| /* |
| * Copyright (c) 1994, 2018, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package java.io; |
| |
| import java.util.Arrays; |
| import java.util.Objects; |
| |
| /** |
| * A {@code ByteArrayInputStream} contains |
| * an internal buffer that contains bytes that |
| * may be read from the stream. An internal |
| * counter keeps track of the next byte to |
| * be supplied by the {@code read} method. |
| * <p> |
| * Closing a {@code ByteArrayInputStream} has no effect. The methods in |
| * this class can be called after the stream has been closed without |
| * generating an {@code IOException}. |
| * |
| * @author Arthur van Hoff |
| * @see java.io.StringBufferInputStream |
| * @since 1.0 |
| */ |
| public class ByteArrayInputStream extends InputStream { |
| |
| /** |
| * An array of bytes that was provided |
| * by the creator of the stream. Elements {@code buf[0]} |
| * through {@code buf[count-1]} are the |
| * only bytes that can ever be read from the |
| * stream; element {@code buf[pos]} is |
| * the next byte to be read. |
| */ |
| protected byte buf[]; |
| |
| /** |
| * The index of the next character to read from the input stream buffer. |
| * This value should always be nonnegative |
| * and not larger than the value of {@code count}. |
| * The next byte to be read from the input stream buffer |
| * will be {@code buf[pos]}. |
| */ |
| protected int pos; |
| |
| /** |
| * The currently marked position in the stream. |
| * ByteArrayInputStream objects are marked at position zero by |
| * default when constructed. They may be marked at another |
| * position within the buffer by the {@code mark()} method. |
| * The current buffer position is set to this point by the |
| * {@code reset()} method. |
| * <p> |
| * If no mark has been set, then the value of mark is the offset |
| * passed to the constructor (or 0 if the offset was not supplied). |
| * |
| * @since 1.1 |
| */ |
| protected int mark = 0; |
| |
| /** |
| * The index one greater than the last valid character in the input |
| * stream buffer. |
| * This value should always be nonnegative |
| * and not larger than the length of {@code buf}. |
| * It is one greater than the position of |
| * the last byte within {@code buf} that |
| * can ever be read from the input stream buffer. |
| */ |
| protected int count; |
| |
| /** |
| * Creates a {@code ByteArrayInputStream} |
| * so that it uses {@code buf} as its |
| * buffer array. |
| * The buffer array is not copied. |
| * The initial value of {@code pos} |
| * is {@code 0} and the initial value |
| * of {@code count} is the length of |
| * {@code buf}. |
| * |
| * @param buf the input buffer. |
| */ |
| public ByteArrayInputStream(byte buf[]) { |
| this.buf = buf; |
| this.pos = 0; |
| this.count = buf.length; |
| } |
| |
| /** |
| * Creates {@code ByteArrayInputStream} |
| * that uses {@code buf} as its |
| * buffer array. The initial value of {@code pos} |
| * is {@code offset} and the initial value |
| * of {@code count} is the minimum of {@code offset+length} |
| * and {@code buf.length}. |
| * The buffer array is not copied. The buffer's mark is |
| * set to the specified offset. |
| * |
| * @param buf the input buffer. |
| * @param offset the offset in the buffer of the first byte to read. |
| * @param length the maximum number of bytes to read from the buffer. |
| */ |
| public ByteArrayInputStream(byte buf[], int offset, int length) { |
| this.buf = buf; |
| this.pos = offset; |
| this.count = Math.min(offset + length, buf.length); |
| this.mark = offset; |
| } |
| |
| /** |
| * Reads the next byte of data from this input stream. The value |
| * byte is returned as an {@code int} in the range |
| * {@code 0} to {@code 255}. If no byte is available |
| * because the end of the stream has been reached, the value |
| * {@code -1} is returned. |
| * <p> |
| * This {@code read} method |
| * cannot block. |
| * |
| * @return the next byte of data, or {@code -1} if the end of the |
| * stream has been reached. |
| */ |
| public synchronized int read() { |
| return (pos < count) ? (buf[pos++] & 0xff) : -1; |
| } |
| |
| /** |
| * Reads up to {@code len} bytes of data into an array of bytes from this |
| * input stream. If {@code pos} equals {@code count}, then {@code -1} is |
| * returned to indicate end of file. Otherwise, the number {@code k} of |
