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

                          qgsrastercalcparser.yy

             Bison file for raster calculation parser

                          --------------------

    begin                : 2010-10-25

    copyright            : (C) 2010 by Marco Hugentobler

    email                : marco dot hugentobler at sourcepole dot ch

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

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

 *                                                                         *

 *   This program is free software; you can redistribute it and/or modify  *

 *   it under the terms of the GNU General Public License as published by  *

 *   the Free Software Foundation; either version 2 of the License, or     *

 *   (at your option) any later version.                                   *

 *                                                                         *

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

%{

  #include "qgsrastercalcnode.h"

#ifdef _MSC_VER

#  pragma warning( disable: 4065 )  // switch statement contains 'default' but no 'case' labels

#  pragma warning( disable: 4701 )  // Potentially uninitialized local variable 'name' used

#endif

  // don't redeclare malloc/free

  #define YYINCLUDED_STDLIB_H 1

  QgsRasterCalcNode* parseRasterCalcString(const QString& str, QString& parserErrorMsg);

  //! from lex.yy.c

  extern int raster_lex();

  extern char* raster_text;

  extern void set_raster_input_buffer(const char* buffer);

  //! variable where the parser error will be stored

  QString rParserErrorMsg;

  //! sets gParserErrorMsg

  void raster_error(const char* msg);

  //! temporary list for nodes without parent (if parsing fails these nodes are removed)

  QList<QgsRasterCalcNode*> gTmpNodes;

  void joinTmpNodes(QgsRasterCalcNode* parent, QgsRasterCalcNode* left, QgsRasterCalcNode* right);

  void addToTmpNodes(QgsRasterCalcNode* node);

  // we want verbose error messages

  #define YYERROR_VERBOSE 1

%}

%union { QgsRasterCalcNode* node; double number; QgsRasterCalcNode::Operator op;}

%start root

%token RASTER_BAND_REF

%token<number> NUMBER

%token<op> FUNCTION

%token<op> FUNCTION_2_ARGS

%token IF

%type <node> root

%type <node> raster_exp

%left AND

%left OR

%left NE

%left GE

%left LE

%left '=' '<' '>'

%left '+' '-'

%left '*' '/'

%left '^'

%left UMINUS  // fictitious symbol (for unary minus)

%%

root: raster_exp{}

;

raster_exp:

  FUNCTION '(' raster_exp ')'   { $$ = new QgsRasterCalcNode($1, $3, 0); joinTmpNodes($$, $3, 0);}

  | FUNCTION_2_ARGS '(' raster_exp ',' raster_exp ')' { $$ = new QgsRasterCalcNode($1, $3, $5); joinTmpNodes($$, $3, $5);}

  | IF '(' raster_exp ',' raster_exp ',' raster_exp ')' { QVector <QgsRasterCalcNode *> tmpVect;

                                                            tmpVect<< $3<< $5<< $7;

                                                            $$ = new QgsRasterCalcNode("if", tmpVect);

                                                            joinTmpNodes($$, $3, $5);

                                                            gTmpNodes.removeAll($7);

                                                          }

  | raster_exp AND raster_exp   { $$ = new QgsRasterCalcNode( QgsRasterCalcNode::opAND, $1, $3 ); joinTmpNodes($$,$1,$3); }

  | raster_exp OR raster_exp   { $$ = new QgsRasterCalcNode( QgsRasterCalcNode::opOR, $1, $3 ); joinTmpNodes($$,$1,$3); }

  | raster_exp '=' raster_exp   { $$ = new QgsRasterCalcNode( QgsRasterCalcNode::opEQ, $1, $3 ); joinTmpNodes($$,$1,$3); }

  | raster_exp NE raster_exp   { $$ = new QgsRasterCalcNode( QgsRasterCalcNode::opNE, $1, $3 ); joinTmpNodes($$,$1,$3); }

  | raster_exp '>' raster_exp   { $$ = new QgsRasterCalcNode( QgsRasterCalcNode::opGT, $1, $3 ); joinTmpNodes($$, $1, $3); }

  | raster_exp '<' raster_exp   { $$ = new QgsRasterCalcNode( QgsRasterCalcNode::opLT, $1, $3 ); joinTmpNodes($$, $1, $3); }

  | raster_exp GE raster_exp   { $$ = new QgsRasterCalcNode( QgsRasterCalcNode::opGE, $1, $3 ); joinTmpNodes($$, $1, $3); }

  | raster_exp LE raster_exp   { $$ = new QgsRasterCalcNode( QgsRasterCalcNode::opLE, $1, $3 ); joinTmpNodes($$, $1, $3); }

  | raster_exp '^' raster_exp   { $$ = new QgsRasterCalcNode(QgsRasterCalcNode::opPOW, $1, $3); joinTmpNodes($$,$1,$3); }

  | raster_exp '*' raster_exp   { $$ = new QgsRasterCalcNode(QgsRasterCalcNode::opMUL, $1, $3); joinTmpNodes($$,$1,$3); }

  | raster_exp '/' raster_exp   { $$ = new QgsRasterCalcNode(QgsRasterCalcNode::opDIV, $1, $3); joinTmpNodes($$,$1,$3); }

  | raster_exp '+' raster_exp   { $$ = new QgsRasterCalcNode(QgsRasterCalcNode::opPLUS, $1, $3); joinTmpNodes($$,$1,$3); }

  | raster_exp '-' raster_exp   { $$ = new QgsRasterCalcNode(QgsRasterCalcNode::opMINUS, $1, $3); joinTmpNodes($$,$1,$3); }

  | '(' raster_exp ')'          { $$ = $2; }

  | '+' raster_exp %prec UMINUS { $$ = $2; }

  | '-' raster_exp %prec UMINUS { $$ = new QgsRasterCalcNode( QgsRasterCalcNode::opSIGN, $2, 0 ); joinTmpNodes($$, $2, 0); }

  | NUMBER { $$ = new QgsRasterCalcNode($1); addToTmpNodes($$); }

  | RASTER_BAND_REF { $$ = new QgsRasterCalcNode(QString::fromUtf8(raster_text)); addToTmpNodes($$); }

;

%%

void addToTmpNodes(QgsRasterCalcNode* node)

{

  gTmpNodes.append(node);

}

void joinTmpNodes(QgsRasterCalcNode* parent, QgsRasterCalcNode* left, QgsRasterCalcNode* right)

{

  bool res;

  Q_UNUSED(res)

  if (left)

  {

    res = gTmpNodes.removeAll(left) != 0;

    Q_ASSERT(res);

  }

  if (right)

  {

    res = gTmpNodes.removeAll(right) != 0;

    Q_ASSERT(res);

  }

  gTmpNodes.append(parent);

}

QgsRasterCalcNode* localParseRasterCalcString(const QString& str, QString& parserErrorMsg)

{

  // list should be empty when starting

  Q_ASSERT(gTmpNodes.count() == 0);

  set_raster_input_buffer(str.toUtf8().constData());

  int res = raster_parse();

  // list should be empty when parsing was OK

  if (res == 0) // success?

  {

    Q_ASSERT(gTmpNodes.count() == 1);

    return gTmpNodes.takeFirst();

  }

  else // error?

  {

    parserErrorMsg = rParserErrorMsg;

    // remove nodes without parents - to prevent memory leaks

    while (gTmpNodes.size() > 0)

      delete gTmpNodes.takeFirst();

    return nullptr;

  }

}

void raster_error(const char* msg)

{

  rParserErrorMsg = msg;

}