1 files changed, 11 insertions, 0 deletions
diff --git a/core/fpdfdoc/cpvt_wordrange.h b/core/fpdfdoc/cpvt_wordrange.h
index ed06d6f0de..638f6c17c0 100644
--- a/core/fpdfdoc/cpvt_wordrange.h
+++ b/core/fpdfdoc/cpvt_wordrange.h
@@ -7,6 +7,7 @@
 #ifndef CORE_FPDFDOC_CPVT_WORDRANGE_H_
 #define CORE_FPDFDOC_CPVT_WORDRANGE_H_
 
+#include <algorithm>
 #include <utility>
 
 #include "core/fpdfdoc/cpvt_wordplace.h"
@@ -41,6 +42,16 @@ struct CPVT_WordRange {
     Normalize();
   }
 
+  CPVT_WordRange Intersect(const CPVT_WordRange& that) const {
+    if (that.EndPos < BeginPos || that.BeginPos > EndPos ||
+        EndPos < that.BeginPos || BeginPos > that.EndPos) {
+      return CPVT_WordRange();
+    }
+
+    return CPVT_WordRange(std::max(BeginPos, that.BeginPos),
+                          std::min(EndPos, that.EndPos));
+  }
+
   inline bool IsEmpty() const { return BeginPos == EndPos; }
   inline bool operator==(const CPVT_WordRange& wr) const {
     return wr.BeginPos == BeginPos && wr.EndPos == EndPos;