325 lines
10 KiB
Python
325 lines
10 KiB
Python
# ===================================================================
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#
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# Copyright (c) 2014, Legrandin <helderijs@gmail.com>
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions
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# are met:
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#
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# 1. Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in
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# the documentation and/or other materials provided with the
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# distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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# COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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# POSSIBILITY OF SUCH DAMAGE.
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# ===================================================================
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import os
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import abc
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import sys
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from Cryptodome.Util.py3compat import byte_string
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from Cryptodome.Util._file_system import pycryptodome_filename
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#
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# List of file suffixes for Python extensions
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#
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if sys.version_info[0] < 3:
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import imp
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extension_suffixes = []
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for ext, mod, typ in imp.get_suffixes():
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if typ == imp.C_EXTENSION:
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extension_suffixes.append(ext)
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else:
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from importlib import machinery
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extension_suffixes = machinery.EXTENSION_SUFFIXES
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# Which types with buffer interface we support (apart from byte strings)
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_buffer_type = (bytearray, memoryview)
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class _VoidPointer(object):
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@abc.abstractmethod
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def get(self):
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"""Return the memory location we point to"""
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return
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@abc.abstractmethod
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def address_of(self):
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"""Return a raw pointer to this pointer"""
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return
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try:
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# Starting from v2.18, pycparser (used by cffi for in-line ABI mode)
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# stops working correctly when PYOPTIMIZE==2 or the parameter -OO is
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# passed. In that case, we fall back to ctypes.
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# Note that PyPy ships with an old version of pycparser so we can keep
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# using cffi there.
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# See https://github.com/Legrandin/pycryptodome/issues/228
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if '__pypy__' not in sys.builtin_module_names and sys.flags.optimize == 2:
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raise ImportError("CFFI with optimize=2 fails due to pycparser bug.")
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# cffi still uses PyUnicode_GetSize, which was removed in Python 3.12
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# thus leading to a crash on cffi.dlopen()
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# See https://groups.google.com/u/1/g/python-cffi/c/oZkOIZ_zi5k
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if sys.version_info >= (3, 12) and os.name == "nt":
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raise ImportError("CFFI is not compatible with Python 3.12 on Windows")
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from cffi import FFI
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ffi = FFI()
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null_pointer = ffi.NULL
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uint8_t_type = ffi.typeof(ffi.new("const uint8_t*"))
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_Array = ffi.new("uint8_t[1]").__class__.__bases__
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def load_lib(name, cdecl):
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"""Load a shared library and return a handle to it.
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@name, either an absolute path or the name of a library
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in the system search path.
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@cdecl, the C function declarations.
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"""
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if hasattr(ffi, "RTLD_DEEPBIND") and not os.getenv('PYCRYPTODOME_DISABLE_DEEPBIND'):
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lib = ffi.dlopen(name, ffi.RTLD_DEEPBIND)
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else:
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lib = ffi.dlopen(name)
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ffi.cdef(cdecl)
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return lib
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def c_ulong(x):
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"""Convert a Python integer to unsigned long"""
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return x
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c_ulonglong = c_ulong
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c_uint = c_ulong
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c_ubyte = c_ulong
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def c_size_t(x):
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"""Convert a Python integer to size_t"""
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return x
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def create_string_buffer(init_or_size, size=None):
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"""Allocate the given amount of bytes (initially set to 0)"""
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if isinstance(init_or_size, bytes):
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size = max(len(init_or_size) + 1, size)
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result = ffi.new("uint8_t[]", size)
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result[:] = init_or_size
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else:
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if size:
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raise ValueError("Size must be specified once only")
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result = ffi.new("uint8_t[]", init_or_size)
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return result
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def get_c_string(c_string):
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"""Convert a C string into a Python byte sequence"""
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return ffi.string(c_string)
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def get_raw_buffer(buf):
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"""Convert a C buffer into a Python byte sequence"""
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return ffi.buffer(buf)[:]
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def c_uint8_ptr(data):
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if isinstance(data, _buffer_type):
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# This only works for cffi >= 1.7
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return ffi.cast(uint8_t_type, ffi.from_buffer(data))
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elif byte_string(data) or isinstance(data, _Array):
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return data
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else:
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raise TypeError("Object type %s cannot be passed to C code" % type(data))
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class VoidPointer_cffi(_VoidPointer):
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"""Model a newly allocated pointer to void"""
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def __init__(self):
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self._pp = ffi.new("void *[1]")
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def get(self):
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return self._pp[0]
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def address_of(self):
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return self._pp
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def VoidPointer():
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return VoidPointer_cffi()
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backend = "cffi"
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except ImportError:
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import ctypes
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from ctypes import (CDLL, c_void_p, byref, c_ulong, c_ulonglong, c_size_t,
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create_string_buffer, c_ubyte, c_uint)
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from ctypes.util import find_library
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from ctypes import Array as _Array
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null_pointer = None
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cached_architecture = []
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def c_ubyte(c):
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if not (0 <= c < 256):
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raise OverflowError()
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return ctypes.c_ubyte(c)
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def load_lib(name, cdecl):
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if not cached_architecture:
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# platform.architecture() creates a subprocess, so caching the
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# result makes successive imports faster.
