Data Structures
struct	OPHeap
	Memory allocator object with persistent storage on disk. More...

Macros
#define	OPHEAP_BITS 36
	Size of OPHeap represented in bits.

#define	OPHEAP_SIZE (1UL << OPHEAP_BITS)
	Size of OPHeap.

#define	OPLENREF_MAX_LEN (1ULL << (64 - OPHEAP_BITS))
	Maximum size oplenref_t can hold. More...

Typedefs
typedef uintptr_t	opref_t
	The "pointer type" used within objects created by OPHeap. More...

typedef uintptr_t	oplenref_t
	Another "pointer type" used within objects created in OPHeap. More...

Functions
static opref_t	OPPtr2Ref (void *addr)
	Converts a pointer allocated in OPHeap to an opref_t. More...

static void *	OPRef2Ptr (void *ptr_in_heap, opref_t ref)
	Converts an opref_t reference to a regular pointer. More...

static size_t	OPLenRef2Size (oplenref_t ref)
	Obtain the size encoded in oplenref_t. More...

static void *	OPLenRef2Ptr (oplenref_t *ref, size_t container_size)
	Converts an oplenref_t reference to a regular pointer. More...

static void *	OPLenRef2PtrOnHeap (oplenref_t ref, size_t container_size, OPHeap heap)
	Converts an oplenref_t reference to a regular pointer on specified heap. More...

static void	OPLenRefCreate (oplenref_t ref, void data, size_t data_size, size_t container_size)
	A constructor for oplenref_t to hold the input data. More...

static void	OPLenRefDelete (oplenref_t *ref, size_t container_size)
	A destructor for oplenref_t. More...

static void	OPLenRefRelpace (oplenref_t ref, void data, size_t data_size, size_t container_size)
	Relace the data stored in oplenref_t. More...

Detailed Description

Macro Definition Documentation

◆ OPLENREF_MAX_LEN

#define OPLENREF_MAX_LEN (1ULL << (64 - OPHEAP_BITS))

#include <opic/op_malloc.h>

Maximum size oplenref_t can hold.

The size is roughly 256MB, which should be sufficient for most applications.

Definition at line 143 of file op_malloc.h.

Typedef Documentation

◆ opref_t

opref_t

#include <opic/op_malloc.h>

The "pointer type" used within objects created by OPHeap.

For all the objects relationship in OPHeap, user must use opref_t or oplenref_t instead of regular pointer. Regular pointers would be invalid when OPHeap is written to disk. To access the object referenced by opref_t, first dereference opref_t to regular pointer, then dereference the pointer.

Unfortunately, C type system is quite weak. It would be better if we have the following features:

preserve the type information of the address we points to.
operator overload, or makes every symbol posible to be used as an operator like what Haskell does. Common operation like dereferencing should have its own operator.

Here is an example of how to reference other objects using opref_t:

struct A {
  opref_t ref_b;
};
struct B {
  int x;
};
OPHeap* heap = OPHeapOpenTmp();
struct A* a = OPMalloc(heap, sizeof(struct A));
struct B* b = OPMalloc(heap, sizeof(struct B));
struct B* b2;
// We store the pointer as opref_t
a->ref_b = OPPtr2Ref(b);
// When accessing the memory, dereference it as a pointer
b2 = OPRef2Ptr(a, a->ref_b);

See also

Definition at line 109 of file op_malloc.h.

◆ oplenref_t

oplenref_t

#include <opic/op_malloc.h>

Another "pointer type" used within objects created in OPHeap.

oplenref_t can encode an object created in OPHeap and the size of such object. User can query the size of the object by OPLenRef2Szie. The size of the object must smaller than OPLENREF_MAX_LEN, which is 256MB and suppose to be sufficient for regular use.

When oplenref_t is used in a container, oplenref_t can be used to encode the inline data in the container. The container holding oplenref_t can provide additional space next to oplenref_t to hold the inline data. When encoding or decoding oplenref_t the addtional space information must present so we know if the data is next to oplenref_t, or it is somewhere else in OPHeap.

See also

Definition at line 135 of file op_malloc.h.

Function Documentation

◆ OPPtr2Ref()

static opref_t OPPtr2Ref ( void * addr )

inlinestatic

#include <opic/op_malloc.h>

Converts a pointer allocated in OPHeap to an opref_t.

Parameters

addr	Any pointer that is allocated with OPHeap.

Returns: An opref_t value.

