text: /****************************************************************************
   * Core Library Version 1.7, August 2004
   * Copyright (c) 1995-2004 Exact Computation Project
   * All rights reserved.
   *
   * file: GmpIO.cpp
   * 		Adapted from multi-files under /cxx in GMP's source distribution
   *
   * Zilin Du, 2003
   *
   * $URL: https://github.com/CGAL/cgal/blob/releases/CGAL-5.0.2/CGAL_Core/include/CGAL/CORE/Gmp_impl.h $
   * $Id: Gmp_impl.h 26fb266 2019-10-19T16:28:33+02:00 Sébastien Loriot
   * SPDX-License-Identifier: LGPL-3.0-only
   ***************************************************************************/
  
  /* Auxiliary functions for C++-style input of GMP types. 
  
  Copyright 2001 Free Software Foundation, Inc.
  
  This file is part of the GNU MP Library.
  
  */
  
  #ifdef CGAL_HEADER_ONLY
  #define CGAL_INLINE_FUNCTION inline
  #else
  #define CGAL_INLINE_FUNCTION
  #endif
  
  #include <CGAL/CORE/Gmp.h>
  #include <cctype>
  #include <iostream>
  #include <string>
  #include <cstdio>
  
  namespace CORE { 
  
  CGAL_INLINE_FUNCTION
  int
  __gmp_istream_set_base (std::istream &i, char &c, bool &zero, bool &showbase)
  {
    int base;
    using std::ios;
  
    zero = showbase = false;
    switch (i.flags() & ios::basefield)
      {
      case ios::dec:
        base = 10;
        break;
      case ios::hex:
        base = 16;
        break;
      case ios::oct:
        base = 8;
        break;
      default:
        showbase = true; // look for initial "0" or "0x" or "0X"
        if (c == '0')
  	{
  	  if (! i.get(c))
  	    c = 0; // reset or we might loop indefinitely
  
  	  if (c == 'x' || c == 'X')
  	    {
  	      base = 16;
  	      i.get(c);
  	    }
  	  else
  	    {
  	      base = 8;
  	      zero = true; // if no other digit is read, the "0" counts
  	    }
  	}
        else
  	base = 10;
        break;
      }
  
    return base;
  }
  
  CGAL_INLINE_FUNCTION
  void
  __gmp_istream_set_digits (std::string &s, std::istream &i, char &c, bool &ok, int base)
  {
    switch (base)
      {
      case 10:
        while (isdigit(c))
  	{
  	  ok = true; // at least a valid digit was read
  	  s += c;
  	  if (! i.get(c))
  	    break;
  	}
        break;
      case 8:
        while (isdigit(c) && c != '8' && c != '9')
  	{
  	  ok = true; // at least a valid digit was read
  	  s += c;
  	  if (! i.get(c))
  	    break;
  	}
        break;
      case 16:
        while (isxdigit(c))
  	{
  	  ok = true; // at least a valid digit was read
  	  s += c;
  	  if (! i.get(c))
  	    break;
  	}
        break;
      }
  }
  
  CGAL_INLINE_FUNCTION
  std::istream &
  //operator>> (std::istream &i, mpz_ptr z)
  io_read (std::istream &i, mpz_ptr z)
  {
    using namespace std;
    int base;
    char c = 0;
    std::string s;
    bool ok = false, zero, showbase;
  
    i.get(c); // start reading
  
    if (i.flags() & ios::skipws) // skip initial whitespace
      while (isspace(c) && i.get(c))
        ;
  
    if (c == '-' || c == '+') // sign
      {
        if (c == '-') // mpz_set_str doesn't accept '+'
  	s = "-";
        i.get(c);
      }
  
    while (isspace(c) && i.get(c)) // skip whitespace
      ;
  
    base = __gmp_istream_set_base(i, c, zero, showbase); // select the base
    __gmp_istream_set_digits(s, i, c, ok, base);         // read the number
  
    if (i.good()) // last character read was non-numeric
      i.putback(c);
    else if (i.eof() && (ok || zero)) // stopped just before eof
      i.clear();
  
    if (ok)
      mpz_set_str(z, s.c_str(), base); // extract the number
    else if (zero)
      mpz_set_ui(z, 0);
    else
      i.setstate(ios::failbit); // read failed
  
    return i;
  }
  
  CGAL_INLINE_FUNCTION
  std::istream &
  //operator>> (std::istream &i, mpq_ptr q)
  io_read (std::istream &i, mpq_ptr q)
  {
    using namespace std;
    int base;
    char c = 0;
    std::string s;
    bool ok = false, zero, showbase;
  
    i.get(c); // start reading
  
    if (i.flags() & ios::skipws) // skip initial whitespace
      while (isspace(c) && i.get(c))
        ;
  
    if (c == '-' || c == '+') // sign
      {
        if (c == '-')
  	s = "-";
        i.get(c);
      }
  
    while (isspace(c) && i.get(c)) // skip whitespace
      ;
  
    base = __gmp_istream_set_base(i, c, zero, showbase); // select the base
    __gmp_istream_set_digits(s, i, c, ok, base);         // read the numerator
  
    if (! ok && zero) // the only digit read was "0"
      {
        base = 10;
        s += '0';
        ok = true;
      }
  
    if (i.flags() & ios::skipws)
      while (isspace(c) && i.get(c)) // skip whitespace
        ;
  
    if (c == '/') // there's a denominator
      {
        bool zero2 = false;
        int base2 = base;
  
        s += '/';
        ok = false; // denominator is mandatory
        i.get(c);
  
        while (isspace(c) && i.get(c)) // skip whitespace
  	;
  
        if (showbase) // check base of denominator
  	base2 = __gmp_istream_set_base(i, c, zero2, showbase);
  
        if (base2 == base || base2 == 10) // read the denominator
  	__gmp_istream_set_digits(s, i, c, ok, base);
  
        if (! ok && zero2) // the only digit read was "0"
  	{                // denominator is 0, but that's your business
  	  s += '0';
  	  ok = true;
  	}
      }
  
    if (i.good()) // last character read was non-numeric
      i.putback(c);
    else if (i.eof() && ok) // stopped just before eof
      i.clear();
  
    if (ok)
      mpq_set_str(q, s.c_str(), base); // extract the number
    else
      i.setstate(ios::failbit); // read failed
  
    return i;
  }
  
  CGAL_INLINE_FUNCTION
  std::ostream&
  //operator<< (std::ostream &o, mpz_srcptr z)
  io_write (std::ostream &o, mpz_srcptr z)
  { 
    char *str = new char [mpz_sizeinbase(z,10) + 2];
    str = mpz_get_str(str, 10, z);
    o << str ;
    delete[] str;
    return o; 
  }
  
  CGAL_INLINE_FUNCTION
  std::ostream&
  //operator<< (std::ostream &o, mpq_srcptr q)
  io_write (std::ostream &o, mpq_srcptr q)
  { 
    // size according to GMP documentation
    char *str = new char [mpz_sizeinbase(mpq_numref(q), 10) +
                          mpz_sizeinbase (mpq_denref(q), 10) + 3];
    str = mpq_get_str(str, 10, q);
    o << str ;
    delete[] str;
    return o;
  }
  
  } //namespace CORE
  