| xf.li | bdd93d5 | 2023-05-12 07:10:14 -0700 | [diff] [blame] | 1 | /* Copyright (C) 1991-2016 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 | #include <string.h> |
| 19 | #include <memcopy.h> |
| 20 | |
| 21 | #undef strncmp |
| 22 | |
| 23 | #ifndef STRNCMP |
| 24 | #define STRNCMP strncmp |
| 25 | #endif |
| 26 | |
| 27 | /* Compare no more than N characters of S1 and S2, |
| 28 | returning less than, equal to or greater than zero |
| 29 | if S1 is lexicographically less than, equal to or |
| 30 | greater than S2. */ |
| 31 | int |
| 32 | STRNCMP (const char *s1, const char *s2, size_t n) |
| 33 | { |
| 34 | unsigned char c1 = '\0'; |
| 35 | unsigned char c2 = '\0'; |
| 36 | |
| 37 | if (n >= 4) |
| 38 | { |
| 39 | size_t n4 = n >> 2; |
| 40 | do |
| 41 | { |
| 42 | c1 = (unsigned char) *s1++; |
| 43 | c2 = (unsigned char) *s2++; |
| 44 | if (c1 == '\0' || c1 != c2) |
| 45 | return c1 - c2; |
| 46 | c1 = (unsigned char) *s1++; |
| 47 | c2 = (unsigned char) *s2++; |
| 48 | if (c1 == '\0' || c1 != c2) |
| 49 | return c1 - c2; |
| 50 | c1 = (unsigned char) *s1++; |
| 51 | c2 = (unsigned char) *s2++; |
| 52 | if (c1 == '\0' || c1 != c2) |
| 53 | return c1 - c2; |
| 54 | c1 = (unsigned char) *s1++; |
| 55 | c2 = (unsigned char) *s2++; |
| 56 | if (c1 == '\0' || c1 != c2) |
| 57 | return c1 - c2; |
| 58 | } while (--n4 > 0); |
| 59 | n &= 3; |
| 60 | } |
| 61 | |
| 62 | while (n > 0) |
| 63 | { |
| 64 | c1 = (unsigned char) *s1++; |
| 65 | c2 = (unsigned char) *s2++; |
| 66 | if (c1 == '\0' || c1 != c2) |
| 67 | return c1 - c2; |
| 68 | n--; |
| 69 | } |
| 70 | |
| 71 | return c1 - c2; |
| 72 | } |
| 73 | |
| 74 | libc_hidden_builtin_def (STRNCMP) |