zlib-ng / zlib-ng / 29500477949 / 4

93%

develop: 93%

push

github

Skip redundant hash slides for non-chain-walking strategies

deflate_quick reads only the head of each hash chain and never walks
prev, while Z_HUFFMAN_ONLY and Z_RLE read neither. Sliding the whole
hash on every window move is wasted work for them. Add a slide_hash_head
functable entry that slides only the head table, so deflate_quick slides
just the head and the huffman and rle strategies skip the slide entirely.

About 8% faster on the level-1 no-CRC deflate benchmark, output unchanged.

2167 of 2323 branches covered (93.28%)

Branch coverage included in aggregate %.

8426 of 9409 relevant lines covered (89.55%)

504795.14 hits per line