_alloc.h

MONA是为数不多的C++语言编写的一个很小的操作系统

/*
 *
 * Copyright (c) 1996,1997
 * Silicon Graphics Computer Systems, Inc.
 *
 * Copyright (c) 1997
 * Moscow Center for SPARC Technology
 *
 * Copyright (c) 1999 
 * Boris Fomitchev
 *
 * This material is provided "as is", with absolutely no warranty expressed
 * or implied. Any use is at your own risk.
 *
 * Permission to use or copy this software for any purpose is hereby granted 
 * without fee, 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.
 *
 */

/* NOTE: This is an internal header file, included by other STL headers.
 *   You should not attempt to use it directly.
 */

#ifndef _STLP_INTERNAL_ALLOC_H
#define _STLP_INTERNAL_ALLOC_H

# ifndef _STLP_CSTDDEF
///#  include <cstddef>
# endif

#if !defined (_STLP_DEBUG_H) && (defined  (_STLP_DEBUG) || defined (_STLP_ASSERTIONS))
# include <stl/debug/_debug.h>
#endif

# ifndef _STLP_CSTDLIB
///#  include <cstdlib>
# endif
# ifndef _STLP_CSTRING
///#  include <cstring>
# endif

# ifndef __THROW_BAD_ALLOC
#  if !defined(_STLP_USE_EXCEPTIONS)
#   if !defined (_STLP_CSTDIO)
///#    include <cstdio>
#   endif
#   if !defined (_STLP_CSTDLIB)
///#    include <cstdlib>
#   endif
#   define __THROW_BAD_ALLOC puts("out of memory\n"); exit(1)
#  else /* !defined(_STLP_USE_EXCEPTIONS) */
#   define __THROW_BAD_ALLOC throw _STLP_STD::bad_alloc()
#  endif /* !defined(_STLP_USE_EXCEPTIONS) */
# endif   /* __THROW_BAD_ALLOC */

# ifndef _STLP_INTERNAL_NEW_HEADER
#  include <stl/_new.h>
# endif

#if /* defined (_STLP_THREADS) && */ ! defined (_STLP_INTERNAL_THREADS_H)
# include <stl/_threads.h>
#endif

#ifndef _STLP_INTERNAL_CONSTRUCT_H
# include <stl/_construct.h>
#endif

#ifndef __ALLOC
#   define __ALLOC __sgi_alloc
#endif

# ifndef __RESTRICT
#  define __RESTRICT
# endif

#if defined (_STLP_THREADS) || (defined(_STLP_OWN_IOSTREAMS) && ! defined (_STLP_NO_THREADS) && ! defined (_NOTHREADS) )
# define _STLP_NODE_ALLOCATOR_THREADS true
#else
# define _STLP_NODE_ALLOCATOR_THREADS false
#endif

_STLP_BEGIN_NAMESPACE

# if defined (_STLP_USE_RAW_SGI_ALLOCATORS)
template <class _Tp, class _Alloc> struct __allocator;
# endif

// Malloc-based allocator.  Typically slower than default alloc below.
// Typically thread-safe and more storage efficient.

typedef void (* __oom_handler_type)();

template <int __inst>
class __malloc_alloc {
private:
  static void* _STLP_CALL _S_oom_malloc(size_t);
  static __oom_handler_type __oom_handler;
public:
  // this one is needed for proper simple_alloc wrapping
  typedef char value_type;
# if defined (_STLP_MEMBER_TEMPLATE_CLASSES) && defined (_STLP_USE_RAW_SGI_ALLOCATORS)
  template <class _Tp1> struct rebind {
    typedef __allocator<_Tp1, __malloc_alloc<__inst> > other;
  };
# endif
  static void* _STLP_CALL allocate(size_t __n)    {
    void* __result = malloc(__n);
    if (0 == __result) __result = _S_oom_malloc(__n);
    return __result;
  }
  static void _STLP_CALL deallocate(void* __p, size_t /* __n */) { free((char*)__p); }
  static __oom_handler_type _STLP_CALL set_malloc_handler(__oom_handler_type __f) {
    __oom_handler_type __old = __oom_handler;
    __oom_handler = __f;
    return(__old);
  }
};


// New-based allocator.  Typically slower than default alloc below.
// Typically thread-safe and more storage efficient.
class _STLP_CLASS_DECLSPEC __new_alloc {
public:
  // this one is needed for proper simple_alloc wrapping
  typedef char value_type;
# if defined (_STLP_MEMBER_TEMPLATE_CLASSES) &&  defined(_STLP_USE_RAW_SGI_ALLOCATORS)
  template <class _Tp1> struct rebind {
    typedef __allocator<_Tp1, __new_alloc > other;
  };
# endif
  static void* _STLP_CALL  allocate(size_t __n) {  return __stl_new(__n); }
  static void _STLP_CALL deallocate(void* __p, size_t) { __stl_delete(__p); }
};


