
@ -562,10 +543,14 @@ void FAST_FUNC sha1_end(void *resbuf, sha1_ctx_t *ctx)
sha1_process_block64(ctx);
/* extract the hash value as bytes in case the hash buffer is */
/* misaligned for 32-bit words */
for (i = 0; i < SHA1_DIGEST_SIZE; ++i)
hval[i] = (unsigned char) (ctx->hash[i >> 2] >> 8 * (~i & 3));
/* Extract the hash value as bytes in case resbuf is
* misaligned for 32-bit words */
for (i = 0; i < ARRAY_SIZE(ctx->hash); ++i) {
uint32_t t = ctx->hash[i];
t = ntohl(t); /* paranoia. this can be a macro */
move_to_unaligned32(resbuf, t); /* ditto */
resbuf = (char*)resbuf + 4;
}
}