From f20c09fcd692515d12f211d2adce1792ca9d8556 Mon Sep 17 00:00:00 2001
From: Timo Kreuzer <timo.kreuzer@reactos.org>
Date: Mon, 4 Aug 2025 20:33:58 +0300
Subject: [PATCH] [LIBCNTPR] Implement NT versions of _strlwr, _strupr,
 _wcslwr, _wcsupr

---
 sdk/lib/crt/string/_strlwr_nt.c   | 27 +++++++++++++++++++++++++
 sdk/lib/crt/string/_strupr_nt.c   | 33 +++++++++++++++++++++++++++++++
 sdk/lib/crt/string/string.cmake   |  6 ++++--
 sdk/lib/crt/wstring/_wcslwr_nt.c  | 33 +++++++++++++++++++++++++++++++
 sdk/lib/crt/wstring/_wcsupr_nt.c  | 27 +++++++++++++++++++++++++
 sdk/lib/crt/wstring/wstring.cmake |  6 ++++--
 6 files changed, 128 insertions(+), 4 deletions(-)
 create mode 100644 sdk/lib/crt/string/_strlwr_nt.c
 create mode 100644 sdk/lib/crt/string/_strupr_nt.c
 create mode 100644 sdk/lib/crt/wstring/_wcslwr_nt.c
 create mode 100644 sdk/lib/crt/wstring/_wcsupr_nt.c

diff --git a/sdk/lib/crt/string/_strlwr_nt.c b/sdk/lib/crt/string/_strlwr_nt.c
new file mode 100644
index 00000000000..b83f1b13609
--- /dev/null
+++ b/sdk/lib/crt/string/_strlwr_nt.c
@@ -0,0 +1,27 @@
+/*
+ * PROJECT:     ReactOS NT CRT library
+ * LICENSE:     MIT (https://spdx.org/licenses/MIT)
+ * PURPOSE:     Implementation of _strlwr
+ * COPYRIGHT:   Copyright 2025 Timo Kreuzer <timo.kreuzer@reactos.org>
+ */
+
+#include <string.h>
+
+char*
+__cdecl
+_strlwr(
+    _Inout_z_ char* _String)
+{
+    char ch, *p;
+
+    for (p = _String; *p; p++)
+    {
+        ch = *p;
+        if ((ch >= 'A') && (ch <= 'Z'))
+        {
+            *p += 'a' - 'A';
+        }
+    }
+
+    return _String;
+}
diff --git a/sdk/lib/crt/string/_strupr_nt.c b/sdk/lib/crt/string/_strupr_nt.c
new file mode 100644
index 00000000000..dc488a8799c
--- /dev/null
+++ b/sdk/lib/crt/string/_strupr_nt.c
@@ -0,0 +1,33 @@
+/*
+ * PROJECT:     ReactOS NT CRT library
+ * LICENSE:     MIT (https://spdx.org/licenses/MIT)
+ * PURPOSE:     Implementation of _strupr
+ * COPYRIGHT:   Copyright 2025 Timo Kreuzer <timo.kreuzer@reactos.org>
+ */
+
+#include "precomp.h"
+
+char*
+__cdecl
+_strupr(
+    _Inout_z_ char* _String)
+{
+    char ch, *p;
+
+    if (_String == NULL)
+    {
+        _invalid_parameter(NULL, L"_strupr", _CRT_WIDE(__FILE__), __LINE__, 0);
+        return NULL;
+    }
+
+    for (p = _String; *p; p++)
+    {
+        ch = *p;
+        if ((ch >= 'a') && (ch <= 'z'))
+        {
+            *p += 'A' - 'a';
+        }
+    }
+
+    return _String;
+}
diff --git a/sdk/lib/crt/string/string.cmake b/sdk/lib/crt/string/string.cmake
index e239ea1f8e5..797683e1c0e 100644
--- a/sdk/lib/crt/string/string.cmake
+++ b/sdk/lib/crt/string/string.cmake
@@ -6,11 +6,9 @@ list(APPEND LIBCNTPR_STRING_SOURCE
     string/is_wctype.c
     string/scanf.c
     string/strcspn.c
-    string/strlwr.c
     string/strrev.c
     string/strset.c
     string/strstr.c
-    string/strupr.c
     string/strpbrk.c
     string/strspn.c
     string/atoi64.c
@@ -95,12 +93,14 @@ list(APPEND CRT_STRING_SOURCE
     string/strerror.c
     string/stricmp.c
     string/string.c
+    string/strlwr.c
     string/strncoll.c
     string/strnicmp.c
     string/strtod.c
     string/strtok.c
     string/strtok_s.c
     string/strtoul.c
+    string/strupr.c
     string/strxfrm.c
     string/wcstombs_s.c
     string/wtof.c
@@ -112,7 +112,9 @@ list(APPEND CRT_STRING_ASM_SOURCE
 
