ReadHex.C

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/*---------------------------------------------------------------------------*\
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-------------------------------------------------------------------------------
    Copyright (C) 2013-2015 OpenFOAM Foundation
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.
 
    OpenFOAM is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.
 
    You should have received a copy of the GNU General Public License
    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
Description
    Read a non-delimited hex label
 
\*---------------------------------------------------------------------------*/
 
#include "ReadHex.H"
#include <cctype>
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
template<class T>
T Foam::ReadHex(ISstream& is)
{
    // The char '0' == 0
    static constexpr int offsetZero = int('0');
 
    // The char 'A' (or 'a') == 10
    static constexpr int offsetAlpha = int('A') - 10;
 
    char c = 0;
 
    // Get next non-whitespace character
    while (is.get(c) && isspace(c))
    {}
 
    T result = 0;
    do
    {
        if (isspace(c) || c == 0) break;
 
        if (!isxdigit(c))
        {
            FatalIOErrorInFunction(is)
                << "Illegal hex digit: '" << c << "'"
                << exit(FatalIOError);
        }
 
        result <<= 4;
 
        if (isdigit(c))
        {
            result += int(c) - offsetZero;
        }
        else
        {
            result += toupper(c) - offsetAlpha;
        }
    } while (is.get(c));
 
    return result;
}
 
 
// ************************************************************************* //