jaroslav@163: /*
jaroslav@163:  * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
jaroslav@163:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
jaroslav@163:  *
jaroslav@163:  * This code is free software; you can redistribute it and/or modify it
jaroslav@163:  * under the terms of the GNU General Public License version 2 only, as
jaroslav@163:  * published by the Free Software Foundation.  Oracle designates this
jaroslav@163:  * particular file as subject to the "Classpath" exception as provided
jaroslav@163:  * by Oracle in the LICENSE file that accompanied this code.
jaroslav@163:  *
jaroslav@163:  * This code is distributed in the hope that it will be useful, but WITHOUT
jaroslav@163:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
jaroslav@163:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
jaroslav@163:  * version 2 for more details (a copy is included in the LICENSE file that
jaroslav@163:  * accompanied this code).
jaroslav@163:  *
jaroslav@163:  * You should have received a copy of the GNU General Public License version
jaroslav@163:  * 2 along with this work; if not, write to the Free Software Foundation,
jaroslav@163:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
jaroslav@163:  *
jaroslav@163:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
jaroslav@163:  * or visit www.oracle.com if you need additional information or have any
jaroslav@163:  * questions.
jaroslav@163:  */
jaroslav@163: 
jaroslav@163: package java.io;
jaroslav@163: 
jaroslav@560: import org.apidesign.bck2brwsr.emul.lang.System;
jaroslav@560: 
jaroslav@163: /**
jaroslav@163:  * A <code>ByteArrayInputStream</code> contains
jaroslav@163:  * an internal buffer that contains bytes that
jaroslav@163:  * may be read from the stream. An internal
jaroslav@163:  * counter keeps track of the next byte to
jaroslav@163:  * be supplied by the <code>read</code> method.
jaroslav@163:  * <p>
jaroslav@163:  * Closing a <tt>ByteArrayInputStream</tt> has no effect. The methods in
jaroslav@163:  * this class can be called after the stream has been closed without
jaroslav@163:  * generating an <tt>IOException</tt>.
jaroslav@163:  *
jaroslav@163:  * @author  Arthur van Hoff
jaroslav@163:  * @see     java.io.StringBufferInputStream
jaroslav@163:  * @since   JDK1.0
jaroslav@163:  */
jaroslav@163: public
jaroslav@163: class ByteArrayInputStream extends InputStream {
jaroslav@163: 
jaroslav@163:     /**
jaroslav@163:      * An array of bytes that was provided
jaroslav@163:      * by the creator of the stream. Elements <code>buf[0]</code>
jaroslav@163:      * through <code>buf[count-1]</code> are the
jaroslav@163:      * only bytes that can ever be read from the
jaroslav@163:      * stream;  element <code>buf[pos]</code> is
jaroslav@163:      * the next byte to be read.
jaroslav@163:      */
jaroslav@163:     protected byte buf[];
jaroslav@163: 
jaroslav@163:     /**
jaroslav@163:      * The index of the next character to read from the input stream buffer.
jaroslav@163:      * This value should always be nonnegative
jaroslav@163:      * and not larger than the value of <code>count</code>.
jaroslav@163:      * The next byte to be read from the input stream buffer
jaroslav@163:      * will be <code>buf[pos]</code>.
jaroslav@163:      */
jaroslav@163:     protected int pos;
jaroslav@163: 
jaroslav@163:     /**
jaroslav@163:      * The currently marked position in the stream.
jaroslav@163:      * ByteArrayInputStream objects are marked at position zero by
jaroslav@163:      * default when constructed.  They may be marked at another
jaroslav@163:      * position within the buffer by the <code>mark()</code> method.
jaroslav@163:      * The current buffer position is set to this point by the
jaroslav@163:      * <code>reset()</code> method.
jaroslav@163:      * <p>
jaroslav@163:      * If no mark has been set, then the value of mark is the offset
jaroslav@163:      * passed to the constructor (or 0 if the offset was not supplied).
jaroslav@163:      *
jaroslav@163:      * @since   JDK1.1
jaroslav@163:      */
jaroslav@163:     protected int mark = 0;
jaroslav@163: 
jaroslav@163:     /**
jaroslav@163:      * The index one greater than the last valid character in the input
jaroslav@163:      * stream buffer.
jaroslav@163:      * This value should always be nonnegative
jaroslav@163:      * and not larger than the length of <code>buf</code>.
jaroslav@163:      * It  is one greater than the position of
jaroslav@163:      * the last byte within <code>buf</code> that
jaroslav@163:      * can ever be read  from the input stream buffer.
jaroslav@163:      */
jaroslav@163:     protected int count;
jaroslav@163: 
jaroslav@163:     /**
jaroslav@163:      * Creates a <code>ByteArrayInputStream</code>
jaroslav@163:      * so that it  uses <code>buf</code> as its
jaroslav@163:      * buffer array.
