[FFmpeg-devel] [PATCH] md5: avoid unnecessary memcpy.

[Reimar Döffinger]

---
 libavutil/md5.c |   31 ++++++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/libavutil/md5.c b/libavutil/md5.c
index f8f08f1..3a87e2a 100644
--- a/libavutil/md5.c
+++ b/libavutil/md5.c
@@ -139,20 +139,37 @@ void av_md5_init(AVMD5 *ctx)
     ctx->ABCD[3] = 0x67452301;
 }
 
-void av_md5_update(AVMD5 *ctx, const uint8_t *src, const int len)
+void av_md5_update(AVMD5 *ctx, const uint8_t *src, int len)
 {
+    const uint8_t *end;
     int i, j;
 
     j = ctx->len & 63;
     ctx->len += len;
 
-    for (i = 0; i < len; i++) {
-        ctx->block[j++] = src[i];
-        if (j == 64) {
-            body(ctx->ABCD, (uint32_t *) ctx->block);
-            j = 0;
-        }
+    if (j) {
+        int cnt = FFMIN(len, 64 - j);
+        memcpy(ctx->block + j, src, cnt);
+        src += cnt;
+        len -= cnt;
+        if (j + cnt < 64)
+            return;
+        body(ctx->ABCD, (uint32_t *)ctx->block);
     }
+
+    end = src + (len & ~63);
+    while (src < end) {
+#if HAVE_FAST_UNALIGNED
+       body(ctx->ABCD, (uint32_t *)src);
+#else
+       memcpy(ctx->block, src, 64);
+       body(ctx->ABCD, (uint32_t *) ctx->block);
+#endif
+       src += 64;
+    }
+    len &= 63;
+    if (len > 0)
+        memcpy(ctx->block, src, len);
 }
 
 void av_md5_final(AVMD5 *ctx, uint8_t *dst)
-- 
1.7.10.4