HdmiUtils.java revision 0340bbc89f8162f9c2a298c98b03bfcdd1bc6e87 
1/*
2 * Copyright (C) 2014 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
17package com.android.server.hdmi;
18
19import android.hardware.hdmi.HdmiCec;
20import android.hardware.hdmi.HdmiCecMessage;
21import android.util.Slog;
22
23import java.util.ArrayList;
24import java.util.Collections;
25import java.util.List;
26
27/**
28 * Various utilities to handle HDMI CEC messages.
29 */
30final class HdmiUtils {
31
32    private HdmiUtils() { /* cannot be instantiated */ }
33
34    /**
35     * Verify if the given address is for the given device type.  If not it will throw
36     * {@link IllegalArgumentException}.
37     *
38     * @param logicalAddress the logical address to verify
39     * @param deviceType the device type to check
40     * @throw IllegalArgumentException
41     */
42    static void verifyAddressType(int logicalAddress, int deviceType) {
43        int actualDeviceType = HdmiCec.getTypeFromAddress(logicalAddress);
44        if (actualDeviceType != deviceType) {
45            throw new IllegalArgumentException("Device type missmatch:[Expected:" + deviceType
46                    + ", Actual:" + actualDeviceType);
47        }
48    }
49
50    /**
51     * Check if the given CEC message come from the given address.
52     *
53     * @param cmd the CEC message to check
54     * @param expectedAddress the expected source address of the given message
55     * @param tag the tag of caller module (for log message)
56     * @return true if the CEC message comes from the given address
57     */
58    static boolean checkCommandSource(HdmiCecMessage cmd, int expectedAddress, String tag) {
59        int src = cmd.getSource();
60        if (src != expectedAddress) {
61            Slog.w(tag, "Invalid source [Expected:" + expectedAddress + ", Actual:" + src + "]");
62            return false;
63        }
64        return true;
65    }
66
67    /**
68     * Parse the parameter block of CEC message as [System Audio Status].
69     *
70     * @param cmd the CEC message to parse
71     * @return true if the given parameter has [ON] value
72     */
73    static boolean parseCommandParamSystemAudioStatus(HdmiCecMessage cmd) {
74        // TODO: Handle the exception when the length is wrong.
75        return cmd.getParams().length > 0
76                && cmd.getParams()[0] == HdmiConstants.SYSTEM_AUDIO_STATUS_ON;
77    }
78
79    /**
80     * Convert integer array to list of {@link Integer}.
81     *
82     * <p>The result is immutable.
83     *
84     * @param is integer array
85     * @return {@link List} instance containing the elements in the given array
86     */
87    static List<Integer> asImmutableList(final int[] is) {
88        ArrayList<Integer> list = new ArrayList<>(is.length);
89        for (int type : is) {
90            list.add(type);
91        }
92        return Collections.unmodifiableList(list);
93    }
94
95    /**
96     * Assemble two bytes into single integer value.
97     *
98     * @param data to be assembled
99     * @return assembled value
100     */
101    static int twoBytesToInt(byte[] data) {
102        return ((data[0] & 0xFF) << 8) | (data[1] & 0xFF);
103    }
104
105    /**
106     * Assemble three bytes into single integer value.
107     *
108     * @param data to be assembled
109     * @return assembled value
110     */
111    static int threeBytesToInt(byte[] data) {
112        return ((data[0] & 0xFF) << 16) | ((data[1] & 0xFF) << 8) | (data[2] & 0xFF);
113    }
114}
115