[libc-commits] [libc] [libc] wmemcmp implementation (PR #141880)

[Michael Jones via libc-commits]

================
@@ -0,0 +1,68 @@
+//===-- Unittests for wmemcmp ---------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "hdr/types/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/wchar/wmemcmp.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcWMemcmpTest, CmpZeroByte) {
+  // Comparing zero bytes should result in 0.
+  const wchar_t *lhs = L"ab";
+  const wchar_t *rhs = L"yz";
+  EXPECT_EQ(LIBC_NAMESPACE::wmemcmp(lhs, rhs, 0), 0);
+}
+
+TEST(LlvmLibcWMemcmpTest, LhsRhsAreTheSame) {
+  // Comparing strings of equal value should result in 0.
+  const wchar_t *lhs = L"ab";
+  const wchar_t *rhs = L"ab";
+  EXPECT_EQ(LIBC_NAMESPACE::wmemcmp(lhs, rhs, 2), 0);
+}
+
+TEST(LlvmLibcWMemcmpTest, LhsBeforeRhsLexically) {
+  // z after b, should result in a value less than 0.
+  const wchar_t *lhs = L"ab";
+  const wchar_t *rhs = L"az";
+  EXPECT_LT(LIBC_NAMESPACE::wmemcmp(lhs, rhs, 2), 0);
+}
+
+TEST(LlvmLibcWMemcmpTest, LhsAfterRhsLexically) {
+  // z after b, should result in a value greater than 0.
+  const wchar_t *lhs = L"az";
+  const wchar_t *rhs = L"ab";
+  EXPECT_GT(LIBC_NAMESPACE::wmemcmp(lhs, rhs, 2), 0);
+}
+
+TEST(LlvmLibcWMemcmpTest, CompareToEmpty) {
+  // lhs is nonempty, should result in a value greater than 0.
+  const wchar_t *lhs = L"az";
+  const wchar_t *rhs = L"";
+  EXPECT_GT(LIBC_NAMESPACE::wmemcmp(lhs, rhs, 2), 0);
----------------
michaelrj-google wrote:

this should probably only compare 1 character, since `rhs` should only be the null terminator.

https://github.com/llvm/llvm-project/pull/141880