/*

  * 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());

     }

 }