1//===-- Unittests for strncpy ---------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "src/__support/CPP/span.h"
10#include "src/string/strncpy.h"
11#include "test/UnitTest/Test.h"
12#include <stddef.h> // For size_t.
13
14class LlvmLibcStrncpyTest : public LIBC_NAMESPACE::testing::Test {
15public:
16 void check_strncpy(LIBC_NAMESPACE::cpp::span<char> dst,
17 const LIBC_NAMESPACE::cpp::span<const char> src, size_t n,
18 const LIBC_NAMESPACE::cpp::span<const char> expected) {
19 // Making sure we don't overflow buffer.
20 ASSERT_GE(dst.size(), n);
21 // Making sure strncpy returns dst.
22 ASSERT_EQ(LIBC_NAMESPACE::strncpy(dst.data(), src.data(), n), dst.data());
23 // Expected must be of the same size as dst.
24 ASSERT_EQ(dst.size(), expected.size());
25 // Expected and dst are the same.
26 for (size_t i = 0; i < expected.size(); ++i)
27 ASSERT_EQ(expected[i], dst[i]);
28 }
29};
30
31TEST_F(LlvmLibcStrncpyTest, Untouched) {
32 char dst[] = {'a', 'b'};
33 const char src[] = {'x', '\0'};
34 const char expected[] = {'a', 'b'};
35 check_strncpy(dst, src, 0, expected);
36}
37
38TEST_F(LlvmLibcStrncpyTest, CopyOne) {
39 char dst[] = {'a', 'b'};
40 const char src[] = {'x', 'y'};
41 const char expected[] = {'x', 'b'}; // no \0 is appended
42 check_strncpy(dst, src, 1, expected);
43}
44
45TEST_F(LlvmLibcStrncpyTest, CopyNull) {
46 char dst[] = {'a', 'b'};
47 const char src[] = {'\0', 'y'};
48 const char expected[] = {'\0', 'b'};
49 check_strncpy(dst, src, 1, expected);
50}
51
52TEST_F(LlvmLibcStrncpyTest, CopyPastSrc) {
53 char dst[] = {'a', 'b'};
54 const char src[] = {'\0', 'y'};
55 const char expected[] = {'\0', '\0'};
56 check_strncpy(dst, src, 2, expected);
57}
58

source code of libc/test/src/string/strncpy_test.cpp