text: import sys, types
  from .lock import allocate_lock
  from .error import CDefError
  from . import model
  
  try:
      callable
  except NameError:
      # Python 3.1
      from collections import Callable
      callable = lambda x: isinstance(x, Callable)
  
  try:
      basestring
  except NameError:
      # Python 3.x
      basestring = str
  
  _unspecified = object()
  
  
  
  class FFI(object):
      r'''
      The main top-level class that you instantiate once, or once per module.
  
      Example usage:
  
          ffi = FFI()
          ffi.cdef("""
              int printf(const char *, ...);
          """)
  
          C = ffi.dlopen(None)   # standard library
          -or-
          C = ffi.verify()  # use a C compiler: verify the decl above is right
  
          C.printf("hello, %s!\n", ffi.new("char[]", "world"))
      '''
  
      def __init__(self, backend=None):
          """Create an FFI instance.  The 'backend' argument is used to
          select a non-default backend, mostly for tests.
          """
          if backend is None:
              # You need PyPy (>= 2.0 beta), or a CPython (>= 2.6) with
              # _cffi_backend.so compiled.
              import _cffi_backend as backend
              from . import __version__
              if backend.__version__ != __version__:
                  # bad version!  Try to be as explicit as possible.
                  if hasattr(backend, '__file__'):
                      # CPython
                      raise Exception("Version mismatch: this is the 'cffi' package version %s, located in %r.  When we import the top-level '_cffi_backend' extension module, we get version %s, located in %r.  The two versions should be equal; check your installation." % (
                          __version__, __file__,
                          backend.__version__, backend.__file__))
                  else:
                      # PyPy
                      raise Exception("Version mismatch: this is the 'cffi' package version %s, located in %r.  This interpreter comes with a built-in '_cffi_backend' module, which is version %s.  The two versions should be equal; check your installation." % (
                          __version__, __file__, backend.__version__))
              # (If you insist you can also try to pass the option
              # 'backend=backend_ctypes.CTypesBackend()', but don't
              # rely on it!  It's probably not going to work well.)
  
          from . import cparser
          self._backend = backend
          self._lock = allocate_lock()
          self._parser = cparser.Parser()
          self._cached_btypes = {}
          self._parsed_types = types.ModuleType('parsed_types').__dict__
          self._new_types = types.ModuleType('new_types').__dict__
          self._function_caches = []
          self._libraries = []
          self._cdefsources = []
          self._included_ffis = []
          self._windows_unicode = None
          self._init_once_cache = {}
          self._cdef_version = None
          self._embedding = None
          self._typecache = model.get_typecache(backend)
          if hasattr(backend, 'set_ffi'):
              backend.set_ffi(self)
          for name in list(backend.__dict__):
              if name.startswith('RTLD_'):
                  setattr(self, name, getattr(backend, name))
          #
          with self._lock:
              self.BVoidP = self._get_cached_btype(model.voidp_type)
              self.BCharA = self._get_cached_btype(model.char_array_type)
          if isinstance(backend, types.ModuleType):
              # _cffi_backend: attach these constants to the class
              if not hasattr(FFI, 'NULL'):
                  FFI.NULL = self.cast(self.BVoidP, 0)
                  FFI.CData, FFI.CType = backend._get_types()
          else:
              # ctypes backend: attach these constants to the instance
              self.NULL = self.cast(self.BVoidP, 0)
              self.CData, self.CType = backend._get_types()
          self.buffer = backend.buffer
  
      def cdef(self, csource, override=False, packed=False, pack=None):
          """Parse the given C source.  This registers all declared functions,
          types, and global variables.  The functions and global variables can
          then be accessed via either 'ffi.dlopen()' or 'ffi.verify()'.
          The types can be used in 'ffi.new()' and other functions.
          If 'packed' is specified as True, all structs declared inside this
          cdef are packed, i.e. laid out without any field alignment at all.
          Alternatively, 'pack' can be a small integer, and requests for
          alignment greater than that are ignored (pack=1 is equivalent to
          packed=True).
          """
          self._cdef(csource, override=override, packed=packed, pack=pack)
  
      def embedding_api(self, csource, packed=False, pack=None):
          self._cdef(csource, packed=packed, pack=pack, dllexport=True)
          if self._embedding is None:
              self._embedding = ''
  
      def _cdef(self, csource, override=False, **options):
          if not isinstance(csource, str):    # unicode, on Python 2
              if not isinstance(csource, basestring):
                  raise TypeError("cdef() argument must be a string")
              csource = csource.encode('ascii')
          with self._lock:
              self._cdef_version = object()
              self._parser.parse(csource, override=override, **options)
              self._cdefsources.append(csource)
              if override:
                  for cache in self._function_caches:
                      cache.clear()
              finishlist = self._parser._recomplete
              if finishlist:
                  self._parser._recomplete = []
                  for tp in finishlist:
                      tp.finish_backend_type(self, finishlist)
  
