torc/common/NullOutputStream.hpp

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// Torc - Copyright 2011 University of Southern California.  All Rights Reserved.
// $HeadURL: https://torc-isi.svn.sourceforge.net/svnroot/torc-isi/branches/staging/0.9/src/torc/common/NullOutputStream.hpp $
// $Id: NullOutputStream.hpp 10 2011-10-12 18:40:16Z nsteiner $

// This program 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.
// 
// This program 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 this program.  If 
// not, see <http://www.gnu.org/licenses/>.

/// \file
/// \brief Header for the NullOutputStream class.
/// \details Credit for this code goes to Dietmar Kuehl for a July 22, 2005 response to a post on
///     http://bytes.com/topic/c/answers/127843-null-output-stream#post444998.

#ifndef TORC_COMMON_NULLOUTPUTSTREAM_HPP
#define TORC_COMMON_NULLOUTPUTSTREAM_HPP

#include <ostream>

namespace torc {
namespace common {

    /// \brief Null stream buffer used by NullOutputStream.
    /// \details Note that this stream buffer is not necessary for the NullOutputStream if we do 
    ///     not care about the stream's badbit being set.
    class NullStreamBuffer : public std::streambuf {
        /// \brief Responds that we never overflow our buffer, and can thus keep writing 
        ///     indefinitely.
        int overflow(int c) { return traits_type::not_eof(c); }
    };

    /// \brief Output stream that discards everything it receives.
    class NullOutputStream : public std::ostream {
    protected:
    // members
        /// \brief The null stream buffer that supports our operations.
        NullStreamBuffer mNullStreamBuf;
    public:
    // constructors
        /// \brief Public constructor.
        /// \details Constructs this output stream with a null stream buffer.
        NullOutputStream(void) : std::ios(&mNullStreamBuf), std::ostream(&mNullStreamBuf) {}
    };

    extern NullOutputStream cnull;

} // namespace common
} // namespace torc

#endif // TORC_COMMON_NULLOUTPUTSTREAM_HPP

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