source: mainline/tools/xstruct.py@ 4f380d06

#
# Copyright (c) 2008 Martin Decky
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# - Redistributions in binary form must reproduce the above copyright
#   notice, this list of conditions and the following disclaimer in the
#   documentation and/or other materials provided with the distribution.
# - The name of the author may not be used to endorse or promote products
#   derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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#
"""
Convert descriptive structure definitions to structure object
"""

import struct

class Struct:
        def size(self):
                return struct.calcsize(self._format_)
        
        def pack(self):
                args = []
                for variable in self._args_:
                        if (isinstance(self.__dict__[variable], list)):
                                for item in self.__dict__[variable]:
                                        args.append(item)
                        else:
                                args.append(self.__dict__[variable])
                
                return struct.pack(self._format_, *args)

def create(definition):
        "Create structure object"
        
        tokens = definition.split(None)
        
        # Initial byte order tag
        format = {
                "little:":  lambda: "<",
                "big:":     lambda: ">",
                "network:": lambda: "!"
        }[tokens[0]]()
        inst = Struct()
        args = []
        
        # Member tags
        comment = False
        variable = None
        for token in tokens[1:]:
                if (comment):
                        if (token == "*/"):
                                comment = False
                        continue
                
                if (token == "/*"):
                        comment = True
                        continue
                
                if (variable != None):
                        subtokens = token.split("[")
                        
                        if (len(subtokens) > 1):
                                format += "%d" % int(subtokens[1].split("]")[0])
                        
                        format += variable
                        
                        inst.__dict__[subtokens[0]] = None
                        args.append(subtokens[0])
                        
                        variable = None
                        continue
                
                if (token[0:8] == "padding["):
                        size = token[8:].split("]")[0]
                        format += "%dx" % int(size)
                        continue
                
                variable = {
                        "char":     lambda: "s",
                        "uint8_t":  lambda: "B",
                        "uint16_t": lambda: "H",
                        "uint32_t": lambda: "L",
                        "uint64_t": lambda: "Q",
                        
                        "int8_t":   lambda: "b",
                        "int16_t":  lambda: "h",
                        "int32_t":  lambda: "l",
                        "int64_t":  lambda: "q"
                }[token]()
        
        inst.__dict__['_format_'] = format
        inst.__dict__['_args_'] = args
        return inst