From 34eab77bed46dc212f8f084b8aeee77729c59c2d Mon Sep 17 00:00:00 2001
From: Rainer Kottenhoff <rainer.kottenhoff@gmail.com>
Date: Tue, 11 May 2021 19:25:40 +0200
Subject: [PATCH] + fix: TinyExpr: UTF-8 to ANSI-CP-1252 conversion should
 yield invalid characters instead of blank or currency

---
 src/Notepad3.c          | 9 ++++++---
 src/tinyexpr/tinyexpr.h | 3 +++
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/Notepad3.c b/src/Notepad3.c
index 8ac268932..4b5303f76 100644
--- a/src/Notepad3.c
+++ b/src/Notepad3.c
@@ -209,7 +209,7 @@ static const int NUMTOOLBITMAPS = 30;
 
 // ----------------------------------------------------------------------------
 
-const char chr_currency[6] = { '$', 0x80, 0xA2, 0xA3, 0xA5, '\0' }; // "$€¢£¥"
+const char chr_currency[6] = { '$', 0x80, 0xA2, 0xA3, 0xA5, '\0' }; // "$€¢£¥" CP-1252
 
 // ----------------------------------------------------------------------------
 
@@ -2086,10 +2086,13 @@ static bool _EvalTinyExpr(bool qmark)
             DocPos const iLnCaretPos = SciCall_GetCurLine((lineLen - 1), lineBuf);
             lineBuf[iLnCaretPos - (posSelStart - posBefore)] = '\0'; // exclude "=?"
 
-            char const defchar = (char)0x24;
+            char const defchar = (char)te_invalid_chr();
             MultiByteToWideChar(Encoding_SciCP, 0, lineBuf, -1, lineBufW, lineLen);
-            WideCharToMultiByte(te_cp(), (WC_COMPOSITECHECK | WC_DISCARDNS), lineBufW, -1, lineBuf, lineLen, &defchar, NULL);
+            int const len = WideCharToMultiByte(te_cp(), (WC_COMPOSITECHECK | WC_DISCARDNS), lineBufW, -1, lineBuf, lineLen, &defchar, NULL);
             FreeMem(lineBufW);
+            if (!len) {
+                return false;
+            }
 
             // canonicalize fetched line
             StrDelChrA(lineBuf, chr_currency);
diff --git a/src/tinyexpr/tinyexpr.h b/src/tinyexpr/tinyexpr.h
index 63649dad6..1e24dc624 100644
--- a/src/tinyexpr/tinyexpr.h
+++ b/src/tinyexpr/tinyexpr.h
@@ -108,6 +108,9 @@ void te_free(te_expr *n);
 /* ANSI codepage of te operators */
 inline unsigned te_cp() { return 1252U; }
 
+/* invalid default char for conversion */
+inline unsigned te_invalid_chr() { return '#'; }
+
 /* check for operator or special character. */
 inline int te_is_op(const char* const expr) {
     if (!expr)