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..39ef29f74478395c23f205ca93e4fe68555b2de9
--- /dev/null
+++ b/pdf/range_set.h
@@ -0,0 +1,77 @@
+// Copyright (c) 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;
+
+  void Union(const gfx::Range& range);

[Lei Zhang, 2016/10/21 09:33:10]

Put this with the other RangeSet modifiers.

[snake, 2016/10/21 15:13:15]

What do you mean?

[Lei Zhang, 2016/10/25 06:01:49]

What I mean is, you have Contains() and Intersects(), which are const methods,
and then you have non-const methods like Union(), Intersect(), Subtract() and
Xor(). Union() is alone by itself, but it would make more sense to group it
together with Intersect() and friends.

[snake, 2016/10/25 13:57:34]

Done.

+  void Union(const RangeSet& range_set);
+
+  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 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);

[Lei Zhang, 2016/10/21 09:33:10]

Is this ever going to get used in anything but unit tests? Can we omit it?

[snake, 2016/10/21 15:13:15]

I want to use it in my next CLs. Also, it is part of standard operations on
mathematical set.

[Lei Zhang, 2016/10/25 06:01:49]

Ok, got it. If you are going to use it soon, then sure.

+  void Xor(const RangeSet& range_set);
+
+  bool IsEmpty() const;
+  void Clear();
+
+  gfx::Range First() const;
+  gfx::Range Last() const;
+  std::string ToString() const;

[Lei Zhang, 2016/10/21 09:33:10]

Are ToString() and operator<< only used in one unit test file? If yes, move them
into that file?

[snake, 2016/10/21 15:13:15]

It will be used in other unit test files.

+
+  struct range_compare {
+    bool operator()(const gfx::Range& lval, const gfx::Range& rval) const {
+      return lval.start() < rval.start();
+    }
+  };
+
+  typedef std::set<gfx::Range, range_compare> RangesContainer;

[Lei Zhang, 2016/10/21 09:33:10]

not: using foo = bar, instead of typedef bar foo.

[snake, 2016/10/21 15:13:15]

Done.

+
+  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_