/*

  * Copyright 2012 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 java.util.HashMap;

 import java.util.Map;

 import eu.simuline.octave.exception.OctaveParseException;

 import eu.simuline.octave.io.OctaveIO;

 import eu.simuline.octave.io.spi.OctaveDataReader;

 import eu.simuline.octave.type.OctaveObject;

 import eu.simuline.octave.type.OctaveStruct;

 /**

  * The reader for the octave type "scalar struct" 

  * (which is an encoding similar to "struct" 

  * introduced in octave 3.6, optimized to the 1x1 struct) 

  * reading an {@link OctaveObject} from a {@link BufferedReader}.

  */

 public final class ScalarStructReader extends OctaveDataReader {

     private static final String NAME = "# name: ";

     private static final String LENGTH = "# length: ";

     private static final String N_DIMS2 = "# ndims: 2";

     private static final String V_DIMS2 = " 1 1";

     @Override

     public String octaveType() {

         return "scalar struct";

     }

     @Override

     public OctaveStruct read(final BufferedReader reader) {

         // **** this i cannot see in Writer 

         // # ndims: 2

         String line = OctaveIO.readerReadLine(reader);

         if (!N_DIMS2.equals(line)) {

             throw new OctaveParseException

                 ("JavaOctave does not support matrix structs, read=" + line);

         }

         // 1 1

         line = OctaveIO.readerReadLine(reader);

         if (!V_DIMS2.equals(line)) {

             throw new OctaveParseException

                 ("JavaOctave does not support matrix structs, read=" + line);

         }

         // # length: 4

         line = OctaveIO.readerReadLine(reader);

         if (line == null || !line.startsWith(LENGTH)) {

             throw new OctaveParseException

                 ("Expected <" + LENGTH + "> got <" + line + ">. ");

        }

         final int length = Integer.parseInt(line.substring(LENGTH.length()));

         // only used during conversion

         final Map<String, OctaveObject> data =

             new HashMap<String, OctaveObject>();

         for (int i = 0; i < length; i++) {

             // # name: elemmatrix

             // Work around differences in number of line feeds 

             // in octave 3.4 and 3.6

             // keep reading until line is non-empty

             do {

                 line = OctaveIO.readerReadLine(reader);

             } while ("".equals(line));

             if (!line.startsWith(NAME)) {

                 throw new OctaveParseException

                     ("Expected <" + NAME + "> got <" + line + ">. ");

             }

             final String subname = line.substring(NAME.length());

             // data...

             final OctaveObject value = OctaveIO.read(reader);

             data.put(subname, value);

         } // for

         return new OctaveStruct(data);

     }

 }