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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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class HeapRegion;

class HeapRegionClosure;

class HeapRegionSeq: public CHeapObj {

  // _regions is kept sorted by start address order, and no two regions are

  // overlapping.

  GrowableArray<HeapRegion*> _regions;

  // The index in "_regions" at which to start the next allocation search.

  // (For efficiency only; private to obj_allocate after initialization.)

  int _alloc_search_start;

  // Attempts to allocate a block of the (assumed humongous) word_size,

  // starting at the region "ind".

  HeapWord* alloc_obj_from_region_index(int ind, size_t word_size);

  // Currently, we're choosing collection sets in a round-robin fashion,

  // starting here.

  int _next_rr_candidate;

  // The bottom address of the bottom-most region, or else NULL if there

  // are no regions in the sequence.

  char* _seq_bottom;

 public:

  // Initializes "this" to the empty sequence of regions.

  HeapRegionSeq(const size_t max_size);

  // Adds "hr" to "this" sequence.  Requires "hr" not to overlap with

  // any region already in "this".  (Will perform better if regions are

  // inserted in ascending address order.)

  void insert(HeapRegion* hr);

  // Given a HeapRegion*, returns its index within _regions,

  // or returns -1 if not found.

  int find(HeapRegion* hr);

  // Requires the index to be valid, and return the region at the index.

  HeapRegion* at(size_t i) { return _regions.at((int)i); }

  // Return the number of regions in the sequence.

  size_t length();

  // Returns the number of contiguous regions at the end of the sequence

  // that are available for allocation.

  size_t free_suffix();

  // Requires "word_size" to be humongous (in the technical sense).  If

  // possible, allocates a contiguous subsequence of the heap regions to

  // satisfy the allocation, and returns the address of the beginning of

  // that sequence, otherwise returns NULL.

  HeapWord* obj_allocate(size_t word_size);

  // Apply the "doHeapRegion" method of "blk" to all regions in "this",

  // in address order, terminating the iteration early

  // if the "doHeapRegion" method returns "true".

  void iterate(HeapRegionClosure* blk);

  // Apply the "doHeapRegion" method of "blk" to all regions in "this",

  // starting at "r" (or first region, if "r" is NULL), in a circular

  // manner, terminating the iteration early if the "doHeapRegion" method

  // returns "true".

  void iterate_from(HeapRegion* r, HeapRegionClosure* blk);

  // As above, but start from a given index in the sequence

  // instead of a given heap region.

  void iterate_from(int idx, HeapRegionClosure* blk);

  // Requires "shrink_bytes" to be a multiple of the page size and heap

  // region granularity.  Deletes as many "rightmost" completely free heap

  // regions from the sequence as comprise shrink_bytes bytes.  Returns the

  // MemRegion indicating the region those regions comprised, and sets

  // "num_regions_deleted" to the number of regions deleted.

  MemRegion shrink_by(size_t shrink_bytes, size_t& num_regions_deleted);

  // If "addr" falls within a region in the sequence, return that region,

  // or else NULL.

  HeapRegion* addr_to_region(const void* addr);

  void print();

  // Prints out runs of empty regions.

  void print_empty_runs();

};