root/projects/2008/pyogp/pyogp.lib.base/trunk/pyogp/lib/base/message/data_packer.py

# standrad python libraries
import struct

# pyogp
from pyogp.lib.base.datatypes import UUID, Vector3, Quaternion

# pyogp messaging
from types import MsgType, EndianType

class DataPacker(object):
    def __init__(self):
        self.packer = {}
        self.packer[MsgType.MVT_FIXED]          = ('>',self.__pack_string)  #:DE 23oct2008 added handler for MVT_FIXED
        self.packer[MsgType.MVT_VARIABLE]       = ('>',self.__pack_string)
        self.packer[MsgType.MVT_S8]             = ('>','b')
        self.packer[MsgType.MVT_U8]             = ('>','B')
        self.packer[MsgType.MVT_BOOL]           = ('>','B')
        self.packer[MsgType.MVT_LLUUID]         = ('>',self.__pack_uuid)
        self.packer[MsgType.MVT_IP_ADDR]        = ('>',self.__pack_string)
        self.packer[MsgType.MVT_IP_PORT]        = ('>','H')
        self.packer[MsgType.MVT_U16]            = ('<','H')
        self.packer[MsgType.MVT_U32]            = ('<','I')
        self.packer[MsgType.MVT_U64]            = ('<','Q')
        self.packer[MsgType.MVT_S16]            = ('<','h')
        self.packer[MsgType.MVT_S32]            = ('<','i')
        self.packer[MsgType.MVT_S64]            = ('<','q')
        self.packer[MsgType.MVT_F32]            = ('<','f')
        self.packer[MsgType.MVT_F64]            = ('<','d')
        self.packer[MsgType.MVT_LLVector3]      = ('<',self.__pack_vector3)
        self.packer[MsgType.MVT_LLVector3d]     = ('<',self.__pack_vector3d)
        self.packer[MsgType.MVT_LLVector4]      = ('<',self.__pack_vector4)
        self.packer[MsgType.MVT_LLQuaternion]   = ('<',self.__pack_quat)

    def pack_data(self, data, data_type, endian_type=EndianType.NONE):
        if data_type in self.packer:
            endian, pack = self.packer[data_type]

            #override endian            
            if endian_type != EndianType.NONE:
                endian = endian_type

            if callable(pack):
                return pack(endian, data)
            else:
                return struct.pack(endian + pack, data)

        return None

    def __pack_tuple(self, endian, tup, tp):
        size = len(tup)
        return struct.pack(endian + str(size) + tp, *tup)

    def __pack_vector3(self, endian, vec):        
        if isinstance(vec, Vector3):
            vec = vec() # convert to tuple
        return self.__pack_tuple(endian, vec, 'f')

    def __pack_vector3d(self, endian, vec):
        return self.__pack_tuple(endian, vec, 'd')

    def __pack_vector4(self, endian, vec):
        return self.__pack_tuple(endian, vec, 'f')

    def __pack_quat(self, endian, quat):
        #first, pack to vector3
        #vec = quat_to_vec3(quat)
        return self.__pack_vector3(endian, quat)

    def __pack_uuid(self, endian, uuid):

        if isinstance(uuid, UUID):
            return uuid.get_bytes()
        else:
            return uuid.bytes

    def __pack_string(self, endian, pack_string):
        """Return the string UTF-8 encoded and null terminated."""
        if pack_string == None:
            return '\x00'
        elif isinstance(pack_string,unicode):
            return pack_string.encode('utf-8') + '\x00'
        else:
            return pack_string + '\x00'

"""
Contributors can be viewed at:
http://svn.secondlife.com/svn/linden/projects/2008/pyogp/CONTRIBUTORS.txt 

$LicenseInfo:firstyear=2008&license=apachev2$

Copyright 2009, Linden Research, Inc.

Licensed under the Apache License, Version 2.0 (the "License").
You may obtain a copy of the License at:
    http://www.apache.org/licenses/LICENSE-2.0
or in 
    http://svn.secondlife.com/svn/linden/projects/2008/pyogp/LICENSE.txt

$/LicenseInfo$
"""