1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/mobile/android/base/favicons/decoders/FaviconDecoder.java Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,240 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +package org.mozilla.gecko.favicons.decoders;
1.9 +
1.10 +import android.graphics.Bitmap;
1.11 +import android.util.Base64;
1.12 +import android.util.Log;
1.13 +
1.14 +import org.mozilla.gecko.gfx.BitmapUtils;
1.15 +
1.16 +import java.util.Iterator;
1.17 +import java.util.NoSuchElementException;
1.18 +
1.19 +/**
1.20 + * Class providing static utility methods for decoding favicons.
1.21 + */
1.22 +public class FaviconDecoder {
1.23 + private static final String LOG_TAG = "GeckoFaviconDecoder";
1.24 +
1.25 + static enum ImageMagicNumbers {
1.26 + // It is irritating that Java bytes are signed...
1.27 + PNG(new byte[] {(byte) (0x89 & 0xFF), 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a}),
1.28 + GIF(new byte[] {0x47, 0x49, 0x46, 0x38}),
1.29 + JPEG(new byte[] {-0x1, -0x28, -0x1, -0x20}),
1.30 + BMP(new byte[] {0x42, 0x4d}),
1.31 + WEB(new byte[] {0x57, 0x45, 0x42, 0x50, 0x0a});
1.32 +
1.33 + public byte[] value;
1.34 +
1.35 + private ImageMagicNumbers(byte[] value) {
1.36 + this.value = value;
1.37 + }
1.38 + }
1.39 +
1.40 + /**
1.41 + * Check for image format magic numbers of formats supported by Android.
1.42 + * @param buffer Byte buffer to check for magic numbers
1.43 + * @param offset Offset at which to look for magic numbers.
1.44 + * @return true if the buffer contains a bitmap decodable by Android (Or at least, a sequence
1.45 + * starting with the magic numbers thereof). false otherwise.
1.46 + */
1.47 + private static boolean isDecodableByAndroid(byte[] buffer, int offset) {
1.48 + for (ImageMagicNumbers m : ImageMagicNumbers.values()) {
1.49 + if (bufferStartsWith(buffer, m.value, offset)) {
1.50 + return true;
1.51 + }
1.52 + }
1.53 +
1.54 + return false;
1.55 + }
1.56 +
1.57 + /**
1.58 + * Utility function to check for the existence of a test byte sequence at a given offset in a
1.59 + * buffer.
1.60 + *
1.61 + * @param buffer Byte buffer to search.
1.62 + * @param test Byte sequence to search for.
1.63 + * @param bufferOffset Index in input buffer to expect test sequence.
1.64 + * @return true if buffer contains the byte sequence given in test at offset bufferOffset, false
1.65 + * otherwise.
1.66 + */
1.67 + static boolean bufferStartsWith(byte[] buffer, byte[] test, int bufferOffset) {
1.68 + if (buffer.length < test.length) {
1.69 + return false;
1.70 + }
1.71 +
1.72 + for (int i = 0; i < test.length; ++i) {
1.73 + if (buffer[bufferOffset + i] != test[i]) {
1.74 + return false;
1.75 + }
1.76 + }
1.77 + return true;
1.78 + }
1.79 +
1.80 + /**
1.81 + * Decode the favicon present in the region of the provided byte[] starting at offset and
1.82 + * proceeding for length bytes, if any. Returns either the resulting LoadFaviconResult or null if the
1.83 + * given range does not contain a bitmap we know how to decode.
1.84 + *
1.85 + * @param buffer Byte array containing the favicon to decode.
1.86 + * @param offset The index of the first byte in the array of the region of interest.
1.87 + * @param length The length of the region in the array to decode.
1.88 + * @return The decoded version of the bitmap in the described region, or null if none can be
1.89 + * decoded.
1.90 + */
1.91 + public static LoadFaviconResult decodeFavicon(byte[] buffer, int offset, int length) {
1.92 + LoadFaviconResult result;
1.93 + if (isDecodableByAndroid(buffer, offset)) {
1.94 + result = new LoadFaviconResult();
1.95 + result.offset = offset;
1.96 + result.length = length;
1.97 + result.isICO = false;
1.98 +
1.99 + Bitmap decodedImage = BitmapUtils.decodeByteArray(buffer, offset, length);
1.100 + if (decodedImage == null) {
1.101 + // What we got wasn't decodable after all. Probably corrupted image, or we got a muffled OOM.
1.102 + return null;
1.103 + }
1.104 +
1.105 + // We assume here that decodeByteArray doesn't hold on to the entire supplied
1.106 + // buffer -- worst case, each of our buffers will be twice the necessary size.
1.107 + result.bitmapsDecoded = new SingleBitmapIterator(decodedImage);
1.108 + result.faviconBytes = buffer;
1.109 +
1.110 + return result;
1.111 + }
1.112 +
1.113 + // If it's not decodable by Android, it might be an ICO. Let's try.
