cosmopolitan/libc/alg/bisect.h

30 lines
739 B
C

#ifndef COSMOPOLITAN_LIBC_ALG_BISECT_H_
#define COSMOPOLITAN_LIBC_ALG_BISECT_H_
#if !(__ASSEMBLER__ + __LINKER__ + 0)
COSMOPOLITAN_C_START_
forceinline void *bisect(const void *k, const void *data, size_t n, size_t size,
int cmp(const void *a, const void *b, void *arg),
void *arg) {
int dir;
const char *p, *pos;
p = data;
while (n > 0) {
pos = p + size * (n / 2);
dir = cmp(k, pos, arg);
if (dir < 0) {
n /= 2;
} else if (dir > 0) {
p = pos + size;
n -= n / 2 + 1;
} else {
return (void *)pos;
}
}
return NULL;
}
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* COSMOPOLITAN_LIBC_ALG_BISECT_H_ */