Safe-browsing PrefixSet cleanups.

chrome/browser/safe_browsing/prefix_set.h

 // Copyright (c) 2011 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.
 //
 // A read-only set implementation for |SBPrefix| items.  Prefixes are
 // sorted and stored as 16-bit deltas from the previous prefix.  An
 // index structure provides quick random access, and also handles
 // cases where 16 bits cannot encode a delta.
 //
 // For example, the sequence {20, 25, 41, 65432, 150000, 160000} would
@@ skipping 54 matching lines @@
 
   // |true| if |prefix| was in |prefixes| passed to the constructor.
   bool Exists(SBPrefix prefix) const;
 
   // Persist the set on disk.
   static PrefixSet* LoadFile(const FilePath& filter_name);
   bool WriteFile(const FilePath& filter_name) const;
 
   // Regenerate the vector of prefixes passed to the constructor into
   // |prefixes|.  Prefixes will be added in sorted order.
-  void GetPrefixes(std::vector<SBPrefix>* prefixes);
+  void GetPrefixes(std::vector<SBPrefix>* prefixes) const;
 
  private:
-  // Maximum delta that can be encoded in a 16-bit unsigned.
-  static const unsigned kMaxDelta = 256 * 256;
-
   // Maximum number of consecutive deltas to encode before generating
   // a new index entry.  This helps keep the worst-case performance
   // for |Exists()| under control.
   static const size_t kMaxRun = 100;
 
   // Helper for |LoadFile()|.  Steals the contents of |index| and
   // |deltas| using |swap()|.
   PrefixSet(std::vector<std::pair<SBPrefix,size_t> > *index,
             std::vector<uint16> *deltas);
 
   // Top-level index of prefix to offset in |deltas_|.  Each pair
   // indicates a base prefix and where the deltas from that prefix
   // begin in |deltas_|.  The deltas for a pair end at the next pair's
   // index into |deltas_|.
   std::vector<std::pair<SBPrefix,size_t> > index_;
 
   // Deltas which are added to the prefix in |index_| to generate
   // prefixes.  Deltas are only valid between consecutive items from
   // |index_|, or the end of |deltas_| for the last |index_| pair.
   std::vector<uint16> deltas_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefixSet);
 };
 
 }  // namespace safe_browsing
 
 #endif  // CHROME_BROWSER_SAFE_BROWSING_PREFIX_SET_H_