src/MessageImprint.js

import * as asn1js from "asn1js";
import { getParametersValue, clearProps } from "pvutils";
import AlgorithmIdentifier from "./AlgorithmIdentifier.js";
//**************************************************************************************
/**
 * Class from RFC3161
 */
export default class MessageImprint
{
	//**********************************************************************************
	/**
	 * Constructor for MessageImprint class
	 * @param {Object} [parameters={}]
	 * @property {Object} [schema] asn1js parsed value
	 */
	constructor(parameters = {})
	{
		//region Internal properties of the object
		/**
		 * @type {AlgorithmIdentifier}
		 * @description hashAlgorithm
		 */
		this.hashAlgorithm = getParametersValue(parameters, "hashAlgorithm", MessageImprint.defaultValues("hashAlgorithm"));
		/**
		 * @type {OctetString}
		 * @description hashedMessage
		 */
		this.hashedMessage = getParametersValue(parameters, "hashedMessage", MessageImprint.defaultValues("hashedMessage"));
		//endregion

		//region If input argument array contains "schema" for this object
		if("schema" in parameters)
			this.fromSchema(parameters.schema);
		//endregion
	}
	//**********************************************************************************
	/**
	 * Return default values for all class members
	 * @param {string} memberName String name for a class member
	 */
	static defaultValues(memberName)
	{
		switch(memberName)
		{
			case "hashAlgorithm":
				return new AlgorithmIdentifier();
			case "hashedMessage":
				return new asn1js.OctetString();
			default:
				throw new Error(`Invalid member name for MessageImprint class: ${memberName}`);
		}
	}
	//**********************************************************************************
	/**
	 * Compare values with default values for all class members
	 * @param {string} memberName String name for a class member
	 * @param {*} memberValue Value to compare with default value
	 */
	static compareWithDefault(memberName, memberValue)
	{
		switch(memberName)
		{
			case "hashAlgorithm":
				return ((memberValue.algorithmId === "") && (("algorithmParams" in memberValue) === false));
			case "hashedMessage":
				return (memberValue.isEqual(MessageImprint.defaultValues(memberName)) === 0);
			default:
				throw new Error(`Invalid member name for MessageImprint class: ${memberName}`);
		}
	}
	//**********************************************************************************
	/**
	 * Return value of asn1js schema for current class
	 * @param {Object} parameters Input parameters for the schema
	 * @returns {Object} asn1js schema object
	 */
	static schema(parameters = {})
	{
		//MessageImprint ::= SEQUENCE  {
		//    hashAlgorithm                AlgorithmIdentifier,
		//    hashedMessage                OCTET STRING  }

		/**
		 * @type {Object}
		 * @property {string} [blockName]
		 * @property {string} [hashAlgorithm]
		 * @property {string} [hashedMessage]
		 */
		const names = getParametersValue(parameters, "names", {});

		return (new asn1js.Sequence({
			name: (names.blockName || ""),
			value: [
				AlgorithmIdentifier.schema(names.hashAlgorithm || {}),
				new asn1js.OctetString({ name: (names.hashedMessage || "") })
			]
		}));
	}
	//**********************************************************************************
	/**
	 * Convert parsed asn1js object into current class
	 * @param {!Object} schema
	 */
	fromSchema(schema)
	{
		//region Clear input data first
		clearProps(schema, [
			"hashAlgorithm",
			"hashedMessage"
		]);
		//endregion
		
		//region Check the schema is valid
		const asn1 = asn1js.compareSchema(schema,
			schema,
			MessageImprint.schema({
				names: {
					hashAlgorithm: {
						names: {
							blockName: "hashAlgorithm"
						}
					},
					hashedMessage: "hashedMessage"
				}
			})
		);

		if(asn1.verified === false)
			throw new Error("Object's schema was not verified against input data for MessageImprint");
		//endregion

		//region Get internal properties from parsed schema
		this.hashAlgorithm = new AlgorithmIdentifier({ schema: asn1.result.hashAlgorithm });
		this.hashedMessage = asn1.result.hashedMessage;
		//endregion
	}
	//**********************************************************************************
	/**
	 * Convert current object to asn1js object and set correct values
	 * @returns {Object} asn1js object
	 */
	toSchema()
	{
		//region Construct and return new ASN.1 schema for this object
		return (new asn1js.Sequence({
			value: [
				this.hashAlgorithm.toSchema(),
				this.hashedMessage
			]
		}));
		//endregion
	}
	//**********************************************************************************
	/**
	 * Convertion for the class to JSON object
	 * @returns {Object}
	 */
	toJSON()
	{
		return {
			hashAlgorithm: this.hashAlgorithm.toJSON(),
			hashedMessage: this.hashedMessage.toJSON()
		};
	}
	//**********************************************************************************
}
//**************************************************************************************