/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements. See the NOTICE file distributed
 *   with this work for additional information regarding copyright
 *   ownership. The ASF licenses this file to you under the Apache
 *   License, Version 2.0 (the "License"); you may not use this file
 *   except in compliance with the License. You may obtain a copy of
 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
 */

#include <algorithm>
#include <new>
#include <string.h>
#include <osl/diagnose.h>
#include <rtl/alloc.h>

// AllocatorTraits

namespace
{

struct AllocatorTraits
{
    typedef char const signature_type[8];
    const signature_type & m_signature;

    explicit AllocatorTraits (signature_type const & s)
        : m_signature (s)
    {}

    std::size_t size (std::size_t n) const
    {
        n = std::max(n, std::size_t(1));
#if OSL_DEBUG_LEVEL > 0
        n += sizeof(signature_type);
#endif  /* OSL_DEBUG_LEVEL  */
        return n;
    }

    void* init (void * p) const
    {
#if OSL_DEBUG_LEVEL > 0
        memcpy (p, m_signature, sizeof(signature_type));
        p = static_cast<char*>(p) + sizeof(signature_type);
#endif  /* OSL_DEBUG_LEVEL */
        return p;
    }

    void* fini (void * p) const
    {
#if OSL_DEBUG_LEVEL > 0
        p = static_cast<char*>(p) - sizeof(signature_type);
        if (memcmp (p, m_signature, sizeof(signature_type)) != 0)
        {
            OSL_FAIL("operator delete mismatch");
        }
#endif  /* OSL_DEBUG_LEVEL */
        return p;
    }
};

struct VectorTraits : public AllocatorTraits
{
    static const signature_type g_signature;

    VectorTraits()
        : AllocatorTraits (g_signature)
    {}
};

struct ScalarTraits : public AllocatorTraits
{
    static const signature_type g_signature;

    ScalarTraits()
        : AllocatorTraits (g_signature)
    {}
};

const AllocatorTraits::signature_type VectorTraits::g_signature = "new[]()";
const AllocatorTraits::signature_type ScalarTraits::g_signature = "new()  ";

} // anonymous namespace

// Allocator

static void default_handler (void)
{
    // Multithreading race in 'std::set_new_handler()' call sequence below.
    throw std::bad_alloc();
}

static void* allocate (
    std::size_t n, AllocatorTraits const & rTraits)
{
    n = rTraits.size (n);
    for (;;)
    {
        void * p = rtl_allocateMemory (sal_Size(n));
        if (p != 0)
            return rTraits.init (p);

        std::new_handler d = default_handler, f = std::set_new_handler (d);
        if (f != d)
            std::set_new_handler (f);

        if (f == 0)
            throw std::bad_alloc();
        (*f)();
    }
}

static void* allocate_nothrow (
    std::size_t n, AllocatorTraits const & rTraits)
{
    try
    {
        return allocate (n, rTraits);
    }
    catch (std::bad_alloc const &)
    {
        return (0);
    }
}

static void deallocate (void * p, AllocatorTraits const & rTraits)
{
    if (p)
    {
        rtl_freeMemory (rTraits.fini(p));
    }
}

// T * p = new T; delete p;

void* SAL_CALL operator new (std::size_t n) throw (std::bad_alloc)
{
    return allocate (n, ScalarTraits());
}

void SAL_CALL operator delete (void * p) throw ()
{
    deallocate (p, ScalarTraits());
}

// T * p = new(nothrow) T; delete(nothrow) p;

void* SAL_CALL operator new (std::size_t n, std::nothrow_t const &) throw ()
{
    return allocate_nothrow (n, ScalarTraits());
}

void SAL_CALL operator delete (void * p, std::nothrow_t const &) throw ()
{
    deallocate (p, ScalarTraits());
}

// T * p = new T[n]; delete[] p;

void* SAL_CALL operator new[] (std::size_t n) throw (std::bad_alloc)
{
    return allocate (n, VectorTraits());
}

void SAL_CALL operator delete[] (void * p) throw ()
{
    deallocate (p, VectorTraits());
}

// T * p = new(nothrow) T[n]; delete(nothrow)[] p;

void* SAL_CALL operator new[] (std::size_t n, std::nothrow_t const &) throw ()
{
    return allocate_nothrow (n, VectorTraits());
}

void SAL_CALL operator delete[] (void * p, std::nothrow_t const &) throw ()
{
    deallocate (p, VectorTraits());
}

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */