1// Licensed to the .NET Foundation under one or more agreements.
2// The .NET Foundation licenses this file to you under the MIT license.
3// See the LICENSE file in the project root for more information.
4
5/***
6*tcsncpy_s.inl - general implementation of _tcsncpy_s
7*
8
9*
10*Purpose:
11* This file contains the general algorithm for strncpy_s and its variants.
12*
13****/
14
15_FUNC_PROLOGUE
16errno_t __cdecl _FUNC_NAME(_CHAR *_DEST, size_t _SIZE, const _CHAR *_SRC, size_t _COUNT)
17{
18 _CHAR *p;
19 size_t available;
20
21 if (_COUNT == 0 && _DEST == NULL && _SIZE == 0)
22 {
23 /* this case is allowed; nothing to do */
24 _RETURN_NO_ERROR;
25 }
26
27 /* validation section */
28 _VALIDATE_STRING(_DEST, _SIZE);
29 if (_COUNT == 0)
30 {
31 /* notice that the source string pointer can be NULL in this case */
32 _RESET_STRING(_DEST, _SIZE);
33 _RETURN_NO_ERROR;
34 }
35 _VALIDATE_POINTER_RESET_STRING(_SRC, _DEST, _SIZE);
36
37 p = _DEST;
38 available = _SIZE;
39 if (_COUNT == _TRUNCATE)
40 {
41 while ((*p++ = *_SRC++) != 0 && --available > 0)
42 {
43 }
44 }
45 else
46 {
47 _ASSERT_EXPR((!_CrtGetCheckCount() || _COUNT < _SIZE), "Buffer is too small");
48
49 while ((*p++ = *_SRC++) != 0 && --available > 0 && --_COUNT > 0)
50 {
51 }
52 if (_COUNT == 0)
53 {
54 *p = 0;
55 }
56 }
57
58 if (available == 0)
59 {
60 if (_COUNT == _TRUNCATE)
61 {
62 _DEST[_SIZE - 1] = 0;
63 _RETURN_TRUNCATE;
64 }
65 _RESET_STRING(_DEST, _SIZE);
66 _RETURN_BUFFER_TOO_SMALL(_DEST, _SIZE);
67 }
68 _FILL_STRING(_DEST, _SIZE, _SIZE - available + 1);
69 _RETURN_NO_ERROR;
70}
71
72