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extern/audaspace/src/fx/ReverseReader.cpp
- This file was added.
| /******************************************************************************* | |||||
| * Copyright 2009-2016 Jörg Müller | |||||
| * | |||||
| * 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 | |||||
| * | |||||
| * http://www.apache.org/licenses/LICENSE-2.0 | |||||
| * | |||||
| * 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 "fx/ReverseReader.h" | |||||
| #include "Exception.h" | |||||
| #include <cstring> | |||||
| AUD_NAMESPACE_BEGIN | |||||
| ReverseReader::ReverseReader(std::shared_ptr<IReader> reader) : | |||||
| EffectReader(reader), | |||||
| m_length(reader->getLength()), | |||||
| m_position(0) | |||||
| { | |||||
| if(m_length < 0 || !reader->isSeekable()) | |||||
| AUD_THROW(StateException, "A reader has to be seekable and have finite length to be reversible."); | |||||
| } | |||||
| void ReverseReader::seek(int position) | |||||
| { | |||||
| m_position = position; | |||||
| } | |||||
| int ReverseReader::getLength() const | |||||
| { | |||||
| return m_length; | |||||
| } | |||||
| int ReverseReader::getPosition() const | |||||
| { | |||||
| return m_position; | |||||
| } | |||||
| void ReverseReader::read(int& length, bool& eos, sample_t* buffer) | |||||
| { | |||||
| // first correct the length | |||||
| if(m_position + length > m_length) | |||||
| length = m_length - m_position; | |||||
| if(length <= 0) | |||||
| { | |||||
| length = 0; | |||||
| eos = true; | |||||
| return; | |||||
| } | |||||
| const Specs specs = getSpecs(); | |||||
| const int samplesize = AUD_SAMPLE_SIZE(specs); | |||||
| sample_t temp[CHANNEL_MAX]; | |||||
| int len = length; | |||||
| // read from reader | |||||
| m_reader->seek(m_length - m_position - len); | |||||
| m_reader->read(len, eos, buffer); | |||||
| // set null if reader didn't give enough data | |||||
| if(len < length) | |||||
| std::memset(buffer, 0, (length - len) * samplesize); | |||||
| // copy the samples reverted | |||||
| for(int i = 0; i < length / 2; i++) | |||||
| { | |||||
| std::memcpy(temp, buffer + (len - 1 - i) * specs.channels, samplesize); | |||||
| std::memcpy(buffer + (len - 1 - i) * specs.channels, buffer + i * specs.channels, samplesize); | |||||
| std::memcpy(buffer + i * specs.channels, temp, samplesize); | |||||
| } | |||||
| m_position += length; | |||||
| eos = false; | |||||
| } | |||||
| AUD_NAMESPACE_END | |||||