      def dlopen(self, name, flags=0):
          """Load and return a dynamic library identified by 'name'.
          The standard C library can be loaded by passing None.
          Note that functions and types declared by 'ffi.cdef()' are not
          linked to a particular library, just like C headers; in the
          library we only look for the actual (untyped) symbols.
          """
          if not (isinstance(name, basestring) or
                  name is None or
                  isinstance(name, self.CData)):
              raise TypeError("dlopen(name): name must be a file name, None, "
                              "or an already-opened 'void *' handle")
          with self._lock:
              lib, function_cache = _make_ffi_library(self, name, flags)
              self._function_caches.append(function_cache)
              self._libraries.append(lib)
          return lib
  
      def dlclose(self, lib):
          """Close a library obtained with ffi.dlopen().  After this call,
          access to functions or variables from the library will fail
          (possibly with a segmentation fault).
          """
          type(lib).__cffi_close__(lib)
  
      def _typeof_locked(self, cdecl):
          # call me with the lock!
          key = cdecl
          if key in self._parsed_types:
              return self._parsed_types[key]
          #
          if not isinstance(cdecl, str):    # unicode, on Python 2
              cdecl = cdecl.encode('ascii')
          #
          type = self._parser.parse_type(cdecl)
          really_a_function_type = type.is_raw_function
          if really_a_function_type:
              type = type.as_function_pointer()
          btype = self._get_cached_btype(type)
          result = btype, really_a_function_type
          self._parsed_types[key] = result
          return result
  
      def _typeof(self, cdecl, consider_function_as_funcptr=False):
          # string -> ctype object
          try:
              result = self._parsed_types[cdecl]
          except KeyError:
              with self._lock:
                  result = self._typeof_locked(cdecl)
          #
          btype, really_a_function_type = result
          if really_a_function_type and not consider_function_as_funcptr:
              raise CDefError("the type %r is a function type, not a "
                              "pointer-to-function type" % (cdecl,))
          return btype
  
      def typeof(self, cdecl):
          """Parse the C type given as a string and return the
          corresponding <ctype> object.
          It can also be used on 'cdata' instance to get its C type.
          """
          if isinstance(cdecl, basestring):
              return self._typeof(cdecl)
          if isinstance(cdecl, self.CData):
              return self._backend.typeof(cdecl)
          if isinstance(cdecl, types.BuiltinFunctionType):
              res = _builtin_function_type(cdecl)
              if res is not None:
                  return res
          if (isinstance(cdecl, types.FunctionType)
                  and hasattr(cdecl, '_cffi_base_type')):
              with self._lock:
                  return self._get_cached_btype(cdecl._cffi_base_type)
          raise TypeError(type(cdecl))
  
      def sizeof(self, cdecl):
          """Return the size in bytes of the argument.  It can be a
          string naming a C type, or a 'cdata' instance.
          """
          if isinstance(cdecl, basestring):
              BType = self._typeof(cdecl)
              return self._backend.sizeof(BType)
          else:
              return self._backend.sizeof(cdecl)
  
      def alignof(self, cdecl):
          """Return the natural alignment size in bytes of the C type
          given as a string.
          """
          if isinstance(cdecl, basestring):
              cdecl = self._typeof(cdecl)
          return self._backend.alignof(cdecl)
  
      def offsetof(self, cdecl, *fields_or_indexes):
          """Return the offset of the named field inside the given
          structure or array, which must be given as a C type name.
          You can give several field names in case of nested structures.
          You can also give numeric values which correspond to array
          items, in case of an array type.
          """
          if isinstance(cdecl, basestring):
              cdecl = self._typeof(cdecl)
          return self._typeoffsetof(cdecl, *fields_or_indexes)[1]
  
      def new(self, cdecl, init=None):
          """Allocate an instance according to the specified C type and
          return a pointer to it.  The specified C type must be either a
          pointer or an array: ``new('X *')`` allocates an X and returns
          a pointer to it, whereas ``new('X[n]')`` allocates an array of
          n X'es and returns an array referencing it (which works
          mostly like a pointer, like in C).  You can also use
          ``new('X[]', n)`` to allocate an array of a non-constant
          length n.
  
          The memory is initialized following the rules of declaring a
          global variable in C: by default it is zero-initialized, but
          an explicit initializer can be given which can be used to
          fill all or part of the memory.
  
