1 /* -*- linux-c -*- ------------------------------------------------------- *
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright 2007 rPath, Inc. - All Rights Reserved
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.
9 * ----------------------------------------------------------------------- */
12 * Very basic string functions
15 #include <linux/types.h>
20 * Undef these macros so that the functions that we provide
21 * here will have the correct names regardless of how string.h
22 * may have chosen to #define them.
28 int memcmp(const void *s1, const void *s2, size_t len)
31 asm("repe; cmpsb; setnz %0"
32 : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len));
36 int strcmp(const char *str1, const char *str2)
38 const unsigned char *s1 = (const unsigned char *)str1;
39 const unsigned char *s2 = (const unsigned char *)str2;
52 int strncmp(const char *cs, const char *ct, size_t count)
60 return c1 < c2 ? -1 : 1;
68 size_t strnlen(const char *s, size_t maxlen)
71 while (*es && maxlen) {
79 unsigned int atou(const char *s)
83 i = i * 10 + (*s++ - '0');
87 /* Works only for digits and letters, but small and fast */
88 #define TOLOWER(x) ((x) | 0x20)
90 static unsigned int simple_guess_base(const char *cp)
93 if (TOLOWER(cp[1]) == 'x' && isxdigit(cp[2]))
103 * simple_strtoull - convert a string to an unsigned long long
104 * @cp: The start of the string
105 * @endp: A pointer to the end of the parsed string will be placed here
106 * @base: The number base to use
109 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
111 unsigned long long result = 0;
114 base = simple_guess_base(cp);
116 if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x')
119 while (isxdigit(*cp)) {
122 value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10;
125 result = result * base + value;
134 long simple_strtol(const char *cp, char **endp, unsigned int base)
137 return -simple_strtoull(cp + 1, endp, base);
139 return simple_strtoull(cp, endp, base);
143 * strlen - Find the length of a string
144 * @s: The string to be sized
146 size_t strlen(const char *s)
150 for (sc = s; *sc != '\0'; ++sc)
156 * strstr - Find the first substring in a %NUL terminated string
157 * @s1: The string to be searched
158 * @s2: The string to search for
160 char *strstr(const char *s1, const char *s2)
170 if (!memcmp(s1, s2, l2))
178 * strchr - Find the first occurrence of the character c in the string s.
179 * @s: the string to be searched
180 * @c: the character to search for
182 char *strchr(const char *s, int c)
184 while (*s != (char)c)