/*
 * Copyright (c) 1998-2011 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Resin Open Source 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, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *
 *   Free Software Foundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Sam
 */

package com.caucho.quercus.lib.file;

import com.caucho.quercus.env.Env;
import com.caucho.quercus.env.StringValue;

import java.io.IOException;

/**
 * A helper class that handles line endings when reading from a BinaryInput.
 */
public class LineReader
{
  private Boolean _isMacLineEnding;

  public LineReader(Env env)
  {
    this(FileModule.INI_AUTO_DETECT_LINE_ENDINGS.getAsBoolean(env));
  }

  private LineReader(boolean isAutoDetectLineEndings)
  {
    if (!isAutoDetectLineEndings)
      _isMacLineEnding = Boolean.FALSE;
  }

  /**
   * Reads a line from the BinaryInput, returning null on EOF.
   */
  public StringValue readLine(Env env, BinaryInput input, long length)
    throws IOException
  {
    StringValue sb = env.createBinaryBuilder();

    int ch;

    for (; length > 0 && (ch = input.read()) >= 0; length--) {
      // php/161[pq] newlines
      if (ch == '\n') {
        sb.appendByte((byte) ch);

        if (_isMacLineEnding == null)
          _isMacLineEnding = false;

        if (!_isMacLineEnding)
          break;
      }
      else if (ch == '\r') {
        sb.appendByte((byte) '\r');

        int ch2 = input.read();

        if (ch2 == '\n') {
          if (_isMacLineEnding == null)
            _isMacLineEnding = false;

          if (_isMacLineEnding) {
            input.unread();
            break;
          }
          else {
            sb.appendByte((byte) '\n');
            break;
          }
        }
        else {
          input.unread();

          if (_isMacLineEnding == null)
            _isMacLineEnding = true;

          if (_isMacLineEnding)
            return sb;
        }

      }
      else
        sb.appendByte((byte) ch);
    }

    if (sb.length() == 0)
      return null;
    else
      return sb;
    
  }
}