fixed e3a2be37 from https://gitee.com/fang-yunzhong/third_party_jsoncpp/pulls/28

Add boundary check to avoid cross the border
Signed-off-by: Nfangyunzhong <fangyunzhong2@huawei.com>

src/lib_json/json_reader.cpp

@@ -772,6 +772,10 @@ void Reader::getLocationLineAndColumn(Location location, int& line,
   while (current < location && current != end_) {
     Char c = *current++;
     if (c == '\r') {
+      // Add boundary check to avoid cross the border
+      if (current == end_) {
+        break;
+      }
       if (*current == '\n')
         ++current;
       lastLineStart = current;
@@ -1838,6 +1842,10 @@ void OurReader::getLocationLineAndColumn(Location location, int& line,
   while (current < location && current != end_) {
     Char c = *current++;
     if (c == '\r') {
+      // Add boundary check to avoid cross the border
+      if (current == end_) {
+        break;
+      }
       if (*current == '\n')
         ++current;
       lastLineStart = current;