Add R-Tree data structure.
Review URL: https://codereview.appspot.com/6489055
git-svn-id: http://skia.googlecode.com/svn/trunk@5401 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/core/SkBBoxHierarchy.h b/src/core/SkBBoxHierarchy.h
new file mode 100644
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+++ b/src/core/SkBBoxHierarchy.h
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+
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkBBoxHierarchy_DEFINED
+#define SkBBoxHierarchy_DEFINED
+
+#include "SkRect.h"
+#include "SkTDArray.h"
+
+/**
+ * Interface for a spatial data structure that associates user data pointers with axis-aligned
+ * bounding boxes, and allows efficient retrieval of intersections with query rectangles.
+ */
+class SkBBoxHierarchy {
+public:
+ virtual ~SkBBoxHierarchy() { }
+
+ /**
+ * Insert a data pointer and corresponding bounding box
+ * @param data The data pointer, may be NULL
+ * @param bounds The bounding box, should not be empty
+ * @param defer Whether or not it is acceptable to delay insertion of this element (building up
+ * an entire spatial data structure at once is often faster and produces better
+ * structures than repeated inserts) until flushDeferredInserts is called or the first
+ * search.
+ */
+ virtual void insert(void* data, const SkIRect& bounds, bool defer = false) = 0;
+
+ /**
+ * If any insertions have been deferred, this forces them to be inserted
+ */
+ virtual void flushDeferredInserts() = 0;
+
+ /**
+ * Populate 'results' with data pointers corresponding to bounding boxes that intersect 'query'
+ */
+ virtual void search(const SkIRect& query, SkTDArray<void*>* results) = 0;
+
+ virtual void clear() = 0;
+
+ /**
+ * Gets the number of insertions
+ */
+ virtual int getCount() const = 0;
+};
+
+#endif
+