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/ctype.h>
  10#include <linux/kernel.h>
  11#include <linux/types.h>
  12#include <linux/string.h>
  13
  14#ifndef __HAVE_ARCH_STRSTR
  15/**
  16 * strstr - Find the first substring in a %NUL terminated string
  17 * @s1: The string to be searched
  18 * @s2: The string to search for
  19 */
  20char *strstr(const char *s1, const char *s2)
  21{
  22        size_t l1, l2;
  23
  24        l2 = strlen(s2);
  25        if (!l2)
  26                return (char *)s1;
  27        l1 = strlen(s1);
  28        while (l1 >= l2) {
  29                l1--;
  30                if (!memcmp(s1, s2, l2))
  31                        return (char *)s1;
  32                s1++;
  33        }
  34        return NULL;
  35}
  36#endif
  37
  38#ifndef __HAVE_ARCH_STRNCMP
  39/**
  40 * strncmp - Compare two length-limited strings
  41 * @cs: One string
  42 * @ct: Another string
  43 * @count: The maximum number of bytes to compare
  44 */
  45int strncmp(const char *cs, const char *ct, size_t count)
  46{
  47        unsigned char c1, c2;
  48
  49        while (count) {
  50                c1 = *cs++;
  51                c2 = *ct++;
  52                if (c1 != c2)
  53                        return c1 < c2 ? -1 : 1;
  54                if (!c1)
  55                        break;
  56                count--;
  57        }
  58        return 0;
  59}
  60#endif
  61
  62/* Works only for digits and letters, but small and fast */
  63#define TOLOWER(x) ((x) | 0x20)
  64
  65static unsigned int simple_guess_base(const char *cp)
  66{
  67        if (cp[0] == '0') {
  68                if (TOLOWER(cp[1]) == 'x' && isxdigit(cp[2]))
  69                        return 16;
  70                else
  71                        return 8;
  72        } else {
  73                return 10;
  74        }
  75}
  76
  77/**
  78 * simple_strtoull - convert a string to an unsigned long long
  79 * @cp: The start of the string
  80 * @endp: A pointer to the end of the parsed string will be placed here
  81 * @base: The number base to use
  82 */
  83
  84unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
  85{
  86        unsigned long long result = 0;
  87
  88        if (!base)
  89                base = simple_guess_base(cp);
  90
  91        if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x')
  92                cp += 2;
  93
  94        while (isxdigit(*cp)) {
  95                unsigned int value;
  96
  97                value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10;
  98                if (value >= base)
  99                        break;
 100                result = result * base + value;
 101                cp++;
 102        }
 103        if (endp)
 104                *endp = (char *)cp;
 105
 106        return result;
 107}
 108
 109long simple_strtol(const char *cp, char **endp, unsigned int base)
 110{
 111        if (*cp == '-')
 112                return -simple_strtoull(cp + 1, endp, base);
 113
 114        return simple_strtoull(cp, endp, base);
 115}
 116