duke@435: /*
coleenp@5614:  * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
stefank@2314: #ifndef SHARE_VM_MEMORY_MEMREGION_HPP
stefank@2314: #define SHARE_VM_MEMORY_MEMREGION_HPP
stefank@2314: 
stefank@2314: #include "memory/allocation.hpp"
stefank@2314: #include "utilities/debug.hpp"
stefank@2314: #include "utilities/globalDefinitions.hpp"
stefank@2314: 
duke@435: // A very simple data structure representing a contigous region
duke@435: // region of address space.
duke@435: 
duke@435: // Note that MemRegions are passed by value, not by reference.
duke@435: // The intent is that they remain very small and contain no
minqi@5103: // objects. _ValueObj should never be allocated in heap but we do
minqi@5103: // create MemRegions (in CardTableModRefBS) in heap so operator
minqi@5103: // new and operator new [] added for this special case.
duke@435: 
coleenp@4037: class MetaWord;
coleenp@4037: 
duke@435: class MemRegion VALUE_OBJ_CLASS_SPEC {
duke@435:   friend class VMStructs;
duke@435: private:
duke@435:   HeapWord* _start;
duke@435:   size_t    _word_size;
duke@435: 
duke@435: public:
duke@435:   MemRegion() : _start(NULL), _word_size(0) {};
duke@435:   MemRegion(HeapWord* start, size_t word_size) :
duke@435:     _start(start), _word_size(word_size) {};
duke@435:   MemRegion(HeapWord* start, HeapWord* end) :
duke@435:     _start(start), _word_size(pointer_delta(end, start)) {
duke@435:     assert(end >= start, "incorrect constructor arguments");
duke@435:   }
coleenp@4037:   MemRegion(MetaWord* start, MetaWord* end) :
coleenp@4037:     _start((HeapWord*)start), _word_size(pointer_delta(end, start)) {
coleenp@4037:     assert(end >= start, "incorrect constructor arguments");
coleenp@4037:   }
duke@435: 
duke@435:   MemRegion(const MemRegion& mr): _start(mr._start), _word_size(mr._word_size) {}
duke@435: 
duke@435:   MemRegion intersection(const MemRegion mr2) const;
duke@435:   // regions must overlap or be adjacent
duke@435:   MemRegion _union(const MemRegion mr2) const;
duke@435:   // minus will fail a guarantee if mr2 is interior to this,
duke@435:   // since there's no way to return 2 disjoint regions.
duke@435:   MemRegion minus(const MemRegion mr2) const;
duke@435: 
duke@435:   HeapWord* start() const { return _start; }
duke@435:   HeapWord* end() const   { return _start + _word_size; }
duke@435:   HeapWord* last() const  { return _start + _word_size - 1; }
duke@435: 
duke@435:   void set_start(HeapWord* start) { _start = start; }
duke@435:   void set_end(HeapWord* end)     { _word_size = pointer_delta(end, _start); }
duke@435:   void set_word_size(size_t word_size) {
duke@435:     _word_size = word_size;
duke@435:   }
duke@435: 
duke@435:   bool contains(const MemRegion mr2) const {
duke@435:     return _start <= mr2._start && end() >= mr2.end();
duke@435:   }
duke@435:   bool contains(const void* addr) const {
duke@435:     return addr >= (void*)_start && addr < (void*)end();
duke@435:   }
duke@435:   bool equals(const MemRegion mr2) const {
duke@435:     // first disjunct since we do not have a canonical empty set
duke@435:     return ((is_empty() && mr2.is_empty()) ||
duke@435:             (start() == mr2.start() && end() == mr2.end()));
duke@435:   }
duke@435: 
duke@435:   size_t byte_size() const { return _word_size * sizeof(HeapWord); }
duke@435:   size_t word_size() const { return _word_size; }
duke@435: 
duke@435:   bool is_empty() const { return word_size() == 0; }
coleenp@5614:   void* operator new(size_t size) throw();
coleenp@5614:   void* operator new [](size_t size) throw();
minqi@5103:   void  operator delete(void* p);
minqi@5103:   void  operator delete [](void* p);
duke@435: };
duke@435: 
duke@435: // For iteration over MemRegion's.
duke@435: 
duke@435: class MemRegionClosure : public StackObj {
duke@435: public:
duke@435:   virtual void do_MemRegion(MemRegion mr) = 0;
duke@435: };
duke@435: 
duke@435: // A ResourceObj version of MemRegionClosure
duke@435: 
duke@435: class MemRegionClosureRO: public MemRegionClosure {
duke@435: public:
coleenp@5614:   void* operator new(size_t size, ResourceObj::allocation_type type, MEMFLAGS flags) throw() {
zgu@3900:         return ResourceObj::operator new(size, type, flags);
duke@435:   }
coleenp@5614:   void* operator new(size_t size, Arena *arena) throw() {
duke@435:         return ResourceObj::operator new(size, arena);
duke@435:   }
coleenp@5614:   void* operator new(size_t size) throw() {
duke@435:         return ResourceObj::operator new(size);
duke@435:   }
duke@435: 
duke@435:   void  operator delete(void* p) {} // nothing to do
duke@435: };
stefank@2314: 
stefank@2314: #endif // SHARE_VM_MEMORY_MEMREGION_HPP