From ff0ab8b9a96ab784d9cd077b5f8e105492e55b9b Mon Sep 17 00:00:00 2001
From: Tim Schumacher <timschumi@gmx.de>
Date: Fri, 17 Sep 2021 18:19:09 +0200
Subject: [PATCH] LibC: Implement wctrans

---
 Tests/LibC/TestWctype.cpp          | 11 +++++++++++
 Userland/Libraries/LibC/wctype.cpp | 17 ++++++++++++++---
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/Tests/LibC/TestWctype.cpp b/Tests/LibC/TestWctype.cpp
index 190d152f6d..401ce66635 100644
--- a/Tests/LibC/TestWctype.cpp
+++ b/Tests/LibC/TestWctype.cpp
@@ -28,3 +28,14 @@ TEST_CASE(wctype)
     EXPECT(wctype("") == 0);
     EXPECT(wctype("abc") == 0);
 }
+
+TEST_CASE(wctrans)
+{
+    // Test that existing character mappings return non-zero wctrans values.
+    EXPECT(wctrans("tolower") != 0);
+    EXPECT(wctrans("toupper") != 0);
+
+    // Test that invalid character mappings return the "invalid" wctrans value (0).
+    EXPECT(wctrans("") == 0);
+    EXPECT(wctrans("abc") == 0);
+}
diff --git a/Userland/Libraries/LibC/wctype.cpp b/Userland/Libraries/LibC/wctype.cpp
index 10830c0c00..083e8e75da 100644
--- a/Userland/Libraries/LibC/wctype.cpp
+++ b/Userland/Libraries/LibC/wctype.cpp
@@ -24,6 +24,12 @@ enum {
     WCTYPE_XDIGIT,
 };
 
+enum {
+    WCTRANS_INVALID = 0,
+    WCTRANS_TOLOWER,
+    WCTRANS_TOUPPER,
+};
+
 extern "C" {
 
 int iswalnum(wint_t wc)
@@ -149,9 +155,14 @@ wint_t towctrans(wint_t, wctrans_t)
     TODO();
 }
 
-wctrans_t wctrans(const char*)
+wctrans_t wctrans(const char* charclass)
 {
-    dbgln("FIXME: Implement wctrans()");
-    TODO();
+    if (strcmp(charclass, "tolower") == 0)
+        return WCTRANS_TOLOWER;
+
+    if (strcmp(charclass, "toupper") == 0)
+        return WCTRANS_TOUPPER;
+
+    return WCTRANS_INVALID;
 }
 }