projektAI/venv/Lib/site-packages/scipy/io/matlab/mio5.py

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''' Classes for read / write of matlab (TM) 5 files
The matfile specification last found here:
https://www.mathworks.com/access/helpdesk/help/pdf_doc/matlab/matfile_format.pdf
(as of December 5 2008)
'''
'''
=================================
Note on functions and mat files
=================================
The document above does not give any hints as to the storage of matlab
function handles, or anonymous function handles. I had, therefore, to
guess the format of matlab arrays of ``mxFUNCTION_CLASS`` and
``mxOPAQUE_CLASS`` by looking at example mat files.
``mxFUNCTION_CLASS`` stores all types of matlab functions. It seems to
contain a struct matrix with a set pattern of fields. For anonymous
functions, a sub-fields of one of these fields seems to contain the
well-named ``mxOPAQUE_CLASS``. This seems to contain:
* array flags as for any matlab matrix
* 3 int8 strings
* a matrix
It seems that whenever the mat file contains a ``mxOPAQUE_CLASS``
instance, there is also an un-named matrix (name == '') at the end of
the mat file. I'll call this the ``__function_workspace__`` matrix.
When I saved two anonymous functions in a mat file, or appended another
anonymous function to the mat file, there was still only one
``__function_workspace__`` un-named matrix at the end, but larger than
that for a mat file with a single anonymous function, suggesting that
the workspaces for the two functions had been merged.
The ``__function_workspace__`` matrix appears to be of double class
(``mxCLASS_DOUBLE``), but stored as uint8, the memory for which is in
the format of a mini .mat file, without the first 124 bytes of the file
header (the description and the subsystem_offset), but with the version
U2 bytes, and the S2 endian test bytes. There follow 4 zero bytes,
presumably for 8 byte padding, and then a series of ``miMATRIX``
entries, as in a standard mat file. The ``miMATRIX`` entries appear to
be series of un-named (name == '') matrices, and may also contain arrays
of this same mini-mat format.
I guess that:
* saving an anonymous function back to a mat file will need the
associated ``__function_workspace__`` matrix saved as well for the
anonymous function to work correctly.
* appending to a mat file that has a ``__function_workspace__`` would
involve first pulling off this workspace, appending, checking whether
there were any more anonymous functions appended, and then somehow
merging the relevant workspaces, and saving at the end of the mat
file.
The mat files I was playing with are in ``tests/data``:
* sqr.mat
* parabola.mat
* some_functions.mat
See ``tests/test_mio.py:test_mio_funcs.py`` for the debugging
script I was working with.
'''
# Small fragments of current code adapted from matfile.py by Heiko
# Henkelmann; parts of the code for simplify_cells=True adapted from
# http://blog.nephics.com/2019/08/28/better-loadmat-for-scipy/.
import os
import time
import sys
import zlib
from io import BytesIO
import warnings
import numpy as np
from numpy.compat import asbytes, asstr
import scipy.sparse
from .byteordercodes import native_code, swapped_code
from .miobase import (MatFileReader, docfiller, matdims, read_dtype,
arr_to_chars, arr_dtype_number, MatWriteError,
MatReadError, MatReadWarning)
# Reader object for matlab 5 format variables
from .mio5_utils import VarReader5
# Constants and helper objects
from .mio5_params import (MatlabObject, MatlabFunction, MDTYPES, NP_TO_MTYPES,
NP_TO_MXTYPES, miCOMPRESSED, miMATRIX, miINT8,
miUTF8, miUINT32, mxCELL_CLASS, mxSTRUCT_CLASS,
mxOBJECT_CLASS, mxCHAR_CLASS, mxSPARSE_CLASS,
mxDOUBLE_CLASS, mclass_info, mat_struct)
from .streams import ZlibInputStream
def _has_struct(elem):
"""Determine if elem is an array and if first array item is a struct."""
return (isinstance(elem, np.ndarray) and (elem.size > 0) and
isinstance(elem[0], mat_struct))
def _inspect_cell_array(ndarray):
"""Construct lists from cell arrays (loaded as numpy ndarrays), recursing
into items if they contain mat_struct objects."""