          When the returned <cdata> object goes out of scope, the memory
          is freed.  In other words the returned <cdata> object has
          ownership of the value of type 'cdecl' that it points to.  This
          means that the raw data can be used as long as this object is
          kept alive, but must not be used for a longer time.  Be careful
          about that when copying the pointer to the memory somewhere
          else, e.g. into another structure.
          """
          if isinstance(cdecl, basestring):
              cdecl = self._typeof(cdecl)
          return self._backend.newp(cdecl, init)
  
      def new_allocator(self, alloc=None, free=None,
                        should_clear_after_alloc=True):
          """Return a new allocator, i.e. a function that behaves like ffi.new()
          but uses the provided low-level 'alloc' and 'free' functions.
  
          'alloc' is called with the size as argument.  If it returns NULL, a
          MemoryError is raised.  'free' is called with the result of 'alloc'
          as argument.  Both can be either Python function or directly C
          functions.  If 'free' is None, then no free function is called.
          If both 'alloc' and 'free' are None, the default is used.
  
          If 'should_clear_after_alloc' is set to False, then the memory
          returned by 'alloc' is assumed to be already cleared (or you are
          fine with garbage); otherwise CFFI will clear it.
          """
          compiled_ffi = self._backend.FFI()
          allocator = compiled_ffi.new_allocator(alloc, free,
                                                 should_clear_after_alloc)
          def allocate(cdecl, init=None):
              if isinstance(cdecl, basestring):
                  cdecl = self._typeof(cdecl)
              return allocator(cdecl, init)
          return allocate
  
      def cast(self, cdecl, source):
          """Similar to a C cast: returns an instance of the named C
          type initialized with the given 'source'.  The source is
          casted between integers or pointers of any type.
          """
          if isinstance(cdecl, basestring):
              cdecl = self._typeof(cdecl)
          return self._backend.cast(cdecl, source)
  
      def string(self, cdata, maxlen=-1):
          """Return a Python string (or unicode string) from the 'cdata'.
          If 'cdata' is a pointer or array of characters or bytes, returns
          the null-terminated string.  The returned string extends until
          the first null character, or at most 'maxlen' characters.  If
          'cdata' is an array then 'maxlen' defaults to its length.
  
          If 'cdata' is a pointer or array of wchar_t, returns a unicode
          string following the same rules.
  
          If 'cdata' is a single character or byte or a wchar_t, returns
          it as a string or unicode string.
  
          If 'cdata' is an enum, returns the value of the enumerator as a
          string, or 'NUMBER' if the value is out of range.
          """
          return self._backend.string(cdata, maxlen)
  
      def unpack(self, cdata, length):
          """Unpack an array of C data of the given length,
          returning a Python string/unicode/list.
  
          If 'cdata' is a pointer to 'char', returns a byte string.
          It does not stop at the first null.  This is equivalent to:
          ffi.buffer(cdata, length)[:]
  
          If 'cdata' is a pointer to 'wchar_t', returns a unicode string.
          'length' is measured in wchar_t's; it is not the size in bytes.
  
          If 'cdata' is a pointer to anything else, returns a list of
          'length' items.  This is a faster equivalent to:
          [cdata[i] for i in range(length)]
          """
          return self._backend.unpack(cdata, length)
  
     #def buffer(self, cdata, size=-1):
     #    """Return a read-write buffer object that references the raw C data
     #    pointed to by the given 'cdata'.  The 'cdata' must be a pointer or
     #    an array.  Can be passed to functions expecting a buffer, or directly
     #    manipulated with:
     #
     #        buf[:]          get a copy of it in a regular string, or
     #        buf[idx]        as a single character
     #        buf[:] = ...
     #        buf[idx] = ...  change the content
     #    """
     #    note that 'buffer' is a type, set on this instance by __init__
  
      def from_buffer(self, cdecl, python_buffer=_unspecified,
                      require_writable=False):
          """Return a cdata of the given type pointing to the data of the
          given Python object, which must support the buffer interface.
          Note that this is not meant to be used on the built-in types
          str or unicode (you can build 'char[]' arrays explicitly)
          but only on objects containing large quantities of raw data
          in some other format, like 'array.array' or numpy arrays.
  
          The first argument is optional and default to 'char[]'.
          """
          if python_buffer is _unspecified:
              cdecl, python_buffer = self.BCharA, cdecl
          elif isinstance(cdecl, basestring):
              cdecl = self._typeof(cdecl)
          return self._backend.from_buffer(cdecl, python_buffer,
                                           require_writable)
  
      def memmove(self, dest, src, n):
          """ffi.memmove(dest, src, n) copies n bytes of memory from src to dest.
  
