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diff --git a/.venv/lib/python3.12/site-packages/numpy/lib/_format_impl.py b/.venv/lib/python3.12/site-packages/numpy/lib/_format_impl.py new file mode 100644 index 0000000..7378ba5 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/numpy/lib/_format_impl.py @@ -0,0 +1,1036 @@ +""" +Binary serialization + +NPY format +========== + +A simple format for saving numpy arrays to disk with the full +information about them. + +The ``.npy`` format is the standard binary file format in NumPy for +persisting a *single* arbitrary NumPy array on disk. The format stores all +of the shape and dtype information necessary to reconstruct the array +correctly even on another machine with a different architecture. +The format is designed to be as simple as possible while achieving +its limited goals. + +The ``.npz`` format is the standard format for persisting *multiple* NumPy +arrays on disk. A ``.npz`` file is a zip file containing multiple ``.npy`` +files, one for each array. + +Capabilities +------------ + +- Can represent all NumPy arrays including nested record arrays and + object arrays. + +- Represents the data in its native binary form. + +- Supports Fortran-contiguous arrays directly. + +- Stores all of the necessary information to reconstruct the array + including shape and dtype on a machine of a different + architecture. Both little-endian and big-endian arrays are + supported, and a file with little-endian numbers will yield + a little-endian array on any machine reading the file. The + types are described in terms of their actual sizes. For example, + if a machine with a 64-bit C "long int" writes out an array with + "long ints", a reading machine with 32-bit C "long ints" will yield + an array with 64-bit integers. + +- Is straightforward to reverse engineer. Datasets often live longer than + the programs that created them. A competent developer should be + able to create a solution in their preferred programming language to + read most ``.npy`` files that they have been given without much + documentation. + +- Allows memory-mapping of the data. See `open_memmap`. + +- Can be read from a filelike stream object instead of an actual file. + +- Stores object arrays, i.e. arrays containing elements that are arbitrary + Python objects. Files with object arrays are not to be mmapable, but + can be read and written to disk. + +Limitations +----------- + +- Arbitrary subclasses of numpy.ndarray are not completely preserved. + Subclasses will be accepted for writing, but only the array data will + be written out. A regular numpy.ndarray object will be created + upon reading the file. + +.. warning:: + + Due to limitations in the interpretation of structured dtypes, dtypes + with fields with empty names will have the names replaced by 'f0', 'f1', + etc. Such arrays will not round-trip through the format entirely + accurately. The data is intact; only the field names will differ. We are + working on a fix for this. This fix will not require a change in the + file format. The arrays with such structures can still be saved and + restored, and the correct dtype may be restored by using the + ``loadedarray.view(correct_dtype)`` method. + +File extensions +--------------- + +We recommend using the ``.npy`` and ``.npz`` extensions for files saved +in this format. This is by no means a requirement; applications may wish +to use these file formats but use an extension specific to the +application. In the absence of an obvious alternative, however, +we suggest using ``.npy`` and ``.npz``. + +Version numbering +----------------- + +The version numbering of these formats is independent of NumPy version +numbering. If the format is upgraded, the code in `numpy.io` will still +be able to read and write Version 1.0 files. + +Format Version 1.0 +------------------ + +The first 6 bytes are a magic string: exactly ``\\x93NUMPY``. + +The next 1 byte is an unsigned byte: the major version number of the file +format, e.g. ``\\x01``. + +The next 1 byte is an unsigned byte: the minor version number of the file +format, e.g. ``\\x00``. Note: the version of the file format is not tied +to the version of the numpy package. + +The