static void test_check_free_block(void)
{
Heap_Block *block = NULL;
Heap_Block *next_block = NULL;
Heap_Block *first_free_block = NULL;
Heap_Block *secound_free_block = NULL;
void *p1 = NULL;
puts( "test the _Heap_Walk_check_free_block() function" );
puts( "\tset a previous size for the next block which is not equal to the size of the actual block" );
test_heap_init_default();
block = _Heap_Free_list_first( &TestHeap );
next_block = _Heap_Block_at( block, _Heap_Block_size( block ) );
next_block->prev_size = _Heap_Block_size( block ) - 1;
test_call_heap_walk( false );
puts( "\tclear the previous_used flag of the first free block after an used block" );
test_heap_init_default();
p1 = test_allocate_block();
block = _Heap_Block_of_alloc_area( (uintptr_t) p1, TestHeap.page_size );
first_free_block = _Heap_Free_list_first( &TestHeap );
first_free_block->size_and_flag &= ~HEAP_PREV_BLOCK_USED;
first_free_block->prev_size = _Heap_Block_size( block );
_Heap_Free_list_insert_after( first_free_block, block );
test_call_heap_walk( false );
puts( "\ttake a free block out of the free list" );
test_heap_init_custom();
test_create_heap_with_gaps();
first_free_block = _Heap_Free_list_first( &TestHeap );
secound_free_block = first_free_block->next;
_Heap_Free_list_remove( secound_free_block );
test_call_heap_walk( false );
}
static Heap_Block *_Heap_Block_allocate_from_end(
Heap_Control *heap,
Heap_Block *block,
Heap_Block *free_list_anchor,
uintptr_t alloc_begin,
uintptr_t alloc_size
)
{
Heap_Statistics *const stats = &heap->stats;
uintptr_t block_begin = (uintptr_t) block;
uintptr_t block_size = _Heap_Block_size( block );
uintptr_t block_end = block_begin + block_size;
Heap_Block *const new_block =
_Heap_Block_of_alloc_area( alloc_begin, heap->page_size );
uintptr_t const new_block_begin = (uintptr_t) new_block;
uintptr_t const new_block_size = block_end - new_block_begin;
block_end = new_block_begin;
block_size = block_end - block_begin;
_HAssert( block_size >= heap->min_block_size );
_HAssert( new_block_size >= heap->min_block_size );
/* Statistics */
stats->free_size += block_size;
if ( _Heap_Is_prev_used( block ) ) {
_Heap_Free_list_insert_after( free_list_anchor, block );
free_list_anchor = block;
/* Statistics */
++stats->free_blocks;
} else {
Heap_Block *const prev_block = _Heap_Prev_block( block );
uintptr_t const prev_block_size = _Heap_Block_size( prev_block );
block = prev_block;
block_begin = (uintptr_t) block;
block_size += prev_block_size;
}
block->size_and_flag = block_size | HEAP_PREV_BLOCK_USED;
new_block->prev_size = block_size;
new_block->size_and_flag = new_block_size;
_Heap_Block_split( heap, new_block, free_list_anchor, alloc_size );
return new_block;
}
static void test_check_free_list(void)
{
void *p1 = NULL;
Heap_Block *first_free_block = NULL;
Heap_Block *secound_free_block = NULL;
Heap_Block *third_free_block = NULL;
Heap_Block *used_block = NULL;
puts( "testing the _Heap_Walk_check_free_list() function" );
puts( "\tno free blocks" );
test_heap_init_custom();
test_fill_heap();
test_call_heap_walk( true );
puts( "\tcreate a loop in the free list" );
test_heap_init_default();
test_create_heap_with_gaps();
/* find free blocks */
first_free_block = _Heap_Free_list_first( &TestHeap );
secound_free_block = first_free_block->next;
third_free_block = secound_free_block->next;
/* create a loop */
third_free_block->next = secound_free_block;
secound_free_block->prev = third_free_block;
test_call_heap_walk( false );
puts( "\tput a block outside the heap to the free list" );
test_heap_init_default();
first_free_block = _Heap_Free_list_first( &TestHeap );
first_free_block->next = TestHeap.first_block - 1;
test_call_heap_walk( false );
puts( "\tput a block on the free list, which is not page-aligned" );
test_heap_init_custom();
