path: root/cpukit/score/src/heapgreedy.c

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

/**
 * @file
 *
 * @ingroup RTEMSScoreHeap
 *
 * @brief This source file contains the implementation of
 *   _Heap_Greedy_allocate(), _Heap_Greedy_allocate_all_except_largest(), and
 *   _Heap_Greedy_free().
 */

/*
 * Copyright (c) 2012 embedded brains GmbH & Co. KG
 *
 * 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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <rtems/score/heapimpl.h>

Heap_Block *_Heap_Greedy_allocate(
  Heap_Control *heap,
  const uintptr_t *block_sizes,
  size_t block_count
)
{
  Heap_Block *const free_list_tail = _Heap_Free_list_tail( heap );
  Heap_Block *allocated_blocks = NULL;
  Heap_Block *blocks = NULL;
  Heap_Block *current;
  size_t i;

  _Heap_Protection_free_all_delayed_blocks( heap );

  for (i = 0; i < block_count; ++i) {
    void *next = _Heap_Allocate( heap, block_sizes [i] );

    if ( next != NULL ) {
      Heap_Block *next_block = _Heap_Block_of_alloc_area(
        (uintptr_t) next,
        heap->page_size
      );

      next_block->next = allocated_blocks;
      allocated_blocks = next_block;
    }
  }

  while ( (current = _Heap_Free_list_first( heap )) != free_list_tail ) {
    _Heap_Block_allocate(
      heap,
      current,
      _Heap_Alloc_area_of_block( current ),
      _Heap_Block_size( current ) - HEAP_BLOCK_HEADER_SIZE
    );

    current->next = blocks;
    blocks = current;
  }

  while ( allocated_blocks != NULL ) {
    current = allocated_blocks;
    allocated_blocks = allocated_blocks->next;
    _Heap_Free( heap, (void *) _Heap_Alloc_area_of_block( current ) );
  }

  return blocks;
}

Heap_Block *_Heap_Greedy_allocate_all_except_largest(
  Heap_Control *heap,
  uintptr_t *allocatable_size
)
{
  Heap_Information info;

  _Heap_Get_free_information( heap, &info );

  if ( info.largest > 0 ) {
    *allocatable_size = info.largest - HEAP_BLOCK_HEADER_SIZE + HEAP_ALLOC_BONUS;
  } else {
    *allocatable_size = 0;
  }

  return _Heap_Greedy_allocate( heap, allocatable_size, 1 );
}

void _Heap_Greedy_free(
  Heap_Control *heap,
  Heap_Block *blocks
)
{
  while ( blocks != NULL ) {
    Heap_Block *current = blocks;

    blocks = blocks->next;
    _Heap_Free( heap, (void *) _Heap_Alloc_area_of_block( current ) );
  }
}