/*
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* Copyright (c) 2018-2028, DreamLu All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* Neither the name of the dreamlu.net developer nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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* Author: DreamLu 卢春梦 (596392912@qq.com)
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*/
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package org.springblade.core.tool.support;
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import org.springblade.core.tool.utils.StringPool;
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import java.io.IOException;
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import java.io.Writer;
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import java.util.Arrays;
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/**
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* FastStringWriter，更改于 jdk CharArrayWriter
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*
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* <p>
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* 1. 去掉了锁
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* 2. 初始容量由 32 改为 64
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* </p>
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*
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* @author L.cm
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*/
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public class FastStringWriter extends Writer {
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/**
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* The buffer where data is stored.
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*/
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private char[] buf;
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/**
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* The number of chars in the buffer.
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*/
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private int count;
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/**
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* Creates a new CharArrayWriter.
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*/
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public FastStringWriter() {
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this(64);
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}
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/**
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* Creates a new CharArrayWriter with the specified initial size.
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*
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* @param initialSize an int specifying the initial buffer size.
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* @throws IllegalArgumentException if initialSize is negative
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*/
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public FastStringWriter(int initialSize) {
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if (initialSize < 0) {
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throw new IllegalArgumentException("Negative initial size: " + initialSize);
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}
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buf = new char[initialSize];
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}
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/**
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* Writes a character to the buffer.
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*/
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@Override
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public void write(int c) {
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int newCount = count + 1;
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if (newCount > buf.length) {
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buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newCount));
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}
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buf[count] = (char) c;
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count = newCount;
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}
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/**
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* Writes characters to the buffer.
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*
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* @param c the data to be written
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* @param off the start offset in the data
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* @param len the number of chars that are written
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*/
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@Override
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public void write(char[] c, int off, int len) {
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if ((off < 0) || (off > c.length) || (len < 0) ||
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((off + len) > c.length) || ((off + len) < 0)) {
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throw new IndexOutOfBoundsException();
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} else if (len == 0) {
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return;
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}
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int newCount = count + len;
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if (newCount > buf.length) {
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buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newCount));
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}
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System.arraycopy(c, off, buf, count, len);
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count = newCount;
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}
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/**
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* Write a portion of a string to the buffer.
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*
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* @param str String to be written from
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* @param off Offset from which to start reading characters
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* @param len Number of characters to be written
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*/
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@Override
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public void write(String str, int off, int len) {
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int newCount = count + len;
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if (newCount > buf.length) {
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buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newCount));
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}
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str.getChars(off, off + len, buf, count);
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count = newCount;
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}
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/**
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* Writes the contents of the buffer to another character stream.
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*
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* @param out the output stream to write to
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* @throws IOException If an I/O error occurs.
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*/
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public void writeTo(Writer out) throws IOException {
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out.write(buf, 0, count);
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}
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/**
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* Appends the specified character sequence to this writer.
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*
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* <p> An invocation of this method of the form <tt>out.append(csq)</tt>
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* behaves in exactly the same way as the invocation
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*
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* <pre>
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* out.write(csq.toString()) </pre>
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*
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* <p> Depending on the specification of <tt>toString</tt> for the
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* character sequence <tt>csq</tt>, the entire sequence may not be
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* appended. For instance, invoking the <tt>toString</tt> method of a
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* character buffer will return a subsequence whose content depends upon
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* the buffer's position and limit.
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*
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* @param csq The character sequence to append. If <tt>csq</tt> is
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* <tt>null</tt>, then the four characters <tt>"null"</tt> are
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* appended to this writer.
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* @return This writer
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*/
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@Override
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public FastStringWriter append(CharSequence csq) {
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String s = (csq == null ? StringPool.NULL : csq.toString());
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write(s, 0, s.length());
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return this;
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}
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/**
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* Appends a subsequence of the specified character sequence to this writer.
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*
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* <p> An invocation of this method of the form <tt>out.append(csq, start,
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* end)</tt> when <tt>csq</tt> is not <tt>null</tt>, behaves in
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* exactly the same way as the invocation
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*
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* <pre>
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* out.write(csq.subSequence(start, end).toString()) </pre>
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*
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* @param csq The character sequence from which a subsequence will be
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* appended. If <tt>csq</tt> is <tt>null</tt>, then characters
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* will be appended as if <tt>csq</tt> contained the four
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* characters <tt>"null"</tt>.
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* @param start The index of the first character in the subsequence
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* @param end The index of the character following the last character in the
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* subsequence
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* @return This writer
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* @throws IndexOutOfBoundsException If <tt>start</tt> or <tt>end</tt> are negative, <tt>start</tt>
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* is greater than <tt>end</tt>, or <tt>end</tt> is greater than
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* <tt>csq.length()</tt>
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*/
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@Override
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public FastStringWriter append(CharSequence csq, int start, int end) {
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String s = (csq == null ? StringPool.NULL : csq).subSequence(start, end).toString();
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write(s, 0, s.length());
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return this;
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}
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/**
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* Appends the specified character to this writer.
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*
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* <p> An invocation of this method of the form <tt>out.append(c)</tt>
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* behaves in exactly the same way as the invocation
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*
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* <pre>
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* out.write(c) </pre>
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*
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* @param c The 16-bit character to append
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* @return This writer
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*/
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@Override
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public FastStringWriter append(char c) {
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write(c);
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return this;
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}
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/**
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* Resets the buffer so that you can use it again without
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* throwing away the already allocated buffer.
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*/
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public void reset() {
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count = 0;
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}
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/**
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* Returns a copy of the input data.
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*
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* @return an array of chars copied from the input data.
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*/
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public char[] toCharArray() {
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return Arrays.copyOf(buf, count);
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}
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/**
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* Returns the current size of the buffer.
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*
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* @return an int representing the current size of the buffer.
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*/
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public int size() {
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return count;
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}
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/**
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* Converts input data to a string.
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*
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* @return the string.
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*/
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@Override
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public String toString() {
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return new String(buf, 0, count);
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}
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/**
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* Flush the stream.
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*/
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@Override
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public void flush() {
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}
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/**
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* Close the stream. This method does not release the buffer, since its
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* contents might still be required. Note: Invoking this method in this class
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* will have no effect.
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*/
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@Override
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public void close() {
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}
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}
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