test_create_heap_with_gaps();
first_free_block = _Heap_Free_list_first( &TestHeap );
first_free_block->next = (Heap_Block *) ((uintptr_t) first_free_block->next + CPU_ALIGNMENT);
first_free_block->next->prev = first_free_block;
test_call_heap_walk( false );
puts( "\tput a used block on the free list" );
test_heap_init_custom();
test_create_heap_with_gaps();
p1 = test_allocate_block();
first_free_block = _Heap_Free_list_first( &TestHeap );
used_block = _Heap_Block_of_alloc_area( (uintptr_t) p1, TestHeap.page_size );
_Heap_Free_list_insert_after( first_free_block, used_block );
test_call_heap_walk( false );
}
bool _Heap_Free( Heap_Control *heap, void *alloc_begin_ptr )
{
Heap_Statistics *const stats = &heap->stats;
uintptr_t alloc_begin = (uintptr_t) alloc_begin_ptr;
Heap_Block *block =
_Heap_Block_of_alloc_area( alloc_begin, heap->page_size );
Heap_Block *next_block = NULL;
uintptr_t block_size = 0;
uintptr_t next_block_size = 0;
bool next_is_free = false;
if ( !_Heap_Is_block_in_heap( heap, block ) ) {
return false;
}
block_size = _Heap_Block_size( block );
next_block = _Heap_Block_at( block, block_size );
if ( !_Heap_Is_block_in_heap( heap, next_block ) ) {
_HAssert( false );
return false;
}
if ( !_Heap_Is_prev_used( next_block ) ) {
_HAssert( false );
return false;
}
next_block_size = _Heap_Block_size( next_block );
next_is_free = next_block != heap->last_block
&& !_Heap_Is_prev_used( _Heap_Block_at( next_block, next_block_size ));
if ( !_Heap_Is_prev_used( block ) ) {
uintptr_t const prev_size = block->prev_size;
Heap_Block * const prev_block = _Heap_Block_at( block, -prev_size );
if ( !_Heap_Is_block_in_heap( heap, prev_block ) ) {
_HAssert( false );
return( false );
}
/* As we always coalesce free blocks, the block that preceedes prev_block
must have been used. */
if ( !_Heap_Is_prev_used ( prev_block) ) {
_HAssert( false );
return( false );
}
if ( next_is_free ) { /* coalesce both */
uintptr_t const size = block_size + prev_size + next_block_size;
_Heap_Free_list_remove( next_block );
stats->free_blocks -= 1;
prev_block->size_and_flag = size | HEAP_PREV_BLOCK_USED;
next_block = _Heap_Block_at( prev_block, size );
_HAssert(!_Heap_Is_prev_used( next_block));
next_block->prev_size = size;
} else { /* coalesce prev */
uintptr_t const size = block_size + prev_size;
prev_block->size_and_flag = size | HEAP_PREV_BLOCK_USED;
next_block->size_and_flag &= ~HEAP_PREV_BLOCK_USED;
next_block->prev_size = size;
}
} else if ( next_is_free ) { /* coalesce next */
uintptr_t const size = block_size + next_block_size;
_Heap_Free_list_replace( next_block, block );
block->size_and_flag = size | HEAP_PREV_BLOCK_USED;
next_block = _Heap_Block_at( block, size );
next_block->prev_size = size;
} else { /* no coalesce */
/* Add 'block' to the head of the free blocks list as it tends to
produce less fragmentation than adding to the tail. */
_Heap_Free_list_insert_after( _Heap_Free_list_head( heap), block );
block->size_and_flag = block_size | HEAP_PREV_BLOCK_USED;
next_block->size_and_flag &= ~HEAP_PREV_BLOCK_USED;
next_block->prev_size = block_size;
/* Statistics */
++stats->free_blocks;
if ( stats->max_free_blocks < stats->free_blocks ) {
stats->max_free_blocks = stats->free_blocks;
}
}
/* Statistics */
--stats->used_blocks;
++stats->frees;
stats->free_size += block_size;
return( true );
}
bool _Heap_Free( Heap_Control *heap, void *alloc_begin_ptr )
{
Heap_Statistics *const stats = &heap->stats;
uintptr_t alloc_begin;
Heap_Block *block;
Heap_Block *next_block = NULL;
uintptr_t block_size = 0;
uintptr_t next_block_size = 0;
bool next_is_free = false;
/*
* If NULL return true so a free on NULL is considered a valid release. This
* is a special case that could be handled by the in heap check how-ever that
* would result in false being returned which is wrong.
