1 /* AligningInput.java -- 2 Copyright (C) 2005 Free Software Foundation, Inc. 3 4 This file is part of GNU Classpath. 5 6 GNU Classpath is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 GNU Classpath is distributed in the hope that it will be useful, but 12 WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GNU Classpath; see the file COPYING. If not, write to the 18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19 02110-1301 USA. 20 21 Linking this library statically or dynamically with other modules is 22 making a combined work based on this library. Thus, the terms and 23 conditions of the GNU General Public License cover the whole 24 combination. 25 26 As a special exception, the copyright holders of this library give you 27 permission to link this library with independent modules to produce an 28 executable, regardless of the license terms of these independent 29 modules, and to copy and distribute the resulting executable under 30 terms of your choice, provided that you also meet, for each linked 31 independent module, the terms and conditions of the license of that 32 module. An independent module is a module which is not derived from 33 or based on this library. If you modify this library, you may extend 34 this exception to your version of the library, but you are not 35 obligated to do so. If you do not wish to do so, delete this 36 exception statement from your version. */ 37 38 39 package gnu.CORBA.CDR; 40 41 import java.io.ByteArrayInputStream; 42 43 import org.omg.CORBA.BAD_PARAM; 44 45 /** 46 * The input stream with the possibility to align on the 47 * word (arbitrary size) boundary. 48 * 49 * @author Audrius Meskauskas (AudriusA@Bioinformatics.org) 50 */ 51 public class AligningInput 52 extends ByteArrayInputStream 53 { 54 /** 55 * The alignment offset. 56 */ 57 private int offset = 0; 58 59 /** 60 * Create a stream, reading form the given buffer. 61 * 62 * @param a_buffer a buffer to read from. 63 */ AligningInput(byte[] a_buffer)64 public AligningInput(byte[] a_buffer) 65 { 66 super(a_buffer); 67 } 68 69 /** 70 * Set the alignment offset, if the index of the first byte in the 71 * stream is different from 0. 72 */ setOffset(int an_offset)73 public void setOffset(int an_offset) 74 { 75 offset = an_offset; 76 } 77 78 /** 79 * Skip several bytes, aligning the internal pointer on the 80 * selected boundary. 81 * 82 * @throws BAD_PARAM, minor code 0, the alignment is not possible, 83 * usually due the wrong parameter value. 84 */ align(int alignment)85 public void align(int alignment) 86 { 87 try 88 { 89 int d = (pos + offset) % alignment; 90 if (d > 0) 91 { 92 skip(alignment - d); 93 } 94 } 95 catch (Exception ex) 96 { 97 BAD_PARAM p = new BAD_PARAM("Unable to align at " + alignment); 98 p.initCause(ex); 99 throw p; 100 } 101 } 102 103 /** 104 * Get the byte buffer, from where the data are read. 105 */ getBuffer()106 public byte[] getBuffer() 107 { 108 return buf; 109 } 110 111 /** 112 * Get the current position in the buffer. 113 * 114 * @return The position in the buffer, taking offset into consideration. 115 */ getPosition()116 public int getPosition() 117 { 118 return pos + offset; 119 } 120 121 /** 122 * Jump to the given position, taking offset into consideration. 123 */ seek(int position)124 public void seek(int position) 125 { 126 if (position < offset || position > (count+offset)) 127 throw new ArrayIndexOutOfBoundsException(position 128 + " is out of valid ["+offset+".." + (count+offset) + "[ range"); 129 pos = position - offset; 130 } 131 } 132