On 7/2/20 12:02 AM, Jody Bruchon wrote:
> From 10389ff81b4ee5a7db293cf5d6205d8944e51901 Mon Sep 17 00:00:00 2001
> From: Jody Bruchon <[email protected]>
> Date: Wed, 1 Jul 2020 17:55:04 -0400
> Subject: [PATCH] libbb/last_char_is: rewrite for smaller and faster code
>
> Signed-off-by: Jody Bruchon <[email protected]>
> ---
> libbb/last_char_is.c | 14 +++++---------
> 1 file changed, 5 insertions(+), 9 deletions(-)
>
> diff --git a/libbb/last_char_is.c b/libbb/last_char_is.c
> index 918526e6c..b146b606f 100644
> --- a/libbb/last_char_is.c
> +++ b/libbb/last_char_is.c
> @@ -9,16 +9,12 @@
> #include "libbb.h"
>
> /* Find out if the last character of a string matches the one given */
> -char* FAST_FUNC last_char_is(const char *s, int c)
> +char* FAST_FUNC last_char_is(char *s, char c)
> {
> - if (s) {
> - size_t sz = strlen(s);
> - /* Don't underrun the buffer if the string length is 0 */
> - if (sz != 0) {
> - s += sz - 1;
> - if ((unsigned char)*s == c)
> - return (char*)s;
> - }
> + if (s && *s) {
> + while (*s != '\0') s++;
> + s--;
> + if (*s == c) return s;
> }
> return NULL;
> }
hi,
just for fun I add my version:
char* FAST_FUNC last_char_is(const char *s, int c) {
while (s && *s && *(s + 1)) s++;
return (c == *s) ? (char *)s : NULL;
}
make bloatcheck
function old new delta
last_char_is 53 47 -6
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-6) Total: -6 bytes
text data bss dec hex filename
980860 16891 1872 999623 f40c7 busybox_old
980854 16891 1872 999617 f40c1 busybox_unstripped
Ciao,
Tito
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