public INifti <T> ReadNifti(string filepath)
{
using (var fileStream = new FileStream(filepath, FileMode.Open))
{
if (!fileStream.CanRead)
{
throw new IOException($"Unable to access file: {filepath}");
}
var isBigEndian = IsBigEndian(fileStream);
var reader = new BinaryReaderBigAndLittleEndian(fileStream, isBigEndian);
ReadNiftiHeader(reader);
var bytesLength = Convert.ToInt32(reader.BaseStream.Length) - Convert.ToInt32(Header.vox_offset);
Voxels = ReadVoxels(reader, bytesLength);
if (reader.BaseStream.Position != reader.BaseStream.Length)
{
throw new Exception("Not all bytes in the stream were read!");
}
}
return(this);
}
public void ReadNiftiHeader(string filepath)
{
using (var fileStream = new FileStream(filepath, FileMode.Open))
{
if (!fileStream.CanRead)
{
throw new IOException($"Unable to access file: {filepath}");
}
var isBigEndian = IsBigEndian(fileStream);
var reader = new BinaryReaderBigAndLittleEndian(fileStream, isBigEndian);
ReadNiftiHeader(reader);
}
}
private static bool IsBigEndian(Stream fileStream)
{
var reader = new BinaryReader(fileStream);
var headerSize = reader.ReadInt32();
if (headerSize != 348) // this means it might be big endian, but let's make sure it is
// (we should be able to check if we're reading 1543569408 and skip the extra read, but this way is less brittle)
{
fileStream.Position = 0;
var beReader = new BinaryReaderBigAndLittleEndian(fileStream, true);
headerSize = beReader.ReadInt32();
if (headerSize != 348)
{
throw new Exception("Either not a nifti File or type not supported! sizeof_hdr should be 348 for a nifti-1 file.");
}
fileStream.Position = 0;
return(true);
}
fileStream.Position = 0;
return(false);
}
