GNU libmicrohttpd  0.9.72
memorypool.c File Reference

memory pool More...

#include "memorypool.h"
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include "mhd_assert.h"
Include dependency graph for memorypool.c:

Go to the source code of this file.

Macros

#define MAP_FAILED   ((void*) -1)
 
#define ALIGN_SIZE   (2 * sizeof(void*))
 
#define ROUND_TO_ALIGN(n)
 
#define MHD_DEF_PAGE_SIZE_   (4096)
 

Functions

void MHD_init_mem_pools_ (void)
 
struct MemoryPool * MHD_pool_create (size_t max)
 
void MHD_pool_destroy (struct MemoryPool *pool)
 
size_t MHD_pool_get_free (struct MemoryPool *pool)
 
void * MHD_pool_allocate (struct MemoryPool *pool, size_t size, bool from_end)
 
void * MHD_pool_reallocate (struct MemoryPool *pool, void *old, size_t old_size, size_t new_size)
 
void * MHD_pool_reset (struct MemoryPool *pool, void *keep, size_t copy_bytes, size_t new_size)
 

Variables

static size_t MHD_sys_page_size_ = MHD_DEF_PAGE_SIZE_
 

Detailed Description

memory pool

Author
Christian Grothoff
Karlson2k (Evgeny Grin)

Definition in file memorypool.c.

Macro Definition Documentation

◆ ALIGN_SIZE

#define ALIGN_SIZE   (2 * sizeof(void*))

Align to 2x word size (as GNU libc does).

Definition at line 60 of file memorypool.c.

◆ MAP_FAILED

#define MAP_FAILED   ((void*) -1)

Definition at line 54 of file memorypool.c.

◆ MHD_DEF_PAGE_SIZE_

#define MHD_DEF_PAGE_SIZE_   (4096)

Definition at line 73 of file memorypool.c.

◆ ROUND_TO_ALIGN

#define ROUND_TO_ALIGN (   n)
Value:
(((n) + (ALIGN_SIZE - 1)) \
#define ALIGN_SIZE
Definition: memorypool.c:60

Round up 'n' to a multiple of ALIGN_SIZE.

Definition at line 65 of file memorypool.c.

Function Documentation

◆ MHD_init_mem_pools_()

void MHD_init_mem_pools_ ( void  )

Initialise values for memory pools

Definition at line 85 of file memorypool.c.

References ALIGN_SIZE, mhd_assert, MHD_DEF_PAGE_SIZE_, and MHD_sys_page_size_.

Referenced by MHD_init().

Here is the caller graph for this function:

◆ MHD_pool_allocate()

void* MHD_pool_allocate ( struct MemoryPool *  pool,
size_t  size,
bool  from_end 
)

Allocate size bytes from the pool.

Parameters
poolmemory pool to use for the operation
sizenumber of bytes to allocate
from_endallocate from end of pool (set to 'true'); use this for small, persistent allocations that will never be reallocated
Returns
NULL if the pool cannot support size more bytes

Definition at line 265 of file memorypool.c.

References mhd_assert, NULL, and ROUND_TO_ALIGN.

◆ MHD_pool_create()

struct MemoryPool* MHD_pool_create ( size_t  max)

Create a memory pool.

Parameters
maxmaximum size of the pool
Returns
NULL on error

Definition at line 146 of file memorypool.c.

References ALIGN_SIZE, MAP_FAILED, mhd_assert, MHD_sys_page_size_, NULL, and ROUND_TO_ALIGN.

◆ MHD_pool_destroy()

void MHD_pool_destroy ( struct MemoryPool *  pool)

Destroy a memory pool.

Parameters
poolmemory pool to destroy

Definition at line 214 of file memorypool.c.

References mhd_assert, and NULL.

◆ MHD_pool_get_free()

size_t MHD_pool_get_free ( struct MemoryPool *  pool)

Check how much memory is left in the pool

Parameters
poolpool to check
Returns
number of bytes still available in pool

Definition at line 245 of file memorypool.c.

References mhd_assert.

◆ MHD_pool_reallocate()

void* MHD_pool_reallocate ( struct MemoryPool *  pool,
void *  old,
size_t  old_size,
size_t  new_size 
)

Reallocate a block of memory obtained from the pool. This is particularly efficient when growing or shrinking the block that was last (re)allocated. If the given block is not the most recently (re)allocated block, the memory of the previous allocation may be leaked until the pool is destroyed or reset.

Parameters
poolmemory pool to use for the operation
oldthe existing block
old_sizethe size of the existing block
new_sizethe new size of the block
Returns
new address of the block, or NULL if the pool cannot support new_size bytes (old continues to be valid for old_size)

Definition at line 312 of file memorypool.c.

References mhd_assert, NULL, and ROUND_TO_ALIGN.

◆ MHD_pool_reset()

void* MHD_pool_reset ( struct MemoryPool *  pool,
void *  keep,
size_t  copy_bytes,
size_t  new_size 
)

Clear all entries from the memory pool except for keep of the given size. The pointer returned should be a buffer of new_size where the first copy_bytes are from keep.

Parameters
poolmemory pool to use for the operation
keeppointer to the entry to keep (maybe NULL)
copy_byteshow many bytes need to be kept at this address
new_sizehow many bytes should the allocation we return have? (should be larger or equal to copy_bytes)
Returns
addr new address of keep (if it had to change)

Size of area to zero-out

Definition at line 390 of file memorypool.c.

References mhd_assert, MHD_sys_page_size_, NULL, and ROUND_TO_ALIGN.

Variable Documentation

◆ MHD_sys_page_size_

size_t MHD_sys_page_size_ = MHD_DEF_PAGE_SIZE_
static

Size of memory page

Definition at line 79 of file memorypool.c.

Referenced by MHD_init_mem_pools_(), MHD_pool_create(), and MHD_pool_reset().