diff options
Diffstat (limited to 'extern/audaspace/src/respec/LinearResampleReader.cpp')
| -rw-r--r-- | extern/audaspace/src/respec/LinearResampleReader.cpp | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/extern/audaspace/src/respec/LinearResampleReader.cpp b/extern/audaspace/src/respec/LinearResampleReader.cpp new file mode 100644 index 00000000000..53d506115ce --- /dev/null +++ b/extern/audaspace/src/respec/LinearResampleReader.cpp @@ -0,0 +1,174 @@ +/******************************************************************************* + * 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 "respec/LinearResampleReader.h" + +#include <cmath> +#include <cstring> + +AUD_NAMESPACE_BEGIN + +LinearResampleReader::LinearResampleReader(std::shared_ptr<IReader> reader, SampleRate rate) : + ResampleReader(reader, rate), + m_channels(reader->getSpecs().channels), + m_cache_pos(0), + m_cache_ok(false) +{ + Specs specs = { rate, m_channels }; + m_cache.resize(2 * AUD_SAMPLE_SIZE(specs)); +} + +void LinearResampleReader::seek(int position) +{ + position = std::floor(position * double(m_reader->getSpecs().rate) / double(m_rate)); + m_reader->seek(position); + m_cache_ok = false; + m_cache_pos = 0; +} + +int LinearResampleReader::getLength() const +{ + return std::floor(m_reader->getLength() * double(m_rate) / double(m_reader->getSpecs().rate)); +} + +int LinearResampleReader::getPosition() const +{ + return std::floor((m_reader->getPosition() + (m_cache_ok ? m_cache_pos - 1 : 0)) + * m_rate / m_reader->getSpecs().rate); +} + +Specs LinearResampleReader::getSpecs() const +{ + Specs specs = m_reader->getSpecs(); + specs.rate = m_rate; + return specs; +} + +void LinearResampleReader::read(int& length, bool& eos, sample_t* buffer) +{ + if(length == 0) + return; + + Specs specs = m_reader->getSpecs(); + + int samplesize = AUD_SAMPLE_SIZE(specs); + int size = length; + float factor = m_rate / m_reader->getSpecs().rate; + float spos = 0.0f; + sample_t low, high; + eos = false; + + // check for channels changed + + if(specs.channels != m_channels) + { + m_cache.resize(2 * samplesize); + m_channels = specs.channels; + m_cache_ok = false; + } + + if(factor == 1 && (!m_cache_ok || m_cache_pos == 1)) + { + // can read directly! + m_reader->read(length, eos, buffer); + + if(length > 0) + { + std::memcpy(m_cache.getBuffer() + m_channels, buffer + m_channels * (length - 1), samplesize); + m_cache_pos = 1; + m_cache_ok = true; + } + + return; + } + + int len; + sample_t* buf; + + if(m_cache_ok) + { + int need = std::ceil(length / factor + m_cache_pos) - 1; + + len = need; + + m_buffer.assureSize((len + 2) * samplesize); + buf = m_buffer.getBuffer(); + + std::memcpy(buf, m_cache.getBuffer(), 2 * samplesize); + m_reader->read(len, eos, buf + 2 * m_channels); + + if(len < need) + length = std::floor((len + 1 - m_cache_pos) * factor); + } + else + { + m_cache_pos = 1 - 1 / factor; + + int need = std::ceil(length / factor + m_cache_pos); + + len = need; + + m_buffer.assureSize((len + 1) * samplesize); + buf = m_buffer.getBuffer(); + + std::memset(buf, 0, samplesize); + m_reader->read(len, eos, buf + m_channels); + + if(len == 0) + { + length = 0; + return; + } + + if(len < need) + { + length = std::floor((len - m_cache_pos) * factor); + } + + m_cache_ok = true; + } + + if(length == 0) + return; + + for(int channel = 0; channel < m_channels; channel++) + { + for(int i = 0; i < length; i++) + { + spos = (i + 1) / factor + m_cache_pos; + + low = buf[(int)std::floor(spos) * m_channels + channel]; + high = buf[(int)std::ceil(spos) * m_channels + channel]; + + buffer[i * m_channels + channel] = low + (spos - std::floor(spos)) * (high - low); + } + } + + if(std::floor(spos) == spos) + { + std::memcpy(m_cache.getBuffer() + m_channels, buf + int(std::floor(spos)) * m_channels, samplesize); + m_cache_pos = 1; + } + else + { + std::memcpy(m_cache.getBuffer(), buf + int(std::floor(spos)) * m_channels, 2 * samplesize); + m_cache_pos = spos - std::floor(spos); + } + + eos &= length < size; +} + +AUD_NAMESPACE_END |