#!/usr/bin/env python


def is_contiguous(memview, order='C'):
    """Returns true if the memory view passed is contiguous.

    Parameters
    ----------
    memview : memoryview
    order : {'C', 'F'}
        Memory layout which should be satisfied.
    """
    if order not in ('C', 'F'):
        raise ValueError("Only 'C' and 'F' are supported orders.")

    # These special cases are all 0 or 1-d so the order does not matter:
    if memview.ndim == 0:
        # Single element is always contiguous
        return True

    if memview.strides is None:
        return True
    if memview.shape is None:
        if memview.strides[0] == memview.itemsize:
            return True
        return False

    # The usual code when both strides and shape is not None:
    if order == 'C':
        # Invert C-order, so that first dimension should change slowest
        strides = memview.strides[::-1]
        shape = memview.shape[::-1]
    else:
        strides = memview.strides
        shape = memview.shape

    # The stride used by a contiguous buffer which follows from itemsize+shape
    expected_stride = memview.itemsize
    is_contiguous = True
    for i in range(memview.ndim):
        if shape[i] == 0:
            # A buffer without elements is always contiguous
            return True
        if shape[i] == 1:
            # If the shape is 1, the corresponding index is 0, so the stride
            # is not relavent for calculating memory offsets/the memory layout
            continue
        if strides[i] != expected_stride:
            is_contiguous = False
            # No return here, because buffer might be empty.

        expected_stride *= shape[i]

    return is_contiguous