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

1 files changed, 53 insertions, 0 deletions

diff --git a/src/core/SkBBoxHierarchy.h b/src/core/SkBBoxHierarchy.h
new file mode 100644
index 0000000000..347871f87b
--- /dev/null
+++ b/src/core/SkBBoxHierarchy.h
@@ -0,0 +1,53 @@
+
+/*
+ * 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
+