| /* | |
| * Copyright (c) 1996, 2022, 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 no 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 += (int) 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; | |
| } | |
| } | |
| } |