| /* |
| * Copyright (c) 1996, 2021, 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.nio.CharBuffer; |
| import java.util.Objects; |
| |
| /** |
| * This class implements a character buffer that can be used as a |
| * character-input stream. |
| * |
| * @author Herb Jellinek |
| * @since 1.1 |
| */ |
| public class CharArrayReader extends Reader { |
| /** The character buffer. */ |
| protected char[] buf; |
| |
| /** The current buffer position. */ |
| protected int pos; |
| |
| /** The position of mark in buffer. */ |
| protected int markedPos = 0; |
| |
| /** |
| * The index of the end of this buffer. There is not valid |
| * data at or beyond this index. |
| */ |
| protected int count; |
| |
| /** |
| * Creates a CharArrayReader from the specified array of chars. |
| * @param buf Input buffer (not copied) |
| */ |
| public CharArrayReader(char[] buf) { |
| this.buf = buf; |
| this.pos = 0; |
| this.count = buf.length; |
| } |
| |
| /** |
| * Creates a CharArrayReader from the specified array of chars. |
| * |
| * <p> The resulting reader will start reading at the given |
| * {@code offset}. The total number of {@code char} values that can be |
| * read from this reader will be either {@code length} or |
| * {@code buf.length-offset}, whichever is smaller. |
| * |
| * @throws IllegalArgumentException |
| * If {@code offset} is negative or greater than |
| * {@code buf.length}, or if {@code length} is negative, or if |
| * the sum of these two values is negative. |
| * |
| * @param buf Input buffer (not copied) |
| * @param offset Offset of the first char to read |
| * @param length Number of chars to read |
| */ |
| public CharArrayReader(char[] buf, int offset, int length) { |
| if ((offset < 0) || (offset > buf.length) || (length < 0) || |
| ((offset + length) < 0)) { |
| throw new IllegalArgumentException(); |
| } |
| this.buf = buf; |
| this.pos = offset; |
| this.count = Math.min(offset + length, buf.length); |
| this.markedPos = offset; |
| } |
| |
| /** Checks to make sure that the stream has not been closed */ |
| private void ensureOpen() throws IOException { |
| if (buf == null) |
| throw new IOException("Stream closed"); |
| } |
| |
| /** |
| * Reads a single character. |
| * |
| * @throws IOException If an I/O error occurs |
| */ |
| public int read() throws IOException { |
| synchronized (lock) { |
| ensureOpen(); |
| if (pos >= count) |
| return -1; |
| else |
| return buf[pos++]; |
| } |
| } |
| |
| /** |
| * Reads characters into a portion of an array. |
| * |
| * <p> If {@code len} is zero, then no characters are read and {@code 0} is |
| * returned; otherwise, there is an attempt to read at least one character. |
| * If no character is available because the stream is at its end, the value |
| * {@code -1} is returned; otherwise, at least one character is read and |
| * stored into {@code cbuf}. |
| * |
| * @param cbuf {@inheritDoc} |
| * @param off {@inheritDoc} |
| * @param len {@inheritDoc} |
| * |
| * @return {@inheritDoc} |
| * |
| * @throws IndexOutOfBoundsException {@inheritDoc} |
| * @throws IOException {@inheritDoc} |
| */ |
| public int read(char[] cbuf, int off, int len) throws IOException { |
| synchronized (lock) { |
| ensureOpen(); |
| Objects.checkFromIndexSize(off, len, cbuf.length); |
| if (len == 0) { |
| return 0; |
| } |
| |
| if (pos >= count) { |
| return -1; |
| } |
| |
| int avail = count - pos; |
| if (len > avail) { |
| len = avail; |
| } |
| if (len <= 0) { |
| return 0; |
| } |
| System.arraycopy(buf, pos, cbuf, off, len); |
| pos += len; |
| return len; |
| } |
| } |
| |
| @Override |
| public int read(CharBuffer target) throws IOException { |
| synchronized (lock) { |
| ensureOpen(); |
| |
| if (pos >= count) { |
| return -1; |
| } |
| |
| int avail = count - pos; |
| int len = Math.min(avail, target.remaining()); |
| target.put(buf, pos, len); |
| pos += len; |
| return len; |
| } |
| } |
| |
| /** |
| * Skips characters. If the stream is already at its end before this method |
| * is invoked, then no characters are skipped and zero is returned. |
| * |
| * <p>The {@code n} parameter may be negative, even though the |
| * {@code skip} method of the {@link Reader} superclass throws |
| * an exception in this case. If {@code n} is negative, then |
| * this method does nothing and returns {@code 0}. |
| * |
| * @param n {@inheritDoc} |
| * |
| * @return {@inheritDoc} |
| * |
| * @throws IOException {@inheritDoc} |
| */ |
| public long skip(long n) throws IOException { |
| synchronized (lock) { |
| ensureOpen(); |
| |
| long avail = count - pos; |
| if (n > avail) { |
| n = avail; |
| } |
| if (n < 0) { |
| return 0; |
| } |
| pos += n; |
| return n; |
| } |
| } |
| |
| /** |
| * Tells whether this stream is ready to be read. Character-array readers |
| * are always ready to be read. |
| * |
| * @throws IOException If an I/O error occurs |
| */ |
| public boolean ready() throws IOException { |
| synchronized (lock) { |
| ensureOpen(); |
| return (count - pos) > 0; |
| } |
| } |
| |
| /** |
| * Tells whether this stream supports the mark() operation, which it does. |
| */ |
| public boolean markSupported() { |
| return true; |
| } |
| |
| /** |
| * Marks the present position in the stream. Subsequent calls to reset() |
| * will reposition the stream to this point. |
| * |
| * @param readAheadLimit Limit on the number of characters that may be |
| * read while still preserving the mark. Because |
| * the stream's input comes from a character array, |
| * there is no actual limit; hence this argument is |
| * ignored. |
| * |
| * @throws IOException If an I/O error occurs |
| */ |
| public void mark(int readAheadLimit) throws IOException { |
| synchronized (lock) { |
| ensureOpen(); |
| markedPos = pos; |
| } |
| } |
| |
| /** |
| * Resets the stream to the most recent mark, or to the beginning if it has |
| * never been marked. |
| * |
| * @throws IOException If an I/O error occurs |
| */ |
| public void reset() throws IOException { |
| synchronized (lock) { |
| ensureOpen(); |
| pos = markedPos; |
| } |
| } |
| |
| /** |
| * Closes the stream and releases any system resources associated with |
| * it. Once the stream has been closed, further read(), ready(), |
| * mark(), reset(), or skip() invocations will throw an IOException. |
| * Closing a previously closed stream has no effect. This method will block |
| * while there is another thread blocking on the reader. |
| */ |
| public void close() { |
| synchronized (lock) { |
| buf = null; |
| } |
| } |
| } |
