minecraft.js/lib/tagFormat.js

Minecraft data serialization/deserialization and networking

var Tag = require(__dirname + '/tag.js');

/** @constructor */
var TagFormat = module.exports = function(type, tagId, objId, payload) {
	if(type && typeof type == 'string' &&
	typeof Tag.prototype.types[type.toUpperCase()] != 'undefined' &&
 	typeof tagId != 'undefined') {
 		this.type = Tag.prototype.types[type.toUpperCase()];
		
		if(typeof payload != 'undefined') {
			this.tagId = tagId;
			this.objId = objId;
			if(Array.isArray(payload)) this.payload = payload;
			else if(payload instanceof TagFormat) this.payload = [payload];
			else throw new Error('payload must be a TagFormat or an array of TagFormats');
		} else if(typeof objId != 'undefined') {
			this.tagId = tagId;
			this.objId = objId;
			this.payload = [];
		} else if(typeof tagId != 'undefined') {
			this.tagId = '';
			this.objId = '';
			if(Array.isArray(tagId)) this.payload = tagId;
			else if(tagId instanceof TagFormat) this.payload = [tagId];
			else throw new Error('payload must be a TagFormat or an array of TagFormats');
		}
		
		if(this.type.name == 'List') {
			var tagType;
    		for(var i = 0; i < this.payload.length; i++) {
    			if(!tagType) {
    				tagType = this.payload[i].type.name;
    			} else if(tagType != this.payload[i].type.name) {
    				throw new Error('Payload array members must all be the same type');
    			}
    		}
		}
	} else {
		throw new Error('Invalid argument');
	}
};

TagFormat.prototype.encode = function(data) {		
	var mainTag;
	
	if(this.type.name == 'Compound' || this.type.name == 'List') {
		var subTags = [];
		
		for(var i = 0; i < this.payload.length; i++) {
			var subDataId = this.payload[i].objId;
			var subData = data;
			
			do {
				subData = subData[subDataId.split('.')[0]];
				subDataId = subDataId.substr(subDataId.indexOf('.') + 1);
			} while(subDataId.indexOf('.') > -1);
			
			subTags.push(this.payload[i].encode(subData));
		}
		
		
		mainTag = new Tag(this.type.name, this.tagId, subTags);
	} else {
		mainTag = new Tag(this.type.name, this.tagId, data);
	}		
	
	return mainTag;
};

TagFormat.prototype.decode = function(data) {
	throw new Error('not yet implemented');
};

TagFormat.prototype.append = function(tagFormat) {
	if(this.type.name == 'Compound' || this.type.name == 'List') {
		if(tagFormat instanceof TagFormat) {
			this.payload.push(tagFormat);
		} else if(Array.isArray(tagFormat)) {
			for(var i = 0; i < tagFormat.length; i++) {
				this.payload.push(tagFormat[i]);
			}
		} else {
			throw new Error('Appension must be a TagFormat or an array of TagFormats');
		}
	} else {
		throw new Error('Cannot append to a ' + this.type.name);
	}
	
	return this;
};

TagFormat.prototype.clone = function() {
	var payload = [];
	for(var i = 0; i < this.payload.length; i++) payload.push(this.payload[i]);
	
	return new TagFormat(this.type.name, this.tagId, this.objId, payload || []);
};