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// Copyright 2009 Martin C. Frith

// A "subset seed" covers a range of sequence.  The size of this range
// is called its span.  At each position, it maps letters (encoded as
// numbers) to subsets of the letters (encoded as numbers).  The
// mapping may or may not be different at different positions.

// Subset seeds are described in:
// G Kucherov et al. J Bioinform Comput Biol. 2006 4(2):553-69.

// "Cyclic" means that the seed can cover arbitrary-size ranges, by
// cyclically repeating.

// The INPUT/OUTPUT FORMAT looks like this:
//   A C G T
//   AG CT
//   ACGT
// Each line represents one position, and each letter-group (separated
// by whitespace) is one subset.  In each position, any letters not
// specified will get mapped to the special DELIMITER subset.  Blank
// lines and comment lines starting with # are ignored.

// The input format is always case-insensitive.  If the
// isMaskLowercase argument of the reading routines is true, then all
// lowercase letters will get mapped to the DELIMITER subset,
// otherwise they will be treated like their uppercase equivalents.


#include <string>
#include <vector>
#include <iosfwd>

namespace cbrc{

class CyclicSubsetSeed{
  typedef unsigned char uchar;

  enum { MAX_LETTERS = 64 };
  enum { DELIMITER = 255 };

  static const char* proteinSeed;

  void fromFile( const std::string& fileName,
             bool isMaskLowercase, const uchar letterCode[] );

  void fromString( const std::string& s,
               bool isMaskLowercase, const uchar letterCode[] );

  void fromStream( std::istream& stream,
               bool isMaskLowercase, const uchar letterCode[] );

  // Every "1" in the spaced seed is a must-match position.  Every "0"
  // (actually, every non-1) is a don't care position.
  void fromSpacedSeed( const std::string& spacedSeed,
                   const std::string& letters,
                   bool isMaskLowercase, const uchar letterCode[] );

  void appendPosition( std::istream& inputLine,
                   bool isMaskLowercase, const uchar letterCode[] );

  void writePosition( std::ostream& out, unsigned position ) const;

  unsigned span() const{
    return subsetLists.size();

  const uchar* subsetMap( unsigned depth ) const{
    return &subsetMaps[0] + (depth % span()) * MAX_LETTERS;

  unsigned subsetCount( unsigned depth ) const{
    return subsetLists[ depth % span() ].size();

  const uchar* firstMap() const{
    return &subsetMaps[0];

  const uchar* nextMap( const uchar* x ) const{
    const uchar* y = x + MAX_LETTERS;
    if( y == &subsetMaps[0] + subsetMaps.size() )
      y = &subsetMaps[0];
    return y;

  std::vector< std::vector<std::string> > subsetLists;
  std::vector<uchar> subsetMaps;

  static void addLetter( std::vector<uchar>& numbersToSubsets,
                   uchar letter, uchar subsetNum,
                   const uchar letterCode[] );

}  // end namespace

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