src/DigestInfo.js

import * as asn1js from "asn1js";
import { getParametersValue, clearProps } from "pvutils";
import AlgorithmIdentifier from "./AlgorithmIdentifier.js";
//**************************************************************************************
/**
 * Class from RFC3447
 */
export default class DigestInfo 
{
	//**********************************************************************************
	/**
	 * Constructor for DigestInfo class
	 * @param {Object} [parameters={}]
	 * @property {Object} [schema] asn1js parsed value
	 */
	constructor(parameters = {})
	{
		//region Internal properties of the object
		/**
		 * @type {AlgorithmIdentifier}
		 * @description digestAlgorithm
		 */
		this.digestAlgorithm = getParametersValue(parameters, "digestAlgorithm", DigestInfo.defaultValues("digestAlgorithm"));
		/**
		 * @type {OctetString}
		 * @description digest
		 */
		this.digest = getParametersValue(parameters, "digest", DigestInfo.defaultValues("digest"));
		//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 "digestAlgorithm":
				return new AlgorithmIdentifier();
			case "digest":
				return new asn1js.OctetString();
			default:
				throw new Error(`Invalid member name for DigestInfo 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 "digestAlgorithm":
				return ((AlgorithmIdentifier.compareWithDefault("algorithmId", memberValue.algorithmId)) &&
				(("algorithmParams" in memberValue) === false));
			case "digest":
				return (memberValue.isEqual(DigestInfo.defaultValues(memberName)));
			default:
				throw new Error(`Invalid member name for DigestInfo 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 = {})
	{
		//DigestInfo ::= SEQUENCE {
		//    digestAlgorithm DigestAlgorithmIdentifier,
		//    digest Digest }
		
		//Digest ::= OCTET STRING
		
		/**
		 * @type {Object}
		 * @property {string} [blockName]
		 * @property {string} [type]
		 * @property {string} [setName]
		 * @property {string} [values]
		 */
		const names = getParametersValue(parameters, "names", {});
		
		return (new asn1js.Sequence({
			name: (names.blockName || ""),
			value: [
				AlgorithmIdentifier.schema(names.digestAlgorithm || {
					names: {
						blockName: "digestAlgorithm"
					}
				}),
				new asn1js.OctetString({ name: (names.digest || "digest") })
			]
		}));
	}
	//**********************************************************************************
	/**
	 * Convert parsed asn1js object into current class
	 * @param {!Object} schema
	 */
	fromSchema(schema)
	{
		//region Clear input data first
		clearProps(schema, [
			"digestAlgorithm",
			"digest"
		]);
		//endregion
		
		//region Check the schema is valid
		const asn1 = asn1js.compareSchema(schema,
			schema,
			DigestInfo.schema({
				names: {
					digestAlgorithm: {
						names: {
							blockName: "digestAlgorithm"
						}
					},
					digest: "digest"
				}
			})
		);
		
		if(asn1.verified === false)
			throw new Error("Object's schema was not verified against input data for DigestInfo");
		//endregion
		
		//region Get internal properties from parsed schema
		this.digestAlgorithm = new AlgorithmIdentifier({ schema: asn1.result.digestAlgorithm });
		this.digest = asn1.result.digest;
		//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.digestAlgorithm.toSchema(),
				this.digest
			]
		}));
		//endregion
	}
	//**********************************************************************************
	/**
	 * Convertion for the class to JSON object
	 * @returns {Object}
	 */
	toJSON()
	{
		return {
			digestAlgorithm: this.digestAlgorithm.toJSON(),
			digest: this.digest.toJSON()
		};
	}
	//**********************************************************************************
}
//**************************************************************************************