Fix bug in UTF-16 checker returning wrong offset for missing low surrogate.

git-svn-id: svn://vcs.exim.org/pcre2/code/trunk@1226 6239d852-aaf2-0410-a92c-79f79f948069

1 files changed, 2 insertions, 2 deletions

diff --git a/src/pcre2_valid_utf.c b/src/pcre2_valid_utf.c
index 96e8bff..e47ea78 100644
--- a/src/pcre2_valid_utf.c
+++ b/src/pcre2_valid_utf.c
@@ -7,7 +7,7 @@ and semantics are as close as possible to those of the Perl 5 language.
 
                        Written by Philip Hazel
      Original API code Copyright (c) 1997-2012 University of Cambridge
-          New API code Copyright (c) 2016-2017 University of Cambridge
+          New API code Copyright (c) 2016-2020 University of Cambridge
 
 -----------------------------------------------------------------------------
 Redistribution and use in source and binary forms, with or without
@@ -347,7 +347,7 @@ for (p = string; length > 0; p++)
     length--;
     if ((*p & 0xfc00) != 0xdc00)
       {
-      *erroroffset = p - string;
+      *erroroffset = p - string - 1;
       return PCRE2_ERROR_UTF16_ERR2;
       }
     }