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*tcsncat_s.inl - general implementation of _tcscpy_s
7*
8
9*
10*Purpose:
11* This file contains the general algorithm for strncat_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 _VALIDATE_POINTER_RESET_STRING(_SRC, _DEST, _SIZE);
32 }
33
34 p = _DEST;
35 available = _SIZE;
36 while (available > 0 && *p != 0)
37 {
38 p++;
39 available--;
40 }
41
42 if (available == 0)
43 {
44 _RESET_STRING(_DEST, _SIZE);
45 _RETURN_DEST_NOT_NULL_TERMINATED(_DEST, _SIZE);
46 }
47
48 if (_COUNT == _TRUNCATE)
49 {
50 while ((*p++ = *_SRC++) != 0 && --available > 0)
51 {
52 }
53 }
54 else
55 {
56 _ASSERT_EXPR((!_CrtGetCheckCount() || _COUNT < available), "Buffer is too small");
57
58 while (_COUNT > 0 && (*p++ = *_SRC++) != 0 && --available > 0)
59 {
60 _COUNT--;
61 }
62 if (_COUNT == 0)
63 {
64 *p = 0;
65 }
66 }
67
68 if (available == 0)
69 {
70 if (_COUNT == _TRUNCATE)
71 {
72 _DEST[_SIZE - 1] = 0;
73 _RETURN_TRUNCATE;
74 }
75 _RESET_STRING(_DEST, _SIZE);
76 _RETURN_BUFFER_TOO_SMALL(_DEST, _SIZE);
77 }
78 _FILL_STRING(_DEST, _SIZE, _SIZE - available + 1);
79 _RETURN_NO_ERROR;
80}
81
82