Python _cffi_backend.buffer方法代碼示例

# 需要導入模塊: import _cffi_backend [as 別名]
# 或者: from _cffi_backend import buffer [as 別名]
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) 

# 需要導入模塊: import _cffi_backend [as 別名]
# 或者: from _cffi_backend import buffer [as 別名]
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__ 

# 需要導入模塊: import _cffi_backend [as 別名]
# 或者: from _cffi_backend import buffer [as 別名]
def from_buffer(self, python_buffer):
        """Return a <cdata 'char[]'> that points 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.
        """
        return self._backend.from_buffer(self.BCharA, python_buffer) 

# 需要導入模塊: import _cffi_backend [as 別名]
# 或者: from _cffi_backend import buffer [as 別名]
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) 

# 需要導入模塊: import _cffi_backend [as 別名]
# 或者: from _cffi_backend import buffer [as 別名]
def ctarray_to_bytes(ctarray):
    """
    Convert ctypes array into a bytes object.

    :param ctarray: The ctypes array to convert.
    :return: The converted ctypes array.
    :rtype: bytes
    """
    if not len(ctarray):
        # work around a bug in v3.1 & v3.2 that results in a segfault when len(ctarray) == 0
        return bytes()
    bytes_ = buffer(ctarray) if sys.version_info[0] < 3 else bytes(ctarray)
    return bytes_[:]