add BAlloc to simplify allocating arrays

misc/balloc.h

@@ -0,0 +1,121 @@
+/**
+ * @file balloc.h
+ * @author Ambroz Bizjak <ambrop7@gmail.com>
+ * 
+ * @section LICENSE
+ * 
+ * This file is part of BadVPN.
+ * 
+ * BadVPN is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ * 
+ * BadVPN is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ * 
+ * @section DESCRIPTION
+ * 
+ * Memory allocation functions.
+ */
+
+#ifndef BADVPN_MISC_BALLOC_H
+#define BADVPN_MISC_BALLOC_H
+
+#include <stddef.h>
+#include <inttypes.h>
+#include <stdlib.h>
+
+#include <misc/debug.h>
+
+/**
+ * Allocates memory.
+ * 
+ * @param bytes number of bytes to allocate. Must be >0.
+ * @return a non-NULL pointer to the memory, or NULL on failure.
+ *         The memory allocated can be freed using {@link BFree}.
+ */
+static void * BAlloc (size_t bytes);
+
+/**
+ * Frees memory.
+ * 
+ * @param m memory to free. Must have been obtained with {@link BAlloc},
+ *          {@link BAllocArray}, or {@link BAllocArray2}. May be NULL;
+ *          in this case, this function does nothing.
+ */
+static void BFree (void *m);
+
+/**
+ * Allocates memory for an array.
+ * A check is first done to make sure the multiplication doesn't overflow;
+ * otherwise, this is equivalent to {@link BAlloc}(count * bytes).
+ * 
+ * @param count number of elements. Must be >0.
+ * @param bytes size of one array element. Must be >0.
+ * @return a non-NULL pointer to the memory, or NULL on failure.
+ *         The memory allocated can be freed using {@link BFree}.
+ */
+static void * BAllocArray (size_t count, size_t bytes);
+
+/**
+ * Allocates memory for a two-dimensional array.
+ * 
+ * Checks are first done to make sure the multiplications don't overflow;
+ * otherwise, this is equivalent to {@link BAlloc}((count2 * (count1 * bytes)).
+ * 
+ * @param count2 number of elements in one dimension. Must be >0.
+ * @param count1 number of elements in the other dimension. Must be >0.
+ * @param bytes size of one array element. Must be >0.
+ * @return a non-NULL pointer to the memory, or NULL on failure.
+ *         The memory allocated can be freed using {@link BFree}.
+ */
+static void * BAllocArray2 (size_t count2, size_t count1, size_t bytes);
+
+void * BAlloc (size_t bytes)
+{
+    ASSERT(bytes > 0)
+    
+    return malloc(bytes);
+}
+
+void BFree (void *m)
+{
+    free(m);
+}
+
+void * BAllocArray (size_t count, size_t bytes)
+{
+    ASSERT(count > 0)
+    ASSERT(bytes > 0)
+    
+    if (count > SIZE_MAX / bytes) {
+        return NULL;
+    }
+    
+    return BAlloc(count * bytes);
+}
+
+void * BAllocArray2 (size_t count2, size_t count1, size_t bytes)
+{
+    ASSERT(count2 > 0)
+    ASSERT(count1 > 0)
+    ASSERT(bytes > 0)
+    
+    if (count1 > SIZE_MAX / bytes) {
+        return NULL;
+    }
+    
+    if (count2 > SIZE_MAX / (count1 * bytes)) {
+        return NULL;
+    }
+    
+    return BAlloc(count2 * (count1 * bytes));
+}
+
+#endif