1.114 + ICODecoder decoder = new ICODecoder(buffer, offset, length);
1.115 +
1.116 + result = decoder.decode();
1.117 +
1.118 + if (result == null) {
1.119 + return null;
1.120 + }
1.121 +
1.122 + return result;
1.123 + }
1.124 +
1.125 + public static LoadFaviconResult decodeDataURI(String uri) {
1.126 + if (uri == null) {
1.127 + Log.w(LOG_TAG, "Can't decode null data: URI.");
1.128 + return null;
1.129 + }
1.130 +
1.131 + if (!uri.startsWith("data:image/")) {
1.132 + Log.w(LOG_TAG, "Can't decode non-image data: URI.");
1.133 + return null;
1.134 + }
1.135 +
1.136 + // Otherwise, let's attack this blindly. Strictly we should be parsing.
1.137 + int offset = uri.indexOf(',') + 1;
1.138 + if (offset == 0) {
1.139 + Log.w(LOG_TAG, "No ',' in data: URI; malformed?");
1.140 + return null;
1.141 + }
1.142 +
1.143 + try {
1.144 + String base64 = uri.substring(offset);
1.145 + byte[] raw = Base64.decode(base64, Base64.DEFAULT);
1.146 + return decodeFavicon(raw);
1.147 + } catch (Exception e) {
1.148 + Log.w(LOG_TAG, "Couldn't decode data: URI.", e);
1.149 + return null;
1.150 + }
1.151 + }
1.152 +
1.153 + public static LoadFaviconResult decodeFavicon(byte[] buffer) {
1.154 + return decodeFavicon(buffer, 0, buffer.length);
1.155 + }
1.156 +
1.157 + /**
1.158 + * Returns the smallest bitmap in the icon represented by the provided
1.159 + * data: URI that's larger than the desired width, or the largest if
1.160 + * there is no larger icon.
1.161 + *
1.162 + * Returns null if no bitmap could be extracted.
1.163 + *
1.164 + * Bug 961600: we shouldn't be doing all of this work. The favicon cache
1.165 + * should be used, and will give us the right size icon.
1.166 + */
1.167 + public static Bitmap getMostSuitableBitmapFromDataURI(String iconURI, int desiredWidth) {
1.168 + LoadFaviconResult result = FaviconDecoder.decodeDataURI(iconURI);
1.169 + if (result == null) {
1.170 + // Nothing we can do.
1.171 + Log.w(LOG_TAG, "Unable to decode icon URI.");
1.172 + return null;
1.173 + }
1.174 +
1.175 + final Iterator<Bitmap> bitmaps = result.getBitmaps();
1.176 + if (!bitmaps.hasNext()) {
1.177 + Log.w(LOG_TAG, "No bitmaps in decoded icon.");
1.178 + return null;
1.179 + }
1.180 +
1.181 + Bitmap bitmap = bitmaps.next();
1.182 + if (!bitmaps.hasNext()) {
1.183 + // We're done! There was only one, so this is as big as it gets.
1.184 + return bitmap;
1.185 + }
1.186 +
1.187 + // Find a bitmap of the most suitable size.
1.188 + int currentWidth = bitmap.getWidth();
1.189 + while ((currentWidth < desiredWidth) &&
1.190 + bitmaps.hasNext()) {
1.191 + final Bitmap b = bitmaps.next();
1.192 + if (b.getWidth() > currentWidth) {
1.193 + currentWidth = b.getWidth();
1.194 + bitmap = b;
1.195 + }
1.196 + }
1.197 +
1.198 + return bitmap;
1.199 + }
1.200 +
1.201 + /**
1.202 + * Iterator to hold a single bitmap.
1.203 + */
1.204 + static class SingleBitmapIterator implements Iterator<Bitmap> {
1.205 + private Bitmap bitmap;
1.206 +
1.207 + public SingleBitmapIterator(Bitmap b) {
1.208 + bitmap = b;
1.209 + }
1.210 +
1.211 + /**
1.212 + * Slightly cheating here - this iterator supports peeking (Handy in a couple of obscure
1.213 + * places where the runtime type of the Iterator under consideration is known and
1.214 + * destruction of it is discouraged.
1.215 + *
1.216 + * @return The bitmap carried by this SingleBitmapIterator.
1.217 + */
1.218 + public Bitmap peek() {
1.219 + return bitmap;
1.220 + }
1.221 +
1.222 + @Override
1.223 + public boolean hasNext() {
1.224 + return bitmap != null;
1.225 + }
1.226 +
1.227 + @Override
1.228 + public Bitmap next() {
1.229 + if (bitmap == null) {
1.230 + throw new NoSuchElementException("Element already returned from SingleBitmapIterator.");
1.231 + }
1.232 +
1.233 + Bitmap ret = bitmap;
1.234 + bitmap = null;
1.235 + return ret;
1.236 + }
1.237 +
1.238 + @Override
1.239 + public void remove() {
1.240 + throw new UnsupportedOperationException("remove() not supported on SingleBitmapIterator.");
1.241 + }
1.242 + }
1.243 +}
