From: Yann Collet <yann.collet.73@gmail.com>
Date: Fri, 25 Mar 2016 10:43:48 +0000 (+0100)
Subject: improved decompression speed (680)
X-Git-Tag: v0.6.0^2~17^2~28^2~14
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=433a5cce7ec75f421da8bbb677d07e36dd55e467;p=thirdparty%2Fzstd.git

improved decompression speed (680)
---

diff --git a/lib/zstd_compress.c b/lib/zstd_compress.c
index f79109a1d..1c4d83c98 100644
--- a/lib/zstd_compress.c
+++ b/lib/zstd_compress.c
@@ -798,9 +798,9 @@ MEM_STATIC void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const B
     static const BYTE* g_start = NULL;
     const U32 pos = (U32)(literals - g_start);
     if (g_start==NULL) g_start = literals;
-    if ((pos > 23945000) && (pos < 23946800))
-    printf("Cpos %6u :%4u literals & match %3u bytes at distance %6u \n",
-           pos, (U32)litLength, (U32)matchCode+MINMATCH, (U32)offsetCode);
+    if ((pos > 15181500) && (pos < 15183150))
+        printf("Cpos %6u :%4u literals & match %3u bytes at distance %6u \n",
+               pos, (U32)litLength, (U32)matchCode+MINMATCH, (U32)offsetCode);
 #endif
 #if ZSTD_OPT_DEBUG == 3
     if (offsetCode == 0) seqStorePtr->realRepSum++;
diff --git a/lib/zstd_decompress.c b/lib/zstd_decompress.c
index 48614c358..f0b695a53 100644
--- a/lib/zstd_decompress.c
+++ b/lib/zstd_decompress.c
@@ -637,9 +637,7 @@ static void ZSTD_decodeSequence(seq_t* seq, seqState_t* seqState, const U32 mls)
     U32 const ofBits = ofCode;
     U32 const totalBits = llBits+mlBits+ofBits;
 
-    size_t const allBits = BIT_readBits(&(seqState->DStream), totalBits);
-
-    if (totalBits > 64 - 7 - (LLFSELog+MLFSELog+OffFSELog)) BIT_reloadDStream(&(seqState->DStream));
+    //size_t const allBits = BIT_readBits(&(seqState->DStream), totalBits);
 
     static const U32 LL_base[MaxLL+1] = {
                              0,  1,  2,  3,  4,  5,  6,  7,  8,  9,   10,    11,    12,    13,    14,     15,
@@ -659,13 +657,15 @@ static void ZSTD_decodeSequence(seq_t* seq, seqState_t* seqState, const U32 mls)
                  0xFFFFFF, 0x1FFFFFF, 0x3FFFFFF, /*fake*/ 1, 1, 1, 1, 1 };
 
     /* sequence */
-    seq->litLength = LL_base[llCode] + BIT_getLowerBits(allBits, llBits);
-    seq->matchLength = ML_base[mlCode] + mls + BIT_getMiddleBits(allBits, mlBits, llBits);
-    {   size_t const offset = ofCode ? OF_base[ofCode] + BIT_getUpperBits(allBits, llBits+mlBits) :
+    {   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;
     }
+    seq->matchLength = ML_base[mlCode] + mls + ((mlCode>31) ? BIT_readBits(&(seqState->DStream), mlBits) : 0);
+    seq->litLength = LL_base[llCode] + ((llCode>15) ? BIT_readBits(&(seqState->DStream), llBits) : 0);
+
+    if (totalBits > 64 - 7 - (LLFSELog+MLFSELog+OffFSELog)) BIT_reloadDStream(&(seqState->DStream));
 
     /* ANS state update */
     FSE_updateState(&(seqState->stateLL), &(seqState->DStream));
@@ -795,7 +795,7 @@ static size_t ZSTD_decompressSequences(
             ZSTD_decodeSequence(&sequence, &seqState, mls);
 #if 0  /* for debug */
             {   U32 pos = (U32)(op-base);
-                if ((pos > 23945280) && (pos < 23946797))
+                if ((pos > 15181500) && (pos < 15183150))
                     printf("Dpos %6u : %3u literals & match %3u bytes at distance %6u \n",
                         pos, (U32)sequence.litLength, (U32)sequence.matchLength, (U32)sequence.offset);
             }