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authorGravatar Aaro Koskinen <aaro.koskinen@iki.fi>2015-04-26 14:22:05 +0200
committerGravatar Denys Vlasenko <vda.linux@googlemail.com>2015-04-26 14:22:37 +0200
commitbbd53216f80912944da0d4ca72bf3ed3188ca156 (patch)
tree381920f0258b329ef591d7b4408441322b116c74 /archival
parent93b98ff5726fd620e1f123d04072b956412c1b55 (diff)
downloadbusybox-bbd53216f80912944da0d4ca72bf3ed3188ca156.tar.gz
busybox-bbd53216f80912944da0d4ca72bf3ed3188ca156.tar.bz2
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>
Diffstat (limited to 'archival')
-rw-r--r--archival/gzip.c72
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");
}