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import platform
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cached_architecture[:] = platform.architecture()
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bits, linkage = cached_architecture
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if "." not in name and not linkage.startswith("Win"):
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full_name = find_library(name)
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if full_name is None:
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raise OSError("Cannot load library '%s'" % name)
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name = full_name
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return CDLL(name)
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def get_c_string(c_string):
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return c_string.value
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def get_raw_buffer(buf):
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return buf.raw
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# ---- Get raw pointer ---
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_c_ssize_t = ctypes.c_ssize_t
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_PyBUF_SIMPLE = 0
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_PyObject_GetBuffer = ctypes.pythonapi.PyObject_GetBuffer
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_PyBuffer_Release = ctypes.pythonapi.PyBuffer_Release
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_py_object = ctypes.py_object
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_c_ssize_p = ctypes.POINTER(_c_ssize_t)
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# See Include/object.h for CPython
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# and https://github.com/pallets/click/blob/master/src/click/_winconsole.py
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class _Py_buffer(ctypes.Structure):
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_fields_ = [
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('buf', c_void_p),
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('obj', ctypes.py_object),
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('len', _c_ssize_t),
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('itemsize', _c_ssize_t),
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('readonly', ctypes.c_int),
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('ndim', ctypes.c_int),
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('format', ctypes.c_char_p),
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('shape', _c_ssize_p),
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('strides', _c_ssize_p),
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('suboffsets', _c_ssize_p),
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('internal', c_void_p)
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]
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# Extra field for CPython 2.6/2.7
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if sys.version_info[0] == 2:
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_fields_.insert(-1, ('smalltable', _c_ssize_t * 2))
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def c_uint8_ptr(data):
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if byte_string(data) or isinstance(data, _Array):
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return data
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elif isinstance(data, _buffer_type):
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obj = _py_object(data)
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buf = _Py_buffer()
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_PyObject_GetBuffer(obj, byref(buf), _PyBUF_SIMPLE)
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try:
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buffer_type = ctypes.c_ubyte * buf.len
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return buffer_type.from_address(buf.buf)
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finally:
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_PyBuffer_Release(byref(buf))
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else:
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raise TypeError("Object type %s cannot be passed to C code" % type(data))
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# ---
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class VoidPointer_ctypes(_VoidPointer):
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"""Model a newly allocated pointer to void"""
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def __init__(self):
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self._p = c_void_p()
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def get(self):
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return self._p
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def address_of(self):
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return byref(self._p)
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def VoidPointer():
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return VoidPointer_ctypes()
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backend = "ctypes"
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class SmartPointer(object):
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"""Class to hold a non-managed piece of memory"""
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def __init__(self, raw_pointer, destructor):
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self._raw_pointer = raw_pointer
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self._destructor = destructor
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def get(self):
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return self._raw_pointer
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def release(self):
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rp, self._raw_pointer = self._raw_pointer, None
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return rp
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def __del__(self):
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try:
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if self._raw_pointer is not None:
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self._destructor(self._raw_pointer)
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self._raw_pointer = None
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except AttributeError:
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pass
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def load_pycryptodome_raw_lib(name, cdecl):
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"""Load a shared library and return a handle to it.
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@name, the name of the library expressed as a PyCryptodome module,
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for instance Cryptodome.Cipher._raw_cbc.
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@cdecl, the C function declarations.
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"""
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split = name.split(".")
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dir_comps, basename = split[:-1], split[-1]
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attempts = []
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for ext in extension_suffixes:
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try:
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filename = basename + ext
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full_name = pycryptodome_filename(dir_comps, filename)
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if not os.path.isfile(full_name):
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attempts.append("Not found '%s'" % filename)
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continue
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return load_lib(full_name, cdecl)
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except OSError as exp:
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attempts.append("Cannot load '%s': %s" % (filename, str(exp)))
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raise OSError("Cannot load native module '%s': %s" % (name, ", ".join(attempts)))
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def is_buffer(x):
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"""Return True if object x supports the buffer interface"""
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return isinstance(x, (bytes, bytearray, memoryview))
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def is_writeable_buffer(x):
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return (isinstance(x, bytearray) or
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(isinstance(x, memoryview) and not x.readonly))
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