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/**************************************************************************
*
* Copyright 2017 Valve Corporation
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
**************************************************************************/
/**
* @file
* A simple allocator that allocates and release "numbers".
*
* @author Samuel Pitoiset <samuel.pitoiset@gmail.com>
*/
#include "util/u_idalloc.h"
#include "util/u_math.h"
#include <stdlib.h>
void
util_idalloc_init(struct util_idalloc *buf)
{
memset(buf, 0, sizeof(*buf));
}
void
util_idalloc_fini(struct util_idalloc *buf)
{
if (buf->data)
free(buf->data);
}
void
util_idalloc_resize(struct util_idalloc *buf, unsigned new_num_elements)
{
new_num_elements = align(new_num_elements, 32);
if (new_num_elements > buf->num_elements) {
unsigned i;
buf->data = realloc(buf->data,
(new_num_elements / 32) * sizeof(*buf->data));
for (i = buf->num_elements / 32; i < new_num_elements / 32; i++)
buf->data[i] = 0;
buf->num_elements = new_num_elements;
}
}
unsigned
util_idalloc_alloc(struct util_idalloc *buf)
{
unsigned num_elements = buf->num_elements;
for (unsigned i = 0; i < num_elements / 32; i++) {
if (buf->data[i] == 0xffffffff)
continue;
unsigned bit = ffs(~buf->data[i]) - 1;
buf->data[i] |= 1u << bit;
return i * 32 + bit;
}
/* No slots available, resize and return the first free. */
util_idalloc_resize(buf, num_elements * 2);
buf->data[num_elements / 32] |= 1 << (num_elements % 32);
return num_elements;
}
void
util_idalloc_free(struct util_idalloc *buf, unsigned id)
{
assert(id < buf->num_elements);
buf->data[id / 32] &= ~(1 << (id % 32));
}
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