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5be86566 PA |
1 | /* -*- linux-c -*- ------------------------------------------------------- * |
2 | * | |
3 | * Copyright (C) 1991, 1992 Linus Torvalds | |
4 | * Copyright 2007 rPath, Inc. - All Rights Reserved | |
5 | * | |
6 | * This file is part of the Linux kernel, and is made available under | |
7 | * the terms of the GNU General Public License version 2. | |
8 | * | |
9 | * ----------------------------------------------------------------------- */ | |
10 | ||
11 | /* | |
5be86566 PA |
12 | * Very basic string functions |
13 | */ | |
14 | ||
3d379225 VG |
15 | #include <linux/types.h> |
16 | #include "ctype.h" | |
fac69d0e | 17 | #include "string.h" |
5be86566 | 18 | |
18d5e6c3 MD |
19 | /* |
20 | * Undef these macros so that the functions that we provide | |
21 | * here will have the correct names regardless of how string.h | |
22 | * may have chosen to #define them. | |
23 | */ | |
24 | #undef memcpy | |
25 | #undef memset | |
26 | #undef memcmp | |
27 | ||
fb4cac57 VG |
28 | int memcmp(const void *s1, const void *s2, size_t len) |
29 | { | |
117780ee | 30 | bool diff; |
fb4cac57 VG |
31 | asm("repe; cmpsb; setnz %0" |
32 | : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len)); | |
33 | return diff; | |
34 | } | |
35 | ||
5be86566 PA |
36 | int strcmp(const char *str1, const char *str2) |
37 | { | |
38 | const unsigned char *s1 = (const unsigned char *)str1; | |
39 | const unsigned char *s2 = (const unsigned char *)str2; | |
40 | int delta = 0; | |
41 | ||
42 | while (*s1 || *s2) { | |
1c1d046b | 43 | delta = *s1 - *s2; |
5be86566 PA |
44 | if (delta) |
45 | return delta; | |
46 | s1++; | |
47 | s2++; | |
48 | } | |
49 | return 0; | |
50 | } | |
51 | ||
fa97bdf9 PE |
52 | int strncmp(const char *cs, const char *ct, size_t count) |
53 | { | |
54 | unsigned char c1, c2; | |
55 | ||
56 | while (count) { | |
57 | c1 = *cs++; | |
58 | c2 = *ct++; | |
59 | if (c1 != c2) | |
60 | return c1 < c2 ? -1 : 1; | |
61 | if (!c1) | |
62 | break; | |
63 | count--; | |
64 | } | |
65 | return 0; | |
66 | } | |
67 | ||
5be86566 PA |
68 | size_t strnlen(const char *s, size_t maxlen) |
69 | { | |
70 | const char *es = s; | |
71 | while (*es && maxlen) { | |
72 | es++; | |
73 | maxlen--; | |
74 | } | |
75 | ||
76 | return (es - s); | |
77 | } | |
78 | ||
79 | unsigned int atou(const char *s) | |
80 | { | |
81 | unsigned int i = 0; | |
82 | while (isdigit(*s)) | |
83 | i = i * 10 + (*s++ - '0'); | |
84 | return i; | |
85 | } | |
fa97bdf9 PE |
86 | |
87 | /* Works only for digits and letters, but small and fast */ | |
88 | #define TOLOWER(x) ((x) | 0x20) | |
89 | ||
ce0aa5dd YL |
90 | static unsigned int simple_guess_base(const char *cp) |
91 | { | |
92 | if (cp[0] == '0') { | |
93 | if (TOLOWER(cp[1]) == 'x' && isxdigit(cp[2])) | |
94 | return 16; | |
95 | else | |
96 | return 8; | |
97 | } else { | |
98 | return 10; | |
99 | } | |
100 | } | |
101 | ||
102 | /** | |
103 | * simple_strtoull - convert a string to an unsigned long long | |
104 | * @cp: The start of the string | |
105 | * @endp: A pointer to the end of the parsed string will be placed here | |
106 | * @base: The number base to use | |
107 | */ | |
108 | ||
fa97bdf9 PE |
109 | unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base) |
110 | { | |
111 | unsigned long long result = 0; | |
112 | ||
ce0aa5dd YL |
113 | if (!base) |
114 | base = simple_guess_base(cp); | |
115 | ||
fa97bdf9 PE |
116 | if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x') |
117 | cp += 2; | |
118 | ||
119 | while (isxdigit(*cp)) { | |
120 | unsigned int value; | |
121 | ||
122 | value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10; | |
123 | if (value >= base) | |
124 | break; | |
125 | result = result * base + value; | |
126 | cp++; | |
127 | } | |
128 | if (endp) | |
129 | *endp = (char *)cp; | |
130 | ||
131 | return result; | |
132 | } | |
291f3632 | 133 | |
d52e7d5a BH |
134 | long simple_strtol(const char *cp, char **endp, unsigned int base) |
135 | { | |
136 | if (*cp == '-') | |
137 | return -simple_strtoull(cp + 1, endp, base); | |
138 | ||
139 | return simple_strtoull(cp, endp, base); | |
140 | } | |
141 | ||
291f3632 MF |
142 | /** |
143 | * strlen - Find the length of a string | |
144 | * @s: The string to be sized | |
145 | */ | |
146 | size_t strlen(const char *s) | |
147 | { | |
148 | const char *sc; | |
149 | ||
150 | for (sc = s; *sc != '\0'; ++sc) | |
151 | /* nothing */; | |
152 | return sc - s; | |
153 | } | |
154 | ||
155 | /** | |
156 | * strstr - Find the first substring in a %NUL terminated string | |
157 | * @s1: The string to be searched | |
158 | * @s2: The string to search for | |
159 | */ | |
160 | char *strstr(const char *s1, const char *s2) | |
161 | { | |
162 | size_t l1, l2; | |
163 | ||
164 | l2 = strlen(s2); | |
165 | if (!l2) | |
166 | return (char *)s1; | |
167 | l1 = strlen(s1); | |
168 | while (l1 >= l2) { | |
169 | l1--; | |
170 | if (!memcmp(s1, s2, l2)) | |
171 | return (char *)s1; | |
172 | s1++; | |
173 | } | |
174 | return NULL; | |
175 | } | |
f2844249 DJ |
176 | |
177 | /** | |
178 | * strchr - Find the first occurrence of the character c in the string s. | |
179 | * @s: the string to be searched | |
180 | * @c: the character to search for | |
181 | */ | |
182 | char *strchr(const char *s, int c) | |
183 | { | |
184 | while (*s != (char)c) | |
185 | if (*s++ == '\0') | |
186 | return NULL; | |
187 | return (char *)s; | |
188 | } |