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#ifdef WCSNCPY
22# define __wcsncpy WCSNCPY
23#endif
24
25/* Copy no more than N wide-characters of SRC to DEST. */
26wchar_t *
27__wcsncpy (wchar_t *dest, const wchar_t *src, size_t n)
28{
29 wint_t c;
30 wchar_t *const s = dest;
31
32 --dest;
33
34 if (n >= 4)
35 {
36 size_t n4 = n >> 2;
37
38 for (;;)
39 {
40 c = *src++;
41 *++dest = c;
42 if (c == L'\0')
43 break;
44 c = *src++;
45 *++dest = c;
46 if (c == L'\0')
47 break;
48 c = *src++;
49 *++dest = c;
50 if (c == L'\0')
51 break;
52 c = *src++;
53 *++dest = c;
54 if (c == L'\0')
55 break;
56 if (--n4 == 0)
57 goto last_chars;
58 }
59 n = n - (dest - s) - 1;
60 if (n == 0)
61 return s;
62 goto zero_fill;
63 }
64
65 last_chars:
66 n &= 3;
67 if (n == 0)
68 return s;
69
70 do
71 {
72 c = *src++;
73 *++dest = c;
74 if (--n == 0)
75 return s;
76 }
77 while (c != L'\0');
78
79 zero_fill:
80 do
81 *++dest = L'\0';
82 while (--n > 0);
83
84 return s;
85}
86#ifndef WCSNCPY
87weak_alias (__wcsncpy, wcsncpy)
88#endif
89