heap.c File Reference

Simple heap allocator. More...

Functions
void	heap_init (struct heap *heap, void *buf, size_t buflen, Morecore_func_t morecore_func)
	Initialise a new heap. More...
void *	heap_alloc (struct heap *heap, size_t nbytes)
	Equivalent of malloc; allocates memory out of given heap. More...
void	heap_free (struct heap *heap, void *ap)
	Equivalent of free: put block back in free list.
union heap_header *	heap_default_morecore (struct heap *heap, unsigned nu)
	sbrk() equivalent. More...

Detailed Description

Simple heap allocator.

This file implements a very simple heap allocator, based on K&R malloc.

Function Documentation

void* heap_alloc	(	struct heap *	heap,
		size_t	nbytes
	)

Equivalent of malloc; allocates memory out of given heap.

Returns

NULL on failure

union heap_header* heap_default_morecore	(	struct heap *	heap,
		unsigned	nu
	)

sbrk() equivalent.

This function allocates at least the amount given by 'nu' in sizeof(::Header) byte units. It returns a pointer to the freelist header of the memory region. NULL is returned when out of memory.

Parameters

nu	Number of memory units (1 unit == sizeof(::Header) bytes)

Returns

Pointer to freelist header of new memory region or NULL on out of memory.

void heap_init	(	struct heap *	heap,
		void *	buf,
		size_t	buflen,
		Morecore_func_t	morecore_func
	)

Initialise a new heap.

Parameters

heap	Heap structure to be filled in
buf	Memory buffer out of which to allocate
buflen	Size of buffer
morecore_func	Function to call to increase heap, or NULL