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"""
utilities for the fits library
"""
import sys
import numpy
from . import _fitsio_wrap
if sys.version_info >= (3, 0, 0):
IS_PY3 = True
else:
IS_PY3 = False
class FITSRuntimeWarning(RuntimeWarning):
pass
def cfitsio_version(asfloat=False):
"""
Return the cfitsio version as a string.
"""
# use string version to avoid roundoffs
ver = '%0.3f' % _fitsio_wrap.cfitsio_version()
if asfloat:
return float(ver)
else:
return ver
if sys.version_info > (3, 0, 0):
_itypes = (int,)
_stypes = (str, bytes)
else:
_itypes = (int, long) # noqa - only for py2
_stypes = (basestring, unicode,) # noqa - only for py2
_itypes += (numpy.uint8, numpy.int8,
numpy.uint16, numpy.int16,
numpy.uint32, numpy.int32,
numpy.uint64, numpy.int64)
# different for py3
_stypes += (numpy.string_, numpy.str_)
# for header keywords
_ftypes = (float, numpy.float32, numpy.float64)
def isstring(arg):
return isinstance(arg, _stypes)
def isinteger(arg):
return isinstance(arg, _itypes)
def is_object(arr):
if arr.dtype.descr[0][1][1] == 'O':
return True
else:
return False
def fields_are_object(arr):
isobj = numpy.zeros(len(arr.dtype.names), dtype=bool)
for i, name in enumerate(arr.dtype.names):
if is_object(arr[name]):
isobj[i] = True
return isobj
def is_little_endian(array):
"""
Return True if array is little endian, False otherwise.
Parameters
----------
array: numpy array
A numerical python array.
Returns
-------
Truth value:
True for little-endian
Notes
-----
Strings are neither big or little endian. The input must be a simple numpy
array, not an array with fields.
"""
if numpy.little_endian:
machine_little = True
else:
machine_little = False
byteorder = array.dtype.base.byteorder
return (byteorder == '<') or (machine_little and byteorder == '=')
def array_to_native(array, inplace=False):
"""
Convert an array to the native byte order.
NOTE: the inplace keyword argument is not currently used.
"""
if numpy.little_endian:
machine_little = True
else:
machine_little = False
data_little = False
if array.dtype.names is None:
if array.dtype.base.byteorder == '|':
# strings and 1 byte integers
return array
data_little = is_little_endian(array)
else:
# assume all are same byte order: we only need to find one with
# little endian
for fname in array.dtype.names:
if is_little_endian(array[fname]):
data_little = True
break
if ((machine_little and not data_little)
or (not machine_little and data_little)):
output = array.byteswap(inplace)
else:
output = array
return output
def array_to_native_c(array_in, inplace=False):
# copy only made if not C order
arr = numpy.array(array_in, order='C', copy=False)
return array_to_native(arr, inplace=inplace)
def mks(val):
"""
make sure the value is a string, paying mind to python3 vs 2
"""
if sys.version_info > (3, 0, 0):
if isinstance(val, bytes):
sval = str(val, 'utf-8')
else:
sval = str(val)
else:
sval = str(val)
return sval
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