Store params in chunker struct - dedup - deduplicating backup program
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---
DIR commit a41b0b187818a9659dda1fee972b8a9946889020
DIR parent 3d32364aa8deb41341b21c25b726239c6e9c295c
HTML 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(-)
---
DIR 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;
}