| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* Copyright (C) 1993-2015 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 | <http://www.gnu.org/licenses/>. */ |
| 17 | |
| 18 | /* This is almost copied from strncpy.c, written by Torbjorn Granlund. */ |
| 19 | |
| 20 | #ifdef HAVE_CONFIG_H |
| 21 | # include <config.h> |
| 22 | #endif |
| 23 | |
| 24 | #ifdef _LIBC |
| 25 | # include <string.h> |
| 26 | #else |
| 27 | # include <sys/types.h> |
| 28 | #endif |
| 29 | |
| 30 | #ifndef STPNCPY |
| 31 | # ifdef weak_alias |
| 32 | # define STPNCPY __stpncpy |
| 33 | weak_alias (__stpncpy, stpncpy) |
| 34 | # else |
| 35 | # define STPNCPY stpncpy |
| 36 | # endif |
| 37 | #endif |
| 38 | |
| 39 | /* Copy no more than N characters of SRC to DEST, returning the address of |
| 40 | the terminating '\0' in DEST, if any, or else DEST + N. */ |
| 41 | char * |
| 42 | STPNCPY (char *dest, const char *src, size_t n) |
| 43 | { |
| 44 | char c; |
| 45 | char *s = dest; |
| 46 | |
| 47 | if (n >= 4) |
| 48 | { |
| 49 | size_t n4 = n >> 2; |
| 50 | |
| 51 | for (;;) |
| 52 | { |
| 53 | c = *src++; |
| 54 | *dest++ = c; |
| 55 | if (c == '\0') |
| 56 | break; |
| 57 | c = *src++; |
| 58 | *dest++ = c; |
| 59 | if (c == '\0') |
| 60 | break; |
| 61 | c = *src++; |
| 62 | *dest++ = c; |
| 63 | if (c == '\0') |
| 64 | break; |
| 65 | c = *src++; |
| 66 | *dest++ = c; |
| 67 | if (c == '\0') |
| 68 | break; |
| 69 | if (--n4 == 0) |
| 70 | goto last_chars; |
| 71 | } |
| 72 | n -= dest - s; |
| 73 | goto zero_fill; |
| 74 | } |
| 75 | |
| 76 | last_chars: |
| 77 | n &= 3; |
| 78 | if (n == 0) |
| 79 | return dest; |
| 80 | |
| 81 | for (;;) |
| 82 | { |
| 83 | c = *src++; |
| 84 | --n; |
| 85 | *dest++ = c; |
| 86 | if (c == '\0') |
| 87 | break; |
| 88 | if (n == 0) |
| 89 | return dest; |
| 90 | } |
| 91 | |
| 92 | zero_fill: |
| 93 | while (n-- > 0) |
| 94 | dest[n] = '\0'; |
| 95 | |
| 96 | return dest - 1; |
| 97 | } |
| 98 | #ifdef weak_alias |
| 99 | libc_hidden_def (__stpncpy) |
| 100 | #endif |