OpenCloudOS-Kernel/tools/lib/string.c

229 lines
4.5 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* linux/tools/lib/string.c
*
* Copied from linux/lib/string.c, where it is:
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* More specifically, the first copied function was strtobool, which
* was introduced by:
*
* d0f1fed29e6e ("Add a strtobool function matching semantics of existing in kernel equivalents")
* Author: Jonathan Cameron <jic23@cam.ac.uk>
*/
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/compiler.h>
/**
* memdup - duplicate region of memory
*
* @src: memory region to duplicate
* @len: memory region length
*/
void *memdup(const void *src, size_t len)
{
void *p = malloc(len);
if (p)
memcpy(p, src, len);
return p;
}
/**
* strtobool - convert common user inputs into boolean values
* @s: input string
* @res: result
*
* This routine returns 0 iff the first character is one of 'Yy1Nn0', or
* [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL. Value
* pointed to by res is updated upon finding a match.
*/
int strtobool(const char *s, bool *res)
{
if (!s)
return -EINVAL;
switch (s[0]) {
case 'y':
case 'Y':
case '1':
*res = true;
return 0;
case 'n':
case 'N':
case '0':
*res = false;
return 0;
case 'o':
case 'O':
switch (s[1]) {
case 'n':
case 'N':
*res = true;
return 0;
case 'f':
case 'F':
*res = false;
return 0;
default:
break;
}
default:
break;
}
return -EINVAL;
}
/**
* strlcpy - Copy a C-string into a sized buffer
* @dest: Where to copy the string to
* @src: Where to copy the string from
* @size: size of destination buffer
*
* Compatible with *BSD: the result is always a valid
* NUL-terminated string that fits in the buffer (unless,
* of course, the buffer size is zero). It does not pad
* out the result like strncpy() does.
*
* If libc has strlcpy() then that version will override this
* implementation:
*/
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wignored-attributes"
#endif
size_t __weak strlcpy(char *dest, const char *src, size_t size)
{
size_t ret = strlen(src);
if (size) {
size_t len = (ret >= size) ? size - 1 : ret;
memcpy(dest, src, len);
dest[len] = '\0';
}
return ret;
}
#ifdef __clang__
#pragma clang diagnostic pop
#endif
/**
* skip_spaces - Removes leading whitespace from @str.
* @str: The string to be stripped.
*
* Returns a pointer to the first non-whitespace character in @str.
*/
char *skip_spaces(const char *str)
{
while (isspace(*str))
++str;
return (char *)str;
}
/**
* strim - Removes leading and trailing whitespace from @s.
* @s: The string to be stripped.
*
* Note that the first trailing whitespace is replaced with a %NUL-terminator
* in the given string @s. Returns a pointer to the first non-whitespace
* character in @s.
*/
char *strim(char *s)
{
size_t size;
char *end;
size = strlen(s);
if (!size)
return s;
end = s + size - 1;
while (end >= s && isspace(*end))
end--;
*(end + 1) = '\0';
return skip_spaces(s);
}
/**
* strreplace - Replace all occurrences of character in string.
* @s: The string to operate on.
* @old: The character being replaced.
* @new: The character @old is replaced with.
*
* Returns pointer to the nul byte at the end of @s.
*/
char *strreplace(char *s, char old, char new)
{
for (; *s; ++s)
if (*s == old)
*s = new;
return s;
}
static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)
{
while (bytes) {
if (*start != value)
return (void *)start;
start++;
bytes--;
}
return NULL;
}
/**
* memchr_inv - Find an unmatching character in an area of memory.
* @start: The memory area
* @c: Find a character other than c
* @bytes: The size of the area.
*
* returns the address of the first character other than @c, or %NULL
* if the whole buffer contains just @c.
*/
void *memchr_inv(const void *start, int c, size_t bytes)
{
u8 value = c;
u64 value64;
unsigned int words, prefix;
if (bytes <= 16)
return check_bytes8(start, value, bytes);
value64 = value;
value64 |= value64 << 8;
value64 |= value64 << 16;
value64 |= value64 << 32;
prefix = (unsigned long)start % 8;
if (prefix) {
u8 *r;
prefix = 8 - prefix;
r = check_bytes8(start, value, prefix);
if (r)
return r;
start += prefix;
bytes -= prefix;
}
words = bytes / 8;
while (words) {
if (*(u64 *)start != value64)
return check_bytes8(start, value, 8);
start += 8;
words--;
}
return check_bytes8(start, value, bytes % 8);
}