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#include <QtCore/QtDebug>

#include <QtCore/QList>

#include <algorithm>

#include <iterator>

#include <iostream>

#include "compress.h"

#define QLALR_NO_CHECK_SORTED_TABLE

struct _Fit: public std::binary_function<int, int, bool>

{

  inline bool operator () (int a, int b) const

  {

    return a == 0 || b == 0 || a == b;

  }

};

struct _PerfectMatch: public std::binary_function<int, int, bool>

{

  inline bool operator () (int a, int b) const

  { return a == b; }

};

struct _GenerateCheck

{

  QVector<int>::const_iterator iterator;

  int initial;

  _GenerateCheck (QVector<int>::const_iterator it, int i):

    iterator (it),

    initial (i) {}

  inline int operator () ()

  {

    int check = initial++;

    return *iterator++ ? check : -1;

  }

};

class UncompressedRow

{

public:

  typedef const int *const_iterator;

  typedef const int *iterator;

public:

  inline UncompressedRow ():

    _M_index (0),

    _M_begin (0),

    _M_end (0),

    _M_beginNonZeros (0),

    _M_endNonZeros (0) {}

  inline UncompressedRow (int index, const_iterator begin, const_iterator end)

  { assign (index, begin, end); }

  inline int index () const { return _M_index; }

  inline const_iterator begin () const { return _M_begin; }

  inline const_iterator end () const { return _M_end; }

  inline void assign (int index, const_iterator begin, const_iterator end)

  {

    _M_index = index;

    _M_begin = begin;

    _M_end = end;

    _M_beginNonZeros = _M_begin;

    _M_endNonZeros = _M_end;

    for (_M_beginNonZeros = _M_begin; _M_beginNonZeros != _M_end && ! _M_beginNonZeros [0]; ++_M_beginNonZeros)

      /*continue*/ ;

#if 0

    for (_M_endNonZeros = _M_end; _M_endNonZeros != _M_beginNonZeros && ! _M_endNonZeros [-1]; --_M_endNonZeros)

      /*continue*/ ;

#endif

  }

  inline int at (int index) const

  { return _M_begin [index]; }

  inline bool isEmpty () const

  { return _M_begin == _M_end; }

  inline int size () const

  { return _M_end - _M_begin; }

  inline int nonZeroElements () const

  { return _M_endNonZeros - _M_beginNonZeros; }

  inline int count (int value) const

  { return std::count (begin (), end (), value); }

  inline const_iterator beginNonZeros () const

  { return _M_beginNonZeros; }

  inline const_iterator endNonZeros () const

  { return _M_endNonZeros; }

private:

  int _M_index;

  const_iterator _M_begin;

  const_iterator _M_end;

  const_iterator _M_beginNonZeros;

  const_iterator _M_endNonZeros;

};

struct _SortUncompressedRow: public std::binary_function<UncompressedRow, UncompressedRow, bool>

{

  inline bool operator () (const UncompressedRow &a, const UncompressedRow &b) const

  { return a.count (0) > b.count (0); }

};

Compress::Compress ()

{

}

void Compress::operator () (int *table, int row_count, int column_count)

{

  index.clear ();

  info.clear ();

  check.clear ();

  QVector<UncompressedRow> sortedTable (row_count);

  for (int i = 0; i < row_count; ++i)

    {

      int *begin = &table [i * column_count];

      int *end = begin + column_count;

      sortedTable [i].assign (i, begin, end);

    }

  qSort (sortedTable.begin (), sortedTable.end (), _SortUncompressedRow ());

#ifndef QLALR_NO_CHECK_SORTED_TABLE

  int previous_zeros = INT_MAX;

  foreach (UncompressedRow row, sortedTable)

    {

      int zeros = row.count (0);

      Q_ASSERT (zeros <= previous_zeros);

      zeros = previous_zeros;

      qDebug () << "OK!";

    }

#endif

  index.fill (-999999, row_count);

  foreach (UncompressedRow row, sortedTable)

    {

      int first_token = std::distance (row.begin (), row.beginNonZeros ());

      QVector<int>::iterator pos = info.begin ();

      while (pos != info.end ())

        {

          if (pos == info.begin ())

            {

              // try to find a perfect match

              QVector<int>::iterator pm = std::search (pos, info.end (), row.beginNonZeros (), row.endNonZeros (), _PerfectMatch ());

              if (pm != info.end ())

                {

                  pos = pm;

                  break;

                }

            }

          pos = std::search (pos, info.end (), row.beginNonZeros (), row.endNonZeros (), _Fit ());

          if (pos == info.end ())

            break;

          int idx = std::distance (info.begin (), pos) - first_token;

          bool conflict = false;

          for (int j = 0; ! conflict && j < row.size (); ++j)

            {

              if (row.at (j) == 0)

                conflict |= idx + j >= 0 && check [idx + j] == j;

              else

                conflict |= check [idx + j] == j;

            }

          if (! conflict)

            break;

          ++pos;

        }

      if (pos == info.end ())

        {

          int size = info.size ();

          info.resize (info.size () + row.nonZeroElements ());

          check.resize (info.size ());

          std::fill (check.begin () + size, check.end (), -1);

          pos = info.begin () + size;

        }

      int offset = std::distance (info.begin (), pos);

      index [row.index ()] = offset - first_token;

      for (const int *it = row.beginNonZeros (); it != row.endNonZeros (); ++it, ++pos)

        {

          if (*it)

            *pos = *it;

        }

      int i = row.index ();

      for (int j = 0; j < row.size (); ++j)

        {

          if (row.at (j) == 0)

            continue;

          check [index [i] + j] = j;

        }

    }

#if 0

  foreach (UncompressedRow row, sortedTable)

    {

      int i = row.index ();

      Q_ASSERT (i < sortedTable.size ());

      for (int j = 0; j < row.size (); ++j)

        {

          if (row.at (j) == 0)

            {

              Q_ASSERT (index [i] + j < 0 || check [index [i] + j] != j);

              continue;

            }

          Q_ASSERT ( info [index [i] + j] == row.at (j));

          Q_ASSERT (check [index [i] + j] == j);

        }

    }

#endif

}