/// <summary>
/// Modify the ChunkData part.
/// </summary>
public void ModifyChunkData(int position, byte[] newData)
{
Array.Copy(newData, 0, ChunkData, position, newData.Length);
using (var msCrc = new MemoryStream())
{
msCrc.WriteBytes(Encoding.ASCII.GetBytes(ChunkType));
msCrc.WriteBytes(ChunkData);
Crc = CrcHelper.Calculate(msCrc.ToArray());
}
}
public IDATChunk ToIDATChunk()
{
uint newCrc;
using (var msCrc = new MemoryStream())
{
msCrc.WriteBytes(new[] { (byte)'I', (byte)'D', (byte)'A', (byte)'T' });
msCrc.WriteBytes(FrameData);
newCrc = CrcHelper.Calculate(msCrc.ToArray());
}
using (var ms = new MemoryStream())
{
ms.WriteUInt32(Helper.ConvertEndian(Length - 4));
ms.WriteBytes(new[] { (byte)'I', (byte)'D', (byte)'A', (byte)'T' });
ms.WriteBytes(FrameData);
ms.WriteUInt32(Helper.ConvertEndian(newCrc));
ms.Position = 0;
return(new IDATChunk(ms));
}
}
