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/*

 * Copyright (c) 1996-1998 by Silicon Graphics.  All rights reserved.

 *

 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED

 * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.

 *

 * Permission is hereby granted to use or copy this program

 * for any purpose,  provided the above notices are retained on all copies.

 * Permission to modify the code and to distribute modified code is granted,

 * provided the above notices are retained, and a notice that the code was

 * modified is included with the above copyright notice.

 */

//

// This is a revision of gc_alloc.h for SGI STL versions > 3.0

// Unlike earlier versions, it supplements the standard "alloc.h"

// instead of replacing it.

//

// This is sloppy about variable names used in header files.

// It also doesn't yet understand the new header file names or

// namespaces.

//

// This assumes the collector has been compiled with -DATOMIC_UNCOLLECTABLE.

// The user should also consider -DREDIRECT_MALLOC=GC_uncollectable_malloc,

// to ensure that object allocated through malloc are traced.

//

// Some of this could be faster in the explicit deallocation case.

// In particular, we spend too much time clearing objects on the

// free lists.  That could be avoided.

//

// This uses template classes with static members, and hence does not work

// with g++ 2.7.2 and earlier.

//

// Unlike its predecessor, this one simply defines

//      gc_alloc

//      single_client_gc_alloc

//      traceable_alloc

//      single_client_traceable_alloc

//

// It does not redefine alloc.  Nor does it change the default allocator,

// though the user may wish to do so.  (The argument against changing

// the default allocator is that it may introduce subtle link compatibility

// problems.  The argument for changing it is that the usual default

// allocator is usually a very bad choice for a garbage collected environment.)

//

// This code assumes that the collector itself has been compiled with a

// compiler that defines __STDC__ .

//

#ifndef GC_ALLOC_H

#include "gc.h"

#if (__GNUC__ < 3)

# include <stack>  // A more portable way to get stl_alloc.h .

#else

# include <bits/stl_alloc.h>

# ifndef __STL_BEGIN_NAMESPACE

# define __STL_BEGIN_NAMESPACE namespace std {

# define __STL_END_NAMESPACE };

# endif

#ifndef __STL_USE_STD_ALLOCATORS

#define __STL_USE_STD_ALLOCATORS

#endif

#endif

/* A hack to deal with gcc 3.1.  If you are using gcc3.1 and later,     */

/* you should probably really use gc_allocator.h instead.               */

#if defined (__GNUC__) && \

    (__GNUC > 3 || (__GNUC__ == 3 && (__GNUC_MINOR__ >= 1)))

# define simple_alloc __simple_alloc

#endif

#define GC_ALLOC_H

#include <stddef.h>

#include <string.h>

// The following need to match collector data structures.

// We can't include gc_priv.h, since that pulls in way too much stuff.

// This should eventually be factored out into another include file.

extern "C" {

    extern void ** const GC_objfreelist_ptr;

    extern void ** const GC_aobjfreelist_ptr;

    extern void ** const GC_uobjfreelist_ptr;

    extern void ** const GC_auobjfreelist_ptr;

    extern void GC_incr_words_allocd(size_t words);

    extern void GC_incr_mem_freed(size_t words);

    extern char * GC_generic_malloc_words_small(size_t word, int kind);

}

// Object kinds; must match PTRFREE, NORMAL, UNCOLLECTABLE, and

// AUNCOLLECTABLE in gc_priv.h.

enum { GC_PTRFREE = 0, GC_NORMAL = 1, GC_UNCOLLECTABLE = 2,

       GC_AUNCOLLECTABLE = 3 };

enum { GC_max_fast_bytes = 255 };

enum { GC_bytes_per_word = sizeof(char *) };

enum { GC_byte_alignment = 8 };

enum { GC_word_alignment = GC_byte_alignment/GC_bytes_per_word };

inline void * &GC_obj_link(void * p)

{   return *reinterpret_cast<void **>(p);  }

// Compute a number of words >= n+1 bytes.

