1 /* StringBufferInputStream.java -- Read an String as a stream 2 Copyright (C) 1998, 1999, 2001 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., 59 Temple Place, Suite 330, Boston, MA 19 02111-1307 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 java.io; 40 41 /* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3 42 * "The Java Language Specification", ISBN 0-201-63451-1 43 * plus online API docs for JDK 1.2 beta from http://www.javasoft.com. 44 * Status: Believed complete and correct. Deprecated in JDK 1.1. 45 */ 46 47 /** 48 * This class permits a <code>String</code> to be read as an input stream. 49 * The low eight bits of each character in the <code>String</code> are the 50 * bytes that are returned. The high eight bits of each character are 51 * discarded. 52 * <p> 53 * The mark/reset functionality in this class behaves differently than 54 * normal. The <code>mark()</code> method is always ignored and the 55 * <code>reset()</code> method always resets in stream to start reading from 56 * position 0 in the String. Note that since this method does not override 57 * <code>markSupported()</code> in <code>InputStream</code>, calling that 58 * method will return <code>false</code>. 59 * <p> 60 * Note that this class is deprecated because it does not properly handle 61 * 16-bit Java characters. It is provided for backwards compatibility only 62 * and should not be used for new development. The <code>StringReader</code> 63 * class should be used instead. 64 * 65 * @deprecated 66 * 67 * @author Aaron M. Renn (arenn@urbanophile.com) 68 * @author Warren Levy <warrenl@cygnus.com> 69 */ 70 public class StringBufferInputStream extends InputStream 71 { 72 /** The String which is the input to this stream. */ 73 protected String buffer; 74 75 /** Position of the next byte in buffer to be read. */ 76 protected int pos = 0; 77 78 /** The length of the String buffer. */ 79 protected int count; 80 81 /** 82 * Create a new <code>StringBufferInputStream</code> that will read bytes 83 * from the passed in <code>String</code>. This stream will read from the 84 * beginning to the end of the <code>String</code>. 85 * 86 * @param s The <code>String</code> this stream will read from. 87 */ StringBufferInputStream(String s)88 public StringBufferInputStream(String s) 89 { 90 buffer = s; 91 count = s.length(); 92 } 93 94 /** 95 * This method returns the number of bytes available to be read from this 96 * stream. The value returned will be equal to <code>count - pos</code>. 97 * 98 * @return The number of bytes that can be read from this stream before 99 * blocking, which is all of them 100 */ available()101 public int available() 102 { 103 return count - pos; 104 } 105 106 /** 107 * This method reads one byte from the stream. The <code>pos</code> counter 108 * is advanced to the next byte to be read. The byte read is returned as 109 * an int in the range of 0-255. If the stream position is already at the 110 * end of the buffer, no byte is read and a -1 is returned in order to 111 * indicate the end of the stream. 112 * 113 * @return The byte read, or -1 if end of stream 114 */ read()115 public int read() 116 { 117 if (pos >= count) 118 return -1; // EOF 119 120 return ((int) buffer.charAt(pos++)) & 0xFF; 121 } 122 123 /** 124 * This method reads bytes from the stream and stores them into a caller 125 * supplied buffer. It starts storing the data at index <code>offset</code> 126 * into the buffer and attempts to read <code>len</code> bytes. This method 127 * can return before reading the number of bytes requested if the end of the 128 * stream is encountered first. The actual number of bytes read is 129 * returned. If no bytes can be read because the stream is already at 130 * the end of stream position, a -1 is returned. 131 * <p> 132 * This method does not block. 133 * 134 * @param b The array into which the bytes read should be stored. 135 * @param off The offset into the array to start storing bytes 136 * @param len The requested number of bytes to read 137 * 138 * @return The actual number of bytes read, or -1 if end of stream. 139 */ read(byte[] b, int off, int len)140 public int read(byte[] b, int off, int len) 141 { 142 if (off < 0 || len < 0 || off + len > b.length) 143 throw new ArrayIndexOutOfBoundsException(); 144 145 if (pos >= count) 146 return -1; // EOF 147 148 int numRead = Math.min(len, count - pos); 149 if (numRead < 0) 150 return 0; 151 152 buffer.getBytes(pos, pos + numRead, b, off); 153 pos += numRead; 154 return numRead; 155 } 156 157 /** 158 * This method sets the read position in the stream to the beginning 159 * setting the <code>pos</code> variable equal to 0. Note that this differs 160 * from the common implementation of the <code>reset()</code> method. 161 */ reset()162 public void reset() 163 { 164 pos = 0; 165 } 166 167 /** 168 * This method attempts to skip the requested number of bytes in the 169 * input stream. It does this by advancing the <code>pos</code> value by the 170 * specified number of bytes. It this would exceed the length of the 171 * buffer, then only enough bytes are skipped to position the stream at 172 * the end of the buffer. The actual number of bytes skipped is returned. 173 * 174 * @param n The requested number of bytes to skip 175 * 176 * @return The actual number of bytes skipped. 177 */ skip(long n)178 public long skip(long n) 179 { 180 if (n < 0) 181 return 0L; 182 183 long actualSkip = Math.min(n, count - pos); 184 pos += actualSkip; 185 return actualSkip; 186 } 187 } 188