#include <u.h>
#include <libc.h>
#include "runecompose.h"

/* assume 16-bit runes! */
static uint*
bsearchi(uint c, uint *t, int n, int ne)
{
	uint *p;
	int m;

	while(n > 1) {
		m = n/2;
		p = t + m*ne;
		if(c >= p[0]) {
			t = p;
			n = n-m;
		} else
			n = m;
	}
	if(n && c == t[0])
		return t;
	return 0;
}

int
runecompose(Rune b, Rune c)
{
	uint *p;

	p = bsearchi(b<<16 | c, __combine2, nelem(__combine2)/2, 2);
	if(p)
		return p[1];
	return -1;
}