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.usbtuner;
18 
19 import android.util.Log;
20 
21 import com.android.usbtuner.data.Channel;
22 
23 import java.io.BufferedReader;
24 import java.io.IOException;
25 import java.io.InputStream;
26 import java.io.InputStreamReader;
27 import java.util.ArrayList;
28 import java.util.List;
29 
30 /**
31  * Parses plain text formatted scan files, which contain the list of channels.
32  */
33 public class ChannelScanFileParser {
34     private static final String TAG = "ChannelScanFileParser";
35 
36     public static final class ScanChannel {
37         public final int type;
38         public final int frequency;
39         public final String modulation;
40         public final String filename;
41 
forTuner(int frequency, String modulation)42         public static ScanChannel forTuner(int frequency, String modulation) {
43             return new ScanChannel(Channel.TYPE_TUNER, frequency, modulation, null);
44         }
45 
forFile(int frequency, String filename)46         public static ScanChannel forFile(int frequency, String filename) {
47             return new ScanChannel(Channel.TYPE_FILE, frequency, "file:", filename);
48         }
49 
ScanChannel(int type, int frequency, String modulation, String filename)50         private ScanChannel(int type, int frequency, String modulation, String filename) {
51             this.type = type;
52             this.frequency = frequency;
53             this.modulation = modulation;
54             this.filename = filename;
55         }
56     }
57 
58     /**
59      * Parses a given scan file and returns the list of {@link ScanChannel} objects.
60      *
61      * @param is {@link InputStream} of a scan file. Each line matches one channel.
62      *           The line format of the scan file is as follows:<br>
63      *           "A &lt;frequency&gt; &lt;modulation&gt;".
64      * @return a list of {@link ScanChannel} objects parsed
65      */
parseScanFile(InputStream is)66     public static List<ScanChannel> parseScanFile(InputStream is) {
67         BufferedReader in = new BufferedReader(new InputStreamReader(is));
68         String line;
69         List<ScanChannel> scanChannelList = new ArrayList<>();
70         try {
71             while ((line = in.readLine()) != null) {
72                 if (line.isEmpty()) {
73                     continue;
74                 }
75                 if (line.charAt(0) == '#') {
76                     // Skip comment line
77                     continue;
78                 }
79                 String[] tokens = line.split("\\s+");
80                 if (tokens.length != 3) {
81                     continue;
82                 }
83                 if (!tokens[0].equals("A")) {
84                     // Only support ATSC
85                     continue;
86                 }
87                 scanChannelList.add(ScanChannel.forTuner(Integer.parseInt(tokens[1]), tokens[2]));
88             }
89         } catch (IOException e) {
90             Log.e(TAG, "error on parseScanFile()", e);
91         }
92         return scanChannelList;
93     }
94 }
95