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updated compression level table for btlazy2

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now selected for levels 13, 14 and 15.

Also : dropped the requirement for monotonic memory budget increase of compression levels,,
which was required for ZSTD_estimateCCtxSize()
in order to ensure that a memory budget for level L is large enough for any level <= L.
This condition is now ensured at run time inside ZSTD_estimateCCtxSize().
This commit is contained in:
Yann Collet
2017-12-30 11:37:18 +01:00
parent eb52e2f45e
commit a68b76afef
1 changed files with 27 additions and 33 deletions
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60
lib/compress/zstd_compress.c
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@@ -687,12 +687,23 @@ size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams)
return ZSTD_estimateCCtxSize_usingCCtxParams(&params);
}
size_t ZSTD_estimateCCtxSize(int compressionLevel)
static size_t ZSTD_estimateCCtxSize_internal(int compressionLevel)
{
ZSTD_compressionParameters const cParams = ZSTD_getCParams(compressionLevel, 0, 0);
return ZSTD_estimateCCtxSize_usingCParams(cParams);
}
size_t ZSTD_estimateCCtxSize(int compressionLevel)
{
int level;
size_t memBudget = 0;
for (level=1; level<=compressionLevel; level++) {
size_t const newMB = ZSTD_estimateCCtxSize_internal(level);
if (newMB > memBudget) memBudget = newMB;
}
return memBudget;
}
size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params)
{
if (params->nbThreads > 1) { return ERROR(GENERIC); }
@@ -712,11 +723,21 @@ size_t ZSTD_estimateCStreamSize_usingCParams(ZSTD_compressionParameters cParams)
return ZSTD_estimateCStreamSize_usingCCtxParams(&params);
}
size_t ZSTD_estimateCStreamSize(int compressionLevel) {
static size_t ZSTD_estimateCStreamSize_internal(int compressionLevel) {
ZSTD_compressionParameters const cParams = ZSTD_getCParams(compressionLevel, 0, 0);
return ZSTD_estimateCStreamSize_usingCParams(cParams);
}
size_t ZSTD_estimateCStreamSize(int compressionLevel) {
int level;
size_t memBudget = 0;
for (level=1; level<=compressionLevel; level++) {
size_t const newMB = ZSTD_estimateCStreamSize_internal(level);
if (newMB > memBudget) memBudget = newMB;
}
return memBudget;
}
static U32 ZSTD_equivalentCParams(ZSTD_compressionParameters cParams1,
ZSTD_compressionParameters cParams2)
{
@@ -3001,9 +3022,9 @@ static const ZSTD_compressionParameters ZSTD_defaultCParameters[4][ZSTD_MAX_CLEV
{ 21, 19, 21, 4, 5, 16, ZSTD_lazy2 }, /* level 10 */
{ 22, 20, 22, 4, 5, 16, ZSTD_lazy2 }, /* level 11 */
{ 22, 20, 22, 5, 5, 16, ZSTD_lazy2 }, /* level 12 */
{ 22, 21, 22, 5, 5, 16, ZSTD_lazy2 }, /* level 13 */
{ 22, 21, 22, 6, 5, 16, ZSTD_lazy2 }, /* level 14 */
{ 22, 21, 22, 5, 5, 16, ZSTD_btlazy2 }, /* level 15 */
{ 22, 21, 22, 4, 5, 16, ZSTD_btlazy2 }, /* level 13 */
{ 22, 21, 22, 5, 5, 16, ZSTD_btlazy2 }, /* level 14 */
{ 22, 22, 22, 6, 5, 16, ZSTD_btlazy2 }, /* level 15 */
{ 22, 21, 22, 4, 5, 48, ZSTD_btopt }, /* level 16 */
{ 23, 22, 22, 4, 4, 48, ZSTD_btopt }, /* level 17 */
{ 23, 22, 22, 5, 3, 64, ZSTD_btopt }, /* level 18 */
@@ -3092,41 +3113,14 @@ static const ZSTD_compressionParameters ZSTD_defaultCParameters[4][ZSTD_MAX_CLEV
},
};
#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG>=1)
/* This function just controls
* the monotonic memory budget increase of ZSTD_defaultCParameters[0].
* Run once, on first ZSTD_getCParams() usage, if ZSTD_DEBUG is enabled
*/
MEM_STATIC void ZSTD_check_compressionLevel_monotonicIncrease_memoryBudget(void)
{
int level;
for (level=1; level<ZSTD_maxCLevel(); level++) {
ZSTD_compressionParameters const c1 = ZSTD_defaultCParameters[0][level];
ZSTD_compressionParameters const c2 = ZSTD_defaultCParameters[0][level+1];
assert(c1.windowLog <= c2.windowLog);
# define ZSTD_TABLECOST(h,c) ((1<<(h)) + (1<<(c)))
assert(ZSTD_TABLECOST(c1.hashLog, c1.chainLog) <= ZSTD_TABLECOST(c2.hashLog, c2.chainLog));
}
}
#endif
/*! ZSTD_getCParams() :
* @return ZSTD_compressionParameters structure for a selected compression level, `srcSize` and `dictSize`.
* @return ZSTD_compressionParameters structure for a selected compression level, srcSize and dictSize.
* Size values are optional, provide 0 if not known or unused */
ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long srcSizeHint, size_t dictSize)
{
size_t const addedSize = srcSizeHint ? 0 : 500;
U64 const rSize = srcSizeHint+dictSize ? srcSizeHint+dictSize+addedSize : (U64)-1;
U32 const tableID = (rSize <= 256 KB) + (rSize <= 128 KB) + (rSize <= 16 KB); /* intentional underflow for srcSizeHint == 0 */
#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG>=1)
static int g_monotonicTest = 1;
if (g_monotonicTest) {
ZSTD_check_compressionLevel_monotonicIncrease_memoryBudget();
g_monotonicTest=0;
}
#endif
DEBUGLOG(4, "ZSTD_getCParams: cLevel=%i, srcSize=%u, dictSize=%u => table %u",
compressionLevel, (U32)srcSizeHint, (U32)dictSize, tableID);
if (compressionLevel <= 0) compressionLevel = ZSTD_CLEVEL_DEFAULT; /* 0 == default; no negative compressionLevel yet */