elem_list = []
for sub_elem in ndarray:
if isinstance(sub_elem, mat_struct):
elem_list.append(_matstruct_to_dict(sub_elem))
elif _has_struct(sub_elem):
elem_list.append(_inspect_cell_array(sub_elem))
else:
elem_list.append(sub_elem)
return elem_list
def _matstruct_to_dict(matobj):
"""Construct nested dicts from mat_struct objects."""
d = {}
for f in matobj._fieldnames:
elem = matobj.__dict__[f]
if isinstance(elem, mat_struct):
d[f] = _matstruct_to_dict(elem)
elif _has_struct(elem):
d[f] = _inspect_cell_array(elem)
else:
d[f] = elem
return d
def _simplify_cells(d):
"""Convert mat objects in dict to nested dicts."""
for key in d:
if isinstance(d[key], mat_struct):
d[key] = _matstruct_to_dict(d[key])
elif _has_struct(d[key]):
d[key] = _inspect_cell_array(d[key])
return d
class MatFile5Reader(MatFileReader):
''' Reader for Mat 5 mat files
Adds the following attribute to base class
uint16_codec - char codec to use for uint16 char arrays
(defaults to system default codec)
Uses variable reader that has the following stardard interface (see
abstract class in ``miobase``::
__init__(self, file_reader)
read_header(self)
array_from_header(self)
and added interface::
set_stream(self, stream)
read_full_tag(self)
'''
@docfiller
def __init__(self,
mat_stream,
byte_order=None,
mat_dtype=False,
squeeze_me=False,
chars_as_strings=True,
matlab_compatible=False,
struct_as_record=True,
verify_compressed_data_integrity=True,
uint16_codec=None,
simplify_cells=False):
'''Initializer for matlab 5 file format reader
%(matstream_arg)s
%(load_args)s
%(struct_arg)s
uint16_codec : {None, string}
Set codec to use for uint16 char arrays (e.g., 'utf-8').
Use system default codec if None
'''
super(MatFile5Reader, self).__init__(
mat_stream,
byte_order,
mat_dtype,
squeeze_me,
chars_as_strings,
matlab_compatible,
struct_as_record,
verify_compressed_data_integrity,
simplify_cells)
# Set uint16 codec
if not uint16_codec:
uint16_codec = sys.getdefaultencoding()
self.uint16_codec = uint16_codec
# placeholders for readers - see initialize_read method
self._file_reader = None
self._matrix_reader = None
def guess_byte_order(self):
''' Guess byte order.
Sets stream pointer to 0 '''
self.mat_stream.seek(126)
mi = self.mat_stream.read(2)
self.mat_stream.seek(0)
return mi == b'IM' and '<' or '>'
def read_file_header(self):
''' Read in mat 5 file header '''
hdict = {}
hdr_dtype = MDTYPES[self.byte_order]['dtypes']['file_header']
hdr = read_dtype(self.mat_stream, hdr_dtype)
hdict['__header__'] = hdr['description'].item().strip(b' \t\n\000')
v_major = hdr['version'] >> 8
v_minor = hdr['version'] & 0xFF
hdict['__version__'] = '%d.%d' % (v_major, v_minor)
return hdict
def initialize_read(self):
''' Run when beginning read of variables
Sets up readers from parameters in `self`
'''
# reader for top level stream. We need this extra top-level
# reader because we use the matrix_reader object to contain
# compressed matrices (so they have their own stream)
self._file_reader = VarReader5(self)
# reader for matrix streams
self._matrix_reader = VarReader5(self)
def read_var_header(self):
''' Read header, return header, next position
Header has to define at least .name and .is_global
Parameters
----------
None
Returns
-------
header : object
object that can be passed to self.read_var_array, and that
has attributes .name and .is_global
next_position : int
position in stream of next variable
'''
mdtype, byte_count = self._file_reader.read_full_tag()
if not byte_count > 0:
raise ValueError("Did not read any bytes")
next_pos = self.mat_stream.tell() + byte_count
if mdtype == miCOMPRESSED:
# Make new stream from compressed data
stream = ZlibInputStream(self.mat_stream, byte_count)
self._matrix_reader.set_stream(stream)
check_stream_limit = self.verify_compressed_data_integrity
mdtype, byte_count = self._matrix_reader.read_full_tag()
else:
check_stream_limit = False
self._matrix_reader.set_stream(self.mat_stream)
if not mdtype == miMATRIX:
raise TypeError('Expecting miMATRIX type here, got %d' % mdtype)
header = self._matrix_reader.read_header(check_stream_limit)
return header, next_pos
def read_var_array(self, header, process=True):
''' Read array, given `header`
Parameters
----------
header : header object
object with fields defining variable header
process : {True, False} bool, optional
If True, apply recursive post-processing during loading of
array.
