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Annotation of OpenXM_contrib/gmp/cxx/ismpq.cc, Revision 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: }