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688903eb | 1 | /* Copyright (C) 1991-2018 Free Software Foundation, Inc. |
6d52618b | 2 | This file is part of the GNU C Library. |
28f540f4 | 3 | |
6d52618b | 4 | The GNU C Library is free software; you can redistribute it and/or |
41bdb6e2 AJ |
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. | |
28f540f4 | 8 | |
6d52618b UD |
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 | |
41bdb6e2 | 12 | Lesser General Public License for more details. |
28f540f4 | 13 | |
41bdb6e2 | 14 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 PE |
15 | License along with the GNU C Library; if not, see |
16 | <http://www.gnu.org/licenses/>. */ | |
28f540f4 | 17 | |
28f540f4 RM |
18 | #include <string.h> |
19 | #include <memcopy.h> | |
20 | ||
9a0a462c UD |
21 | #undef strncmp |
22 | ||
772f4e6a L |
23 | #ifndef STRNCMP |
24 | #define STRNCMP strncmp | |
25 | #endif | |
26 | ||
28f540f4 RM |
27 | /* Compare no more than N characters of S1 and S2, |
28 | returning less than, equal to or greater than zero | |
6d52618b | 29 | if S1 is lexicographically less than, equal to or |
28f540f4 RM |
30 | greater than S2. */ |
31 | int | |
772f4e6a | 32 | STRNCMP (const char *s1, const char *s2, size_t n) |
28f540f4 | 33 | { |
50f81fd7 DM |
34 | unsigned char c1 = '\0'; |
35 | unsigned char c2 = '\0'; | |
28f540f4 RM |
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 | } | |
772f4e6a L |
73 | |
74 | libc_hidden_builtin_def (STRNCMP) |