public static Header ReadHeader(BinaryReader reader, out int headerSize)
{
var magicBytes = reader.ReadBytes(8);
if (!magicBytes.SequenceEqual(Constants.MagicBytes))
{
throw new Exception("Not a FlatGeobuf file");
}
headerSize = reader.ReadInt32();
var header = Header.GetRootAsHeader(new ByteBuffer(reader.ReadBytes(headerSize)));
return(header);
}
/// <summary>
/// Reads the header of a FlatGeobuf stream
/// </summary>
/// <param name="stream">The FlatGeobuf stream</param>
/// <returns>The header</returns>
/// <exception cref="InvalidDataException">Thrown if the stream does not contain FlatGeobuf data</exception>
internal static async ValueTask <HeaderT> ReadHeaderAsync(Stream stream, CancellationToken token)
{
byte[] smallBuffer = new byte[8];
// Read & check magic bytes
int numRead = await stream.ReadAsync(smallBuffer, 0, 8, token);
if (numRead != 8)
{
throw new InvalidDataException("Insufficient stream size");
}
if (!smallBuffer.Take(4).SequenceEqual(Constants.MagicBytes.Take(4)))
{
throw new InvalidDataException("Not a FlatGeobuf stream");
}
// Read header size
numRead = await stream.ReadAsync(smallBuffer, 0, 4, token);
if (numRead != 4)
{
throw new InvalidDataException("Insufficient stream size");
}
int headerSize = MemoryMarshal.Read <int>(smallBuffer);
// Rent a buffer and read header data
byte[] headerData = ArrayPool <byte> .Shared.Rent(headerSize);
numRead = await stream.ReadAsync(headerData, 0, headerSize, token);
if (numRead != headerSize)
{
throw new InvalidDataException("Insufficient stream size");
}
// Parse header, return buffer
var header = Header.GetRootAsHeader(new ByteBuffer(headerData, 0)).UnPack();
ArrayPool <byte> .Shared.Return(headerData);
return(header);
}
public static HeaderT DeserializeFromBinary(byte[] fbBuffer)
{
return(Header.GetRootAsHeader(new ByteBuffer(fbBuffer)).UnPack());
}
