70186711f
Denys Vlasenko
2010-10-16
Subject
libbb/md5: code shrink
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include/libbb.h+0 -1
| @@ -1540,7 +1540,6 @@ typedef struct md5_ctx_t { | |
| uint32_t C; | |
| uint32_t D; | |
| uint64_t total; | |
| - | uint32_t buflen; |
| char buffer[128]; | |
| } md5_ctx_t; | |
| #else | |
libbb/md5.c+26 -22
| @@ -1,7 +1,7 @@ | |
| /* vi: set sw=4 ts=4: */ | |
| /* | |
| - | * md5.c - Compute MD5 checksum of strings according to the |
| - | * definition of MD5 in RFC 1321 from April 1992. |
| + | * Compute MD5 checksum of strings according to the |
| + | * definition of MD5 in RFC 1321 from April 1992. |
| * | |
| * Written by Ulrich Drepper <[email protected]>, 1995. | |
| * | |
| @@ -34,7 +34,6 @@ void FAST_FUNC md5_begin(md5_ctx_t *ctx) | |
| ctx->C = 0x98badcfe; | |
| ctx->D = 0x10325476; | |
| ctx->total = 0; | |
| - | ctx->buflen = 0; |
| } | |
| /* These are the four functions used in the four steps of the MD5 algorithm | |
| @@ -355,35 +354,39 @@ static void md5_hash_block(const void *buffer, md5_ctx_t *ctx) | |
| ctx->D = D; | |
| } | |
| + | /* The size of filled part of ctx->buffer: */ |
| + | #define BUFLEN(ctx) (((unsigned)ctx->total) & 63) |
| + | |
| /* Feed data through a temporary buffer to call md5_hash_aligned_block() | |
| * with chunks of data that are 4-byte aligned and a multiple of 64 bytes. | |
| * This function's internal buffer remembers previous data until it has 64 | |
| * bytes worth to pass on. Call md5_end() to flush this buffer. */ | |
| void FAST_FUNC md5_hash(const void *buffer, size_t len, md5_ctx_t *ctx) | |
| { | |
| - | char *buf = (char *)buffer; |
| + | const char *buf = buffer; |
| + | unsigned buflen = BUFLEN(ctx); |
| - | /* RFC 1321 specifies the possible length of the file up to 2^64 bits, |
| + | /* RFC 1321 specifies the possible length of the file up to 2^64 bits. |
| * Here we only track the number of bytes. */ | |
| ctx->total += len; | |
| /* Process all input. */ | |
| - | while (len) { |
| - | unsigned i = 64 - ctx->buflen; |
| - | |
| - | /* Copy data into aligned buffer. */ |
| + | while (1) { |
| + | unsigned i = 64 - buflen; |
| if (i > len) | |
| i = len; | |
| - | memcpy(ctx->buffer + ctx->buflen, buf, i); |
| + | /* Copy data into aligned buffer. */ |
| + | memcpy(ctx->buffer + buflen, buf, i); |
| len -= i; | |
| - | ctx->buflen += i; |
| buf += i; | |
| - | |
| - | /* When buffer fills up, process it. */ |
| - | if (ctx->buflen == 64) { |
| - | md5_hash_block(ctx->buffer, ctx); |
| - | ctx->buflen = 0; |
| - | } |
| + | buflen += i; |
| + | /* clever way to do "if (buflen != 64) break; ... ; buflen = 0;" */ |
| + | buflen -= 64; |
| + | if (buflen != 0) |
| + | break; |
| + | /* Buffer is filled up, process it. */ |
| + | md5_hash_block(ctx->buffer, ctx); |
| + | /*buflen = 0; - already is */ |
| } | |
| } | |
| @@ -396,18 +399,19 @@ void FAST_FUNC md5_end(void *resbuf, md5_ctx_t *ctx) | |
| { | |
| uint64_t total; | |
| char *buf = ctx->buffer; | |
| - | int i; |
| + | unsigned i; |
| + | unsigned buflen = BUFLEN(ctx); |
| /* Pad data to block size. */ | |
| - | buf[ctx->buflen++] = 0x80; |
| - | memset(buf + ctx->buflen, 0, 128 - ctx->buflen); |
| + | buf[buflen++] = 0x80; |
| + | memset(buf + buflen, 0, 128 - buflen); |
| /* Put the 64-bit file length, expressed in *bits*, | |
| * at the end of the buffer. | |
| */ | |
| + | /* clever way to do "if (buflen > 56) buf += 64": */ |
| + | buf += ((buflen + 7) & 64); |
| total = ctx->total << 3; | |
| - | if (ctx->buflen > 56) |
| - | buf += 64; |
| for (i = 0; i < 8; i++) { | |
| buf[56 + i] = total; | |
| total >>= 8; | |