arena.c File Reference

Source for Arena Library (CBL) More...

#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include "cbl/assert.h"
#include "cbl/except.h"
#include "arena.h"

Include dependency graph for arena.c:

Functions
arena_t *()	arena_new (void)
	creates a new arena.
void()	arena_dispose (arena_t **parena)
	disposes an arena.
void *()	arena_alloc (arena_t *arena, size_t n, const char *file, int line)
	allocates storage associated with an arena.
void *()	arena_calloc (arena_t *arena, size_t c, size_t n, const char *file, int line)
	allocates zero-filled storage associated with an arena.
void()	arena_free (arena_t *arena)
	deallocates all storages belonging to an arena.
Variables
const except_t	arena_exceptfailNew = { "Arena creation failed" }
	exception for arena creation failure.
const except_t	arena_exceptfailAlloc = { "Arena allocation failed" }
	exception for arena memory allocation failure.

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Detailed Description

Source for Arena Library (CBL)

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Function Documentation

void*() arena_alloc	(	arena_t *	arena,
		size_t	n,
		const char *	file,
		int	line
	)

allocates storage associated with an arena.

arena_alloc() allocates storage for an arena as malloc() or mem_alloc() does.

Possible exceptions: assert_exceptfail, arena_exceptfailAlloc

Unchecked errors: foreign data structure given for arena

Parameters:

[in,out]	arena	arena for which storage to be allocated
[in]	n	size of storage requested in bytes
[in]	file	file name in which storage requested
[in]	func	function name in which storage requested (if C99 supported)
[in]	line	line number on which storage requested

Returns:

storage allocated for given arena

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void*() arena_calloc	(	arena_t *	arena,
		size_t	c,
		size_t	n,
		const char *	file,
		int	line
	)

allocates zero-filled storage associated with an arena.

arena_calloc() does the same as arena_alloc() except that it returns zero-filled storage.

Possible exceptions: assert_exceptfail, arena_exceptfailAlloc

Unchecked errors: foreign data structure given for arena

Parameters:

[in,out]	arena	arena for which zero-filled storage is to be allocated
[in]	c	number of items to be allocated
[in]	n	size in bytes for one item
[in]	file	file name in which storage requested
[in]	func	function name in which storage requested (if C99 supported)
[in]	line	line number on which storage requested

Returns:

zero-filled storage allocated for arena

Todo:

Some improvements are possible and planned:

• the C standard requires calloc() return a null pointer if it cannot allocates storage of the size c * n in bytes, which allows no overflow in computing the multiplication. Overflow checking is necessary to mimic the behavior of calloc().

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void() arena_dispose

(

arena_t **

parena

)

disposes an arena.

arena_dispose() releases storages belonging to a given arena and disposes it. Do not confuse with arena_free() which gets all storages of an arena deallocated but does not destroy the arena itself.

Note that storages belonging to freelist is not deallcated by arena_dispose() because it is possibly used by other arenas. Thus, a tool detecting the memory leakage problem might say there is leakage caused by the library, but that is intended not a bug.

Possible exceptions: assert_exceptfail

Unchecked errors: foreign data structure given for parena

Parameters:

[in,out]

parena

pointer to arena to dispose

Returns:

nothing

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void() arena_free

(

arena_t *

arena

)

deallocates all storages belonging to an arena.

arena_free() releases all storages belonging to a given arena.

Possible exceptions: assert_exceptfail

Unchecked errors: foreign data structure given for arena

Parameters:

[in,out]

arena

arena whose storages to be deallocated

Returns:

nothing

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arena_t*() arena_new

(

void

)

creates a new arena.

arena_new() creates a new arena and initialize it to indicate an empty arena.

Possible exceptions: arena_exceptfailNew

Unchecked errors: none

Returns:

new arena created