Returns
-------
arr : array
array with post-processing applied or not according to
`process`.
'''
return self._matrix_reader.array_from_header(header, process)
def get_variables(self, variable_names=None):
''' get variables from stream as dictionary
variable_names - optional list of variable names to get
If variable_names is None, then get all variables in file
'''
if isinstance(variable_names, str):
variable_names = [variable_names]
elif variable_names is not None:
variable_names = list(variable_names)
self.mat_stream.seek(0)
# Here we pass all the parameters in self to the reading objects
self.initialize_read()
mdict = self.read_file_header()
mdict['__globals__'] = []
while not self.end_of_stream():
hdr, next_position = self.read_var_header()
name = asstr(hdr.name)
if name in mdict:
warnings.warn('Duplicate variable name "%s" in stream'
' - replacing previous with new\n'
'Consider mio5.varmats_from_mat to split '
'file into single variable files' % name,
MatReadWarning, stacklevel=2)
if name == '':
# can only be a matlab 7 function workspace
name = '__function_workspace__'
# We want to keep this raw because mat_dtype processing
# will break the format (uint8 as mxDOUBLE_CLASS)
process = False
else:
process = True
if variable_names is not None and name not in variable_names:
self.mat_stream.seek(next_position)
continue
try:
res = self.read_var_array(hdr, process)
except MatReadError as err:
warnings.warn(
'Unreadable variable "%s", because "%s"' %
(name, err),
Warning, stacklevel=2)
res = "Read error: %s" % err
self.mat_stream.seek(next_position)
mdict[name] = res
if hdr.is_global:
mdict['__globals__'].append(name)
if variable_names is not None:
variable_names.remove(name)
if len(variable_names) == 0:
break
if self.simplify_cells:
return _simplify_cells(mdict)
else:
return mdict
def list_variables(self):
''' list variables from stream '''
self.mat_stream.seek(0)
# Here we pass all the parameters in self to the reading objects
self.initialize_read()
self.read_file_header()
vars = []
while not self.end_of_stream():
hdr, next_position = self.read_var_header()
name = asstr(hdr.name)
if name == '':
# can only be a matlab 7 function workspace
name = '__function_workspace__'
shape = self._matrix_reader.shape_from_header(hdr)
if hdr.is_logical:
info = 'logical'
else:
info = mclass_info.get(hdr.mclass, 'unknown')
vars.append((name, shape, info))
self.mat_stream.seek(next_position)
return vars
def varmats_from_mat(file_obj):
""" Pull variables out of mat 5 file as a sequence of mat file objects
This can be useful with a difficult mat file, containing unreadable
variables. This routine pulls the variables out in raw form and puts them,
unread, back into a file stream for saving or reading. Another use is the
pathological case where there is more than one variable of the same name in
the file; this routine returns the duplicates, whereas the standard reader
will overwrite duplicates in the returned dictionary.
The file pointer in `file_obj` will be undefined. File pointers for the
returned file-like objects are set at 0.
