89 lines
2.3 KiB
C++
89 lines
2.3 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_MEMORY_ALIGNED_MEMORY_H_
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#define BASE_MEMORY_ALIGNED_MEMORY_H_
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#include <stddef.h>
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#include <stdint.h>
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#include <type_traits>
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#include "base/base_export.h"
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#include "base/compiler_specific.h"
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#include "base/logging.h"
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#include "base/process/process_metrics.h"
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#include "build/build_config.h"
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#if defined(COMPILER_MSVC)
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#include <malloc.h>
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#else
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#include <stdlib.h>
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#endif
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// A runtime sized aligned allocation can be created:
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//
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// float* my_array = static_cast<float*>(AlignedAlloc(size, alignment));
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//
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// // ... later, to release the memory:
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// AlignedFree(my_array);
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//
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// Or using unique_ptr:
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//
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// std::unique_ptr<float, AlignedFreeDeleter> my_array(
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// static_cast<float*>(AlignedAlloc(size, alignment)));
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namespace base {
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// This can be replaced with std::aligned_alloc when we have C++17.
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// Caveat: std::aligned_alloc requires the size parameter be an integral
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// multiple of alignment.
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BASE_EXPORT void* AlignedAlloc(size_t size, size_t alignment);
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inline void AlignedFree(void* ptr) {
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#if defined(COMPILER_MSVC)
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_aligned_free(ptr);
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#else
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free(ptr);
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#endif
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}
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// Deleter for use with unique_ptr. E.g., use as
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// std::unique_ptr<Foo, base::AlignedFreeDeleter> foo;
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struct AlignedFreeDeleter {
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inline void operator()(void* ptr) const {
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AlignedFree(ptr);
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}
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};
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#ifndef __has_builtin
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#define __has_builtin(x) 0 // Compatibility with non-clang compilers.
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#endif
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inline bool IsAligned(uintptr_t val, size_t alignment) {
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// If the compiler supports builtin alignment checks prefer them.
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#if __has_builtin(__builtin_is_aligned)
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return __builtin_is_aligned(val, alignment);
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#else
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DCHECK(!((alignment - 1) & alignment))
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<< alignment << " is not a power of two";
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return (val & (alignment - 1)) == 0;
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#endif
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}
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inline bool IsAligned(void* val, size_t alignment) {
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return IsAligned(reinterpret_cast<uintptr_t>(val), alignment);
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}
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template <typename Type>
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inline bool IsPageAligned(Type val) {
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static_assert(std::is_integral<Type>::value || std::is_pointer<Type>::value,
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"Integral or pointer type required");
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return base::IsAligned(val, base::GetPageSize());
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}
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} // namespace base
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#endif // BASE_MEMORY_ALIGNED_MEMORY_H_
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