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https://github.com/claunia/findcrcs.git
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67 lines
2.2 KiB
C++
67 lines
2.2 KiB
C++
// Copyright 2010 Google Inc. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// Poor man's platform-independent implementation of aligned memory allocator.
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#ifndef CRCUTIL_ALIGNED_ALLOC_H_
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#define CRCUTIL_ALIGNED_ALLOC_H_
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#include "std_headers.h" // size_t, ptrdiff_t
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namespace crcutil {
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// Allocates a block of memory of "size" bytes so that a field
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// at "field_offset" is aligned on "align" boundary.
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//
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// NB #1: "align" shall be exact power of two.
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//
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// NB #2: memory allocated by AlignedAlloc should be release by AlignedFree().
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//
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inline void *AlignedAlloc(size_t size,
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size_t field_offset,
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size_t align,
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const void **allocated_mem) {
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if (align == 0 || (align & (align - 1)) != 0 || align < sizeof(char *)) {
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align = sizeof(*allocated_mem);
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}
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size += align - 1 + sizeof(*allocated_mem);
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char *allocated_memory = new char[size];
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char *aligned_memory = allocated_memory + sizeof(*allocated_mem);
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field_offset &= align - 1;
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size_t actual_alignment =
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reinterpret_cast<size_t>(aligned_memory + field_offset) & (align - 1);
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if (actual_alignment != 0) {
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aligned_memory += align - actual_alignment;
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}
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reinterpret_cast<char **>(aligned_memory)[-1] = allocated_memory;
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if (allocated_mem != NULL) {
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*allocated_mem = allocated_memory;
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}
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return aligned_memory;
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}
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// Frees memory allocated by AlignedAlloc().
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inline void AlignedFree(void *aligned_memory) {
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if (aligned_memory != NULL) {
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char *allocated_memory = reinterpret_cast<char **>(aligned_memory)[-1];
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delete[] allocated_memory;
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}
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}
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} // namespace crcutil
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#endif // CRCUTIL_ALIGNED_ALLOC_H_
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