next 2 bytes form a little-endian unsigned short int: the length of +the header data HEADER_LEN. + +The next HEADER_LEN bytes form the header data describing the array's +format. It is an ASCII string which contains a Python literal expression +of a dictionary. It is terminated by a newline (``\\n``) and padded with +spaces (``\\x20``) to make the total of +``len(magic string) + 2 + len(length) + HEADER_LEN`` be evenly divisible +by 64 for alignment purposes. + +The dictionary contains three keys: + + "descr" : dtype.descr + An object that can be passed as an argument to the `numpy.dtype` + constructor to create the array's dtype. + "fortran_order" : bool + Whether the array data is Fortran-contiguous or not. Since + Fortran-contiguous arrays are a common form of non-C-contiguity, + we allow them to be written directly to disk for efficiency. + "shape" : tuple of int + The shape of the array. + +For repeatability and readability, the dictionary keys are sorted in +alphabetic order. This is for convenience only. A writer SHOULD implement +this if possible. A reader MUST NOT depend on this. + +Following the header comes the array data. If the dtype contains Python +objects (i.e. ``dtype.hasobject is True``), then the data is a Python +pickle of the array. Otherwise the data is the contiguous (either C- +or Fortran-, depending on ``fortran_order``) bytes of the array. +Consumers can figure out the number of bytes by multiplying the number +of elements given by the shape (noting that ``shape=()`` means there is +1 element) by ``dtype.itemsize``. + +Format Version 2.0 +------------------ + +The version 1.0 format only allowed the array header to have a total size of +65535 bytes. This can be exceeded by structured arrays with a large number of +columns. The version 2.0 format extends the header size to 4 GiB. +`numpy.save` will automatically save in 2.0 format if the data requires it, +else it will always use the more compatible 1.0 format. + +The description of the fourth element of the header therefore has become: +"The next 4 bytes form a little-endian unsigned int: the length of the header +data HEADER_LEN." + +Format Version 3.0 +------------------ + +This version replaces the ASCII string (which in practice was latin1) with +a utf8-encoded string, so supports structured types with any unicode field +names. + +Notes +----- +The ``.npy`` format, including motivation for creating it and a comparison of +alternatives, is described in the +:doc:`"npy-format" NEP <neps:nep-0001-npy-format>`, however details have +evolved with time and this document is more current. + +""" +import io +import os +import pickle +import warnings + +import numpy +from numpy._utils import set_module +from numpy.lib._utils_impl import drop_metadata + +__all__ = [] + +drop_metadata.__module__ = "numpy.lib.format" + +EXPECTED_KEYS = {'descr', 'fortran_order', 'shape'} +MAGIC_PREFIX = b'\x93NUMPY' +MAGIC_LEN = len(MAGIC_PREFIX) + 2 +ARRAY_ALIGN = 64 # plausible values are powers of 2 between 16 and 4096 +BUFFER_SIZE = 2**18 # size of buffer for reading npz files in bytes +# allow growth within the address space of a 64 bit machine along one axis +GROWTH_AXIS_MAX_DIGITS = 21 # = len(str(8*2**64-1)) hypothetical int1 dtype + +# difference between version 1.0 and 2.0 is a 4 byte (I) header length +# instead of 2 bytes (H) allowing storage of large structured arrays +_header_size_info = { + (1, 0): ('<H', 'latin1'), + (2, 0): ('<I', 'latin1'), + (3, 0): ('<I', 'utf8'), +} + +# Python's literal_eval is not actually safe for large inputs, since parsing +# may become slow or even cause interpreter crashes. +# This is an arbitrary, low limit which should make it safe in practice. +_MAX_HEADER_SIZE = 10000 + + +def _check_version(version): + if version not in [(1, 0), (2, 0), (3, 0), None]: + msg = "we only support format version (1,0), (2,0), and (3,0), not %s" + raise ValueError(msg % (version,)) + + +@set_module("numpy.lib.format") +def magic(major, minor): + """ Return the magic string for the given file format version. + + Parameters + ---------- + major : int in [0, 255] + minor : int in [0, 255] + + Returns + ------- + magic : str + + Raises + ------ + ValueError if