mdw@git.distorted.org.uk Git - mLib-python/blob - pkbuf.pyx

   1 ### -*-pyrex-*-
   2 ###
   3 ### Packet buffering
   4 ###
   5 ### (c) 2005 Straylight/Edgeware
   6 ###
   7
   8 ###----- Licensing notice ---------------------------------------------------
   9 ###
  10 ### This file is part of the Python interface to mLib.
  11 ###
  12 ### mLib/Python is free software; you can redistribute it and/or modify
  13 ### it under the terms of the GNU General Public License as published by
  14 ### the Free Software Foundation; either version 2 of the License, or
  15 ### (at your option) any later version.
  16 ###
  17 ### mLib/Python is distributed in the hope that it will be useful,
  18 ### but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ### GNU General Public License for more details.
  21 ###
  22 ### You should have received a copy of the GNU General Public License
  23 ### along with mLib/Python; if not, write to the Free Software Foundation,
  24 ### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25
  26 cdef class PacketBuffer:
  27   """
  28   PacketBuffer([packetproc = None], [eofproc = None])
  29
  30   Split an incoming stream into packets.
  31   """
  32   cdef pkbuf pk
  33   cdef _packet
  34   cdef _eof
  35   def __cinit__(me, packetproc = None, eofproc = None, *hunoz, **hukairz):
  36     pkbuf_init(&me.pk, _pkfunc, <void *>me)
  37     me._packet = _checkcallable(packetproc, 'packet proc')
  38     me._eof = _checkcallable(eofproc, 'eof proc')
  39   def __dealloc__(me):
  40     pkbuf_destroy(&me.pk)
  41   property activep:
  42     """PK.activep -> BOOL: is the buffer still active?"""
  43     def __get__(me):
  44       return _tobool(me.pk.f & PKBUF_ENABLE)
  45   property want:
  46     """PK.want -> INT: size of next packet to return"""
  47     def __get__(me):
  48       return me.pk.want
  49     def __set__(me, want):
  50       if want <= 0:
  51         raise TypeError, 'want must be positive'
  52       pkbuf_want(&me.pk, pk)
  53   property packetproc:
  54     """PK.packetproc -> FUNC: call FUNC(PACKET) on each packet"""
  55     def __get__(me):
  56       return me._packet
  57     def __set__(me, proc):
  58       me._line = _checkcallable(proc, 'packet proc')
  59     def __del__(me):
  60       me._line = None
  61   property eofproc:
  62     """PK.eofproc -> FUNC: call FUNC() at end-of-file"""
  63     def __get__(me):
  64       return me._eof
  65     def __set__(me, proc):
  66       me._eof = _checkcallable(proc, 'eof proc')
  67     def __del__(me):
  68       me._eof = None
  69   def enable(me):
  70     """PK.enable(): enable the buffer, allowing packets to be emitted"""
  71     if me.pk.f & PKBUF_ENABLE:
  72       raise ValueError, 'already enabled'
  73     me.pk.f = me.pk.f | PKBUF_ENABLE
  74     me.enabled()
  75     return me
  76   def disable(me):
  77     """PK.disable(): disable the buffer, suspending packet emission"""
  78     if not (me.pk.f & PKBUF_ENABLE):
  79       raise ValueError, 'already disabled'
  80     me.pk.f = me.pk.f & ~PKBUF_ENABLE
  81     me.disabled()
  82     return me
  83   def close(me):
  84     """PK.close(): report the end of the input stream"""
  85     if not (me.pk.f & PKBUF_ENABLE):
  86       raise ValueError, 'buffer disabled'
  87     pkbuf_close(&me.pk)
  88     return me
  89   property free:
  90     """PK.free -> INT: amount of space remaining in buffer"""
  91     def __get__(me):
  92       cdef unsigned char *p
  93       return pkbuf_free(&me.pk, &p)
  94   def flush(me, str):
  95     """PK.flush(STR) -> insert STR into the buffer and emit packets"""
  96     cdef Py_ssize_t len
  97     cdef unsigned char *p
  98     cdef unsigned char *q
  99     cdef size_t n
 100     PyObject_AsReadBuffer(str, <cvp *>&p, &len)
 101     while len > 0:
 102       n = pkbuf_free(&me.pk, &q)
 103       if n > len:
 104         n = len
 105       memcpy(q, p, n)
 106       p = p + n
 107       len = len - n
 108       if not (me.pk.f & PKBUF_ENABLE):
 109         break
 110       pkbuf_flush(&me.pk, q, n)
 111     return PyString_FromStringAndSize(<char *>p, len)
 112   def enabled(me):
 113     """PK.enabled(): called when buffer is enabled"""
 114     pass
 115   def disabled(me):
 116     """PK.disabled(): called when buffer is disabled"""
 117     pass
 118   def packet(me, pk):
 119     """PK.packet(PACKET): called for each completed packet"""
 120     return _maybecall(me._packet, (pk,))
 121   def eof(me):
 122     """PK.eof(): called at end-of-file"""
 123     return _maybecall(me._eof, ())
 124
 125 cdef void _pkfunc(unsigned char *p, size_t n, pkbuf *pk,
 126                   size_t *keep, void *arg):
 127   cdef PacketBuffer pb
 128   cdef void *rp
 129   cdef Py_ssize_t rn
 130   pb = <PacketBuffer>arg
 131   if p is NULL:
 132     pb.eof()
 133   else:
 134     r = pb.packet(PyString_FromStringAndSize(<char *>p, n))
 135     if r is not None:
 136       PyObject_AsReadBuffer(r, <cvp *>&rp, &rn)
 137       if rn > n:
 138         raise ValueError, 'remaining buffer too large'
 139       if rn:
 140         memcpy(p + n - rn, rp, rn)
 141         keep[0] = rn
 142
 143 ###----- That's all, folks --------------------------------------------------