Parameters
----------
file_obj : file-like
file object containing mat file
Returns
-------
named_mats : list
list contains tuples of (name, BytesIO) where BytesIO is a file-like
object containing mat file contents as for a single variable. The
BytesIO contains a string with the original header and a single var. If
``var_file_obj`` is an individual BytesIO instance, then save as a mat
file with something like ``open('test.mat',
'wb').write(var_file_obj.read())``
Examples
--------
>>> import scipy.io
BytesIO is from the ``io`` module in Python 3, and is ``cStringIO`` for
Python < 3.
>>> mat_fileobj = BytesIO()
>>> scipy.io.savemat(mat_fileobj, {'b': np.arange(10), 'a': 'a string'})
>>> varmats = varmats_from_mat(mat_fileobj)
>>> sorted([name for name, str_obj in varmats])
['a', 'b']
"""
rdr = MatFile5Reader(file_obj)
file_obj.seek(0)
# Raw read of top-level file header
hdr_len = MDTYPES[native_code]['dtypes']['file_header'].itemsize
raw_hdr = file_obj.read(hdr_len)
# Initialize variable reading
file_obj.seek(0)
rdr.initialize_read()
rdr.read_file_header()
next_position = file_obj.tell()
named_mats = []
while not rdr.end_of_stream():
start_position = next_position
hdr, next_position = rdr.read_var_header()
name = asstr(hdr.name)
# Read raw variable string
file_obj.seek(start_position)
byte_count = next_position - start_position
var_str = file_obj.read(byte_count)
# write to stringio object
out_obj = BytesIO()
out_obj.write(raw_hdr)
out_obj.write(var_str)
out_obj.seek(0)
named_mats.append((name, out_obj))
return named_mats
class EmptyStructMarker(object):
""" Class to indicate presence of empty matlab struct on output """
def to_writeable(source):
''' Convert input object ``source`` to something we can write
Parameters
----------
source : object
Returns
-------
arr : None or ndarray or EmptyStructMarker
If `source` cannot be converted to something we can write to a matfile,
return None. If `source` is equivalent to an empty dictionary, return
``EmptyStructMarker``. Otherwise return `source` converted to an
ndarray with contents for writing to matfile.
'''
if isinstance(source, np.ndarray):
return source
if source is None:
return None
# Objects that implement mappings
is_mapping = (hasattr(source, 'keys') and hasattr(source, 'values') and
hasattr(source, 'items'))
# Objects that don't implement mappings, but do have dicts
if isinstance(source, np.generic):
# NumPy scalars are never mappings (PyPy issue workaround)
pass
elif not is_mapping and hasattr(source, '__dict__'):
source = dict((key, value) for key, value in source.__dict__.items()
if not key.startswith('_'))
is_mapping = True
if is_mapping:
dtype = []
values = []
for field, value in source.items():
if (isinstance(field, str) and
field[0] not in '_0123456789'):
dtype.append((str(field), object))
values.append(value)
if dtype:
return np.array([tuple(values)], dtype)
else:
return EmptyStructMarker
# Next try and convert to an array
narr = np.asanyarray(source)
if narr.dtype.type in (object, np.object_) and \
narr.shape == () and narr == source:
# No interesting conversion possible
return None
return narr
# Native byte ordered dtypes for convenience for writers
NDT_FILE_HDR = MDTYPES[native_code]['dtypes']['file_header']
NDT_TAG_FULL = MDTYPES[native_code]['dtypes']['tag_full']
NDT_TAG_SMALL = MDTYPES[native_code]['dtypes']['tag_smalldata']
NDT_ARRAY_FLAGS = MDTYPES[native_code]['dtypes']['array_flags']
class VarWriter5(object):
''' Generic matlab matrix writing class '''
mat_tag = np.zeros((), NDT_TAG_FULL)
mat_tag['mdtype'] = miMATRIX
def __init__(self, file_writer):
self.file_stream = file_writer.file_stream
self.unicode_strings = file_writer.unicode_strings
self.long_field_names = file_writer.long_field_names
self.oned_as = file_writer.oned_as
# These are used for top level writes, and unset after
self._var_name = None
self._var_is_global = False
def write_bytes(self, arr):
self.file_stream.write(arr.tobytes(order='F'))
def write_string(self, s):
self.file_stream.write(s)
def write_element(self, arr, mdtype=None):
''' write tag and data '''
if mdtype is None:
mdtype = NP_TO_MTYPES[arr.dtype.str[1:]]
# Array needs to be in native byte order
if arr.dtype.byteorder == swapped_code:
arr = arr.byteswap().newbyteorder()
byte_count = arr.size*arr.itemsize
if byte_count <= 4:
self.write_smalldata_element(arr, mdtype, byte_count)
else:
self.write_regular_element(arr, mdtype, byte_count)
def write_smalldata_element(self, arr, mdtype, byte_count):
# write tag with embedded data
tag = np.zeros((), NDT_TAG_SMALL)
