diff options
| -rw-r--r-- | lz4.c | 21 |
1 files changed, 13 insertions, 8 deletions
@@ -160,6 +160,7 @@ int LZ4_compressCtx(void** ctx, BYTE* op = (BYTE*) dest;
+ const size_t DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };
int len, length;
const int skipStrength = SKIPSTRENGTH;
U32 forwardH;
@@ -227,13 +228,16 @@ _next_match: // Start Counting
ip+=MINMATCH; ref+=MINMATCH; // MinMatch verified
anchor = ip;
- while (A32(ref) == A32(ip))
+ while (ip<matchlimit-3)
{
- ip+=4; ref+=4;
- if (ip>matchlimit-4) { ref -= ip - (matchlimit-3); ip = matchlimit-3; break; }
+ int diff = A32(ref) ^ A32(ip);
+ if (!diff) { ip+=4; ref+=4; continue; }
+ ip += DeBruijnBytePos[((U32)((diff & -diff) * 0x077CB531U)) >> 27];
+ goto _endCount;
}
- if (A16(ref) == A16(ip)) { ip+=2; ref+=2; }
- if (*ref == *ip) ip++;
+ if ((ip<(matchlimit-1)) && (A16(ref) == A16(ip))) { ip+=2; ref+=2; }
+ if ((ip<matchlimit) && (*ref == *ip)) ip++;
+_endCount:
len = (ip - anchor);
// Encode MatchLength
@@ -298,6 +302,7 @@ int LZ4_compress64kCtx(void** ctx, BYTE* op = (BYTE*) dest;
+ const size_t DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };
int len, length;
const int skipStrength = SKIPSTRENGTH;
U32 forwardH;
@@ -366,9 +371,9 @@ _next_match: anchor = ip;
while (ip<matchlimit-3)
{
- if (A32(ref) == A32(ip)) { ip+=4; ref+=4; continue; }
- if (A16(ref) == A16(ip)) { ip+=2; ref+=2; }
- if (*ref == *ip) ip++;
+ int diff = A32(ref) ^ A32(ip);
+ if (!diff) { ip+=4; ref+=4; continue; }
+ ip += DeBruijnBytePos[((U32)((diff & -diff) * 0x077CB531U)) >> 27];
goto _endCount;
}
if ((ip<(matchlimit-1)) && (A16(ref) == A16(ip))) { ip+=2; ref+=2; }
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