xref: /haiku/src/system/libroot/posix/musl/string/strcspn.c (revision 90dca2bc8ea3f248a1fe87fda98bc7f822dfcd38)
1*90dca2bcSAugustin Cavalier #define _DEFAULT_SOURCE
246a6070bSAugustin Cavalier #include <string.h>
346a6070bSAugustin Cavalier 
446a6070bSAugustin Cavalier #define BITOP(a,b,op) \
546a6070bSAugustin Cavalier  ((a)[(size_t)(b)/(8*sizeof *(a))] op (size_t)1<<((size_t)(b)%(8*sizeof *(a))))
646a6070bSAugustin Cavalier 
strcspn(const char * s,const char * c)746a6070bSAugustin Cavalier size_t strcspn(const char *s, const char *c)
846a6070bSAugustin Cavalier {
946a6070bSAugustin Cavalier 	const char *a = s;
1046a6070bSAugustin Cavalier 	size_t byteset[32/sizeof(size_t)];
1146a6070bSAugustin Cavalier 
1246a6070bSAugustin Cavalier 	if (!c[0] || !c[1]) return strchrnul(s, *c)-a;
1346a6070bSAugustin Cavalier 
1446a6070bSAugustin Cavalier 	memset(byteset, 0, sizeof byteset);
1546a6070bSAugustin Cavalier 	for (; *c && BITOP(byteset, *(unsigned char *)c, |=); c++);
1646a6070bSAugustin Cavalier 	for (; *s && !BITOP(byteset, *(unsigned char *)s, &); s++);
1746a6070bSAugustin Cavalier 	return s-a;
1846a6070bSAugustin Cavalier }
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