1/*
2 * Copyright (C) 2010 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 android.nfc.tech;
18
19import android.nfc.Tag;
20import android.os.Bundle;
21import android.os.RemoteException;
22
23import java.io.IOException;
24
25/**
26 * Provides access to NFC-V (ISO 15693) properties and I/O operations on a {@link Tag}.
27 *
28 * <p>Acquire a {@link NfcV} object using {@link #get}.
29 * <p>The primary NFC-V I/O operation is {@link #transceive}. Applications must
30 * implement their own protocol stack on top of {@link #transceive}.
31 *
32 * <p class="note"><strong>Note:</strong> Methods that perform I/O operations
33 * require the {@link android.Manifest.permission#NFC} permission.
34 */
35public final class NfcV extends BasicTagTechnology {
36    /** @hide */
37    public static final String EXTRA_RESP_FLAGS = "respflags";
38
39    /** @hide */
40    public static final String EXTRA_DSFID = "dsfid";
41
42    private byte mRespFlags;
43    private byte mDsfId;
44
45    /**
46     * Get an instance of {@link NfcV} for the given tag.
47     * <p>Returns null if {@link NfcV} was not enumerated in {@link Tag#getTechList}.
48     * This indicates the tag does not support NFC-V.
49     * <p>Does not cause any RF activity and does not block.
50     *
51     * @param tag an NFC-V compatible tag
52     * @return NFC-V object
53     */
54    public static NfcV get(Tag tag) {
55        if (!tag.hasTech(TagTechnology.NFC_V)) return null;
56        try {
57            return new NfcV(tag);
58        } catch (RemoteException e) {
59            return null;
60        }
61    }
62
63    /** @hide */
64    public NfcV(Tag tag) throws RemoteException {
65        super(tag, TagTechnology.NFC_V);
66        Bundle extras = tag.getTechExtras(TagTechnology.NFC_V);
67        mRespFlags = extras.getByte(EXTRA_RESP_FLAGS);
68        mDsfId = extras.getByte(EXTRA_DSFID);
69    }
70
71    /**
72     * Return the Response Flag bytes from tag discovery.
73     *
74     * <p>Does not cause any RF activity and does not block.
75     *
76     * @return Response Flag bytes
77     */
78    public byte getResponseFlags() {
79        return mRespFlags;
80    }
81
82    /**
83     * Return the DSF ID bytes from tag discovery.
84     *
85     * <p>Does not cause any RF activity and does not block.
86     *
87     * @return DSF ID bytes
88     */
89    public byte getDsfId() {
90        return mDsfId;
91    }
92
93    /**
94     * Send raw NFC-V commands to the tag and receive the response.
95     *
96     * <p>Applications must not append the CRC to the payload,
97     * it will be automatically calculated. The application does
98     * provide FLAGS, CMD and PARAMETER bytes.
99     *
100     * <p>Use {@link #getMaxTransceiveLength} to retrieve the maximum amount of bytes
101     * that can be sent with {@link #transceive}.
102     *
103     * <p>This is an I/O operation and will block until complete. It must
104     * not be called from the main application thread. A blocked call will be canceled with
105     * {@link IOException} if {@link #close} is called from another thread.
106     *
107     * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
108     *
109     * @param data bytes to send
110     * @return bytes received in response
111     * @throws TagLostException if the tag leaves the field
112     * @throws IOException if there is an I/O failure, or this operation is canceled
113     */
114    public byte[] transceive(byte[] data) throws IOException {
115        return transceive(data, true);
116    }
117
118
119    /**
120     * Return the maximum number of bytes that can be sent with {@link #transceive}.
121     * @return the maximum number of bytes that can be sent with {@link #transceive}.
122     */
123    public int getMaxTransceiveLength() {
124        return getMaxTransceiveLengthInternal();
125    }
126}
127