Added comments. Hooray!

1 files changed, 17 insertions, 0 deletions

diff --git a/extractor/suffix_array.h b/extractor/suffix_array.h
index 7a4f1110..bf731d79 100644
--- a/extractor/suffix_array.h
+++ b/extractor/suffix_array.h
@@ -17,18 +17,26 @@ class PhraseLocation;
 
 class SuffixArray {
  public:
+  // Creates a suffix array from a data array.
   SuffixArray(shared_ptr<DataArray> data_array);
 
   virtual ~SuffixArray();
 
+  // Returns the size of the suffix array.
   virtual int GetSize() const;
 
+  // Returns the data array on top of which the suffix array is constructed.
   virtual shared_ptr<DataArray> GetData() const;
 
+  // Constructs the longest-common-prefix array using the algorithm of Kasai et
+  // al. (2001).
   virtual vector<int> BuildLCPArray() const;
 
+  // Returns the i-th suffix.
   virtual int GetSuffix(int rank) const;
 
+  // Given the range in which a phrase is located and the next word, returns the
+  // range corresponding to the phrase extended with the next word.
   virtual PhraseLocation Lookup(int low, int high, const string& word,
                                 int offset) const;
 
@@ -38,14 +46,23 @@ class SuffixArray {
   SuffixArray();
 
  private:
+  // Constructs the suffix array using the algorithm of Larsson and Sadakane
+  // (1999).
   void BuildSuffixArray();
 
+  // Bucket sort on the data array (used for initializing the construction of
+  // the suffix array.)
   void InitialBucketSort(vector<int>& groups);
 
   void TernaryQuicksort(int left, int right, int step, vector<int>& groups);
 
+  // Constructs the suffix array in log(n) steps by doubling the length of the
+  // suffixes at each step.
   void PrefixDoublingSort(vector<int>& groups);
 
+  // Given a [low, high) range in the suffix array in which all elements have
+  // the first offset-1 values the same, it returns the first position where the
+  // offset value is greater or equal to word_id.
   int LookupRangeStart(int low, int high, int word_id, int offset) const;
 
   shared_ptr<DataArray> data_array;