[reactos] 06/11: [RTL] Fix RtlIsValidOemCharacter implementation for Multibyte code pages

[Jérôme Gardou]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=49fcbe7cd8531178970ff…

commit 49fcbe7cd8531178970ffe48f91f3dc4d68022d1
Author:     Jérôme Gardou <jerome.gardou(a)reactos.org>
AuthorDate: Mon May 17 16:14:26 2021 +0200
Commit:     Jérôme Gardou <zefklop(a)users.noreply.github.com>
CommitDate: Wed May 19 22:50:29 2021 +0200

    [RTL] Fix RtlIsValidOemCharacter implementation for Multibyte code pages
    
    CORE-17571
---
 sdk/lib/rtl/unicode.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/sdk/lib/rtl/unicode.c b/sdk/lib/rtl/unicode.c
index 7f045401326..e1896497ce6 100644
--- a/sdk/lib/rtl/unicode.c
+++ b/sdk/lib/rtl/unicode.c
@@ -519,16 +519,24 @@ RtlIsValidOemCharacter(IN PWCHAR Char)
     /* If multi-byte code page present */
     if (NlsMbOemCodePageTag)
     {
-        USHORT Offset = 0;
+        USHORT Offset;
 
         OemChar = NlsUnicodeToMbOemTable[*Char];
 
         /* If character has Lead Byte */
-        if (NlsOemLeadByteInfo[HIBYTE(OemChar)])
-            Offset = NlsOemLeadByteInfo[HIBYTE(OemChar)];
+        Offset = NlsOemLeadByteInfo[HIBYTE(OemChar)];
+        if (Offset)
+        {
+            /* Use DBCS table */
+            UnicodeChar = NlsOemLeadByteInfo[Offset + LOBYTE(OemChar)];
+        }
+        else
+        {
+            UnicodeChar = NlsOemToUnicodeTable[OemChar];
+        }
 
-        /* Receive Unicode character from the table */
-        UnicodeChar = RtlpUpcaseUnicodeChar(NlsOemToUnicodeTable[LOBYTE(OemChar) +
Offset]);
+        /* Upcase */
+        UnicodeChar = RtlpUpcaseUnicodeChar(UnicodeChar);
 
         /* Receive OEM character from the table */
         OemChar = NlsUnicodeToMbOemTable[UnicodeChar];
@@ -544,7 +552,10 @@ RtlIsValidOemCharacter(IN PWCHAR Char)
 
     /* Not valid character, failed */
     if (OemChar == NlsOemDefaultChar)
+    {
+        DPRINT1("\\u%04x is not valid for OEM\n", *Char);
         return FALSE;
+    }
 
     *Char = UnicodeChar;