LXR linux/drivers/firmware/efi/libstub/string.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Taken from:
   4 *  linux/lib/string.c
   5 *
   6 *  Copyright (C) 1991, 1992  Linus Torvalds
   7 */
   8
   9#include <linux/types.h>
  10#include <linux/string.h>
  11
  12#ifndef __HAVE_ARCH_STRSTR
  13/**
  14 * strstr - Find the first substring in a %NUL terminated string
  15 * @s1: The string to be searched
  16 * @s2: The string to search for
  17 */
  18char *strstr(const char *s1, const char *s2)
  19{
  20        size_t l1, l2;
  21
  22        l2 = strlen(s2);
  23        if (!l2)
  24                return (char *)s1;
  25        l1 = strlen(s1);
  26        while (l1 >= l2) {
  27                l1--;
  28                if (!memcmp(s1, s2, l2))
  29                        return (char *)s1;
  30                s1++;
  31        }
  32        return NULL;
  33}
  34#endif
  35
  36#ifndef __HAVE_ARCH_STRNCMP
  37/**
  38 * strncmp - Compare two length-limited strings
  39 * @cs: One string
  40 * @ct: Another string
  41 * @count: The maximum number of bytes to compare
  42 */
  43int strncmp(const char *cs, const char *ct, size_t count)
  44{
  45        unsigned char c1, c2;
  46
  47        while (count) {
  48                c1 = *cs++;
  49                c2 = *ct++;
  50                if (c1 != c2)
  51                        return c1 < c2 ? -1 : 1;
  52                if (!c1)
  53                        break;
  54                count--;
  55        }
  56        return 0;
  57}
  58#endif
  59