/*

  * Copyright 2010 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.OctaveSparseBoolean;

 import eu.simuline.octave.util.StringUtil;

 /**

  * The reader for the octave type "sparse bool matrix" 

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

  *

  * <pre>

  * # name: x

  * # type: sparse bool matrix

  * # nnz: 1

  * # rows: 1

  * # columns: 1

  * 1 1 1

  * </pre>

  */

 public final class SparseBooleanReader extends OctaveDataReader {

     @Override

     public String octaveType() {

         return "sparse bool matrix";

     }

     /**

      * @throws OctaveParseException

      */

     @Override

     @SuppressWarnings("checkstyle:magicnumber")

     // 3 is clear from SparseBooleanWriter 

     // **** seems buggy: headline "# type: sparse bool matrix\n" not read. 

     public OctaveSparseBoolean read(final BufferedReader reader) {

         final int nnz     = parseHeader("# nnz: ", 

                                         OctaveIO.readerReadLine(reader));

         final int rows    = parseHeader("# rows: ", 

                                         OctaveIO.readerReadLine(reader));

         final int columns = parseHeader("# columns: ", 

                                         OctaveIO.readerReadLine(reader));

         final OctaveSparseBoolean sparse = 

             new OctaveSparseBoolean(rows, columns, nnz);

         for (int n = 0; n < nnz; ++n) {

             final String line = OctaveIO.readerReadLine(reader);

             final String[] split = line.split(" ");

             if (split.length != 3) { // NOPMD 

                 throw new OctaveParseException("split.length != 3");

             }

             try {

                 final int row       = Integer.parseInt(split[0]);

                 final int column    = Integer.parseInt(split[1]);

                 final boolean value = StringUtil.parseBoolean(split[2]);

                 sparse.set(value, row, column);

             } catch (final NumberFormatException e) {

                 throw new OctaveParseException(e);

             }

         }

         return sparse;

     }

     private int parseHeader(final String prefix, final String line) {

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

             throw new OctaveParseException

                 ("Expected a line that should start with '" + prefix + 

                  "', got '" + line + "'");

         }

         try {

             return Integer.parseInt(line.substring(prefix.length()));

         } catch (final NumberFormatException e) {

             throw new OctaveParseException(e);

         }

     }

 }