tag['byte_count_mdtype'] = (byte_count << 16) + mdtype
# if arr.tobytes is < 4, the element will be zero-padded as needed.
tag['data'] = arr.tobytes(order='F')
self.write_bytes(tag)
def write_regular_element(self, arr, mdtype, byte_count):
# write tag, data
tag = np.zeros((), NDT_TAG_FULL)
tag['mdtype'] = mdtype
tag['byte_count'] = byte_count
self.write_bytes(tag)
self.write_bytes(arr)
# pad to next 64-bit boundary
bc_mod_8 = byte_count % 8
if bc_mod_8:
self.file_stream.write(b'\x00' * (8-bc_mod_8))
def write_header(self,
shape,
mclass,
is_complex=False,
is_logical=False,
nzmax=0):
''' Write header for given data options
shape : sequence
array shape
mclass - mat5 matrix class
is_complex - True if matrix is complex
is_logical - True if matrix is logical
nzmax - max non zero elements for sparse arrays
We get the name and the global flag from the object, and reset
them to defaults after we've used them
'''
# get name and is_global from one-shot object store
name = self._var_name
is_global = self._var_is_global
# initialize the top-level matrix tag, store position
self._mat_tag_pos = self.file_stream.tell()
self.write_bytes(self.mat_tag)
# write array flags (complex, global, logical, class, nzmax)
af = np.zeros((), NDT_ARRAY_FLAGS)
af['data_type'] = miUINT32
af['byte_count'] = 8
flags = is_complex << 3 | is_global << 2 | is_logical << 1
af['flags_class'] = mclass | flags << 8
af['nzmax'] = nzmax
self.write_bytes(af)
# shape
self.write_element(np.array(shape, dtype='i4'))
# write name
name = np.asarray(name)
if name == '': # empty string zero-terminated
self.write_smalldata_element(name, miINT8, 0)
else:
self.write_element(name, miINT8)
# reset the one-shot store to defaults
self._var_name = ''
self._var_is_global = False
def update_matrix_tag(self, start_pos):
curr_pos = self.file_stream.tell()
self.file_stream.seek(start_pos)
byte_count = curr_pos - start_pos - 8
if byte_count >= 2**32:
raise MatWriteError("Matrix too large to save with Matlab "
"5 format")
self.mat_tag['byte_count'] = byte_count
self.write_bytes(self.mat_tag)
self.file_stream.seek(curr_pos)
def write_top(self, arr, name, is_global):
""" Write variable at top level of mat file
Parameters
----------
arr : array_like
array-like object to create writer for
name : str, optional
name as it will appear in matlab workspace
default is empty string
is_global : {False, True}, optional
whether variable will be global on load into matlab
"""
# these are set before the top-level header write, and unset at
# the end of the same write, because they do not apply for lower levels
self._var_is_global = is_global
self._var_name = name
# write the header and data
self.write(arr)
def write(self, arr):
''' Write `arr` to stream at top and sub levels
Parameters
----------
arr : array_like
array-like object to create writer for
'''
# store position, so we can update the matrix tag
mat_tag_pos = self.file_stream.tell()
# First check if these are sparse
if scipy.sparse.issparse(arr):
self.write_sparse(arr)
self.update_matrix_tag(mat_tag_pos)
return
# Try to convert things that aren't arrays
narr = to_writeable(arr)
if narr is None:
raise TypeError('Could not convert %s (type %s) to array'
% (arr, type(arr)))
if isinstance(narr, MatlabObject):
self.write_object(narr)
elif isinstance(narr, MatlabFunction):
raise MatWriteError('Cannot write matlab functions')
elif narr is EmptyStructMarker: # empty struct array
self.write_empty_struct()
elif narr.dtype.fields: # struct array
self.write_struct(narr)
elif narr.dtype.hasobject: # cell array
self.write_cells(narr)
elif narr.dtype.kind in ('U', 'S'):
if self.unicode_strings:
codec = 'UTF8'
else:
codec = 'ascii'
self.write_char(narr, codec)
else:
self.write_numeric(narr)
self.update_matrix_tag(mat_tag_pos)
def write_numeric(self, arr):
imagf = arr.dtype.kind == 'c'
logif = arr.dtype.kind == 'b'
try:
mclass = NP_TO_MXTYPES[arr.dtype.str[1:]]
except KeyError:
