From 8c7b566629e3f8706580a73cc8da152879c9f9ef Mon Sep 17 00:00:00 2001
From: Tim Schumacher <timschumi@gmx.de>
Date: Fri, 17 Sep 2021 18:28:28 +0200
Subject: [PATCH] LibC: Implement iswctype

---
 Tests/LibC/TestWctype.cpp          | 27 ++++++++++++++++++
 Userland/Libraries/LibC/wctype.cpp | 44 ++++++++++++++++++++++++++++--
 2 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/Tests/LibC/TestWctype.cpp b/Tests/LibC/TestWctype.cpp
index 401ce66635682f..ed1d7d0028575d 100644
--- a/Tests/LibC/TestWctype.cpp
+++ b/Tests/LibC/TestWctype.cpp
@@ -39,3 +39,30 @@ TEST_CASE(wctrans)
     EXPECT(wctrans("") == 0);
     EXPECT(wctrans("abc") == 0);
 }
+
+TEST_CASE(iswctype)
+{
+    const wint_t test_chars[] = { L'A', L'a', L'F', L'f', L'Z', L'z', L'0', L'\n', L'.', L'\x00' };
+
+    // Test that valid properties are wired to the correct implementation.
+    for (unsigned int i = 0; i < sizeof(test_chars) / sizeof(test_chars[0]); i++) {
+        EXPECT(iswctype(test_chars[i], wctype("alnum")) == iswalnum(test_chars[i]));
+        EXPECT(iswctype(test_chars[i], wctype("alpha")) == iswalpha(test_chars[i]));
+        EXPECT(iswctype(test_chars[i], wctype("blank")) == iswblank(test_chars[i]));
+        EXPECT(iswctype(test_chars[i], wctype("cntrl")) == iswcntrl(test_chars[i]));
+        EXPECT(iswctype(test_chars[i], wctype("digit")) == iswdigit(test_chars[i]));
+        EXPECT(iswctype(test_chars[i], wctype("graph")) == iswgraph(test_chars[i]));
+        EXPECT(iswctype(test_chars[i], wctype("lower")) == iswlower(test_chars[i]));
+        EXPECT(iswctype(test_chars[i], wctype("print")) == iswprint(test_chars[i]));
+        EXPECT(iswctype(test_chars[i], wctype("punct")) == iswpunct(test_chars[i]));
+        EXPECT(iswctype(test_chars[i], wctype("space")) == iswspace(test_chars[i]));
+        EXPECT(iswctype(test_chars[i], wctype("upper")) == iswupper(test_chars[i]));
+        EXPECT(iswctype(test_chars[i], wctype("xdigit")) == iswxdigit(test_chars[i]));
+    }
+
+    // Test that invalid properties always return zero.
+    for (unsigned int i = 0; i < sizeof(test_chars) / sizeof(test_chars[0]); i++) {
+        EXPECT(iswctype(test_chars[i], 0) == 0);
+        EXPECT(iswctype(test_chars[i], -1) == 0);
+    }
+}
diff --git a/Userland/Libraries/LibC/wctype.cpp b/Userland/Libraries/LibC/wctype.cpp
index 083e8e75dae2fd..9bb3e4fc03611f 100644
--- a/Userland/Libraries/LibC/wctype.cpp
+++ b/Userland/Libraries/LibC/wctype.cpp
@@ -92,10 +92,48 @@ int iswblank(wint_t wc)
     return __inline_isblank(wc);
 }
 
-int iswctype(wint_t, wctype_t)
+int iswctype(wint_t wc, wctype_t charclass)
 {
-    dbgln("FIXME: Implement iswctype()");
-    TODO();
+    switch (charclass) {
+    case WCTYPE_ALNUM:
+        return iswalnum(wc);
+
+    case WCTYPE_ALPHA:
+        return iswalpha(wc);
+
+    case WCTYPE_BLANK:
+        return iswblank(wc);
+
+    case WCTYPE_CNTRL:
+        return iswcntrl(wc);
+
+    case WCTYPE_DIGIT:
+        return iswdigit(wc);
+
+    case WCTYPE_GRAPH:
+        return iswgraph(wc);
+
+    case WCTYPE_LOWER:
+        return iswlower(wc);
+
+    case WCTYPE_PRINT:
+        return iswprint(wc);
+
+    case WCTYPE_PUNCT:
+        return iswpunct(wc);
+
+    case WCTYPE_SPACE:
+        return iswspace(wc);
+
+    case WCTYPE_UPPER:
+        return iswupper(wc);
+
+    case WCTYPE_XDIGIT:
+        return iswxdigit(wc);
+
+    default:
+        return 0;
+    }
 }
 
 wctype_t wctype(const char* property)