diff options
Diffstat (limited to 'firmware/common/strcmp.c')
-rw-r--r-- | firmware/common/strcmp.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/firmware/common/strcmp.c b/firmware/common/strcmp.c new file mode 100644 index 0000000000..81d65272ec --- /dev/null +++ b/firmware/common/strcmp.c | |||
@@ -0,0 +1,106 @@ | |||
1 | /* | ||
2 | FUNCTION | ||
3 | <<strcmp>>---character string compare | ||
4 | |||
5 | INDEX | ||
6 | strcmp | ||
7 | |||
8 | ANSI_SYNOPSIS | ||
9 | #include <string.h> | ||
10 | int strcmp(const char *<[a]>, const char *<[b]>); | ||
11 | |||
12 | TRAD_SYNOPSIS | ||
13 | #include <string.h> | ||
14 | int strcmp(<[a]>, <[b]>) | ||
15 | char *<[a]>; | ||
16 | char *<[b]>; | ||
17 | |||
18 | DESCRIPTION | ||
19 | <<strcmp>> compares the string at <[a]> to | ||
20 | the string at <[b]>. | ||
21 | |||
22 | RETURNS | ||
23 | If <<*<[a]>>> sorts lexicographically after <<*<[b]>>>, | ||
24 | <<strcmp>> returns a number greater than zero. If the two | ||
25 | strings match, <<strcmp>> returns zero. If <<*<[a]>>> | ||
26 | sorts lexicographically before <<*<[b]>>>, <<strcmp>> returns a | ||
27 | number less than zero. | ||
28 | |||
29 | PORTABILITY | ||
30 | <<strcmp>> is ANSI C. | ||
31 | |||
32 | <<strcmp>> requires no supporting OS subroutines. | ||
33 | |||
34 | QUICKREF | ||
35 | strcmp ansi pure | ||
36 | */ | ||
37 | |||
38 | #include <string.h> | ||
39 | #include <limits.h> | ||
40 | |||
41 | /* Nonzero if either X or Y is not aligned on a "long" boundary. */ | ||
42 | #define UNALIGNED(X, Y) \ | ||
43 | (((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1))) | ||
44 | |||
45 | /* DETECTNULL returns nonzero if (long)X contains a NULL byte. */ | ||
46 | #if LONG_MAX == 2147483647L | ||
47 | #define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080) | ||
48 | #else | ||
49 | #if LONG_MAX == 9223372036854775807L | ||
50 | #define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080) | ||
51 | #else | ||
52 | #error long int is not a 32bit or 64bit type. | ||
53 | #endif | ||
54 | #endif | ||
55 | |||
56 | #ifndef DETECTNULL | ||
57 | #error long int is not a 32bit or 64bit byte | ||
58 | #endif | ||
59 | |||
60 | int | ||
61 | _DEFUN (strcmp, (s1, s2), | ||
62 | _CONST char *s1 _AND | ||
63 | _CONST char *s2) | ||
64 | { | ||
65 | #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) | ||
66 | while (*s1 != '\0' && *s1 == *s2) | ||
67 | { | ||
68 | s1++; | ||
69 | s2++; | ||
70 | } | ||
71 | |||
72 | return (*(unsigned char *) s1) - (*(unsigned char *) s2); | ||
73 | #else | ||
74 | unsigned long *a1; | ||
75 | unsigned long *a2; | ||
76 | |||
77 | /* If s1 or s2 are unaligned, then compare bytes. */ | ||
78 | if (!UNALIGNED (s1, s2)) | ||
79 | { | ||
80 | /* If s1 and s2 are word-aligned, compare them a word at a time. */ | ||
81 | a1 = (unsigned long*)s1; | ||
82 | a2 = (unsigned long*)s2; | ||
83 | while (*a1 == *a2) | ||
84 | { | ||
85 | /* To get here, *a1 == *a2, thus if we find a null in *a1, | ||
86 | then the strings must be equal, so return zero. */ | ||
87 | if (DETECTNULL (*a1)) | ||
88 | return 0; | ||
89 | |||
90 | a1++; | ||
91 | a2++; | ||
92 | } | ||
93 | |||
94 | /* A difference was detected in last few bytes of s1, so search bytewise */ | ||
95 | s1 = (char*)a1; | ||
96 | s2 = (char*)a2; | ||
97 | } | ||
98 | |||
99 | while (*s1 != '\0' && *s1 == *s2) | ||
100 | { | ||
101 | s1++; | ||
102 | s2++; | ||
103 | } | ||
104 | return (*(unsigned char *) s1) - (*(unsigned char *) s2); | ||
105 | #endif /* not PREFER_SIZE_OVER_SPEED */ | ||
106 | } | ||