/*
* Copyright (C) 2006 Jakub Jermar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @file bitmap.c
* @brief Implementation of bitmap ADT.
*
* This file implements bitmap ADT and provides functions for
* setting and clearing ranges of bits.
*/
#include <adt/bitmap.h>
#include <typedefs.h>
#include <arch/types.h>
#include <align.h>
#include <debug.h>
#include <macros.h>
#define ALL_ONES 0xff
#define ALL_ZEROES 0x00
/** Initialize bitmap.
*
* No portion of the bitmap is set or cleared by this function.
*
* @param bitmap Bitmap structure.
* @param map Address of the memory used to hold the map.
* @param bits Number of bits stored in bitmap.
*/
void bitmap_initialize(bitmap_t *bitmap, __u8 *map, count_t bits)
{
bitmap->map = map;
bitmap->bits = bits;
}
/** Set range of bits.
*
* @param bitmap Bitmap structure.
* @param start Starting bit.
* @param bits Number of bits to set.
*/
void bitmap_set_range(bitmap_t *bitmap, index_t start, count_t bits)
{
index_t i=0;
index_t aligned_start;
count_t lub; /* leading unaligned bits */
count_t amb; /* aligned middle bits */
count_t tab; /* trailing aligned bits */
ASSERT(start + bits <= bitmap->bits);
aligned_start = ALIGN_UP(start, 8);
lub = min(aligned_start - start, bits);
amb = bits > lub ? bits - lub : 0;
tab = amb % 8;
if ( start + bits < aligned_start ) {
/*
* Set bits in the middle of byte
*/
bitmap->map[start / 8] |= ((1 << lub)-1) << (start&7);
return;
}
if (lub) {
/*
* Make sure to set any leading unaligned bits.
*/
bitmap->map[start / 8] |= ~((1 << (8 - lub)) - 1);
}
for (i = 0; i < amb / 8; i++) {
/*
* The middle bits can be set byte by byte.
*/
bitmap->map[aligned_start / 8 + i] = ALL_ONES;
}
if (tab) {
/*
* Make sure to set any trailing aligned bits.
*/
bitmap->map[aligned_start / 8 + i] |= (1 << tab) - 1;
}
}
/** Clear range of bits.
*
* @param bitmap Bitmap structure.
* @param start Starting bit.
* @param bits Number of bits to clear.
*/
void bitmap_clear_range(bitmap_t *bitmap, index_t start, count_t bits)
{
index_t i=0;
index_t aligned_start;
count_t lub; /* leading unaligned bits */
count_t amb; /* aligned middle bits */
count_t tab; /* trailing aligned bits */
ASSERT(start + bits <= bitmap->bits);
aligned_start = ALIGN_UP(start, 8);
lub = min(aligned_start - start, bits);
amb = bits > lub ? bits - lub : 0;
tab = amb % 8;
if ( start + bits < aligned_start )
{
/*
* Set bits in the middle of byte
*/
bitmap->map[start / 8] &= ~(((1 << lub)-1) << (start&7));
return;
}
if (lub) {
/*
* Make sure to clear any leading unaligned bits.
*/
bitmap->map[start / 8] &= (1 << (8 - lub)) - 1;
}
for (i = 0; i < amb / 8; i++) {
/*
* The middle bits can be cleared byte by byte.
*/
bitmap->map[aligned_start / 8 + i] = ALL_ZEROES;
}
if (tab) {
/*
* Make sure to clear any trailing aligned bits.
*/
bitmap->map[aligned_start / 8 + i] &= ~((1 << tab) - 1);
}
}
/** Copy portion of one bitmap into another bitmap.
*
* @param dst Destination bitmap.
* @param src Source bitmap.
* @param bits Number of bits to copy.
*/
void bitmap_copy(bitmap_t *dst, bitmap_t *src, count_t bits)
{
index_t i;
ASSERT(bits <= dst->bits);
ASSERT(bits <= src->bits);
for (i = 0; i < bits / 8; i++)
dst->map[i] = src->map[i];
if (bits % 8) {
bitmap_clear_range(dst, i * 8, bits % 8);
dst->map[i] |= src->map[i] & ((1 << (bits % 8)) - 1);
}
}