public int __hash__(CodeContext context)
{
if (_storedHash != null)
{
return(_storedHash.Value);
}
CheckBuffer();
if (!_isReadOnly)
{
throw PythonOps.ValueError("cannot hash writable memoryview object");
}
TypecodeOps.DecomposeTypecode(_format, out _, out char typecode);
if (!TypecodeOps.IsByteCode(typecode))
{
throw PythonOps.ValueError("memoryview: hashing is restricted to formats 'B', 'b' or 'c'");
}
_storedHash = tobytes().GetHashCode();
return(_storedHash.Value);
}
public MemoryView cast([NotNull] string format, [NotNull, AllowNull] object shape)
{
if (!_isCContig)
{
throw PythonOps.TypeError("memoryview: casts are restricted to C-contiguous views");
}
if (_shape.Contains(0) || _strides.Contains(0))
{
throw PythonOps.TypeError("memoryview: cannot cast view with zeros in shape or strides");
}
PythonTuple?shapeAsTuple = null;
if (shape != null)
{
if (!(shape is PythonList) && !(shape is PythonTuple))
{
throw PythonOps.TypeError("shape must be a list or a tuple");
}
shapeAsTuple = PythonTuple.Make(shape);
int newNDim = shapeAsTuple.Count;
if (newNDim > MaximumDimensions)
{
throw PythonOps.TypeError("memoryview: number of dimensions must not exceed {0}", MaximumDimensions);
}
if (_numDims != 1 && newNDim != 1)
{
throw PythonOps.TypeError("memoryview: cast must be 1D -> ND or ND -> 1D");
}
}
if (!TypecodeOps.TryDecomposeTypecode(format, out char byteorder, out char typecode) ||
!IsSupportedTypecode(typecode) ||
byteorder != '@'
)
{
throw PythonOps.ValueError(
"memoryview: destination format must be a native single character format prefixed with an optional '@'");
}
if (!TypecodeOps.IsByteCode(typecode))
{
TypecodeOps.DecomposeTypecode(_format, out _, out char thisTypecode);
if (!TypecodeOps.IsByteCode(thisTypecode))
{
throw PythonOps.TypeError("memoryview: cannot cast between two non-byte formats");
}
}
int newItemsize = TypecodeOps.GetTypecodeWidth(typecode);
if ((_numItems * _itemSize) % newItemsize != 0)
{
throw PythonOps.TypeError("memoryview: length is not a multiple of itemsize");
}
int newLength = _numItems * _itemSize / newItemsize;
int[] newShape;
if (shapeAsTuple != null)
{
newShape = new int[shapeAsTuple.Count];
int lengthGivenShape = 1;
for (int i = 0; i < shapeAsTuple.Count; i++)
{
newShape[i] = Converter.ConvertToInt32(shapeAsTuple[i]);
lengthGivenShape *= newShape[i];
}
if (lengthGivenShape != newLength)
{
throw PythonOps.TypeError("memoryview: product(shape) * itemsize != buffer size");
}
}
else
{
newShape = new int[] { newLength };
}
return(new MemoryView(this, format, newItemsize, newShape));
}
