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new decodeSequence, merging parts

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This commit is contained in:
Yann Collet 2016-03-23 01:54:25 +01:00
parent add08d6f61
commit 9c34df93b6
1 changed files with 19 additions and 22 deletions
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41
lib/zstd_decompress.c
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@ -627,48 +627,45 @@ typedef struct {
static void ZSTD_decodeSequence(seq_t* seq, seqState_t* seqState, const U32 mls)
{
/* Literal length */
U32 const litCode = FSE_peekSymbol(&(seqState->stateLL));
{ static const U32 LL_base[MaxLL+1] = {
U32 const llCode = FSE_peekSymbol(&(seqState->stateLL));
U32 const mlCode = FSE_peekSymbol(&(seqState->stateML));
U32 const ofCode = FSE_peekSymbol(&(seqState->stateOffb)); /* <= maxOff, by table construction */
U32 const llBits = LL_bits[llCode];
U32 const mlBits = ML_bits[mlCode];
U32 const ofBits = ofCode ? ofCode-1 : 0;
static const U32 LL_base[MaxLL+1] = {
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
16, 18, 20, 22, 24, 28, 32, 40, 48, 64, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000,
0x2000, 0x4000, 0x8000, 0x10000 };
seq->litLength = LL_base[litCode] + BIT_readBits(&(seqState->DStream), LL_bits[litCode]);
}
/* MatchLength */
{ static const U32 ML_base[MaxML+1] = {
static const U32 ML_base[MaxML+1] = {
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
32, 34, 36, 38, 40, 44, 48, 56, 64, 80, 96, 0x80, 0x100, 0x200, 0x400, 0x800,
0x1000, 0x2000, 0x4000, 0x8000, 0x10000 };
U32 const mlCode = FSE_peekSymbol(&(seqState->stateML));
seq->matchLength = ML_base[mlCode] + BIT_readBits(&(seqState->DStream), ML_bits[mlCode]) + mls;
}
/* Offset */
{ static const U32 offsetPrefix[MaxOff+1] = {
static const U32 OF_base[MaxOff+1] = {
1 /*fake*/, 1, 2, 4, 8, 0x10, 0x20, 0x40,
0x80, 0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000,
0x8000, 0x10000, 0x20000, 0x40000, 0x80000, 0x100000, 0x200000, 0x400000,
0x800000, 0x1000000, 0x2000000, 0x4000000, /*fake*/ 1, 1, 1, 1 };
U32 const offsetCode = FSE_peekSymbol(&(seqState->stateOffb)); /* <= maxOff, by table construction */
U32 const nbBits = offsetCode ? offsetCode-1 : 0;
size_t const offset = offsetCode ? offsetPrefix[offsetCode] + BIT_readBits(&(seqState->DStream), nbBits) :
litCode ? seq->offset : seqState->prevOffset;
if (offsetCode | !litCode) seqState->prevOffset = seq->offset; /* cmove */
seq->litLength = LL_base[llCode] + BIT_readBits(&(seqState->DStream), llBits);
seq->matchLength = ML_base[mlCode] + BIT_readBits(&(seqState->DStream), mlBits) + mls;
/* Offset */
{ size_t const offset = ofCode ? OF_base[ofCode] + BIT_readBits(&(seqState->DStream), ofBits) :
llCode ? seq->offset : seqState->prevOffset;
if (ofCode | !llCode) seqState->prevOffset = seq->offset; /* cmove */
seq->offset = offset;
if (MEM_32bits()) BIT_reloadDStream(&(seqState->DStream));
}
/* ANS state update */
FSE_updateState(&(seqState->stateLL), &(seqState->DStream));
if (MEM_32bits()) BIT_reloadDStream(&(seqState->DStream));
FSE_updateState(&(seqState->stateML), &(seqState->DStream));
if (MEM_32bits()) BIT_reloadDStream(&(seqState->DStream));
FSE_updateState(&(seqState->stateOffb), &(seqState->DStream));
if (MEM_32bits()) BIT_reloadDStream(&(seqState->DStream));
}