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/*
* strspn, strcspn
*/
#include <string.h>
#include <stddef.h>
#include <inttypes.h>
#include <limits.h>
#ifndef LONG_BIT
#define LONG_BIT (CHAR_BIT*sizeof(long))
#endif
static void set_bit(unsigned long *bitmap, unsigned int bit)
{
bitmap[bit / LONG_BIT] |= 1UL << (bit % LONG_BIT);
}
static int test_bit(unsigned long *bitmap, unsigned int bit)
{
return (int)(bitmap[bit / LONG_BIT] >> (bit % LONG_BIT)) & 1;
}
static size_t strxspn(const char *s, const char *map, int parity)
{
unsigned long matchmap[((1 << CHAR_BIT) + LONG_BIT - 1) / LONG_BIT];
size_t n = 0;
/* Create bitmap */
memset(matchmap, 0, sizeof matchmap);
while (*map)
set_bit(matchmap, (unsigned char)*map++);
/* Make sure the null character never matches */
if (parity)
set_bit(matchmap, 0);
/* Calculate span length */
while (test_bit(matchmap, (unsigned char)*s++) ^ parity)
n++;
return n;
}
size_t strspn(const char *s, const char *accept)
{
return strxspn(s, accept, 0);
}
size_t strcspn(const char *s, const char *reject)
{
return strxspn(s, reject, 1);
}
char *strpbrk(const char *s, const char *accept)
{
const char *ss = s + strxspn(s, accept, 1);
return *ss ? (char *)ss : NULL;
}
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