private void ReadChunkCrc(PngChunk chunk, byte[] typeBuffer)
{
byte[] crcBuffer = new byte[4];
int numBytes = currentStream.Read(crcBuffer, 0, 4);
if (numBytes >= 1 && numBytes <= 3)
{
throw new Exception("Image stream is not valid!");
}
Array.Reverse(crcBuffer);
chunk.Crc = BitConverter.ToUInt32(crcBuffer, 0);
Crc32 crc = new Crc32();
crc.Update(typeBuffer);
crc.Update(chunk.Data);
if (crc.Value != chunk.Crc)
{
throw new Exception("CRC Error. Png Image chunk is corrupt!");
}
}
private void ReadChunkData(PngChunk chunk)
{
chunk.Data = new byte[chunk.Length];
currentStream.Read(chunk.Data, 0, chunk.Length);
}