114 lines
2.7 KiB
Java
114 lines
2.7 KiB
Java
/* Copyright (C) 1998, 1999 Cygnus Solutions
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This file is part of libgcj.
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This software is copyrighted work licensed under the terms of the
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Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
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details. */
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package java.io;
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/**
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* @author Warren Levy <warrenl@cygnus.com>
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* @date October 7, 1998.
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*/
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/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
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* "The Java Language Specification", ISBN 0-201-63451-1
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* plus online API docs for JDK 1.2 beta from http://www.javasoft.com.
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* Status: Believed complete and correct
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*/
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public class ByteArrayInputStream extends InputStream
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{
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/* An array of bytes provided by the creator of the stream. */
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protected byte[] buf;
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/* Position of the next byte in buf to be read. */
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protected int pos;
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/* The currently marked position in the stream. */
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protected int mark;
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/* The index in buf one greater than the last valid character. */
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protected int count;
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public ByteArrayInputStream(byte[] buffer)
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{
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this(buffer, 0, buffer.length);
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}
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public ByteArrayInputStream(byte[] buffer, int offset, int length)
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{
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buf = buffer;
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count = offset + length;
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if (count > buf.length)
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count = buf.length;
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pos = offset;
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// TBD: What should we do if pos is neg. or > count? E.g. throw exc. or:
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// if (pos < 0 || pos > count)
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// pos = 0;
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mark = pos;
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}
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public synchronized int available()
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{
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return count - pos;
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}
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public synchronized void mark(int readAheadLimit)
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{
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// readAheadLimit is ignored per Java Class Lib. book, p.220.
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mark = pos;
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}
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public boolean markSupported()
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{
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return true;
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}
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public synchronized int read()
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{
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if (pos < 0)
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throw new ArrayIndexOutOfBoundsException(pos);
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if (pos < count)
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return ((int) buf[pos++]) & 0xFF;
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return -1;
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}
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public synchronized int read(byte[] b, int off, int len)
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{
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/* Don't need to check pos value, arraycopy will check it. */
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if (off < 0 || len < 0 || off + len > b.length)
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throw new ArrayIndexOutOfBoundsException();
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if (pos >= count)
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return -1;
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int numBytes = Math.min(count - pos, len);
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System.arraycopy(buf, pos, b, off, numBytes);
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pos += numBytes;
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return numBytes;
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}
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public synchronized void reset()
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{
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pos = mark;
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}
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public synchronized long skip(long n)
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{
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// Even though the var numBytes is a long, in reality it can never
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// be larger than an int since the result of subtracting 2 positive
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// ints will always fit in an int. Since we have to return a long
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// anyway, numBytes might as well just be a long.
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long numBytes = Math.min((long) (count - pos), n < 0 ? 0L : n);
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pos += numBytes;
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return numBytes;
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}
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}
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