Diff: lib/memb.c

Revision:

0:685224d2f66d

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/memb.c	Sat Jun 14 16:02:21 2014 +0000
@@ -0,0 +1,104 @@
+/*
+ * 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.c,v 1.1 2006/06/12 08:21:43 adam Exp $
+ */
+
+/**
+ * \addtogroup memb
+ * @{
+ */
+
+ /**
+ * \file
+ * Memory block allocation routines.
+ * \author Adam Dunkels <adam@sics.se>
+ */
+#include <string.h>
+
+#include "memb.h"
+
+/*---------------------------------------------------------------------------*/
+void
+memb_init(struct memb_blocks *m)
+{
+  memset(m->count, 0, m->num);
+  memset(m->mem, 0, m->size * m->num);
+}
+/*---------------------------------------------------------------------------*/
+void *
+memb_alloc(struct memb_blocks *m)
+{
+  int i;
+
+  for(i = 0; i < m->num; ++i) {
+    if(m->count[i] == 0) {
+      /* If this block was unused, we increase the reference count to
+	 indicate that it now is used and return a pointer to the
+	 memory block. */
+      ++(m->count[i]);
+      return (void *)((char *)m->mem + (i * m->size));
+    }
+  }
+
+  /* No free block was found, so we return NULL to indicate failure to
+     allocate block. */
+  return NULL;
+}
+/*---------------------------------------------------------------------------*/
+char
+memb_free(struct memb_blocks *m, void *ptr)
+{
+  int i;
+  char *ptr2;
+
+  /* Walk through the list of blocks and try to find the block to
+     which the pointer "ptr" points to. */
+  ptr2 = (char *)m->mem;
+  for(i = 0; i < m->num; ++i) {
+    
+    if(ptr2 == (char *)ptr) {
+      /* We've found to block to which "ptr" points so we decrease the
+	 reference count and return the new value of it. */
+      if(m->count[i] > 0) {
+	/* Make sure that we don't deallocate free memory. */
+	--(m->count[i]);
+      }
+      return m->count[i];
+    }
+    ptr2 += m->size;
+  }
+  return -1;
+}
+/*---------------------------------------------------------------------------*/
+
+/** @} */