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/**
* @file
*
* @ingroup ScoreHeap
*
* @brief Heap Handler implementation.
*/
/*
* COPYRIGHT (c) 1989-1999.
* On-Line Applications Research Corporation (OAR).
*
* Copyright (c) 2010 embedded brains GmbH.
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* $Id$
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/system.h>
#include <rtems/score/sysstate.h>
#include <rtems/score/heap.h>
static void _Heap_Free_block( Heap_Control *heap, Heap_Block *block )
{
Heap_Statistics *const stats = &heap->stats;
/* Statistics */
++stats->used_blocks;
--stats->frees;
_Heap_Free( heap, (void *) _Heap_Alloc_area_of_block( block ));
}
static void _Heap_Merge_below(
Heap_Control *heap,
uintptr_t extend_area_begin,
Heap_Block *first_block
)
{
uintptr_t const page_size = heap->page_size;
uintptr_t const new_first_block_alloc_begin =
_Heap_Align_up( extend_area_begin + HEAP_BLOCK_HEADER_SIZE, page_size );
uintptr_t const new_first_block_begin =
new_first_block_alloc_begin - HEAP_BLOCK_HEADER_SIZE;
uintptr_t const first_block_begin = (uintptr_t) first_block;
uintptr_t const new_first_block_size =
first_block_begin - new_first_block_begin;
Heap_Block *const new_first_block = (Heap_Block *) new_first_block_begin;
new_first_block->prev_size = first_block->prev_size;
new_first_block->size_and_flag = new_first_block_size | HEAP_PREV_BLOCK_USED;
_Heap_Free_block( heap, new_first_block );
}
static void _Heap_Merge_above(
Heap_Control *heap,
Heap_Block *last_block,
uintptr_t extend_area_end
)
{
uintptr_t const page_size = heap->page_size;
uintptr_t const last_block_begin = (uintptr_t) last_block;
uintptr_t const last_block_new_size = _Heap_Align_down(
extend_area_end - last_block_begin - HEAP_BLOCK_HEADER_SIZE,
page_size
);
Heap_Block *const new_last_block =
_Heap_Block_at( last_block, last_block_new_size );
new_last_block->size_and_flag =
(last_block->size_and_flag - last_block_new_size)
| HEAP_PREV_BLOCK_USED;
_Heap_Block_set_size( last_block, last_block_new_size );
_Heap_Free_block( heap, last_block );
}
static void _Heap_Link_below(
Heap_Block *link,
Heap_Block *last_block
)
{
uintptr_t const last_block_begin = (uintptr_t) last_block;
uintptr_t const link_begin = (uintptr_t) link;
last_block->size_and_flag =
(link_begin - last_block_begin) | HEAP_PREV_BLOCK_USED;
}
static void _Heap_Link_above(
Heap_Block *link,
Heap_Block *first_block,
Heap_Block *last_block
)
{
uintptr_t const link_begin = (uintptr_t) link;
uintptr_t const first_block_begin = (uintptr_t) first_block;
_Heap_Block_set_size( link, first_block_begin - link_begin );
last_block->size_and_flag |= HEAP_PREV_BLOCK_USED;
}
bool _Heap_Extend(
Heap_Control *heap,
void *extend_area_begin_ptr,
uintptr_t extend_area_size,
uintptr_t *extended_size_ptr
)
{
Heap_Statistics *const stats = &heap->stats;
Heap_Block *const first_block = heap->first_block;
Heap_Block *start_block = first_block;
Heap_Block *merge_below_block = NULL;
Heap_Block *merge_above_block = NULL;
Heap_Block *link_below_block = NULL;
Heap_Block *link_above_block = NULL;
Heap_Block *extend_first_block = NULL;
Heap_Block *extend_last_block = NULL;
uintptr_t const page_size = heap->page_size;
uintptr_t const min_block_size = heap->min_block_size;
uintptr_t const extend_area_begin = (uintptr_t) extend_area_begin_ptr;
uintptr_t const extend_area_end = extend_area_begin + extend_area_size;
uintptr_t const free_size = stats->free_size;
uintptr_t extend_first_block_size = 0;
uintptr_t extended_size = 0;
bool extend_area_ok = false;
if ( extend_area_end < extend_area_begin ) {
return false;
}
extend_area_ok = _Heap_Get_first_and_last_block(
extend_area_begin,
extend_area_size,
page_size,
min_block_size,
&extend_first_block,
&extend_last_block
);
if (!extend_area_ok ) {
/* For simplicity we reject extend areas that are too small */
return false;
}
do {
uintptr_t const sub_area_begin = (start_block != first_block) ?
(uintptr_t) start_block : heap->area_begin;
uintptr_t const sub_area_end = start_block->prev_size;
Heap_Block *const end_block =
_Heap_Block_of_alloc_area( sub_area_end, page_size );
if (
sub_area_end > extend_area_begin && extend_area_end > sub_area_begin
) {
return false;
}
if ( extend_area_end == sub_area_begin ) {
merge_below_block = start_block;
} else if ( extend_area_end < sub_area_end ) {
link_below_block = start_block;
}
if ( sub_area_end == extend_area_begin ) {
start_block->prev_size = extend_area_end;
merge_above_block = end_block;
} else if ( sub_area_end < extend_area_begin ) {
link_above_block = end_block;
}
start_block = _Heap_Block_at( end_block, _Heap_Block_size( end_block ) );
} while ( start_block != first_block );
if ( extend_area_begin < heap->area_begin ) {
heap->area_begin = extend_area_begin;
} else if ( heap->area_end < extend_area_end ) {
heap->area_end = extend_area_end;
}
extend_first_block_size =
(uintptr_t) extend_last_block - (uintptr_t) extend_first_block;
extend_first_block->prev_size = extend_area_end;
extend_first_block->size_and_flag =
extend_first_block_size | HEAP_PREV_BLOCK_USED;
_Heap_Protection_block_initialize( heap, extend_first_block );
extend_last_block->prev_size = extend_first_block_size;
extend_last_block->size_and_flag = 0;
_Heap_Protection_block_initialize( heap, extend_last_block );
if ( (uintptr_t) extend_first_block < (uintptr_t) heap->first_block ) {
heap->first_block = extend_first_block;
} else if ( (uintptr_t) extend_last_block > (uintptr_t) heap->last_block ) {
heap->last_block = extend_last_block;
}
if ( merge_below_block != NULL ) {
_Heap_Merge_below( heap, extend_area_begin, merge_below_block );
} else if ( link_below_block != NULL ) {
_Heap_Link_below(
link_below_block,
extend_last_block
);
}
if ( merge_above_block != NULL ) {
_Heap_Merge_above( heap, merge_above_block, extend_area_end );
} else if ( link_above_block != NULL ) {
_Heap_Link_above(
link_above_block,
extend_first_block,
extend_last_block
);
}
if ( merge_below_block == NULL && merge_above_block == NULL ) {
_Heap_Free_block( heap, extend_first_block );
}
_Heap_Set_last_block_size( heap );
extended_size = stats->free_size - free_size;
/* Statistics */
stats->size += extended_size;
if ( extended_size_ptr != NULL )
*extended_size_ptr = extended_size;
return true;
}
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