Le jeudi 14 juin 2007 à 10:14 +0200, Denis Vlasenko a écrit :
> From name I can infer that this function trims something from a string.
> What does it trim? where (from the start, end, both)?
if we can understand strchr() and strrchr(), we can naturally understand
bb_strtrim() and bb_strrtrim()
example:
char s[] = " BusyBox: The Swiss Army Knife of Embedded Linux ";
bb_strtrim(s, ':') = ": The Swiss Army Knife of Embedded Linux "
bb_strtrim(s, 0) = "BusyBox: The Swiss Army Knife of Embedded Linux "
we can rename it : bb_trim_leading()
bb_strrtrim(s, ':') = " BusyBox"
bb_strrtrim(s, 0) = " BusyBox: The Swiss Army Knife of Embedded Linux"
we can rename it : bb_trim_trailing()
bb_strtrim_index(s, 11) = ": The Swiss Army Knife of Embedded Linux "
bb_trim_leading_index()
bb_strrtrim_index(s, 11) = " BusyBox"
bb_trim_trailing_index()
bb_trimmed_slice(s, ':', 'K') = ": The Swiss Army"
bb_trim(s) = "BusyBox: The Swiss Army Knife of Embedded Linux"
> Try to have more descriptive names. This helps in understanding code,
> especially _at _callsites_.
>
> > {
> > char *t = NULL;
> >
> > if (!s) return NULL;
> >
> > if (c)
> > t = strchr(s, c);
> > else
> > t = s;
>
> First t = NULL is superfluous.
> >
> > t = skip_whitespace(t);
>
> If c!=0 and it is not found, we're toast (t==NULL).
Ok, I replaced strchr() by strchrnul()
> > memmove(s, t, strlen(t));
> > memset(s+strlen(t), 0, strlen(s)-strlen(t));
> > return s;
>
> Maybe just return strcpy(s,t) ?
In all cases the s is modified and memmove() authorizes the overlapping.
trim.c ================================================================
#include "libbb.h"
/*
* Beware: these functions modify the buffer
* The return value is there to simplify the tests:
* if (bb_strtrim(s, '#'))
* ...
*/
char *bb_strtrim(char *s, int c)
{
char *t;
if (!s) return NULL;
t = c ? strchrnul(s, c) : s;
if (t) {
t = skip_whitespace(t);
memmove(s, t, strlen(t));
memset(s+strlen(t), 0, strlen(s)-strlen(t));
}
return s;
}
char *bb_strrtrim(char *s, int c)
{
char *t;
if (!s) return NULL;
t = c ? strrchr(s, c) : s;
while (t-- > s) {
if (!isspace(*t)) {
t[1] = '\0';
break;
}
}
return s;
}
char *bb_strtrim_index(char *s, unsigned int i)
{
if (!s || i > strlen(s)) {
return (s = NULL);
}
return bb_strtrim(s, s[i]);
}
char *bb_strrtrim_index(char *s, unsigned int i)
{
if (!s || i > strlen(s)) {
return (s = NULL);
}
return bb_strrtrim(s, s[i]);
}
char *bb_trimmed_slice(char *s, int start_c, int end_c)
{
bb_strtrim(s, start_c);
bb_strrtrim(s, end_c);
return s;
}
char *bb_trim(char *s)
{
return bb_trimmed_slice(s, 0, 0);
}
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