// 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);
}