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 EFI_HAVE_STRLEN 15 /** 16 * strlen - Find the length of a string 17 * @s: The string to be sized 18 */ 19 size_t strlen(const char *s) 20 { 21 const char *sc; 22 23 for (sc = s; *sc != '\0'; ++sc) 24 /* nothing */; 25 return sc - s; 26 } 27 #endif 28 29 #ifndef EFI_HAVE_STRNLEN 30 /** 31 * strnlen - Find the length of a length-limited string 32 * @s: The string to be sized 33 * @count: The maximum number of bytes to search 34 */ 35 size_t strnlen(const char *s, size_t count) 36 { 37 const char *sc; 38 39 for (sc = s; count-- && *sc != '\0'; ++sc) 40 /* nothing */; 41 return sc - s; 42 } 43 #endif 44 45 /** 46 * strstr - Find the first substring in a %NUL terminated string 47 * @s1: The string to be searched 48 * @s2: The string to search for 49 */ 50 char *strstr(const char *s1, const char *s2) 51 { 52 size_t l1, l2; 53 54 l2 = strlen(s2); 55 if (!l2) 56 return (char *)s1; 57 l1 = strlen(s1); 58 while (l1 >= l2) { 59 l1--; 60 if (!memcmp(s1, s2, l2)) 61 return (char *)s1; 62 s1++; 63 } 64 return NULL; 65 } 66 67 #ifndef EFI_HAVE_STRCMP 68 /** 69 * strcmp - Compare two strings 70 * @cs: One string 71 * @ct: Another string 72 */ 73 int strcmp(const char *cs, const char *ct) 74 { 75 unsigned char c1, c2; 76 77 while (1) { 78 c1 = *cs++; 79 c2 = *ct++; 80 if (c1 != c2) 81 return c1 < c2 ? -1 : 1; 82 if (!c1) 83 break; 84 } 85 return 0; 86 } 87 #endif 88 89 /** 90 * strncmp - Compare two length-limited strings 91 * @cs: One string 92 * @ct: Another string 93 * @count: The maximum number of bytes to compare 94 */ 95 int strncmp(const char *cs, const char *ct, size_t count) 96 { 97 unsigned char c1, c2; 98 99 while (count) { 100 c1 = *cs++; 101 c2 = *ct++; 102 if (c1 != c2) 103 return c1 < c2 ? -1 : 1; 104 if (!c1) 105 break; 106 count--; 107 } 108 return 0; 109 } 110 111 /* Works only for digits and letters, but small and fast */ 112 #define TOLOWER(x) ((x) | 0x20) 113 114 static unsigned int simple_guess_base(const char *cp) 115 { 116 if (cp[0] == '0') { 117 if (TOLOWER(cp[1]) == 'x' && isxdigit(cp[2])) 118 return 16; 119 else 120 return 8; 121 } else { 122 return 10; 123 } 124 } 125 126 /** 127 * simple_strtoull - convert a string to an unsigned long long 128 * @cp: The start of the string 129 * @endp: A pointer to the end of the parsed string will be placed here 130 * @base: The number base to use 131 */ 132 133 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base) 134 { 135 unsigned long long result = 0; 136 137 if (!base) 138 base = simple_guess_base(cp); 139 140 if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x') 141 cp += 2; 142 143 while (isxdigit(*cp)) { 144 unsigned int value; 145 146 value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10; 147 if (value >= base) 148 break; 149 result = result * base + value; 150 cp++; 151 } 152 if (endp) 153 *endp = (char *)cp; 154 155 return result; 156 } 157 158 long simple_strtol(const char *cp, char **endp, unsigned int base) 159 { 160 if (*cp == '-') 161 return -simple_strtoull(cp + 1, endp, base); 162 163 return simple_strtoull(cp, endp, base); 164 } 165 166 #ifdef CONFIG_EFI_PARAMS_FROM_FDT 167 #ifndef EFI_HAVE_STRRCHR 168 /** 169 * strrchr - Find the last occurrence of a character in a string 170 * @s: The string to be searched 171 * @c: The character to search for 172 */ 173 char *strrchr(const char *s, int c) 174 { 175 const char *last = NULL; 176 do { 177 if (*s == (char)c) 178 last = s; 179 } while (*s++); 180 return (char *)last; 181 } 182 #endif 183 #ifndef EFI_HAVE_MEMCHR 184 /** 185 * memchr - Find a character in an area of memory. 186 * @s: The memory area 187 * @c: The byte to search for 188 * @n: The size of the area. 189 * 190 * returns the address of the first occurrence of @c, or %NULL 191 * if @c is not found 192 */ 193 void *memchr(const void *s, int c, size_t n) 194 { 195 const unsigned char *p = s; 196 while (n-- != 0) { 197 if ((unsigned char)c == *p++) { 198 return (void *)(p - 1); 199 } 200 } 201 return NULL; 202 } 203 #endif 204 #endif 205