vsprintf.c

SimpleGraphicOperatingSystem 32位图形化操作系统 多进程 支持FAT32 详见www.sgos.net.cn

#include <Osdef.h>

/*
 * 该文件来自Linux1.0代码
 * 保留Linus Torvalds的版权
 */
 
/*
 *  linux/kernel/vsprintf.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

/* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */
/*
 * Wirzenius wrote this portably, Torvalds fucked it up :-)
 */

#include <stdarg.h>
#include <TYPE.h>
#include <string.h>
#include <ctype.h>

unsigned long simple_strtoul(const char *cp,char **endp,unsigned int base)
{
    unsigned long result = 0,value;

    if (!base) {
        base = 10;
        if (*cp == '0') {
            base = 8;
        	cp++;
            if ((*cp == 'x') && isxdigit(cp[1])) {
            	cp++;
                base = 16;
    		}
    	}
    }
    while (isxdigit(*cp) && (value = isdigit(*cp) ? *cp-'0' : (islower(*cp)
        ? toupper(*cp) : *cp)-'A'+10) < base) {
        result = result*base + value;
        cp++;
    }
    if (endp)
        *endp = (char *)cp;
    return result;
}

/* we use this so that we can do without the ctype library */
#define is_digit(c) ((c) >= '0' && (c) <= '9')

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

    while (is_digit(**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 SMALL   64      /* use 'abcdef' instead of 'ABCDEF' */

#define do_div(n,base) ({ \
int __res; \
__asm__("divl %4":"=a" (n),"=d" (__res):"0" (n),"1" (0),"r" (base)); \
__res; })

static char * number(char * str, int num, int base, int size, int precision
    ,int type)
{
    char c,sign,tmp[36];
    const char *digits="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    int i;

    if (type&SMALL) digits="0123456789abcdefghijklmnopqrstuvwxyz";
    if (type&LEFT) type &= ~ZEROPAD;
    if (base<2 || base>36)
        return 0;
    c = (type & ZEROPAD) ? '0' : ' ' ;
    if (type&SIGN && num<0) {
        sign='-';
        num = -num;
    } else
        sign=(type&PLUS) ? '+' : ((type&SPACE) ? ' ' : 0);
    if (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;
}

EXPORT int vsprintf(char *buf, const char *fmt, va_list args)
{
    int len;
    int i;
    char * str;
    char *s;
    int *ip;

    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 */

    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 (is_digit(*fmt))
            field_width = skip_atoi(&fmt);
        else if (*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 (is_digit(*fmt))
                precision = skip_atoi(&fmt);
            else if (*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') {
            qualifier = *fmt;
            ++fmt;
    	}

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

        case 's':
            s = va_arg(args, char *);
            if (!s)
                s = "<NULL>";
            len = strlen(s);
            if (precision < 0)
                precision = len;
            else if (len > precision)
                len = precision;

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

        case 'o':
            str = number(str, va_arg(args, unsigned long), 8,
                field_width, precision, flags);
            break;

        case 'p':
            if (field_width == -1) {
                field_width = 8;
                flags |= ZEROPAD;
    		}
            str = number(str,
                (unsigned long) va_arg(args, void *), 16,
                field_width, precision, flags);
            break;

        case 'x':
            flags |= SMALL;
        case 'X':
            str = number(str, va_arg(args, unsigned long), 16,
                field_width, precision, flags);
            break;

        case 'd':
        case 'i':
            flags |= SIGN;
        case 'u':
            str = number(str, va_arg(args, unsigned long), 10,
                field_width, precision, flags);
            break;

        case 'n':
            ip = va_arg(args, int *);
            *ip = (str - buf);
            break;

        default:
            if (*fmt != '%')
                *str++ = '%';
            if (*fmt)
                *str++ = *fmt;
        	else
            	--fmt;
            break;
    	}
    }
    *str = '\0';
    return str-buf;
}

EXPORT 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;
}