arch/x86/boot/string.c

   1 /* -*- linux-c -*- ------------------------------------------------------- *
   2  *
   3  *   Copyright (C) 1991, 1992 Linus Torvalds
   4  *   Copyright 2007 rPath, Inc. - All Rights Reserved
   5  *
   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.
   8  *
   9  * ----------------------------------------------------------------------- */
  10
  11 /*
  12  * arch/i386/boot/string.c
  13  *
  14  * Very basic string functions
  15  */
  16
  17 #include "boot.h"
  18
  19 int strcmp(const char *str1, const char *str2)
  20 {
  21         const unsigned char *s1 = (const unsigned char *)str1;
  22         const unsigned char *s2 = (const unsigned char *)str2;
  23         int delta = 0;
  24
  25         while (*s1 || *s2) {
  26                 delta = *s2 - *s1;
  27                 if (delta)
  28                         return delta;
  29                 s1++;
  30                 s2++;
  31         }
  32         return 0;
  33 }
  34
  35 size_t strnlen(const char *s, size_t maxlen)
  36 {
  37         const char *es = s;
  38         while (*es && maxlen) {
  39                 es++;
  40                 maxlen--;
  41         }
  42
  43         return (es - s);
  44 }
  45
  46 unsigned int atou(const char *s)
  47 {
  48         unsigned int i = 0;
  49         while (isdigit(*s))
  50                 i = i * 10 + (*s++ - '0');
  51         return i;
  52 }