UncachedString.h

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/*CXXR $Id: UncachedString.h 1254 2012-01-03 15:54:03Z arr $
 *CXXR
 *CXXR This file is part of CXXR, a project to refactor the R interpreter
 *CXXR into C++.  It may consist in whole or in part of program code and
 *CXXR documentation taken from the R project itself, incorporated into
 *CXXR CXXR (and possibly MODIFIED) under the terms of the GNU General Public
 *CXXR Licence.
 *CXXR 
 *CXXR CXXR is Copyright (C) 2008-12 Andrew R. Runnalls, subject to such other
 *CXXR copyrights and copyright restrictions as may be stated below.
 *CXXR 
 *CXXR CXXR is not part of the R project, and bugs and other issues should
 *CXXR not be reported via r-bugs or other R project channels; instead refer
 *CXXR to the CXXR website.
 *CXXR */

/*
 *  R : A Computer Language for Statistical Data Analysis
 *  Copyright (C) 1995, 1996  Robert Gentleman and Ross Ihaka
 *  Copyright (C) 1999-2006   The R Development Core Team.
 *
 *  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 2.1 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 Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, a copy is available at
 *  http://www.r-project.org/Licenses/
 */

#ifndef UNCACHEDSTRING_H
#define UNCACHEDSTRING_H

#include "CXXR/String.h"

#ifdef __cplusplus

#include <string>

namespace CXXR {
    class UncachedString : public String {
    public:
        explicit UncachedString(size_t sz, cetype_t encoding = CE_NATIVE)
            : String(sz, encoding), m_databytes(sz + 1), m_data(m_short_string)
        {
            allocData(sz);
            setCString(m_data);
        }

        explicit UncachedString(const std::string& str,
                                cetype_t encoding = CE_NATIVE);

        char* ptr()
        {
            invalidateHash();
            return m_data;
        }

        static const char* staticTypeName()
        {
            return "char (uncached)";
        }

        // Virtual function of RObject:
        const char* typeName() const;
    private:
        // Max. strlen stored internally:
        static const size_t s_short_strlen = 7;

        size_t m_databytes;  // includes trailing null byte
        char* m_data;  // pointer to the string's data block.

        // If there are fewer than s_short_strlen+1 chars in the
        // string (including the trailing null), it is stored here,
        // internally to the UncachedString object, rather than via a separate
        // allocation from CXXR::MemoryBank.  We put this last, so that it
        // will be adjacent to any trailing redzone.
        char m_short_string[s_short_strlen + 1];

        // Not implemented yet.  Declared to prevent
        // compiler-generated versions:
        UncachedString(const UncachedString&);
        UncachedString& operator=(const UncachedString&);

        // Declared private to ensure that UncachedString objects are
        // allocated only using 'new'.
        ~UncachedString()
        {
            if (m_data != m_short_string)
                MemoryBank::deallocate(m_data, m_databytes);
        }

        // Initialise m_data, if necessary by allocating a data block
        // from MemoryBank:
        void allocData(size_t sz);
    };
}  // namespace CXXR

extern "C" {

#endif /* __cplusplus */

#ifndef __cplusplus
    char *CHAR_RW(SEXP x);
#else
    inline char *CHAR_RW(SEXP x)
    {
        using namespace CXXR;
        return SEXP_downcast<UncachedString*>(x)->ptr();
    }
#endif

#ifdef __cplusplus
}  // extern "C"
#endif

#endif /* UNCACHEDSTRING_H */