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/*
* Copyright 2019 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "rtc_base/memory/fifo_buffer.h"
#include <algorithm>
#include "rtc_base/thread.h"
namespace rtc {
FifoBuffer::FifoBuffer(size_t size)
: state_(SS_OPEN),
buffer_(new char[size]),
buffer_length_(size),
data_length_(0),
read_position_(0),
owner_(Thread::Current()) {
// all events are done on the owner_ thread
}
FifoBuffer::FifoBuffer(size_t size, Thread* owner)
: state_(SS_OPEN),
buffer_(new char[size]),
buffer_length_(size),
data_length_(0),
read_position_(0),
owner_(owner) {
// all events are done on the owner_ thread
}
FifoBuffer::~FifoBuffer() {}
bool FifoBuffer::GetBuffered(size_t* size) const {
webrtc::MutexLock lock(&mutex_);
*size = data_length_;
return true;
}
StreamState FifoBuffer::GetState() const {
webrtc::MutexLock lock(&mutex_);
return state_;
}
StreamResult FifoBuffer::Read(rtc::ArrayView<uint8_t> buffer,
size_t& bytes_read,
int& error) {
webrtc::MutexLock lock(&mutex_);
const bool was_writable = data_length_ < buffer_length_;
size_t copy = 0;
StreamResult result = ReadLocked(buffer.data(), buffer.size(), ©);
if (result == SR_SUCCESS) {
// If read was successful then adjust the read position and number of
// bytes buffered.
read_position_ = (read_position_ + copy) % buffer_length_;
data_length_ -= copy;
bytes_read = copy;
// if we were full before, and now we're not, post an event
if (!was_writable && copy > 0) {
PostEvent(SE_WRITE, 0);
}
}
return result;
}
StreamResult FifoBuffer::Write(rtc::ArrayView<const uint8_t> buffer,
size_t& bytes_written,
int& error) {
webrtc::MutexLock lock(&mutex_);
const bool was_readable = (data_length_ > 0);
size_t copy = 0;
StreamResult result = WriteLocked(buffer.data(), buffer.size(), ©);
if (result == SR_SUCCESS) {
// If write was successful then adjust the number of readable bytes.
data_length_ += copy;
bytes_written = copy;
// if we didn't have any data to read before, and now we do, post an event
if (!was_readable && copy > 0) {
PostEvent(SE_READ, 0);
}
}
return result;
}
void FifoBuffer::Close() {
webrtc::MutexLock lock(&mutex_);
state_ = SS_CLOSED;
}
const void* FifoBuffer::GetReadData(size_t* size) {
webrtc::MutexLock lock(&mutex_);
*size = (read_position_ + data_length_ <= buffer_length_)
? data_length_
: buffer_length_ - read_position_;
return &buffer_[read_position_];
}
void FifoBuffer::ConsumeReadData(size_t size) {
webrtc::MutexLock lock(&mutex_);
RTC_DCHECK(size <= data_length_);
const bool was_writable = data_length_ < buffer_length_;
read_position_ = (read_position_ + size) % buffer_length_;
data_length_ -= size;
if (!was_writable && size > 0) {
PostEvent(SE_WRITE, 0);
}
}
void* FifoBuffer::GetWriteBuffer(size_t* size) {
webrtc::MutexLock lock(&mutex_);
if (state_ == SS_CLOSED) {
return nullptr;
}
// if empty, reset the write position to the beginning, so we can get
// the biggest possible block
if (data_length_ == 0) {
read_position_ = 0;
}
const size_t write_position =
(read_position_ + data_length_) % buffer_length_;
*size = (write_position > read_position_ || data_length_ == 0)
? buffer_length_ - write_position
: read_position_ - write_position;
return &buffer_[write_position];
}
void FifoBuffer::ConsumeWriteBuffer(size_t size) {
webrtc::MutexLock lock(&mutex_);
RTC_DCHECK(size <= buffer_length_ - data_length_);
const bool was_readable = (data_length_ > 0);
data_length_ += size;
if (!was_readable && size > 0) {
PostEvent(SE_READ, 0);
}
}
StreamResult FifoBuffer::ReadLocked(void* buffer,
size_t bytes,
size_t* bytes_read) {
if (data_length_ == 0) {
return (state_ != SS_CLOSED) ? SR_BLOCK : SR_EOS;
}
const size_t available = data_length_;
const size_t read_position = read_position_ % buffer_length_;
const size_t copy = std::min(bytes, available);
const size_t tail_copy = std::min(copy, buffer_length_ - read_position);
char* const p = static_cast<char*>(buffer);
memcpy(p, &buffer_[read_position], tail_copy);
memcpy(p + tail_copy, &buffer_[0], copy - tail_copy);
if (bytes_read) {
*bytes_read = copy;
}
return SR_SUCCESS;
}
StreamResult FifoBuffer::WriteLocked(const void* buffer,
size_t bytes,
size_t* bytes_written) {
if (state_ == SS_CLOSED) {
return SR_EOS;
}
if (data_length_ >= buffer_length_) {
return SR_BLOCK;
}
const size_t available = buffer_length_ - data_length_;
const size_t write_position =
(read_position_ + data_length_) % buffer_length_;
const size_t copy = std::min(bytes, available);
const size_t tail_copy = std::min(copy, buffer_length_ - write_position);
const char* const p = static_cast<const char*>(buffer);
memcpy(&buffer_[write_position], p, tail_copy);
memcpy(&buffer_[0], p + tail_copy, copy - tail_copy);
if (bytes_written) {
*bytes_written = copy;
}
return SR_SUCCESS;
}
} // namespace rtc
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