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1// SPDX-License-Identifier: GPL-2.02/*3 * linux/tools/lib/string.c4 *5 * Copied from linux/lib/string.c, where it is:6 *7 * Copyright (C) 1991, 1992 Linus Torvalds8 *9 * More specifically, the first copied function was strtobool, which10 * was introduced by:11 *12 * d0f1fed29e6e ("Add a strtobool function matching semantics of existing in kernel equivalents")13 * Author: Jonathan Cameron <jic23@cam.ac.uk>14 */15 16#include <stdlib.h>17#include <string.h>18#include <errno.h>19#include <linux/string.h>20#include <linux/ctype.h>21#include <linux/compiler.h>22 23/**24 * memdup - duplicate region of memory25 *26 * @src: memory region to duplicate27 * @len: memory region length28 */29void *memdup(const void *src, size_t len)30{31 void *p = malloc(len);32 33 if (p)34 memcpy(p, src, len);35 36 return p;37}38 39/**40 * strtobool - convert common user inputs into boolean values41 * @s: input string42 * @res: result43 *44 * This routine returns 0 iff the first character is one of 'Yy1Nn0', or45 * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL. Value46 * pointed to by res is updated upon finding a match.47 */48int strtobool(const char *s, bool *res)49{50 if (!s)51 return -EINVAL;52 53 switch (s[0]) {54 case 'y':55 case 'Y':56 case '1':57 *res = true;58 return 0;59 case 'n':60 case 'N':61 case '0':62 *res = false;63 return 0;64 case 'o':65 case 'O':66 switch (s[1]) {67 case 'n':68 case 'N':69 *res = true;70 return 0;71 case 'f':72 case 'F':73 *res = false;74 return 0;75 default:76 break;77 }78 default:79 break;80 }81 82 return -EINVAL;83}84 85/**86 * strlcpy - Copy a C-string into a sized buffer87 * @dest: Where to copy the string to88 * @src: Where to copy the string from89 * @size: size of destination buffer90 *91 * Compatible with *BSD: the result is always a valid92 * NUL-terminated string that fits in the buffer (unless,93 * of course, the buffer size is zero). It does not pad94 * out the result like strncpy() does.95 *96 * If libc has strlcpy() then that version will override this97 * implementation:98 */99#ifdef __clang__100#pragma clang diagnostic push101#pragma clang diagnostic ignored "-Wignored-attributes"102#endif103size_t __weak strlcpy(char *dest, const char *src, size_t size)104{105 size_t ret = strlen(src);106 107 if (size) {108 size_t len = (ret >= size) ? size - 1 : ret;109 memcpy(dest, src, len);110 dest[len] = '\0';111 }112 return ret;113}114#ifdef __clang__115#pragma clang diagnostic pop116#endif117 118/**119 * skip_spaces - Removes leading whitespace from @str.120 * @str: The string to be stripped.121 *122 * Returns a pointer to the first non-whitespace character in @str.123 */124char *skip_spaces(const char *str)125{126 while (isspace(*str))127 ++str;128 return (char *)str;129}130 131/**132 * strim - Removes leading and trailing whitespace from @s.133 * @s: The string to be stripped.134 *135 * Note that the first trailing whitespace is replaced with a %NUL-terminator136 * in the given string @s. Returns a pointer to the first non-whitespace137 * character in @s.138 */139char *strim(char *s)140{141 size_t size;142 char *end;143 144 size = strlen(s);145 if (!size)146 return s;147 148 end = s + size - 1;149 while (end >= s && isspace(*end))150 end--;151 *(end + 1) = '\0';152 153 return skip_spaces(s);154}155 156/*157 * remove_spaces - Removes whitespaces from @s158 */159void remove_spaces(char *s)160{161 char *d = s;162 163 do {164 while (*d == ' ')165 ++d;166 } while ((*s++ = *d++));167}168 169/**170 * strreplace - Replace all occurrences of character in string.171 * @s: The string to operate on.172 * @old: The character being replaced.173 * @new: The character @old is replaced with.174 *175 * Returns pointer to the nul byte at the end of @s.176 */177char *strreplace(char *s, char old, char new)178{179 for (; *s; ++s)180 if (*s == old)181 *s = new;182 return s;183}184 185static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)186{187 while (bytes) {188 if (*start != value)189 return (void *)start;190 start++;191 bytes--;192 }193 return NULL;194}195 196/**197 * memchr_inv - Find an unmatching character in an area of memory.198 * @start: The memory area199 * @c: Find a character other than c200 * @bytes: The size of the area.201 *202 * returns the address of the first character other than @c, or %NULL203 * if the whole buffer contains just @c.204 */205void *memchr_inv(const void *start, int c, size_t bytes)206{207 u8 value = c;208 u64 value64;209 unsigned int words, prefix;210 211 if (bytes <= 16)212 return check_bytes8(start, value, bytes);213 214 value64 = value;215 value64 |= value64 << 8;216 value64 |= value64 << 16;217 value64 |= value64 << 32;218 219 prefix = (unsigned long)start % 8;220 if (prefix) {221 u8 *r;222 223 prefix = 8 - prefix;224 r = check_bytes8(start, value, prefix);225 if (r)226 return r;227 start += prefix;228 bytes -= prefix;229 }230 231 words = bytes / 8;232 233 while (words) {234 if (*(u64 *)start != value64)235 return check_bytes8(start, value, 8);236 start += 8;237 words--;238 }239 240 return check_bytes8(start, value, bytes % 8);241}242