codegen.cpp

/**
	RIGHT TO USE, DISTRIBUTE AND MODIFY
	===================================

	Copyright (C) 2015 Ganesh Prasad Sahoo - All Rights Reserved

	You may use, distribute and modify this code under the Terms 
	of GNU GPL V3 License. You should have received a copy of the
	GNU GPL v3 License with this file. If not please write to
		
		sir.gnsp@gmail.com

	or visit 
	
		http://www.gnu.org/licenses/gpl.txt


*****************************************************************************


	DOCUMENTATION
	=============

	This file contains functions that generate code in Graphviz Dot 
	syntax from the ER Diagram represented in memory. The structure 
	of the representation is described and implemented in structure.hpp .

	The headfile where the void generateCode(const char *outFileName) is
	declared in parser.hpp . This function is a method of the Parser class.


	Important Points
	----------------
	1. 	All nodes of the graph are named as 'node_X' where X is an unique 
		integer. Each unique node has a 32 bit node_no_ associated with it.

	2. 	The code generated is Dot language is targetted towards the Graphviz
		fdp and sfdp engines. The optimal layout of the diagram is possible
		while using the above mentioned engines only.

*/


#include "parser.hpp"
using namespace std;

// For keeping track of numbering/naming of nodes in the generated code.
int nodeCounter=1;


// 
void Parser::generateCode(const char *outFileName){
	ofstream fout;
	fout.open(outFileName);

	fout<<"graph G{maxiter=1000000;overlap=scale;"
		<<"ordering=out;splines=true; label=\""<<diagram_.name_
		<<"\"; node[fontsize=14, fontname=\"Consolas\"];"<<endl
		<<"edge[fontsize=14, fontname=\"Consolas\"];"<<endl;
	
	for(map<string,Entity>::iterator it=entTbl_.table_.begin();
		it!=entTbl_.table_.end(); ++it)
		it->second.printDot(fout);

	for(size_t i=0; i<diagram_.graph_.size(); ++i)
		diagram_.graph_[i].printDot(fout);

	fout<<"}";
	return;
}

void Entity::printDot(ofstream &fout){
	sstream nodeName("node_");
	nodeName<<node_no_;

	fout<<nodeName.str()<<"[shape=box, label=\""<<name_<<"\""
		<<(weak_?",peripheries=2":"")<<"];"<<endl;

	for(size_t i=0; i<attr_.size(); ++i)
		attr_[i].printDot(fout,node_no_);

	return;
}

void Attribute::printDot(ofstream &fout, int parent){
	sstream nodeName("node_");
	sstream parName("node_");
	
	node_no_=nodeCounter++;
	nodeName<<node_no_;
	parName<<parent;

	bool underline = false;
	bool composite = false;
	fout<<nodeName.str()<<"[";
	for(size_t i=0; i<type_.size(); ++i){
		switch(type_[i]){
			case _MULTI:
				fout<<"peripheries=2,";
				break;
			case _COMPOSITE: 
				composite = true;
				break;
			case _KEY:
				underline = true;
				break;
			case _DERIVED:
				fout<<"style=dashed,";
				break;
			default:
				break;
		}
	}
	fout<<"label="<<(underline?"<<u>":"\"")<<name_<<(underline?"</u>>":"\"")
		<<"];"<<endl;

	fout<<nodeName.str()<<"--"<<parName.str()<<";"<<endl;

	if(composite)
		for(size_t i=0; i<attr_.size(); ++i)
			attr_[i].printDot(fout,node_no_);
	
	return;
}

void Relation::printDot(ofstream &fout){
	sstream nodeName("node_");
	nodeName<<node_no_;

	fout<<nodeName.str()<<"[shape=diamond,regular=1,"
		<<(weak_?"peripheries=2,":"")
		<<"label=\""<<name_<<"\"];"<<endl;

	for(size_t i=0; i<from_.size(); ++i)
		from_[i].printDot(fout, node_no_);

	for(size_t i=0; i<to_.size(); ++i)
		to_[i].printDot(fout, node_no_);

	return;
}

void Edge::printDot(ofstream &fout, int parent){
	sstream parName("node_");
	sstream nodeName("node_");

	parName<<parent;
	string n(ent_);
	if(entTbl_.table_.count(n)==1)
		nodeName<<entTbl_.table_[n].node_no_;
	else{
		cout<<"CODE GENERATOR ERROR : Entity "<<ent_
			<<" not defined but used"<<endl;
		return;
	}

	fout<<nodeName.str()<<"--"<<parName.str();
	if(weak_){
		if(complete_){
			if(!normal_){
				if(many_)
					fout<<"[style=dashed, penwidth=4, label=\"N\"];"<<endl;
				else
					fout<<"[style=dashed, penwidth=4, label=\"1\"];"<<endl;
			}
			else fout<<"[style=dashed, penwidth=4];"<<endl;
		}
		else{// fout<<"[style=dashed];"<<endl;
			if(!normal_){
				if(many_)
					fout<<"[style=dashed,label=\"N\"];"<<endl;
				else
					fout<<"[style=dashed,label=\"1\"];"<<endl;
			}
			else fout<<"[style=dashed];"<<endl;
		}
	}
	else{
		if(complete_){
			if(!normal_){
				if(many_)
					fout<<"[penwidth=4, label=\"N\"];"<<endl;
				else
					fout<<"[penwidth=4, label=\"1\"];"<<endl;
			}
			else fout<<"[penwidth=4];"<<endl;
		}
		else{// fout<<";"<<endl;
			if(!normal_){
				if(many_)
					fout<<"[label=\"N\"];"<<endl;
				else
					fout<<"[label=\"1\"];"<<endl;
			}
			else fout<<";"<<endl;
		}
	}
	return;
}