30 lines
739 B
C
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_ */
|