# No matching matlab type, probably complex256 / float128 / float96
# Cast data to complex128 / float64.
if imagf:
arr = arr.astype('c128')
elif logif:
arr = arr.astype('i1') # Should only contain 0/1
else:
arr = arr.astype('f8')
mclass = mxDOUBLE_CLASS
self.write_header(matdims(arr, self.oned_as),
mclass,
is_complex=imagf,
is_logical=logif)
if imagf:
self.write_element(arr.real)
self.write_element(arr.imag)
else:
self.write_element(arr)
def write_char(self, arr, codec='ascii'):
''' Write string array `arr` with given `codec`
'''
if arr.size == 0 or np.all(arr == ''):
# This an empty string array or a string array containing
# only empty strings. Matlab cannot distinguish between a
# string array that is empty, and a string array containing
# only empty strings, because it stores strings as arrays of
# char. There is no way of having an array of char that is
# not empty, but contains an empty string. We have to
# special-case the array-with-empty-strings because even
# empty strings have zero padding, which would otherwise
# appear in matlab as a string with a space.
shape = (0,) * np.max([arr.ndim, 2])
self.write_header(shape, mxCHAR_CLASS)
self.write_smalldata_element(arr, miUTF8, 0)
return
# non-empty string.
#
# Convert to char array
arr = arr_to_chars(arr)
# We have to write the shape directly, because we are going
# recode the characters, and the resulting stream of chars
# may have a different length
shape = arr.shape
self.write_header(shape, mxCHAR_CLASS)
if arr.dtype.kind == 'U' and arr.size:
# Make one long string from all the characters. We need to
# transpose here, because we're flattening the array, before
# we write the bytes. The bytes have to be written in
# Fortran order.
n_chars = np.prod(shape)
st_arr = np.ndarray(shape=(),
dtype=arr_dtype_number(arr, n_chars),
buffer=arr.T.copy()) # Fortran order
# Recode with codec to give byte string
st = st_arr.item().encode(codec)
# Reconstruct as 1-D byte array
arr = np.ndarray(shape=(len(st),),
dtype='S1',
buffer=st)
self.write_element(arr, mdtype=miUTF8)
def write_sparse(self, arr):
''' Sparse matrices are 2D
'''
A = arr.tocsc() # convert to sparse CSC format
A.sort_indices() # MATLAB expects sorted row indices
is_complex = (A.dtype.kind == 'c')
is_logical = (A.dtype.kind == 'b')
nz = A.nnz
self.write_header(matdims(arr, self.oned_as),
mxSPARSE_CLASS,
is_complex=is_complex,
is_logical=is_logical,
# matlab won't load file with 0 nzmax
nzmax=1 if nz == 0 else nz)
self.write_element(A.indices.astype('i4'))
self.write_element(A.indptr.astype('i4'))
self.write_element(A.data.real)
if is_complex:
self.write_element(A.data.imag)
def write_cells(self, arr):
self.write_header(matdims(arr, self.oned_as),
mxCELL_CLASS)
# loop over data, column major
A = np.atleast_2d(arr).flatten('F')
for el in A:
self.write(el)
def write_empty_struct(self):
self.write_header((1, 1), mxSTRUCT_CLASS)
# max field name length set to 1 in an example matlab struct
self.write_element(np.array(1, dtype=np.int32))
# Field names element is empty
self.write_element(np.array([], dtype=np.int8))
def write_struct(self, arr):
self.write_header(matdims(arr, self.oned_as),
mxSTRUCT_CLASS)
self._write_items(arr)
def _write_items(self, arr):
