HybridEidolon commented 4 years ago

Certain erroneous implementations of LZ77 have encodings that can't encode pointer shares of the standard maximum copy length of 258. In the linked example's case, for older iterations it can only copy up to 256 bytes in a single command. I figure that this may have been a performance optimization back in the 1990s, since newer games using this particular encoding have been fixed (though they still only support a window size of 8k).

This PR adds a Builder type to configure both the MAX_LENGTH constant and the already-configurable window size in the default compressor implementation, and changes existing constructor paths to use that builder. It is backwards-compatible with existing code. There may be a slight performance loss as a result under all paths, but nothing significant.

codecov-io commented 4 years ago

Codecov Report

Merging #48 into master will decrease coverage by 0.69%. The diff coverage is 50%.

@@            Coverage Diff            @@
##           master      #48     +/-   ##
=========================================
- Coverage   85.37%   84.67%   -0.7%     
=========================================
  Files          19       19             
  Lines        2119     2147     +28     
=========================================
+ Hits         1809     1818      +9     
- Misses        310      329     +19

Impacted Files	Coverage Δ
libflate_lz77/src/lib.rs	`100% <ø> (ø)`	:arrow_up:
libflate_lz77/src/default.rs	`74.57% <50%> (-13.21%)`	:arrow_down:

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sile commented 4 years ago

Published: https://crates.io/crates/libflate_lz77/0.1.1

sile / libflate

Make max share length in lz77 configurable #48

Codecov Report