Improve linearized pdf load/show time.

pdf/range_set.h

Index: pdf/range_set.h
diff --git a/pdf/range_set.h b/pdf/range_set.h
new file mode 100644
index 0000000000000000000000000000000000000000..b615999285a5ac72d4e81b8b91cc8357e0fb20e7
--- /dev/null
+++ b/pdf/range_set.h
@@ -0,0 +1,77 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Defines a set of geometric ranges, and standard operations on it.
+
+#ifndef PDF_RANGE_SET_H_
+#define PDF_RANGE_SET_H_
+
+#include <ostream>
+#include <set>
+#include <string>
+
+#include "ui/gfx/range/range.h"
+
+namespace chrome_pdf {
+
+class RangeSet {
+ public:
+  RangeSet();
+  explicit RangeSet(const gfx::Range& range);
+  ~RangeSet();
+
+  RangeSet(const RangeSet& range_set);
+  RangeSet(RangeSet&& range_set);
+  RangeSet& operator=(const RangeSet& other);
+
+  bool operator==(const RangeSet& other) const;
+  bool operator!=(const RangeSet& other) const;
+
+  bool Contains(uint32_t point) const;
+  bool Contains(const gfx::Range& range) const;
+  bool Contains(const RangeSet& range_set) const;
+
+  bool Intersects(const gfx::Range& range) const;
+  bool Intersects(const RangeSet& range_set) const;
+
+  void Union(const gfx::Range& range);
+  void Union(const RangeSet& range_set);
+
+  void Intersect(const gfx::Range& range);
+  void Intersect(const RangeSet& range_set);
+
+  void Subtract(const gfx::Range& range);
+  void Subtract(const RangeSet& range_set);
+
+  void Xor(const gfx::Range& range);
+  void Xor(const RangeSet& range_set);
+
+  bool IsEmpty() const;
+  void Clear();
+
+  gfx::Range First() const;
+  gfx::Range Last() const;
+  std::string ToString() const;
+
+  struct range_compare {
+    bool operator()(const gfx::Range& lval, const gfx::Range& rval) const {
+      return lval.start() < rval.start();
+    }
+  };
+
+  using RangesContainer = std::set<gfx::Range, range_compare>;
+
+  const RangesContainer& ranges() const { return ranges_; }
+  size_t Size() const { return ranges_.size(); }
+
+ private:
+  RangesContainer ranges_;
+};
+
+}  // namespace chrome_pdf
+
+std::ostream& operator<<(std::ostream& os,
+                         const chrome_pdf::RangeSet& range_set);
+
+#endif  // PDF_RANGE_SET_H_