1 files changed, 98 insertions, 0 deletions
diff --git a/src/util/os_memory_aligned.h b/src/util/os_memory_aligned.h
new file mode 100644
index 00000000000..df398a32bfd
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+++ b/src/util/os_memory_aligned.h
@@ -0,0 +1,98 @@
+/**************************************************************************
+ * 
+ * Copyright 2008-2010 VMware, Inc.
+ * All Rights Reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ * 
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ * 
+ **************************************************************************/
+
+
+/*
+ * Memory alignment wrappers.
+ */
+
+
+#ifndef _OS_MEMORY_H_
+#error "Must not be included directly. Include os_memory.h instead"
+#endif
+
+
+#include "pipe/p_compiler.h"
+
+
+
+/**
+ * Add two size_t values with integer overflow check.
+ * TODO: leverage __builtin_add_overflow where available
+ */
+static inline bool
+add_overflow_size_t(size_t a, size_t b, size_t *res)
+{
+   *res = a + b;
+   return *res < a || *res < b;
+}
+
+
+/**
+ * Return memory on given byte alignment
+ */
+static inline void *
+os_malloc_aligned(size_t size, size_t alignment)
+{
+   char *ptr, *buf;
+   size_t alloc_size;
+
+   /*
+    * Calculate
+    *
+    *   alloc_size = size + alignment + sizeof(void *)
+    *
+    * while checking for overflow.
+    */
+   if (add_overflow_size_t(size, alignment, &alloc_size) ||
+       add_overflow_size_t(alloc_size, sizeof(void *), &alloc_size)) {
+      return NULL;
+   }
+
+   ptr = (char *) os_malloc(alloc_size);
+   if (!ptr)
+      return NULL;
+
+   buf = (char *)(((uintptr_t)ptr + sizeof(void *) + alignment - 1) & ~((uintptr_t)(alignment - 1)));
+   *(char **)(buf - sizeof(void *)) = ptr;
+
+   return buf;
+}
+
+
+/**
+ * Free memory returned by os_malloc_aligned().
+ */
+static inline void
+os_free_aligned(void *ptr)
+{
+   if (ptr) {
+      void **cubbyHole = (void **) ((char *) ptr - sizeof(void *));
+      void *realAddr = *cubbyHole;
+      os_free(realAddr);
+   }
+}