1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Taken from:
4 * linux/lib/string.c
5 *
6 * Copyright (C) 1991, 1992 Linus Torvalds
7 */
8
9 #include <linux/ctype.h>
10 #include <linux/kernel.h>
11 #include <linux/types.h>
12 #include <linux/string.h>
13
14 #ifndef EFI_HAVE_STRLEN
15 /**
16 * strlen - Find the length of a string
17 * @s: The string to be sized
18 */
strlen(const char * s)19 size_t strlen(const char *s)
20 {
21 const char *sc;
22
23 for (sc = s; *sc != '\0'; ++sc)
24 /* nothing */;
25 return sc - s;
26 }
27 #endif
28
29 #ifndef EFI_HAVE_STRNLEN
30 /**
31 * strnlen - Find the length of a length-limited string
32 * @s: The string to be sized
33 * @count: The maximum number of bytes to search
34 */
strnlen(const char * s,size_t count)35 size_t strnlen(const char *s, size_t count)
36 {
37 const char *sc;
38
39 for (sc = s; count-- && *sc != '\0'; ++sc)
40 /* nothing */;
41 return sc - s;
42 }
43 #endif
44
45 /**
46 * strstr - Find the first substring in a %NUL terminated string
47 * @s1: The string to be searched
48 * @s2: The string to search for
49 */
strstr(const char * s1,const char * s2)50 char *strstr(const char *s1, const char *s2)
51 {
52 size_t l1, l2;
53
54 l2 = strlen(s2);
55 if (!l2)
56 return (char *)s1;
57 l1 = strlen(s1);
58 while (l1 >= l2) {
59 l1--;
60 if (!memcmp(s1, s2, l2))
61 return (char *)s1;
62 s1++;
63 }
64 return NULL;
65 }
66
67 #ifndef EFI_HAVE_STRCMP
68 /**
69 * strcmp - Compare two strings
70 * @cs: One string
71 * @ct: Another string
72 */
strcmp(const char * cs,const char * ct)73 int strcmp(const char *cs, const char *ct)
74 {
75 unsigned char c1, c2;
76
77 while (1) {
78 c1 = *cs++;
79 c2 = *ct++;
80 if (c1 != c2)
81 return c1 < c2 ? -1 : 1;
82 if (!c1)
83 break;
84 }
85 return 0;
86 }
87 #endif
88
89 /**
90 * strncmp - Compare two length-limited strings
91 * @cs: One string
92 * @ct: Another string
93 * @count: The maximum number of bytes to compare
94 */
strncmp(const char * cs,const char * ct,size_t count)95 int strncmp(const char *cs, const char *ct, size_t count)
96 {
97 unsigned char c1, c2;
98
99 while (count) {
100 c1 = *cs++;
101 c2 = *ct++;
102 if (c1 != c2)
103 return c1 < c2 ? -1 : 1;
104 if (!c1)
105 break;
106 count--;
107 }
108 return 0;
109 }
110
111 /* Works only for digits and letters, but small and fast */
112 #define TOLOWER(x) ((x) | 0x20)
113
simple_guess_base(const char * cp)114 static unsigned int simple_guess_base(const char *cp)
115 {
116 if (cp[0] == '0') {
117 if (TOLOWER(cp[1]) == 'x' && isxdigit(cp[2]))
118 return 16;
119 else
120 return 8;
121 } else {
122 return 10;
123 }
124 }
125
126 /**
127 * simple_strtoull - convert a string to an unsigned long long
128 * @cp: The start of the string
129 * @endp: A pointer to the end of the parsed string will be placed here
130 * @base: The number base to use
131 */
132
simple_strtoull(const char * cp,char ** endp,unsigned int base)133 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
134 {
135 unsigned long long result = 0;
136
137 if (!base)
138 base = simple_guess_base(cp);
139
140 if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x')
141 cp += 2;
142
143 while (isxdigit(*cp)) {
144 unsigned int value;
145
146 value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10;
147 if (value >= base)
148 break;
149 result = result * base + value;
150 cp++;
151 }
152 if (endp)
153 *endp = (char *)cp;
154
155 return result;
156 }
157
simple_strtol(const char * cp,char ** endp,unsigned int base)158 long simple_strtol(const char *cp, char **endp, unsigned int base)
159 {
160 if (*cp == '-')
161 return -simple_strtoull(cp + 1, endp, base);
162
163 return simple_strtoull(cp, endp, base);
164 }
165
166 #ifdef CONFIG_EFI_PARAMS_FROM_FDT
167 #ifndef EFI_HAVE_STRRCHR
168 /**
169 * strrchr - Find the last occurrence of a character in a string
170 * @s: The string to be searched
171 * @c: The character to search for
172 */
strrchr(const char * s,int c)173 char *strrchr(const char *s, int c)
174 {
175 const char *last = NULL;
176 do {
177 if (*s == (char)c)
178 last = s;
179 } while (*s++);
180 return (char *)last;
181 }
182 #endif
183 #ifndef EFI_HAVE_MEMCHR
184 /**
185 * memchr - Find a character in an area of memory.
186 * @s: The memory area
187 * @c: The byte to search for
188 * @n: The size of the area.
189 *
190 * returns the address of the first occurrence of @c, or %NULL
191 * if @c is not found
192 */
memchr(const void * s,int c,size_t n)193 void *memchr(const void *s, int c, size_t n)
194 {
195 const unsigned char *p = s;
196 while (n-- != 0) {
197 if ((unsigned char)c == *p++) {
198 return (void *)(p - 1);
199 }
200 }
201 return NULL;
202 }
203 #endif
204 #endif
205