replacer.cpp

/*
This file has the implementation of the replacer class functions
*/

#include "replacer.h"
#include<iostream>
#include<fstream>
#include<string>
#include<unordered_map>
using namespace std;

//constructor
replacer::replacer()
{
    language = "en";                                                    //Initializes language to English
    preserveUnmatched = "false";                                        //Initializes preserveUnmatched to false
}

//function to replace the placeholders "${namespace:key}"
void replacer::nestedReplace(string& param, int index)
{
    unordered_map<string,string>  m1;
    string line,fileName,key;
    size_t index1,index2;
    m1.clear();                                                         //clear the map

    index1 = param.find(':',index+2);
    if(index1 != string::npos)
    {

        //if place holders is in "${namespace:${string}} ${namespace:key}" pattern
        if((index1 > param.find('$',index+2)))
        {
            return;
        }
        //for nested replacements of the placeholders
        if((param[index1+1]== '$') && (param[index1+2]=='{'))
        {
            nestedReplace(param,index1+1);
        }

        index2 = param.find('}', index1);
        if(index2 != string::npos)
        {
            //get the values from the variables file to replace with placeholders
            fileName = param.substr(index+2,index1-index-2);                    //extracts the namespace value from the placeholder  to get the variables file name.
            ifs.open(language + "\/" + fileName + ".properties");               //opens the file from the respective path based on the language eg: en/colors.properties
            while (ifs >> line)
            {
                //stores the key and value from the variables file in the map
                size_t equal = line.find("=");
                string key = line.substr(0, equal);
                string value = line.substr(equal + 1);
                m1[key] = value;
            }

            //Match the keys to replace in the string

            key = param.substr(index1+1,index2-index1-1);                       //extracts the key from the placeholder
            if(m1.find(key) == m1.end())
            {
                //for unmatched keys
                if(preserveUnmatched == "false")
                    param.replace(index, index2 - index+1, " ");
            }
            else
            {
                param.replace(index, index2 - index+1, m1[key]);
            }
            ifs.close();
        }
    }
}


void replacer::multipleReplace(string& parameters)
{
	size_t index = parameters.find("$");

	//parse the string to replace all the placeholders
	while (index != string::npos)
	{
		if (parameters[index + 1] == '{')
		{
		    nestedReplace(parameters,index);
        }
		index = parameters.find("$",index+1);                        //get the next placeholder
	}

	cout<<"\n"<<parameters<<"\n"<<endl;                                          //prints the replaced string.


}