dedup

commit 9a790f78b6623fd5340369f71e8649cefbe2d4ec
parent 22ec348a2fff0a5f80a3bdb4fc1bc0ffd4aec838
Author: sin <sin@2f30.org>
Date:   Sun, 17 Feb 2019 00:14:18 +0000

Tweaks

Diffstat:
M
dedup.c
 | 
9
+++++----

1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/dedup.c b/dedup.c
@@ -16,8 +16,9 @@
 #define STOREF	".store"
 #define CACHEF	".cache"
 
-#define BLKSIZ	65536
-#define WINSIZ	32
+#define BLKSIZ	(8*1024*1024)
+#define WINSIZ	4096
+#define HASHMSK	((1ul << 21) - 1)
 #define MDSIZ	SHA256_DIGEST_LENGTH
 
 #define ROTL(x, y) (((x) << (y)) | ((x) >> (32 - (y))))
@@ -134,14 +135,14 @@ chunk_blk(uint8_t *buf, size_t size)
 	/*
 	 * Chunking blocks is decided using a rolling hash + binary pattern.
 	 * The buzhash algorithm is used to "fingerprint" a fixed size window.
-	 * Once the lower 13 bits of this fingerprint are all zeros,
+	 * Once the lower bits of this fingerprint are all zeros,
 	 * the block is chunked.
 	 * If the pattern can't be matched, then we return the buffer size.
 	 */
 	fp = buzh_init(buf, WINSIZ);
 	for (i = 1; i < size - WINSIZ; i++) {
 		fp = buzh_update(fp, buf[i - 1], buf[i + WINSIZ - 1], WINSIZ);
-		if ((fp & 0x00001fff) == 0)
+		if ((fp & HASHMSK) == 0)
 			return i + WINSIZ;
 	}
 	return size;