1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
|
/*
* This file is part of the LinuxBIOS project.
*
* Copyright (C) 2007 Uwe Hermann <uwe@hermann-uwe.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef STRING_H
#define STRING_H
#include <stdlib.h>
/* Prototypes for functions from lib/mem.c. */
extern void *memcpy(void *dest, const void *src, int len);
extern void *memmove(void *dest, const void *src, int len);
extern void *memset(void *v, unsigned char a, int len);
extern int memcmp(const void *s1, const void *s2, int len);
/* Prototypes for functions from console/vsprintf.c. */
extern int sprintf(char *buf, const char *fmt, ...);
/**
* Calculate the length of a fixed-size string.
*
* @param str The input string.
* @param maxlen Return at most maxlen characters as length of the string.
* @return The length of the string, not including the final NUL character.
* The maximum length returned is maxlen.
*/
static inline size_t strnlen(const char *str, size_t maxlen)
{
size_t len = 0;
/* NULL and empty strings have length 0. */
if (!str)
return 0;
/* Loop until we find a NUL character, or maxlen is reached. */
while ((*str++ != '\0') && (len < maxlen))
len++;
return len;
}
/**
* Calculate the length of a string.
*
* @param str The input string.
* @return The length of the string, not including the final NUL character.
*/
static inline size_t strlen(const char *str)
{
size_t len = 0;
/* NULL and empty strings have length 0. */
if (!str)
return 0;
/* Loop until we find a NUL character. */
while (*str++ != '\0')
len++;
return len;
}
/**
* Compare two strings.
*
* @param s1 The first string.
* @param s2 The second string.
* @return Returns a value less than zero, if s1 is shorter than s2. Returns
* zero, if s1 equals s2. Returns a value greater than zero, if
* s1 is longer than s2.
*/
static inline int strcmp(const char *s1, const char *s2)
{
char c1, c2;
/* Set c1 == c2, so that we can enter the while loop. */
c1 = 0;
c2 = 0;
/* Compare characters until they differ, or one of the strings ends. */
while (c1 == c2) {
/* Read the next character from each string. */
c1 = *s1++;
c2 = *s2++;
/* Return something negative (if s1 is shorter than s2), or
zero (if s1 equals s2). */
if (c1 == '\0')
return c1 - c2;
}
/* Return someting positive (if s1 is longer than s2), or zero (if s1
and s2 are equal). */
return c1 - c2;
}
#endif /* STRING_H */
|
