From 7872c0d391f45fdc4e92a863137d83f66a6edac3 Mon Sep 17 00:00:00 2001
From: Timo Kreuzer <timo.kreuzer@reactos.org>
Date: Mon, 4 Aug 2025 23:37:09 +0300
Subject: [PATCH] [LIBCNTPR] Implement NT versions of _stricmp and _strnicmp

---
 sdk/lib/crt/string/_stricmp_nt.c  | 43 +++++++++++++++++++++++++++++
 sdk/lib/crt/string/_strnicmp_nt.c | 45 +++++++++++++++++++++++++++++++
 sdk/lib/crt/string/string.cmake   |  6 +++--
 3 files changed, 92 insertions(+), 2 deletions(-)
 create mode 100644 sdk/lib/crt/string/_stricmp_nt.c
 create mode 100644 sdk/lib/crt/string/_strnicmp_nt.c

diff --git a/sdk/lib/crt/string/_stricmp_nt.c b/sdk/lib/crt/string/_stricmp_nt.c
new file mode 100644
index 00000000000..2bec446c3a0
--- /dev/null
+++ b/sdk/lib/crt/string/_stricmp_nt.c
@@ -0,0 +1,43 @@
+/*
+ * PROJECT:     ReactOS NT CRT library
+ * LICENSE:     MIT (https://spdx.org/licenses/MIT)
+ * PURPOSE:     Implementation of _stricmp
+ * COPYRIGHT:   Copyright 2025 Timo Kreuzer <timo.kreuzer@reactos.org>
+ */
+
+#include <string.h>
+
+_Check_return_
+int
+__cdecl
+_stricmp(
+    _In_z_ char const* _String1,
+    _In_z_ char const* _String2)
+{
+    char const* p1 = _String1;
+    char const* p2 = _String2;
+    char chr1, chr2;
+
+    while (1)
+    {
+        chr1 = *p1++;
+        chr2 = *p2++;
+
+        if (chr1 != chr2)
+        {
+            if ((chr1 >= 'A') && (chr1 <= 'Z'))
+                chr1 += ('a' - 'A');
+            if ((chr2 >= 'A') && (chr2 <= 'Z'))
+                chr2 += ('a' - 'A');
+
+            if (chr1 != chr2)
+                return chr1 - chr2;
+        }
+        else if (chr1 == 0)
+        {
+            break;
+        }
+    }
+
+    return 0;
+}
diff --git a/sdk/lib/crt/string/_strnicmp_nt.c b/sdk/lib/crt/string/_strnicmp_nt.c
new file mode 100644
index 00000000000..890944b20be
--- /dev/null
+++ b/sdk/lib/crt/string/_strnicmp_nt.c
@@ -0,0 +1,45 @@
+/*
+ * PROJECT:     ReactOS NT CRT library
+ * LICENSE:     MIT (https://spdx.org/licenses/MIT)
+ * PURPOSE:     Implementation of _strnicmp
+ * COPYRIGHT:   Copyright 2025 Timo Kreuzer <timo.kreuzer@reactos.org>
+ */
+
+#include <string.h>
+
+_Check_return_
+int
+__cdecl
+_strnicmp(
+    _In_reads_or_z_(_MaxCount) char const* _String1,
+    _In_reads_or_z_(_MaxCount) char const* _String2,
+    _In_ size_t _MaxCount)
+{
+    char const* p1 = _String1;
+    char const* p2 = _String2;
+    size_t remaining = _MaxCount;
+    char chr1, chr2;
+
+    while (remaining-- != 0)
+    {
+        chr1 = *p1++;
+        chr2 = *p2++;
+
+        if (chr1 != chr2)
+        {
+            if ((chr1 >= 'A') && (chr1 <= 'Z'))
+                chr1 += ('a' - 'A');
+            if ((chr2 >= 'A') && (chr2 <= 'Z'))
+                chr2 += ('a' - 'A');
+
+            if (chr1 != chr2)
+                return chr1 - chr2;
+        }
+        else if (chr1 == 0)
+        {
+            break;
+        }
+    }
+
+    return 0;
+}
diff --git a/sdk/lib/crt/string/string.cmake b/sdk/lib/crt/string/string.cmake
index 105231205a5..e239ea1f8e5 100644
--- a/sdk/lib/crt/string/string.cmake
+++ b/sdk/lib/crt/string/string.cmake
@@ -6,8 +6,6 @@ list(APPEND LIBCNTPR_STRING_SOURCE
     string/is_wctype.c
     string/scanf.c
     string/strcspn.c
-    string/stricmp.c
-    string/strnicmp.c
     string/strlwr.c
     string/strrev.c
     string/strset.c
@@ -95,8 +93,10 @@ list(APPEND CRT_STRING_SOURCE
     string/strcoll.c
     string/strdup.c
     string/strerror.c
+    string/stricmp.c
     string/string.c
     string/strncoll.c
+    string/strnicmp.c
     string/strtod.c
     string/strtok.c
     string/strtok_s.c
@@ -111,6 +111,8 @@ list(APPEND CRT_STRING_ASM_SOURCE
 )
 
 list(APPEND LIBCNTPR_STRING_SOURCE
+    string/_stricmp_nt.c
+    string/_strnicmp_nt.c
     string/iswctype_nt.c
     string/mbstowcs_nt.c
     string/tolower_nt.c