/*

  * Copyright 2008, 2009, 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.OctaveCell;

 import eu.simuline.octave.type.OctaveObject;

 import eu.simuline.octave.type.OctaveStruct;

 import static eu.simuline.octave.io.impl.StructWriter.LENGTH;

 import static eu.simuline.octave.io.impl.StructWriter.NAME;

 import static eu.simuline.octave.io.impl.StructWriter.TYPE_CELL;

 /**

  * The reader for the octave type "struct" 

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

  * Reads the format written by {@link StructWriter}

  */

 public final class StructReader extends OctaveDataReader {

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

     private static final String V_DIMS2 = " 1 1";

     private static final CellReader CELL_READER = new CellReader();

     @Override

     public String octaveType() {

         return "struct";

     }

     @Override

     @SuppressWarnings("PMD.NPathComplexity")

     public OctaveStruct read(final BufferedReader reader) {

         String line = OctaveIO.readerReadLine(reader);

         // In octave 3.6 dimension of the scalar is also written now 

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

         if (line != null && line.startsWith("# ndims:")) {

             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 + "'");

             }

             line = OctaveIO.readerReadLine(reader);

         }

         // # length: 4

 //        String 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());

             line = OctaveIO.readerReadLine(reader);

             if (!line.equals(TYPE_CELL)) {

                 throw new OctaveParseException

                     ("Expected '" + TYPE_CELL + "' got '" + line + "'");

             }

             final OctaveCell cell = CELL_READER.read(reader);

             if (cell.getSize(1) != 1 || cell.getSize(2) != 1) {

                 throw new OctaveParseException

                     ("JavaOctave does not support matrix structs, size="

                      + cell.getSize(1) + " " + cell.getSize(2) + "...");

             }

             // data...

             final OctaveObject value = cell.get(1, 1);

             data.put(subname, value);

         } // for 

         return new OctaveStruct(data);

     }

 }