          Like the C function memmove(), the memory areas may overlap;
          apart from that it behaves like the C function memcpy().
  
          'src' can be any cdata ptr or array, or any Python buffer object.
          'dest' can be any cdata ptr or array, or a writable Python buffer
          object.  The size to copy, 'n', is always measured in bytes.
  
          Unlike other methods, this one supports all Python buffer including
          byte strings and bytearrays---but it still does not support
          non-contiguous buffers.
          """
          return self._backend.memmove(dest, src, n)
  
      def callback(self, cdecl, python_callable=None, error=None, onerror=None):
          """Return a callback object or a decorator making such a
          callback object.  'cdecl' must name a C function pointer type.
          The callback invokes the specified 'python_callable' (which may
          be provided either directly or via a decorator).  Important: the
          callback object must be manually kept alive for as long as the
          callback may be invoked from the C level.
          """
          def callback_decorator_wrap(python_callable):
              if not callable(python_callable):
                  raise TypeError("the 'python_callable' argument "
                                  "is not callable")
              return self._backend.callback(cdecl, python_callable,
                                            error, onerror)
          if isinstance(cdecl, basestring):
              cdecl = self._typeof(cdecl, consider_function_as_funcptr=True)
          if python_callable is None:
              return callback_decorator_wrap                # decorator mode
          else:
              return callback_decorator_wrap(python_callable)  # direct mode
  
      def getctype(self, cdecl, replace_with=''):
          """Return a string giving the C type 'cdecl', which may be itself
          a string or a <ctype> object.  If 'replace_with' is given, it gives
          extra text to append (or insert for more complicated C types), like
          a variable name, or '*' to get actually the C type 'pointer-to-cdecl'.
          """
          if isinstance(cdecl, basestring):
              cdecl = self._typeof(cdecl)
          replace_with = replace_with.strip()
          if (replace_with.startswith('*')
                  and '&[' in self._backend.getcname(cdecl, '&')):
              replace_with = '(%s)' % replace_with
          elif replace_with and not replace_with[0] in '[(':
              replace_with = ' ' + replace_with
          return self._backend.getcname(cdecl, replace_with)
  
      def gc(self, cdata, destructor, size=0):
          """Return a new cdata object that points to the same
          data.  Later, when this new cdata object is garbage-collected,
          'destructor(old_cdata_object)' will be called.
  
          The optional 'size' gives an estimate of the size, used to
          trigger the garbage collection more eagerly.  So far only used
          on PyPy.  It tells the GC that the returned object keeps alive
          roughly 'size' bytes of external memory.
          """
          return self._backend.gcp(cdata, destructor, size)
  
      def _get_cached_btype(self, type):
          assert self._lock.acquire(False) is False
          # call me with the lock!
          try:
              BType = self._cached_btypes[type]
          except KeyError:
              finishlist = []
              BType = type.get_cached_btype(self, finishlist)
              for type in finishlist:
                  type.finish_backend_type(self, finishlist)
          return BType
  
      def verify(self, source='', tmpdir=None, **kwargs):
          """Verify that the current ffi signatures compile on this
          machine, and return a dynamic library object.  The dynamic
          library can be used to call functions and access global
          variables declared in this 'ffi'.  The library is compiled
          by the C compiler: it gives you C-level API compatibility
          (including calling macros).  This is unlike 'ffi.dlopen()',
          which requires binary compatibility in the signatures.
          """
          from .verifier import Verifier, _caller_dir_pycache
          #
          # If set_unicode(True) was called, insert the UNICODE and
          # _UNICODE macro declarations
          if self._windows_unicode:
              self._apply_windows_unicode(kwargs)
          #
          # Set the tmpdir here, and not in Verifier.__init__: it picks
          # up the caller's directory, which we want to be the caller of
          # ffi.verify(), as opposed to the caller of Veritier().
          tmpdir = tmpdir or _caller_dir_pycache()
          #
          # Make a Verifier() and use it to load the library.
          self.verifier = Verifier(self, source, tmpdir, **kwargs)
          lib = self.verifier.load_library()
          #
          # Save the loaded library for keep-alive purposes, even
          # if the caller doesn't keep it alive itself (it should).
          self._libraries.append(lib)
          return lib
  
      def _get_errno(self):
          return self._backend.get_errno()
      def _set_errno(self, errno):
          self._backend.set_errno(errno)
      errno = property(_get_errno, _set_errno, None,
                       "the value of 'errno' from/to the C calls")
  
      def getwinerror(self, code=-1):
          return self._backend.getwinerror(code)
  
