dedup

commit a41b0b187818a9659dda1fee972b8a9946889020
parent 3d32364aa8deb41341b21c25b726239c6e9c295c
Author: sin <sin@2f30.org>
Date:   Fri,  8 Mar 2019 11:35:36 +0000

Store params in chunker struct

Diffstat:
M
chunker.c
 | 
54
+++++++++++++++++++++++++++++++++---------------------

1 file changed, 33 insertions(+), 21 deletions(-)
diff --git a/chunker.c b/chunker.c
@@ -15,6 +15,10 @@ struct chunker {
 	size_t cap;
 	size_t rpos;
 	size_t wpos;
+	size_t min_size;
+	size_t max_size;
+	size_t mask;
+	size_t win_size;
 };
 
 /*
@@ -65,40 +69,41 @@ static uint32_t buz[] = {
 static inline uint32_t
 buzh_init(uint8_t *buf, size_t size)
 {
-	uint32_t fp;
+	uint32_t sum;
 	size_t i;
 
-	for (i = 1, fp = 0; i < size; i++, buf++)
-		fp ^= ROTL(buz[*buf], (size - i) % 32);
+	for (i = 1, sum = 0; i < size; i++, buf++)
+		sum ^= ROTL(buz[*buf], (size - i) % 32);
 
-	return fp ^ buz[*buf];
+	return sum ^ buz[*buf];
 }
 
 static inline uint32_t
-buzh_update(uint32_t fp, uint8_t out, uint8_t in, size_t size)
+buzh_update(uint32_t sum, uint8_t out, uint8_t in, size_t size)
 {
-	return ROTL(fp, 1) ^ ROTL(buz[out], size % 32) ^ buz[in];
+	return ROTL(sum, 1) ^ ROTL(buz[out], size % 32) ^ buz[in];
 }
 
 static inline int
-match_pattern(size_t chunk_size, uint32_t fp)
+match_pattern(struct chunker *chunker, size_t chunk_size, uint32_t sum)
 {
-	if (chunk_size >= BLKSIZE_MAX)
+	if (chunk_size >= chunker->max_size)
 		return 1;
-	if (chunk_size < BLKSIZE_MIN)
+	if (chunk_size < chunker->min_size)
 		return 0;
-	return (fp & HASHMASK_BITS) == 0;
+	return (sum & chunker->mask) == 0;
 }
 
 static size_t
 get_chunk_size(struct chunker *chunker)
 {
+	size_t chunk_size, win_size, i;
+	uint32_t sum;
 	uint8_t *bp;
-	uint32_t fp;
-	size_t i, chunk_size;
 
 	chunk_size = chunker->wpos - chunker->rpos;
-	if (chunk_size < WINSIZE)
+	win_size = chunker->win_size;
+	if (chunk_size < win_size)
 		return chunk_size;
 
 	/*
@@ -110,14 +115,17 @@ get_chunk_size(struct chunker *chunker)
 	 * at the end of that window.
 	 */
 	bp = &chunker->buf[chunker->rpos];
-	fp = buzh_init(bp, WINSIZE);
-	for (i = 0; i < chunk_size - WINSIZE; i++) {
-		if (i > 0)
-			fp = buzh_update(fp, bp[i - 1], bp[i + WINSIZE - 1],
-			                 WINSIZE);
-		if (match_pattern(i + WINSIZE, fp))
-			return i + WINSIZE;
-			
+	sum = buzh_init(bp, win_size);
+	for (i = 0; i < chunk_size - win_size; i++) {
+		if (i > 0) {
+			uint8_t out = bp[i - 1];
+			uint8_t in = bp[i + win_size - 1];
+
+			sum = buzh_update(sum, out, in, win_size);
+		}
+
+		if (match_pattern(chunker, i + win_size, sum))
+			return i + win_size;
 	}
 	return chunk_size;
 }
@@ -136,6 +144,10 @@ alloc_chunker(int fd, size_t cap)
 		err(1, "calloc");
 	chunker->fd = fd;
 	chunker->cap = cap;
+	chunker->min_size = BLKSIZE_MIN;
+	chunker->max_size = BLKSIZE_MAX;
+	chunker->mask = HASHMASK_BITS;
+	chunker->win_size = WINSIZE;
 
 	return chunker;
 }