*/
if ( alloc_begin_ptr == NULL ) {
return true;
}
alloc_begin = (uintptr_t) alloc_begin_ptr;
block = _Heap_Block_of_alloc_area( alloc_begin, heap->page_size );
if ( !_Heap_Is_block_in_heap( heap, block ) ) {
return false;
}
_Heap_Protection_block_check( heap, block );
block_size = _Heap_Block_size( block );
next_block = _Heap_Block_at( block, block_size );
if ( !_Heap_Is_block_in_heap( heap, next_block ) ) {
return false;
}
_Heap_Protection_block_check( heap, next_block );
if ( !_Heap_Is_prev_used( next_block ) ) {
_Heap_Protection_block_error( heap, block );
return false;
}
if ( !_Heap_Protection_determine_block_free( heap, block ) ) {
return true;
}
next_block_size = _Heap_Block_size( next_block );
next_is_free = next_block != heap->last_block
&& !_Heap_Is_prev_used( _Heap_Block_at( next_block, next_block_size ));
if ( !_Heap_Is_prev_used( block ) ) {
uintptr_t const prev_size = block->prev_size;
Heap_Block * const prev_block = _Heap_Block_at( block, -prev_size );
if ( !_Heap_Is_block_in_heap( heap, prev_block ) ) {
_HAssert( false );
return( false );
}
/* As we always coalesce free blocks, the block that preceedes prev_block
must have been used. */
if ( !_Heap_Is_prev_used ( prev_block) ) {
_HAssert( false );
return( false );
}
if ( next_is_free ) { /* coalesce both */
uintptr_t const size = block_size + prev_size + next_block_size;
_Heap_Free_list_remove( next_block );
stats->free_blocks -= 1;
prev_block->size_and_flag = size | HEAP_PREV_BLOCK_USED;
next_block = _Heap_Block_at( prev_block, size );
_HAssert(!_Heap_Is_prev_used( next_block));
next_block->prev_size = size;
} else { /* coalesce prev */
uintptr_t const size = block_size + prev_size;
prev_block->size_and_flag = size | HEAP_PREV_BLOCK_USED;
next_block->size_and_flag &= ~HEAP_PREV_BLOCK_USED;
next_block->prev_size = size;
}
} else if ( next_is_free ) { /* coalesce next */
uintptr_t const size = block_size + next_block_size;
_Heap_Free_list_replace( next_block, block );
block->size_and_flag = size | HEAP_PREV_BLOCK_USED;
next_block = _Heap_Block_at( block, size );
next_block->prev_size = size;
} else { /* no coalesce */
/* Add 'block' to the head of the free blocks list as it tends to
produce less fragmentation than adding to the tail. */
_Heap_Free_list_insert_after( _Heap_Free_list_head( heap), block );
block->size_and_flag = block_size | HEAP_PREV_BLOCK_USED;
next_block->size_and_flag &= ~HEAP_PREV_BLOCK_USED;
next_block->prev_size = block_size;
/* Statistics */
++stats->free_blocks;
if ( stats->max_free_blocks < stats->free_blocks ) {
stats->max_free_blocks = stats->free_blocks;
}
}
/* Statistics */
--stats->used_blocks;
++stats->frees;
stats->free_size += block_size;
return( true );
}
void _Heap_Block_split(
Heap_Control *heap,
Heap_Block *block,
Heap_Block *free_list_anchor,
uintptr_t alloc_size
)
{
Heap_Statistics *const stats = &heap->stats;
uintptr_t const page_size = heap->page_size;
uintptr_t const min_block_size = heap->min_block_size;
uintptr_t const min_alloc_size = min_block_size - HEAP_BLOCK_HEADER_SIZE;
uintptr_t const block_size = _Heap_Block_size( block );
uintptr_t const used_size =
_Heap_Max( alloc_size, min_alloc_size ) + HEAP_BLOCK_HEADER_SIZE;
uintptr_t const used_block_size = _Heap_Align_up( used_size, page_size );
uintptr_t const free_size = block_size + HEAP_BLOCK_SIZE_OFFSET - used_size;
uintptr_t const free_size_limit = min_block_size + HEAP_BLOCK_SIZE_OFFSET;
Heap_Block *next_block = _Heap_Block_at( block, block_size );
_HAssert( used_size <= block_size + HEAP_BLOCK_SIZE_OFFSET );
_HAssert( used_size + free_size == block_size + HEAP_BLOCK_SIZE_OFFSET );
if ( free_size >= free_size_limit ) {
Heap_Block *const free_block = _Heap_Block_at( block, used_block_size );
uintptr_t free_block_size = block_size - used_block_size;
_HAssert( used_block_size + free_block_size == block_size );
_Heap_Block_set_size( block, used_block_size );
/* Statistics */
stats->free_size += free_block_size;
if ( _Heap_Is_used( next_block ) ) {
_Heap_Free_list_insert_after( free_list_anchor, free_block );
/* Statistics */
++stats->free_blocks;
} else {
uintptr_t const next_block_size = _Heap_Block_size( next_block );
_Heap_Free_list_replace( next_block, free_block );
free_block_size += next_block_size;
next_block = _Heap_Block_at( free_block, free_block_size );
}
free_block->size_and_flag = free_block_size | HEAP_PREV_BLOCK_USED;
next_block->prev_size = free_block_size;
next_block->size_and_flag &= ~HEAP_PREV_BLOCK_USED;
} else {
next_block->size_and_flag |= HEAP_PREV_BLOCK_USED;
}
}
