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created STORED_*() macros

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to act on values stored / expressed in the sumtype numeric representation required by `storedSeq()`.

This makes it possible to abstract away this representation by using the macros to extract these values.

First user : ZSTD_updateRep() .
This commit is contained in:
Yann Collet 2021-12-28 06:59:07 -08:00
parent 1aed962216
commit 2068889146
1 changed files with 39 additions and 33 deletions
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70
lib/compress/zstd_compress_internal.h
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@ -497,36 +497,6 @@ MEM_STATIC U32 ZSTD_MLcode(U32 mlBase)
return (mlBase > 127) ? ZSTD_highbit32(mlBase) + ML_deltaCode : ML_Code[mlBase];
}
typedef struct repcodes_s {
U32 rep[3];
} repcodes_t;
/* ZSTD_updateRep() :
* @offcode : expects a scale where 0,1,2 represent repcodes 1-3, and 2+ represents real_offset+2
*/
MEM_STATIC repcodes_t
ZSTD_updateRep(U32 const rep[3], U32 const offcode, U32 const ll0)
{
repcodes_t newReps;
if (offcode >= ZSTD_REP_NUM) { /* full offset */
newReps.rep[2] = rep[1];
newReps.rep[1] = rep[0];
newReps.rep[0] = offcode - ZSTD_REP_MOVE;
} else { /* repcode */
U32 const repCode = offcode + ll0;
if (repCode > 0) { /* note : if repCode==0, no change */
U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
newReps.rep[2] = (repCode >= 2) ? rep[1] : rep[2];
newReps.rep[1] = rep[0];
newReps.rep[0] = currentOffset;
} else { /* repCode == 0 */
ZSTD_memcpy(&newReps, rep, sizeof(newReps));
}
}
return newReps;
}
/* ZSTD_cParam_withinBounds:
* @return 1 if value is within cParam bounds,
* 0 otherwise */
@ -610,6 +580,10 @@ static void ZSTD_safecopyLiterals(BYTE* op, BYTE const* ip, BYTE const* const ie
#define STORE_REPCODE_3 STORE_REPCODE(3)
#define STORE_REPCODE(r) (assert((r)>=1), assert((r)<=3), (r)-1)
#define STORE_OFFSET(o) (assert((o)>0), o + ZSTD_REP_MOVE)
#define STORED_IS_OFFSET(o) ((o) > ZSTD_REP_MOVE)
#define STORED_IS_REPCODE(o) ((o) < ZSTD_REP_NUM)
#define STORED_OFFSET(o) (assert(STORED_IS_OFFSET(o)), (o)-ZSTD_REP_MOVE)
#define STORED_REPCODE(o) (assert(STORED_IS_REPCODE(o)), (o)+1) /* returns ID 1,2,3 */
/*! ZSTD_storeSeq() :
* Store a sequence (litlen, litPtr, offCode and matchLength) into seqStore_t.
@ -619,8 +593,11 @@ static void ZSTD_safecopyLiterals(BYTE* op, BYTE const* ip, BYTE const* const ie
* @matchLength : must be >= MINMATCH
* Allowed to overread literals up to litLimit.
*/
HINT_INLINE UNUSED_ATTR
void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const BYTE* literals, const BYTE* litLimit, U32 offBase_minus1, size_t matchLength)
HINT_INLINE UNUSED_ATTR void
ZSTD_storeSeq(seqStore_t* seqStorePtr,
size_t litLength, const BYTE* literals, const BYTE* litLimit,
U32 offBase_minus1,
size_t matchLength)
{
BYTE const* const litLimit_w = litLimit - WILDCOPY_OVERLENGTH;
BYTE const* const litEnd = literals + litLength;
@ -676,6 +653,35 @@ void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const BYTE* litera
seqStorePtr->sequences++;
}
typedef struct repcodes_s {
U32 rep[3];
} repcodes_t;
/* ZSTD_updateRep() :
* @offcode : sum-type, with same numeric representation as ZSTD_storeSeq()
*/
MEM_STATIC repcodes_t
ZSTD_updateRep(U32 const rep[3], U32 const offBase_minus1, U32 const ll0)
{
repcodes_t newReps;
if (STORED_IS_OFFSET(offBase_minus1)) { /* full offset */
newReps.rep[2] = rep[1];
newReps.rep[1] = rep[0];
newReps.rep[0] = STORED_OFFSET(offBase_minus1);
} else { /* repcode */
U32 const repCode = STORED_REPCODE(offBase_minus1) - 1 + ll0;
if (repCode > 0) { /* note : if repCode==0, no change */
U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
newReps.rep[2] = (repCode >= 2) ? rep[1] : rep[2];
newReps.rep[1] = rep[0];
newReps.rep[0] = currentOffset;
} else { /* repCode == 0 */
ZSTD_memcpy(&newReps, rep, sizeof(newReps));
}
}
return newReps;
}
/*-*************************************
* Match length counter