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      1 /*
      2  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #ifndef WEBRTC_SYSTEM_WRAPPERS_INTERFACE_ALIGNED_MALLOC_H_
     12 #define WEBRTC_SYSTEM_WRAPPERS_INTERFACE_ALIGNED_MALLOC_H_
     13 
     14 // The functions declared here
     15 // 1) Allocates block of aligned memory.
     16 // 2) Re-calculates a pointer such that it is aligned to a higher or equal
     17 //    address.
     18 // Note: alignment must be a power of two. The alignment is in bytes.
     19 
     20 #include <stddef.h>
     21 
     22 namespace webrtc {
     23 
     24 // Returns a pointer to the first boundry of |alignment| bytes following the
     25 // address of |ptr|.
     26 // Note that there is no guarantee that the memory in question is available.
     27 // |ptr| has no requirements other than it can't be NULL.
     28 void* GetRightAlign(const void* ptr, size_t alignment);
     29 
     30 // Allocates memory of |size| bytes aligned on an |alignment| boundry.
     31 // The return value is a pointer to the memory. Note that the memory must
     32 // be de-allocated using AlignedFree.
     33 void* AlignedMalloc(size_t size, size_t alignment);
     34 // De-allocates memory created using the AlignedMalloc() API.
     35 void AlignedFree(void* mem_block);
     36 
     37 // Templated versions to facilitate usage of aligned malloc without casting
     38 // to and from void*.
     39 template<typename T>
     40 T* GetRightAlign(const T* ptr, size_t alignment) {
     41   return reinterpret_cast<T*>(GetRightAlign(reinterpret_cast<const void*>(ptr),
     42                                             alignment));
     43 }
     44 template<typename T>
     45 T* AlignedMalloc(size_t size, size_t alignment) {
     46   return reinterpret_cast<T*>(AlignedMalloc(size, alignment));
     47 }
     48 
     49 // Deleter for use with scoped_ptr. E.g., use as
     50 //   scoped_ptr<Foo, AlignedFreeDeleter> foo;
     51 struct AlignedFreeDeleter {
     52   inline void operator()(void* ptr) const {
     53     AlignedFree(ptr);
     54   }
     55 };
     56 
     57 }  // namespace webrtc
     58 
     59 #endif // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_ALIGNED_MALLOC_H_
     60