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author | Denys Vlasenko | 2018-12-12 16:44:34 +0100 |
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committer | Denys Vlasenko | 2018-12-12 16:44:34 +0100 |
commit | c2da68e896d4253466bed202e71bae7b9b2aeec9 (patch) | |
tree | 890bab87913e480fd0734dcc4e985b47a1f9021e | |
parent | 26819db9a3f029c1abaaf596fe1889315a203122 (diff) | |
download | busybox-c2da68e896d4253466bed202e71bae7b9b2aeec9.zip busybox-c2da68e896d4253466bed202e71bae7b9b2aeec9.tar.gz |
bc: optimize bc_parse_pushIndex()
function old new delta
bc_parse_pushIndex 80 68 -12
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r-- | miscutils/bc.c | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/miscutils/bc.c b/miscutils/bc.c index 73c801c..dc8e5c7 100644 --- a/miscutils/bc.c +++ b/miscutils/bc.c @@ -3460,16 +3460,23 @@ static void bc_parse_pushName(BcParse *p, char *name) static void bc_parse_pushIndex(BcParse *p, size_t idx) { - unsigned char amt, i, nums[sizeof(size_t)]; + size_t mask; + unsigned amt; -///oh boy - for (amt = 0; idx; ++amt) { - nums[amt] = (char) idx; - idx = (idx & ((unsigned long) ~(UCHAR_MAX))) >> sizeof(char) * CHAR_BIT; - } + mask = ((size_t)0xff) << (sizeof(idx) * 8 - 8); + amt = sizeof(idx); + do { + if (idx & mask) break; + mask >>= 8; + amt--; + } while (amt != 0); bc_parse_push(p, amt); - for (i = 0; i < amt; ++i) bc_parse_push(p, nums[i]); + + while (idx != 0) { + bc_parse_push(p, (unsigned char)idx); + idx >>= 8; + } } static void bc_parse_number(BcParse *p, BcInst *prev, size_t *nexs) |