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env/lib/python3.12/site-packages/Crypto/Util/_raw_api.py

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