"""

Miscellaneous utils.

"""

from numpy._core import asarray

from numpy._core.numeric import normalize_axis_index, normalize_axis_tuple

from numpy._utils import set_module

__all__ = ["byte_bounds", "normalize_axis_tuple", "normalize_axis_index"]

@set_module("numpy.lib.array_utils")

def byte_bounds(a):

"""

Returns pointers to the end-points of an array.

Parameters

----------

a : ndarray

Input array. It must conform to the Python-side of the array

interface.

Returns

-------

(low, high) : tuple of 2 integers

The first integer is the first byte of the array, the second

integer is just past the last byte of the array. If `a` is not

contiguous it will not use every byte between the (`low`, `high`)

values.

Examples

--------

>>> import numpy as np

>>> I = np.eye(2, dtype=np.float32); I.dtype

dtype('float32')

>>> low, high = np.lib.array_utils.byte_bounds(I)

>>> high - low == I.size*I.itemsize

True

>>> I = np.eye(2); I.dtype

dtype('float64')

>>> low, high = np.lib.array_utils.byte_bounds(I)

>>> high - low == I.size*I.itemsize

True

"""

ai = a.__array_interface__

a_data = ai['data'][0]

astrides = ai['strides']

ashape = ai['shape']

bytes_a = asarray(a).dtype.itemsize

a_low = a_high = a_data

if astrides is None:

# contiguous case

a_high += a.size * bytes_a

else:

for shape, stride in zip(ashape, astrides):

if stride < 0:

a_low += (shape - 1) * stride

else:

a_high += (shape - 1) * stride

a_high += bytes_a

return a_low, a_high