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/*
Copyright 2018 Google Inc. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS-IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
#include "dsp/circular_buffer.h"
#include <algorithm>
#include "base/constants_and_types.h"
namespace vraudio {
CircularBuffer::CircularBuffer(size_t buffer_length, size_t num_input_frames,
size_t num_output_frames)
: num_input_frames_(num_input_frames),
num_output_frames_(num_output_frames),
buffer_(kNumMonoChannels, buffer_length),
write_cursor_(0),
read_cursor_(0),
num_valid_frames_(0) {
CHECK_GE(buffer_length, num_input_frames + num_output_frames);
}
bool CircularBuffer::InsertBuffer(const AudioBuffer::Channel& input) {
DCHECK_EQ(input.size(), num_input_frames_);
if (num_valid_frames_ + num_input_frames_ > buffer_.num_frames()) {
return false;
}
// Remaining space after the write cursor.
const size_t forward_write_space = read_cursor_ <= write_cursor_
? buffer_.num_frames() - write_cursor_
: read_cursor_ - write_cursor_;
// Copy the input into the buffer.
AudioBuffer::Channel* buffer_channel = &buffer_[0];
if (forward_write_space >= num_input_frames_) {
DCHECK_LE(buffer_channel->begin() + write_cursor_ + num_input_frames_,
buffer_channel->end());
std::copy(input.begin(), input.end(),
buffer_channel->begin() + write_cursor_);
} else {
DCHECK_LE(buffer_channel->begin() + write_cursor_ + forward_write_space,
buffer_channel->end());
DCHECK_LT(input.begin() + forward_write_space, input.end());
std::copy(input.begin(), input.begin() + forward_write_space,
buffer_channel->begin() + write_cursor_);
DCHECK_LE(buffer_channel->begin() + forward_write_space,
buffer_channel->end());
std::copy(input.begin() + forward_write_space, input.end(),
buffer_channel->begin());
}
write_cursor_ = (write_cursor_ + num_input_frames_) % buffer_.num_frames();
num_valid_frames_ += num_input_frames_;
return true;
}
bool CircularBuffer::RetrieveBuffer(AudioBuffer::Channel* output) {
return RetrieveBufferWithOffset(/*offset=*/0, output);
}
bool CircularBuffer::RetrieveBufferWithOffset(size_t offset,
AudioBuffer::Channel* output) {
DCHECK_LE(output->begin() + num_output_frames_ + offset, output->end());
if (num_valid_frames_ < num_output_frames_) {
return false;
}
// Remaining space after the read cursor.
const size_t forward_read_space = read_cursor_ < write_cursor_
? write_cursor_ - read_cursor_
: buffer_.num_frames() - read_cursor_;
// Copy the buffer values into the output.
AudioBuffer::Channel* buffer_channel = &buffer_[0];
if (forward_read_space >= num_output_frames_) {
DCHECK_LE(buffer_channel->begin() + read_cursor_ + num_output_frames_,
buffer_channel->end());
std::copy(buffer_channel->begin() + read_cursor_,
buffer_channel->begin() + read_cursor_ + num_output_frames_,
output->begin() + offset);
} else {
DCHECK_LE(buffer_channel->begin() + read_cursor_ + forward_read_space,
buffer_channel->end());
DCHECK_LE(output->begin() + forward_read_space + offset, output->end());
std::copy(buffer_channel->begin() + read_cursor_,
buffer_channel->begin() + read_cursor_ + forward_read_space,
output->begin() + offset);
DCHECK_GE(buffer_channel->begin() + num_output_frames_ - forward_read_space,
buffer_channel->begin());
DCHECK_LE(output->begin() + offset + num_output_frames_, output->end());
std::copy(buffer_channel->begin(),
buffer_channel->begin() + num_output_frames_ - forward_read_space,
output->begin() + offset + forward_read_space);
}
read_cursor_ = (read_cursor_ + num_output_frames_) % buffer_.num_frames();
num_valid_frames_ -= num_output_frames_;
return true;
}
void CircularBuffer::Clear() {
read_cursor_ = 0;
write_cursor_ = 0;
num_valid_frames_ = 0;
}
} // namespace vraudio