package com.elharo.io;

import java.io.*;

public class UnsynchronizedBufferedWriter extends Writer {
  
  private final static int CAPACITY = 8192;
  
  private char[]  buffer = new char[CAPACITY];
  private int     position = 0;
  private Writer  out;
  private boolean closed = false;
  
  public UnsynchronizedBufferedWriter(Writer out) {
    this.out = out;
  }

  public void write(char[] text, int offset, int length) throws IOException {
    checkClosed();
    while (length > 0) {
      int n = Math.min(CAPACITY - position, length);
      System.arraycopy(text, offset, buffer, position, n);
      position += n;
      offset += n;
      length -= n;
      if (position >= CAPACITY) flushInternal();
    }
  }
  
  public void write(String s) throws IOException {
     write(s, 0, s.length());
  }
  
  public void write(String s, int offset, int length) throws IOException {
    checkClosed();
    while (length > 0) {
      int n = Math.min(CAPACITY - position, length);
      s.getChars(offset, offset + n, buffer, position);
      position += n;
      offset += n;
      length -= n;
      if (position >= CAPACITY) flushInternal();
    }   
  }   
  
  public void write(int c) throws IOException {
    checkClosed();
    if (position >= CAPACITY) flushInternal();
    buffer[position] = (char) c;
    position++;
  }
  
  public void flush() throws IOException {
    flushInternal();
    out.flush();
  }

  private void flushInternal() throws IOException {
    if (position != 0) {
      out.write(buffer, 0, position);
      position = 0;
    }
  }
  
  public void close() throws IOException {
    closed = true;
    this.flush();
    out.close();
  }
  
  private void checkClosed() throws IOException {
    if (closed) throw new IOException("Writer is closed"); 
  } 
}