1/* Copyright (C) 1995-2023 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <wchar.h>
19
20
21/* Append no more than N wide-character of SRC onto DEST. */
22wchar_t *
23__wcsncat_chk (wchar_t *dest, const wchar_t *src, size_t n, size_t destlen)
24{
25 wchar_t c;
26 wchar_t * const s = dest;
27
28 /* Find the end of DEST. */
29 do
30 {
31 if (__glibc_unlikely (destlen-- == 0))
32 __chk_fail ();
33 c = *dest++;
34 }
35 while (c != L'\0');
36
37 /* Make DEST point before next character, so we can increment
38 it while memory is read (wins on pipelined cpus). */
39 ++destlen;
40 dest -= 2;
41
42 if (n >= 4)
43 {
44 size_t n4 = n >> 2;
45 do
46 {
47 if (__glibc_unlikely (destlen-- == 0))
48 __chk_fail ();
49 c = *src++;
50 *++dest = c;
51 if (c == L'\0')
52 return s;
53 if (__glibc_unlikely (destlen-- == 0))
54 __chk_fail ();
55 c = *src++;
56 *++dest = c;
57 if (c == L'\0')
58 return s;
59 if (__glibc_unlikely (destlen-- == 0))
60 __chk_fail ();
61 c = *src++;
62 *++dest = c;
63 if (c == L'\0')
64 return s;
65 if (__glibc_unlikely (destlen-- == 0))
66 __chk_fail ();
67 c = *src++;
68 *++dest = c;
69 if (c == L'\0')
70 return s;
71 } while (--n4 > 0);
72 n &= 3;
73 }
74
75 while (n > 0)
76 {
77 if (__glibc_unlikely (destlen-- == 0))
78 __chk_fail ();
79 c = *src++;
80 *++dest = c;
81 if (c == L'\0')
82 return s;
83 n--;
84 }
85
86 if (c != L'\0')
87 {
88 if (__glibc_unlikely (destlen-- == 0))
89 __chk_fail ();
90 *++dest = L'\0';
91 }
92
93 return s;
94}
95