From 0b44a0315b47dd8eced9f3b7f31580cf14bbfc01 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sat, 12 Feb 2011 00:22:29 -0500 Subject: initial check-in, version 0.5.0 --- src/string/strspn.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) create mode 100644 src/string/strspn.c (limited to 'src/string/strspn.c') diff --git a/src/string/strspn.c b/src/string/strspn.c new file mode 100644 index 00000000..59b063e5 --- /dev/null +++ b/src/string/strspn.c @@ -0,0 +1,22 @@ +#include + +#define BITOP(a,b,op) \ + ((a)[(size_t)(b)/(8*sizeof *(a))] op (size_t)1<<((size_t)(b)%(8*sizeof *(a)))) + +size_t strspn(const char *_s, const char *_c) +{ + const unsigned char *s = _s; + const unsigned char *c = _c; + const unsigned char *a = s; + size_t byteset[32/sizeof(size_t)] = { 0 }; + + if (!c[0]) return 0; + if (!c[1]) { + for (; *s == *c; s++); + return s-a; + } + + for (; *c && BITOP(byteset, *c, |=); c++); + for (; *s && BITOP(byteset, *s, &); s++); + return s-a; +} -- cgit v1.2.1