      def _pointer_to(self, ctype):
          with self._lock:
              return model.pointer_cache(self, ctype)
  
      def addressof(self, cdata, *fields_or_indexes):
          """Return the address of a <cdata 'struct-or-union'>.
          If 'fields_or_indexes' are given, returns the address of that
          field or array item in the structure or array, recursively in
          case of nested structures.
          """
          try:
              ctype = self._backend.typeof(cdata)
          except TypeError:
              if '__addressof__' in type(cdata).__dict__:
                  return type(cdata).__addressof__(cdata, *fields_or_indexes)
              raise
          if fields_or_indexes:
              ctype, offset = self._typeoffsetof(ctype, *fields_or_indexes)
          else:
              if ctype.kind == "pointer":
                  raise TypeError("addressof(pointer)")
              offset = 0
          ctypeptr = self._pointer_to(ctype)
          return self._backend.rawaddressof(ctypeptr, cdata, offset)
  
      def _typeoffsetof(self, ctype, field_or_index, *fields_or_indexes):
          ctype, offset = self._backend.typeoffsetof(ctype, field_or_index)
          for field1 in fields_or_indexes:
              ctype, offset1 = self._backend.typeoffsetof(ctype, field1, 1)
              offset += offset1
          return ctype, offset
  
      def include(self, ffi_to_include):
          """Includes the typedefs, structs, unions and enums defined
          in another FFI instance.  Usage is similar to a #include in C,
          where a part of the program might include types defined in
          another part for its own usage.  Note that the include()
          method has no effect on functions, constants and global
          variables, which must anyway be accessed directly from the
          lib object returned by the original FFI instance.
          """
          if not isinstance(ffi_to_include, FFI):
              raise TypeError("ffi.include() expects an argument that is also of"
                              " type cffi.FFI, not %r" % (
                                  type(ffi_to_include).__name__,))
          if ffi_to_include is self:
              raise ValueError("self.include(self)")
          with ffi_to_include._lock:
              with self._lock:
                  self._parser.include(ffi_to_include._parser)
                  self._cdefsources.append('[')
                  self._cdefsources.extend(ffi_to_include._cdefsources)
                  self._cdefsources.append(']')
                  self._included_ffis.append(ffi_to_include)
  
      def new_handle(self, x):
          return self._backend.newp_handle(self.BVoidP, x)
  
      def from_handle(self, x):
          return self._backend.from_handle(x)
  
      def release(self, x):
          self._backend.release(x)
  
      def set_unicode(self, enabled_flag):
          """Windows: if 'enabled_flag' is True, enable the UNICODE and
          _UNICODE defines in C, and declare the types like TCHAR and LPTCSTR
          to be (pointers to) wchar_t.  If 'enabled_flag' is False,
          declare these types to be (pointers to) plain 8-bit characters.
          This is mostly for backward compatibility; you usually want True.
          """
          if self._windows_unicode is not None:
              raise ValueError("set_unicode() can only be called once")
          enabled_flag = bool(enabled_flag)
          if enabled_flag:
              self.cdef("typedef wchar_t TBYTE;"
                        "typedef wchar_t TCHAR;"
                        "typedef const wchar_t *LPCTSTR;"
                        "typedef const wchar_t *PCTSTR;"
                        "typedef wchar_t *LPTSTR;"
                        "typedef wchar_t *PTSTR;"
                        "typedef TBYTE *PTBYTE;"
                        "typedef TCHAR *PTCHAR;")
          else:
              self.cdef("typedef char TBYTE;"
                        "typedef char TCHAR;"
                        "typedef const char *LPCTSTR;"
                        "typedef const char *PCTSTR;"
                        "typedef char *LPTSTR;"
                        "typedef char *PTSTR;"
                        "typedef TBYTE *PTBYTE;"
                        "typedef TCHAR *PTCHAR;")
          self._windows_unicode = enabled_flag
  
      def _apply_windows_unicode(self, kwds):
          defmacros = kwds.get('define_macros', ())
          if not isinstance(defmacros, (list, tuple)):
              raise TypeError("'define_macros' must be a list or tuple")
          defmacros = list(defmacros) + [('UNICODE', '1'),
                                         ('_UNICODE', '1')]
          kwds['define_macros'] = defmacros
  
