001/* 002 * jPOS Project [http://jpos.org] 003 * Copyright (C) 2000-2023 jPOS Software SRL 004 * 005 * This program is free software: you can redistribute it and/or modify 006 * it under the terms of the GNU Affero General Public License as 007 * published by the Free Software Foundation, either version 3 of the 008 * License, or (at your option) any later version. 009 * 010 * This program is distributed in the hope that it will be useful, 011 * but WITHOUT ANY WARRANTY; without even the implied warranty of 012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 013 * GNU Affero General Public License for more details. 014 * 015 * You should have received a copy of the GNU Affero General Public License 016 * along with this program. If not, see <http://www.gnu.org/licenses/>. 017 */ 018 019package org.jpos.iso; 020 021 022/** 023 * This interface is used to encode and decode length prefixes. 024 * 025 * @author joconnor 026 * @version $Revision$ $Date$ 027 */ 028public interface Prefixer 029{ 030 /** 031 * Fills a byte array with the field length data in raw form. 032 * 033 * @param length 034 * The length to be encoded. 035 * @param b 036 * The byte array to fill with the encoded length. 037 */ 038 void encodeLength(int length, byte[] b) throws ISOException; 039 040 /** 041 * Decodes an encoded length. 042 * 043 * @param b 044 * The byte array to scan for the length. 045 * @param offset 046 * The offset to start scanning from. 047 * @return The length in chars of the field data to follow this 048 * LengthPrefix. 049 */ 050 int decodeLength(byte[] b, int offset) throws ISOException; 051 052 /** 053 * Returns the number of bytes taken up by the length encoding. 054 */ 055 int getPackedLength(); 056}