/* mpfr_set_str_raw -- set a floating-point number from a binary string

Copyright 1999, 2000, 2001 Free Software Foundation, Inc.

This file is part of the MPFR Library.

The MPFR Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version.

The MPFR Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the MPFR Library; see the file COPYING.LIB.  If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "gmp.h"
#include "gmp-impl.h"
#include "longlong.h"
#include "mpfr.h"
#include "mpfr-impl.h"

/* Currently the number should be of the form +/- xxxx.xxxxxxEyy, with 
   decimal exponent. The mantissa of x is supposed to be large enough 
   to hold all the bits of str. */

void
mpfr_set_str_raw (mpfr_ptr x, char *str)
{
  char *str2, *str0, negative = 0; 
  unsigned long j, l, k = 0, xsize, cnt, alloc; mp_limb_t *xp; 
  long expn = 0, e; char *endstr2;

  xp = MPFR_MANT(x);
  xsize = 1 + (MPFR_PREC(x) - 1) / BITS_PER_MP_LIMB;
  alloc = (strlen(str) + 1) * sizeof(char);

  if (*str == '-')
    {
      negative = 1;
      str++;
    }
  else if (*str == '+')
    str++;
  
  if (*str == 'N')
    {
      MPFR_SET_NAN(x);
      __mpfr_flags |= MPFR_FLAGS_NAN;
      return;
    }

  if (*str == 'I') 
    { 
      MPFR_CLEAR_NAN(x);
      MPFR_SET_INF(x);
      if (MPFR_ISNEG(x) != negative)
	MPFR_CHANGE_SIGN(x);
      return; 
    }
     
  MPFR_CLEAR_FLAGS(x);
 
  str0 = str2 = (char *) (*__gmp_allocate_func) (alloc);

  while (*str == '0') { str++; } 

  while (*str == '0' || *str == '1')
    { *(str2++) = *(str++); k++; }

  if (*str == '.') 
    {
      str++;
      while (*str == '0' || *str == '1')
	{ *(str2++) = *(str++); }

      if (*str == '[') { while (*str != ']') str++; }
    }
    
  if (*str == '[') { while (*str != ']') str++; }

  if (*str == 'e' || *str == 'E') 
    {
      e = atol(++str); /* signed exponent after 'e' or 'E' */
      expn = k + e; 
      if (expn < e)
	  fprintf(stderr, "Warning: overflow in exponent in Str -> mpfr\n"); 
    }
  else expn=k;

  endstr2 = str2;
  l = endstr2 - str0; /* length of mantissa */
  if (l == 0) { /* input is zero */
    MPFR_SET_ZERO(x);
  }
  else {
    l = (l - 1) / BITS_PER_MP_LIMB + 1;
    str2 = str0;

    if (l > xsize) {
      fprintf (stderr, "Error: mantissa larger than precision of destination variable in mpfr_set_str_raw\n");
      exit (1);
    }

    /* str2[0]..endstr2[-1] contains the mantissa */
    for (k = 1; k <= l; k++)
      {
	j = 0; 
	xp[xsize - k] = 0; 
	while ((str2 < endstr2) && (j < BITS_PER_MP_LIMB))
	  {
	    xp[xsize - k] = (xp[xsize - k] << 1) + (*str2 - '0'); 
	    str2++; j++; 
	  }
	xp[xsize - k] <<= (BITS_PER_MP_LIMB - j); 
      }

    for (; k <= xsize; k++) { xp[xsize - k] = 0; }

    count_leading_zeros(cnt, xp[xsize - 1]); 
    if (cnt) mpn_lshift(xp, xp, xsize, cnt); 

    MPFR_EXP(x) = expn - cnt; 
    if (MPFR_ISNEG(x) != negative)
      MPFR_CHANGE_SIGN(x);
  }

  (*__gmp_free_func) (str0, alloc);
  
  /* May change to take into account : syntax errors, overflow in exponent, 
     string truncated because of size of x */
}