1 /*
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 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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 
31 #include <type_traits>
32 
33 class Klass;
34 
35 // An refArrayOop is an array containing references (oops).
36 // Evaluating "String arg[10]" will create an refArrayOop.
37 
38 class refArrayOopDesc : public arrayOopDesc {
39   friend class ArchiveHeapWriter;
40   friend class RefArrayKlass;
41   friend class Runtime1;
42   friend class psPromotionManager;
43   friend class CSetMarkWordClosure;
44   friend class Continuation;
45   template <typename T>
46   friend class RawOopWriter;
47 
48   template <class T> T* obj_at_addr(int index) const;
49 
50   template <class T>
51   static ptrdiff_t obj_at_offset(int index) {
52     return base_offset_in_bytes() + sizeof(T) * index;
53   }
54 
55  public:
56   // Returns the offset of the first element.
57   static int base_offset_in_bytes() {
58     return arrayOopDesc::base_offset_in_bytes(T_OBJECT);
59   }
60 
61   inline static refArrayOop cast(oop o);
62 
63   // base is the address following the header.
64   inline HeapWord* base() const;
65 
66   // Accessing
67   oop obj_at(int index) const;
68   oop obj_at(int index, TRAPS) const;
69 
70   void obj_at_put(int index, oop value);
71   void obj_at_put(int index, oop value, TRAPS);
72 
73   oop replace_if_null(int index, oop exchange_value);
74 
75   // Sizing
76   size_t object_size()        { return object_size(length()); }
77 
78   static size_t object_size(int length) {
79     // This returns the object size in HeapWords.
80     size_t asz = (size_t)length * heapOopSize;
81     size_t size_words = heap_word_size(base_offset_in_bytes() + asz);
82     size_t osz = align_object_size(size_words);
83     assert(osz < max_jint, "no overflow");
84     return osz;
85   }
86 
87   Klass* element_klass();
88 
89 public:
90   // special iterators for index ranges, returns size of object
91   template <typename OopClosureType>
92   void oop_iterate_range(OopClosureType* blk, int start, int end);
93 };
94 
95 // See similar requirement for oopDesc.
96 static_assert(std::is_trivially_default_constructible<refArrayOopDesc>::value, "required");
97 
98 #endif // SHARE_OOPS_REFARRAYOOP_HPP