/* Analagous to mp2dfr, but for whole-number radix 256 numbers rather
   than fractions.
   Kenneth B. Russell (kbrussel@media.mit.edu) 8/98 */

void
mp2d(unsigned char a[], unsigned char s[], int n, int *m)
{
  int j, k, c;
  unsigned char v;
  unsigned char t, carry;
  unsigned char msb;

  msb = ~0;
  msb = ~(msb >> 1);
  /* Round up digit estimate to avoid truncated output */
  *m = (int) (2.408 * n + 1);
  for (j=1;j<=(*m)+1;j++)
    s[j]=0;
  for (j=1;j<=n;j++) {
    v = a[j];
    for (k=0;k<8;k++) {
      /* Multiply s by 2 */
      carry=0;
      for (c=*m;c>=1;c--) {
	t=2*s[c]+carry;
	carry = t/10;
	s[c]=t%10;
      }
      if (v & msb) {
	/* Must add 1 to s */
	carry = 1;
	for (c=*m;c>=1;c--) {
	  t = s[c]+carry;
	  carry = t/10;
	  s[c]=t%10;
	}
      }
      v<<=1;
    }
  }
  for(j=1;j<=*m;j++)
    s[j]+='0';
  /* Trim leading zeros */
  j=1;
  while (s[j] == '0')
    j++;
  if (j>1) {
    for(k=j;k<=(*m)+1;k++)
      s[k-j+1]=s[k];
    *m=*m-j+1;
  }
}