多倍長演算ライブラリ ルーチン３０

/*		lread.c		*/
#include "longint.h"

/* setting LINT by string */

LINT lread(char *s)
{
	LINT a;
	int c[MAXLEN2], *pc;
	char *ps;
	int i, j, k, n;

	i = 0;
	while(++i <= MAXLEN)	a.num[i] = 0;
	if(strlen(s) < 5)
	{
		i = atoi(s);
		a.sign = (i >= 0)? 0: -1;
		if(i == 0)	a.len = 0;
		else
		{
			a.len = 1;
			a.num[1] = (a.sign == 0)? i: -i;
		}
		return a;
	}

	ps = s;
	n = 0;
	pc = c;
	a.sign = 0;
	while(*ps && n < MAXLEN2)
	{
		*pc++ = *ps++ - '0';
		n++;
	}

	j = 0;
	a.len = i = --n / 4 + 1;
	if(n % 4 != 3)
	{
		a.num[i] = 0;
		do
		{
			a.num[i] *= 10;
			a.num[i] += c[j++];
		} while(--n % 4 != 3);
		i--;
	}
	while(i >= 0)
	{
		a.num[i] = c[j++];
		for(k = 0; k < 3; k++)
		{
			a.num[i] *= 10;
			a.num[i] += c[j++];
		}
		i--;
	}
	return a;
}