1 /*
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 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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24 
25 #ifndef SHARE_OOPS_REFARRAYOOP_HPP
26 #define SHARE_OOPS_REFARRAYOOP_HPP
27 
28 #include "oops/arrayOop.hpp"
29 #include "utilities/align.hpp"
30 #include <type_traits>
31 
32 class Klass;
33 
34 // An refArrayOop is an array containing references (oops).
35 // Evaluating "String arg[10]" will create an refArrayOop.
36 
37 class refArrayOopDesc : public arrayOopDesc {
38   friend class ArchiveHeapWriter;
39   friend class RefArrayKlass;
40   friend class Runtime1;
41   friend class psPromotionManager;
42   friend class CSetMarkWordClosure;
43   friend class Continuation;
44   template <typename T>
45   friend class RawOopWriter;
46 
47   template <class T> T* obj_at_addr(int index) const;
48 
49   template <class T>
50   static ptrdiff_t obj_at_offset(int index) {
51     return base_offset_in_bytes() + sizeof(T) * index;
52   }
53 
54  public:
55   // Returns the offset of the first element.
56   static int base_offset_in_bytes() {
57     return arrayOopDesc::base_offset_in_bytes(T_OBJECT);
58   }
59 
60   inline static refArrayOop cast(oop o);
61 
62   // base is the address following the header.
63   inline HeapWord* base() const;
64 
65   // Accessing
66   oop obj_at(int index) const;
67   oop obj_at(int index, TRAPS) const;
68 
69   void obj_at_put(int index, oop value);
70   void obj_at_put(int index, oop value, TRAPS);
71 
72   oop replace_if_null(int index, oop exchange_value);
73 
74   // Sizing
75   size_t object_size()        { return object_size(length()); }
76 
77   static size_t object_size(int length) {
78     // This returns the object size in HeapWords.
79     size_t asz = (size_t)length * heapOopSize;
80     size_t size_words = heap_word_size(base_offset_in_bytes() + asz);
81     size_t osz = align_object_size(size_words);
82     assert(osz < max_jint, "no overflow");
83     return osz;
84   }
85 
86   Klass* element_klass();
87 
88 public:
89   // special iterators for index ranges, returns size of object
90   template <typename OopClosureType>
91   void oop_iterate_range(OopClosureType* blk, int start, int end);
92 };
93 
94 // See similar requirement for oopDesc.
95 static_assert(std::is_trivially_default_constructible<refArrayOopDesc>::value, "required");
96 
97 #endif // SHARE_OOPS_REFARRAYOOP_HPP