From 91833f3d909c5b01dc590289c1a8dab9e145318a Mon Sep 17 00:00:00 2001
From: Earl Ou <shunhsingou@google.com>
Date: Wed, 7 Nov 2012 15:28:48 +0800
Subject: use ExifParser to parse the orientaion

Change-Id: I47171c028cbc1f94b7de5d067de0636a9e241fbb
---
 src/com/android/gallery3d/data/Exif.java | 161 +++++++------------------------
 1 file changed, 36 insertions(+), 125 deletions(-)

diff --git a/src/com/android/gallery3d/data/Exif.java b/src/com/android/gallery3d/data/Exif.java
index ba5862a86..4d1fc9453 100644
--- a/src/com/android/gallery3d/data/Exif.java
+++ b/src/com/android/gallery3d/data/Exif.java
@@ -18,144 +18,55 @@ package com.android.gallery3d.data;
 
 import android.util.Log;
 
+import com.android.gallery3d.exif.ExifInvalidFormatException;
+import com.android.gallery3d.exif.ExifParser;
+import com.android.gallery3d.exif.ExifTag;
+
 import java.io.IOException;
 import java.io.InputStream;
 
 public class Exif {
-    private static final String TAG = "CameraExif";
+    private static final String TAG = "GalleryExif";
 
     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;
+        try {
+            ExifParser parser = ExifParser.parse(is, ExifParser.OPTION_IFD_0);
+            int event = parser.next();
+            while (event != ExifParser.EVENT_END) {
+                if (event == ExifParser.EVENT_NEW_TAG) {
+                    ExifTag tag = parser.getTag();
+                    if (tag.getTagId() == ExifTag.TAG_ORIENTATION &&
+                            tag.hasValue()) {
+                        int orient = tag.getUnsignedShort(0);
+                        switch (orient) {
+                            case ExifTag.Orientation.TOP_LEFT:
+                                return 0;
+                            case ExifTag.Orientation.BOTTOM_LEFT:
+                                return 180;
+                            case ExifTag.Orientation.RIGHT_TOP:
+                                return 90;
+                            case ExifTag.Orientation.RIGHT_BOTTOM:
+                                return 270;
+                            default:
+                                Log.i(TAG, "Unsupported orientation");
+                                return 0;
+                        }
                     }
-                    Log.i(TAG, "Unsupported orientation");
-                    return 0;
                 }
-                offset += 12;
-                length -= 12;
+                event = parser.next();
             }
-        }
-
-        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;
+            Log.i(TAG, "Orientation not found");
+            return 0;
+        } catch (IOException e) {
+            Log.w(TAG, "Failed to read EXIF orientation", e);
+            return 0;
+        } catch (ExifInvalidFormatException e) {
+            Log.w(TAG, "Failed to read EXIF orientation", e);
+            return 0;
         }
     }
 }
-- 
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