[CRYPTO] sha1: Avoid useless memcpy()

The current code unconditionally copy the first block for every call to
sha1_update().  This can be avoided if there is no pending partial block.
This is always the case on the first call to sha1_update() (if the length
is >= 64 of course.

Furthermore, temp does need to be called if sha_transform is never invoked.
Also consolidate the sha_transform calls into one to reduce code size.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/sha1.c b/crypto/sha1.c
index c686e78..292dcc1 100644 (file)
--- a/crypto/sha1.c
+++ b/crypto/sha1.c
@@ -50,22 +50,31 @@ static void sha1_update(void *ctx, const u8 *data, unsigned int len)
 {
        struct sha1_ctx *sctx = ctx;
        unsigned int i, j;
-       u32 temp[SHA_WORKSPACE_WORDS];
+       const u8 *src;
 
        j = (sctx->count >> 3) & 0x3f;
        sctx->count += len << 3;
+       i = 0;
+       src = data;
 
        if ((j + len) > 63) {
-               memcpy(&sctx->buffer[j], data, (i = 64-j));
-               sha_transform(sctx->state, sctx->buffer, temp);
-               for ( ; i + 63 < len; i += 64) {
-                       sha_transform(sctx->state, &data[i], temp);
+               u32 temp[SHA_WORKSPACE_WORDS];
+
+               if (j) {
+                       memcpy(&sctx->buffer[j], data, (i = 64-j));
+                       src = sctx->buffer;
                }
+
+               do {
+                       sha_transform(sctx->state, src, temp);
+                       i += 64;
+                       src = &data[i];
+               } while (i + 63 < len);
+
+               memset(temp, 0, sizeof(temp));
                j = 0;
        }
-       else i = 0;
-       memset(temp, 0, sizeof(temp));
-       memcpy(&sctx->buffer[j], &data[i], len - i);
+       memcpy(&sctx->buffer[j], src, len - i);
 }