ICUCtypeData: Fix MB_CUR_MAX under most encodings.

See inline comment. Fixes #19881.
2026-01-15 18:48:10 -05:00
parent f1ca09f6a2
commit 7b94842122
1 changed files with 8 additions and 1 deletions
@@ -74,7 +74,14 @@ ICUCtypeData::SetTo(const Locale& locale, const char* posixLocaleName)

 	ucnv_reset(converter);

-	*fDataBridge->addrOfMbCurMax = ucnv_getMaxCharSize(converter);
+	short mbMax = ucnv_getMaxCharSize(converter);
+	if (mbMax > 1 && mbMax < 4) {
+		// ucnv_getMaxCharSize() returns the maximum size of an encoded UChar,
+		// which is 16-bit, and not a 32-bit Unicode codepoint. So, unless
+		// some exotic encoding is being used, 4 is the value we actually want.
+		mbMax = 4;
+	}
+	*fDataBridge->addrOfMbCurMax = mbMax;

 	char buffer[] = { 0, 0 };
 	for (int i = 0; i < 256; ++i) {