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-rw-r--r--src/eu/siacs/conversations/utils/ExifHelper.java161
1 files changed, 161 insertions, 0 deletions
diff --git a/src/eu/siacs/conversations/utils/ExifHelper.java b/src/eu/siacs/conversations/utils/ExifHelper.java
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+++ b/src/eu/siacs/conversations/utils/ExifHelper.java
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+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package eu.siacs.conversations.utils;
+
+import android.util.Log;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+public class ExifHelper {
+ private static final String TAG = "CameraExif";
+
+ public static int getOrientation(InputStream is) {
+ if (is == null) {
+ return 0;
+ }
+
+ byte[] buf = new byte[8];
+ int length = 0;
+
+ // ISO/IEC 10918-1:1993(E)
+ while (read(is, buf, 2) && (buf[0] & 0xFF) == 0xFF) {
+ int marker = buf[1] & 0xFF;
+
+ // Check if the marker is a padding.
+ if (marker == 0xFF) {
+ continue;
+ }
+
+ // Check if the marker is SOI or TEM.
+ if (marker == 0xD8 || marker == 0x01) {
+ continue;
+ }
+ // Check if the marker is EOI or SOS.
+ if (marker == 0xD9 || marker == 0xDA) {
+ return 0;
+ }
+
+ // Get the length and check if it is reasonable.
+ if (!read(is, buf, 2)) {
+ return 0;
+ }
+ length = pack(buf, 0, 2, false);
+ if (length < 2) {
+ Log.e(TAG, "Invalid length");
+ return 0;
+ }
+ length -= 2;
+
+ // Break if the marker is EXIF in APP1.
+ if (marker == 0xE1 && length >= 6) {
+ if (!read(is, buf, 6)) return 0;
+ length -= 6;
+ if (pack(buf, 0, 4, false) == 0x45786966 &&
+ pack(buf, 4, 2, false) == 0) {
+ break;
+ }
+ }
+
+ // Skip other markers.
+ try {
+ is.skip(length);
+ } catch (IOException ex) {
+ return 0;
+ }
+ length = 0;
+ }
+
+ // JEITA CP-3451 Exif Version 2.2
+ if (length > 8) {
+ int offset = 0;
+ byte[] jpeg = new byte[length];
+ if (!read(is, jpeg, length)) {
+ return 0;
+ }
+
+ // Identify the byte order.
+ int tag = pack(jpeg, offset, 4, false);
+ if (tag != 0x49492A00 && tag != 0x4D4D002A) {
+ Log.e(TAG, "Invalid byte order");
+ return 0;
+ }
+ boolean littleEndian = (tag == 0x49492A00);
+
+ // Get the offset and check if it is reasonable.
+ int count = pack(jpeg, offset + 4, 4, littleEndian) + 2;
+ if (count < 10 || count > length) {
+ Log.e(TAG, "Invalid offset");
+ return 0;
+ }
+ offset += count;
+ length -= count;
+
+ // Get the count and go through all the elements.
+ count = pack(jpeg, offset - 2, 2, littleEndian);
+ while (count-- > 0 && length >= 12) {
+ // Get the tag and check if it is orientation.
+ tag = pack(jpeg, offset, 2, littleEndian);
+ if (tag == 0x0112) {
+ // We do not really care about type and count, do we?
+ int orientation = pack(jpeg, offset + 8, 2, littleEndian);
+ switch (orientation) {
+ case 1:
+ return 0;
+ case 3:
+ return 180;
+ case 6:
+ return 90;
+ case 8:
+ return 270;
+ }
+ Log.i(TAG, "Unsupported orientation");
+ return 0;
+ }
+ offset += 12;
+ length -= 12;
+ }
+ }
+
+ Log.i(TAG, "Orientation not found");
+ return 0;
+ }
+
+ private static int pack(byte[] bytes, int offset, int length,
+ boolean littleEndian) {
+ int step = 1;
+ if (littleEndian) {
+ offset += length - 1;
+ step = -1;
+ }
+
+ int value = 0;
+ while (length-- > 0) {
+ value = (value << 8) | (bytes[offset] & 0xFF);
+ offset += step;
+ }
+ return value;
+ }
+
+ private static boolean read(InputStream is, byte[] buf, int length) {
+ try {
+ return is.read(buf, 0, length) == length;
+ } catch (IOException ex) {
+ return false;
+ }
+ }
+}