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850 lines
31 KiB
Python
850 lines
31 KiB
Python
6 years ago
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''' Classes for read / write of matlab (TM) 5 files
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The matfile specification last found here:
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https://www.mathworks.com/access/helpdesk/help/pdf_doc/matlab/matfile_format.pdf
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(as of December 5 2008)
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'''
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from __future__ import division, print_function, absolute_import
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'''
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=================================
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Note on functions and mat files
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=================================
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The document above does not give any hints as to the storage of matlab
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function handles, or anonymous function handles. I had therefore to
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guess the format of matlab arrays of ``mxFUNCTION_CLASS`` and
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``mxOPAQUE_CLASS`` by looking at example mat files.
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``mxFUNCTION_CLASS`` stores all types of matlab functions. It seems to
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contain a struct matrix with a set pattern of fields. For anonymous
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functions, a sub-fields of one of these fields seems to contain the
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well-named ``mxOPAQUE_CLASS``. This seems to contain:
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* array flags as for any matlab matrix
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* 3 int8 strings
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* a matrix
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It seems that, whenever the mat file contains a ``mxOPAQUE_CLASS``
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instance, there is also an un-named matrix (name == '') at the end of
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the mat file. I'll call this the ``__function_workspace__`` matrix.
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When I saved two anonymous functions in a mat file, or appended another
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anonymous function to the mat file, there was still only one
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``__function_workspace__`` un-named matrix at the end, but larger than
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that for a mat file with a single anonymous function, suggesting that
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the workspaces for the two functions had been merged.
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The ``__function_workspace__`` matrix appears to be of double class
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(``mxCLASS_DOUBLE``), but stored as uint8, the memory for which is in
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the format of a mini .mat file, without the first 124 bytes of the file
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header (the description and the subsystem_offset), but with the version
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U2 bytes, and the S2 endian test bytes. There follow 4 zero bytes,
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presumably for 8 byte padding, and then a series of ``miMATRIX``
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entries, as in a standard mat file. The ``miMATRIX`` entries appear to
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be series of un-named (name == '') matrices, and may also contain arrays
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of this same mini-mat format.
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I guess that:
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* saving an anonymous function back to a mat file will need the
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associated ``__function_workspace__`` matrix saved as well for the
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anonymous function to work correctly.
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* appending to a mat file that has a ``__function_workspace__`` would
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involve first pulling off this workspace, appending, checking whether
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there were any more anonymous functions appended, and then somehow
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merging the relevant workspaces, and saving at the end of the mat
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file.
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The mat files I was playing with are in ``tests/data``:
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* sqr.mat
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* parabola.mat
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* some_functions.mat
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See ``tests/test_mio.py:test_mio_funcs.py`` for a debugging
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script I was working with.
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'''
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# Small fragments of current code adapted from matfile.py by Heiko
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# Henkelmann
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import os
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import time
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import sys
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import zlib
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from io import BytesIO
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import warnings
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import numpy as np
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from numpy.compat import asbytes, asstr
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import scipy.sparse
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from scipy._lib.six import string_types
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from .byteordercodes import native_code, swapped_code
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from .miobase import (MatFileReader, docfiller, matdims, read_dtype,
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arr_to_chars, arr_dtype_number, MatWriteError,
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MatReadError, MatReadWarning)
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# Reader object for matlab 5 format variables
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from .mio5_utils import VarReader5
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# Constants and helper objects
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from .mio5_params import (MatlabObject, MatlabFunction, MDTYPES, NP_TO_MTYPES,
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NP_TO_MXTYPES, miCOMPRESSED, miMATRIX, miINT8,
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miUTF8, miUINT32, mxCELL_CLASS, mxSTRUCT_CLASS,
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mxOBJECT_CLASS, mxCHAR_CLASS, mxSPARSE_CLASS,
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mxDOUBLE_CLASS, mclass_info)
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from .streams import ZlibInputStream
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class MatFile5Reader(MatFileReader):
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''' Reader for Mat 5 mat files
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Adds the following attribute to base class
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uint16_codec - char codec to use for uint16 char arrays
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(defaults to system default codec)
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Uses variable reader that has the following stardard interface (see
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abstract class in ``miobase``::
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__init__(self, file_reader)
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read_header(self)
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array_from_header(self)
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and added interface::
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set_stream(self, stream)
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read_full_tag(self)
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'''
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@docfiller
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def __init__(self,
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mat_stream,
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byte_order=None,
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mat_dtype=False,
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squeeze_me=False,
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chars_as_strings=True,
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matlab_compatible=False,
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struct_as_record=True,
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verify_compressed_data_integrity=True,
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uint16_codec=None
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):
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'''Initializer for matlab 5 file format reader
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%(matstream_arg)s
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%(load_args)s
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%(struct_arg)s
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uint16_codec : {None, string}
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Set codec to use for uint16 char arrays (e.g. 'utf-8').
