Fix for https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=38913

1 files changed, 3 insertions, 2 deletions

diff --git a/core/src/main/java/com/google/zxing/common/reedsolomon/ReedSolomonDecoder.java b/core/src/main/java/com/google/zxing/common/reedsolomon/ReedSolomonDecoder.java
index e406e2f00..259345657 100644
--- a/core/src/main/java/com/google/zxing/common/reedsolomon/ReedSolomonDecoder.java
+++ b/core/src/main/java/com/google/zxing/common/reedsolomon/ReedSolomonDecoder.java
@@ -100,7 +100,7 @@ public final class ReedSolomonDecoder {
     GenericGFPoly t = field.getOne();
 
     // Run Euclidean algorithm until r's degree is less than R/2
-    while (r.getDegree() >= R / 2) {
+    while (2 * r.getDegree() >= R) {
       GenericGFPoly rLastLast = rLast;
       GenericGFPoly tLastLast = tLast;
       rLast = r;
@@ -125,7 +125,8 @@ public final class ReedSolomonDecoder {
       t = q.multiply(tLast).addOrSubtract(tLastLast);
 
       if (r.getDegree() >= rLast.getDegree()) {
-        throw new IllegalStateException("Division algorithm failed to reduce polynomial?");
+        throw new IllegalStateException("Division algorithm failed to reduce polynomial? " +
+          "r: " + r + ", rLast: " + rLast);
       }
     }