// The +1 allows for pointers one past the end.

inline size_t GC_round_up(size_t n)

{

    return ((n + GC_byte_alignment)/GC_byte_alignment)*GC_word_alignment;

}

// The same but don't allow for extra byte.

inline size_t GC_round_up_uncollectable(size_t n)

{

    return ((n + GC_byte_alignment - 1)/GC_byte_alignment)*GC_word_alignment;

}

template <int dummy>

class GC_aux_template {

public:

  // File local count of allocated words.  Occasionally this is

  // added into the global count.  A separate count is necessary since the

  // real one must be updated with a procedure call.

  static size_t GC_words_recently_allocd;

  // Same for uncollectable mmory.  Not yet reflected in either

  // GC_words_recently_allocd or GC_non_gc_bytes.

  static size_t GC_uncollectable_words_recently_allocd;

  // Similar counter for explicitly deallocated memory.

  static size_t GC_mem_recently_freed;

  // Again for uncollectable memory.

  static size_t GC_uncollectable_mem_recently_freed;

  static void * GC_out_of_line_malloc(size_t nwords, int kind);

};

template <int dummy>

size_t GC_aux_template<dummy>::GC_words_recently_allocd = 0;

template <int dummy>

size_t GC_aux_template<dummy>::GC_uncollectable_words_recently_allocd = 0;

template <int dummy>

size_t GC_aux_template<dummy>::GC_mem_recently_freed = 0;

template <int dummy>

size_t GC_aux_template<dummy>::GC_uncollectable_mem_recently_freed = 0;

template <int dummy>

void * GC_aux_template<dummy>::GC_out_of_line_malloc(size_t nwords, int kind)

{

    GC_words_recently_allocd += GC_uncollectable_words_recently_allocd;

    GC_non_gc_bytes +=

                GC_bytes_per_word * GC_uncollectable_words_recently_allocd;

    GC_uncollectable_words_recently_allocd = 0;

    GC_mem_recently_freed += GC_uncollectable_mem_recently_freed;

    GC_non_gc_bytes -=

                GC_bytes_per_word * GC_uncollectable_mem_recently_freed;

    GC_uncollectable_mem_recently_freed = 0;

    GC_incr_words_allocd(GC_words_recently_allocd);

    GC_words_recently_allocd = 0;

    GC_incr_mem_freed(GC_mem_recently_freed);

    GC_mem_recently_freed = 0;

    return GC_generic_malloc_words_small(nwords, kind);

}

typedef GC_aux_template<0> GC_aux;

// A fast, single-threaded, garbage-collected allocator

// We assume the first word will be immediately overwritten.

// In this version, deallocation is not a noop, and explicit

// deallocation is likely to help performance.

template <int dummy>

class single_client_gc_alloc_template {

    public:

        static void * allocate(size_t n)

        {

            size_t nwords = GC_round_up(n);

            void ** flh;

            void * op;

            if (n > GC_max_fast_bytes) return GC_malloc(n);

            flh = GC_objfreelist_ptr + nwords;

            if (0 == (op = *flh)) {

                return GC_aux::GC_out_of_line_malloc(nwords, GC_NORMAL);

            }

            *flh = GC_obj_link(op);

            GC_aux::GC_words_recently_allocd += nwords;

            return op;

        }

        static void * ptr_free_allocate(size_t n)

        {

            size_t nwords = GC_round_up(n);

            void ** flh;

            void * op;

            if (n > GC_max_fast_bytes) return GC_malloc_atomic(n);

            flh = GC_aobjfreelist_ptr + nwords;

            if (0 == (op = *flh)) {

                return GC_aux::GC_out_of_line_malloc(nwords, GC_PTRFREE);

            }

            *flh = GC_obj_link(op);

            GC_aux::GC_words_recently_allocd += nwords;

            return op;

        }

        static void deallocate(void *p, size_t n)

        {

            size_t nwords = GC_round_up(n);

            void ** flh;

            if (n > GC_max_fast_bytes)  {

                GC_free(p);

            } else {

                flh = GC_objfreelist_ptr + nwords;

                GC_obj_link(p) = *flh;

                memset(reinterpret_cast<char *>(p) + GC_bytes_per_word, 0,

                       GC_bytes_per_word * (nwords - 1));

                *flh = p;

                GC_aux::GC_mem_recently_freed += nwords;

