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/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA */
/*
Handling of uchar arrays as large bitmaps.
We assume that the size of the used bitmap is less than ~(uint) 0
TODO:
create an unique structure for this that includes the mutex and bitmap size
make a init function that will allocate the bitmap and init the mutex
make an end function that will free everything
*/
#include "mysys_priv.h"
#include <my_bitmap.h>
pthread_mutex_t LOCK_bitmap;
void bitmap_set_bit(uchar *bitmap, uint bitmap_size, uint bitmap_bit)
{
if (bitmap_bit < bitmap_size*8)
{
pthread_mutex_lock(&LOCK_bitmap);
bitmap[bitmap_bit / 8] |= (1 << (bitmap_bit & 7));
pthread_mutex_unlock(&LOCK_bitmap);
}
}
uint bitmap_set_next(uchar *bitmap, uint bitmap_size)
{
uint bit_found = MY_BIT_NONE;
uint i;
pthread_mutex_lock(&LOCK_bitmap);
for (i=0; i < bitmap_size ; i++, bitmap++)
{
if (*bitmap != 0xff)
{ /* Found slot with free bit */
uint b;
for (b=0; ; b++)
{
if (!(*bitmap & (1 << b)))
{
*bitmap |= 1<<b;
bit_found = (i*8)+b;
break;
}
}
break; /* Found bit */
}
}
pthread_mutex_unlock(&LOCK_bitmap);
return bit_found;
}
void bitmap_clear_bit(uchar *bitmap, uint bitmap_size, uint bitmap_bit)
{
if (bitmap_bit < bitmap_size*8)
{
pthread_mutex_lock(&LOCK_bitmap);
bitmap[bitmap_bit / 8] &= ~ (1 << (bitmap_bit & 7));
pthread_mutex_unlock(&LOCK_bitmap);
}
}
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