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 */
16package com.android.browser;
17
18import java.net.MalformedURLException;
19
20import libcore.io.Base64;
21
22/**
23 * Class extracts the mime type and data from a data uri.
24 * A data URI is of the form:
25 * <pre>
26 * data:[&lt;MIME-type&gt;][;charset=&lt;encoding&gt;][;base64],&lt;data&gt;
27 * </pre>
28 */
29public class DataUri {
30    private static final String DATA_URI_PREFIX = "data:";
31    private static final String BASE_64_ENCODING = ";base64";
32
33    private String mMimeType;
34    private byte[] mData;
35
36    public DataUri(String uri) throws MalformedURLException {
37        if (!isDataUri(uri)) {
38            throw new MalformedURLException("Not a data URI");
39        }
40
41        int commaIndex = uri.indexOf(',', DATA_URI_PREFIX.length());
42        if (commaIndex < 0) {
43            throw new MalformedURLException("Comma expected in data URI");
44        }
45        String contentType = uri.substring(DATA_URI_PREFIX.length(),
46                commaIndex);
47        mData = uri.substring(commaIndex + 1).getBytes();
48        if (contentType.contains(BASE_64_ENCODING)) {
49            mData = Base64.decode(mData);
50        }
51        int semiIndex = contentType.indexOf(';');
52        if (semiIndex > 0) {
53            mMimeType = contentType.substring(0, semiIndex);
54        } else {
55            mMimeType = contentType;
56        }
57    }
58
59    /**
60     * Returns true if the text passed in appears to be a data URI.
61     */
62    public static boolean isDataUri(String text)
63    {
64        return text.startsWith(DATA_URI_PREFIX);
65    }
66
67    public String getMimeType() {
68        return mMimeType;
69    }
70
71    public byte[] getData() {
72        return mData;
73    }
74}
75