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Adjust Rabin parameters for chunksize > LZMA window size.

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This commit is contained in:
Moinak Ghosh 2012-07-07 00:01:13 +05:30
parent ea923b84f0
commit 172432698e
2 changed files with 4 additions and 3 deletions
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6
rabin/rabin_polynomial.c
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@ -96,12 +96,12 @@ create_rabin_context(uint64_t chunksize, uint64_t real_chunksize, const char *al
int level = 14;
/*
* For LZMA we use 4K minimum Rabin block size. For everything else it
* is 1K based on experimentation.
* For LZMA with chunksize <= LZMA Window size we use 4K minimum Rabin
* block size. For everything else it is 1K based on experimentation.
*/
ctx = (rabin_context_t *)slab_alloc(NULL, sizeof (rabin_context_t));
ctx->rabin_poly_max_block_size = RAB_POLYNOMIAL_MAX_BLOCK_SIZE;
if (memcmp(algo, "lzma", 4) == 0) {
if (memcmp(algo, "lzma", 4) == 0 && chunksize <= LZMA_WINDOW_MAX) {
ctx->rabin_poly_min_block_size = RAB_POLYNOMIAL_MIN_BLOCK_SIZE;
ctx->rabin_avg_block_mask = RAB_POLYNOMIAL_AVG_BLOCK_MASK;
ctx->rabin_poly_avg_block_size = RAB_POLYNOMIAL_AVG_BLOCK_SIZE;

1
rabin/rabin_polynomial.h
View file

@ -79,6 +79,7 @@
#define RAB_POLYNOMIAL_AVG_BLOCK_MASK2 (RAB_POLYNOMIAL_AVG_BLOCK_SIZE - 1)
#define RAB_POLYNOMIAL_MIN_BLOCK_SIZE2 2048
#define LZMA_WINDOW_MAX (128L * 1024L * 1024L)
#define RAB_POLYNOMIAL_WIN_SIZE 31
#define RAB_POLYNOMIAL_MIN_WIN_SIZE 17
#define RAB_POLYNOMIAL_MAX_WIN_SIZE 63