[libc] Implemented wmemmove (#142245)

Implemented wmemmove and added tests

libc/test/src/wchar/CMakeLists.txt

@@ -145,6 +145,16 @@ add_libc_test(
     libc.src.wchar.wmemcpy
 )
 
+add_libc_test(
+  wmemmove_test
+  SUITE
+    libc_wchar_unittests
+  SRCS
+    wmemmove_test.cpp
+  DEPENDS
+    libc.src.wchar.wmemmove
+)
+
 add_libc_test(
   wcsncpy_test
   SUITE

libc/test/src/wchar/wmemmove_test.cpp

@@ -0,0 +1,111 @@
+//===-- Unittests for wmemmove --------------------------------------------===//
+//
+// 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/wmemmove.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcWMemmoveTest, MoveZeroByte) {
+  wchar_t buffer[] = {L'a', L'b', L'y', L'z'};
+
+  wchar_t *ret = LIBC_NAMESPACE::wmemmove(buffer, buffer + 2, 0);
+  EXPECT_EQ(ret, buffer);
+
+  const wchar_t expected[] = {L'a', L'b', L'y', L'z'};
+  EXPECT_TRUE(buffer[0] == expected[0]);
+  EXPECT_TRUE(buffer[1] == expected[1]);
+  EXPECT_TRUE(buffer[2] == expected[2]);
+  EXPECT_TRUE(buffer[3] == expected[3]);
+}
+
+TEST(LlvmLibcWMemmoveTest, DstAndSrcPointToSameAddress) {
+  wchar_t buffer[] = {L'a', L'b'};
+
+  wchar_t *ret = LIBC_NAMESPACE::wmemmove(buffer, buffer, 1);
+  EXPECT_EQ(ret, buffer);
+
+  const wchar_t expected[] = {L'a', L'b'};
+  EXPECT_TRUE(buffer[0] == expected[0]);
+  EXPECT_TRUE(buffer[1] == expected[1]);
+}
+
+TEST(LlvmLibcWMemmoveTest, DstStartsBeforeSrc) {
+  // Set boundary at beginning and end for not overstepping when
+  // copy forward or backward.
+  wchar_t buffer[] = {L'z', L'a', L'b', L'c', L'z'};
+
+  wchar_t *dst = buffer + 1;
+  wchar_t *ret = LIBC_NAMESPACE::wmemmove(dst, buffer + 2, 2);
+  EXPECT_EQ(ret, dst);
+
+  const wchar_t expected[] = {L'z', L'b', L'c', L'c', L'z'};
+  EXPECT_TRUE(buffer[0] == expected[0]);
+  EXPECT_TRUE(buffer[1] == expected[1]);
+  EXPECT_TRUE(buffer[2] == expected[2]);
+  EXPECT_TRUE(buffer[3] == expected[3]);
+  EXPECT_TRUE(buffer[4] == expected[4]);
+}
+
+TEST(LlvmLibcWMemmoveTest, DstStartsAfterSrc) {
+  wchar_t buffer[] = {L'z', L'a', L'b', L'c', L'z'};
+
+  wchar_t *dst = buffer + 2;
+  wchar_t *ret = LIBC_NAMESPACE::wmemmove(dst, buffer + 1, 2);
+  EXPECT_EQ(ret, dst);
+
+  const wchar_t expected[] = {L'z', L'a', L'a', L'b', L'z'};
+  EXPECT_TRUE(buffer[0] == expected[0]);
+  EXPECT_TRUE(buffer[1] == expected[1]);
+  EXPECT_TRUE(buffer[2] == expected[2]);
+  EXPECT_TRUE(buffer[3] == expected[3]);
+  EXPECT_TRUE(buffer[4] == expected[4]);
+}
+
+// e.g. `Dst` follow `src`.
+// str: [abcdefghij]
+//      [__src_____]
+//      [_____Dst__]
+TEST(LlvmLibcWMemmoveTest, SrcFollowDst) {
+  wchar_t buffer[] = {L'z', L'a', L'b', L'z'};
+
+  wchar_t *dst = buffer + 1;
+  wchar_t *ret = LIBC_NAMESPACE::wmemmove(dst, buffer + 2, 1);
+  EXPECT_EQ(ret, dst);
+
+  const char expected[] = {L'z', L'b', L'b', L'z'};
+  EXPECT_TRUE(buffer[0] == expected[0]);
+  EXPECT_TRUE(buffer[1] == expected[1]);
+  EXPECT_TRUE(buffer[2] == expected[2]);
+  EXPECT_TRUE(buffer[3] == expected[3]);
+}
+
+TEST(LlvmLibcWMemmoveTest, DstFollowSrc) {
+  wchar_t buffer[] = {L'z', L'a', L'b', L'z'};
+
+  wchar_t *dst = buffer + 2;
+  wchar_t *ret = LIBC_NAMESPACE::wmemmove(dst, buffer + 1, 1);
+  EXPECT_EQ(ret, dst);
+
+  const char expected[] = {L'z', L'a', L'a', L'z'};
+  EXPECT_TRUE(buffer[0] == expected[0]);
+  EXPECT_TRUE(buffer[1] == expected[1]);
+  EXPECT_TRUE(buffer[2] == expected[2]);
+  EXPECT_TRUE(buffer[3] == expected[3]);
+}
+
+#if defined(LIBC_ADD_NULL_CHECKS) && !defined(LIBC_HAS_SANITIZER)
+TEST(LlvmLibcWMemmoveTest, NullptrCrash) {
+  wchar_t buffer[] = {L'a', L'b'};
+  // Passing in a nullptr should crash the program.
+  EXPECT_DEATH([&buffer] { LIBC_NAMESPACE::wmemmove(buffer, nullptr, 2); },
+               WITH_SIGNAL(-1));
+  EXPECT_DEATH([&buffer] { LIBC_NAMESPACE::wmemmove(nullptr, buffer, 2); },
+               WITH_SIGNAL(-1));
+}
+#endif // LIBC_HAS_ADDRESS_SANITIZER