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153 lines
3.5 KiB
C
153 lines
3.5 KiB
C
/*
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* bitmap.h: Simple bitmap operations
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*
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* Copyright (C) 2010 Red Hat, Inc.
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* Copyright (C) 2010 Novell, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Author: Jim Fehlig <jfehlig@novell.com>
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*/
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#include <config.h>
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#include <limits.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include "bitmap.h"
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#include "memory.h"
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struct _virBitmap {
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size_t size;
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uint32_t *map;
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};
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#define VIR_BITMAP_BITS_PER_UNIT (sizeof(uint32_t) * CHAR_BIT)
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#define VIR_BITMAP_UNIT_OFFSET(b) ((b) / VIR_BITMAP_BITS_PER_UNIT)
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#define VIR_BITMAP_BIT_OFFSET(b) ((b) % VIR_BITMAP_BITS_PER_UNIT)
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/**
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* virBitmapAlloc:
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* @size: number of bits
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*
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* Allocate a bitmap capable of containing @size bits.
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*
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* Returns a pointer to the allocated bitmap or NULL if
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* memory cannot be allocated.
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*/
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virBitmapPtr virBitmapAlloc(size_t size)
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{
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virBitmapPtr bitmap;
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size_t sz;
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if (SIZE_MAX - VIR_BITMAP_BITS_PER_UNIT < size || size == 0)
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return NULL;
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sz = (size + VIR_BITMAP_BITS_PER_UNIT - 1) /
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VIR_BITMAP_BITS_PER_UNIT;
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if (VIR_ALLOC(bitmap) < 0)
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return NULL;
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if (VIR_ALLOC_N(bitmap->map, sz) < 0) {
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VIR_FREE(bitmap);
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return NULL;
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}
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return bitmap;
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}
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/**
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* virBitmapFree:
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* @bitmap: previously allocated bitmap
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*
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* Free @bitmap previously allocated by virBitmapAlloc.
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*/
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void virBitmapFree(virBitmapPtr bitmap)
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{
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if (bitmap) {
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VIR_FREE(bitmap->map);
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VIR_FREE(bitmap);
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}
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}
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/**
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* virBitmapSetBit:
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* @bitmap: Pointer to bitmap
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* @b: bit position to set
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*
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* Set bit position @b in @bitmap
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*
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* Returns 0 on if bit is successfully set, -1 on error.
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*/
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int virBitmapSetBit(virBitmapPtr bitmap, size_t b)
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{
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if (bitmap->size <= b)
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return -1;
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bitmap->map[VIR_BITMAP_UNIT_OFFSET(b)] |= (1 << VIR_BITMAP_BIT_OFFSET(b));
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return 0;
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}
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/**
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* virBitmapClearBit:
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* @bitmap: Pointer to bitmap
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* @b: bit position to clear
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*
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* Clear bit position @b in @bitmap
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*
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* Returns 0 on if bit is successfully clear, -1 on error.
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*/
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int virBitmapClearBit(virBitmapPtr bitmap, size_t b)
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{
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if (bitmap->size <= b)
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return -1;
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bitmap->map[VIR_BITMAP_UNIT_OFFSET(b)] &= ~(1 << VIR_BITMAP_BIT_OFFSET(b));
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return 0;
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}
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/**
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* virBitmapGetBit:
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* @bitmap: Pointer to bitmap
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* @b: bit position to get
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* @result: bool pointer to receive bit setting
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*
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* Get setting of bit position @b in @bitmap and store in @result
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*
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* On success, @result will contain the setting of @b and 0 is
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* returned. On failure, -1 is returned and @result is unchanged.
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*/
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int virBitmapGetBit(virBitmapPtr bitmap, size_t b, bool *result)
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{
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uint32_t bit;
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if (bitmap->size <= b)
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return -1;
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bit = bitmap->map[VIR_BITMAP_UNIT_OFFSET(b)] &
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(1 << VIR_BITMAP_BIT_OFFSET(b));
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*result = bit != 0;
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return 0;
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}
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