AuroraMiddleware/lz4
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small modification of lz4 decoder to shortcut common case (short branch).

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This commit is contained in:
Yann Collet 2017-10-25 10:10:53 +02:00
parent dccf8826f1
commit a31b7058cb
1 changed files with 16 additions and 0 deletions
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16
lib/lz4.c
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@ -1180,6 +1180,22 @@ LZ4_FORCE_INLINE int LZ4_decompress_generic(
/* get literal length */
unsigned const token = *ip++;
if (1)
if (ip + 14 + 2 <= iend)
if ((token < 15*16) & ((token & 0xF) <= 12)) {
size_t const ll = token >> ML_BITS;
size_t const off = LZ4_readLE16(ip+ll); /* check input validity */
if (off >= 16) {
size_t const ml = (token & 0xF) + MINMATCH;
DEBUGLOG(2, "rest:%u, ll:%2u, ml:%2u, off:%u",
(U32)(oend-op), (U32)ll, (U32)ml, (U32)off);
memcpy(op, ip, 16); op += ll; ip += ll + 2 /* offset */;
memcpy(op, op - off, 16); op += ml;
continue;
}
}
if ((length=(token>>ML_BITS)) == RUN_MASK) {
unsigned s;
do {