Fix function ComputeChiSquared (issue tesseract-ocr#3925)

mftraining crashed if the search did not find anything. Signed-off-by: Stefan Weil <sw@weilnetz.de>
GerHobbelt · Jan 27, 2023 · 071ddfe · 071ddfe
1 parent 295d7e2
commit 071ddfe
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/src/classify/cluster.cpp b/src/classify/cluster.cpp
@@ -2774,8 +2774,8 @@ static double ComputeChiSquared(uint16_t DegreesOfFreedom, double Alpha)
    for the specified number of degrees of freedom.  Search the list for
    the desired chi-squared. */
   CHISTRUCT SearchKey(0.0, Alpha);
-  auto OldChiSquared = reinterpret_cast<CHISTRUCT *>(
-      search(ChiWith[DegreesOfFreedom], &SearchKey, AlphaMatch)->first_node());
+  auto *found = search(ChiWith[DegreesOfFreedom], &SearchKey, AlphaMatch);
+  auto OldChiSquared = reinterpret_cast<CHISTRUCT *>(found ? found->first_node() : nullptr);
 
   if (OldChiSquared == nullptr) {
     OldChiSquared = new CHISTRUCT(DegreesOfFreedom, Alpha);