| * bytes read is equal to the smaller of {@code len} and {@code count-pos}. |
| * If {@code k} is positive, then bytes {@code buf[pos]} through |
| * {@code buf[pos+k-1]} are copied into {@code b[off]} through |
| * {@code b[off+k-1]} in the manner performed by {@code System.arraycopy}. |
| * The value {@code k} is added into {@code pos} and {@code k} is returned. |
| * <p> |
| * This {@code read} method cannot block. |
| * |
| * @param b the buffer into which the data is read. |
| * @param off the start offset in the destination array {@code b} |
| * @param len the maximum number of bytes read. |
| * @return the total number of bytes read into the buffer, or |
| * {@code -1} if there is no more data because the end of |
| * the stream has been reached. |
| * @throws NullPointerException If {@code b} is {@code null}. |
| * @throws IndexOutOfBoundsException If {@code off} is negative, |
| * {@code len} is negative, or {@code len} is greater than |
| * {@code b.length - off} |
| */ |
| public synchronized int read(byte b[], int off, int len) { |
| Objects.checkFromIndexSize(off, len, b.length); |
| |
| if (pos >= count) { |
| return -1; |
| } |
| |
| int avail = count - pos; |
| if (len > avail) { |
| len = avail; |
| } |
| if (len <= 0) { |
| return 0; |
| } |
| System.arraycopy(buf, pos, b, off, len); |
| pos += len; |
| return len; |
| } |
| |
| public synchronized byte[] readAllBytes() { |
| byte[] result = Arrays.copyOfRange(buf, pos, count); |
| pos = count; |
| return result; |
| } |
| |
| public int readNBytes(byte[] b, int off, int len) { |
| int n = read(b, off, len); |
| return n == -1 ? 0 : n; |
| } |
| |
| public synchronized long transferTo(OutputStream out) throws IOException { |
| int len = count - pos; |
| out.write(buf, pos, len); |
| pos = count; |
| return len; |
| } |
| |
| /** |
| * Skips {@code n} bytes of input from this input stream. Fewer |
| * bytes might be skipped if the end of the input stream is reached. |
| * The actual number {@code k} |
| * of bytes to be skipped is equal to the smaller |
| * of {@code n} and {@code count-pos}. |
| * The value {@code k} is added into {@code pos} |
| * and {@code k} is returned. |
| * |
| * @param n the number of bytes to be skipped. |
| * @return the actual number of bytes skipped. |
| */ |
| public synchronized long skip(long n) { |
| long k = count - pos; |
| if (n < k) { |
| k = n < 0 ? 0 : n; |
| } |
| |
| pos += k; |
| return k; |
| } |
| |
| /** |
| * Returns the number of remaining bytes that can be read (or skipped over) |
| * from this input stream. |
| * <p> |
| * The value returned is {@code count - pos}, |
| * which is the number of bytes remaining to be read from the input buffer. |
| * |
| * @return the number of remaining bytes that can be read (or skipped |
| * over) from this input stream without blocking. |
| */ |
| public synchronized int available() { |
| return count - pos; |
| } |
| |
| /** |
| * Tests if this {@code InputStream} supports mark/reset. The |
| * {@code markSupported} method of {@code ByteArrayInputStream} |
| * always returns {@code true}. |
| * |
| * @since 1.1 |
| */ |
| public boolean markSupported() { |
| return true; |
| } |
| |
| /** |
| * Set the current marked position in the stream. |
| * ByteArrayInputStream objects are marked at position zero by |
| * default when constructed. They may be marked at another |
| * position within the buffer by this method. |
| * <p> |
| * If no mark has been set, then the value of the mark is the |
| * offset passed to the constructor (or 0 if the offset was not |
| * supplied). |
| * |
| * <p> Note: The {@code readAheadLimit} for this class |
| * has no meaning. |
| * |
| * @since 1.1 |
| */ |
| public void mark(int readAheadLimit) { |
| mark = pos; |
| } |
| |
| /** |
| * Resets the buffer to the marked position. The marked position |
| * is 0 unless another position was marked or an offset was specified |
| * in the constructor. |
| */ |
| public synchronized void reset() { |
| pos = mark; |
| } |
| |
| /** |
| * Closing a {@code ByteArrayInputStream} has no effect. The methods in |
| * this class can be called after the stream has been closed without |
| * generating an {@code IOException}. |
| */ |
| public void close() throws IOException { |
| } |
| |
| } |