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Annotation of OpenXM_contrib/gmp/cxx/ismpf.cc, Revision 1.1

1.1     ! ohara       1: /* operator>> -- C++-style input of mpf_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 "config.h"
        !            23:
        !            24: #include <cctype>
        !            25: #include <iostream>
        !            26: #include <string>
        !            27:
        !            28: #if HAVE_LOCALE_H
        !            29: #include <locale.h>    /* for localeconv */
        !            30: #endif
        !            31:
        !            32: #include "gmp.h"
        !            33: #include "gmp-impl.h"
        !            34:
        !            35: using namespace std;
        !            36:
        !            37:
        !            38: /* Perhaps the decimal point should be taken from the C++ <locale> stuff,
        !            39:    but that doesn't exist in g++ 2.95.x.  In any case, using plain C
        !            40:    localeconv will ensure we parse exactly what mpf_set_str will expect, and
        !            41:    what the current operator<< implementation produces.  */
        !            42:
        !            43: istream &
        !            44: operator>> (istream &i, mpf_ptr f)
        !            45: {
        !            46:   int base;
        !            47:   char c = 0;
        !            48:   string s;
        !            49:   bool ok = false;
        !            50:
        !            51:   i.get(c); // start reading
        !            52:
        !            53:   if (i.flags() & ios::skipws) // skip initial whitespace
        !            54:     while (isspace(c) && i.get(c))
        !            55:       ;
        !            56:
        !            57:   if (c == '-' || c == '+') // sign
        !            58:     {
        !            59:       if (c == '-')
        !            60:        s = "-";
        !            61:       i.get(c);
        !            62:
        !            63:       while (isspace(c) && i.get(c)) // skip whitespace
        !            64:        ;
        !            65:     }
        !            66:
        !            67:   base = 10; // octal/hex floats currently unsupported
        !            68:   __gmp_istream_set_digits(s, i, c, ok, base); // read the number
        !            69:
        !            70: #if HAVE_LOCALECONV
        !            71:   const char  *point = localeconv()->decimal_point;
        !            72:   if (c == *point) // radix point
        !            73:     {
        !            74:       for (;;)
        !            75:         {
        !            76:           s += c;
        !            77:           i.get(c);
        !            78:           point++;
        !            79:           if (*point == '\0')
        !            80:             break;
        !            81:           if (c != *point)
        !            82:             goto fail;
        !            83:         }
        !            84:       __gmp_istream_set_digits(s, i, c, ok, base); // read the mantissa
        !            85:     }
        !            86: #else
        !            87:   if (c == '.') // radix point
        !            88:     {
        !            89:       s += '.';
        !            90:       i.get(c);
        !            91:       __gmp_istream_set_digits(s, i, c, ok, base); // read the mantissa
        !            92:     }
        !            93: #endif
        !            94:
        !            95:   if (ok && (c == 'e' || c == 'E' || c == '@')) // exponent
        !            96:     {
        !            97:       s += c;
        !            98:       i.get(c);
        !            99:       ok = false; // exponent is mandatory
        !           100:
        !           101:       if (c == '-' || c == '+') // sign
        !           102:        {
        !           103:          s += c;
        !           104:          i.get(c);
        !           105:
        !           106:          while (isspace(c) && i.get(c)) // skip whitespace
        !           107:            ;
        !           108:        }
        !           109:
        !           110:       __gmp_istream_set_digits(s, i, c, ok, base); // read the exponent
        !           111:     }
        !           112:
        !           113:   if (i.good()) // last character read was non-numeric
        !           114:     i.putback(c);
        !           115:   else if (i.eof() && ok) // stopped just before eof
        !           116:     i.clear();
        !           117:
        !           118:   if (ok)
        !           119:     mpf_set_str(f, s.c_str(), base); // extract the number
        !           120:   else
        !           121:     {
        !           122:     fail:
        !           123:       i.setstate(ios::failbit); // read failed
        !           124:     }
        !           125:
        !           126:   return i;
        !           127: }