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Use system default codec if None
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'''
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super(MatFile5Reader, self).__init__(
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mat_stream,
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byte_order,
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mat_dtype,
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squeeze_me,
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chars_as_strings,
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matlab_compatible,
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struct_as_record,
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verify_compressed_data_integrity
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)
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# Set uint16 codec
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if not uint16_codec:
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uint16_codec = sys.getdefaultencoding()
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self.uint16_codec = uint16_codec
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# placeholders for readers - see initialize_read method
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self._file_reader = None
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self._matrix_reader = None
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def guess_byte_order(self):
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''' Guess byte order.
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Sets stream pointer to 0 '''
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self.mat_stream.seek(126)
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mi = self.mat_stream.read(2)
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self.mat_stream.seek(0)
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return mi == b'IM' and '<' or '>'
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def read_file_header(self):
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''' Read in mat 5 file header '''
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hdict = {}
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hdr_dtype = MDTYPES[self.byte_order]['dtypes']['file_header']
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hdr = read_dtype(self.mat_stream, hdr_dtype)
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hdict['__header__'] = hdr['description'].item().strip(b' \t\n\000')
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v_major = hdr['version'] >> 8
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v_minor = hdr['version'] & 0xFF
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hdict['__version__'] = '%d.%d' % (v_major, v_minor)
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return hdict
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def initialize_read(self):
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''' Run when beginning read of variables
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Sets up readers from parameters in `self`
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'''
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# reader for top level stream. We need this extra top-level
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# reader because we use the matrix_reader object to contain
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# compressed matrices (so they have their own stream)
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self._file_reader = VarReader5(self)
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# reader for matrix streams
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self._matrix_reader = VarReader5(self)
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def read_var_header(self):
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''' Read header, return header, next position
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Header has to define at least .name and .is_global
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Parameters
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----------
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None
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Returns
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-------
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header : object
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object that can be passed to self.read_var_array, and that
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has attributes .name and .is_global
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next_position : int
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position in stream of next variable
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'''
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mdtype, byte_count = self._file_reader.read_full_tag()
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if not byte_count > 0:
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raise ValueError("Did not read any bytes")
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next_pos = self.mat_stream.tell() + byte_count
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if mdtype == miCOMPRESSED:
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# Make new stream from compressed data
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stream = ZlibInputStream(self.mat_stream, byte_count)
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self._matrix_reader.set_stream(stream)
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check_stream_limit = self.verify_compressed_data_integrity
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mdtype, byte_count = self._matrix_reader.read_full_tag()
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else:
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check_stream_limit = False
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self._matrix_reader.set_stream(self.mat_stream)
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if not mdtype == miMATRIX:
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raise TypeError('Expecting miMATRIX type here, got %d' % mdtype)
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header = self._matrix_reader.read_header(check_stream_limit)
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return header, next_pos
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def read_var_array(self, header, process=True):
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''' Read array, given `header`
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Parameters
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----------
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header : header object
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object with fields defining variable header
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process : {True, False} bool, optional
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If True, apply recursive post-processing during loading of
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array.
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Returns
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-------
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arr : array
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array with post-processing applied or not according to
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`process`.
