Rev 4872 | Details | Compare with Previous | Last modification | View Log | RSS feed
Rev | Author | Line No. | Line |
---|---|---|---|
4349 | Serge | 1 | /* |
2 | FUNCTION |
||
3 | < |
||
4 | |||
5 | INDEX |
||
6 | strcmp |
||
7 | |||
8 | ANSI_SYNOPSIS |
||
9 | #include |
||
10 | int strcmp(const char *<[a]>, const char *<[b]>); |
||
11 | |||
12 | TRAD_SYNOPSIS |
||
13 | #include |
||
14 | int strcmp(<[a]>, <[b]>) |
||
15 | char *<[a]>; |
||
16 | char *<[b]>; |
||
17 | |||
18 | DESCRIPTION |
||
19 | < |
||
20 | the string at <[b]>. |
||
21 | |||
22 | RETURNS |
||
23 | If <<*<[a]>>> sorts lexicographically after <<*<[b]>>>, |
||
24 | < |
||
25 | strings match, < |
||
26 | sorts lexicographically before <<*<[b]>>>, < |
||
27 | number less than zero. |
||
28 | |||
29 | PORTABILITY |
||
30 | < |
||
31 | |||
32 | < |
||
33 | |||
34 | QUICKREF |
||
35 | strcmp ansi pure |
||
36 | */ |
||
37 | |||
38 | #include |
||
39 | #include |
||
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 | } |