/****************************************************************************

**

** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

** All rights reserved.

** Contact: Nokia Corporation (qt-info@nokia.com)

**

** This file is part of the utils of the Qt Toolkit.

**

** $QT_BEGIN_LICENSE:LGPL$

** No Commercial Usage

** This file contains pre-release code and may not be distributed.

** You may use this file in accordance with the terms and conditions

** contained in the Technology Preview License Agreement accompanying

** this package.

**

** GNU Lesser General Public License Usage

** Alternatively, this file may be used under the terms of the GNU Lesser

** General Public License version 2.1 as published by the Free Software

** Foundation and appearing in the file LICENSE.LGPL included in the

** packaging of this file.  Please review the following information to

** ensure the GNU Lesser General Public License version 2.1 requirements

** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.

**

** In addition, as a special exception, Nokia gives you certain additional

** rights.  These rights are described in the Nokia Qt LGPL Exception

** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.

**

** If you have questions regarding the use of this file, please contact

** Nokia at qt-info@nokia.com.

**

**

**

**

**

**

**

**

** $QT_END_LICENSE$

**

****************************************************************************/

#include <QtCore/QtCore>

#include "cppgenerator.h"

#include "lalr.h"

#include "recognizer.h"

QString CppGenerator::copyrightHeader() const

{

  return QLatin1String(

    "/****************************************************************************\n"

    "**\n"

    "** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).\n"

    "** All rights reserved.\n"

    "** Contact: Nokia Corporation (qt-info@nokia.com)\n"

    "**\n"

    "** This file is part of the QtCore module of the Qt Toolkit.\n"

    "**\n"

    "** $QT_BEGIN_LICENSE:LGPL$\n"

    "** No Commercial Usage\n"

    "** This file contains pre-release code and may not be distributed.\n"

    "** You may use this file in accordance with the terms and conditions\n"

    "** contained in the Technology Preview License Agreement accompanying\n"

    "** this package.\n"

    "**\n"

    "** GNU Lesser General Public License Usage\n"

    "** Alternatively, this file may be used under the terms of the GNU Lesser\n"

    "** General Public License version 2.1 as published by the Free Software\n"

    "** Foundation and appearing in the file LICENSE.LGPL included in the\n"

    "** packaging of this file.  Please review the following information to\n"

    "** ensure the GNU Lesser General Public License version 2.1 requirements\n"

    "** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.\n"

    "**\n"

    "** In addition, as a special exception, Nokia gives you certain additional\n"

    "** rights.  These rights are described in the Nokia Qt LGPL Exception\n"

    "** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.\n"

    "**\n"

    "** If you have questions regarding the use of this file, please contact\n"

    "** Nokia at qt-info@nokia.com.\n"

    "**\n"

    "**\n"

    "**\n"

    "**\n"

    "**\n"

    "**\n"

    "**\n"

    "**\n"

    "** $QT_END_LICENSE$\n"

    "**\n"

    "****************************************************************************/\n"

    "\n");

}

QString CppGenerator::privateCopyrightHeader() const

{

  return QLatin1String(

    "//\n"

    "//  W A R N I N G\n"

    "//  -------------\n"

    "//\n"

    "// This file is not part of the Qt API.  It exists for the convenience\n"

    "// of other Qt classes.  This header file may change from version to\n"

    "// version without notice, or even be removed.\n"

    "//\n"

    "// We mean it.\n"

    "//\n");

}

QString CppGenerator::startIncludeGuard(const QString &fileName)

{

    const QString normalized(QString(fileName).replace(QLatin1Char('.'), QLatin1Char('_')).toUpper());

    return QString::fromLatin1("#ifndef %1\n"

                               "#define %2\n").arg(normalized, normalized);

}

QString CppGenerator::endIncludeGuard(const QString &fileName)

{

    const QString normalized(QString(fileName).replace(QLatin1Char('.'), QLatin1Char('_')).toUpper());

    return QString::fromLatin1("#endif // %1\n").arg(normalized);