the version cannot be formatted. + """ + if major < 0 or major > 255: + raise ValueError("major version must be 0 <= major < 256") + if minor < 0 or minor > 255: + raise ValueError("minor version must be 0 <= minor < 256") + return MAGIC_PREFIX + bytes([major, minor]) + + +@set_module("numpy.lib.format") +def read_magic(fp): + """ Read the magic string to get the version of the file format. + + Parameters + ---------- + fp : filelike object + + Returns + ------- + major : int + minor : int + """ + magic_str = _read_bytes(fp, MAGIC_LEN, "magic string") + if magic_str[:-2] != MAGIC_PREFIX: + msg = "the magic string is not correct; expected %r, got %r" + raise ValueError(msg % (MAGIC_PREFIX, magic_str[:-2])) + major, minor = magic_str[-2:] + return major, minor + + +@set_module("numpy.lib.format") +def dtype_to_descr(dtype): + """ + Get a serializable descriptor from the dtype. + + The .descr attribute of a dtype object cannot be round-tripped through + the dtype() constructor. Simple types, like dtype('float32'), have + a descr which looks like a record array with one field with '' as + a name. The dtype() constructor interprets this as a request to give + a default name. Instead, we construct descriptor that can be passed to + dtype(). + + Parameters + ---------- + dtype : dtype + The dtype of the array that will be written to disk. + + Returns + ------- + descr : object + An object that can be passed to `numpy.dtype()` in order to + replicate the input dtype. + + """ + # NOTE: that drop_metadata may not return the right dtype e.g. for user + # dtypes. In that case our code below would fail the same, though. + new_dtype = drop_metadata(dtype) + if new_dtype is not dtype: + warnings.warn("metadata on a dtype is not saved to an npy/npz. " + "Use another format (such as pickle) to store it.", + UserWarning, stacklevel=2) + dtype = new_dtype + + if dtype.names is not None: + # This is a record array. The .descr is fine. XXX: parts of the + # record array with an empty name, like padding bytes, still get + # fiddled with. This needs to be fixed in the C implementation of + # dtype(). + return dtype.descr + elif not type(dtype)._legacy: + # this must be a user-defined dtype since numpy does not yet expose any + # non-legacy dtypes in the public API + # + # non-legacy dtypes don't yet have __array_interface__ + # support. Instead, as a hack, we use pickle to save the array, and lie + # that the dtype is object. When the array is loaded, the descriptor is + # unpickled with the array and the object dtype in the header is + # discarded. + # + # a future NEP should define a way to serialize user-defined + # descriptors and ideally work out the possible security implications + warnings.warn("Custom dtypes are saved as python objects using the " + "pickle protocol. Loading this file requires " + "allow_pickle=True to be set.", + UserWarning, stacklevel=2) + return "|O" + else: + return dtype.str + + +@set_module("numpy.lib.format") +def descr_to_dtype(descr): + """ + Returns a dtype based off the given description. + + This is essentially the reverse of `~lib.format.dtype_to_descr`. It will + remove the valueless padding fields created by, i.e. simple fields like + dtype('float32'), and then convert the description to its corresponding + dtype. + + Parameters + ---------- + descr : object + The object retrieved by dtype.descr. Can be passed to + `numpy.dtype` in order to replicate the input dtype. + + Returns + ------- + dtype : dtype + The dtype constructed by the description. + + """ + if isinstance(descr, str): + # No padding removal needed + return numpy.dtype(descr) + elif isinstance(descr, tuple): + # subtype, will always have a shape descr[1] + dt = descr_to_dtype(descr[0]) + return numpy.dtype((dt, descr[1])) + + titles = [] + names = [] + formats = [] + offsets = [] + offset = 0 + for field in descr: + if len(field) == 2: + name, descr_str = field + dt = descr_to_dtype(descr_str) + else: + name, descr_str, shape = field + dt = numpy.dtype((descr_to_dtype(descr_str), shape)) + + # Ignore padding bytes, which will be void bytes with '' as name + # Once support for blank names is removed, only "if name == ''" needed) + is_pad = (name == '' and