wavfile.cpp

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/*****************************************************************************
    NumeRe: Framework fuer Numerische Rechnungen
    Copyright (C) 2021  Erik Haenel et al.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
******************************************************************************/
 
#include "wavfile.hpp"
#include <cstring>
 
#define PCM 0x0001
 
namespace Audio
{
    static double convertFromUnsigned(double val)
    {
        return val > 1.0 ? val-2.0 : val;
    }
 
 
    static double getMaxVal(uint16_t bitdepth)
    {
        return (1 << (bitdepth-1)) - 1;
    }
 
    WavFile::WavFile(const std::string& sFileName)
    {
        m_WavFileStream.open(sFileName.c_str(), std::ios_base::in | std::ios_base::binary);
        sName = sFileName;
 
        if (!readHeader())
            m_WavFileStream.close();
    }
 
 
    WavFile::~WavFile()
    {
        closeFile();
    }
 
 
    bool WavFile::readHeader()
    {
        if (!m_WavFileStream.good())
        {
            m_DataBlockLength = 0;
            return false;
        }
        else
        {
            char headerInfo[5] = {0,0,0,0,0};
            m_WavFileStream.read(headerInfo, 4);
 
            if (strcmp(headerInfo, "RIFF"))
            {
                m_DataBlockLength = 0;
                return false;
            }
 
            m_WavFileStream.read(headerInfo, 4);
            m_WavFileStream.read(headerInfo, 4);
 
            if (strcmp(headerInfo, "WAVE"))
            {
                m_DataBlockLength = 0;
                return false;
            }
 
            m_WavFileStream.seekg(20);
            m_WavFileStream.read((char*)&m_Header, sizeof(WavFileHeader));
 
            if (m_Header.formatTag != PCM)
            {
                m_DataBlockLength = 0;
                return false;
            }
 
            m_WavFileStream.seekg(40);
            m_WavFileStream.read((char*)&m_DataBlockLength, 4);
        }
 
        return true;
    }
 
 
    void WavFile::closeFile()
    {
        if (m_WavFileStream.is_open())
        {
            m_WavFileStream.seekp(0, std::ios_base::end);
            uint32_t pos = m_WavFileStream.tellp()-8LL;
            m_WavFileStream.seekp(4);
            m_WavFileStream.write((char*)&pos, 4);
            m_WavFileStream.seekp(40);
            pos -= 36;
            m_WavFileStream.write((char*)&pos, 4);
            m_WavFileStream.close();
        }
    }
 
 
    void WavFile::newFile()
    {
        closeFile();
 
        // prepare header
        m_Header.formatTag = PCM;
        m_Header.bitsPerSample = 16;
        m_Header.bytesPerSecond = m_Header.sampleRate * m_Header.bitsPerSample / 8 * m_Header.channels;
        m_Header.blockAlign = m_Header.bitsPerSample / 8 * m_Header.channels;
 
        m_WavFileStream.open(sName.c_str(), std::ios_base::out | std::ios_base::binary | std::ios_base::trunc);
        m_WavFileStream.write("RIFF    WAVEfmt ", 16);
        uint32_t nSize = 16;
        m_WavFileStream.write((char*)&nSize, 4);
        m_WavFileStream.write((char*)&m_Header, sizeof(WavFileHeader));
        m_WavFileStream.write("data    ", 8);
    }
 
 
    void WavFile::write(const Sample& sample)
    {
        if (m_WavFileStream.is_open() && m_WavFileStream.good())
        {
            int16_t channelvalue = sample.leftOrMono * getMaxVal(16);
            m_WavFileStream.write((char*)&channelvalue, 2);
 
            if (m_Header.channels > 1 && !std::isnan(sample.right))
            {
                channelvalue = sample.right * getMaxVal(16);
                m_WavFileStream.write((char*)&channelvalue, 2);
            }
        }
    }
 
 
    Sample WavFile::read() const
    {
        uint32_t samples[2] = {0,0};
 
        if (m_Header.channels == 1)
        {
            m_WavFileStream.read((char*)samples, m_Header.blockAlign);
            return Sample(convertFromUnsigned(samples[0] / getMaxVal(m_Header.bitsPerSample)));
        }
        else
        {
            m_WavFileStream.read((char*)&samples[0], m_Header.blockAlign/m_Header.channels);
            m_WavFileStream.read((char*)&samples[1], m_Header.blockAlign/m_Header.channels);
            return Sample(convertFromUnsigned(samples[0] / getMaxVal(m_Header.bitsPerSample)), convertFromUnsigned(samples[1] / getMaxVal(m_Header.bitsPerSample)));
        }
 
        return Sample(NAN);
    }
 
 
    std::vector<Sample> WavFile::readSome(size_t len) const
    {
        std::vector<Sample> vSamples;
 
        for (size_t i = 0; i < len; i++)
        {
            if (m_WavFileStream.eof() || !m_WavFileStream.good())
                break;
 
            vSamples.push_back(read());
        }
 
        return vSamples;
    }
 
 
    void WavFile::writeSome(const std::vector<Sample> vSamples)
    {
        for (const Sample& s : vSamples)
        {
            write(s);
        }
    }
}