libvirt/src/util/bitmap.c

198 lines
4.4 KiB
C
Raw Normal View History

/*
* bitmap.h: Simple bitmap operations
*
* Copyright (C) 2010-2011 Red Hat, Inc.
* Copyright (C) 2010 Novell, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; If not, see
* <http://www.gnu.org/licenses/>.
*
* Author: Jim Fehlig <jfehlig@novell.com>
*/
#include <config.h>
#include <limits.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include "bitmap.h"
#include "memory.h"
#include "buf.h"
struct _virBitmap {
size_t max_bit;
size_t map_len;
unsigned long *map;
};
#define VIR_BITMAP_BITS_PER_UNIT ((int) sizeof(unsigned long) * CHAR_BIT)
#define VIR_BITMAP_UNIT_OFFSET(b) ((b) / VIR_BITMAP_BITS_PER_UNIT)
#define VIR_BITMAP_BIT_OFFSET(b) ((b) % VIR_BITMAP_BITS_PER_UNIT)
#define VIR_BITMAP_BIT(b) (1UL << VIR_BITMAP_BIT_OFFSET(b))
/**
* virBitmapNew:
* @size: number of bits
*
* Allocate a bitmap capable of containing @size bits.
*
* Returns a pointer to the allocated bitmap or NULL if
* memory cannot be allocated.
*/
virBitmapPtr virBitmapNew(size_t size)
{
virBitmapPtr bitmap;
size_t sz;
if (SIZE_MAX - VIR_BITMAP_BITS_PER_UNIT < size || size == 0)
return NULL;
sz = (size + VIR_BITMAP_BITS_PER_UNIT - 1) /
VIR_BITMAP_BITS_PER_UNIT;
if (VIR_ALLOC(bitmap) < 0)
return NULL;
if (VIR_ALLOC_N(bitmap->map, sz) < 0) {
VIR_FREE(bitmap);
return NULL;
}
bitmap->max_bit = size;
bitmap->map_len = sz;
return bitmap;
}
/**
* virBitmapFree:
* @bitmap: previously allocated bitmap
*
* Free @bitmap previously allocated by virBitmapNew.
*/
void virBitmapFree(virBitmapPtr bitmap)
{
if (bitmap) {
VIR_FREE(bitmap->map);
VIR_FREE(bitmap);
}
}
int virBitmapCopy(virBitmapPtr dst, virBitmapPtr src)
{
if (dst->max_bit != src->max_bit) {
errno = EINVAL;
return -1;
}
memcpy(dst->map, src->map, src->map_len * sizeof(src->map[0]));
return 0;
}
/**
* virBitmapSetBit:
* @bitmap: Pointer to bitmap
* @b: bit position to set
*
* Set bit position @b in @bitmap
*
* Returns 0 on if bit is successfully set, -1 on error.
*/
int virBitmapSetBit(virBitmapPtr bitmap, size_t b)
{
if (bitmap->max_bit <= b)
return -1;
bitmap->map[VIR_BITMAP_UNIT_OFFSET(b)] |= VIR_BITMAP_BIT(b);
return 0;
}
/**
* virBitmapClearBit:
* @bitmap: Pointer to bitmap
* @b: bit position to clear
*
* Clear bit position @b in @bitmap
*
* Returns 0 on if bit is successfully clear, -1 on error.
*/
int virBitmapClearBit(virBitmapPtr bitmap, size_t b)
{
if (bitmap->max_bit <= b)
return -1;
bitmap->map[VIR_BITMAP_UNIT_OFFSET(b)] &= ~VIR_BITMAP_BIT(b);
return 0;
}
/**
* virBitmapGetBit:
* @bitmap: Pointer to bitmap
* @b: bit position to get
* @result: bool pointer to receive bit setting
*
* Get setting of bit position @b in @bitmap and store in @result
*
* On success, @result will contain the setting of @b and 0 is
* returned. On failure, -1 is returned and @result is unchanged.
*/
int virBitmapGetBit(virBitmapPtr bitmap, size_t b, bool *result)
{
if (bitmap->max_bit <= b)
return -1;
*result = !!(bitmap->map[VIR_BITMAP_UNIT_OFFSET(b)] & VIR_BITMAP_BIT(b));
return 0;
}
/**
* virBitmapString:
* @bitmap: Pointer to bitmap
*
* Convert @bitmap to printable string.
*
* Returns pointer to the string or NULL on error.
*/
char *virBitmapString(virBitmapPtr bitmap)
{
virBuffer buf = VIR_BUFFER_INITIALIZER;
size_t sz;
virBufferAddLit(&buf, "0x");
sz = bitmap->map_len;
while (sz--) {
virBufferAsprintf(&buf, "%0*lx",
VIR_BITMAP_BITS_PER_UNIT / 4,
bitmap->map[sz]);
}
if (virBufferError(&buf)) {
virBufferFreeAndReset(&buf);
return NULL;
}
return virBufferContentAndReset(&buf);
}