jaroslav@163:      * The buffer array is not copied.
jaroslav@163:      * The initial value of <code>pos</code>
jaroslav@163:      * is <code>0</code> and the initial value
jaroslav@163:      * of  <code>count</code> is the length of
jaroslav@163:      * <code>buf</code>.
jaroslav@163:      *
jaroslav@163:      * @param   buf   the input buffer.
jaroslav@163:      */
jaroslav@163:     public ByteArrayInputStream(byte buf[]) {
jaroslav@163:         this.buf = buf;
jaroslav@163:         this.pos = 0;
jaroslav@163:         this.count = buf.length;
jaroslav@163:     }
jaroslav@163: 
jaroslav@163:     /**
jaroslav@163:      * Creates <code>ByteArrayInputStream</code>
jaroslav@163:      * that uses <code>buf</code> as its
jaroslav@163:      * buffer array. The initial value of <code>pos</code>
jaroslav@163:      * is <code>offset</code> and the initial value
jaroslav@163:      * of <code>count</code> is the minimum of <code>offset+length</code>
jaroslav@163:      * and <code>buf.length</code>.
jaroslav@163:      * The buffer array is not copied. The buffer's mark is
jaroslav@163:      * set to the specified offset.
jaroslav@163:      *
jaroslav@163:      * @param   buf      the input buffer.
jaroslav@163:      * @param   offset   the offset in the buffer of the first byte to read.
jaroslav@163:      * @param   length   the maximum number of bytes to read from the buffer.
jaroslav@163:      */
jaroslav@163:     public ByteArrayInputStream(byte buf[], int offset, int length) {
jaroslav@163:         this.buf = buf;
jaroslav@163:         this.pos = offset;
jaroslav@163:         this.count = Math.min(offset + length, buf.length);
jaroslav@163:         this.mark = offset;
jaroslav@163:     }
jaroslav@163: 
jaroslav@163:     /**
jaroslav@163:      * Reads the next byte of data from this input stream. The value
jaroslav@163:      * byte is returned as an <code>int</code> in the range
jaroslav@163:      * <code>0</code> to <code>255</code>. If no byte is available
jaroslav@163:      * because the end of the stream has been reached, the value
jaroslav@163:      * <code>-1</code> is returned.
jaroslav@163:      * <p>
jaroslav@163:      * This <code>read</code> method
jaroslav@163:      * cannot block.
jaroslav@163:      *
jaroslav@163:      * @return  the next byte of data, or <code>-1</code> if the end of the
jaroslav@163:      *          stream has been reached.
jaroslav@163:      */
jaroslav@163:     public synchronized int read() {
jaroslav@163:         return (pos < count) ? (buf[pos++] & 0xff) : -1;
jaroslav@163:     }
jaroslav@163: 
jaroslav@163:     /**
jaroslav@163:      * Reads up to <code>len</code> bytes of data into an array of bytes
jaroslav@163:      * from this input stream.
jaroslav@163:      * If <code>pos</code> equals <code>count</code>,
jaroslav@163:      * then <code>-1</code> is returned to indicate
jaroslav@163:      * end of file. Otherwise, the  number <code>k</code>
jaroslav@163:      * of bytes read is equal to the smaller of
jaroslav@163:      * <code>len</code> and <code>count-pos</code>.
jaroslav@163:      * If <code>k</code> is positive, then bytes
jaroslav@163:      * <code>buf[pos]</code> through <code>buf[pos+k-1]</code>
jaroslav@163:      * are copied into <code>b[off]</code>  through
jaroslav@163:      * <code>b[off+k-1]</code> in the manner performed
jaroslav@163:      * by <code>System.arraycopy</code>. The
jaroslav@163:      * value <code>k</code> is added into <code>pos</code>
jaroslav@163:      * and <code>k</code> is returned.
jaroslav@163:      * <p>
jaroslav@163:      * This <code>read</code> method cannot block.
jaroslav@163:      *
jaroslav@163:      * @param   b     the buffer into which the data is read.
jaroslav@163:      * @param   off   the start offset in the destination array <code>b</code>
jaroslav@163:      * @param   len   the maximum number of bytes read.
jaroslav@163:      * @return  the total number of bytes read into the buffer, or
jaroslav@163:      *          <code>-1</code> if there is no more data because the end of
jaroslav@163:      *          the stream has been reached.
jaroslav@163:      * @exception  NullPointerException If <code>b</code> is <code>null</code>.
