gmpfrxx.C

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/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
 
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
 
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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*/
 
 
// this file implements the routines required by gmpfrxx.h
// it is modeled on mpfr-2.2.1/out_str.c
//                   gmp-4.2.1/mpz/set_f.c
//                   gmp-4.2.1/mpq/set_f.c
 
// (written by Jon Wilkening on Aug 8, 2007)
 
 
#include "gmpfrxx.h"
 
using namespace std;
 
 
// MpFrC is a dummy class holding the static members of mpfr_class
mpfr_rnd_t  MpFrC::rnd = GMP_RNDN;
int         MpFrC::base = 10;
 
 
istream & operator>>(istream &s, mpfr_ptr a) {
    string tmp;
    s >> tmp;
    mpfr_set_str(a, tmp.c_str(),
     mpfr_class::get_base(),
     mpfr_class::get_rnd());
    // a = tmp.c_str();
    return s;
}
 
// modeled on mpfr-2.2.1/out_str.c
ostream & operator<<(ostream &os, mpfr_srcptr a)
{
    char *s, *t, *s0;
    mp_exp_t  e;
 
    // for debugging:
    // mpfr_out_str(stdout, 10, 0, a, RND); printf("\n");
 
    if (mpfr_nan_p(a)) {
  os << "@NaN@";
  return os;
    }
 
    if (mpfr_inf_p(a)) {
  if (MPFR_SIGN(a) > 0)
      os << "@Inf@";
  else
      os << "-@Inf@";
  return os;
    }
 
    if (mpfr_zero_p(a)) {
  if (MPFR_SIGN(a) > 0)
      os << "0";
  else
      os << "-0";
  return os;
    }
 
    s = mpfr_get_str (nullptr, &e,
          mpfr_class::get_base(),
          0, a,
          mpfr_class::get_rnd());
 
    t = mpfr_get_str (nullptr, &e,
          mpfr_class::get_base(),
          os.precision(), a,
          mpfr_class::get_rnd());
 
    if (strlen(s)<strlen(t))
  mpfr_free_str(t);
    else {
  mpfr_free_str(s);
  s = t;
    }
 
    s0 = s;
    /* for a=3.1416 we have s = "31416" and e = 1 */
 
    if (*s == '-')
  os.put(*s++);
 
    /* outputs mantissa */
    os.put(*s++); e--; /* leading digit */
    os.put('.');
    while (*s != '\0')
  os.put(*s++);       /* rest of mantissa */
 
    mpfr_free_str(s0);
 
    /* outputs exponent */
    if (e) {
  os << (mpfr_class::get_base() <= 10 ? 'e' : '@') << (long) e;
    }
 
    return os;
}
 
// fixme: it would be more efficient to work directly
// with the limbs, but I don't want to deal with the
// internal representations of both mpfr and gmp
void mpz_set_mpfr(mpz_ptr w, mpfr_srcptr u)
{
    char *s, *t;
    long k, sz;
    mp_exp_t  e;
  
    // abs(u)<1 truncates to zero
    if ( mpfr_get_exp(u)<=0 || mpfr_zero_p(u)
   || mpfr_nan_p(u) || mpfr_inf_p(u) ) {
  mpz_set_ui(w, 0);
  return;
    }
 
    // note: this is done in hex to represent u exactly
    // example: for u=3.1416 we have s = "31416" and e = 1
    s = mpfr_get_str (nullptr, &e, 16, 0, u, GMP_RNDN);
    sz = strlen(s);
 
    if (*s == '-')
  e++;
 
    if (e<=sz) {
  s[e] = '\0'; // truncate
  mpz_set_str(w, s, 16);
  mpfr_free_str(s);
  return;
    }
 
    t = (char *) calloc(e+1, sizeof(char));
    
    for (k=0; k<sz; k++)
  t[k] = s[k];
    for (k=sz; k<e; k++)
  t[k] = '0';
    t[e] = '\0';
 
    mpz_set_str(w, t, 16);
    free(t);
    mpfr_free_str(s);
}
 
 
void mpq_set_mpfr(mpq_ptr w, mpfr_srcptr u)
{
    char *s, *t;
    long k, sz;
    mp_exp_t  e, bits;
    
    if ( mpfr_zero_p(u) || mpfr_nan_p(u) || mpfr_inf_p(u) ) {
  mpq_set_ui(w, 0, 1);
  return;
    }
 
    // note: this is done in binary to represent u exactly
    // example:   u=10.1001  -->  s = "101001", e = 2
    s = mpfr_get_str (nullptr, &e, 2, 0, u, GMP_RNDN);
    sz = strlen(s);
 
    t = s+sz;
    while (*(--t) == '0')
  *t = '\0'; // trim trailing zeros
 
    sz = strlen(s);
    bits = (*s == '-') ? sz-1 : sz; // bits>0 since u!=0
 
    if (e>=bits) {
  e = sz+e-bits;
  // no denominator needed
  t = (char *) malloc((e+1)*sizeof(char));
  strcpy(t,s);
  for (k=sz; k<e; k++)
      t[k] = '0';
  t[e] = '\0';
  mpq_set_str(w, t, 2);
  free(t);
  mpfr_free_str(s);
  return;
    }
 
    e = sz+bits-e+2;
    t = (char *) malloc((e+1)*sizeof(char));
    strcpy(t,s);
    t[sz++] = '/';
    t[sz++] = '1';
    for (k=sz; k<e; k++)
  t[k] = '0';
    t[e] = '\0';
    mpq_set_str(w, t, 2);
    free(t);
    mpfr_free_str(s);
}