}

void CppGenerator::operator () ()

{

  // action table...

  state_count = aut.states.size ();

  terminal_count = grammar.terminals.size ();

  non_terminal_count = grammar.non_terminals.size ();

#define ACTION(i, j) table [(i) * terminal_count + (j)]

#define GOTO(i, j) pgoto [(i) * non_terminal_count + (j)]

  int *table = new int [state_count * terminal_count];

  ::memset (table, 0, state_count * terminal_count * sizeof (int));

  int *pgoto = new int [state_count * non_terminal_count];

  ::memset (pgoto, 0, state_count * non_terminal_count * sizeof (int));

  accept_state = -1;

  int shift_reduce_conflict_count = 0;

  int reduce_reduce_conflict_count = 0;

  for (StatePointer state = aut.states.begin (); state != aut.states.end (); ++state)

    {

      int q = aut.id (state);

      for (Bundle::iterator a = state->bundle.begin (); a != state->bundle.end (); ++a)

        {

          int symbol = aut.id (a.key ());

          int r = aut.id (a.value ());

          Q_ASSERT (r < state_count);

          if (grammar.isNonTerminal (a.key ()))

            {

              Q_ASSERT (symbol >= terminal_count && symbol < grammar.names.size ());

              GOTO (q, symbol - terminal_count) = r;

            }

          else

            ACTION (q, symbol) = r;

        }

      for (ItemPointer item = state->closure.begin (); item != state->closure.end (); ++item)

        {

          if (item->dot != item->end_rhs ())

            continue;

          int r = aut.id (item->rule);

          NameSet lookaheads = aut.lookaheads.value (item);

          if (item->rule == grammar.goal)

            accept_state = q;

          foreach (Name s, lookaheads)

            {

              int &u = ACTION (q, aut.id (s));

              if (u == 0)

                u = - r;

              else if (u < 0)

                {

                  if (verbose)

                    qout << "*** Warning. Found a reduce/reduce conflict in state " << q << " on token ``" << s << "'' between rule "

                         << r << " and " << -u << endl;

                  ++reduce_reduce_conflict_count;

                  u = qMax (u, -r);

                  if (verbose)

                    qout << "\tresolved using rule " << -u << endl;

                }

              else if (u > 0)

                {

                  if (item->rule->prec != grammar.names.end() && grammar.token_info.contains (s))

                    {

                      Grammar::TokenInfo info_r = grammar.token_info.value (item->rule->prec);

                      Grammar::TokenInfo info_s = grammar.token_info.value (s);

                      if (info_r.prec > info_s.prec)

                        u = -r;

                      else if (info_r.prec == info_s.prec)

                        {

                          switch (info_r.assoc) {

                          case Grammar::Left:

                            u = -r;

                            break;

                          case Grammar::Right:

                            // shift... nothing to do

                            break;

                          case Grammar::NonAssoc:

                            u = 0;

                            break;

                          } // switch

                        }

                    }

                  else

                    {

                      ++shift_reduce_conflict_count;

                      if (verbose)

                        qout << "*** Warning. Found a shift/reduce conflict in state " << q << " on token ``" << s << "'' with rule " << r << endl;

                    }

                }

            }

        }

    }

  if (shift_reduce_conflict_count || reduce_reduce_conflict_count)

    {

      if (shift_reduce_conflict_count != grammar.expected_shift_reduce

          || reduce_reduce_conflict_count != grammar.expected_reduce_reduce)

        qerr << "*** Conflicts: " << shift_reduce_conflict_count << " shift/reduce, " << reduce_reduce_conflict_count << " reduce/reduce" << endl;

      if (verbose)

        qout << endl << "*** Conflicts: " << shift_reduce_conflict_count << " shift/reduce, " << reduce_reduce_conflict_count << " reduce/reduce" << endl

             << endl;

    }

  QBitArray used_rules (grammar.rules.count ());

  int q = 0;

  for (StatePointer state = aut.states.begin (); state != aut.states.end (); ++state, ++q)

