diff options
| -rw-r--r-- | archival/gzip.c | 72 |
1 files changed, 62 insertions, 10 deletions
diff --git a/archival/gzip.c b/archival/gzip.c index bc1f9c60b..42b2f0b2e 100644 --- a/archival/gzip.c +++ b/archival/gzip.c @@ -62,14 +62,27 @@ aa: 85.1% -- replaced with aa.gz //config: 1: larger buffers, larger hash-tables //config: 2: larger buffers, largest hash-tables //config: Larger models may give slightly better compression +//config: +//config:config FEATURE_GZIP_LEVELS +//config: bool "Enable compression levels" +//config: default n +//config: depends on GZIP +//config: help +//config: Enable support for compression levels 4-9. The default level +//config: is 6. If levels 1-3 are specified, 4 is used. +//config: If this option is not selected, -N options are ignored and -9 +//config: is used. //applet:IF_GZIP(APPLET(gzip, BB_DIR_BIN, BB_SUID_DROP)) //kbuild:lib-$(CONFIG_GZIP) += gzip.o //usage:#define gzip_trivial_usage -//usage: "[-cfd] [FILE]..." +//usage: "[-cfd" IF_FEATURE_GZIP_LEVELS("123456789") "] [FILE]..." //usage:#define gzip_full_usage "\n\n" //usage: "Compress FILEs (or stdin)\n" +//usage: IF_FEATURE_GZIP_LEVELS( +//usage: "\n -1..9 Compression level" +//usage: ) //usage: "\n -d Decompress" //usage: "\n -c Write to stdout" //usage: "\n -f Force" @@ -252,6 +265,8 @@ enum { * input file length plus MIN_LOOKAHEAD. */ +#ifndef ENABLE_FEATURE_GZIP_LEVELS + max_chain_length = 4096, /* To speed up deflation, hash chains are never searched beyond this length. * A higher limit improves compression ratio but degrades the speed. @@ -283,11 +298,23 @@ enum { * For deflate_fast() (levels <= 3) good is ignored and lazy has a different * meaning. */ +#endif /* ENABLE_FEATURE_GZIP_LEVELS */ }; struct globals { +#ifdef ENABLE_FEATURE_GZIP_LEVELS + unsigned max_chain_length; + unsigned max_lazy_match; + unsigned good_match; + unsigned nice_match; +#define max_chain_length (G1.max_chain_length) +#define max_lazy_match (G1.max_lazy_match) +#define good_match (G1.good_match) +#define nice_match (G1.nice_match) +#endif + lng block_start; /* window position at the beginning of the current output block. Gets @@ -2161,24 +2188,48 @@ int gzip_main(int argc UNUSED_PARAM, char **argv) #endif { unsigned opt; +#ifdef ENABLE_FEATURE_GZIP_LEVELS + static const struct { + uint8_t good; + uint8_t chain_shift; + uint8_t lazy2; + uint8_t nice2; + } gzip_level_config[6] = { + {4, 4, 4/2, 16/2}, /* Level 4 */ + {8, 5, 16/2, 32/2}, /* Level 5 */ + {8, 7, 16/2, 128/2}, /* Level 6 */ + {8, 8, 32/2, 128/2}, /* Level 7 */ + {32, 10, 128/2, 258/2}, /* Level 8 */ + {32, 12, 258/2, 258/2}, /* Level 9 */ + }; +#endif + + SET_PTR_TO_GLOBALS((char *)xzalloc(sizeof(struct globals)+sizeof(struct globals2)) + + sizeof(struct globals)); #if ENABLE_FEATURE_GZIP_LONG_OPTIONS applet_long_options = gzip_longopts; #endif /* Must match bbunzip's constants OPT_STDOUT, OPT_FORCE! */ - opt = getopt32(argv, "cfv" IF_GUNZIP("dt") "q123456789n"); + opt = getopt32(argv, "cfv" IF_GUNZIP("dt") "qn123456789"); #if ENABLE_GUNZIP /* gunzip_main may not be visible... */ if (opt & 0x18) // -d and/or -t return gunzip_main(argc, argv); #endif - option_mask32 &= 0x7; /* ignore -q, -0..9 */ - //if (opt & 0x1) // -c - //if (opt & 0x2) // -f - //if (opt & 0x4) // -v - argv += optind; - - SET_PTR_TO_GLOBALS((char *)xzalloc(sizeof(struct globals)+sizeof(struct globals2)) - + sizeof(struct globals)); +#ifdef ENABLE_FEATURE_GZIP_LEVELS + opt >>= ENABLE_GUNZIP ? 7 : 5; /* drop cfv[dt]qn bits */ + if (opt == 0) + opt = 1 << 6; /* default: 6 */ + /* Map 1..3 to 4 */ + if (opt & 0x7) + opt |= 1 << 4; + opt = ffs(opt >> 3); + max_chain_length = 1 << gzip_level_config[opt].chain_shift; + good_match = gzip_level_config[opt].good; + max_lazy_match = gzip_level_config[opt].lazy2 * 2; + nice_match = gzip_level_config[opt].nice2 * 2; +#endif + option_mask32 &= 0x7; /* retain only -cfv */ /* Allocate all global buffers (for DYN_ALLOC option) */ ALLOC(uch, G1.l_buf, INBUFSIZ); @@ -2190,5 +2241,6 @@ int gzip_main(int argc UNUSED_PARAM, char **argv) /* Initialize the CRC32 table */ global_crc32_table = crc32_filltable(NULL, 0); + argv += optind; return bbunpack(argv, pack_gzip, append_ext, "gz"); } |