/*
 * Copyright (c) 1996, 2016, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package java.io;

import java.util.Arrays;

/**
 * This class implements a character buffer that can be used as an Writer.
 * The buffer automatically grows when data is written to the stream. The data
 * can be retrieved using toCharArray() and toString().
 * <P>
 * Note: Invoking close() on this class has no effect, and methods
 * of this class can be called after the stream has closed
 * without generating an IOException.
 *
 * @author Herb Jellinek
 * @since 1.1
 */
public
class CharArrayWriter extends Writer {
 /**
 * The buffer where data is stored.
 */
 protected char buf[];

 /**
 * The number of chars in the buffer.
 */
 protected int count;

 /**
 * Creates a new CharArrayWriter.
 */
 public CharArrayWriter() {
 this(32);
 }

 /**
 * Creates a new CharArrayWriter with the specified initial size.
 *
 * @param initialSize an int specifying the initial buffer size.
 * @exception IllegalArgumentException if initialSize is negative
 */
 public CharArrayWriter(int initialSize) {
 if (initialSize < 0) {
 throw new IllegalArgumentException("Negative initial size: "
 + initialSize);
 }
 buf = new char[initialSize];
 }

 /**
 * Writes a character to the buffer.
 */
 public void write(int c) {
 synchronized (lock) {
 int newcount = count + 1;
 if (newcount > buf.length) {
 buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));
 }
 buf[count] = (char)c;
 count = newcount;
 }
 }

 /**
 * Writes characters to the buffer.
 * @param c the data to be written
 * @param off the start offset in the data
 * @param len the number of chars that are written
 *
 * @throws IndexOutOfBoundsException
 * If {@code off} is negative, or {@code len} is negative,
 * or {@code off + len} is negative or greater than the length
 * of the given array
 */
 public void write(char c[], int off, int len) {
 if ((off < 0) || (off > c.length) || (len < 0) ||
 ((off + len) > c.length) || ((off + len) < 0)) {
 throw new IndexOutOfBoundsException();
 } else if (len == 0) {
 return;
 }
 synchronized (lock) {
 int newcount = count + len;
 if (newcount > buf.length) {
 buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));
 }
 System.arraycopy(c, off, buf, count, len);
 count = newcount;
 }
 }

 /**
 * Write a portion of a string to the buffer.
 * @param str String to be written from
 * @param off Offset from which to start reading characters
 * @param len Number of characters to be written
 *
 * @throws IndexOutOfBoundsException
 * If {@code off} is negative, or {@code len} is negative,
 * or {@code off + len} is negative or greater than the length
 * of the given string
 */
 public void write(String str, int off, int len) {
 synchronized (lock) {
 int newcount = count + len;
 if (newcount > buf.length) {
 buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));
 }
 str.getChars(off, off + len, buf, count);
 count = newcount;
 }
 }

 /**
 * Writes the contents of the buffer to another character stream.
 *
 * @param out the output stream to write to
 * @throws IOException If an I/O error occurs.
 */
 public void writeTo(Writer out) throws IOException {
 synchronized (lock) {
 out.write(buf, 0, count);
 }
 }

 /**
 * Appends the specified character sequence to this writer.
 *
 * <p> An invocation of this method of the form {@code out.append(csq)}
 * behaves in exactly the same way as the invocation
 *
 * <pre>
 * out.write(csq.toString()) </pre>
 *
 * <p> Depending on the specification of {@code toString} for the
 * character sequence {@code csq}, the entire sequence may not be
 * appended. For instance, invoking the {@code toString} method of a
 * character buffer will return a subsequence whose content depends upon
 * the buffer's position and limit.
 *
 * @param csq
 * The character sequence to append. If {@code csq} is
 * {@code null}, then the four characters {@code "null"} are
 * appended to this writer.
 *
 * @return This writer
 *
 * @since 1.5
 */
 public CharArrayWriter append(CharSequence csq) {
 String s = String.valueOf(csq);
 write(s, 0, s.length());
 return this;
 }

 /**
 * Appends a subsequence of the specified character sequence to this writer.
 *
 * <p> An invocation of this method of the form
 * {@code out.append(csq, start, end)} when
 * {@code csq} is not {@code null}, behaves in
 * exactly the same way as the invocation
 *
 * <pre>
 * out.write(csq.subSequence(start, end).toString()) </pre>
 *
 * @param csq
 * The character sequence from which a subsequence will be
 * appended. If {@code csq} is {@code null}, then characters
 * will be appended as if {@code csq} contained the four
 * characters {@code "null"}.
 *
 * @param start
 * The index of the first character in the subsequence
 *
 * @param end
 * The index of the character following the last character in the
 * subsequence
 *
 * @return This writer
 *
 * @throws IndexOutOfBoundsException
 * If {@code start} or {@code end} are negative, {@code start}
 * is greater than {@code end}, or {@code end} is greater than
 * {@code csq.length()}
 *
 * @since 1.5
 */
 public CharArrayWriter append(CharSequence csq, int start, int end) {
 if (csq == null) csq = "null";
 return append(csq.subSequence(start, end));
 }

 /**
 * Appends the specified character to this writer.
 *
 * <p> An invocation of this method of the form {@code out.append(c)}
 * behaves in exactly the same way as the invocation
 *
 * <pre>
 * out.write(c) </pre>
 *
 * @param c
 * The 16-bit character to append
 *
 * @return This writer
 *
 * @since 1.5
 */
 public CharArrayWriter append(char c) {
 write(c);
 return this;
 }

 /**
 * Resets the buffer so that you can use it again without
 * throwing away the already allocated buffer.
 */
 public void reset() {
 count = 0;
 }

 /**
 * Returns a copy of the input data.
 *
 * @return an array of chars copied from the input data.
 */
 public char[] toCharArray() {
 synchronized (lock) {
 return Arrays.copyOf(buf, count);
 }
 }

 /**
 * Returns the current size of the buffer.
 *
 * @return an int representing the current size of the buffer.
 */
 public int size() {
 return count;
 }

 /**
 * Converts input data to a string.
 * @return the string.
 */
 public String toString() {
 synchronized (lock) {
 return new String(buf, 0, count);
 }
 }

 /**
 * Flush the stream.
 */
 public void flush() { }

 /**
 * Close the stream. This method does not release the buffer, since its
 * contents might still be required. Note: Invoking this method in this class
 * will have no effect.
 */
 public void close() { }

}