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_OBJARRAYOOP_HPP
26 #define SHARE_OOPS_OBJARRAYOOP_HPP
27 
28 #include "oops/arrayOop.hpp"
29 #include "utilities/align.hpp"
30 
31 #include <type_traits>
32 
33 class Klass;
34 
35 // An objArrayOop is an array containing oops.
36 // Evaluating "String arg[10]" will create an objArrayOop.
37 
38 class objArrayOopDesc : public arrayOopDesc {
39   friend class ArchiveHeapWriter;
40   friend class ObjArrayKlass;
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   // base is the address following the header.
62   HeapWord* base() const;
63 
64   // Accessing
65   oop obj_at(int index) const;
66 
67   void obj_at_put(int index, oop value);
68 
69   oop replace_if_null(int index, oop exchange_value);
70 
71   // Sizing
72   size_t object_size()        { return object_size(length()); }
73 
74   static size_t object_size(int length) {
75     // This returns the object size in HeapWords.
76     size_t asz = (size_t)length * heapOopSize;
77     size_t size_words = heap_word_size(base_offset_in_bytes() + asz);
78     size_t osz = align_object_size(size_words);
79     assert(osz < max_jint, "no overflow");
80     return osz;
81   }
82 
83   Klass* element_klass();
84 
85 public:
86   // special iterators for index ranges, returns size of object
87   template <typename OopClosureType>
88   void oop_iterate_range(OopClosureType* blk, int start, int end);
89 };
90 
91 // See similar requirement for oopDesc.
92 static_assert(std::is_trivially_default_constructible<objArrayOopDesc>::value, "required");
93 
94 #endif // SHARE_OOPS_OBJARRAYOOP_HPP