/// <summary>
/// Function to determine if this codec can read the font data within the stream or not.
/// </summary>
/// <param name="stream">The stream that is used to read the font data.</param>
/// <returns><b>true</b> if the codec can read the file, <b>false</b> if not.</returns>
/// <exception cref="ArgumentNullException">Thrown when the <paramref name="stream"/> parameter is <b>null</b>.</exception>
/// <exception cref="IOException">Thrown when the <paramref name="stream"/> is write-only or if the stream cannot perform seek operations.</exception>
/// <exception cref="EndOfStreamException">Thrown when an attempt to read beyond the end of the stream is made.</exception>
/// <remarks>
/// <para>
/// Implementors should ensure that the stream position is restored prior to exiting this method. Failure to do so may cause problems when reading the data from the stream.
/// </para>
/// </remarks>
public override bool IsReadable(Stream stream)
{
ulong fileHeaderID = FileHeader.ChunkID();
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
if (!stream.CanRead)
{
throw new IOException(Resources.GORGFX_ERR_STREAM_WRITE_ONLY);
}
if (!stream.CanSeek)
{
throw new IOException(Resources.GORGFX_ERR_STREAM_NO_SEEK);
}
if (stream.Length - stream.Position < FileHeader.Length)
{
return(false);
}
long position = stream.Position;
var reader = new GorgonBinaryReader(stream, true);
try
{
ulong fileData = reader.ReadUInt64();
return(fileData == fileHeaderID);
}
finally
{
reader.Dispose();
stream.Position = position;
}
}
