1 /*
   2  * Copyright (c) 1995, 2004, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.io;
  27 
  28 /**
  29  * This class allows an application to create an input stream in
  30  * which the bytes read are supplied by the contents of a string.
  31  * Applications can also read bytes from a byte array by using a
  32  * <code>ByteArrayInputStream</code>.
  33  * <p>
  34  * Only the low eight bits of each character in the string are used by
  35  * this class.
  36  *
  37  * @author     Arthur van Hoff
  38  * @see        java.io.ByteArrayInputStream
  39  * @see        java.io.StringReader
  40  * @since      1.0
  41  * @deprecated This class does not properly convert characters into bytes.  As
  42  *             of JDK&nbsp;1.1, the preferred way to create a stream from a
  43  *             string is via the <code>StringReader</code> class.
  44  */
  45 @Deprecated
  46 public
  47 class StringBufferInputStream extends InputStream {
  48     /**
  49      * The string from which bytes are read.
  50      */
  51     protected String buffer;
  52 
  53     /**
  54      * The index of the next character to read from the input stream buffer.
  55      *
  56      * @see        java.io.StringBufferInputStream#buffer
  57      */
  58     protected int pos;
  59 
  60     /**
  61      * The number of valid characters in the input stream buffer.
  62      *
  63      * @see        java.io.StringBufferInputStream#buffer
  64      */
  65     protected int count;
  66 
  67     /**
  68      * Creates a string input stream to read data from the specified string.
  69      *
  70      * @param      s   the underlying input buffer.
  71      */
  72     public StringBufferInputStream(String s) {
  73         this.buffer = s;
  74         count = s.length();
  75     }
  76 
  77     /**
  78      * Reads the next byte of data from this input stream. The value
  79      * byte is returned as an <code>int</code> in the range
  80      * <code>0</code> to <code>255</code>. If no byte is available
  81      * because the end of the stream has been reached, the value
  82      * <code>-1</code> is returned.
  83      * <p>
  84      * The <code>read</code> method of
  85      * <code>StringBufferInputStream</code> cannot block. It returns the
  86      * low eight bits of the next character in this input stream's buffer.
  87      *
  88      * @return     the next byte of data, or <code>-1</code> if the end of the
  89      *             stream is reached.
  90      */
  91     public synchronized int read() {
  92         return (pos < count) ? (buffer.charAt(pos++) & 0xFF) : -1;
  93     }
  94 
  95     /**
  96      * Reads up to <code>len</code> bytes of data from this input stream
  97      * into an array of bytes.
  98      * <p>
  99      * The <code>read</code> method of
 100      * <code>StringBufferInputStream</code> cannot block. It copies the
 101      * low eight bits from the characters in this input stream's buffer into
 102      * the byte array argument.
 103      *
 104      * @param      b     the buffer into which the data is read.
 105      * @param      off   the start offset of the data.
 106      * @param      len   the maximum number of bytes read.
 107      * @return     the total number of bytes read into the buffer, or
 108      *             <code>-1</code> if there is no more data because the end of
 109      *             the stream has been reached.
 110      */
 111     @SuppressWarnings("deprecation")
 112     public synchronized int read(byte[] b, int off, int len) {
 113         if (b == null) {
 114             throw new NullPointerException();
 115         } else if ((off < 0) || (off > b.length) || (len < 0) ||
 116                    ((off + len) > b.length) || ((off + len) < 0)) {
 117             throw new IndexOutOfBoundsException();
 118         }
 119         if (pos >= count) {
 120             return -1;
 121         }
 122 
 123         int avail = count - pos;
 124         if (len > avail) {
 125             len = avail;
 126         }
 127         if (len <= 0) {
 128             return 0;
 129         }
 130         buffer.getBytes(pos, pos + len, b, off);
 131         pos += len;
 132         return len;
 133     }
 134 
 135     /**
 136      * Skips <code>n</code> bytes of input from this input stream. Fewer
 137      * bytes might be skipped if the end of the input stream is reached.
 138      *
 139      * @param      n   the number of bytes to be skipped.
 140      * @return     the actual number of bytes skipped.
 141      */
 142     public synchronized long skip(long n) {
 143         if (n < 0) {
 144             return 0;
 145         }
 146         if (n > count - pos) {
 147             n = count - pos;
 148         }
 149         pos += n;
 150         return n;
 151     }
 152 
 153     /**
 154      * Returns the number of bytes that can be read from the input
 155      * stream without blocking.
 156      *
 157      * @return     the value of <code>count&nbsp;-&nbsp;pos</code>, which is the
 158      *             number of bytes remaining to be read from the input buffer.
 159      */
 160     public synchronized int available() {
 161         return count - pos;
 162     }
 163 
 164     /**
 165      * Resets the input stream to begin reading from the first character
 166      * of this input stream's underlying buffer.
 167      */
 168     public synchronized void reset() {
 169         pos = 0;
 170     }
 171 }