Add few docs and implementation of strcpy and strcat.

Summary:
This patch illustrates some of the features like modularity we want
in the new libc. Few other ideas like different kinds of testing, redirectors
etc are not yet present.

Reviewers: dlj, hfinkel, theraven, jfb, alexshap, jdoerfert

Subscribers: mgorny, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67867

llvm-svn: 373764

1 files changed, 40 insertions, 0 deletions

diff --git a/libc/src/string/strcpy/strcpy_test.cpp b/libc/src/string/strcpy/strcpy_test.cpp
new file mode 100644
index 00000000000..48f55f24649
--- /dev/null
+++ b/libc/src/string/strcpy/strcpy_test.cpp
@@ -0,0 +1,40 @@
+//===----------------------- Unittests for strcpy -------------------------===//
+//
+// 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 <string>
+
+#include "src/string/strcpy/strcpy.h"
+#include "gtest/gtest.h"
+
+TEST(StrCpyTest, EmptyDest) {
+  std::string abc = "abc";
+  char *dest = new char[4];
+
+  char *result = __llvm_libc::strcpy(dest, abc.c_str());
+  ASSERT_EQ(dest, result);
+  ASSERT_EQ(std::string(dest), abc);
+  ASSERT_EQ(std::string(dest).size(), abc.size());
+
+  delete[] dest;
+}
+
+TEST(StrCpyTest, OffsetDest) {
+  std::string abc = "abc";
+  char *dest = new char[7];
+
+  dest[0] = 'x';
+  dest[1] = 'y';
+  dest[2] = 'z';
+
+  char *result = __llvm_libc::strcpy(dest + 3, abc.c_str());
+  ASSERT_EQ(dest + 3, result);
+  ASSERT_EQ(std::string(dest), std::string("xyz") + abc);
+  ASSERT_EQ(std::string(dest).size(), abc.size() + 3);
+
+  delete[] dest;
+}