rotate.c


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22

#include <stddef.h>

#include "common.h"
#include "counts.h"

/* rotates left */
void rotate(char *base, size_t size, size_t shift)
{
	int dir = 1;

	counts[CURRENT].rotate++;
	while (shift) {
		while (2*shift <= size) {
			swap(base, base + dir*shift, shift);
			size -= shift;
			base += shift*dir;
		}
		shift = size - shift;
		base  = dir > 0 ? base + size - shift : base - shift;
		dir  *= -1;
	}
}