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/*
* Copyright (c) 2004, Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the uIP TCP/IP stack
*
* Author: Adam Dunkels <adam@sics.se>
*
* $Id: memb.h,v 1.1 2006/06/12 08:21:43 adam Exp $
*/
/**
* \defgroup memb Memory block management functions
*
* The memory block allocation routines provide a simple yet powerful
* set of functions for managing a set of memory blocks of fixed
* size. A set of memory blocks is statically declared with the
* MEMB() macro. Memory blocks are allocated from the declared
* memory by the memb_alloc() function, and are deallocated with the
* memb_free() function.
*
* \note Because of namespace clashes only one MEMB() can be
* declared per C module, and the name scope of a MEMB() memory
* block is local to each C module.
*
* The following example shows how to declare and use a memory block
* called "cmem" which has 8 chunks of memory with each memory chunk
* being 20 bytes large.
*
* @{
*/
/**
* \file
* Memory block allocation routines.
* \author
* Adam Dunkels <adam@sics.se>
*
*/
#ifndef __MEMB_H__
#define __MEMB_H__
/*
* Here we define a C preprocessing macro for concatenating to
* strings. We need use two macros in order to allow concatenation of
* two #defined macros.
*/
#define MEMB_CONCAT2(s1, s2) s1##s2
#define MEMB_CONCAT(s1, s2) MEMB_CONCAT2(s1, s2)
/**
* Declare a memory block.
*
* This macro is used to staticall declare a block of memory that can
* be used by the block allocation functions. The macro statically
* declares a C array with a size that matches the specified number of
* blocks and their individual sizes.
*
* Example:
\code
MEMB(connections, sizeof(struct connection), 16);
\endcode
*
* \param name The name of the memory block (later used with
* memb_init(), memb_alloc() and memb_free()).
*
* \param size The size of each memory chunk, in bytes.
*
* \param num The total number of memory chunks in the block.
*
*/
#define MEMB(name, structure, num) \
static char MEMB_CONCAT(name,_memb_count)[num]; \
static structure MEMB_CONCAT(name,_memb_mem)[num]; \
static struct memb_blocks name = {sizeof(structure), num, \
MEMB_CONCAT(name,_memb_count), \
(void *)MEMB_CONCAT(name,_memb_mem)}
struct memb_blocks {
unsigned short size;
unsigned short num;
char *count;
void *mem;
};
/**
* Initialize a memory block that was declared with MEMB().
*
* \param m A memory block previosly declared with MEMB().
*/
void memb_init(struct memb_blocks *m);
/**
* Allocate a memory block from a block of memory declared with MEMB().
*
* \param m A memory block previosly declared with MEMB().
*/
void *memb_alloc(struct memb_blocks *m);
/**
* Deallocate a memory block from a memory block previously declared
* with MEMB().
*
* \param m m A memory block previosly declared with MEMB().
*
* \param ptr A pointer to the memory block that is to be deallocated.
*
* \return The new reference count for the memory block (should be 0
* if successfully deallocated) or -1 if the pointer "ptr" did not
* point to a legal memory block.
*/
char memb_free(struct memb_blocks *m, void *ptr);
/** @} */
#endif /* __MEMB_H__ */
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