      def _apply_embedding_fix(self, kwds):
          # must include an argument like "-lpython2.7" for the compiler
          def ensure(key, value):
              lst = kwds.setdefault(key, [])
              if value not in lst:
                  lst.append(value)
          #
          if '__pypy__' in sys.builtin_module_names:
              import os
              if sys.platform == "win32":
                  # we need 'libpypy-c.lib'.  Current distributions of
                  # pypy (>= 4.1) contain it as 'libs/python27.lib'.
                  pythonlib = "python{0[0]}{0[1]}".format(sys.version_info)
                  if hasattr(sys, 'prefix'):
                      ensure('library_dirs', os.path.join(sys.prefix, 'libs'))
              else:
                  # we need 'libpypy-c.{so,dylib}', which should be by
                  # default located in 'sys.prefix/bin' for installed
                  # systems.
                  if sys.version_info < (3,):
                      pythonlib = "pypy-c"
                  else:
                      pythonlib = "pypy3-c"
                  if hasattr(sys, 'prefix'):
                      ensure('library_dirs', os.path.join(sys.prefix, 'bin'))
              # On uninstalled pypy's, the libpypy-c is typically found in
              # .../pypy/goal/.
              if hasattr(sys, 'prefix'):
                  ensure('library_dirs', os.path.join(sys.prefix, 'pypy', 'goal'))
          else:
              if sys.platform == "win32":
                  template = "python%d%d"
                  if hasattr(sys, 'gettotalrefcount'):
                      template += '_d'
              else:
                  try:
                      import sysconfig
                  except ImportError:    # 2.6
                      from distutils import sysconfig
                  template = "python%d.%d"
                  if sysconfig.get_config_var('DEBUG_EXT'):
                      template += sysconfig.get_config_var('DEBUG_EXT')
              pythonlib = (template %
                      (sys.hexversion >> 24, (sys.hexversion >> 16) & 0xff))
              if hasattr(sys, 'abiflags'):
                  pythonlib += sys.abiflags
          ensure('libraries', pythonlib)
          if sys.platform == "win32":
              ensure('extra_link_args', '/MANIFEST')
  
      def set_source(self, module_name, source, source_extension='.c', **kwds):
          import os
          if hasattr(self, '_assigned_source'):
              raise ValueError("set_source() cannot be called several times "
                               "per ffi object")
          if not isinstance(module_name, basestring):
              raise TypeError("'module_name' must be a string")
          if os.sep in module_name or (os.altsep and os.altsep in module_name):
              raise ValueError("'module_name' must not contain '/': use a dotted "
                               "name to make a 'package.module' location")
          self._assigned_source = (str(module_name), source,
                                   source_extension, kwds)
  
      def set_source_pkgconfig(self, module_name, pkgconfig_libs, source,
                               source_extension='.c', **kwds):
          from . import pkgconfig
          if not isinstance(pkgconfig_libs, list):
              raise TypeError("the pkgconfig_libs argument must be a list "
                              "of package names")
          kwds2 = pkgconfig.flags_from_pkgconfig(pkgconfig_libs)
          pkgconfig.merge_flags(kwds, kwds2)
          self.set_source(module_name, source, source_extension, **kwds)
  
      def distutils_extension(self, tmpdir='build', verbose=True):
          from distutils.dir_util import mkpath
          from .recompiler import recompile
          #
          if not hasattr(self, '_assigned_source'):
              if hasattr(self, 'verifier'):     # fallback, 'tmpdir' ignored
                  return self.verifier.get_extension()
              raise ValueError("set_source() must be called before"
                               " distutils_extension()")
          module_name, source, source_extension, kwds = self._assigned_source
          if source is None:
              raise TypeError("distutils_extension() is only for C extension "
                              "modules, not for dlopen()-style pure Python "
                              "modules")
          mkpath(tmpdir)
          ext, updated = recompile(self, module_name,
                                   source, tmpdir=tmpdir, extradir=tmpdir,
                                   source_extension=source_extension,
                                   call_c_compiler=False, **kwds)
          if verbose:
              if updated:
                  sys.stderr.write("regenerated: %r\n" % (ext.sources[0],))
              else:
                  sys.stderr.write("not modified: %r\n" % (ext.sources[0],))
          return ext
  
      def emit_c_code(self, filename):
          from .recompiler import recompile
          #
          if not hasattr(self, '_assigned_source'):
              raise ValueError("set_source() must be called before emit_c_code()")
          module_name, source, source_extension, kwds = self._assigned_source
          if source is None:
              raise TypeError("emit_c_code() is only for C extension modules, "
                              "not for dlopen()-style pure Python modules")
          recompile(self, module_name, source,
                    c_file=filename, call_c_compiler=False, **kwds)
  
      def emit_python_code(self, filename):
          from .recompiler import recompile
          #
          if not hasattr(self, '_assigned_source'):
              raise ValueError("set_source() must be called before emit_c_code()")
          module_name, source, source_extension, kwds = self._assigned_source
          if source is not None:
              raise TypeError("emit_python_code() is only for dlopen()-style "
                              "pure Python modules, not for C extension modules")
          recompile(self, module_name, source,
                    c_file=filename, call_c_compiler=False, **kwds)
  
      def compile(self, tmpdir='.', verbose=0, target=None, debug=None):
          """The 'target' argument gives the final file name of the
          compiled DLL.  Use '*' to force distutils' choice, suitable for
          regular CPython C API modules.  Use a file name ending in '.*'
          to ask for the system's default extension for dynamic libraries
          (.so/.dll/.dylib).
  
