1 /*
2 * Copyright (c) 1987 Regents of the University of California.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms are permitted
6 * provided that this notice is preserved and that due credit is given
7 * to the University of California at Berkeley. The name of the University
8 * may not be used to endorse or promote products derived from this
9 * software without specific written prior permission. This software
10 * is provided ``as is'' without express or implied warranty.
11 */
12
13 #include "ascii_strcasecmp.h"
14
15 /*
16 * This array maps upper-case ASCII letters to their lower-case
17 * equivalents; all other byte values are mapped to themselves,
18 * so this is locale-independent and intended to be locale-independent,
19 * to avoid issues with, for example, "i" and "I" not being lower-case
20 * and upper-case versions of the same letter in Turkish, where
21 * there are separate "i with dot" and "i without dot" letters.
22 */
23 static const unsigned char charmap[] = {
24 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
25 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
26 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
27 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
28 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
29 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
30 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
31 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
32 0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
33 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
34 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
35 0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
36 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
37 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
38 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
39 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,
40 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
41 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
42 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
43 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
44 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
45 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
46 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7,
47 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
48 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
49 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
50 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,
51 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,
52 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
53 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
54 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
55 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff,
56 };
57
58 int
ascii_strcasecmp(const char * s1,const char * s2)59 ascii_strcasecmp(const char *s1, const char *s2)
60 {
61 register const unsigned char *cm = charmap,
62 *us1 = (const unsigned char *)s1,
63 *us2 = (const unsigned char *)s2;
64
65 while (cm[*us1] == cm[*us2++])
66 if (*us1++ == '\0')
67 return(0);
68 return(cm[*us1] - cm[*--us2]);
69 }
70
71 int
ascii_strncasecmp(const char * s1,const char * s2,register size_t n)72 ascii_strncasecmp(const char *s1, const char *s2, register size_t n)
73 {
74 register const unsigned char *cm = charmap,
75 *us1 = (const unsigned char *)s1,
76 *us2 = (const unsigned char *)s2;
77
78 for (;;) {
79 if (n == 0) {
80 /*
81 * We've run out of characters that we should
82 * compare, and they've all been equal; return
83 * 0, to indicate that the prefixes are the
84 * same.
85 */
86 return(0);
87 }
88 if (cm[*us1] != cm[*us2++]) {
89 /*
90 * We've found a mismatch.
91 */
92 break;
93 }
94 if (*us1++ == '\0') {
95 /*
96 * We've run out of characters *to* compare,
97 * and they've all been equal; return 0, to
98 * indicate that the strings are the same.
99 */
100 return(0);
101 }
102 n--;
103 }
104 return(cm[*us1] - cm[*--us2]);
105 }
106