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/*
* Copyright 1998-2002 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code 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 General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*
*/
// All classes in the virtual machine must be subclassed
// by one of the following allocation classes:
//
//
// For objects allocated in the C-heap (managed by: free & malloc).
// - CHeapObj
//
//
// For embedded objects.
// - ValueObj
//
// For classes used as name spaces.
// - AllStatic
//
class CHeapObj {
public:
void* operator new(size_t size);
void operator delete(void* p);
void* new_array(size_t size);
};
// Base class for objects used as value objects.
// Calling new or delete will result in fatal error.
class ValueObj {
public:
void* operator new(size_t size);
void operator delete(void* p);
};
// Base class for classes that constitute name spaces.
class AllStatic {
public:
void* operator new(size_t size);
void operator delete(void* p);
};
//------------------------------Chunk------------------------------------------
// Linked list of raw memory chunks
class Chunk: public CHeapObj {
public:
void* operator new(size_t size, size_t length);
void operator delete(void* p, size_t length);
Chunk(size_t length);
enum {
init_size = 1*1024, // Size of first chunk
size = 32*1024 // Default size of an Arena chunk (following the first)
};
Chunk* _next; // Next Chunk in list
size_t _len; // Size of this Chunk
void chop(); // Chop this chunk
void next_chop(); // Chop next chunk
// Boundaries of data area (possibly unused)
char* bottom() const { return ((char*) this) + sizeof(Chunk); }
char* top() const { return bottom() + _len; }
};
//------------------------------Arena------------------------------------------
// Fast allocation of memory
class Arena: public CHeapObj {
protected:
friend class ResourceMark;
friend class HandleMark;
friend class NoHandleMark;
Chunk *_first; // First chunk
Chunk *_chunk; // current chunk
char *_hwm, *_max; // High water mark and max in current chunk
void* grow(size_t x); // Get a new Chunk of at least size x
size_t _size_in_bytes; // Size of arena (used for memory usage tracing)
public:
Arena();
Arena(size_t init_size);
Arena(Arena *old);
~Arena() { _first->chop(); }
char* hwm() const { return _hwm; }
// Fast allocate in the arena. Common case is: pointer test + increment.
void* Amalloc(size_t x) {
#ifdef _LP64
x = (x + (8-1)) & ((unsigned)(-8));
#else
x = (x + (4-1)) & ((unsigned)(-4));
#endif
if (_hwm + x > _max) {
return grow(x);
} else {
char *old = _hwm;
_hwm += x;
return old;
}
}
// Further assume size is padded out to words
// Warning: in LP64, Amalloc_4 is really Amalloc_8
void *Amalloc_4(size_t x) {
assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" );
if (_hwm + x > _max) {
return grow(x);
} else {
char *old = _hwm;
_hwm += x;
return old;
}
}
// Fast delete in area. Common case is: NOP (except for storage reclaimed)
void Afree(void *ptr, size_t size) {
if (((char*)ptr) + size == _hwm) _hwm = (char*)ptr;
}
void *Acalloc( size_t items, size_t x );
void *Arealloc( void *old_ptr, size_t old_size, size_t new_size );
// Reset this Arena to empty, and return this Arenas guts in a new Arena.
Arena *reset(void);
// Determine if pointer belongs to this Arena or not.
bool contains( const void *ptr ) const;
// Total of all chunks in use (not thread-safe)
size_t used() const;
// Total # of bytes used
size_t size_in_bytes() const { return _size_in_bytes; }
void set_size_in_bytes(size_t size) { _size_in_bytes = size; }
};
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