          The default is '*' when building a non-embedded C API extension,
          and (module_name + '.*') when building an embedded library.
          """
          from .recompiler import recompile
          #
          if not hasattr(self, '_assigned_source'):
              raise ValueError("set_source() must be called before compile()")
          module_name, source, source_extension, kwds = self._assigned_source
          return recompile(self, module_name, source, tmpdir=tmpdir,
                           target=target, source_extension=source_extension,
                           compiler_verbose=verbose, debug=debug, **kwds)
  
      def init_once(self, func, tag):
          # Read _init_once_cache[tag], which is either (False, lock) if
          # we're calling the function now in some thread, or (True, result).
          # Don't call setdefault() in most cases, to avoid allocating and
          # immediately freeing a lock; but still use setdefaut() to avoid
          # races.
          try:
              x = self._init_once_cache[tag]
          except KeyError:
              x = self._init_once_cache.setdefault(tag, (False, allocate_lock()))
          # Common case: we got (True, result), so we return the result.
          if x[0]:
              return x[1]
          # Else, it's a lock.  Acquire it to serialize the following tests.
          with x[1]:
              # Read again from _init_once_cache the current status.
              x = self._init_once_cache[tag]
              if x[0]:
                  return x[1]
              # Call the function and store the result back.
              result = func()
              self._init_once_cache[tag] = (True, result)
          return result
  
      def embedding_init_code(self, pysource):
          if self._embedding:
              raise ValueError("embedding_init_code() can only be called once")
          # fix 'pysource' before it gets dumped into the C file:
          # - remove empty lines at the beginning, so it starts at "line 1"
          # - dedent, if all non-empty lines are indented
          # - check for SyntaxErrors
          import re
          match = re.match(r'\s*\n', pysource)
          if match:
              pysource = pysource[match.end():]
          lines = pysource.splitlines() or ['']
          prefix = re.match(r'\s*', lines[0]).group()
          for i in range(1, len(lines)):
              line = lines[i]
              if line.rstrip():
                  while not line.startswith(prefix):
                      prefix = prefix[:-1]
          i = len(prefix)
          lines = [line[i:]+'\n' for line in lines]
          pysource = ''.join(lines)
          #
          compile(pysource, "cffi_init", "exec")
          #
          self._embedding = pysource
  
      def def_extern(self, *args, **kwds):
          raise ValueError("ffi.def_extern() is only available on API-mode FFI "
                           "objects")
  
      def list_types(self):
          """Returns the user type names known to this FFI instance.
          This returns a tuple containing three lists of names:
          (typedef_names, names_of_structs, names_of_unions)
          """
          typedefs = []
          structs = []
          unions = []
          for key in self._parser._declarations:
              if key.startswith('typedef '):
                  typedefs.append(key[8:])
              elif key.startswith('struct '):
                  structs.append(key[7:])
              elif key.startswith('union '):
                  unions.append(key[6:])
          typedefs.sort()
          structs.sort()
          unions.sort()
          return (typedefs, structs, unions)
  
  
  def _load_backend_lib(backend, name, flags):
      import os
      if not isinstance(name, basestring):
          if sys.platform != "win32" or name is not None:
              return backend.load_library(name, flags)
          name = "c"    # Windows: load_library(None) fails, but this works
                        # on Python 2 (backward compatibility hack only)
      first_error = None
      if '.' in name or '/' in name or os.sep in name:
          try:
              return backend.load_library(name, flags)
          except OSError as e:
              first_error = e
      import ctypes.util
      path = ctypes.util.find_library(name)
      if path is None:
          if name == "c" and sys.platform == "win32" and sys.version_info >= (3,):
              raise OSError("dlopen(None) cannot work on Windows for Python 3 "
                            "(see http://bugs.python.org/issue23606)")
          msg = ("ctypes.util.find_library() did not manage "
                 "to locate a library called %r" % (name,))
          if first_error is not None:
              msg = "%s.  Additionally, %s" % (first_error, msg)
          raise OSError(msg)
      return backend.load_library(path, flags)
  