dt.type is numpy.void and dt.names is None) + if not is_pad: + title, name = name if isinstance(name, tuple) else (None, name) + titles.append(title) + names.append(name) + formats.append(dt) + offsets.append(offset) + offset += dt.itemsize + + return numpy.dtype({'names': names, 'formats': formats, 'titles': titles, + 'offsets': offsets, 'itemsize': offset}) + + +@set_module("numpy.lib.format") +def header_data_from_array_1_0(array): + """ Get the dictionary of header metadata from a numpy.ndarray. + + Parameters + ---------- + array : numpy.ndarray + + Returns + ------- + d : dict + This has the appropriate entries for writing its string representation + to the header of the file. + """ + d = {'shape': array.shape} + if array.flags.c_contiguous: + d['fortran_order'] = False + elif array.flags.f_contiguous: + d['fortran_order'] = True + else: + # Totally non-contiguous data. We will have to make it C-contiguous + # before writing. Note that we need to test for C_CONTIGUOUS first + # because a 1-D array is both C_CONTIGUOUS and F_CONTIGUOUS. + d['fortran_order'] = False + + d['descr'] = dtype_to_descr(array.dtype) + return d + + +def _wrap_header(header, version): + """ + Takes a stringified header, and attaches the prefix and padding to it + """ + import struct + assert version is not None + fmt, encoding = _header_size_info[version] + header = header.encode(encoding) + hlen = len(header) + 1 + padlen = ARRAY_ALIGN - ((MAGIC_LEN + struct.calcsize(fmt) + hlen) % ARRAY_ALIGN) + try: + header_prefix = magic(*version) + struct.pack(fmt, hlen + padlen) + except struct.error: + msg = f"Header length {hlen} too big for version={version}" + raise ValueError(msg) from None + + # Pad the header with spaces and a final newline such that the magic + # string, the header-length short and the header are aligned on a + # ARRAY_ALIGN byte boundary. This supports memory mapping of dtypes + # aligned up to ARRAY_ALIGN on systems like Linux where mmap() + # offset must be page-aligned (i.e. the beginning of the file). + return header_prefix + header + b' ' * padlen + b'\n' + + +def _wrap_header_guess_version(header): + """ + Like `_wrap_header`, but chooses an appropriate version given the contents + """ + try: + return _wrap_header(header, (1, 0)) + except ValueError: + pass + + try: + ret = _wrap_header(header, (2, 0)) + except UnicodeEncodeError: + pass + else: + warnings.warn("Stored array in format 2.0. It can only be" + "read by NumPy >= 1.9", UserWarning, stacklevel=2) + return ret + + header = _wrap_header(header, (3, 0)) + warnings.warn("Stored array in format 3.0. It can only be " + "read by NumPy >= 1.17", UserWarning, stacklevel=2) + return header + + +def _write_array_header(fp, d, version=None): + """ Write the header for an array and returns the version used + + Parameters + ---------- + fp : filelike object + d : dict + This has the appropriate entries for writing its string representation + to the header of the file. + version : tuple or None + None means use oldest that works. Providing an explicit version will + raise a ValueError if the format does not allow saving this data. + Default: None + """ + header = ["{"] + for key, value in sorted(d.items()): + # Need to use repr here, since we eval these when reading + header.append(f"'{key}': {repr(value)}, ") + header.append("}") + header = "".join(header) + + # Add some spare space so that the array header can be modified in-place + # when changing the array size, e.g. when growing it by appending data at + # the end. + shape = d['shape'] + header += " " * ((GROWTH_AXIS_MAX_DIGITS - len(repr( + shape[-1 if d['fortran_order'] else 0] + ))) if len(shape) > 0 else 0) + + if version is None: + header = _wrap_header_guess_version(header) + else: + header = _wrap_header(header, version) + fp.write(header) + + +@set_module("numpy.lib.format") +def write_array_header_1_0(fp, d): + """ Write the header for an array using the 1.0 format. + + Parameters + ---------- + fp : filelike object + d : dict + This has the appropriate entries for writing its string + representation to the header of the file. + """ + _write_array_header(fp, d, (1, 0)) + + +@set_module("numpy.lib.format") +def write_array_header_2_0(fp, d): + """ Write the header for an array using the 2.0 format. + The 2.0 format allows storing very large structured arrays. + + Parameters + ---------- + fp : filelike object + d : dict + This has the appropriate entries for writing its string + representation to the header of the file. + """ + _write_array_header(fp, d, (2, 0)) + + +@set_module("numpy.lib.format") +def read_array_header_1_0(fp, max_header_size=_MAX_HEADER_SIZE): + """ + Read an array header from a filelike object using the 1.0 file format + version. + + This will leave the file object located just after the header. + + Parameters + ---------- + fp : filelike object + A file object or something with a `.read()` method like a file. + + Returns + ------- + shape : tuple of int + The shape of the array. + fortran_order : bool + The array data will be written out directly if it is either + C-contiguous or Fortran-contiguous. Otherwise, it will be made + contiguous before writing it out. + dtype : dtype + The dtype of the file's data. + max_header_size : int, optional + Maximum allowed size of the header. Large headers may not be safe + to load securely and thus require explicitly passing a larger value. + See :py:func:`ast.literal_eval()` for details. + + Raises + ------ + ValueError + If the data is invalid. + + """ + return _read_array_header( + fp, version=(1, 0), max_header_size=max_header_size) + + +@set_module("numpy.lib.format") +def read_array_header_2_0(fp, max_header_size=_MAX_HEADER_SIZE): + """ + Read an array header from a filelike object using the 2.0 file format + version. + + This will leave the file object located just after the header. + + Parameters + ---------- + fp : filelike object + A file object or something with a `.read()` method like a file. + max_header_size : int, optional + Maximum allowed size of the header. Large headers may not be safe + to load securely and thus require explicitly passing a larger value. + See :py:func:`ast.literal_eval()` for details. + + Returns + ------- + shape : tuple of int + The shape of the array. + fortran_order : bool + The array data will be written out directly if it is either + C-contiguous or Fortran-contiguous. Otherwise, it will be made + contiguous before writing it out. + dtype : dtype + The dtype of the file's data. + + Raises + ------ + ValueError + If the data is invalid. + + """ + return _read_array_header( + fp, version=(2, 0), max_header_size=max_header_size) + + +def _filter_header(s): + """Clean up 'L' in npz header ints. + + Cleans up the 'L' in strings representing integers. Needed to allow npz + headers produced in Python2 to be read in Python3. + + Parameters + ---------- + s : string + Npy file header. + + Returns + ------- + header : str + Cleaned up header. + + """ + import tokenize + from io import StringIO + + tokens = [] + last_token_was_number = False + for token in tokenize.generate_tokens(StringIO(s).readline): + token_type = token[0] + token_string = token[1] + if (last_token_was_number and + token_type == tokenize.NAME and + token_string == "L"): + continue + else: + tokens.append(token) + last_token_was_number = (token_type == tokenize.NUMBER) + return tokenize.untokenize(tokens) + + +def _read_array_header(fp, version, max_header_size=_MAX_HEADER_SIZE): + """ + see read_array_header_1_0 + """ + # Read an unsigned, little-endian short int which has the length of the + # header. + import ast + import struct + hinfo = _header_size_info.get(version) + if hinfo is None: + raise ValueError(f"Invalid version {version!r}") + hlength_type, encoding = hinfo + + hlength_str = _read_bytes(fp, struct.calcsize(hlength_type), "array header length") + header_length = struct.unpack(hlength_type, hlength_str)[0] + header = _read_bytes(fp, header_length, "array header") + header = header.decode(encoding) + if len(header) > max_header_size: + raise ValueError( + f"Header info length ({len(header)}) is large and may not be safe " + "to load securely.\n" + "To allow loading, adjust `max_header_size` or fully trust " + "the `.npy` file using `allow_pickle=True`.