141 lines
3.6 KiB
C++
141 lines
3.6 KiB
C++
/* operator>> -- C++-style input of mpf_t.
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Copyright 2001, 2003 Free Software Foundation, Inc.
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Copyright 2009 William Hart
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This file is part of the GNU MP Library.
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The GNU MP Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or (at your
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option) any later version.
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The GNU MP Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the GNU MP Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#include <cctype>
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#include <iostream>
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#include <string>
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#include <clocale> // for localeconv
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#include "mpir.h"
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#include "gmp-impl.h"
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using namespace std;
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// For g++ libstdc++ parsing see num_get<chartype,initer>::_M_extract_float
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// in include/bits/locale_facets.tcc.
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//
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// There are no plans to accept hex or octal floats, not unless the standard
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// C++ library does so. Although such formats might be of use, it's
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// considered more important to be compatible with what the normal
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// operator>> does on "double"s etc.
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istream &
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operator>> (istream &i, mpf_ptr f)
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{
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int base;
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char c = 0;
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string s;
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bool ok = false;
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// C decimal point, as expected by mpf_set_str
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const char *lconv_point = localeconv()->decimal_point;
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// C++ decimal point
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#if HAVE_STD__LOCALE && !defined (__sun) && !(defined(__APPLE_CC__) && (__APPLE_CC__ > 1))
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const locale& loc = i.getloc();
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char point_char = use_facet< numpunct<char> >(loc).decimal_point();
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#else
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const char *point = lconv_point;
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char point_char = *point;
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#endif
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i.get(c); // start reading
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if (i.flags() & ios::skipws) // skip initial whitespace
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{
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// C++ isspace
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#if HAVE_STD__LOCALE && !defined(__sun) && !(defined(__APPLE_CC__) && (__APPLE_CC__ > 1))
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const ctype<char>& ct = use_facet< ctype<char> >(loc);
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#define cxx_isspace(c) (ct.is(ctype_base::space,(c)))
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#else
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#define cxx_isspace(c) isspace(c)
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#endif
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while (cxx_isspace(c) && i.get(c))
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;
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}
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if (c == '-' || c == '+') // sign
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{
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if (c == '-')
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s = "-";
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i.get(c);
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}
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base = 10;
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__gmp_istream_set_digits(s, i, c, ok, base); // read the number
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// look for the C++ radix point, but put the C one in for mpf_set_str
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if (c == point_char)
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{
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#if HAVE_STD__LOCALE
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i.get(c);
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#else // lconv point can be multi-char
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for (;;)
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{
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i.get(c);
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point++;
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if (*point == '\0')
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break;
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if (c != *point)
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goto fail;
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}
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#endif
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s += lconv_point;
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__gmp_istream_set_digits(s, i, c, ok, base); // read the mantissa
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}
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if (ok && (c == 'e' || c == 'E')) // exponent
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{
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s += c;
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i.get(c);
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ok = false; // exponent is mandatory
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if (c == '-' || c == '+') // sign
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{
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s += c;
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i.get(c);
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}
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__gmp_istream_set_digits(s, i, c, ok, base); // read the exponent
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}
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if (i.good()) // last character read was non-numeric
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i.putback(c);
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else if (i.eof() && ok) // stopped just before eof
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i.clear();
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if (ok)
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ASSERT_NOCARRY (mpf_set_str(f, s.c_str(), base)); // extract the number
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else
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{
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#if !HAVE_STD__LOCALE
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fail:
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#endif
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i.setstate(ios::failbit); // read failed
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}
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return i;
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}
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