Diff: lib/memb.h

Revision:

0:685224d2f66d

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+++ b/lib/memb.h	Sat Jun 14 16:02:21 2014 +0000
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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__ */