/// <summary>
/// Entity of .npy binary saving.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="stream"></param>
/// <param name="ndArray"></param>
/// <param name="dtype"></param>
/// <param name="writeAt"></param>
private static void SaveCore <T>(Stream stream, NdArray <T> ndArray, DType dtype,
Action <int, byte[]> writeAt)
{
var header = new NpyHeader(1, 0, dtype, false, ndArray.Shape);
var headerBytes = header.GenerateHeader();
var bufferSize = ndArray.Shape.TotalLength;
var buffer =
new byte[dtype.ByteSize * bufferSize ?? throw new NotSupportedException()];
/// <summary>
/// Loads <see cref="NdArray{T}"/> instance from .npy binary stream with using implicit cast.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="stream"></param>
/// <returns></returns>
/// <exception cref="NotSupportedException"></exception>
/// <exception cref="InvalidCastException"></exception>
public static NdArray <T> LoadAs <T>(Stream stream)
{
var header = NpyHeader.LoadHeader(stream);
switch (header.NumpyType.TypeKind)
{
case TypeKind.Boolean:
return(LoadCore <bool>(header, stream).Select(x => (T)(dynamic)x));
case TypeKind.UInt8:
return(LoadCore <byte>(header, stream).Select(x => (T)(dynamic)x));
case TypeKind.UInt16:
return(LoadCore <ushort>(header, stream).Select(x => (T)(dynamic)x));
case TypeKind.UInt32:
return(LoadCore <uint>(header, stream).Select(x => (T)(dynamic)x));
case TypeKind.UInt64:
return(LoadCore <ulong>(header, stream).Select(x => (T)(dynamic)x));
case TypeKind.Int8:
return(LoadCore <sbyte>(header, stream).Select(x => (T)(dynamic)x));
case TypeKind.Int16:
return(LoadCore <short>(header, stream).Select(x => (T)(dynamic)x));
case TypeKind.Int32:
return(LoadCore <int>(header, stream).Select(x => (T)(dynamic)x));
case TypeKind.Int64:
return(LoadCore <long>(header, stream).Select(x => (T)(dynamic)x));
case TypeKind.Float16:
throw new NotImplementedException();
case TypeKind.Float32:
return(LoadCore <float>(header, stream).Select(x => (T)(dynamic)x));
case TypeKind.Float64:
return(LoadCore <double>(header, stream).Select(x => (T)(dynamic)x));
case TypeKind.Unicode:
return(LoadCore <string>(header, stream).Select(x => (T)(dynamic)x));
default:
throw new InvalidOperationException();
}
}
/// <summary>
/// Loads <see cref="NdArray{T}"/> instance from .npy binary stream with strict type.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="stream"></param>
/// <returns></returns>
/// <exception cref="NotSupportedException"></exception>
/// <exception cref="InvalidCastException"></exception>
public static NdArray <T> Load <T>(Stream stream)
=> LoadCore <T>(NpyHeader.LoadHeader(stream), stream);
/// <summary>
/// Entity of .npy binary loading, excluding header loading.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="header"></param>
/// <param name="stream"></param>
/// <returns></returns>
private static NdArray <T> LoadCore <T>(NpyHeader header, Stream stream)
{
NotSupportedException unsupportedFileFormatError()
=> new NotSupportedException(".npy binary is unsupported format.");
InvalidCastException typeMismatchError()
=> new InvalidCastException("Generic type is mismatch with .npy binary.");
var byteSize = header.NumpyType.ByteSize ?? 0;
if (byteSize == 0)
{
throw unsupportedFileFormatError();
}
var totalLength = header.Shape.TotalLength;
var bufferSize = byteSize * totalLength;
T[] core <T2>(Func <int, T2> readAt)
{
if (typeof(T) != typeof(T2))
{
throw typeMismatchError();
}
T2[] retvalArray = new T2[totalLength];
for (var i = 0; i < totalLength; ++i)
{
retvalArray[i] = readAt(i);
}
return(retvalArray as T[]);
}
var shape = header.Shape;
var buffer = new byte[bufferSize];
stream.Read(buffer, 0, bufferSize);
var converter = header.NumpyType.Endian == Endian.Little
? LittleEndiannessBitConverter.Instance
: BigEndiannessBitConverter.Instance;
switch (header.NumpyType.TypeKind)
{
case TypeKind.Boolean:
return(NdArray.Create(core(i => buffer[i] > 0), shape));
case TypeKind.UInt8:
return(NdArray.Create(core(i => buffer[i]), shape));
case TypeKind.UInt16:
return(NdArray.Create(core(i => converter.ReadPrimitive <ushort>(buffer.AsSpan(2 * i))),
shape));
case TypeKind.UInt32:
return(NdArray.Create(core(i => converter.ReadPrimitive <uint>(buffer.AsSpan(4 * i))),
shape));
case TypeKind.UInt64:
return(NdArray.Create(core(i => converter.ReadPrimitive <ulong>(buffer.AsSpan(8 * i))),
shape));
case TypeKind.Int8:
return(NdArray.Create(core(i => (sbyte)buffer[i]), shape));
case TypeKind.Int16:
return(NdArray.Create(core(i => converter.ReadPrimitive <short>(buffer.AsSpan(2 * i))),
shape));
case TypeKind.Int32:
return(NdArray.Create(core(i => converter.ReadPrimitive <int>(buffer.AsSpan(4 * i))),
shape));
case TypeKind.Int64:
return(NdArray.Create(core(i => converter.ReadPrimitive <long>(buffer.AsSpan(8 * i))),
shape));
case TypeKind.Float16:
throw new NotImplementedException();
case TypeKind.Float32:
return(NdArray.Create(core(i => converter.ReadPrimitive <float>(buffer.AsSpan(4 * i))),
shape));
case TypeKind.Float64:
return(NdArray.Create(core(i => converter.ReadPrimitive <double>(buffer.AsSpan(8 * i))),
shape));
case TypeKind.Unicode:
return
(NdArray.Create(core(i => Encoding.UTF32.GetString(buffer, byteSize * i, byteSize)),
shape));
default:
throw unsupportedFileFormatError();
}
}
