xref: /openbmc/linux/tools/lib/string.c (revision b830f94f)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/tools/lib/string.c
4  *
5  *  Copied from linux/lib/string.c, where it is:
6  *
7  *  Copyright (C) 1991, 1992  Linus Torvalds
8  *
9  *  More specifically, the first copied function was strtobool, which
10  *  was introduced by:
11  *
12  *  d0f1fed29e6e ("Add a strtobool function matching semantics of existing in kernel equivalents")
13  *  Author: Jonathan Cameron <jic23@cam.ac.uk>
14  */
15 
16 #include <stdlib.h>
17 #include <string.h>
18 #include <errno.h>
19 #include <linux/string.h>
20 #include <linux/ctype.h>
21 #include <linux/compiler.h>
22 
23 /**
24  * memdup - duplicate region of memory
25  *
26  * @src: memory region to duplicate
27  * @len: memory region length
28  */
29 void *memdup(const void *src, size_t len)
30 {
31 	void *p = malloc(len);
32 
33 	if (p)
34 		memcpy(p, src, len);
35 
36 	return p;
37 }
38 
39 /**
40  * strtobool - convert common user inputs into boolean values
41  * @s: input string
42  * @res: result
43  *
44  * This routine returns 0 iff the first character is one of 'Yy1Nn0', or
45  * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL.  Value
46  * pointed to by res is updated upon finding a match.
47  */
48 int strtobool(const char *s, bool *res)
49 {
50 	if (!s)
51 		return -EINVAL;
52 
53 	switch (s[0]) {
54 	case 'y':
55 	case 'Y':
56 	case '1':
57 		*res = true;
58 		return 0;
59 	case 'n':
60 	case 'N':
61 	case '0':
62 		*res = false;
63 		return 0;
64 	case 'o':
65 	case 'O':
66 		switch (s[1]) {
67 		case 'n':
68 		case 'N':
69 			*res = true;
70 			return 0;
71 		case 'f':
72 		case 'F':
73 			*res = false;
74 			return 0;
75 		default:
76 			break;
77 		}
78 	default:
79 		break;
80 	}
81 
82 	return -EINVAL;
83 }
84 
85 /**
86  * strlcpy - Copy a C-string into a sized buffer
87  * @dest: Where to copy the string to
88  * @src: Where to copy the string from
89  * @size: size of destination buffer
90  *
91  * Compatible with *BSD: the result is always a valid
92  * NUL-terminated string that fits in the buffer (unless,
93  * of course, the buffer size is zero). It does not pad
94  * out the result like strncpy() does.
95  *
96  * If libc has strlcpy() then that version will override this
97  * implementation:
98  */
99 size_t __weak strlcpy(char *dest, const char *src, size_t size)
100 {
101 	size_t ret = strlen(src);
102 
103 	if (size) {
104 		size_t len = (ret >= size) ? size - 1 : ret;
105 		memcpy(dest, src, len);
106 		dest[len] = '\0';
107 	}
108 	return ret;
109 }
110 
111 /**
112  * skip_spaces - Removes leading whitespace from @str.
113  * @str: The string to be stripped.
114  *
115  * Returns a pointer to the first non-whitespace character in @str.
116  */
117 char *skip_spaces(const char *str)
118 {
119 	while (isspace(*str))
120 		++str;
121 	return (char *)str;
122 }
123 
124 /**
125  * strim - Removes leading and trailing whitespace from @s.
126  * @s: The string to be stripped.
127  *
128  * Note that the first trailing whitespace is replaced with a %NUL-terminator
129  * in the given string @s. Returns a pointer to the first non-whitespace
130  * character in @s.
131  */
132 char *strim(char *s)
133 {
134 	size_t size;
135 	char *end;
136 
137 	size = strlen(s);
138 	if (!size)
139 		return s;
140 
141 	end = s + size - 1;
142 	while (end >= s && isspace(*end))
143 		end--;
144 	*(end + 1) = '\0';
145 
146 	return skip_spaces(s);
147 }
148 
149 /**
150  * strreplace - Replace all occurrences of character in string.
151  * @s: The string to operate on.
152  * @old: The character being replaced.
153  * @new: The character @old is replaced with.
154  *
155  * Returns pointer to the nul byte at the end of @s.
156  */
157 char *strreplace(char *s, char old, char new)
158 {
159 	for (; *s; ++s)
160 		if (*s == old)
161 			*s = new;
162 	return s;
163 }
164