/*
    * Copyright 2008 Ange Optimization ApS
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package eu.simuline.octave.io.impl;
  
  import java.io.BufferedReader;
  
  import eu.simuline.octave.exception.OctaveParseException;
  import eu.simuline.octave.io.OctaveIO;
  import eu.simuline.octave.io.spi.OctaveDataReader;
  import eu.simuline.octave.type.OctaveString;
  
  /**
   * The reader of string/sq_string. 
   *
   * @see OctaveStringReader
   * @see OctaveSqStringReader
   */
  public abstract class AbstractOctaveStringReader extends OctaveDataReader {
  
  
      private static final String H_ELEMENTS1 = "# elements: 1";
      private static final String H_ELEMENTS0 = "# elements: 0";
  
      private static final String LENGTH = "# length: ";
  
      /**
       * Overriding this method may add just handling of <code>\\</code> 
       * or delegate to this method. 
       */
      //@Override
      protected final OctaveString readImpl(final BufferedReader reader) {
          final String elements = OctaveIO.readerReadLine(reader);
          final StringBuilder builder = new StringBuilder();
  	// NOTE: in java > 1.7 strings are allowed in switch 
  	if (H_ELEMENTS1.equals(elements)) {
              final String lengthString = OctaveIO.readerReadLine(reader);
              if (!lengthString.startsWith(LENGTH)) {
                  throw new OctaveParseException
  		    ("Parse error in String, line='" + lengthString + "'");
              }
              final int length = Integer
  		.parseInt(lengthString.substring(LENGTH.length()));
  
              boolean first = true;
              while (builder.length() < length) {
                  if (!first) {
                      builder.append('\n');
                  }
                  builder.append(OctaveIO.readerReadLine(reader));
                  first = false;
              }
  
              if (builder.length() != length) {
                  throw new OctaveParseException
  		    ("Unexpected length of string read. expected=" + 
  		     length + ", actual=" + builder.length());
              }
          } else if (!H_ELEMENTS0.equals(elements)) {
              throw new OctaveParseException
  		("Expected elements to be 0 or 1, '" + elements + "'");
          }
          return new OctaveString(builder.toString());
      }
  }