#include "aud_file.h"

AudFile::AudFile(QObject *parent) : QFile(parent)
{
    offset = 0;
}

AudFile::~AudFile()
{
    close();
}

bool AudFile::openFile(const QString &path)
{
    close();

    setFileName(path);

    bool ret = open(QFile::ReadOnly);

    if (ret)
    {
        offset = 0;

        if (peek(3) == "ID3")
        {
            QByteArray header   = read(10);
            QByteArray intBytes = header.mid(6);
            quint64    num      = 0;
            quint64    bit      = 1;

            offset += 10;

            if (header[5] & 16)   //Footer flag check
            {
                offset += 10;
            }

            for (int i = intBytes.size() - 1; i >= 0; --i)
            {
                int byte = intBytes[i];

                for (int inBit = 1; inBit <= 64; inBit *= 2, bit *= 2)
                {
                    if ((byte & inBit) != 0) num |= bit;
                }
            }

            offset += num;
        }

        seek(0);
    }

    return ret;
}

bool AudFile::seek(qint64 off)
{
    return QFile::seek(offset + off);
}

qint64 AudFile::size() const
{
    return QFile::size() - offset;
}