  def _make_ffi_library(ffi, libname, flags):
      backend = ffi._backend
      backendlib = _load_backend_lib(backend, libname, flags)
      #
      def accessor_function(name):
          key = 'function ' + name
          tp, _ = ffi._parser._declarations[key]
          BType = ffi._get_cached_btype(tp)
          value = backendlib.load_function(BType, name)
          library.__dict__[name] = value
      #
      def accessor_variable(name):
          key = 'variable ' + name
          tp, _ = ffi._parser._declarations[key]
          BType = ffi._get_cached_btype(tp)
          read_variable = backendlib.read_variable
          write_variable = backendlib.write_variable
          setattr(FFILibrary, name, property(
              lambda self: read_variable(BType, name),
              lambda self, value: write_variable(BType, name, value)))
      #
      def addressof_var(name):
          try:
              return addr_variables[name]
          except KeyError:
              with ffi._lock:
                  if name not in addr_variables:
                      key = 'variable ' + name
                      tp, _ = ffi._parser._declarations[key]
                      BType = ffi._get_cached_btype(tp)
                      if BType.kind != 'array':
                          BType = model.pointer_cache(ffi, BType)
                      p = backendlib.load_function(BType, name)
                      addr_variables[name] = p
              return addr_variables[name]
      #
      def accessor_constant(name):
          raise NotImplementedError("non-integer constant '%s' cannot be "
                                    "accessed from a dlopen() library" % (name,))
      #
      def accessor_int_constant(name):
          library.__dict__[name] = ffi._parser._int_constants[name]
      #
      accessors = {}
      accessors_version = [False]
      addr_variables = {}
      #
      def update_accessors():
          if accessors_version[0] is ffi._cdef_version:
              return
          #
          for key, (tp, _) in ffi._parser._declarations.items():
              if not isinstance(tp, model.EnumType):
                  tag, name = key.split(' ', 1)
                  if tag == 'function':
                      accessors[name] = accessor_function
                  elif tag == 'variable':
                      accessors[name] = accessor_variable
                  elif tag == 'constant':
                      accessors[name] = accessor_constant
              else:
                  for i, enumname in enumerate(tp.enumerators):
                      def accessor_enum(name, tp=tp, i=i):
                          tp.check_not_partial()
                          library.__dict__[name] = tp.enumvalues[i]
                      accessors[enumname] = accessor_enum
          for name in ffi._parser._int_constants:
              accessors.setdefault(name, accessor_int_constant)
          accessors_version[0] = ffi._cdef_version
      #
      def make_accessor(name):
          with ffi._lock:
              if name in library.__dict__ or name in FFILibrary.__dict__:
                  return    # added by another thread while waiting for the lock
              if name not in accessors:
                  update_accessors()
                  if name not in accessors:
                      raise AttributeError(name)
              accessors[name](name)
      #
      class FFILibrary(object):
          def __getattr__(self, name):
              make_accessor(name)
              return getattr(self, name)
          def __setattr__(self, name, value):
              try:
                  property = getattr(self.__class__, name)
              except AttributeError:
                  make_accessor(name)
                  setattr(self, name, value)
              else:
                  property.__set__(self, value)
          def __dir__(self):
              with ffi._lock:
                  update_accessors()
                  return accessors.keys()
          def __addressof__(self, name):
              if name in library.__dict__:
                  return library.__dict__[name]
              if name in FFILibrary.__dict__:
                  return addressof_var(name)
              make_accessor(name)
              if name in library.__dict__:
                  return library.__dict__[name]
              if name in FFILibrary.__dict__:
                  return addressof_var(name)
              raise AttributeError("cffi library has no function or "
                                   "global variable named '%s'" % (name,))
          def __cffi_close__(self):
              backendlib.close_lib()
              self.__dict__.clear()
      #
      if isinstance(libname, basestring):
          try:
              if not isinstance(libname, str):    # unicode, on Python 2
                  libname = libname.encode('utf-8')
              FFILibrary.__name__ = 'FFILibrary_%s' % libname
          except UnicodeError:
              pass
      library = FFILibrary()
      return library, library.__dict__
  
  def _builtin_function_type(func):
      # a hack to make at least ffi.typeof(builtin_function) work,
      # if the builtin function was obtained by 'vengine_cpy'.
      import sys
      try:
          module = sys.modules[func.__module__]
          ffi = module._cffi_original_ffi
          types_of_builtin_funcs = module._cffi_types_of_builtin_funcs
          tp = types_of_builtin_funcs[func]
      except (KeyError, AttributeError, TypeError):
          return None
      else:
          with ffi._lock:
              return ffi._get_cached_btype(tp)
  