X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=core%2Fsrc%2Fcom%2Fgoogle%2Fzxing%2Fqrcode%2FQRCodeReader.java;h=2a12c6dd3e14c61f1dc6ca94476e173b3292a209;hb=d0920ceb07da310eb8e10f6a11d5590bcb3184ea;hp=575af1f4018f4d4883ec83be1f4c8b94c0c0de6d;hpb=48a784144880eab9f726f030bdce41cca1ff8870;p=zxing.git

diff --git a/core/src/com/google/zxing/qrcode/QRCodeReader.java b/core/src/com/google/zxing/qrcode/QRCodeReader.java
index 575af1f4..2a12c6dd 100644
--- a/core/src/com/google/zxing/qrcode/QRCodeReader.java
+++ b/core/src/com/google/zxing/qrcode/QRCodeReader.java
@@ -118,6 +118,9 @@ public class QRCodeReader implements Reader {
     }
 
     int moduleSize = x - leftTopBlack[0];
+    if (moduleSize == 0) {
+      throw NotFoundException.getNotFoundInstance();
+    }
 
     // And now find where the rightmost black module on the first row ends
     int rowEndOfSymbol = width - 1;
@@ -137,9 +140,10 @@ public class QRCodeReader implements Reader {
 
     // Push in the "border" by half the module width so that we start
     // sampling in the middle of the module. Just in case the image is a
-    // little off, this will help recover.
-    x -= moduleSize >> 1;
-    y -= moduleSize >> 1;
+    // little off, this will help recover. Need to back up at least 1.
+    int backOffAmount = moduleSize == 1 ? 1 : moduleSize >> 1;
+    x -= backOffAmount;
+    y -= backOffAmount;
 
     if ((x + (dimension - 1) * moduleSize) >= width ||
         (y + (dimension - 1) * moduleSize) >= height) {
@@ -159,4 +163,4 @@ public class QRCodeReader implements Reader {
     return bits;
   }
 
-}
\ No newline at end of file
+}