            }

        }

        static void ptr_free_deallocate(void *p, size_t n)

        {

            size_t nwords = GC_round_up(n);

            void ** flh;

            if (n > GC_max_fast_bytes) {

                GC_free(p);

            } else {

                flh = GC_aobjfreelist_ptr + nwords;

                GC_obj_link(p) = *flh;

                *flh = p;

                GC_aux::GC_mem_recently_freed += nwords;

            }

        }

};

typedef single_client_gc_alloc_template<0> single_client_gc_alloc;

// Once more, for uncollectable objects.

template <int dummy>

class single_client_traceable_alloc_template {

    public:

        static void * allocate(size_t n)

        {

            size_t nwords = GC_round_up_uncollectable(n);

            void ** flh;

            void * op;

            if (n > GC_max_fast_bytes) return GC_malloc_uncollectable(n);

            flh = GC_uobjfreelist_ptr + nwords;

            if (0 == (op = *flh)) {

                return GC_aux::GC_out_of_line_malloc(nwords, GC_UNCOLLECTABLE);

            }

            *flh = GC_obj_link(op);

            GC_aux::GC_uncollectable_words_recently_allocd += nwords;

            return op;

        }

        static void * ptr_free_allocate(size_t n)

        {

            size_t nwords = GC_round_up_uncollectable(n);

            void ** flh;

            void * op;

            if (n > GC_max_fast_bytes) return GC_malloc_atomic_uncollectable(n);

            flh = GC_auobjfreelist_ptr + nwords;

            if (0 == (op = *flh)) {

                return GC_aux::GC_out_of_line_malloc(nwords, GC_AUNCOLLECTABLE);

            }

            *flh = GC_obj_link(op);

            GC_aux::GC_uncollectable_words_recently_allocd += nwords;

            return op;

        }

        static void deallocate(void *p, size_t n)

        {

            size_t nwords = GC_round_up_uncollectable(n);

            void ** flh;

            if (n > GC_max_fast_bytes)  {

                GC_free(p);

            } else {

                flh = GC_uobjfreelist_ptr + nwords;

                GC_obj_link(p) = *flh;

                *flh = p;

                GC_aux::GC_uncollectable_mem_recently_freed += nwords;

            }

        }

        static void ptr_free_deallocate(void *p, size_t n)

        {

            size_t nwords = GC_round_up_uncollectable(n);

            void ** flh;

            if (n > GC_max_fast_bytes) {

                GC_free(p);

            } else {

                flh = GC_auobjfreelist_ptr + nwords;

                GC_obj_link(p) = *flh;

                *flh = p;

                GC_aux::GC_uncollectable_mem_recently_freed += nwords;

            }

        }

};

typedef single_client_traceable_alloc_template<0> single_client_traceable_alloc;

template < int dummy >

class gc_alloc_template {

    public:

        static void * allocate(size_t n) { return GC_malloc(n); }

        static void * ptr_free_allocate(size_t n)

                { return GC_malloc_atomic(n); }

        static void deallocate(void *, size_t) { }

        static void ptr_free_deallocate(void *, size_t) { }

};

typedef gc_alloc_template < 0 > gc_alloc;

template < int dummy >

class traceable_alloc_template {

    public:

        static void * allocate(size_t n) { return GC_malloc_uncollectable(n); }

        static void * ptr_free_allocate(size_t n)

                { return GC_malloc_atomic_uncollectable(n); }

        static void deallocate(void *p, size_t) { GC_free(p); }

        static void ptr_free_deallocate(void *p, size_t) { GC_free(p); }

};

typedef traceable_alloc_template < 0 > traceable_alloc;

// We want to specialize simple_alloc so that it does the right thing

// for all pointerfree types.  At the moment there is no portable way to

// even approximate that.  The following approximation should work for

// SGI compilers, and recent versions of g++.

