1 files changed, 11 insertions, 0 deletions
diff --git a/src/com/android/dreams/phototable/PhotoSource.java b/src/com/android/dreams/phototable/PhotoSource.java
index 670bd02..32d41c7 100644
--- a/src/com/android/dreams/phototable/PhotoSource.java
+++ b/src/com/android/dreams/phototable/PhotoSource.java
@@ -43,6 +43,9 @@ public abstract class PhotoSource {
     private static final String TAG = "PhotoTable.PhotoSource";
     private static final boolean DEBUG = false;
 
+    // An invalid cursor position to represent the uninitialized state.
+    protected static final int INVALID = -2;
+
     // This should be large enough for BitmapFactory to decode the header so
     // that we can mark and reset the input stream to avoid duplicate network i/o
     private static final int BUFFER_SIZE = 128 * 1024;
@@ -248,6 +251,14 @@ public abstract class PhotoSource {
         }
     }
 
+    protected int pickRandomStart(int total, int max) {
+        if (max >= total) {
+            return -1;
+        } else {
+            return (mRNG.nextInt() % (total - max)) - 1;
+        }
+    }
+
     protected abstract InputStream getStream(ImageData data, int longSide);
     protected abstract Collection<ImageData> findImages(int howMany);
     public abstract Collection<AlbumData> findAlbums();