aboutsummaryrefslogtreecommitdiff
path: root/archival
diff options
context:
space:
mode:
authorGravatar Natanael Copa <ncopa@alpinelinux.org>2016-08-03 16:21:52 +0200
committerGravatar Denys Vlasenko <vda.linux@googlemail.com>2016-08-15 01:26:28 +0200
commit71cfbce655bcfa6d3e0154d441a33d3bfd1dca57 (patch)
tree94ff19755254568b3f6dfc0fc6ed5131643b08fa /archival
parent7e6f9316a8bf3030da6c283e43aa0709d0cef259 (diff)
downloadbusybox-71cfbce655bcfa6d3e0154d441a33d3bfd1dca57.tar.gz
busybox-71cfbce655bcfa6d3e0154d441a33d3bfd1dca57.tar.bz2
gzip: fix compression level bug. Closes 9131
fix broken logic to get the gzip_level_config value from options -1 to -9. This fixes an off-by-one bug that caused gzip -9 output bigger files than the other compression levels. It fixes so that compression level 1 to 3 are actually mapped to level 4 as comments say. It also fixes that levels -4 to -9 is mapped to correct level and avoids out-of-bounds access. Signed-off-by: Natanael Copa <ncopa@alpinelinux.org> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'archival')
-rw-r--r--archival/gzip.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/archival/gzip.c b/archival/gzip.c
index 8f1e4ff29..9e0bee815 100644
--- a/archival/gzip.c
+++ b/archival/gzip.c
@@ -2220,10 +2220,7 @@ int gzip_main(int argc UNUSED_PARAM, char **argv)
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);
+ opt = ffs(opt >> 4); /* Maps -1..-4 to [0], -5 to [1] ... -9 to [5] */
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;