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src/hotspot/share/oops/arrayOop.hpp

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rev 50331 : 8198285: More consistent Access API for arraycopy


  71 
  72  public:
  73   // The _length field is not declared in C++.  It is allocated after the
  74   // declared nonstatic fields in arrayOopDesc if not compressed, otherwise
  75   // it occupies the second half of the _klass field in oopDesc.
  76   static int length_offset_in_bytes() {
  77     return UseCompressedClassPointers ? klass_gap_offset_in_bytes() :
  78                                sizeof(arrayOopDesc);
  79   }
  80 
  81   // Returns the offset of the first element.
  82   static int base_offset_in_bytes(BasicType type) {
  83     return header_size(type) * HeapWordSize;
  84   }
  85 
  86   // Returns the address of the first element. The elements in the array will not
  87   // relocate from this address until a subsequent thread transition.
  88   inline void* base(BasicType type) const;
  89   inline void* base_raw(BasicType type) const; // GC barrier invariant
  90 












  91   // Tells whether index is within bounds.
  92   bool is_within_bounds(int index) const        { return 0 <= index && index < length(); }
  93 
  94   // Accessors for instance variable which is not a C++ declared nonstatic
  95   // field.
  96   int length() const {
  97     return *(int*)(((intptr_t)this) + length_offset_in_bytes());
  98   }
  99   void set_length(int length) {
 100     *(int*)(((intptr_t)this) + length_offset_in_bytes()) = length;
 101   }
 102 
 103   // Should only be called with constants as argument
 104   // (will not constant fold otherwise)
 105   // Returns the header size in words aligned to the requirements of the
 106   // array object type.
 107   static int header_size(BasicType type) {
 108     size_t typesize_in_bytes = header_size_in_bytes();
 109     return (int)(element_type_should_be_aligned(type)
 110       ? align_object_offset(typesize_in_bytes/HeapWordSize)




  71 
  72  public:
  73   // The _length field is not declared in C++.  It is allocated after the
  74   // declared nonstatic fields in arrayOopDesc if not compressed, otherwise
  75   // it occupies the second half of the _klass field in oopDesc.
  76   static int length_offset_in_bytes() {
  77     return UseCompressedClassPointers ? klass_gap_offset_in_bytes() :
  78                                sizeof(arrayOopDesc);
  79   }
  80 
  81   // Returns the offset of the first element.
  82   static int base_offset_in_bytes(BasicType type) {
  83     return header_size(type) * HeapWordSize;
  84   }
  85 
  86   // Returns the address of the first element. The elements in the array will not
  87   // relocate from this address until a subsequent thread transition.
  88   inline void* base(BasicType type) const;
  89   inline void* base_raw(BasicType type) const; // GC barrier invariant
  90 
  91   template <typename T>
  92   static T* obj_offset_to_raw(arrayOop obj, size_t offset_in_bytes, T* raw) {
  93     if (obj != NULL) {
  94       assert(raw == NULL, "either raw or in-heap");
  95       char* base = reinterpret_cast<char*>((void*) obj);
  96       raw = reinterpret_cast<T*>(base + offset_in_bytes);
  97     } else {
  98       assert(raw != NULL, "either raw or in-heap");
  99     }
 100     return raw;
 101   }
 102 
 103   // Tells whether index is within bounds.
 104   bool is_within_bounds(int index) const        { return 0 <= index && index < length(); }
 105 
 106   // Accessors for instance variable which is not a C++ declared nonstatic
 107   // field.
 108   int length() const {
 109     return *(int*)(((intptr_t)this) + length_offset_in_bytes());
 110   }
 111   void set_length(int length) {
 112     *(int*)(((intptr_t)this) + length_offset_in_bytes()) = length;
 113   }
 114 
 115   // Should only be called with constants as argument
 116   // (will not constant fold otherwise)
 117   // Returns the header size in words aligned to the requirements of the
 118   // array object type.
 119   static int header_size(BasicType type) {
 120     size_t typesize_in_bytes = header_size_in_bytes();
 121     return (int)(element_type_should_be_aligned(type)
 122       ? align_object_offset(typesize_in_bytes/HeapWordSize)


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