From bfb893170e25b030a12a48bea5c0d92d1248b082 Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Thu, 22 Jun 2017 15:51:49 +0200
Subject: [PATCH] Fix initialization of SingleCharBuffer and Utf16CharBuffer
 data

Don't do it at all in the ctor, initializing just the first element of
the array is useless as it's overwritten by EncodeChar() anyhow, so just
leave the task of NUL-terminating the data to this function as well.

It might be even better to just have a ctor taking wxUniChar in these
classes instead and make EncodeChar() a trivial wrapper around it, but
for now just apply the minimal fix to repair the test breakage after the
last commit.

See https://github.com/wxWidgets/wxWidgets/pull/467#issuecomment-310384946
---
 include/wx/stringops.h   | 17 +++--------------
 src/common/stringops.cpp |  2 ++
 2 files changed, 5 insertions(+), 14 deletions(-)

diff --git a/include/wx/stringops.h b/include/wx/stringops.h
index c627c8c7b7..150554f341 100644
--- a/include/wx/stringops.h
+++ b/include/wx/stringops.h
@@ -48,14 +48,8 @@ struct WXDLLIMPEXP_BASE wxStringOperationsWchar
     // encodes the characters as UTF-16:
     struct Utf16CharBuffer
     {
-        Utf16CharBuffer()
-        {
-            // Can't rely on default initialization of the member array, it
-            // doesn't work at all in very old compilers and works, but warns
-            // about working correctly (!) in even recent versions of MSVC
-            // (warning C4351), so do it manually.
-            data[0] = 0;
-        }
+        // Notice that data is left uninitialized, it is filled by EncodeChar()
+        // which is the only function creating objects of this class.
 
         wchar_t data[3];
         operator const wchar_t*() const { return data; }
@@ -69,12 +63,6 @@ struct WXDLLIMPEXP_BASE wxStringOperationsWchar
     // representation
     struct SingleCharBuffer
     {
-        SingleCharBuffer()
-        {
-            // See comment above.
-            data[0] = 0;
-        }
-
         wxChar data[2];
         operator const wxChar*() const { return data; }
     };
@@ -82,6 +70,7 @@ struct WXDLLIMPEXP_BASE wxStringOperationsWchar
     {
         SingleCharBuffer buf;
         buf.data[0] = (wxChar)ch;
+        buf.data[1] = 0;
         return buf;
     }
     static wxWxCharBuffer EncodeNChars(size_t n, const wxUniChar& ch);
diff --git a/src/common/stringops.cpp b/src/common/stringops.cpp
index 2d8fcaee3e..85629406a3 100644
--- a/src/common/stringops.cpp
+++ b/src/common/stringops.cpp
@@ -38,11 +38,13 @@ wxStringOperationsWchar::Utf16CharBuffer wxStringOperationsWchar::EncodeChar(con
     {
         buf.data[0] = (wchar_t)ch.HighSurrogate();
         buf.data[1] = (wchar_t)ch.LowSurrogate();
+        buf.data[2] = L'\0';
     }
     else
     {
         // Assume ch is a BMP character
         buf.data[0] = (wchar_t)ch;
+        buf.data[1] = L'\0';
     }
     return buf;
 }