RAllocStack.h

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/*CXXR $Id: RAllocStack.h 1348 2013-02-25 17:49:03Z 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) 2008-13 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
 *
 *  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 RALLOCSTACK_H
#define RALLOCSTACK_H 1

#include <stddef.h>

#ifdef __cplusplus

#include <stack>
#include <vector>
#include "CXXR/config.hpp"
#include "CXXR/SchwarzCounter.hpp"

namespace CXXR {
    class RAllocStack {
    public:
        class Scope {
        public:
            Scope()
#ifndef NDEBUG
                : m_next_scope(RAllocStack::s_innermost_scope),
                  m_saved_size(RAllocStack::size())
#else
                : m_saved_size(RAllocStack::size())
#endif
            {
#ifndef NDEBUG
                RAllocStack::s_innermost_scope = this;
#endif
            }

            ~Scope()
            {
                if (RAllocStack::size() != m_saved_size)
                    RAllocStack::trim(m_saved_size);
#ifndef NDEBUG
                RAllocStack::s_innermost_scope = m_next_scope;
#endif
            }

            size_t startSize() const
            {
                return m_saved_size;
            }
        private:
#ifndef NDEBUG
            Scope* m_next_scope;
#endif
            size_t m_saved_size;
        };

        static void* allocate(size_t sz);

        static void restoreSize(size_t new_size);

        static size_t size()
        {
            return s_stack->size();
        }
    private:
        typedef std::pair<size_t, void*> Pair;
        typedef std::stack<Pair, std::vector<Pair> > Stack;
        static Stack* s_stack;
#ifndef NDEBUG
        static Scope* s_innermost_scope;
#endif

        // Not implemented.  Declared to stop the compiler generating
        // a constructor.
        RAllocStack();

        // Clean up static data members:
        static void cleanup();

        // Initialize the static data members:
        static void initialize();

        // Pop entries off the stack to reduce its size to new_size,
        // which must be no greater than the current size.
        static void trim(size_t new_size);

        friend class SchwarzCounter<RAllocStack>;
    };
}  // namespace CXXR

namespace {
    CXXR::SchwarzCounter<CXXR::RAllocStack> rallocstack_schwarz_ctr;
}

extern "C" {
#endif /* __cplusplus */

    /* ***** C interface ***** */

    char* R_alloc(size_t num_elts, int elt_size);

#ifdef __cplusplus

    inline void* CXXR_alloc(size_t num_elts, int elt_size)
    {
        return static_cast<void*>(R_alloc(num_elts, elt_size));
    }
#endif

    char* S_alloc(long num_elts, int elt_size);

    char* S_realloc(char *prev_block, long new_sz, long old_sz, int elt_size);

#ifndef __cplusplus
    void* vmaxget(void);
#else
    inline void* vmaxget(void)
    {
        return static_cast<char*>(0) + CXXR::RAllocStack::size();
    }
#endif

#ifndef __cplusplus
    void vmaxset(const void* stack_sizep);
#else
    inline void vmaxset(const void* stack_sizep)
    {
        size_t stack_size = static_cast<const char*>(stack_sizep)
                            - static_cast<const char*>(0);
        CXXR::RAllocStack::restoreSize(stack_size);
    }
#endif

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

#endif  // RALLOCSTACK_H