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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.
*
**************************************************************************/
/* Allocator of IDs (e.g. OpenGL object IDs), or simply an allocator of
* numbers.
*
* The allocator uses a bit array to track allocated IDs.
*/
#ifndef U_IDALLOC_H
#define U_IDALLOC_H
#include <inttypes.h>
#include <stdbool.h>
#include "simple_mtx.h"
#include "bitscan.h"
#ifdef __cplusplus
extern "C" {
#endif
struct util_idalloc
{
uint32_t *data;
unsigned num_elements; /* number of allocated elements of "data" */
unsigned num_set_elements; /* the last non-zero element of "data" + 1 */
unsigned lowest_free_idx;
};
void
util_idalloc_init(struct util_idalloc *buf, unsigned initial_num_ids);
void
util_idalloc_fini(struct util_idalloc *buf);
unsigned
util_idalloc_alloc(struct util_idalloc *buf);
unsigned
util_idalloc_alloc_range(struct util_idalloc *buf, unsigned num);
void
util_idalloc_free(struct util_idalloc *buf, unsigned id);
void
util_idalloc_reserve(struct util_idalloc *buf, unsigned id);
#define util_idalloc_foreach(buf, id) \
for (uint32_t _i = 0, id, _count = (buf)->num_set_elements, \
_mask = _count ? (buf)->data[0] : 0; \
_i < _count; _mask = ++_i < _count ? (buf)->data[_i] : 0) \
while (_mask) \
if ((id = _i * 32 + u_bit_scan(&_mask)), true)
/* This allows freeing IDs while iterating, excluding ID=0. */
#define util_idalloc_foreach_no_zero_safe(buf, id) \
for (uint32_t _i = 0, _bit, id, _count = (buf)->num_set_elements, \
_mask = _count ? (buf)->data[0] & ~0x1 : 0; \
_i < _count; _mask = ++_i < _count ? (buf)->data[_i] : 0) \
while (_mask) \
if ((_bit = u_bit_scan(&_mask), id = _i * 32 + _bit), \
(buf)->data[_i] & BITFIELD_BIT(_bit))
/* Thread-safe variant. */
struct util_idalloc_mt {
struct util_idalloc buf;
simple_mtx_t mutex;
bool skip_zero;
};
void
util_idalloc_mt_init(struct util_idalloc_mt *buf,
unsigned initial_num_ids, bool skip_zero);
void
util_idalloc_mt_init_tc(struct util_idalloc_mt *buf);
void
util_idalloc_mt_fini(struct util_idalloc_mt *buf);
unsigned
util_idalloc_mt_alloc(struct util_idalloc_mt *buf);
void
util_idalloc_mt_free(struct util_idalloc_mt *buf, unsigned id);
/* util_idalloc_sparse: The 32-bit ID range is divided into separately managed
* segments. This reduces virtual memory usage when IDs are sparse.
* It's done by layering util_idalloc_sparse on top of util_idalloc.
*
* If the last ID is allocated:
* - "util_idalloc" occupies 512 MB of virtual memory
* - "util_idalloc_sparse" occupies only 512 KB of virtual memory
*/
struct util_idalloc_sparse {
struct util_idalloc segment[1024];
};
#define UTIL_IDALLOC_MAX_IDS_PER_SEGMENT(buf) \
((uint32_t)(BITFIELD64_BIT(32) / ARRAY_SIZE((buf)->segment)))
#define UTIL_IDALLOC_MAX_ELEMS_PER_SEGMENT(buf) \
(UTIL_IDALLOC_MAX_IDS_PER_SEGMENT(buf) / 32)
void
util_idalloc_sparse_init(struct util_idalloc_sparse *buf);
void
util_idalloc_sparse_fini(struct util_idalloc_sparse *buf);
unsigned
util_idalloc_sparse_alloc(struct util_idalloc_sparse *buf);
unsigned
util_idalloc_sparse_alloc_range(struct util_idalloc_sparse *buf, unsigned num);
void
util_idalloc_sparse_free(struct util_idalloc_sparse *buf, unsigned id);
void
util_idalloc_sparse_reserve(struct util_idalloc_sparse *buf, unsigned id);
/* This allows freeing IDs while iterating, excluding ID=0. */
#define util_idalloc_sparse_foreach_no_zero_safe(buf, id) \
for (uint32_t _s = 0; _s < ARRAY_SIZE((buf)->segment); _s++) \
for (uint32_t _i = 0, _bit, id, _count = (buf)->segment[_s].num_set_elements, \
_mask = _count ? (buf)->segment[_s].data[0] & ~0x1 : 0; \
_i < _count; _mask = ++_i < _count ? (buf)->segment[_s].data[_i] : 0) \
while (_mask) \
if ((_bit = u_bit_scan(&_mask), id = _s * UTIL_IDALLOC_MAX_IDS_PER_SEGMENT(buf) + _i * 32 + _bit), \
(buf)->segment[_s].data[_i] & BITFIELD_BIT(_bit))
#ifdef __cplusplus
}
#endif
#endif /* U_IDALLOC_H */
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