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deflate_compress: strengthen levels 10-12 slightly

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With deflate_compress_near_optimal(), some data benefits more than
originally thought from larger values of max_search_depth and
nice_match_length.  Some data even needs these parameters to be fairly
high for deflate_compress_near_optimal() to compress more than
deflate_compress_lazy2().  Bump these parameters up a bit.
This commit is contained in:
Eric Biggers 2021-12-31 16:04:49 -06:00
parent 69a7ca07fd
commit 8d4a5ae15c
1 changed files with 6 additions and 6 deletions
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12
lib/deflate_compress.c
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@ -3004,21 +3004,21 @@ libdeflate_alloc_compressor(int compression_level)
#if SUPPORT_NEAR_OPTIMAL_PARSING #if SUPPORT_NEAR_OPTIMAL_PARSING
case 10: case 10:
c->impl = deflate_compress_near_optimal; c->impl = deflate_compress_near_optimal;
c->max_search_depth = 30; c->max_search_depth = 35;
c->nice_match_length = 50; c->nice_match_length = 75;
c->p.n.num_optim_passes = 2; c->p.n.num_optim_passes = 2;
break; break;
case 11: case 11:
c->impl = deflate_compress_near_optimal; c->impl = deflate_compress_near_optimal;
c->max_search_depth = 60; c->max_search_depth = 70;
c->nice_match_length = 80; c->nice_match_length = 150;
c->p.n.num_optim_passes = 3; c->p.n.num_optim_passes = 3;
break; break;
case 12: case 12:
default: default:
c->impl = deflate_compress_near_optimal; c->impl = deflate_compress_near_optimal;
c->max_search_depth = 100; c->max_search_depth = 150;
c->nice_match_length = 133; c->nice_match_length = DEFLATE_MAX_MATCH_LEN;
c->p.n.num_optim_passes = 4; c->p.n.num_optim_passes = 4;
break; break;
#endif /* SUPPORT_NEAR_OPTIMAL_PARSING */ #endif /* SUPPORT_NEAR_OPTIMAL_PARSING */