    {

      for (int j = 0; j < terminal_count; ++j)

        {

          int &u = ACTION (q, j);

          if (u < 0)

            used_rules.setBit (-u - 1);

        }

    }

  for (int i = 0; i < used_rules.count (); ++i)

    {

      if (! used_rules.testBit (i))

        {

          RulePointer rule = grammar.rules.begin () + i;

          if (rule != grammar.goal)

            qerr << "*** Warning: Rule ``" << *rule << "'' is useless!" << endl;

        }

    }

  q = 0;

  for (StatePointer state = aut.states.begin (); state != aut.states.end (); ++state, ++q)

    {

      for (int j = 0; j < terminal_count; ++j)

        {

          int &u = ACTION (q, j);

          if (u >= 0)

            continue;

          RulePointer rule = grammar.rules.begin () + (- u - 1);

          if (state->defaultReduce == rule)

            u = 0;

        }

    }

  // ... compress the goto table

  defgoto.resize (non_terminal_count);

  for (int j = 0; j < non_terminal_count; ++j)

    {

      count.fill (0, state_count);

      int &mx = defgoto [j];

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

        {

          int r = GOTO (i, j);

          if (! r)

            continue;

          ++count [r];

          if (count [r] > count [mx])

            mx = r;

        }

    }

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

    {

      for (int j = 0; j < non_terminal_count; ++j)

        {

          int &r = GOTO (i, j);

          if (r == defgoto [j])

            r = 0;

        }

    }

  compressed_action (table, state_count, terminal_count);

  compressed_goto (pgoto, state_count, non_terminal_count);

  delete[] table;

  table = 0;

  delete[] pgoto;

  pgoto = 0;

#undef ACTION

#undef GOTO

  if (! grammar.merged_output.isEmpty())

    {

      QFile f(grammar.merged_output);

      if (! f.open (QFile::WriteOnly))

        {

          fprintf (stderr, "*** cannot create %s\n", qPrintable(grammar.merged_output));

          return;

        }

      QTextStream out (&f);

      out << "// This file was generated by qlalr - DO NOT EDIT!\n";

      if (copyright)

        {

          out << copyrightHeader()

              << privateCopyrightHeader()

              << endl;

        }

      out << startIncludeGuard(grammar.merged_output) << endl;

      generateDecl (out);

      generateImpl (out);

      out << p.decls();

      out << p.impls();

      out << endl;

      out << endIncludeGuard(grammar.merged_output) << endl;

      return;

    }

  // default behaviour

  QString declFileName = grammar.table_name.toLower () + QLatin1String("_p.h");

  QString bitsFileName = grammar.table_name.toLower () + QLatin1String(".cpp");

  { // decls...

    QFile f (declFileName);

    f.open (QFile::WriteOnly);

    QTextStream out (&f);

    out << "// This file was generated by qlalr - DO NOT EDIT!\n";

    QString prot = declFileName.toUpper ().replace (QLatin1Char ('.'), QLatin1Char ('_'));

    if (copyright)

      {

        out << copyrightHeader()

            << privateCopyrightHeader()

            << endl;

      }

    out << "#ifndef " << prot << endl

        << "#define " << prot << endl

        << endl;

    generateDecl (out);

    out << "#endif // " << prot << endl << endl;

  } // end decls

  { // bits...

    QFile f (bitsFileName);

    f.open (QFile::WriteOnly);

    QTextStream out (&f);

    out << "// This file was generated by qlalr - DO NOT EDIT!\n";

    if (copyright)

      out << copyrightHeader();

    out << "#include \"" << declFileName << "\"" << endl << endl;

    generateImpl(out);

  } // end bits

  if (! grammar.decl_file_name.isEmpty ())

    {

      QFile f (grammar.decl_file_name);

      f.open (QFile::WriteOnly);

      QTextStream out (&f);

      out << "// This file was generated by qlalr - DO NOT EDIT!\n";

      out << p.decls();

