/*
 * partition_realloc.c
 */
#include <string.h>

#include "private.h"

/*--------------------------------------------------------- */
void
lub_partition_stop_here(lub_heap_status_t status,
			char *old_ptr, size_t new_size)
{
	/* This is provided as a debug aid */
	status = status;
	old_ptr = old_ptr;
	new_size = new_size;
}

/*--------------------------------------------------------- */
void lub_partition_time_to_die(lub_partition_t * this)
{
	bool_t time_to_die = BOOL_TRUE;
	lub_heap_stats_t stats;
	lub_heap_t *local_heap = lub_partition__get_local_heap(this);
	if (local_heap) {
		lub_heap__get_stats(local_heap, &stats);
		if (stats.alloc_blocks) {
			time_to_die = BOOL_FALSE;
		}
	}
	if (BOOL_FALSE == time_to_die) {
		lub_partition_lock(this);
		lub_heap__get_stats(this->m_global_heap, &stats);
		lub_partition_unlock(this);
		if (stats.alloc_blocks) {
			time_to_die = BOOL_FALSE;
		}
	}
	if (BOOL_TRUE == time_to_die) {
		/* and so the time has come... */
		lub_partition_destroy(this);
	}
}

/*--------------------------------------------------------- */
lub_heap_status_t
lub_partition_global_realloc(lub_partition_t * this,
			     char **ptr,
			     size_t size, lub_heap_align_t alignment)
{
	lub_heap_status_t status = LUB_HEAP_FAILED;
	lub_partition_lock(this);
	if (!this->m_global_heap) {
		/*
		 * Create the global heap
		 */
		size_t required = size;
		void *segment = lub_partition_segment_alloc(this, &required);
		this->m_global_heap = lub_heap_create(segment, required);
	}
	if (this->m_global_heap) {
		status =
		    lub_heap_realloc(this->m_global_heap, ptr, size, alignment);
		if (LUB_HEAP_FAILED == status) {
			/* expand memory and try again */
			if (lub_partition_extend_memory(this, size)) {
				status = lub_heap_realloc(this->m_global_heap,
							  ptr, size, alignment);
			}
		}
	}
	lub_partition_unlock(this);
	return status;
}

/*--------------------------------------------------------- */
lub_heap_status_t
lub_partition_realloc(lub_partition_t * this,
		      char **ptr, size_t size, lub_heap_align_t alignment)
{
	lub_heap_status_t status = LUB_HEAP_FAILED;
	size_t requested_size = size;
	lub_heap_t *local_heap;

	if ((0 == size) && (0 == *ptr)) {
		/* simple optimisation */
		return LUB_HEAP_OK;
	}
	if (this->m_dying) {
		local_heap = lub_partition__get_local_heap(this);
		if (size) {
			/* don't allocate any new memory when dying */
			size = 0;
		}
	} else {
		local_heap = lub_partition_findcreate_local_heap(this);
	}
	if (local_heap) {
		/* try the fast local heap first */
		status = lub_heap_realloc(local_heap, ptr, size, alignment);
	}
	if ((LUB_HEAP_FAILED == status) || (LUB_HEAP_INVALID_POINTER == status)) {
		char *old_ptr = 0;

		if (local_heap && (LUB_HEAP_FAILED == status) && size) {
			/* we need to reallocate from the global and copy from the local */
			old_ptr = *ptr;
			*ptr = 0;
		}
		/* time to use the slower global heap */
		status =
		    lub_partition_global_realloc(this, ptr, size, alignment);
		if (old_ptr && (LUB_HEAP_OK == status)) {
			/* copy from the local to the global */
			memcpy(*ptr, old_ptr, size);

			/* and release the local block */
			status =
			    lub_heap_realloc(local_heap, &old_ptr, 0,
					     alignment);
		}
	}
	if (LUB_HEAP_OK != status) {
		lub_partition_stop_here(status, *ptr, size);
	}
	/* allow the partion to destroy itself if necessary */
	if (this->m_dying) {
		lub_partition_time_to_die(this);
		if (requested_size) {
			/* we don't allocate memory whilst dying */
			status = LUB_HEAP_FAILED;
		}
	}
	return status;
}

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