xref: /aosp_15_r20/external/musl/src/string/strchrnul.c (revision c9945492fdd68bbe62686c5b452b4dc1be3f8453)
1*c9945492SAndroid Build Coastguard Worker #include <string.h>
2*c9945492SAndroid Build Coastguard Worker #include <stdint.h>
3*c9945492SAndroid Build Coastguard Worker #include <limits.h>
4*c9945492SAndroid Build Coastguard Worker 
5*c9945492SAndroid Build Coastguard Worker #define ALIGN (sizeof(size_t))
6*c9945492SAndroid Build Coastguard Worker #define ONES ((size_t)-1/UCHAR_MAX)
7*c9945492SAndroid Build Coastguard Worker #define HIGHS (ONES * (UCHAR_MAX/2+1))
8*c9945492SAndroid Build Coastguard Worker #define HASZERO(x) ((x)-ONES & ~(x) & HIGHS)
9*c9945492SAndroid Build Coastguard Worker 
__strchrnul(const char * s,int c)10*c9945492SAndroid Build Coastguard Worker char *__strchrnul(const char *s, int c)
11*c9945492SAndroid Build Coastguard Worker {
12*c9945492SAndroid Build Coastguard Worker 	c = (unsigned char)c;
13*c9945492SAndroid Build Coastguard Worker 	if (!c) return (char *)s + strlen(s);
14*c9945492SAndroid Build Coastguard Worker 
15*c9945492SAndroid Build Coastguard Worker #ifdef __GNUC__
16*c9945492SAndroid Build Coastguard Worker 	typedef size_t __attribute__((__may_alias__)) word;
17*c9945492SAndroid Build Coastguard Worker 	const word *w;
18*c9945492SAndroid Build Coastguard Worker 	for (; (uintptr_t)s % ALIGN; s++)
19*c9945492SAndroid Build Coastguard Worker 		if (!*s || *(unsigned char *)s == c) return (char *)s;
20*c9945492SAndroid Build Coastguard Worker 	size_t k = ONES * c;
21*c9945492SAndroid Build Coastguard Worker 	for (w = (void *)s; !HASZERO(*w) && !HASZERO(*w^k); w++);
22*c9945492SAndroid Build Coastguard Worker 	s = (void *)w;
23*c9945492SAndroid Build Coastguard Worker #endif
24*c9945492SAndroid Build Coastguard Worker 	for (; *s && *(unsigned char *)s != c; s++);
25*c9945492SAndroid Build Coastguard Worker 	return (char *)s;
26*c9945492SAndroid Build Coastguard Worker }
27*c9945492SAndroid Build Coastguard Worker 
28*c9945492SAndroid Build Coastguard Worker weak_alias(__strchrnul, strchrnul);
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