def readarray(self, size=None, offset=0, dtype=np.uint8, shape=None):
"""
Similar to file.read(), but returns the contents of the underlying
file as a numpy array (or mmap'd array if memmap=True) rather than a
string.
Usually it's best not to use the `size` argument with this method, but
it's provided for compatibility.
"""
if not hasattr(self.__file, 'read'):
raise EOFError
if not isinstance(dtype, np.dtype):
dtype = np.dtype(dtype)
if size and size % dtype.itemsize != 0:
raise ValueError('size %d not a multiple of %s' % (size, dtype))
if isinstance(shape, int):
shape = (shape, )
if size and shape:
actualsize = sum(dim * dtype.itemsize for dim in shape)
if actualsize < size:
raise ValueError('size %d is too few bytes for a %s array of '
'%s' % (size, shape, dtype))
if actualsize < size:
raise ValueError('size %d is too many bytes for a %s array of '
'%s' % (size, shape, dtype))
if size and not shape:
shape = (size // dtype.itemsize, )
if not (size or shape):
warnings.warn(
'No size or shape given to readarray(); assuming a '
'shape of (1,)', AstropyUserWarning)
shape = (1, )
if self.memmap:
return Memmap(self.__file,
offset=offset,
mode=MEMMAP_MODES[self.mode],
dtype=dtype,
shape=shape).view(np.ndarray)
else:
count = reduce(lambda x, y: x * y, shape)
pos = self.__file.tell()
self.__file.seek(offset)
data = _array_from_file(self.__file, dtype, count, '')
data.shape = shape
self.__file.seek(pos)
return data
def readarray(self, size=None, offset=0, dtype=np.uint8, shape=None):
"""
Similar to file.read(), but returns the contents of the underlying
file as a numpy array (or mmap'd array if memmap=True) rather than a
string.
Usually it's best not to use the `size` argument with this method, but
it's provided for compatibility.
"""
if not hasattr(self._file, 'read'):
raise EOFError
if not isinstance(dtype, np.dtype):
dtype = np.dtype(dtype)
if size and size % dtype.itemsize != 0:
raise ValueError('size {} not a multiple of {}'.format(size, dtype))
if isinstance(shape, int):
shape = (shape,)
if not (size or shape):
warnings.warn('No size or shape given to readarray(); assuming a '
'shape of (1,)', AstropyUserWarning)
shape = (1,)
if size and not shape:
shape = (size // dtype.itemsize,)
if size and shape:
actualsize = np.prod(shape) * dtype.itemsize
if actualsize < size:
raise ValueError('size {} is too few bytes for a {} array of '
'{}'.format(size, shape, dtype))
if actualsize < size:
raise ValueError('size {} is too many bytes for a {} array of '
'{}'.format(size, shape, dtype))
filepos = self._file.tell()
try:
if self.memmap:
if self._mmap is None:
# Instantiate Memmap array of the file offset at 0 (so we
# can return slices of it to offset anywhere else into the
# file)
memmap = Memmap(self._file, mode=MEMMAP_MODES[self.mode],
dtype=np.uint8)
# Now we immediately discard the memmap array; we are
# really just using it as a factory function to instantiate
# the mmap object in a convenient way (may later do away
# with this usage)
self._mmap = memmap.base
# Prevent dorking with self._memmap._mmap by memmap.__del__
# in Numpy 1.6 (see
# https://github.com/numpy/numpy/commit/dcc355a0b179387eeba10c95baf2e1eb21d417c7)
memmap._mmap = None
del memmap
return np.ndarray(shape=shape, dtype=dtype, offset=offset,
buffer=self._mmap)
else:
count = reduce(operator.mul, shape)
self._file.seek(offset)
data = _array_from_file(self._file, dtype, count, '')
data.shape = shape
return data
finally:
# Make sure we leave the file in the position we found it; on
# some platforms (e.g. Windows) mmaping a file handle can also
# reset its file pointer
self._file.seek(filepos)
def readarray(self, size=None, offset=0, dtype=np.uint8, shape=None):
"""
Similar to file.read(), but returns the contents of the underlying
file as a numpy array (or mmap'd array if memmap=True) rather than a
string.
Usually it's best not to use the `size` argument with this method, but
it's provided for compatibility.
"""
if not hasattr(self._file, 'read'):
raise EOFError
if not isinstance(dtype, np.dtype):
dtype = np.dtype(dtype)
if size and size % dtype.itemsize != 0:
raise ValueError('size %d not a multiple of %s' % (size, dtype))
if isinstance(shape, int):
shape = (shape, )
if not (size or shape):
warnings.warn('No size or shape given to readarray(); assuming a '
'shape of (1,)')
shape = (1, )
if size and not shape:
shape = (size // dtype.itemsize, )
if size and shape:
actualsize = np.prod(shape) * dtype.itemsize
if actualsize < size:
raise ValueError('size %d is too few bytes for a %s array of '
'%s' % (size, shape, dtype))
if actualsize < size:
raise ValueError('size %d is too many bytes for a %s array of '
'%s' % (size, shape, dtype))
if self.memmap:
if self._mmap is None:
# Instantiate Memmap array of the file offset at 0
# (so we can return slices of it to offset anywhere else into
# the file)
memmap = Memmap(self._file,
mode=MEMMAP_MODES[self.mode],
dtype=np.uint8)
# Now we immediately discard the memmap array; we are really
# just using it as a factory function to instantiate the mmap
# object in a convenient way (may later do away with this
# usage)
self._mmap = memmap.base
# Prevent dorking with self._memmap._mmap by memmap.__del__ in
# Numpy 1.6 (see
# https://github.com/numpy/numpy/commit/dcc355a0b179387eeba10c95baf2e1eb21d417c7)
memmap._mmap = None
del memmap
return np.ndarray(shape=shape,
dtype=dtype,
offset=offset,
buffer=self._mmap)
else:
count = reduce(lambda x, y: x * y, shape)
pos = self._file.tell()
self._file.seek(offset)
data = _array_from_file(self._file, dtype, count, '')
data.shape = shape
self._file.seek(pos)
return data