1 files changed, 99 insertions, 0 deletions
diff --git a/libc/test/src/strings/bcopy_test.cpp b/libc/test/src/strings/bcopy_test.cpp
new file mode 100644
index 000000000000..f6bb859b4ae9
--- /dev/null
+++ b/libc/test/src/strings/bcopy_test.cpp
@@ -0,0 +1,99 @@
+//===-- Unittests for bcopy -----------------------------------------------===//
+//
+// 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 "src/strings/bcopy.h"
+
+#include "src/__support/CPP/span.h"
+#include "src/__support/macros/config.h"
+#include "test/UnitTest/MemoryMatcher.h"
+#include "test/UnitTest/Test.h"
+#include "test/src/string/memory_utils/memory_check_utils.h"
+
+using LIBC_NAMESPACE::cpp::array;
+using LIBC_NAMESPACE::cpp::span;
+
+namespace LIBC_NAMESPACE_DECL {
+
+TEST(LlvmLibcBcopyTest, MoveZeroByte) {
+  char Buffer[] = {'a', 'b', 'y', 'z'};
+  const char Expected[] = {'a', 'b', 'y', 'z'};
+  void *const Dst = Buffer;
+  LIBC_NAMESPACE::bcopy(Buffer + 2, Dst, 0);
+  ASSERT_MEM_EQ(Buffer, testing::MemoryView(Expected));
+}
+
+TEST(LlvmLibcBcopyTest, DstAndSrcPointToSameAddress) {
+  char Buffer[] = {'a', 'b'};
+  const char Expected[] = {'a', 'b'};
+  void *const Dst = Buffer;
+  LIBC_NAMESPACE::bcopy(Buffer, Dst, 1);
+  ASSERT_MEM_EQ(Buffer, testing::MemoryView(Expected));
+}
+
+TEST(LlvmLibcBcopyTest, DstStartsBeforeSrc) {
+  // Set boundary at beginning and end for not overstepping when
+  // copy forward or backward.
+  char Buffer[] = {'z', 'a', 'b', 'c', 'z'};
+  const char Expected[] = {'z', 'b', 'c', 'c', 'z'};
+  void *const Dst = Buffer + 1;
+  LIBC_NAMESPACE::bcopy(Buffer + 2, Dst, 2);
+  ASSERT_MEM_EQ(Buffer, testing::MemoryView(Expected));
+}
+
+TEST(LlvmLibcBcopyTest, DstStartsAfterSrc) {
+  char Buffer[] = {'z', 'a', 'b', 'c', 'z'};
+  const char Expected[] = {'z', 'a', 'a', 'b', 'z'};
+  void *const Dst = Buffer + 2;
+  LIBC_NAMESPACE::bcopy(Buffer + 1, Dst, 2);
+  ASSERT_MEM_EQ(Buffer, testing::MemoryView(Expected));
+}
+
+// e.g. `Dst` follow `src`.
+// str: [abcdefghij]
+//      [__src_____]
+//      [_____Dst__]
+TEST(LlvmLibcBcopyTest, SrcFollowDst) {
+  char Buffer[] = {'z', 'a', 'b', 'z'};
+  const char Expected[] = {'z', 'b', 'b', 'z'};
+  void *const Dst = Buffer + 1;
+  LIBC_NAMESPACE::bcopy(Buffer + 2, Dst, 1);
+  ASSERT_MEM_EQ(Buffer, testing::MemoryView(Expected));
+}
+
+TEST(LlvmLibcBcopyTest, DstFollowSrc) {
+  char Buffer[] = {'z', 'a', 'b', 'z'};
+  const char Expected[] = {'z', 'a', 'a', 'z'};
+  void *const Dst = Buffer + 2;
+  LIBC_NAMESPACE::bcopy(Buffer + 1, Dst, 1);
+  ASSERT_MEM_EQ(Buffer, testing::MemoryView(Expected));
+}
+
+// Adapt CheckMemmove signature to bcopy.
+static inline void Adaptor(cpp::span<char> dst, cpp::span<char> src,
+                           size_t size) {
+  LIBC_NAMESPACE::bcopy(src.begin(), dst.begin(), size);
+}
+
+TEST(LlvmLibcBcopyTest, SizeSweep) {
+  static constexpr int kMaxSize = 400;
+  static constexpr int kDenseOverlap = 15;
+  using LargeBuffer = array<char, 2 * kMaxSize + 1>;
+  LargeBuffer Buffer;
+  Randomize(Buffer);
+  for (int Size = 0; Size < kMaxSize; ++Size)
+    for (int Overlap = -1; Overlap < Size;) {
+      ASSERT_TRUE(CheckMemmove<Adaptor>(Buffer, Size, Overlap));
+      // Prevent quadratic behavior by skipping offset above kDenseOverlap.
+      if (Overlap > kDenseOverlap)
+        Overlap *= 2;
+      else
+        ++Overlap;
+    }
+}
+
+} // namespace LIBC_NAMESPACE_DECL