// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) Paul Mackerras 1997.
 */
#include <linux/string.h>
#include <linux/stdarg.h>

size_t strnlen(const char * s, size_t count)
{
        const char *sc;

        for (sc = s; count-- && *sc != '\0'; ++sc)
                /* nothing */;
        return sc - s;
}

# define do_div(n, base) ({                                             \
        unsigned int __base = (base);                                   \
        unsigned int __rem;                                             \
        __rem = ((unsigned long long)(n)) % __base;                     \
        (n) = ((unsigned long long)(n)) / __base;                       \
        __rem;                                                          \
})


static int skip_atoi(const char **s)
{
        int i, c;

        for (i = 0; '0' <= (c = **s) && c <= '9'; ++*s)
                i = i*10 + c - '0';
        return i;
}

#define ZEROPAD 1               /* pad with zero */
#define SIGN    2               /* unsigned/signed long */
#define PLUS    4               /* show plus */
#define SPACE   8               /* space if plus */
#define LEFT    16              /* left justified */
#define SPECIAL 32              /* 0x */
#define LARGE   64              /* use 'ABCDEF' instead of 'abcdef' */

static char * number(char * str, unsigned long long num, int base, int size, int precision, int type)
{
        char c, sign, tmp[66];
        const char *digits = "0123456789abcdefghijklmnopqrstuvwxyz";
        int i;

        if (type & LARGE)
                digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        if (type & LEFT)
                type &= ~ZEROPAD;
        if (base < 2 || base > 36)
                return 0;
        c = (type & ZEROPAD) ? '0' : ' ';
        sign = 0;
        if (type & SIGN) {
                if ((signed long long)num < 0) {
                        sign = '-';
                        num = - (signed long long)num;
                        size--;
                } else if (type & PLUS) {
                        sign = '+';
                        size--;
                } else if (type & SPACE) {
                        sign = ' ';
                        size--;
                }
        }
        if (type & SPECIAL) {
                if (base == 16)
                        size -= 2;
                else if (base == 8)
                        size--;
        }
        i = 0;
        if (num == 0)
                tmp[i++]='0';
        else while (num != 0) {
                tmp[i++] = digits[do_div(num, base)];
        }
        if (i > precision)
                precision = i;
        size -= precision;
        if (!(type&(ZEROPAD+LEFT)))
                while (size-- > 0)
                        *str++ = ' ';
        if (sign)
                *str++ = sign;
        if (type & SPECIAL) {
                if (base==8)
                        *str++ = '0';
                else if (base == 16) {
                        *str++ = '0';
                        *str++ = digits[33];
                }
        }
        if (!(type & LEFT))
                while (size-- > 0)
                        *str++ = c;
        while (i < precision--)
                *str++ = '0';
        while (i-- > 0)
                *str++ = tmp[i];
        while (size-- > 0)
                *str++ = ' ';
        return str;
}

int vsprintf(char *buf, const char *fmt, va_list args)
{
        int len;
        unsigned long long num;
        int i, base;
        char * str;
        const char *s;

        int flags;              /* flags to number() */

        int field_width;        /* width of output field */
        int precision;          /* min. # of digits for integers; max
                                   number of chars for from string */
        int qualifier;          /* 'h', 'l', or 'L' for integer fields */
                                /* 'z' support added 23/7/1999 S.H.    */
                                /* 'z' changed to 'Z' --davidm 1/25/99 */


        for (str = buf ; *fmt ; ++fmt) {
                if (*fmt != '%') {
                        *str++ = *fmt;
                        continue;
                }

                /* process flags */
                flags = 0;
                repeat:
                        ++fmt;          /* this also skips first '%' */
                        switch (*fmt) {
                                case '-': flags |= LEFT; goto repeat;
                                case '+': flags |= PLUS; goto repeat;
                                case ' ': flags |= SPACE; goto repeat;
                                case '#': flags |= SPECIAL; goto repeat;
                                case '0': flags |= ZEROPAD; goto repeat;
                                }

