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8df643b387
To add ref counting to any class while avoiding virtual functions for reference counting. This template can both slightly reduce binary size and slightly improve performance. Bug: webrtc:11308 Change-Id: I90ac735f6c220ee2a1a991a71039acdb0ca86453 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/198845 Commit-Queue: Danil Chapovalov <danilchap@webrtc.org> Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org> Reviewed-by: Niels Moller <nisse@webrtc.org> Cr-Commit-Position: refs/heads/master@{#33058}
125 lines
3.2 KiB
C++
125 lines
3.2 KiB
C++
/*
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* Copyright 2016 The WebRTC Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "rtc_base/copy_on_write_buffer.h"
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#include <stddef.h>
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namespace rtc {
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CopyOnWriteBuffer::CopyOnWriteBuffer() : offset_(0), size_(0) {
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RTC_DCHECK(IsConsistent());
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}
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CopyOnWriteBuffer::CopyOnWriteBuffer(const CopyOnWriteBuffer& buf)
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: buffer_(buf.buffer_), offset_(buf.offset_), size_(buf.size_) {}
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CopyOnWriteBuffer::CopyOnWriteBuffer(CopyOnWriteBuffer&& buf)
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: buffer_(std::move(buf.buffer_)), offset_(buf.offset_), size_(buf.size_) {
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buf.offset_ = 0;
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buf.size_ = 0;
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RTC_DCHECK(IsConsistent());
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}
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CopyOnWriteBuffer::CopyOnWriteBuffer(const std::string& s)
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: CopyOnWriteBuffer(s.data(), s.length()) {}
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CopyOnWriteBuffer::CopyOnWriteBuffer(size_t size)
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: buffer_(size > 0 ? new RefCountedBuffer(size) : nullptr),
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offset_(0),
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size_(size) {
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RTC_DCHECK(IsConsistent());
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}
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CopyOnWriteBuffer::CopyOnWriteBuffer(size_t size, size_t capacity)
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: buffer_(size > 0 || capacity > 0 ? new RefCountedBuffer(size, capacity)
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: nullptr),
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offset_(0),
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size_(size) {
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RTC_DCHECK(IsConsistent());
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}
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CopyOnWriteBuffer::~CopyOnWriteBuffer() = default;
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bool CopyOnWriteBuffer::operator==(const CopyOnWriteBuffer& buf) const {
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// Must either be the same view of the same buffer or have the same contents.
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RTC_DCHECK(IsConsistent());
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RTC_DCHECK(buf.IsConsistent());
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return size_ == buf.size_ &&
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(cdata() == buf.cdata() || memcmp(cdata(), buf.cdata(), size_) == 0);
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}
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void CopyOnWriteBuffer::SetSize(size_t size) {
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RTC_DCHECK(IsConsistent());
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if (!buffer_) {
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if (size > 0) {
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buffer_ = new RefCountedBuffer(size);
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offset_ = 0;
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size_ = size;
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}
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RTC_DCHECK(IsConsistent());
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return;
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}
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if (size <= size_) {
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size_ = size;
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return;
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}
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UnshareAndEnsureCapacity(std::max(capacity(), size));
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buffer_->SetSize(size + offset_);
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size_ = size;
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RTC_DCHECK(IsConsistent());
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}
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void CopyOnWriteBuffer::EnsureCapacity(size_t new_capacity) {
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RTC_DCHECK(IsConsistent());
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if (!buffer_) {
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if (new_capacity > 0) {
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buffer_ = new RefCountedBuffer(0, new_capacity);
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offset_ = 0;
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size_ = 0;
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}
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RTC_DCHECK(IsConsistent());
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return;
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} else if (new_capacity <= capacity()) {
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return;
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}
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UnshareAndEnsureCapacity(new_capacity);
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RTC_DCHECK(IsConsistent());
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}
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void CopyOnWriteBuffer::Clear() {
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if (!buffer_)
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return;
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if (buffer_->HasOneRef()) {
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buffer_->Clear();
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} else {
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buffer_ = new RefCountedBuffer(0, capacity());
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}
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offset_ = 0;
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size_ = 0;
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RTC_DCHECK(IsConsistent());
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}
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void CopyOnWriteBuffer::UnshareAndEnsureCapacity(size_t new_capacity) {
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if (buffer_->HasOneRef() && new_capacity <= capacity()) {
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return;
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}
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buffer_ =
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new RefCountedBuffer(buffer_->data() + offset_, size_, new_capacity);
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offset_ = 0;
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RTC_DCHECK(IsConsistent());
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}
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} // namespace rtc
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