// Allocator adaptor to check size arguments for debugging.
// Reports errors using assert.  Checking can be disabled with
// NDEBUG, but it's far better to just use the underlying allocator
// instead when no checking is desired.
// There is some evidence that this can confuse Purify.
// This adaptor can only be applied to raw allocators

template <class _Alloc>
class __debug_alloc : public _Alloc {
public:
  typedef _Alloc __allocator_type;
  typedef typename _Alloc::value_type value_type;
private:
  struct __alloc_header {
    size_t __magic: 16;
    size_t __type_size:16;
    _STLP_UINT32_T _M_size;
  }; // that is 8 bytes for sure
  // Sunpro CC has bug on enums, so extra_before/after set explicitly
  enum { __pad=8, __magic=0xdeba, __deleted_magic = 0xdebd,
	 __shred_byte= _STLP_SHRED_BYTE
  };

  enum { __extra_before = 16, __extra_after = 8 };
  // Size of space used to store size.  Note
  // that this must be large enough to preserve
  // alignment.
  static size_t _STLP_CALL __extra_before_chunk() {
    return (long)__extra_before/sizeof(value_type)+
      (size_t)((long)__extra_before%sizeof(value_type)>0);
  }
  static size_t _STLP_CALL __extra_after_chunk() {
    return (long)__extra_after/sizeof(value_type)+
      (size_t)((long)__extra_after%sizeof(value_type)>0);
  }
public:
# if defined (_STLP_MEMBER_TEMPLATE_CLASSES) && defined (_STLP_USE_RAW_SGI_ALLOCATORS)
  template <class _Tp1> struct rebind {
    typedef __allocator< _Tp1, __debug_alloc<_Alloc> > other;
  };
# endif
  __debug_alloc() {}
  ~__debug_alloc() {}
  static void * _STLP_CALL allocate(size_t);
  static void _STLP_CALL deallocate(void *, size_t);
};


// Default node allocator.
// With a reasonable compiler, this should be roughly as fast as the
// original STL class-specific allocators, but with less fragmentation.
// Default_alloc_template parameters are experimental and MAY
// DISAPPEAR in the future.  Clients should just use alloc for now.
//
// Important implementation properties:
// 1. If the client request an object of size > _MAX_BYTES, the resulting
//    object will be obtained directly from malloc.
// 2. In all other cases, we allocate an object of size exactly
//    _S_round_up(requested_size).  Thus the client has enough size
//    information that we can return the object to the proper free list
//    without permanently losing part of the object.
//

// The first template parameter specifies whether more than one thread
// may use this allocator.  It is safe to allocate an object from
// one instance of a default_alloc and deallocate it with another
// one.  This effectively transfers its ownership to the second one.
// This may have undesirable effects on reference locality.
// The second parameter is unreferenced and serves only to allow the
// creation of multiple default_alloc instances.

# if defined(__OS400__)
enum {_ALIGN = 16, _ALIGN_SHIFT=4, _MAX_BYTES = 256};
#  define  _STLP_NFREELISTS 16
# else
enum {_ALIGN = 8, _ALIGN_SHIFT=3, _MAX_BYTES = 128};
#  define  _STLP_NFREELISTS 16
# endif /* __OS400__ */

class _STLP_CLASS_DECLSPEC _Node_alloc_obj {
public:
    _Node_alloc_obj * _M_free_list_link;
};

template <bool __threads, int __inst>
class __node_alloc {
  _STLP_PRIVATE:
  static inline size_t _STLP_CALL _S_round_up(size_t __bytes) { return (((__bytes) + (size_t)_ALIGN-1) & ~((size_t)_ALIGN - 1)); }
  typedef _Node_alloc_obj _Obj;
private:
  // Returns an object of size __n, and optionally adds to size __n free list.
  static void*  _STLP_CALL _S_refill(size_t __n);
  // Allocates a chunk for nobjs of size size.  nobjs may be reduced
  // if it is inconvenient to allocate the requested number.
  static char*  _STLP_CALL _S_chunk_alloc(size_t __p_size, int& __nobjs);
  // Chunk allocation state.
  static _Node_alloc_obj * _STLP_VOLATILE _S_free_list[_STLP_NFREELISTS]; 
  static char* _S_start_free;
  static char* _S_end_free;
  static size_t _S_heap_size;
  static void * _STLP_CALL _M_allocate(size_t __n);
  /* __p may not be 0 */
  static void _STLP_CALL _M_deallocate(void *__p, size_t __n);
public:
  // this one is needed for proper simple_alloc wrapping
  typedef char value_type;
# if defined (_STLP_MEMBER_TEMPLATE_CLASSES) && defined (_STLP_USE_RAW_SGI_ALLOCATORS)
  template <class _Tp1> struct rebind {
    typedef __allocator<_Tp1, __node_alloc<__threads, __inst> > other;
  };
# endif
  /* __n must be > 0      */
  static void * _STLP_CALL allocate(size_t __n) { return (__n > (size_t)_MAX_BYTES) ?  __stl_new(__n) : _M_allocate(__n); }
  /* __p may not be 0 */
  static void _STLP_CALL deallocate(void *__p, size_t __n) { if (__n > (size_t)_MAX_BYTES) __stl_delete(__p); else _M_deallocate(__p, __n); }
};

# if defined (_STLP_USE_TEMPLATE_EXPORT)
_STLP_EXPORT_TEMPLATE_CLASS __malloc_alloc<0>;
_STLP_EXPORT_TEMPLATE_CLASS __node_alloc<_STLP_NODE_ALLOCATOR_THREADS, 0>;
# endif /* _STLP_USE_TEMPLATE_EXPORT */
typedef __node_alloc<_STLP_NODE_ALLOCATOR_THREADS, 0> _Node_alloc;
# if defined (_STLP_USE_TEMPLATE_EXPORT)
_STLP_EXPORT_TEMPLATE_CLASS __debug_alloc<_Node_alloc>;
_STLP_EXPORT_TEMPLATE_CLASS __debug_alloc<__new_alloc>;
_STLP_EXPORT_TEMPLATE_CLASS __debug_alloc<__malloc_alloc<0> >;
# endif