structure.py

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"""
Created on Nov 22, 2014

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@author: Dula Nad
"""

from .variable import Variable
from .enum import Enum

class Structure:
    """
    Represents the C++ data structure in the object form.
    
    Class attributes:
    _XMLTAG -- constant string with the xml tag description
    """
    _XMLTAG = 'struct'
    
    class VarGroup:
        """
        Represents a variable group inside the structure object.
    
        Class attributes:
        _XMLTAG -- constant string with the xml tag description
        """
        _XMLTAG = 'group'
        
        def __init__(self, xmlnode = None):
            """
            Populates the structure from a XML node info.
            When the XML node is not defined, does nothing.
        
            xmlnode -- the XML node with the member definition 
        
            Instance attributes:
            gvariables -- the member variables list
            gcond -- the group conditional
            """
            self.gcond = None
         
            if xmlnode != None: self.from_xml(xmlnode) 
            
        def from_xml(self, xmlnode):
            """
            Extracts the group attributes from the XML node.
            Memeber variables are extracted from the child 
            nodes as well.
        
            xmlnode -- the XML node with the member definition
            """
        
            if xmlnode.tag != self._XMLTAG:
                raise NameError(self.__class__.__name__ +
                                ' expected XML tag: "' + 
                                self._XMLTAG + 
                                '"')
            
            self.gcond = xmlnode.get('if', self.gcond)
                   
            for node in xmlnode.findall(Variable._XMLTAG):
                self.gvariables.append(Variable(node))
        

    def __init__(self, xmlnode = None):
        """
        Populates the structure from a XML node info.
        When the XML node is not defined, does nothing.
        
        xmlnode -- the XML node with the member definition 
        
        Instance attributes:
        sname    -- name of the structure
        sinherit -- the class that is inherited
        svariables -- the direct member variables list
        sgroups -- the grouped member variables list
        smethods -- the member methods list
        senums -- the enumerations list
        sassert_size -- add size assertion in bytes (useful for bitfields)
        sserialization -- the type of serialization (defaults to object serializable)
        sid -- the numeric id constant (useful for command structs)
        """
        self.sname = 'Unnamed'
        self.sinherit = None
        self.svariables = []
        self.sgroups = []
        self.smethods = []
        self.stypedefs = []  
        self.senums = []
        self.sassert_size = None  
        self.sserialization = 'object_serializable'
         
        if xmlnode != None: self.from_xml(xmlnode)  
        
    def from_xml(self, xmlnode):
        """
        Extracts the structure attributes from the XML node.
        Memeber variables and functions are extracted from the 
        child nodes as well.
        
        xmlnode -- the XML node with the member definition
        """
        
        if xmlnode.tag != self._XMLTAG:
            raise NameError(self.__class__.__name__ +
                            ' expected XML tag: "' + 
                            self._XMLTAG + 
                            '"')
        
        self.sname = xmlnode.get('name', self.sname)
        self.sinherit = xmlnode.get('inherit', self.sinherit)
        self.sassert_size = xmlnode.get('assert_size', self.sassert_size)
        self.sserialization = xmlnode.get('serialization', self.sserialization)
        
        for node in xmlnode.findall('.//'+Variable._XMLTAG):
            self.svariables.append(Variable(node))
        
        for node in xmlnode.findall(Enum._XMLTAG):
            self.senums.append(Enum(node))
        
    def gen_code(self, bindent = '', indent = '  '):
        """
        Generates the full structure definition C++ code and
        returns it as a string.
        
        bindent -- the current indent in the document
        indent -- the usual minimum indentation
        """
        code = bindent + indent + 'struct ' + self.sname
        if self.sinherit != None:
            code = code + ': public ' + self.sinherit
        
        code = code + '\n{\n'
        
        for t in self.stypedefs:
            code = code + 'typedef ' + t[0] + ' ' + t[1] + ';\n' 
        
        for enum in self.senums:
            code = code + enum.gen_code() + '\n'
            
        if len(self.senums): code = code + '\n'
            
        for method in self.smethods:
            code = code + method.gen_code() + '\n'
            
        for var in self.svariables:
            code = code + var.gen_code() + '\n'
            
        code = code + '};\n'  
            
        if self.sassert_size != None:
            code = code + ('BOOST_STATIC_ASSERT((sizeof(' + self.sname +') == ' + 
                self.sassert_size + ')' + ' && ("' + self.sname + 
                ' structure is assumed as size ' + self.sassert_size + 
                ' bytes."));\n')
                    
        return code  
    
    def gen_impl(self, bindent = '', indent = '  '):
        """
        Generates the method implementations in C++ code and
        returns it as a string.
        
        bindent -- the current indent in the document
        indent -- the usual minimum indentation
        """ 
        code = ''         
        for method in self.smethods:
            code = code + method.gen_impl(namespace=self.sname) + '\n'
                    
        return code  
        
    def __str__(self):
        """
        Overriden string specifier returns the C++ code snippet 
        without indentation.
        """
        return self.gen_code(indent = '')