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'''
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return self._matrix_reader.array_from_header(header, process)
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def get_variables(self, variable_names=None):
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''' get variables from stream as dictionary
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variable_names - optional list of variable names to get
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If variable_names is None, then get all variables in file
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'''
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if isinstance(variable_names, string_types):
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variable_names = [variable_names]
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elif variable_names is not None:
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variable_names = list(variable_names)
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self.mat_stream.seek(0)
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# Here we pass all the parameters in self to the reading objects
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self.initialize_read()
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mdict = self.read_file_header()
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mdict['__globals__'] = []
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while not self.end_of_stream():
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hdr, next_position = self.read_var_header()
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name = asstr(hdr.name)
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if name in mdict:
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warnings.warn('Duplicate variable name "%s" in stream'
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' - replacing previous with new\n'
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'Consider mio5.varmats_from_mat to split '
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'file into single variable files' % name,
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MatReadWarning, stacklevel=2)
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if name == '':
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# can only be a matlab 7 function workspace
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name = '__function_workspace__'
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# We want to keep this raw because mat_dtype processing
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# will break the format (uint8 as mxDOUBLE_CLASS)
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process = False
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else:
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process = True
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if variable_names is not None and name not in variable_names:
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self.mat_stream.seek(next_position)
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continue
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try:
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res = self.read_var_array(hdr, process)
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except MatReadError as err:
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warnings.warn(
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'Unreadable variable "%s", because "%s"' %
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(name, err),
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Warning, stacklevel=2)
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res = "Read error: %s" % err
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self.mat_stream.seek(next_position)
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mdict[name] = res
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if hdr.is_global:
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mdict['__globals__'].append(name)
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if variable_names is not None:
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variable_names.remove(name)
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if len(variable_names) == 0:
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break
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return mdict
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def list_variables(self):
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''' list variables from stream '''
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self.mat_stream.seek(0)
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# Here we pass all the parameters in self to the reading objects
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self.initialize_read()
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self.read_file_header()
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vars = []
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while not self.end_of_stream():
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hdr, next_position = self.read_var_header()
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name = asstr(hdr.name)
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if name == '':
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# can only be a matlab 7 function workspace
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name = '__function_workspace__'
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shape = self._matrix_reader.shape_from_header(hdr)
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if hdr.is_logical:
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info = 'logical'
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else:
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info = mclass_info.get(hdr.mclass, 'unknown')
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vars.append((name, shape, info))
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self.mat_stream.seek(next_position)
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return vars
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def varmats_from_mat(file_obj):
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""" Pull variables out of mat 5 file as a sequence of mat file objects
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This can be useful with a difficult mat file, containing unreadable
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variables. This routine pulls the variables out in raw form and puts them,
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unread, back into a file stream for saving or reading. Another use is the
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pathological case where there is more than one variable of the same name in
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the file; this routine returns the duplicates, whereas the standard reader
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will overwrite duplicates in the returned dictionary.
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The file pointer in `file_obj` will be undefined. File pointers for the
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returned file-like objects are set at 0.
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Parameters
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----------
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file_obj : file-like
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file object containing mat file
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Returns
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-------
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named_mats : list
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list contains tuples of (name, BytesIO) where BytesIO is a file-like
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object containing mat file contents as for a single variable. The
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BytesIO contains a string with the original header and a single var. If
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``var_file_obj`` is an individual BytesIO instance, then save as a mat
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file with something like ``open('test.mat',
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'wb').write(var_file_obj.read())``
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Examples
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--------
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>>> import scipy.io
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BytesIO is from the ``io`` module in python 3, and is ``cStringIO`` for
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python < 3.
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>>> mat_fileobj = BytesIO()
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>>> scipy.io.savemat(mat_fileobj, {'b': np.arange(10), 'a': 'a string'})
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>>> varmats = varmats_from_mat(mat_fileobj)
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>>> sorted([name for name, str_obj in varmats])
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['a', 'b']
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"""
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rdr = MatFile5Reader(file_obj)
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|
|
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()
|
||
|
|
mdict = 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, string_types) 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.tostring(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.tostring is < 4, the element will be zero-padded as needed.
|
||
|
|
tag['data'] = arr.tostring(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.product(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 one-dimensional 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.tostring())
|
||
|
|
|
||
|
|
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.tostring())
|
||
|
|
self.file_stream.write(out_str)
|
||
|
|
else: # not compressing
|
||
|
|
self._matrix_writer.write_top(var, asbytes(name), is_global)
|