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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.tv.tuner;
     18 
     19 import android.util.Log;
     20 import com.android.tv.tuner.data.nano.Channel;
     21 import java.io.BufferedReader;
     22 import java.io.IOException;
     23 import java.io.InputStream;
     24 import java.io.InputStreamReader;
     25 import java.util.ArrayList;
     26 import java.util.List;
     27 
     28 /** Parses plain text formatted scan files, which contain the list of channels. */
     29 public class ChannelScanFileParser {
     30     private static final String TAG = "ChannelScanFileParser";
     31 
     32     public static final class ScanChannel {
     33         public final int type;
     34         public final int frequency;
     35         public final String modulation;
     36         public final String filename;
     37         /**
     38          * Radio frequency (channel) number specified at
     39          * https://en.wikipedia.org/wiki/North_American_television_frequencies This can be {@code
     40          * null} for cases like cable signal.
     41          */
     42         public final Integer radioFrequencyNumber;
     43 
     44         public static ScanChannel forTuner(
     45                 int frequency, String modulation, Integer radioFrequencyNumber) {
     46             return new ScanChannel(
     47                     Channel.TunerType.TYPE_TUNER,
     48                     frequency,
     49                     modulation,
     50                     null,
     51                     radioFrequencyNumber);
     52         }
     53 
     54         public static ScanChannel forFile(int frequency, String filename) {
     55             return new ScanChannel(Channel.TunerType.TYPE_FILE, frequency, "file:", filename, null);
     56         }
     57 
     58         private ScanChannel(
     59                 int type,
     60                 int frequency,
     61                 String modulation,
     62                 String filename,
     63                 Integer radioFrequencyNumber) {
     64             this.type = type;
     65             this.frequency = frequency;
     66             this.modulation = modulation;
     67             this.filename = filename;
     68             this.radioFrequencyNumber = radioFrequencyNumber;
     69         }
     70     }
     71 
     72     /**
     73      * Parses a given scan file and returns the list of {@link ScanChannel} objects.
     74      *
     75      * @param is {@link InputStream} of a scan file. Each line matches one channel. The line format
     76      *     of the scan file is as follows:<br>
     77      *     "A &lt;frequency&gt; &lt;modulation&gt;".
     78      * @return a list of {@link ScanChannel} objects parsed
     79      */
     80     public static List<ScanChannel> parseScanFile(InputStream is) {
     81         BufferedReader in = new BufferedReader(new InputStreamReader(is));
     82         String line;
     83         List<ScanChannel> scanChannelList = new ArrayList<>();
     84         try {
     85             while ((line = in.readLine()) != null) {
     86                 if (line.isEmpty()) {
     87                     continue;
     88                 }
     89                 if (line.charAt(0) == '#') {
     90                     // Skip comment line
     91                     continue;
     92                 }
     93                 String[] tokens = line.split("\\s+");
     94                 if (tokens.length != 3 && tokens.length != 4) {
     95                     continue;
     96                 }
     97                 scanChannelList.add(
     98                         ScanChannel.forTuner(
     99                                 Integer.parseInt(tokens[1]),
    100                                 tokens[2],
    101                                 tokens.length == 4 ? Integer.parseInt(tokens[3]) : null));
    102             }
    103         } catch (IOException e) {
    104             Log.e(TAG, "error on parseScanFile()", e);
    105         }
    106         return scanChannelList;
    107     }
    108 }
    109