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Annotation of OpenXM_contrib/gmp/cxx/ismpq.cc, Revision 1.1.1.1

1.1       ohara       1: /* operator>> -- C++-style input of mpq_t.
                      2:
                      3: Copyright 2001, 2002 Free Software Foundation, Inc.
                      4:
                      5: This file is part of the GNU MP Library.
                      6:
                      7: The GNU MP Library is free software; you can redistribute it and/or modify
                      8: it under the terms of the GNU Lesser General Public License as published by
                      9: the Free Software Foundation; either version 2.1 of the License, or (at your
                     10: option) any later version.
                     11:
                     12: The GNU MP Library is distributed in the hope that it will be useful, but
                     13: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
                     14: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
                     15: License for more details.
                     16:
                     17: You should have received a copy of the GNU Lesser General Public License
                     18: along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
                     19: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
                     20: MA 02111-1307, USA. */
                     21:
                     22: #include <cctype>
                     23: #include <iostream>
                     24: #include <string>
                     25: #include "gmp.h"
                     26: #include "gmp-impl.h"
                     27:
                     28: using namespace std;
                     29:
                     30:
                     31: istream &
                     32: operator>> (istream &i, mpq_ptr q)
                     33: {
                     34:   int base;
                     35:   char c = 0;
                     36:   string s;
                     37:   bool ok = false, zero, showbase;
                     38:
                     39:   i.get(c); // start reading
                     40:
                     41:   if (i.flags() & ios::skipws) // skip initial whitespace
                     42:     while (isspace(c) && i.get(c))
                     43:       ;
                     44:
                     45:   if (c == '-' || c == '+') // sign
                     46:     {
                     47:       if (c == '-')
                     48:        s = "-";
                     49:       i.get(c);
                     50:
                     51:       while (isspace(c) && i.get(c)) // skip whitespace
                     52:        ;
                     53:     }
                     54:
                     55:   base = __gmp_istream_set_base(i, c, zero, showbase); // select the base
                     56:   __gmp_istream_set_digits(s, i, c, ok, base);         // read the numerator
                     57:
                     58:   if (! ok && zero) // the only digit read was "0"
                     59:     {
                     60:       base = 10;
                     61:       s += '0';
                     62:       ok = true;
                     63:     }
                     64:
                     65:   if (i.flags() & ios::skipws)
                     66:     while (isspace(c) && i.get(c)) // skip whitespace
                     67:       ;
                     68:
                     69:   if (c == '/') // there's a denominator
                     70:     {
                     71:       bool zero2 = false;
                     72:       int base2 = base;
                     73:
                     74:       s += '/';
                     75:       ok = false; // denominator is mandatory
                     76:       i.get(c);
                     77:
                     78:       while (isspace(c) && i.get(c)) // skip whitespace
                     79:        ;
                     80:
                     81:       if (showbase) // check base of denominator
                     82:        base2 = __gmp_istream_set_base(i, c, zero2, showbase);
                     83:
                     84:       if (base2 == base || base2 == 10) // read the denominator
                     85:        __gmp_istream_set_digits(s, i, c, ok, base);
                     86:
                     87:       if (! ok && zero2) // the only digit read was "0"
                     88:        {                // denominator is 0, but that's your business
                     89:          s += '0';
                     90:          ok = true;
                     91:        }
                     92:     }
                     93:
                     94:   if (i.good()) // last character read was non-numeric
                     95:     i.putback(c);
                     96:   else if (i.eof() && ok) // stopped just before eof
                     97:     i.clear();
                     98:
                     99:   if (ok)
                    100:     mpq_set_str(q, s.c_str(), base); // extract the number
                    101:   else
                    102:     i.setstate(ios::failbit); // read failed
                    103:
                    104:   return i;
                    105: }