 list(APPEND LIBCNTPR_STRING_SOURCE
     string/_stricmp_nt.c
+    string/_strlwr_nt.c
     string/_strnicmp_nt.c
+    string/_strupr_nt.c
     string/iswctype_nt.c
     string/mbstowcs_nt.c
     string/tolower_nt.c
diff --git a/sdk/lib/crt/wstring/_wcslwr_nt.c b/sdk/lib/crt/wstring/_wcslwr_nt.c
new file mode 100644
index 00000000000..24f05746068
--- /dev/null
+++ b/sdk/lib/crt/wstring/_wcslwr_nt.c
@@ -0,0 +1,33 @@
+/*
+ * PROJECT:     ReactOS NT CRT library
+ * LICENSE:     MIT (https://spdx.org/licenses/MIT)
+ * PURPOSE:     Implementation of _wcslwr
+ * COPYRIGHT:   Copyright 2025 Timo Kreuzer <timo.kreuzer@reactos.org>
+ */
+
+#include "precomp.h"
+
+wchar_t*
+__cdecl
+_wcslwr(
+    _Inout_z_ wchar_t* _String)
+{
+    wchar_t ch, *p;
+
+    if (_String == NULL)
+    {
+        _invalid_parameter(NULL, L"_wcslwr", _CRT_WIDE(__FILE__), __LINE__, 0);
+        return NULL;
+    }
+
+    for (p = _String; *p; p++)
+    {
+        ch = *p;
+        if ((ch >= 'A') && (ch <= 'Z'))
+        {
+            *p += 'a' - 'A';
+        }
+    }
+
+    return _String;
+}
diff --git a/sdk/lib/crt/wstring/_wcsupr_nt.c b/sdk/lib/crt/wstring/_wcsupr_nt.c
new file mode 100644
index 00000000000..cd3717a841d
--- /dev/null
+++ b/sdk/lib/crt/wstring/_wcsupr_nt.c
@@ -0,0 +1,27 @@
+/*
+ * PROJECT:     ReactOS NT CRT library
+ * LICENSE:     MIT (https://spdx.org/licenses/MIT)
+ * PURPOSE:     Implementation of _wcsupr
+ * COPYRIGHT:   Copyright 2025 Timo Kreuzer <timo.kreuzer@reactos.org>
+ */
+
+#include <string.h>
+
+wchar_t*
+__cdecl
+_wcsupr(
+    _Inout_z_ wchar_t* _String)
+{
+    wchar_t ch, *p;
+
+    for (p = _String; *p; p++)
+    {
+        ch = *p;
+        if ((ch >= 'a') && (ch <= 'z'))
+        {
+            *p += 'A' - 'a';
+        }
+    }
+
+    return _String;
+}
diff --git a/sdk/lib/crt/wstring/wstring.cmake b/sdk/lib/crt/wstring/wstring.cmake
index df6b0fac4dd..4af11bb6e86 100644
--- a/sdk/lib/crt/wstring/wstring.cmake
+++ b/sdk/lib/crt/wstring/wstring.cmake
@@ -1,7 +1,5 @@
 
 list(APPEND LIBCNTPR_WSTRING_SOURCE
-    wstring/wcslwr.c
-    wstring/wcsupr.c
     wstring/wcscspn.c
     wstring/wcsspn.c
     wstring/wcsstr.c
@@ -13,12 +11,16 @@ list(APPEND CRT_WSTRING_SOURCE
     wstring/wcrtomb.c
     wstring/wcscoll.c
     wstring/wcsicmp.c
+    wstring/wcslwr.c
     wstring/wcsnicmp.c
     wstring/wcstok.c
+    wstring/wcsupr.c
     wstring/wcsxfrm.c
 )
 
 list(APPEND LIBCNTPR_WSTRING_SOURCE
     wstring/_wcsicmp_nt.c
+    wstring/_wcslwr_nt.c
     wstring/_wcsnicmp_nt.c
+    wstring/_wcsupr_nt.c
 )