jaroslav@163:      * @exception  IndexOutOfBoundsException If <code>off</code> is negative,
jaroslav@163:      * <code>len</code> is negative, or <code>len</code> is greater than
jaroslav@163:      * <code>b.length - off</code>
jaroslav@163:      */
jaroslav@163:     public synchronized int read(byte b[], int off, int len) {
jaroslav@163:         if (b == null) {
jaroslav@163:             throw new NullPointerException();
jaroslav@163:         } else if (off < 0 || len < 0 || len > b.length - off) {
jaroslav@163:             throw new IndexOutOfBoundsException();
jaroslav@163:         }
jaroslav@163: 
jaroslav@163:         if (pos >= count) {
jaroslav@163:             return -1;
jaroslav@163:         }
jaroslav@163: 
jaroslav@163:         int avail = count - pos;
jaroslav@163:         if (len > avail) {
jaroslav@163:             len = avail;
jaroslav@163:         }
jaroslav@163:         if (len <= 0) {
jaroslav@163:             return 0;
jaroslav@163:         }
jaroslav@560:         System.arraycopy(buf, pos, b, off, len);
jaroslav@163:         pos += len;
jaroslav@163:         return len;
jaroslav@163:     }
jaroslav@163: 
jaroslav@163:     /**
jaroslav@163:      * Skips <code>n</code> bytes of input from this input stream. Fewer
jaroslav@163:      * bytes might be skipped if the end of the input stream is reached.
jaroslav@163:      * The actual number <code>k</code>
jaroslav@163:      * of bytes to be skipped is equal to the smaller
jaroslav@163:      * of <code>n</code> and  <code>count-pos</code>.
jaroslav@163:      * The value <code>k</code> is added into <code>pos</code>
jaroslav@163:      * and <code>k</code> is returned.
jaroslav@163:      *
jaroslav@163:      * @param   n   the number of bytes to be skipped.
jaroslav@163:      * @return  the actual number of bytes skipped.
jaroslav@163:      */
jaroslav@163:     public synchronized long skip(long n) {
jaroslav@163:         long k = count - pos;
jaroslav@163:         if (n < k) {
jaroslav@163:             k = n < 0 ? 0 : n;
jaroslav@163:         }
jaroslav@163: 
jaroslav@163:         pos += k;
jaroslav@163:         return k;
jaroslav@163:     }
jaroslav@163: 
jaroslav@163:     /**
jaroslav@163:      * Returns the number of remaining bytes that can be read (or skipped over)
jaroslav@163:      * from this input stream.
jaroslav@163:      * <p>
jaroslav@163:      * The value returned is <code>count&nbsp;- pos</code>,
jaroslav@163:      * which is the number of bytes remaining to be read from the input buffer.
jaroslav@163:      *
jaroslav@163:      * @return  the number of remaining bytes that can be read (or skipped
jaroslav@163:      *          over) from this input stream without blocking.
jaroslav@163:      */
jaroslav@163:     public synchronized int available() {
jaroslav@163:         return count - pos;
jaroslav@163:     }
jaroslav@163: 
jaroslav@163:     /**
jaroslav@163:      * Tests if this <code>InputStream</code> supports mark/reset. The
jaroslav@163:      * <code>markSupported</code> method of <code>ByteArrayInputStream</code>
jaroslav@163:      * always returns <code>true</code>.
jaroslav@163:      *
jaroslav@163:      * @since   JDK1.1
jaroslav@163:      */
jaroslav@163:     public boolean markSupported() {
jaroslav@163:         return true;
jaroslav@163:     }
jaroslav@163: 
jaroslav@163:     /**
jaroslav@163:      * Set the current marked position in the stream.
jaroslav@163:      * ByteArrayInputStream objects are marked at position zero by
jaroslav@163:      * default when constructed.  They may be marked at another
jaroslav@163:      * position within the buffer by this method.
jaroslav@163:      * <p>
jaroslav@163:      * If no mark has been set, then the value of the mark is the
jaroslav@163:      * offset passed to the constructor (or 0 if the offset was not
jaroslav@163:      * supplied).
jaroslav@163:      *
jaroslav@163:      * <p> Note: The <code>readAheadLimit</code> for this class
jaroslav@163:      *  has no meaning.
jaroslav@163:      *
jaroslav@163:      * @since   JDK1.1
jaroslav@163:      */
jaroslav@163:     public void mark(int readAheadLimit) {
jaroslav@163:         mark = pos;
jaroslav@163:     }
jaroslav@163: 
jaroslav@163:     /**
jaroslav@163:      * Resets the buffer to the marked position.  The marked position
jaroslav@163:      * is 0 unless another position was marked or an offset was specified
jaroslav@163:      * in the constructor.
jaroslav@163:      */
jaroslav@163:     public synchronized void reset() {
jaroslav@163:         pos = mark;
jaroslav@163:     }
jaroslav@163: 
jaroslav@163:     /**
jaroslav@163:      * Closing a <tt>ByteArrayInputStream</tt> has no effect. The methods in
jaroslav@163:      * this class can be called after the stream has been closed without
jaroslav@163:      * generating an <tt>IOException</tt>.
jaroslav@163:      * <p>
jaroslav@163:      */
jaroslav@163:     public void close() throws IOException {
jaroslav@163:     }
jaroslav@163: 
jaroslav@163: }