/* SPDX-License-Identifier: BSD-2-Clause */

/**
 * @file
 *
 * @ingroup rtems_rtl
 *
 * @brief RTEMS Run-Time Linker Bit Allocator Header
 */

/*
 *  COPYRIGHT (c) 2019 Chris Johns <chrisj@rtems.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.
 */

#if !defined (_RTEMS_RTL_BIT_ALLOC_H_)
#define _RTEMS_RTL_BIT_ALLOC_H_

#include <rtems/rtl/rtl-fwd.h>
#include <rtems/rtl/rtl-obj-fwd.h>

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

/**
 * Bit Allocator data
 */
typedef struct rtems_rtl_bit_alloc
{
  uint8_t*  base;       /**< The memory being allocated. */
  size_t    size;       /**< The number of bytes of memory being managed. */
  uint32_t* bits;       /**< The bit map indicating which blocks are allocated. */
  size_t    block_size; /**< The size of a block, the minimum allocation unit. */
  size_t    blocks;     /**< The number of blocks in the memory. */
} rtems_rtl_bit_alloc;

/**
 * Open a bit allocator. The allocator allocates block_size pieces of the memory
 * being managed.
 *
 * @param base The memory to managem NULL to allocate a piece of memory.
 * @param size The size of the memory being managed in bytes.
 * @param block_size The minimum allocation unit in bytes.
 * @param used The amount of memory already in use in bytes.
 * @retval rtems_rtl_bit_alloc The bit allocator structure.
 */
rtems_rtl_bit_alloc* rtems_rtl_bit_alloc_open (void*  base,
                                               size_t size,
                                               size_t block_size,
                                               size_t used);

/**
 * Close the bit allocator.
 *
 * @param balloc The allocator to close.
 */

void rtems_rtl_bit_alloc_close (rtems_rtl_bit_alloc* balloc);

/**
 * Allocate a piece of memory being managed. The size is in bytes are is rounded
 * up the next block size.
 *
 * @param balloc The allocator.
 * @param size Number of bytes to allocate.
 * @return void* The memory if the allocation is successful else NULL if there
 *               is no more memory.
 */
void* rtems_rtl_bit_alloc_balloc (rtems_rtl_bit_alloc* balloc, size_t size);

/**
 * Free an allocated memory block. The size is required because the allocator does not
 * contain any state information.
 */
void rtems_rtl_bit_alloc_bfree (rtems_rtl_bit_alloc* balloc, void* addr, size_t size);

#ifdef __cplusplus
}
#endif /* __cplusplus */

#endif