klish/lub/heap/heap_merge_with_previous.c

#include "private.h"

/*--------------------------------------------------------- */
lub_heap_status_t
lub_heap_merge_with_previous(lub_heap_t * this, lub_heap_block_t * block)
{
	lub_heap_status_t result = LUB_HEAP_FAILED;
	lub_heap_block_t *prev_block;

	do {
		/* see whether there is a free block just before us */
		prev_block = lub_heap_block_getprevious(block);
		if ((NULL != prev_block)
		    && (1 == prev_block->free.tag.free)) {
			lub_heap_tag_t *tail;

			if (BOOL_FALSE == lub_heap_block_check(prev_block)) {
				result = LUB_HEAP_CORRUPTED;
				break;
			}
			tail = lub_heap_block__get_tail(block);

			if (1 == block->free.tag.free) {
				/* remove this free block from the tree */
				lub_bintree_remove(&this->free_tree, block);
				--this->stats.free_blocks;
				this->stats.free_bytes -=
				    (block->free.tag.words << 2);
				this->stats.free_bytes +=
				    sizeof(lub_heap_alloc_block_t);
				this->stats.free_overhead -=
				    sizeof(lub_heap_alloc_block_t);
			}
			/* now add this memory to the previous free block */
			lub_heap_graft_to_top(this,
					      prev_block,
					      block,
					      block->alloc.tag.words,
					      tail->segment,
					      block->free.tag.
					      free ? BOOL_TRUE : BOOL_FALSE);
			result = LUB_HEAP_OK;
		}
	} while (0);

	return result;
}

/*--------------------------------------------------------- */