XML Game Engine - game.cpp

// game.cpp
// XML Game Engine
// author: beefviper
// date: May 21, 2020

// Wrote some helper functions
// Looks better than the first attempt: https://pastebin.com/DJYFV715

#include "game.h"

void xge::Game::init(std::string filename)
{
    tx::XMLError xmlLoadFile = xml.LoadFile(filename.c_str());
    checkXMLResult(xmlLoadFile);

    tx::XMLElement* xGame = getXMLElement(xml.FirstChildElement("game"));
    tx::XMLElement* xHead = getXMLElement(xGame, "head");
    tx::XMLElement* xTitle = getXMLElement(xHead,"title");
    tx::XMLElement* xScreen = getXMLElement(xHead,"screen");
    tx::XMLElement* xBody = getXMLElement(xGame,"body");
    tx::XMLElement* xObjects = getXMLElement(xBody, "objects");
    tx::XMLElement* xStates = getXMLElement(xBody, "states");

    title = getXMLText(xTitle);
    width = getXMLAttributeInt(xScreen, "width");
    height = getXMLAttributeInt(xScreen, "height");

    std::cout << "title = " << title << std::endl;
    std::cout << "screen.width = " << width << std::endl;
    std::cout << "screen.height = " << height << std::endl;
}

void xge::Game::checkXMLResult(tx::XMLError result)
{
    if (result != tx::XML_SUCCESS)
    {
        std::cout << xml.ErrorStr() << std::endl;
        exit(EXIT_FAILURE);
    }
}

tx::XMLElement* xge::Game::getXMLElement(tx::XMLElement* element, std::string tag)
{
    tx::XMLElement* newElement = nullptr;
    newElement = tag.size() ? element->FirstChildElement(tag.c_str()) : element;

    if (newElement == nullptr)
    {
        std::cout << "Error: parsing <" << (tag.size() ? tag : "game") << ">"  << std::endl;
        exit(EXIT_FAILURE);
    }

    return newElement;
}

std::string xge::Game::getXMLText(tx::XMLElement* element)
{
    return (element->GetText() ? element->GetText() : "");
}

std::string xge::Game::getXMLAttribute(tx::XMLElement* element, std::string attribute)
{
    const char* attributeText = nullptr;

    attributeText = element->Attribute(attribute.c_str());
    if (attributeText == nullptr)
    {
        std::cout << "Error: finding <" << element->Name() << "> attribute \"" << attribute << "\"" << std::endl;
        exit(EXIT_FAILURE);
    }

    std::string attributeString = attributeText;

    return attributeString;
}

int xge::Game::getXMLAttributeInt(tx::XMLElement* element, std::string attribute)
{
    int attributeInt{};

    tx::XMLError xError = element->QueryIntAttribute(attribute.c_str(), &attributeInt);
    if (xError != tx::XML_SUCCESS )
    {
        std::cout << "Error: parsing <" << element->Name() << "> int attribute \"" << attribute << "\"" << std::endl;
        exit(EXIT_FAILURE);
    }

    return  attributeInt;
}