Function swap

algorithm/algorithm.c:17–40

static void swap(void *a, void *b, size_t size) {
    switch (size) {
        case 1:  { unsigned char t = *(unsigned char*)a; *(unsigned char*)a = *(unsigned char*)b; *(unsigned char*)b = t; return; }
        case 2:  { unsigned char t[2];  memcpy(t, a, 2);  memcpy(a, b, 2);  memcpy(b, t, 2);  return; }
        case 4:  { unsigned char t[4];  memcpy(t, a, 4);  memcpy(a, b, 4);  memcpy(b, t, 4);  return; }
        case 8:  { unsigned char t[8];  memcpy(t, a, 8);  memcpy(a, b, 8);  memcpy(b, t, 8);  return; }
        case 16: { unsigned char t[16]; memcpy(t, a, 16); memcpy(a, b, 16); memcpy(b, t, 16); return; }
        default: break;
    }

    unsigned char buf[256];
    unsigned char *pa = (unsigned char *)a;
    unsigned char *pb = (unsigned char *)b;
    size_t remaining = size;
    while (remaining > 0) {
        size_t chunk = remaining < sizeof(buf) ? remaining : sizeof(buf);
        memcpy(buf, pa, chunk);
        memcpy(pa, pb, chunk);
        memcpy(pb, buf, chunk);
        pa += chunk;
        pb += chunk;
        remaining -= chunk;
    }
}


static void reverse(void *first, void *last, size_t size) {