Definition at line 326 of file op_malloc.h.

◆ OPRef2Ptr()

static void* OPRef2Ptr	(	void *	ptr_in_heap,
		opref_t	ref
	)

inlinestatic

#include <opic/op_malloc.h>

Converts an opref_t reference to a regular pointer.

Parameters

ptr_in_heap	Any pointer in the heap, including OPHeap*.
ref	A opref_t value.

Returns: A regular pointer.

Definition at line 340 of file op_malloc.h.

◆ OPLenRef2Size()

static size_t OPLenRef2Size ( oplenref_t ref )

inlinestatic

#include <opic/op_malloc.h>

Obtain the size encoded in oplenref_t.

Parameters

ref	A oplenref_t value.

Returns: The size of the object it pointed to.

Definition at line 353 of file op_malloc.h.

◆ OPLenRef2Ptr()

static void* OPLenRef2Ptr	(	oplenref_t *	ref,
		size_t	container_size
	)

inlinestatic

#include <opic/op_malloc.h>

Converts an oplenref_t reference to a regular pointer.

Parameters

ref	Pointer to oplenref_t.
container_size	Size of the container that holds oplenref_t. If used without a container, set this parameter to 0.

Returns: A regular pointer.

Definition at line 405 of file op_malloc.h.

◆ OPLenRef2PtrOnHeap()

static void* OPLenRef2PtrOnHeap	(	oplenref_t *	ref,
		size_t	container_size,
		OPHeap *	heap
	)

inlinestatic

#include <opic/op_malloc.h>

Converts an oplenref_t reference to a regular pointer on specified heap.

This method is useful when oplenref_t is not on OPHeap, therefore we need to assist with a specific heap.

Parameters

ref	Pointer to oplenref_t.
container_size	Size of the container that holds oplenref_t. If used without a container, set this parameter to 0.
heap	Address to OPHeap where the data pointer may locate at.

Returns: A regular pointer.

Definition at line 430 of file op_malloc.h.

◆ OPLenRefCreate()

static void OPLenRefCreate	(	oplenref_t *	ref,
		void *	data,
		size_t	data_size,
		size_t	container_size
	)

inlinestatic

#include <opic/op_malloc.h>

A constructor for oplenref_t to hold the input data.

When oplenref_t used in a container, there would be some spaces next to the oplenref_t address that can hold inline data. The inline space is specified by the container_size. Data get copied to the inline space if the data_size is smaller than the container_size; otherwise the data would get copied to a newly allocated object in OPHeap. In either case, oplenref_t would store the information of which scheme was used.

Parameters

ref	Pointer to oplenref_t.
data	The data to copy over to OPHeap.
data_size	Size of the data. This size must smaller than OPLENREF_MAX_LEN.
container_size	Size of the container that holds oplenref_t. If used without a container, set this paramter to 0.

Definition at line 461 of file op_malloc.h.

◆ OPLenRefDelete()

static void OPLenRefDelete	(	oplenref_t *	ref,
		size_t	container_size
	)

inlinestatic

#include <opic/op_malloc.h>

A destructor for oplenref_t.

Deallocates the data stored in oplenref_t.

Parameters

ref	Pointer to oplenref_t.
container_size	Size of the container that holds oplenref_t. If used without a container, set this paramter to 0.

Definition at line 502 of file op_malloc.h.

◆ OPLenRefRelpace()

static void OPLenRefRelpace	(	oplenref_t *	ref,
		void *	data,
		size_t	data_size,
		size_t	container_size
	)

inlinestatic

#include <opic/op_malloc.h>

Relace the data stored in oplenref_t.

Will deallocate the original data stored in oplenref_t if it exists.

Parameters

ref	Pointer to oplenref_t.
data	The data to copy over to OPHeap.
data_size	Size of the data.
container_size	Size of the container that holds oplenref_t. If used without a container, set this paramter to 0.

Definition at line 527 of file op_malloc.h.

Data Structures

Macros

Typedefs

Functions

Detailed Description

Macro Definition Documentation

◆ OPLENREF_MAX_LEN

Typedef Documentation

◆ opref_t

◆ oplenref_t

Function Documentation

◆ OPPtr2Ref()

◆ OPRef2Ptr()

◆ OPLenRef2Size()

◆ OPLenRef2Ptr()

◆ OPLenRef2PtrOnHeap()

◆ OPLenRefCreate()

◆ OPLenRefDelete()

◆ OPLenRefRelpace()