    }

  if (! grammar.impl_file_name.isEmpty ())

    {

      QFile f (grammar.impl_file_name);

      f.open (QFile::WriteOnly);

      QTextStream out (&f);

      out << "// This file was generated by qlalr - DO NOT EDIT!\n";

      out << p.impls();

    }

}

QString CppGenerator::debugInfoProt() const

{

    QString prot = QLatin1String("QLALR_NO_");

    prot += grammar.table_name.toUpper();

    prot += QLatin1String("_DEBUG_INFO");

    return prot;

}

void CppGenerator::generateDecl (QTextStream &out)

{

  out << "class " << grammar.table_name << endl

      << "{" << endl

      << "public:" << endl

      << "  enum {" << endl;

  foreach (Name t, grammar.terminals)

    {

      QString name = *t;

      int value = std::distance (grammar.names.begin (), t);

      if (name == QLatin1String ("$end"))

        name = QLatin1String ("EOF_SYMBOL");

      else if (name == QLatin1String ("$accept"))

        name = QLatin1String ("ACCEPT_SYMBOL");

      else

        name.prepend (grammar.token_prefix);

      out << "    " << name << " = " << value << "," << endl;

    }

  out << endl

      << "    ACCEPT_STATE = " << accept_state << "," << endl

      << "    RULE_COUNT = " << grammar.rules.size () << "," << endl

      << "    STATE_COUNT = " << state_count << "," << endl

      << "    TERMINAL_COUNT = " << terminal_count << "," << endl

      << "    NON_TERMINAL_COUNT = " << non_terminal_count << "," << endl

      << endl

      << "    GOTO_INDEX_OFFSET = " << compressed_action.index.size () << "," << endl

      << "    GOTO_INFO_OFFSET = " << compressed_action.info.size () << "," << endl

      << "    GOTO_CHECK_OFFSET = " << compressed_action.check.size () << endl

      << "  };" << endl

      << endl

      << "  static const char  *const spell [];" << endl

      << "  static const int            lhs [];" << endl

      << "  static const int            rhs [];" << endl;

  if (debug_info)

    {

      QString prot = debugInfoProt();

      out << endl << "#ifndef " << prot << endl

          << "  static const int     rule_index [];" << endl

          << "  static const int      rule_info [];" << endl

          << "#endif // " << prot << endl << endl;

    }

  out << "  static const int   goto_default [];" << endl

      << "  static const int action_default [];" << endl

      << "  static const int   action_index [];" << endl

      << "  static const int    action_info [];" << endl

      << "  static const int   action_check [];" << endl

      << endl

      << "  static inline int nt_action (int state, int nt)" << endl

      << "  {" << endl

      << "    const int *const goto_index = &action_index [GOTO_INDEX_OFFSET];" << endl

      << "    const int *const goto_check = &action_check [GOTO_CHECK_OFFSET];" << endl

      << endl

      << "    const int yyn = goto_index [state] + nt;" << endl

      << endl

      << "    if (yyn < 0 || goto_check [yyn] != nt)" << endl

      << "      return goto_default [nt];" << endl

      << endl

      << "    const int *const goto_info = &action_info [GOTO_INFO_OFFSET];" << endl

      << "    return goto_info [yyn];" << endl

      << "  }" << endl

      << endl

      << "  static inline int t_action (int state, int token)" << endl

      << "  {" << endl

      << "    const int yyn = action_index [state] + token;" << endl

      << endl

      << "    if (yyn < 0 || action_check [yyn] != token)" << endl

      << "      return - action_default [state];" << endl

      << endl

      << "    return action_info [yyn];" << endl

      << "  }" << endl

      << "};" << endl

      << endl

      << endl;

}

void CppGenerator::generateImpl (QTextStream &out)

{

  int idx = 0;

  out << "const char *const " << grammar.table_name << "::spell [] = {";

  idx = 0;

  QMap<Name, int> name_ids;

  bool first_nt = true;