mirror of https://github.com/sheumann/hush.git
gzip: add support for compression levels 4-9
function old new delta gzip_main 192 282 +90 static.gzip_level_config - 24 +24 packed_usage 30439 30459 +20 fill_window 216 220 +4 pack_gzip 1789 1729 -60 ------------------------------------------------------------------------------ (add/remove: 1/0 grow/shrink: 3/1 up/down: 138/-60) Total: 78 bytes Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Aaro Koskinen
Denys Vlasenko
parent
93b98ff572
commit
bbd53216f8
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@ -62,14 +62,27 @@ aa: 85.1% -- replaced with aa.gz
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//config: 1: larger buffers, larger hash-tables
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//config: 2: larger buffers, largest hash-tables
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//config: Larger models may give slightly better compression
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//config:
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//config:config FEATURE_GZIP_LEVELS
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//config: bool "Enable compression levels"
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//config: default n
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//config: depends on GZIP
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//config: help
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//config: Enable support for compression levels 4-9. The default level
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//config: is 6. If levels 1-3 are specified, 4 is used.
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//config: If this option is not selected, -N options are ignored and -9
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//config: is used.
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//applet:IF_GZIP(APPLET(gzip, BB_DIR_BIN, BB_SUID_DROP))
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//kbuild:lib-$(CONFIG_GZIP) += gzip.o
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//usage:#define gzip_trivial_usage
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//usage: "[-cfd] [FILE]..."
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//usage: "[-cfd" IF_FEATURE_GZIP_LEVELS("123456789") "] [FILE]..."
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//usage:#define gzip_full_usage "\n\n"
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//usage: "Compress FILEs (or stdin)\n"
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//usage: IF_FEATURE_GZIP_LEVELS(
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//usage: "\n -1..9 Compression level"
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//usage: )
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//usage: "\n -d Decompress"
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//usage: "\n -c Write to stdout"
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//usage: "\n -f Force"
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@ -252,6 +265,8 @@ enum {
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* input file length plus MIN_LOOKAHEAD.
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*/
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#ifndef ENABLE_FEATURE_GZIP_LEVELS
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max_chain_length = 4096,
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/* To speed up deflation, hash chains are never searched beyond this length.
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* A higher limit improves compression ratio but degrades the speed.
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@ -283,11 +298,23 @@ enum {
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* For deflate_fast() (levels <= 3) good is ignored and lazy has a different
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* meaning.
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*/
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#endif /* ENABLE_FEATURE_GZIP_LEVELS */
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};
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struct globals {
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#ifdef ENABLE_FEATURE_GZIP_LEVELS
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unsigned max_chain_length;
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unsigned max_lazy_match;
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unsigned good_match;
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unsigned nice_match;
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#define max_chain_length (G1.max_chain_length)
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#define max_lazy_match (G1.max_lazy_match)
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#define good_match (G1.good_match)
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#define nice_match (G1.nice_match)
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#endif
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lng block_start;
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/* window position at the beginning of the current output block. Gets
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@ -2161,24 +2188,48 @@ int gzip_main(int argc UNUSED_PARAM, char **argv)
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#endif
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{
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unsigned opt;
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#ifdef ENABLE_FEATURE_GZIP_LEVELS
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static const struct {
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uint8_t good;
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uint8_t chain_shift;
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uint8_t lazy2;
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uint8_t nice2;
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} gzip_level_config[6] = {
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{4, 4, 4/2, 16/2}, /* Level 4 */
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{8, 5, 16/2, 32/2}, /* Level 5 */
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{8, 7, 16/2, 128/2}, /* Level 6 */
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{8, 8, 32/2, 128/2}, /* Level 7 */
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{32, 10, 128/2, 258/2}, /* Level 8 */
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{32, 12, 258/2, 258/2}, /* Level 9 */
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};
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#endif
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SET_PTR_TO_GLOBALS((char *)xzalloc(sizeof(struct globals)+sizeof(struct globals2))
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+ sizeof(struct globals));
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#if ENABLE_FEATURE_GZIP_LONG_OPTIONS
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applet_long_options = gzip_longopts;
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#endif
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/* Must match bbunzip's constants OPT_STDOUT, OPT_FORCE! */
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opt = getopt32(argv, "cfv" IF_GUNZIP("dt") "q123456789n");
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opt = getopt32(argv, "cfv" IF_GUNZIP("dt") "qn123456789");
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#if ENABLE_GUNZIP /* gunzip_main may not be visible... */
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if (opt & 0x18) // -d and/or -t
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return gunzip_main(argc, argv);
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#endif
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option_mask32 &= 0x7; /* ignore -q, -0..9 */
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//if (opt & 0x1) // -c
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//if (opt & 0x2) // -f
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//if (opt & 0x4) // -v
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argv += optind;
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SET_PTR_TO_GLOBALS((char *)xzalloc(sizeof(struct globals)+sizeof(struct globals2))
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+ sizeof(struct globals));
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#ifdef ENABLE_FEATURE_GZIP_LEVELS
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opt >>= ENABLE_GUNZIP ? 7 : 5; /* drop cfv[dt]qn bits */
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if (opt == 0)
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opt = 1 << 6; /* default: 6 */
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/* Map 1..3 to 4 */
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if (opt & 0x7)
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opt |= 1 << 4;
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opt = ffs(opt >> 3);
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max_chain_length = 1 << gzip_level_config[opt].chain_shift;
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good_match = gzip_level_config[opt].good;
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max_lazy_match = gzip_level_config[opt].lazy2 * 2;
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nice_match = gzip_level_config[opt].nice2 * 2;
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#endif
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option_mask32 &= 0x7; /* retain only -cfv */
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/* Allocate all global buffers (for DYN_ALLOC option) */
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ALLOC(uch, G1.l_buf, INBUFSIZ);
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@ -2190,5 +2241,6 @@ int gzip_main(int argc UNUSED_PARAM, char **argv)
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/* Initialize the CRC32 table */
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global_crc32_table = crc32_filltable(NULL, 0);
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argv += optind;
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return bbunpack(argv, pack_gzip, append_ext, "gz");
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}
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