[libc] [llvm] [libc] wcslcat implementation (PR #146588)

[Michael Jones via llvm-commits]

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+//===-- Unittests for wcslcat ---------------------------------------------===//
+//
+// 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/wcslcat.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcWCSLCatTest, TooBig) {
+  const wchar_t *src = L"cd";
+  wchar_t dst[4]{L"ab"};
+  size_t res = LIBC_NAMESPACE::wcslcat(dst, src, 3);
+  ASSERT_TRUE(dst[0] == L'a');
+  ASSERT_TRUE(dst[1] == L'b');
+  ASSERT_TRUE(dst[2] == L'\0');
+  // Should still return src length + dst length
+  ASSERT_EQ(res, size_t(4));
+  // Not enough space to copy d
+  res = LIBC_NAMESPACE::wcslcat(dst, src, 4);
+  ASSERT_TRUE(dst[0] == L'a');
+  ASSERT_TRUE(dst[1] == L'b');
+  ASSERT_TRUE(dst[2] == L'c');
+  ASSERT_TRUE(dst[3] == L'\0');
+  ASSERT_EQ(res, size_t(4));
+}
+
+TEST(LlvmLibcWCSLCatTest, Smaller) {
+  const wchar_t *src = L"cd";
+  wchar_t dst[7]{L"ab"};
+  size_t res = LIBC_NAMESPACE::wcslcat(dst, src, 7);
+  ASSERT_TRUE(dst[0] == L'a');
+  ASSERT_TRUE(dst[1] == L'b');
+  ASSERT_TRUE(dst[2] == L'c');
+  ASSERT_TRUE(dst[3] == L'd');
+  ASSERT_TRUE(dst[4] == L'\0');
+  ASSERT_EQ(res, size_t(4));
+}
+
+TEST(LlvmLibcWCSLCatTest, SmallerNoOverwriteAfter0) {
+  const wchar_t *src = L"cd";
+  wchar_t dst[8]{L"ab\0\0efg"};
+  size_t res = LIBC_NAMESPACE::wcslcat(dst, src, 8);
+  ASSERT_TRUE(dst[0] == L'a');
+  ASSERT_TRUE(dst[1] == L'b');
+  ASSERT_TRUE(dst[2] == L'c');
+  ASSERT_TRUE(dst[3] == L'd');
+  ASSERT_TRUE(dst[4] == L'\0');
+  ASSERT_TRUE(dst[5] == L'f');
+  ASSERT_TRUE(dst[6] == L'g');
+  ASSERT_TRUE(dst[7] == L'\0');
+  ASSERT_EQ(res, size_t(4));
+}
+
+TEST(LlvmLibcWCSLCatTest, No0) {
+  const wchar_t *src = L"cd";
+  wchar_t dst[7]{L"ab"};
+  size_t res = LIBC_NAMESPACE::wcslcat(dst, src, 1);
+  ASSERT_TRUE(dst[0] == L'a');
+  ASSERT_TRUE(dst[1] == L'b');
+  ASSERT_TRUE(dst[2] == L'\0');
+  ASSERT_EQ(res, size_t(3));
+  res = LIBC_NAMESPACE::wcslcat(dst, src, 2);
+  ASSERT_TRUE(dst[0] == L'a');
+  ASSERT_TRUE(dst[1] == L'b');
+  ASSERT_TRUE(dst[2] == L'\0');
+  ASSERT_EQ(res, size_t(4));
+}
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michaelrj-google wrote:

I don't see how this test is different from `TooBig`

https://github.com/llvm/llvm-project/pull/146588