                /* get field width */
                field_width = -1;
                if ('0' <= *fmt && *fmt <= '9')
                        field_width = skip_atoi(&fmt);
                else if (*fmt == '*') {
                        ++fmt;
                        /* it's the next argument */
                        field_width = va_arg(args, int);
                        if (field_width < 0) {
                                field_width = -field_width;
                                flags |= LEFT;
                        }
                }

                /* get the precision */
                precision = -1;
                if (*fmt == '.') {
                        ++fmt;
                        if ('0' <= *fmt && *fmt <= '9')
                                precision = skip_atoi(&fmt);
                        else if (*fmt == '*') {
                                ++fmt;
                                /* it's the next argument */
                                precision = va_arg(args, int);
                        }
                        if (precision < 0)
                                precision = 0;
                }

                /* get the conversion qualifier */
                qualifier = -1;
                if (*fmt == 'l' && *(fmt + 1) == 'l') {
                        qualifier = 'q';
                        fmt += 2;
                } else if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L'
                        || *fmt == 'Z') {
                        qualifier = *fmt;
                        ++fmt;
                }

                /* default base */
                base = 10;

                switch (*fmt) {
                case 'c':
                        if (!(flags & LEFT))
                                while (--field_width > 0)
                                        *str++ = ' ';
                        *str++ = (unsigned char) va_arg(args, int);
                        while (--field_width > 0)
                                *str++ = ' ';
                        continue;

                case 's':
                        s = va_arg(args, char *);
                        if (!s)
                                s = "<NULL>";

                        len = strnlen(s, precision);

                        if (!(flags & LEFT))
                                while (len < field_width--)
                                        *str++ = ' ';
                        for (i = 0; i < len; ++i)
                                *str++ = *s++;
                        while (len < field_width--)
                                *str++ = ' ';
                        continue;

                case 'p':
                        if (field_width == -1) {
                                field_width = 2*sizeof(void *);
                                flags |= ZEROPAD;
                        }
                        str = number(str,
                                (unsigned long) va_arg(args, void *), 16,
                                field_width, precision, flags);
                        continue;


                case 'n':
                        if (qualifier == 'l') {
                                long * ip = va_arg(args, long *);
                                *ip = (str - buf);
                        } else if (qualifier == 'Z') {
                                size_t * ip = va_arg(args, size_t *);
                                *ip = (str - buf);
                        } else {
                                int * ip = va_arg(args, int *);
                                *ip = (str - buf);
                        }
                        continue;

                case '%':
                        *str++ = '%';
                        continue;

                /* integer number formats - set up the flags and "break" */
                case 'o':
                        base = 8;
                        break;

                case 'X':
                        flags |= LARGE;
                case 'x':
                        base = 16;
                        break;

                case 'd':
                case 'i':
                        flags |= SIGN;
                case 'u':
                        break;

                default:
                        *str++ = '%';
                        if (*fmt)
                                *str++ = *fmt;
                        else
                                --fmt;
                        continue;
                }
                if (qualifier == 'l') {
                        num = va_arg(args, unsigned long);
                        if (flags & SIGN)
                                num = (signed long) num;
                } else if (qualifier == 'q') {
                        num = va_arg(args, unsigned long long);
                        if (flags & SIGN)
                                num = (signed long long) num;
                } else if (qualifier == 'Z') {
                        num = va_arg(args, size_t);
                } else if (qualifier == 'h') {
                        num = (unsigned short) va_arg(args, int);
                        if (flags & SIGN)
                                num = (signed short) num;
                } else {
                        num = va_arg(args, unsigned int);
                        if (flags & SIGN)
                                num = (signed int) num;
                }
                str = number(str, num, base, field_width, precision, flags);
        }
        *str = '\0';
        return str-buf;
}

int sprintf(char * buf, const char *fmt, ...)
{
        va_list args;
        int i;

        va_start(args, fmt);
        i = vsprintf(buf, fmt, args);
        va_end(args);
        return i;
}