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author | Yann Collet <cyan@fb.com> | 2018-05-02 17:33:12 (GMT) |
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committer | Yann Collet <cyan@fb.com> | 2018-05-02 17:33:12 (GMT) |
commit | 1a191b3f8d26b50a7c1d41590b529ec308d768cd (patch) | |
tree | 32953da64fa1ee687cafa564088153b4ed6b6e44 /lib/lz4.c | |
parent | 0114b63b40dd58267d8680605cd3000264ce2820 (diff) | |
download | lz4-1a191b3f8d26b50a7c1d41590b529ec308d768cd.zip lz4-1a191b3f8d26b50a7c1d41590b529ec308d768cd.tar.gz lz4-1a191b3f8d26b50a7c1d41590b529ec308d768cd.tar.bz2 |
simplify shortcut
Diffstat (limited to 'lib/lz4.c')
-rw-r--r-- | lib/lz4.c | 77 |
1 files changed, 22 insertions, 55 deletions
@@ -1429,62 +1429,29 @@ LZ4_FORCE_INLINE int LZ4_decompress_generic( */ if ((endOnInput ? length != RUN_MASK : length <= 8) && /* strictly "less than" on input, to re-enter the loop with at least one byte */ - likely((endOnInput ? ip < shortiend : 1) && (op <= shortoend))) + likely((endOnInput ? ip < shortiend : 1) & (op <= shortoend))) { - /* Can we copy the literals with a single memcpy invocation? Sometimes we can't - * copy 16 bytes, because they can clobber the dictionary in the ring buffer. */ - if (!endOnInput /* only 8 bytes */ || /* nothing to clobber */ dict != usingExtDict) { - /* Copy the literals. */ - memcpy(op, ip, endOnInput ? 16 : 8); - op += length; ip += length; - - /* The second stage: prepare for match copying, decode full info. - * It if doesn't work out, the info won't be wasted. */ - length = token & ML_MASK; /* match length */ - offset = LZ4_readLE16(ip); ip += 2; - match = op - offset; - - /* Do not deal with overlapping matches. */ - if ((length != 15) && (offset >= 8) && - (dict==withPrefix64k || match >= lowPrefix)) - { - /* Copy the match. */ - memcpy(op + 0, match + 0, 8); - memcpy(op + 8, match + 8, 8); - memcpy(op +16, match +16, 2); - op += length + MINMATCH; - /* Both stages worked, load the next token. */ - continue; - } - } else { - /* Save the literal length, can't copy 16 bytes just yet. */ - size_t ll = length; - - /* Prepare for the second satge. */ - length = token & ML_MASK; - offset = LZ4_readLE16(ip+ll); - match = op + ll - offset; - - if ((length != 15) && (offset >= 8) && - (dict==withPrefix64k || match >= lowPrefix)) - { - /* Copy the literals. */ - memcpy(op, ip, 16); - op += ll; ip += ll + 2; - /* Copy the match. */ - memcpy(op + 0, match + 0, 8); - memcpy(op + 8, match + 8, 8); - memcpy(op +16, match +16, 2); - op += length + MINMATCH; - /* Both stages worked, load the next token. */ - continue; - } - - /* So we took the literlas, but the second stage didn't work. */ - memcpy(op, ip, 8); - if (ll > 8) - memcpy(op + 8, ip + 8, 8); - op += ll; ip += ll + 2; + /* Copy the literals. */ + memcpy(op, ip, endOnInput ? 16 : 8); + op += length; ip += length; + + /* The second stage: prepare for match copying, decode full info. + * If it doesn't work out, the info won't be wasted. */ + length = token & ML_MASK; /* match length */ + offset = LZ4_readLE16(ip); ip += 2; + match = op - offset; + + /* Do not deal with overlapping matches. */ + if ((length != 15) && (offset >= 8) && + (dict==withPrefix64k || match >= lowPrefix)) + { + /* Copy the match. */ + memcpy(op + 0, match + 0, 8); + memcpy(op + 8, match + 8, 8); + memcpy(op +16, match +16, 2); + op += length + MINMATCH; + /* Both stages worked, load the next token. */ + continue; } /* The second stage didn't work out, but the info is ready. |