#!/usr/bin/python2.7
# -*- coding: utf-8 -*-
# vim:ts=4:sw=4:softtabstop=4:smarttab:expandtab
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# http://www.apache.org/licenses/LICENSE-2.0
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
Defines a Buffer object that uses an anonymous mmap. The object looks like a
StringIO object as well as supporting string operators.
"""
import mmap
# get an anonymous mmap range. Only works on Linux (possibly other Unix)
def get_buffer(size):
return mmap.mmap(-1, size, flags=mmap.MAP_PRIVATE|mmap.MAP_ANONYMOUS,
prot=mmap.PROT_READ|mmap.PROT_WRITE )
# Also emulate a StringIO object.
class Buffer(object):
def __init__(self, size=4096):
self._bufsize = size
self._buf = get_buffer(size)
size = property(lambda s: s._bufsize)
def close(self):
if self._buf is not None:
self._buf.close()
self._buf = None
def getvalue(self):
return self._buf[:]
# auto-delegate most attributes
def __getattr__(self, name):
return getattr(self._buf, name)
def __getitem__(self, i):
return self._buf[i]
def __setitem__(self, i, v):
self._buf[i] = v
def __getslice__(self, i, j):
return self._buf[i:j]
def __setslice__(self, i, j, seq):
self._buf[i:j] = seq
def __iadd__(self, seq):
self._buf.write(seq)
return self
def __len__(self):
return self._buf.tell()
def __str__(self):
return self._buf[0:self._buf.tell()]
