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experiments with ZSTD_decodeSequence

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This commit is contained in:
inikep
2016-04-05 10:08:25 +02:00
parent 2ec2698ef9
commit b3532793a9
2 changed files with 55 additions and 30 deletions
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lib/zstd_decompress.c
+44 -30
View File
@@ -687,45 +687,59 @@ static void ZSTD_decodeSequence(seq_t* seq, seqState_t* seqState, const U32 mls)
{ size_t offset;
if (ofCode) {
offset = OF_base[ofCode] + BIT_readBits(&(seqState->DStream), ofBits); /* <= 26 bits */
if (MEM_32bits()) BIT_reloadDStream(&(seqState->DStream));
} else {
offset = 0;
}
if (offset < ZSTD_REP_NUM) {
if (llCode == 0 && offset <= 1) offset = 1-offset;
if (offset != 0) {
size_t temp = seqState->prevOffset[offset];
if (offset != 1) {
if (offset == 3) seqState->prevOffset[3] = seqState->prevOffset[2];
seqState->prevOffset[2] = seqState->prevOffset[1];
}
#if 0
if (!ofCode) {
if (!llCode) {
offset = seqState->prevOffset[1];
seqState->prevOffset[1] = seqState->prevOffset[0];
seqState->prevOffset[0] = offset = temp;
seqState->prevOffset[0] = offset;
} else {
offset = seqState->prevOffset[0];
}
} else {
offset -= ZSTD_REP_MOVE;
#if 1 // faster without kSlotNew
seqState->prevOffset[3] = seqState->prevOffset[2];
seqState->prevOffset[2] = seqState->prevOffset[1];
seqState->prevOffset[1] = seqState->prevOffset[0];
seqState->prevOffset[0] = offset;
offset = OF_base[ofCode] + BIT_readBits(&(seqState->DStream), ofBits); /* <= 26 bits */
if (MEM_32bits()) BIT_reloadDStream(&(seqState->DStream));
#else
if (kSlotNew < 3) seqState->prevOffset[3] = seqState->prevOffset[2];
if (kSlotNew < 2) seqState->prevOffset[2] = seqState->prevOffset[1];
if (kSlotNew < 1) seqState->prevOffset[1] = seqState->prevOffset[0];
seqState->prevOffset[kSlotNew] = offset;
#endif
if (!ofCode)
offset = 0;
else {
offset = OF_base[ofCode] + BIT_readBits(&(seqState->DStream), ofBits); /* <= 26 bits */
if (MEM_32bits()) BIT_reloadDStream(&(seqState->DStream));
}
{
#endif
if (offset < ZSTD_REP_NUM) {
if (llCode == 0 && offset <= 1) offset = 1-offset;
if (offset != 0) {
size_t temp = seqState->prevOffset[offset];
if (offset != 1) {
if (offset == 3) seqState->prevOffset[3] = seqState->prevOffset[2];
seqState->prevOffset[2] = seqState->prevOffset[1];
}
seqState->prevOffset[1] = seqState->prevOffset[0];
seqState->prevOffset[0] = offset = temp;
} else {
offset = seqState->prevOffset[0];
}
} else {
offset -= ZSTD_REP_MOVE;
#if 1 // faster without kSlotNew
seqState->prevOffset[3] = seqState->prevOffset[2];
seqState->prevOffset[2] = seqState->prevOffset[1];
seqState->prevOffset[1] = seqState->prevOffset[0];
seqState->prevOffset[0] = offset;
#else
if (kSlotNew < 3) seqState->prevOffset[3] = seqState->prevOffset[2];
if (kSlotNew < 2) seqState->prevOffset[2] = seqState->prevOffset[1];
if (kSlotNew < 1) seqState->prevOffset[1] = seqState->prevOffset[0];
seqState->prevOffset[kSlotNew] = offset;
#endif
}
}
seq->offset = offset;
}
lib/zstd_internal.h
+11
View File
@@ -46,6 +46,17 @@
#define MIN(a,b) ((a)<(b) ? (a) : (b))
#define MAX(a,b) ((a)>(b) ? (a) : (b))
#define ZSTD_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
#if (ZSTD_GCC_VERSION >= 302) || (__INTEL_COMPILER >= 800) || defined(__clang__)
# define expect(expr,value) (__builtin_expect ((expr),(value)) )
#else
# define expect(expr,value) (expr)
#endif
#define likely(expr) expect((expr) != 0, 1)
#define unlikely(expr) expect((expr) != 0, 0)
/*-*************************************
* Common constants