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gzip: code shrink

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function                                             old     new   delta
gzip_main                                            267     264      -3

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2019-09-05 13:22:24 +02:00
parent c660cc1b77
commit 750137ef7c
1 changed files with 9 additions and 9 deletions
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10
archival/gzip.c
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@ -259,7 +259,7 @@ enum {
#if !ENABLE_FEATURE_GZIP_LEVELS
comp_level = 6,
comp_level_minus4 = 6 - 4,
max_chain_length = 128,
/* To speed up deflation, hash chains are never searched beyond this length.
* A higher limit improves compression ratio but degrades the speed.
@ -335,12 +335,12 @@ struct globals {
#define head (G1.prev + WSIZE) /* hash head (see deflate.c) */
#if ENABLE_FEATURE_GZIP_LEVELS
unsigned comp_level;
unsigned comp_level_minus4; /* can be a byte */
unsigned max_chain_length;
unsigned max_lazy_match;
unsigned good_match;
unsigned nice_match;
#define comp_level (G1.comp_level)
#define comp_level_minus4 (G1.comp_level_minus4)
#define max_chain_length (G1.max_chain_length)
#define max_lazy_match (G1.max_lazy_match)
#define good_match (G1.good_match)
@ -2082,7 +2082,7 @@ static void zip(void)
deflate_flags = 0x300; /* extra flags. OS id = 3 (Unix) */
#if ENABLE_FEATURE_GZIP_LEVELS
/* Note that comp_level < 4 do not exist in this version of gzip */
if (comp_level == 9) {
if (comp_level_minus4 == 9 - 4) {
deflate_flags |= 0x02; /* SLOW flag */
}
#endif
@ -2232,7 +2232,7 @@ int gzip_main(int argc UNUSED_PARAM, char **argv)
opt = 1 << 5; /* default: 6 */
opt = ffs(opt >> 4); /* Maps -1..-4 to [0], -5 to [1] ... -9 to [5] */
comp_level = opt + 4;
comp_level_minus4 = opt;
max_chain_length = 1 << gzip_level_config[opt].chain_shift;
good_match = gzip_level_config[opt].good;