xref: /kernel/linux/linux-5.10/arch/s390/boot/string.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/ctype.h>
3#include <linux/kernel.h>
4#include <linux/errno.h>
5#undef CONFIG_KASAN
6#include "../lib/string.c"
7
8int strncmp(const char *cs, const char *ct, size_t count)
9{
10	unsigned char c1, c2;
11
12	while (count) {
13		c1 = *cs++;
14		c2 = *ct++;
15		if (c1 != c2)
16			return c1 < c2 ? -1 : 1;
17		if (!c1)
18			break;
19		count--;
20	}
21	return 0;
22}
23
24char *skip_spaces(const char *str)
25{
26	while (isspace(*str))
27		++str;
28	return (char *)str;
29}
30
31char *strim(char *s)
32{
33	size_t size;
34	char *end;
35
36	size = strlen(s);
37	if (!size)
38		return s;
39
40	end = s + size - 1;
41	while (end >= s && isspace(*end))
42		end--;
43	*(end + 1) = '\0';
44
45	return skip_spaces(s);
46}
47
48/* Works only for digits and letters, but small and fast */
49#define TOLOWER(x) ((x) | 0x20)
50
51static unsigned int simple_guess_base(const char *cp)
52{
53	if (cp[0] == '0') {
54		if (TOLOWER(cp[1]) == 'x' && isxdigit(cp[2]))
55			return 16;
56		else
57			return 8;
58	} else {
59		return 10;
60	}
61}
62
63/**
64 * simple_strtoull - convert a string to an unsigned long long
65 * @cp: The start of the string
66 * @endp: A pointer to the end of the parsed string will be placed here
67 * @base: The number base to use
68 */
69
70unsigned long long simple_strtoull(const char *cp, char **endp,
71				   unsigned int base)
72{
73	unsigned long long result = 0;
74
75	if (!base)
76		base = simple_guess_base(cp);
77
78	if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x')
79		cp += 2;
80
81	while (isxdigit(*cp)) {
82		unsigned int value;
83
84		value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10;
85		if (value >= base)
86			break;
87		result = result * base + value;
88		cp++;
89	}
90	if (endp)
91		*endp = (char *)cp;
92
93	return result;
94}
95
96long simple_strtol(const char *cp, char **endp, unsigned int base)
97{
98	if (*cp == '-')
99		return -simple_strtoull(cp + 1, endp, base);
100
101	return simple_strtoull(cp, endp, base);
102}
103
104int kstrtobool(const char *s, bool *res)
105{
106	if (!s)
107		return -EINVAL;
108
109	switch (s[0]) {
110	case 'y':
111	case 'Y':
112	case '1':
113		*res = true;
114		return 0;
115	case 'n':
116	case 'N':
117	case '0':
118		*res = false;
119		return 0;
120	case 'o':
121	case 'O':
122		switch (s[1]) {
123		case 'n':
124		case 'N':
125			*res = true;
126			return 0;
127		case 'f':
128		case 'F':
129			*res = false;
130			return 0;
131		default:
132			break;
133		}
134	default:
135		break;
136	}
137
138	return -EINVAL;
139}
140