1/* Copyright (C) 1995-2019 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19#include <wchar.h>
20
21#ifndef WCSNCAT
22# define WCSNCAT wcsncat
23#endif
24
25/* Append no more than N wide-character of SRC onto DEST. */
26wchar_t *
27WCSNCAT (wchar_t *dest, const wchar_t *src, size_t n)
28{
29 wchar_t c;
30 wchar_t * const s = dest;
31
32 /* Find the end of DEST. */
33 do
34 c = *dest++;
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 dest -= 2;
40
41 if (n >= 4)
42 {
43 size_t n4 = n >> 2;
44 do
45 {
46 c = *src++;
47 *++dest = c;
48 if (c == L'\0')
49 return s;
50 c = *src++;
51 *++dest = c;
52 if (c == L'\0')
53 return s;
54 c = *src++;
55 *++dest = c;
56 if (c == L'\0')
57 return s;
58 c = *src++;
59 *++dest = c;
60 if (c == L'\0')
61 return s;
62 } while (--n4 > 0);
63 n &= 3;
64 }
65
66 while (n > 0)
67 {
68 c = *src++;
69 *++dest = c;
70 if (c == L'\0')
71 return s;
72 n--;
73 }
74
75 if (c != L'\0')
76 *++dest = L'\0';
77
78 return s;
79}
80