# write fieldnames
fieldnames = [f[0] for f in arr.dtype.descr]
length = max([len(fieldname) for fieldname in fieldnames])+1
max_length = (self.long_field_names and 64) or 32
if length > max_length:
raise ValueError("Field names are restricted to %d characters" %
(max_length-1))
self.write_element(np.array([length], dtype='i4'))
self.write_element(
np.array(fieldnames, dtype='S%d' % (length)),
mdtype=miINT8)
A = np.atleast_2d(arr).flatten('F')
for el in A:
for f in fieldnames:
self.write(el[f])
def write_object(self, arr):
'''Same as writing structs, except different mx class, and extra
classname element after header
'''
self.write_header(matdims(arr, self.oned_as),
mxOBJECT_CLASS)
self.write_element(np.array(arr.classname, dtype='S'),
mdtype=miINT8)
self._write_items(arr)
class MatFile5Writer(object):
''' Class for writing mat5 files '''
@docfiller
def __init__(self, file_stream,
do_compression=False,
unicode_strings=False,
global_vars=None,
long_field_names=False,
oned_as='row'):
''' Initialize writer for matlab 5 format files
Parameters
----------
%(do_compression)s
%(unicode_strings)s
global_vars : None or sequence of strings, optional
Names of variables to be marked as global for matlab
%(long_fields)s
%(oned_as)s
'''
self.file_stream = file_stream
self.do_compression = do_compression
self.unicode_strings = unicode_strings
if global_vars:
self.global_vars = global_vars
else:
self.global_vars = []
self.long_field_names = long_field_names
self.oned_as = oned_as
self._matrix_writer = None
def write_file_header(self):
# write header
hdr = np.zeros((), NDT_FILE_HDR)
hdr['description'] = 'MATLAB 5.0 MAT-file Platform: %s, Created on: %s' \
% (os.name,time.asctime())
hdr['version'] = 0x0100
hdr['endian_test'] = np.ndarray(shape=(),
dtype='S2',
buffer=np.uint16(0x4d49))
self.file_stream.write(hdr.tobytes())
def put_variables(self, mdict, write_header=None):
''' Write variables in `mdict` to stream
Parameters
----------
mdict : mapping
mapping with method ``items`` returns name, contents pairs where
``name`` which will appear in the matlab workspace in file load, and
``contents`` is something writeable to a matlab file, such as a NumPy
array.
write_header : {None, True, False}, optional
If True, then write the matlab file header before writing the
variables. If None (the default) then write the file header
if we are at position 0 in the stream. By setting False
here, and setting the stream position to the end of the file,
you can append variables to a matlab file
'''
# write header if requested, or None and start of file
if write_header is None:
write_header = self.file_stream.tell() == 0
if write_header:
self.write_file_header()
self._matrix_writer = VarWriter5(self)
for name, var in mdict.items():
if name[0] == '_':
continue
is_global = name in self.global_vars
if self.do_compression:
stream = BytesIO()
self._matrix_writer.file_stream = stream
self._matrix_writer.write_top(var, asbytes(name), is_global)
out_str = zlib.compress(stream.getvalue())
tag = np.empty((), NDT_TAG_FULL)
tag['mdtype'] = miCOMPRESSED
tag['byte_count'] = len(out_str)
self.file_stream.write(tag.tobytes())
self.file_stream.write(out_str)
else: # not compressing
self._matrix_writer.write_top(var, asbytes(name), is_global)