diff options
Diffstat (limited to 'kernel/arch/x86/boot/string.c')
-rw-r--r-- | kernel/arch/x86/boot/string.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/kernel/arch/x86/boot/string.c b/kernel/arch/x86/boot/string.c new file mode 100644 index 000000000..318b8465d --- /dev/null +++ b/kernel/arch/x86/boot/string.c @@ -0,0 +1,157 @@ +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007 rPath, Inc. - All Rights Reserved + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2. + * + * ----------------------------------------------------------------------- */ + +/* + * Very basic string functions + */ + +#include <linux/types.h> +#include "ctype.h" + +int memcmp(const void *s1, const void *s2, size_t len) +{ + u8 diff; + asm("repe; cmpsb; setnz %0" + : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len)); + return diff; +} + +int strcmp(const char *str1, const char *str2) +{ + const unsigned char *s1 = (const unsigned char *)str1; + const unsigned char *s2 = (const unsigned char *)str2; + int delta = 0; + + while (*s1 || *s2) { + delta = *s1 - *s2; + if (delta) + return delta; + s1++; + s2++; + } + return 0; +} + +int strncmp(const char *cs, const char *ct, size_t count) +{ + unsigned char c1, c2; + + while (count) { + c1 = *cs++; + c2 = *ct++; + if (c1 != c2) + return c1 < c2 ? -1 : 1; + if (!c1) + break; + count--; + } + return 0; +} + +size_t strnlen(const char *s, size_t maxlen) +{ + const char *es = s; + while (*es && maxlen) { + es++; + maxlen--; + } + + return (es - s); +} + +unsigned int atou(const char *s) +{ + unsigned int i = 0; + while (isdigit(*s)) + i = i * 10 + (*s++ - '0'); + return i; +} + +/* Works only for digits and letters, but small and fast */ +#define TOLOWER(x) ((x) | 0x20) + +static unsigned int simple_guess_base(const char *cp) +{ + if (cp[0] == '0') { + if (TOLOWER(cp[1]) == 'x' && isxdigit(cp[2])) + return 16; + else + return 8; + } else { + return 10; + } +} + +/** + * simple_strtoull - convert a string to an unsigned long long + * @cp: The start of the string + * @endp: A pointer to the end of the parsed string will be placed here + * @base: The number base to use + */ + +unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base) +{ + unsigned long long result = 0; + + if (!base) + base = simple_guess_base(cp); + + if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x') + cp += 2; + + while (isxdigit(*cp)) { + unsigned int value; + + value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10; + if (value >= base) + break; + result = result * base + value; + cp++; + } + if (endp) + *endp = (char *)cp; + + return result; +} + +/** + * strlen - Find the length of a string + * @s: The string to be sized + */ +size_t strlen(const char *s) +{ + const char *sc; + + for (sc = s; *sc != '\0'; ++sc) + /* nothing */; + return sc - s; +} + +/** + * strstr - Find the first substring in a %NUL terminated string + * @s1: The string to be searched + * @s2: The string to search for + */ +char *strstr(const char *s1, const char *s2) +{ + size_t l1, l2; + + l2 = strlen(s2); + if (!l2) + return (char *)s1; + l1 = strlen(s1); + while (l1 >= l2) { + l1--; + if (!memcmp(s1, s2, l2)) + return (char *)s1; + s1++; + } + return NULL; +} |