klib.c~

参照MINIX3写的操作系统 用GCC+NASM+BOCHS开发

#include "include/klib.h"
#include "include/string.h"
#include "include/stdarg.h"

int mystrlen(const char *str)
{
    int i;
 
    //assert(str != NULL);
    for (i = 0; str[i] != '\0'; i++);
    return i;
}

static char buf[1024];
PUBLIC char *itoa(char *str,int num)
{	char *p=str;
	char ch;
	int i;
	t_bool flag=FALSE;
	*p++='0';
	*p++='x';
	if(num==0)
		*p++='0';
	else
		for(i=28;i>=0;i-=4)
		{
			ch=(num>>i)&0xf;
			if(flag||(ch>0))
			{
				flag=TRUE;
				ch+='0';
				if(ch>'9')
				{
					ch+=7;
				}
				*p++=ch;
			}
		}
		*p=0;
		return str;
}

PUBLIC void DisplayInt(int Num)
{
	char OutPut[16];
	itoa(OutPut,Num);
	DisplayString(OutPut);

}


 void * memmove_kk(void * dest,const void *src,unsigned int count)
{
    char *tmp, *s;
/*如果目标地址小于源地址的话,从头开始拷贝*/
    if (dest <= src) {
        tmp = (char *) dest;
        s = (char *) src;
        while (count--)
            *tmp++ = *s++;
        }          
/*如果目标地址大于源地址的话,从尾部往前拷贝,这样就避免了当内存重叠时导致拷贝出错*/
    else {
        tmp = (char *) dest + count;
        s = (char *) src + count;
        while (count--)
            *--tmp = *--s;
        }

    return dest;
}




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

	while (is_digit(**s))
		i = i*10 + *((*s)++) - '0';
	return i;
}


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;
}

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=='\\')
			if(*(fmt+1)=='n'){
				*str++=(char)0xa;
				++fmt;
				++fmt;
				//continue;
			}
		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 *);
			len = mystrlen(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;
}




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

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

	DisplayString(buf);

	return i;
}

int printf(const char * fmt, ...)
{
	int i,j=0;
	int Len;
	va_list args;

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

	while(buf[j]!='\0') j++;
	sysWrite(buf,j,0);

	return i;
}

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

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

	DisplayString(buf);

	for(;;);

	return i;
}
extern Disp_pos;
void clear()
{
	Disp_pos=0;
	int i=0;
	for(i=0;i<25*80;i++)
		printk(" ");
	Disp_pos=0;

}


char * strcpy(char * strDest,const char * strSrc)
    {

                if ((strDest==NULL)||(strSrc==NULL)) //[1]

                        return NULL; //[2]

                char * strDestCopy=strDest;  //[3]

                while ((*strDest++=*strSrc++)!='\0'); //[4]

                return strDestCopy;

        }