# define __GC_SPECIALIZE(T,alloc) \

class simple_alloc<T, alloc> { \

public: \

    static T *allocate(size_t n) \

        { return 0 == n? 0 : \

                         reinterpret_cast<T*>(alloc::ptr_free_allocate(n * sizeof (T))); } \

    static T *allocate(void) \

        { return reinterpret_cast<T*>(alloc::ptr_free_allocate(sizeof (T))); } \

    static void deallocate(T *p, size_t n) \

        { if (0 != n) alloc::ptr_free_deallocate(p, n * sizeof (T)); } \

    static void deallocate(T *p) \

        { alloc::ptr_free_deallocate(p, sizeof (T)); } \

};

__STL_BEGIN_NAMESPACE

__GC_SPECIALIZE(char, gc_alloc)

__GC_SPECIALIZE(int, gc_alloc)

__GC_SPECIALIZE(unsigned, gc_alloc)

__GC_SPECIALIZE(float, gc_alloc)

__GC_SPECIALIZE(double, gc_alloc)

__GC_SPECIALIZE(char, traceable_alloc)

__GC_SPECIALIZE(int, traceable_alloc)

__GC_SPECIALIZE(unsigned, traceable_alloc)

__GC_SPECIALIZE(float, traceable_alloc)

__GC_SPECIALIZE(double, traceable_alloc)

__GC_SPECIALIZE(char, single_client_gc_alloc)

__GC_SPECIALIZE(int, single_client_gc_alloc)

__GC_SPECIALIZE(unsigned, single_client_gc_alloc)

__GC_SPECIALIZE(float, single_client_gc_alloc)

__GC_SPECIALIZE(double, single_client_gc_alloc)

__GC_SPECIALIZE(char, single_client_traceable_alloc)

__GC_SPECIALIZE(int, single_client_traceable_alloc)

__GC_SPECIALIZE(unsigned, single_client_traceable_alloc)

__GC_SPECIALIZE(float, single_client_traceable_alloc)

__GC_SPECIALIZE(double, single_client_traceable_alloc)

__STL_END_NAMESPACE

#ifdef __STL_USE_STD_ALLOCATORS

__STL_BEGIN_NAMESPACE

template <class _Tp>

struct _Alloc_traits<_Tp, gc_alloc >

{

  static const bool _S_instanceless = true;

  typedef simple_alloc<_Tp, gc_alloc > _Alloc_type;

  typedef __allocator<_Tp, gc_alloc > allocator_type;

};

inline bool operator==(const gc_alloc&,

                       const gc_alloc&)

{

  return true;

}

inline bool operator!=(const gc_alloc&,

                       const gc_alloc&)

{

  return false;

}

template <class _Tp>

struct _Alloc_traits<_Tp, single_client_gc_alloc >

{

  static const bool _S_instanceless = true;

  typedef simple_alloc<_Tp, single_client_gc_alloc > _Alloc_type;

  typedef __allocator<_Tp, single_client_gc_alloc > allocator_type;

};

inline bool operator==(const single_client_gc_alloc&,

                       const single_client_gc_alloc&)

{

  return true;

}

inline bool operator!=(const single_client_gc_alloc&,

                       const single_client_gc_alloc&)

{

  return false;

}

template <class _Tp>

struct _Alloc_traits<_Tp, traceable_alloc >

{

  static const bool _S_instanceless = true;

  typedef simple_alloc<_Tp, traceable_alloc > _Alloc_type;

  typedef __allocator<_Tp, traceable_alloc > allocator_type;

};

inline bool operator==(const traceable_alloc&,

                       const traceable_alloc&)

{

  return true;

}

inline bool operator!=(const traceable_alloc&,

                       const traceable_alloc&)

{

  return false;

}

template <class _Tp>

struct _Alloc_traits<_Tp, single_client_traceable_alloc >

{

  static const bool _S_instanceless = true;

  typedef simple_alloc<_Tp, single_client_traceable_alloc > _Alloc_type;

  typedef __allocator<_Tp, single_client_traceable_alloc > allocator_type;

};

inline bool operator==(const single_client_traceable_alloc&,

                       const single_client_traceable_alloc&)

{

  return true;

}

inline bool operator!=(const single_client_traceable_alloc&,

                       const single_client_traceable_alloc&)

{

  return false;

}

__STL_END_NAMESPACE

#endif /* __STL_USE_STD_ALLOCATORS */

#endif /* GC_ALLOC_H */