\n" + "For safety against large resource use or crashes, sandboxing " + "may be necessary.") + + # The header is a pretty-printed string representation of a literal + # Python dictionary with trailing newlines padded to a ARRAY_ALIGN byte + # boundary. The keys are strings. + # "shape" : tuple of int + # "fortran_order" : bool + # "descr" : dtype.descr + # Versions (2, 0) and (1, 0) could have been created by a Python 2 + # implementation before header filtering was implemented. + # + # For performance reasons, we try without _filter_header first though + try: + d = ast.literal_eval(header) + except SyntaxError as e: + if version <= (2, 0): + header = _filter_header(header) + try: + d = ast.literal_eval(header) + except SyntaxError as e2: + msg = "Cannot parse header: {!r}" + raise ValueError(msg.format(header)) from e2 + else: + warnings.warn( + "Reading `.npy` or `.npz` file required additional " + "header parsing as it was created on Python 2. Save the " + "file again to speed up loading and avoid this warning.", + UserWarning, stacklevel=4) + else: + msg = "Cannot parse header: {!r}" + raise ValueError(msg.format(header)) from e + if not isinstance(d, dict): + msg = "Header is not a dictionary: {!r}" + raise ValueError(msg.format(d)) + + if EXPECTED_KEYS != d.keys(): + keys = sorted(d.keys()) + msg = "Header does not contain the correct keys: {!r}" + raise ValueError(msg.format(keys)) + + # Sanity-check the values. + if (not isinstance(d['shape'], tuple) or + not all(isinstance(x, int) for x in d['shape'])): + msg = "shape is not valid: {!r}" + raise ValueError(msg.format(d['shape'])) + if not isinstance(d['fortran_order'], bool): + msg = "fortran_order is not a valid bool: {!r}" + raise ValueError(msg.format(d['fortran_order'])) + try: + dtype = descr_to_dtype(d['descr']) + except TypeError as e: + msg = "descr is not a valid dtype descriptor: {!r}" + raise ValueError(msg.format(d['descr'])) from e + + return d['shape'], d['fortran_order'], dtype + + +@set_module("numpy.lib.format") +def write_array(fp, array, version=None, allow_pickle=True, pickle_kwargs=None): + """ + Write an array to an NPY file, including a header. + + If the array is neither C-contiguous nor Fortran-contiguous AND the + file_like object is not a real file object, this function will have to + copy data in memory. + + Parameters + ---------- + fp : file_like object + An open, writable file object, or similar object with a + ``.write()`` method. + array : ndarray + The array to write to disk. + version : (int, int) or None, optional + The version number of the format. None means use the oldest + supported version that is able to store the data. Default: None + allow_pickle : bool, optional + Whether to allow writing pickled data. Default: True + pickle_kwargs : dict, optional + Additional keyword arguments to pass to pickle.dump, excluding + 'protocol'. These are only useful when pickling objects in object + arrays to Python 2 compatible format. + + Raises + ------ + ValueError + If the array cannot be persisted. This includes the case of + allow_pickle=False and array being an object array. + Various other errors + If the array contains Python objects as part of its dtype, the + process of pickling them may raise various errors if the objects + are not picklable. + + """ + _check_version(version) + _write_array_header(fp, header_data_from_array_1_0(array), version) + + if array.itemsize == 0: + buffersize = 0 + else: + # Set buffer size to 16 MiB to hide the Python loop overhead. + buffersize = max(16 * 1024 ** 2 // array.itemsize, 1) + + dtype_class = type(array.dtype) + + if array.dtype.hasobject or not dtype_class._legacy: + # We contain Python objects so we cannot write out the data + # directly. Instead, we will pickle it out + if not allow_pickle: + if array.dtype.hasobject: + raise ValueError("Object arrays cannot be saved when " + "allow_pickle=False") + if not dtype_class._legacy: + raise ValueError("User-defined dtypes cannot be saved " + "when allow_pickle=False") + if pickle_kwargs is None: + pickle_kwargs = {} + pickle.dump(array, fp, protocol=4, **pickle_kwargs) + elif array.flags.f_contiguous and not array.flags.c_contiguous: + if isfileobj(fp): + array.T.tofile(fp) + else: + for chunk in numpy.nditer( + array, flags=['external_loop', 'buffered', 'zerosize_ok'], + buffersize=buffersize, order='F'): + fp.write(chunk.tobytes('C')) + elif isfileobj(fp): + array.tofile(fp) + else: + for chunk in numpy.nditer( + array, flags=['external_loop', 'buffered', 'zerosize_ok'], + buffersize=buffersize, order='C'): + fp.write(chunk.tobytes('C')) + + +@set_module("numpy.lib.format") +def read_array(fp, allow_pickle=False, pickle_kwargs=None, *, + max_header_size=_MAX_HEADER_SIZE): + """ + Read an array from an NPY file. + + Parameters + ---------- + fp : file_like object + If this is not a real file object, then this may take extra memory + and time. + allow_pickle : bool, optional + Whether to allow writing pickled data. Default: False + pickle_kwargs : dict + Additional keyword arguments to pass to pickle.load. These are only + useful when loading object arrays saved on Python 2. + max_header_size : int, optional + Maximum allowed size of the header. Large headers may not be safe + to load securely and thus require explicitly passing a larger value. + See :py:func:`ast.literal_eval()` for details. + This option is ignored when `allow_pickle` is passed. In that case + the file is by definition trusted and the limit is unnecessary. + + Returns + ------- + array : ndarray + The array from the data on disk. + + Raises + ------ + ValueError + If the data is invalid, or allow_pickle=False and the file contains + an object array. + + """ + if allow_pickle: + # Effectively ignore max_header_size, since `allow_pickle` indicates + # that the input is fully trusted. + max_header_size = 2**64 + + version = read_magic(fp) + _check_version(version) + shape, fortran_order, dtype = _read_array_header( + fp, version, max_header_size=max_header_size) + if len(shape) == 0: + count = 1 + else: + count = numpy.multiply.reduce(shape, dtype=numpy.int64) + + # Now read the actual data. + if dtype.hasobject: + # The array contained Python objects. We need to unpickle the data. + if not allow_pickle: + raise ValueError("Object arrays cannot be loaded when " + "allow_pickle=False") + if pickle_kwargs is None: + pickle_kwargs = {} + try: + array = pickle.load(fp, **pickle_kwargs) + except UnicodeError as err: + # Friendlier error message + raise UnicodeError("Unpickling a python object failed: %r\n" + "You may need to pass the encoding= option " + "to numpy.load" % (err,)) from err + else: + if isfileobj(fp): + # We can use the fast fromfile() function. + array = numpy.fromfile(fp, dtype=dtype, count=count) + else: + # This is not a real file. We have to read it the + # memory-intensive way. + # crc32 module fails on reads greater than 2 ** 32 bytes, + # breaking large reads from gzip streams. Chunk reads to + # BUFFER_SIZE bytes to avoid issue and reduce memory overhead + # of the read. In non-chunked case count < max_read_count, so + # only one read is performed. + + # Use np.ndarray instead of np.empty since the latter does + # not correctly instantiate zero-width string dtypes; see + # https://github.com/numpy/numpy/pull/6430 + array = numpy.ndarray(count, dtype=dtype) + + if dtype.itemsize > 0: + # If dtype.itemsize == 0 then there's nothing more to read + max_read_count = BUFFER_SIZE // min(BUFFER_SIZE, dtype.itemsize) + + for i in range(0, count, max_read_count): + read_count = min(max_read_count, count - i) + read_size = int(read_count * dtype.itemsize) + data = _read_bytes(fp, read_size, "array data") + array[i:i + read_count] = numpy.frombuffer(data, dtype=dtype, + count=read_count) + + if array.size != count: + raise ValueError( + "Failed to read all data for array. " + f"Expected {shape} = {count} elements, " + f"could only read {array.size} elements. " + "(file seems not fully written?)" + ) + + if fortran_order: + array.shape = shape[::-1] + array = array.transpose() + else: + array.shape = shape + + return array + + +@set_module("numpy.lib.format") +def open_memmap(filename, mode='r+', dtype=None, shape=None, + fortran_order=False, version=None, *, + max_header_size=_MAX_HEADER_SIZE): + """ + Open a .npy file as a memory-mapped array. + + This may be used to read an existing file or create a new one. + + Parameters + ---------- + filename : str or path-like + The name of the file on disk. This may *not* be a file-like + object. + mode : str, optional + The mode in which to open the file; the default is 'r+'. In + addition to the standard file modes, 'c' is also accepted to mean + "copy on write." See `memmap` for the available mode strings. + dtype : data-type, optional + The data type of the array if we are creating a new file in "write" + mode, if not, `dtype` is ignored. The default value is None, which + results in a data-type of `float64`. + shape : tuple of int + The shape of the array if we are creating a new file in "write" + mode, in which case this parameter is required. Otherwise, this + parameter is ignored and is thus optional. + fortran_order : bool, optional + Whether the array should be Fortran-contiguous (True) or + C-contiguous (False, the default) if we are creating a new file in + "write" mode. + version : tuple of int (major, minor) or None + If the mode is a "write" mode, then this is the version of the file + format used to create the file. None means use the oldest + supported version that is able to store the data. Default: None + max_header_size : int, optional + Maximum allowed size of the header. Large headers may not be safe + to load securely and thus require explicitly passing a larger value. + See :py:func:`ast.literal_eval()` for details. + + Returns + ------- + marray : memmap + The memory-mapped array. + + Raises + ------ + ValueError + If the data or the mode is invalid. + OSError + If the file is not found or cannot be opened correctly. + + See Also + -------- + numpy.memmap + + """ + if isfileobj(filename): + raise ValueError("Filename must be a string or a path-like object." + " Memmap cannot use existing file handles.") + + if 'w' in mode: + # We are creating the file, not reading it. + # Check if we ought to create the file. + _check_version(version) + # Ensure that the given dtype is an authentic dtype object rather + # than just something that can be interpreted as a dtype object. + dtype = numpy.dtype(dtype) + if dtype.hasobject: + msg = "Array can't be memory-mapped: Python objects in dtype." + raise ValueError(msg) + d = { + "descr": dtype_to_descr(dtype), + "fortran_order": fortran_order, + "shape": shape, + } + # If we got here, then it should be safe to create the file. + with open(os.fspath(filename), mode + 'b') as fp: + _write_array_header(fp, d, version) + offset = fp.tell() + else: + # Read the header of the file first. + with open(os.fspath(filename), 'rb') as fp: + version = read_magic(fp) + _check_version(version) + + shape, fortran_order, dtype = _read_array_header( + fp, version, max_header_size=max_header_size) + if dtype.hasobject: + msg = "Array can't be memory-mapped: Python objects in dtype." + raise ValueError(msg) + offset = fp.tell() + + if fortran_order: + order = 'F' + else: + order = 'C' + + # We need to change a write-only mode to a read-write mode since we've + # already written data to the file. + if mode == 'w+': + mode = 'r+' + + marray = numpy.memmap(filename, dtype=dtype, shape=shape, order=order, + mode=mode, offset=offset) + + return marray + + +def _read_bytes(fp, size, error_template="ran out of data"): + """ + Read from file-like object until size bytes are read. + Raises ValueError if not EOF is encountered before size bytes are read. + Non-blocking objects only supported if they derive from io objects. + + Required as e.g. ZipExtFile in python 2.6 can return less data than + requested. + """ + data = b"" + while True: + # io files (default in python3) return None or raise on + # would-block, python2 file will truncate, probably nothing can be + # done about that. note that regular files can't be non-blocking + try: + r = fp.read(size - len(data)) + data += r + if len(r) == 0 or len(data) == size: + break + except BlockingIOError: + pass + if len(data) != size: + msg = "EOF: reading %s, expected %d bytes got %d" + raise ValueError(msg % (error_template, size, len(data))) + else: + return data + + +@set_module("numpy.lib.format") +def isfileobj(f): + if not isinstance(f, (io.FileIO, io.BufferedReader, io.BufferedWriter)): + return False + try: + # BufferedReader/Writer may raise OSError when + # fetching `fileno()` (e.g. when wrapping BytesIO). + f.fileno() + return True + except OSError: + return False |