[git commit master 1/1] md5: code shrink

[Denys Vlasenko]

commit: http://git.busybox.net/busybox/commit/?id=36ab585f68295487a0973bde86bcb0ab7577a8ff
branch: http://git.busybox.net/busybox/commit/?id=refs/heads/master

function                                             old     new   delta
md5_end                                              125     104     -21

Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
 libbb/md5.c  |   37 ++++++++++++++++++-------------------
 libbb/sha1.c |   18 +++++++-----------
 2 files changed, 25 insertions(+), 30 deletions(-)

diff --git a/libbb/md5.c b/libbb/md5.c
index cf3825a..a1f0a92 100644
--- a/libbb/md5.c
+++ b/libbb/md5.c
@@ -418,31 +418,30 @@ void FAST_FUNC md5_hash(md5_ctx_t *ctx, const void *buffer, size_t len)
  */
 void FAST_FUNC md5_end(md5_ctx_t *ctx, void *resbuf)
 {
-	uint64_t total;
-	unsigned i;
 	unsigned bufpos = BUFPOS(ctx);
-
-	/* Pad data to block size.  */
+	/* Pad the buffer to the next 64-byte boundary with 0x80,0,0,0... */
 	ctx->buffer[bufpos++] = 0x80;
-	memset(ctx->buffer + bufpos, 0, 64 - bufpos);
 
-	if (bufpos > 56) {
+	/* This loop iterates either once or twice, no more, no less */
+	while (1) {
+		unsigned remaining = 64 - bufpos;
+		memset(ctx->buffer + bufpos, 0, remaining);
+		/* Do we have enough space for the length count? */
+		if (remaining >= 8) {
+			/* Store the 64-bit counter of bits in the buffer in BE format */
+			uint64_t t = ctx->total << 3;
+			unsigned i;
+			for (i = 0; i < 8; i++) {
+				ctx->buffer[56 + i] = t;
+				t >>= 8;
+			}
+		}
 		md5_hash_block(ctx);
-		memset(ctx->buffer, 0, 64);
-	}
-
-	/* Put the 64-bit file length, expressed in *bits*,
-	 * at the end of the buffer.
-	 */
-	total = ctx->total << 3;
-	for (i = 0; i < 8; i++) {
-		ctx->buffer[56 + i] = total;
-		total >>= 8;
+		if (remaining >= 8)
+			break;
+		bufpos = 0;
 	}
 
-	/* Process last bytes.  */
-	md5_hash_block(ctx);
-
 	/* The MD5 result is in little endian byte order.
 	 * We (ab)use the fact that A-D are consecutive in memory.
 	 */
diff --git a/libbb/sha1.c b/libbb/sha1.c
index 70efd58..3e61aff 100644
--- a/libbb/sha1.c
+++ b/libbb/sha1.c
@@ -462,17 +462,15 @@ void FAST_FUNC sha512_hash(sha512_ctx_t *ctx, const void *buffer, size_t len)
 /* Used also for sha256 */
 void FAST_FUNC sha1_end(sha1_ctx_t *ctx, void *resbuf)
 {
-	unsigned pad, bufpos;
+	unsigned bufpos = ctx->total64 & 63;
 
-	bufpos = ctx->total64 & 63;
 	/* Pad the buffer to the next 64-byte boundary with 0x80,0,0,0... */
 	ctx->wbuffer[bufpos++] = 0x80;
 
 	/* This loop iterates either once or twice, no more, no less */
 	while (1) {
-		pad = 64 - bufpos;
+		unsigned pad = 64 - bufpos;
 		memset(ctx->wbuffer + bufpos, 0, pad);
-		bufpos = 0;
 		/* Do we have enough space for the length count? */
 		if (pad >= 8) {
 			/* Store the 64-bit counter of bits in the buffer in BE format */
@@ -484,6 +482,7 @@ void FAST_FUNC sha1_end(sha1_ctx_t *ctx, void *resbuf)
 		ctx->process_block(ctx);
 		if (pad >= 8)
 			break;
+		bufpos = 0;
 	}
 
 	bufpos = (ctx->process_block == sha1_process_block64) ? 5 : 8;
@@ -498,18 +497,14 @@ void FAST_FUNC sha1_end(sha1_ctx_t *ctx, void *resbuf)
 
 void FAST_FUNC sha512_end(sha512_ctx_t *ctx, void *resbuf)
 {
-	unsigned pad, bufpos;
+	unsigned bufpos = ctx->total64[0] & 127;
 
-	bufpos = ctx->total64[0] & 127;
-	/* Pad the buffer to the next 128-byte boundary with 0x80,0,0,0...
-	 * (FIPS 180-2:5.1.2)
-	 */
+	/* Pad the buffer to the next 128-byte boundary with 0x80,0,0,0... */
 	ctx->wbuffer[bufpos++] = 0x80;
 
 	while (1) {
-		pad = 128 - bufpos;
+		unsigned pad = 128 - bufpos;
 		memset(ctx->wbuffer + bufpos, 0, pad);
-		bufpos = 0;
 		if (pad >= 16) {
 			/* Store the 128-bit counter of bits in the buffer in BE format */
 			uint64_t t;
@@ -523,6 +518,7 @@ void FAST_FUNC sha512_end(sha512_ctx_t *ctx, void *resbuf)
 		sha512_process_block128(ctx);
 		if (pad >= 16)
 			break;
+		bufpos = 0;
 	}
 
 	if (BB_LITTLE_ENDIAN) {
-- 
1.7.1