AppsByDownloadCountTree.cpp

/****************************************************************************/
/*                                                                          */
/* AppsByDownloadCountTree class implementation                             */
/*                                                                          */
/****************************************************************************/

#include <cstdlib>                          // NULL definition
#include "AppsByDownloadCountTree.h"
#include "AVLTree.h"
#include "common.h"


void AppsByDownloadCountTree::addApp(const AppsListIterator& appData) {
	// This function is basically an alias to AVLTree::insert()

	// Create a DownloadCountAndId to be used as key
	DownloadCountAndId key(appData->appId, appData->downloadCount);
	insert(key, appData);
}

void AppsByDownloadCountTree::removeApp(int downloadCount, int appId) {
	// This function is basically an alias to AVLTree::remove()

	// Create a DownloadCountAndId to be used as key
	DownloadCountAndId key(appId, downloadCount);
	remove(key);
}


int AppsByDownloadCountTree::predKeyData(const DownloadCountAndId& key,
		const AppsListIterator& data) const {

	// Compare an appId with an AppData pointer:
	// Simply compare the given appId with the appId in the structure
	// pointed by data.

	if (key.downloadCount < data->downloadCount) {
		return -1;
	} else if (key.downloadCount > data->downloadCount) {
		return 1;
	}

	// Equal downloadCount, sort using appId
	// NOTE: Lower appId is considered larger value here, to match instructions
	// in FAQ and PDF about finding the top app
	if (data->appId < key.appId) {
		return -1;
	} else if (data->appId > key.appId) {
		return 1;
	}

	// Equal downloadCount and appId
	// NOTE: This should not be possible as appId is unique
	return 0;
}

int AppsByDownloadCountTree::predDataData(const AppsListIterator& data,
		const AppsListIterator& other) const {

	if (data->downloadCount < other->downloadCount) {
		return -1;
	} else if (data->downloadCount > other->downloadCount) {
		return 1;
	}

	// Equal downloadCount, sort using appId
	// NOTE: Lower appId is considered larger value here, to match instructions
	// in FAQ and PDF about finding the top app
	if (other->appId < data->appId) {
		return -1;
	} else if (other->appId > data->appId) {
		return 1;
	}

	// Equal downloadCount and appId
	// NOTE: This should not be possible as appId is unique
	return 0;
}