krak/zstd
1
0
Fork 0
mirror of https://github.com/facebook/zstd.git synced 2025-07-17 04:32:26 +02:00
Code Issues Releases 1 Activity

lib/compress: created ZSTD_LLcode() and ZSTD_MLcode()

Browse Source 
transform length into code.
Since transformation is needed in several places throughout the code,
better write the logic in one place.
This commit is contained in:
Yann Collet
2017-11-08 12:33:06 -08:00
parent 5aa0352742
commit 100d8ad6be
3 changed files with 40 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
lib/compress/zstd_opt.c
View File

@ -129,8 +129,7 @@ static U32 ZSTD_getLiteralPrice(optState_t* optPtr, U32 litLength, const BYTE* l
}
/* literal Length */
{ BYTE const LL_deltaCode = 19;
BYTE const llCode = (litLength>63) ? (BYTE)ZSTD_highbit32(litLength) + LL_deltaCode : LL_Code[litLength];
{ U32 const llCode = ZSTD_LLcode(litLength);
price += LL_bits[llCode] + optPtr->log2litLengthSum - ZSTD_highbit32(optPtr->litLengthFreq[llCode]+1);
}
@ -151,8 +150,7 @@ FORCE_INLINE_TEMPLATE U32 ZSTD_getPrice(optState_t* optPtr, U32 litLength, const
if (!ultra && offCode >= 20) price += (offCode-19)*2; /* handicap for long matches, to favor decompression speed */
/* match Length */
{ BYTE const ML_deltaCode = 36;
BYTE const mlCode = (mlBase>127) ? (BYTE)ZSTD_highbit32(mlBase) + ML_deltaCode : ML_Code[mlBase];
{ U32 const mlCode = ZSTD_MLcode(mlBase);
price += ML_bits[mlCode] + optPtr->log2matchLengthSum - ZSTD_highbit32(optPtr->matchLengthFreq[mlCode]+1);
}
@ -170,8 +168,7 @@ static void ZSTD_updatePrice(optState_t* optPtr, U32 litLength, const BYTE* lite
optPtr->litFreq[literals[u]] += ZSTD_LITFREQ_ADD;
/* literal Length */
{ const BYTE LL_deltaCode = 19;
const BYTE llCode = (litLength>63) ? (BYTE)ZSTD_highbit32(litLength) + LL_deltaCode : LL_Code[litLength];
{ const U32 llCode = ZSTD_LLcode(litLength);
optPtr->litLengthFreq[llCode]++;
optPtr->litLengthSum++;
}
@ -184,8 +181,7 @@ static void ZSTD_updatePrice(optState_t* optPtr, U32 litLength, const BYTE* lite
/* match Length */
{ U32 const mlBase = matchLength - MINMATCH;
const BYTE ML_deltaCode = 36;
const BYTE mlCode = (mlBase>127) ? (BYTE)ZSTD_highbit32(mlBase) + ML_deltaCode : ML_Code[mlBase];
U32 const mlCode = ZSTD_MLcode(mlBase);
optPtr->matchLengthFreq[mlCode]++;
optPtr->matchLengthSum++;
}