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minor: better variable naming

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This commit is contained in:
Yann Collet 2024-10-10 16:07:20 -07:00
parent d45aee43f4
commit fa1fcb08ab
1 changed files with 14 additions and 14 deletions
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28
lib/compress/zstd_fast.c
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@ -97,10 +97,10 @@ void ZSTD_fillHashTable(ZSTD_matchState_t* ms,
} }
typedef int (*ZSTD_match4Found) (const BYTE* currentPtr, const BYTE* matchAddress, U32 currentIdx, U32 lowLimit); typedef int (*ZSTD_match4Found) (const BYTE* currentPtr, const BYTE* matchAddress, U32 matchIdx, U32 idxLowLimit);
static int static int
ZSTD_match4Found_cmov(const BYTE* currentPtr, const BYTE* matchAddress, U32 currentIdx, U32 lowLimit) ZSTD_match4Found_cmov(const BYTE* currentPtr, const BYTE* matchAddress, U32 matchIdx, U32 idxLowLimit)
{ {
/* Array of ~random data, should have low probability of matching data. /* Array of ~random data, should have low probability of matching data.
* Load from here if the index is invalid. * Load from here if the index is invalid.
@ -110,7 +110,7 @@ ZSTD_match4Found_cmov(const BYTE* currentPtr, const BYTE* matchAddress, U32 curr
/* currentIdx >= lowLimit is a (somewhat) unpredictable branch. /* currentIdx >= lowLimit is a (somewhat) unpredictable branch.
* However expression below compiles into conditional move. * However expression below compiles into conditional move.
*/ */
const BYTE* mvalAddr = ZSTD_selectAddr(currentIdx, lowLimit, matchAddress, dummy); const BYTE* mvalAddr = ZSTD_selectAddr(matchIdx, idxLowLimit, matchAddress, dummy);
/* Note: this used to be written as : return test1 && test2; /* Note: this used to be written as : return test1 && test2;
* Unfortunately, once inlined, these tests become branches, * Unfortunately, once inlined, these tests become branches,
* in which case it becomes critical that they are executed in the right order (test1 then test2). * in which case it becomes critical that they are executed in the right order (test1 then test2).
@ -121,17 +121,17 @@ ZSTD_match4Found_cmov(const BYTE* currentPtr, const BYTE* matchAddress, U32 curr
#if defined(__GNUC__) #if defined(__GNUC__)
__asm__(""); __asm__("");
#endif #endif
return currentIdx >= lowLimit; return matchIdx >= idxLowLimit;
} }
static int static int
ZSTD_match4Found_branch(const BYTE* currentPtr, const BYTE* matchAddress, U32 currentIdx, U32 lowLimit) ZSTD_match4Found_branch(const BYTE* currentPtr, const BYTE* matchAddress, U32 matchIdx, U32 idxLowLimit)
{ {
/* using a branch instead of a cmov, /* using a branch instead of a cmov,
* because it's faster in scenarios where currentIdx >= lowLimit is generally true, * because it's faster in scenarios where matchIdx >= idxLowLimit is generally true,
* aka almost all candidates are within range */ * aka almost all candidates are within range */
U32 mval; U32 mval;
if (currentIdx >= lowLimit) { if (matchIdx >= idxLowLimit) {
mval = MEM_read32(matchAddress); mval = MEM_read32(matchAddress);
} else { } else {
mval = MEM_read32(currentPtr) ^ 1; /* guaranteed to not match. */ mval = MEM_read32(currentPtr) ^ 1; /* guaranteed to not match. */
@ -219,7 +219,7 @@ size_t ZSTD_compressBlock_fast_noDict_generic(
size_t hash0; /* hash for ip0 */ size_t hash0; /* hash for ip0 */
size_t hash1; /* hash for ip1 */ size_t hash1; /* hash for ip1 */
U32 idx; /* match idx for ip0 */ U32 matchIdx; /* match idx for ip0 */
U32 offcode; U32 offcode;
const BYTE* match0; const BYTE* match0;
@ -261,7 +261,7 @@ _start: /* Requires: ip0 */
hash0 = ZSTD_hashPtr(ip0, hlog, mls); hash0 = ZSTD_hashPtr(ip0, hlog, mls);
hash1 = ZSTD_hashPtr(ip1, hlog, mls); hash1 = ZSTD_hashPtr(ip1, hlog, mls);
idx = hashTable[hash0]; matchIdx = hashTable[hash0];
do { do {
/* load repcode match for ip[2]*/ /* load repcode match for ip[2]*/
@ -289,7 +289,7 @@ _start: /* Requires: ip0 */
goto _match; goto _match;
} }
if (findMatch(ip0, base + idx, idx, prefixStartIndex)) { if (findMatch(ip0, base + matchIdx, matchIdx, prefixStartIndex)) {
/* found a match! */ /* found a match! */
/* Write next hash table entry (it's already calculated). /* Write next hash table entry (it's already calculated).
@ -301,7 +301,7 @@ _start: /* Requires: ip0 */
} }
/* lookup ip[1] */ /* lookup ip[1] */
idx = hashTable[hash1]; matchIdx = hashTable[hash1];
/* hash ip[2] */ /* hash ip[2] */
hash0 = hash1; hash0 = hash1;
@ -316,7 +316,7 @@ _start: /* Requires: ip0 */
current0 = (U32)(ip0 - base); current0 = (U32)(ip0 - base);
hashTable[hash0] = current0; hashTable[hash0] = current0;
if (findMatch(ip0, base + idx, idx, prefixStartIndex)) { if (findMatch(ip0, base + matchIdx, matchIdx, prefixStartIndex)) {
/* found a match! */ /* found a match! */
/* Write next hash table entry; it's already calculated */ /* Write next hash table entry; it's already calculated */
@ -331,7 +331,7 @@ _start: /* Requires: ip0 */
} }
/* lookup ip[1] */ /* lookup ip[1] */
idx = hashTable[hash1]; matchIdx = hashTable[hash1];
/* hash ip[2] */ /* hash ip[2] */
hash0 = hash1; hash0 = hash1;
@ -382,7 +382,7 @@ _cleanup:
_offset: /* Requires: ip0, idx */ _offset: /* Requires: ip0, idx */
/* Compute the offset code. */ /* Compute the offset code. */
match0 = base + idx; match0 = base + matchIdx;
rep_offset2 = rep_offset1; rep_offset2 = rep_offset1;
rep_offset1 = (U32)(ip0-match0); rep_offset1 = (U32)(ip0-match0);
offcode = OFFSET_TO_OFFBASE(rep_offset1); offcode = OFFSET_TO_OFFBASE(rep_offset1);