/*
 ****************************************************************************
 * (C) 2003 - Rolf Neugebauer - Intel Research Cambridge
 ****************************************************************************
 *
 *        File: printf.c
 *      Author: Rolf Neugebauer (neugebar@dcs.gla.ac.uk)
 *     Changes: Grzegorz Milos (gm281@cam.ac.uk)
 *
 *        Date: Aug 2003, Aug 2005
 *
 * Environment: Xen Minimal OS
 * Description: Library functions for printing
 *              (freebsd port, mainly sys/subr_prf.c)
 *
 ****************************************************************************
 *
 *-
 * Copyright (c) 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This software was developed by the Computer Systems Engineering group
 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
 * contributed to Berkeley.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: src/sys/libkern/divdi3.c,v 1.6 1999/08/28 00:46:31 peter Exp $
 */

#include "ctype.h"
#include "stdarg.h"
#include "stdio.h"
#include "string.h"

static int skip_atoi(const char **s)
{
    int i = 0;

    while (isdigit(**s))
        i = i * 10 + *((*s)++) - '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 *buf, char *end, long long num, int base, int size,
                    int precision, int type)
{
    char c, sign, tmp[66];
    const char *digits;
    const char small_digits[] = "0123456789abcdefghijklmnopqrstuvwxyz";
    const char large_digits[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    int i;

    digits = (type & LARGE) ? large_digits : small_digits;
    if (type & LEFT)
    {
        type &= ~ZEROPAD;
    }
    if (base < 2 || base > 36)
    {
        return buf;
    }
    c = (type & ZEROPAD) ? '0' : ' ';
    sign = 0;
    if (type & SIGN)
    {
        if (num < 0)
        {
            sign = '-';
            num = -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
    {
        /* XXX KAF: force unsigned mod and div. */
        /* XXX kernel does not support long long division */
        unsigned long long num2 = (unsigned long long)num;
        unsigned int base2 = (unsigned int)base;
        while (num2 != 0)
        {
            tmp[i++] = digits[num2 % base2];
            num2 /= base2;
        }
    }
    if (i > precision)
    {
        precision = i;
    }
    size -= precision;
    if (!(type & (ZEROPAD + LEFT)))
    {
        while (size-- > 0)
        {
            if (buf <= end)
            {
                *buf = ' ';
            }
            ++buf;
        }
    }
    if (sign)
    {
        if (buf <= end)
        {
            *buf = sign;
        }
        ++buf;
    }
    if (type & SPECIAL)
    {
        if (base == 8)
        {
            if (buf <= end)
            {
                *buf = '0';
            }
            ++buf;
        }
        else if (base == 16)
        {
            if (buf <= end)
            {
                *buf = '0';
            }
            ++buf;
            if (buf <= end)
            {
                *buf = digits[33];
            }
            ++buf;
        }
    }
    if (!(type & LEFT))
    {
        while (size-- > 0)
        {
            if (buf <= end)
            {
                *buf = c;
            }
            ++buf;
        }
    }
    while (i < precision--)
    {
        if (buf <= end)
        {
            *buf = '0';
        }
        ++buf;
    }
    while (i-- > 0)
    {
        if (buf <= end)
        {
            *buf = tmp[i];
        }
        ++buf;
    }
    while (size-- > 0)
    {
        if (buf <= end)
        {
            *buf = ' ';
        }
        ++buf;
    }
    return buf;
}

/* TODO This is a copy of the kernel vsnprintf. It has (almost)
 * no error checking. It also is completely unable to handle
 * floating point. - alvin */
/**
 * vsnprintf - Format a string and place it in a buffer
 * @buf: The buffer to place the result into
 * @size: The size of the buffer, including the trailing null space
 * @fmt: The format string to use
 * @args: Arguments for the format string
 *
 * Call this function if you are already dealing with a va_list.
 * You probably want snprintf instead.
 */
int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
{
    int len;
    unsigned long long num;
    int i, base;
    char *str, *end, c;
    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 */

    str = buf;
    end = buf + size - 1;

    if (end < buf - 1)
    {
        end = ((void *)-1);
        size = end - buf + 1;
    }

    for (; *fmt; ++fmt)
    {
        if (*fmt != '%')
        {
            if (str <= end)
            {
                *str = *fmt;
            }
            ++str;
            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 (isdigit(*fmt))
        {
            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 (isdigit(*fmt))
            {
                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 == 'h' || *fmt == 'l' || *fmt == 'L' || *fmt == 'Z')
        {
            qualifier = *fmt;
            ++fmt;
            if (qualifier == 'l' && *fmt == 'l')
            {
                qualifier = 'L';
                ++fmt;
            }
        }
        if (*fmt == 'q')
        {
            qualifier = 'L';
            ++fmt;
        }

        /* default base */
        base = 10;

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

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

            len = strnlen(s, precision);

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

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

        case 'n':
            /* FIXME:
                 * What does C99 say about the overflow case here? */
            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 '%':
            if (str <= end)
            {
                *str = '%';
            }
            ++str;
            continue;

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

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

        case 'd':
        case 'i':
            flags |= SIGN;
        case 'u':
            break;
            /* Added - TODO - alvin */
        case 'f':
        case 'F':
        case 'g':
        case 'G':
            return -1;

        default:
            if (str <= end)
            {
                *str = '%';
            }
            ++str;
            if (*fmt)
            {
                if (str <= end)
                {
                    *str = *fmt;
                }
                ++str;
            }
            else
            {
                --fmt;
            }
            continue;
        }
        if (qualifier == 'L')
        {
            num = va_arg(args, long long);
        }
        else if (qualifier == 'l')
        {
            num = va_arg(args, unsigned long);
            if (flags & SIGN)
            {
                num = (signed 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, end, num, base, field_width, precision, flags);
    }
    if (str <= end)
    {
        *str = '\0';
    }
    else if (size > 0)
    {
        /* don't write out a null byte if the buf size is zero */
        *end = '\0';
    }
    /* the trailing null byte doesn't count towards the total
     * ++str;
     */
    return str - buf;
}