private void EncodeBlockLeading()
{
ushort periodCount = (ushort)((GenerateFrequenyFromOffset(FreqLeading) * m_LeadingLength + 500) / 1000);
DirectDigitalSyntheser.GenerateSilence(m_GapLeading, m_OutputWaves);
DirectDigitalSyntheser.GenerateSignal(GenerateFrequenyFromOffset(FreqLeading), periodCount, m_OutputWaves);
DirectDigitalSyntheser.GenerateSignal(GenerateFrequenyFromOffset(FreqSync), 1, m_OutputWaves);
}
private void GenerateDataBlock(byte[] programbytes)
{
byte sectorCount = (byte)((programbytes.Length + 255) / 256);
byte sectorIndex = 1;
m_CrcGenerator.GeneratedCrcValue = 0;
EncodeBlockLeading();
TapeBlockHeader blockHeader =
new TapeBlockHeader(m_CopyProtect)
{
SectorsInBlock = (byte)((programbytes.Length + 255) / 256)
};
m_CrcGenerator.AddBlock(blockHeader.ToByteArray(false));
EncodeBlock(blockHeader.ToByteArray());
while (sectorIndex <= sectorCount)
{
int sectorSize = programbytes.Length - 256 * (sectorIndex - 1);
if (sectorSize > 255)
{
sectorSize = 256;
}
TapeSectorHeader sectorHeader = new TapeSectorHeader
{
SectorNumber = sectorIndex,
BytesInSector = (byte)(sectorSize > 255 ? 0 : (byte)sectorSize)
};
m_CrcGenerator.AddBlock(sectorHeader.ToByteArray());
EncodeBlock(sectorHeader.ToByteArray());
byte[] sectorData = new byte[sectorSize];
int sourceIndex = (sectorIndex - 1) * 256;
Array.Copy(programbytes, sourceIndex, sectorData, 0, sectorSize);
m_CrcGenerator.AddBlock(sectorData);
EncodeBlock(sectorData);
TapeSectorEnd sectorEnd =
new TapeSectorEnd {
EofFlag = (byte)(sectorIndex == sectorCount ? 0xff : 0x00)
};
m_CrcGenerator.AddByte(sectorEnd.EofFlag);
sectorEnd.Crc = m_CrcGenerator.GeneratedCrcValue;
EncodeBlock(sectorEnd.ToByteArray());
m_CrcGenerator.GeneratedCrcValue = 0;
sectorIndex++;
}
DirectDigitalSyntheser.GenerateSignal(GenerateFrequenyFromOffset(FreqLeading), 5, m_OutputWaves);
DirectDigitalSyntheser.GenerateSilence(50, m_OutputWaves);
}
private void EncodeByte(byte data)
{
for (int i = 0; i < 8; i++)
{
DirectDigitalSyntheser.GenerateSignal(
(data & 0x01) == 0
? GenerateFrequenyFromOffset(ZeroFreqValue)
: GenerateFrequenyFromOffset(OneFreqValue), 1, m_OutputWaves);
data >>= 1;
}
}
private void GenerateHeaderBlock(int programlength)
{
// block leading
EncodeBlockLeading();
TapeBlockHeader blockHeader = new TapeBlockHeader(m_CopyProtect)
{
BlockType = 0xff, // Header block
SectorsInBlock = 1
};
m_CrcGenerator.AddBlock(blockHeader.ToByteArray(false));
EncodeBlock(blockHeader.ToByteArray());
TapeSectorHeader sectorHeader = new TapeSectorHeader
{
SectorNumber = 0,
BytesInSector = (byte)(m_FileName.Length + m_CasHeader.ToByteArray().Length + 1)
};
m_CrcGenerator.AddBlock(sectorHeader.ToByteArray());
EncodeBlock(sectorHeader.ToByteArray());
m_CrcGenerator.AddByte((byte)m_FileName.Length);
EncodeByte((byte)m_FileName.Length);
byte[] asciiFileName = Encoding.ASCII.GetBytes(m_FileName);
m_CrcGenerator.AddBlock(asciiFileName);
EncodeBlock(asciiFileName);
m_CasHeader.FileLength = (ushort)programlength;
m_CrcGenerator.AddBlock(m_CasHeader.ToByteArray());
EncodeBlock(m_CasHeader.ToByteArray());
TapeSectorEnd sectorEnd = new TapeSectorEnd
{
EofFlag = 0x00,
};
m_CrcGenerator.AddByte(sectorEnd.EofFlag);
sectorEnd.Crc = m_CrcGenerator.GeneratedCrcValue;
EncodeBlock(sectorEnd.ToByteArray());
DirectDigitalSyntheser.GenerateSignal(GenerateFrequenyFromOffset(FreqLeading), 5, m_OutputWaves);
}