snapraid/raid/helper.c

95 lines
1.9 KiB
C
Raw Normal View History

2019-01-07 14:06:15 +01:00
/*
* Copyright (C) 2013 Andrea Mazzoleni
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include "internal.h"
#define RAID_SWAP(a, b) \
do { \
if (v[a] > v[b]) { \
int t = v[a]; \
v[a] = v[b]; \
v[b] = t; \
} \
} while (0)
void raid_sort(int n, int *v)
{
/* sorting networks generated with Batcher's Merge-Exchange */
switch (n) {
case 2:
RAID_SWAP(0, 1);
break;
case 3:
RAID_SWAP(0, 2);
RAID_SWAP(0, 1);
RAID_SWAP(1, 2);
break;
case 4:
RAID_SWAP(0, 2);
RAID_SWAP(1, 3);
RAID_SWAP(0, 1);
RAID_SWAP(2, 3);
RAID_SWAP(1, 2);
break;
case 5:
RAID_SWAP(0, 4);
RAID_SWAP(0, 2);
RAID_SWAP(1, 3);
RAID_SWAP(2, 4);
RAID_SWAP(0, 1);
RAID_SWAP(2, 3);
RAID_SWAP(1, 4);
RAID_SWAP(1, 2);
RAID_SWAP(3, 4);
break;
case 6:
RAID_SWAP(0, 4);
RAID_SWAP(1, 5);
RAID_SWAP(0, 2);
RAID_SWAP(1, 3);
RAID_SWAP(2, 4);
RAID_SWAP(3, 5);
RAID_SWAP(0, 1);
RAID_SWAP(2, 3);
RAID_SWAP(4, 5);
RAID_SWAP(1, 4);
RAID_SWAP(1, 2);
RAID_SWAP(3, 4);
break;
}
}
void raid_insert(int n, int *v, int i)
{
/* we don't use binary search because this is intended */
/* for very small vectors and we want to optimize the case */
/* of elements inserted already in order */
/* insert at the end */
v[n] = i;
/* swap until in the correct position */
while (n > 0 && v[n - 1] > v[n]) {
/* swap */
int t = v[n - 1];
v[n - 1] = v[n];
v[n] = t;
/* previous position */
--n;
}
}