CharSequenceReader.java

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/*
 * Javolution - Java(TM) Solution for Real-Time and Embedded Systems
 * Copyright (C) 2012 - Javolution (http://javolution.org/)
 * All rights reserved.
 * 
 * Permission to use, copy, modify, and distribute this software is
 * freely granted, provided that this notice is preserved.
 */
package javolution.io;
 
import java.io.IOException;
import java.io.Reader;
import javolution.lang.MathLib;
import javolution.text.CharArray;
import javolution.text.Text;
import javolution.text.TextBuilder;
 
public final class CharSequenceReader extends Reader {
 
    private CharSequence _input;
 
    private int _index;
 
    public CharSequenceReader() {}
 
    public CharSequenceReader setInput(CharSequence charSequence) {
        if (_input != null)
            throw new IllegalStateException("Reader not closed or reset");
        _input = charSequence;
        return this;
    }
 
    public boolean ready() throws IOException {
        if (_input == null)
            throw new IOException("Reader closed");
        return true;
    }
 
    public void close() {
        if (_input != null) {
            reset();
        }
    }
 
    public int read() throws IOException {
        if (_input == null)
            throw new IOException("Reader closed");
        return (_index < _input.length()) ? _input.charAt(_index++) : -1;
    }
 
    public int read(char cbuf[], int off, int len) throws IOException {
        if (_input == null)
            throw new IOException("Reader closed");
        final int inputLength = _input.length();
        if (_index >= inputLength)
            return -1;
        final int count = MathLib.min(inputLength - _index, len);
        final Object csq = _input;
        if (csq instanceof String) {
            String str = (String) csq;
            str.getChars(_index, _index + count, cbuf, off);
        } else if (csq instanceof Text) {
            Text txt = (Text) csq;
            txt.getChars(_index, _index + count, cbuf, off);
        } else if (csq instanceof TextBuilder) {
            TextBuilder tb = (TextBuilder) csq;
            tb.getChars(_index, _index + count, cbuf, off);
        } else if (csq instanceof CharArray) {
            CharArray ca = (CharArray) csq;
            System.arraycopy(ca.array(), _index + ca.offset(), cbuf, off, count);
        } else { // Generic CharSequence.
            for (int i = off, n = off + count, j = _index; i < n;) {
                cbuf[i++] = _input.charAt(j++);
            }
        }
        _index += count;
        return count;
    }
 
    public void read(Appendable dest) throws IOException {
        if (_input == null)
            throw new IOException("Reader closed");
        dest.append(_input);
    }
 
    @Override
    public void reset() {
        _index = 0;
        _input = null;
    }
 
}