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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 | ||
15 | #include "boot.h" | |
16 | ||
fb4cac57 VG |
17 | /* |
18 | * This file gets included in compressed/string.c which might pull in | |
19 | * string_32.h and which in turn maps memcmp to __builtin_memcmp(). Undo | |
20 | * that first. | |
21 | */ | |
22 | #undef memcmp | |
23 | int memcmp(const void *s1, const void *s2, size_t len) | |
24 | { | |
25 | u8 diff; | |
26 | asm("repe; cmpsb; setnz %0" | |
27 | : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len)); | |
28 | return diff; | |
29 | } | |
30 | ||
5be86566 PA |
31 | int strcmp(const char *str1, const char *str2) |
32 | { | |
33 | const unsigned char *s1 = (const unsigned char *)str1; | |
34 | const unsigned char *s2 = (const unsigned char *)str2; | |
35 | int delta = 0; | |
36 | ||
37 | while (*s1 || *s2) { | |
38 | delta = *s2 - *s1; | |
39 | if (delta) | |
40 | return delta; | |
41 | s1++; | |
42 | s2++; | |
43 | } | |
44 | return 0; | |
45 | } | |
46 | ||
fa97bdf9 PE |
47 | int strncmp(const char *cs, const char *ct, size_t count) |
48 | { | |
49 | unsigned char c1, c2; | |
50 | ||
51 | while (count) { | |
52 | c1 = *cs++; | |
53 | c2 = *ct++; | |
54 | if (c1 != c2) | |
55 | return c1 < c2 ? -1 : 1; | |
56 | if (!c1) | |
57 | break; | |
58 | count--; | |
59 | } | |
60 | return 0; | |
61 | } | |
62 | ||
5be86566 PA |
63 | size_t strnlen(const char *s, size_t maxlen) |
64 | { | |
65 | const char *es = s; | |
66 | while (*es && maxlen) { | |
67 | es++; | |
68 | maxlen--; | |
69 | } | |
70 | ||
71 | return (es - s); | |
72 | } | |
73 | ||
74 | unsigned int atou(const char *s) | |
75 | { | |
76 | unsigned int i = 0; | |
77 | while (isdigit(*s)) | |
78 | i = i * 10 + (*s++ - '0'); | |
79 | return i; | |
80 | } | |
fa97bdf9 PE |
81 | |
82 | /* Works only for digits and letters, but small and fast */ | |
83 | #define TOLOWER(x) ((x) | 0x20) | |
84 | ||
ce0aa5dd YL |
85 | static unsigned int simple_guess_base(const char *cp) |
86 | { | |
87 | if (cp[0] == '0') { | |
88 | if (TOLOWER(cp[1]) == 'x' && isxdigit(cp[2])) | |
89 | return 16; | |
90 | else | |
91 | return 8; | |
92 | } else { | |
93 | return 10; | |
94 | } | |
95 | } | |
96 | ||
97 | /** | |
98 | * simple_strtoull - convert a string to an unsigned long long | |
99 | * @cp: The start of the string | |
100 | * @endp: A pointer to the end of the parsed string will be placed here | |
101 | * @base: The number base to use | |
102 | */ | |
103 | ||
fa97bdf9 PE |
104 | unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base) |
105 | { | |
106 | unsigned long long result = 0; | |
107 | ||
ce0aa5dd YL |
108 | if (!base) |
109 | base = simple_guess_base(cp); | |
110 | ||
fa97bdf9 PE |
111 | if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x') |
112 | cp += 2; | |
113 | ||
114 | while (isxdigit(*cp)) { | |
115 | unsigned int value; | |
116 | ||
117 | value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10; | |
118 | if (value >= base) | |
119 | break; | |
120 | result = result * base + value; | |
121 | cp++; | |
122 | } | |
123 | if (endp) | |
124 | *endp = (char *)cp; | |
125 | ||
126 | return result; | |
127 | } | |
291f3632 MF |
128 | |
129 | /** | |
130 | * strlen - Find the length of a string | |
131 | * @s: The string to be sized | |
132 | */ | |
133 | size_t strlen(const char *s) | |
134 | { | |
135 | const char *sc; | |
136 | ||
137 | for (sc = s; *sc != '\0'; ++sc) | |
138 | /* nothing */; | |
139 | return sc - s; | |
140 | } | |
141 | ||
142 | /** | |
143 | * strstr - Find the first substring in a %NUL terminated string | |
144 | * @s1: The string to be searched | |
145 | * @s2: The string to search for | |
146 | */ | |
147 | char *strstr(const char *s1, const char *s2) | |
148 | { | |
149 | size_t l1, l2; | |
150 | ||
151 | l2 = strlen(s2); | |
152 | if (!l2) | |
153 | return (char *)s1; | |
154 | l1 = strlen(s1); | |
155 | while (l1 >= l2) { | |
156 | l1--; | |
157 | if (!memcmp(s1, s2, l2)) | |
158 | return (char *)s1; | |
159 | s1++; | |
160 | } | |
161 | return NULL; | |
162 | } |