/usr/lib/python2.7/dist-packages/nxt/telegram.py is in python-nxt 2.2.2-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 | # nxt.telegram module -- LEGO Mindstorms NXT telegram formatting and parsing
# Copyright (C) 2006 Douglas P Lau
# Copyright (C) 2009 Marcus Wanner
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
'Used by nxt.system for sending telegrams to the NXT'
from cStringIO import StringIO
from struct import pack, unpack
import nxt.error
class InvalidReplyError(Exception):
pass
class InvalidOpcodeError(Exception):
pass
class Telegram(object):
TYPE = 0 # type byte offset
CODE = 1 # code byte offset
DATA = 2 # data byte offset
TYPE_NOT_DIRECT = 0x01 # system vs. direct type
TYPE_REPLY = 0x02 # reply type (from NXT brick)
TYPE_REPLY_NOT_REQUIRED = 0x80 # reply not required flag
def __init__(self, direct=False, opcode=0, reply_req=True, pkt=None):
self.reply = True
if pkt:
self.pkt = StringIO(pkt)
self.typ = self.parse_u8()
self.opcode = self.parse_u8()
if not self.is_reply():
raise InvalidReplyError
if self.opcode != opcode:
raise InvalidOpcodeError, self.opcode
else:
self.pkt = StringIO()
typ = 0
if not direct:
typ |= Telegram.TYPE_NOT_DIRECT
if not reply_req:
typ |= Telegram.TYPE_REPLY_NOT_REQUIRED
self.reply = False
self.add_u8(typ)
self.add_u8(opcode)
def __str__(self):
return self.pkt.getvalue()
def is_reply(self):
return self.typ == Telegram.TYPE_REPLY
def add_string(self, n_bytes, v):
self.pkt.write(pack('%ds' % n_bytes, v))
def add_filename(self, fname):
self.pkt.write(pack('20s', fname))
def add_s8(self, v):
self.pkt.write(pack('<b', v))
def add_u8(self, v):
self.pkt.write(pack('<B', v))
def add_s16(self, v):
self.pkt.write(pack('<h', v))
def add_u16(self, v):
self.pkt.write(pack('<H', v))
def add_s32(self, v):
self.pkt.write(pack('<i', v))
def add_u32(self, v):
self.pkt.write(pack('<I', v))
def parse_string(self, n_bytes=0):
if n_bytes:
return unpack('%ss' % n_bytes,
self.pkt.read(n_bytes))[0]
else:
return self.pkt.read()
def parse_s8(self):
return unpack('<b', self.pkt.read(1))[0]
def parse_u8(self):
return unpack('<B', self.pkt.read(1))[0]
def parse_s16(self):
return unpack('<h', self.pkt.read(2))[0]
def parse_u16(self):
return unpack('<H', self.pkt.read(2))[0]
def parse_s32(self):
return unpack('<i', self.pkt.read(4))[0]
def parse_u32(self):
return unpack('<I', self.pkt.read(4))[0]
def check_status(self):
nxt.error.check_status(self.parse_u8())
import nxt.direct
import nxt.system
OPCODES = dict(nxt.system.OPCODES)
OPCODES.update(nxt.direct.OPCODES)
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