source: code/trunk/src/util/ExprParser.cc @ 1888

/*
 *   ORXONOX - the hottest 3D action shooter ever to exist
 *                    > www.orxonox.net <
 *
 *
 *   License notice:
 *
 *   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.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 *   Author:
 *      Reto Grieder
 *   Co-authors:
 *      ...
 *
 */

/**
  @file
  @brief Declaration of FloatParser
*/

#include "ExprParser.h"
#include <cmath>
#include <cstring>
#include <stdlib.h>

// macros for easier if, else statements
#define CASE_1(var) if (!strcmp(SWITCH,var))
#define CASE(var) else if (!strcmp(SWITCH,var))
#define CASE_ELSE else

//! skip white spaces
#define PARSE_BLANKS while (*reading_stream == ' ') ++reading_stream;

ExprParser::ExprParser(const std::string& str)
{
  this->failed_ = false;
  this->reading_stream = str.c_str();
  if (str.size() == 0 || *reading_stream == '\0')
  {
    this->failed_ = true;
    this->result_ = 0.0;
  }
  else
  {
    this->result_ = parse_expr_8();
    this->remains_ = reading_stream;
  }
}

//Private functions:
/******************/
double ExprParser::parse_argument()
{
   double value = parse_expr_8();
   if (*reading_stream == ',')
   {
      ++reading_stream;
      return value;
   }
   else
   {
     this->failed_ = true;
     return 0;
   }
}

double ExprParser::parse_last_argument()
{
   double value = parse_expr_8();
   if (*reading_stream == ')')
   {
      ++reading_stream;
      return value;
   }
   else
   {
     this->failed_ = true;
     return 0;
   }
}

double ExprParser::parse_expr_8()
{
   double value = parse_expr_7();
   for(;;)
   {
      switch (op)
      {
         case oder:
            value = parse_expr_7() || value;
            break;
         default: return value;
      }
   };
}


double ExprParser::parse_expr_7()
{
   double value = parse_expr_6();
   for(;;)
   {
      switch (op)
      {
         case und:
            value = value && parse_expr_6();
            break;
         default: return value;
      }
   };
}

double ExprParser::parse_expr_6()
{
   double value = parse_expr_5();
   for(;;)
   {
      switch (op)
      {
         case gleich:
            value = (value == parse_expr_5());
            break;
         case ungleich:
            value = (value != parse_expr_5());
            break;
         default:
            return value;
      }
   };
}

double ExprParser::parse_expr_5()
{
   double value = parse_expr_4();
   for(;;)
   {
      switch (op)
      {
         case kleiner:
            value = (value < parse_expr_4());
            break;
         case kleinergleich:
            value = (value <= parse_expr_4());
            break;
         case groesser:
            value = (value > parse_expr_4());
            break;
         case groessergleich:
            value = (value >= parse_expr_4());
            break;
         default:
            return value;
      }
   };
}

double ExprParser::parse_expr_4()
{
   double value = parse_expr_3();
   for(;;)
   {
      switch (op)
      {
         case b_plus:
            value += parse_expr_3();
            break;
         case b_minus:
            value -= parse_expr_3();
            break;
         default:
            return value;
      }
   };
}

double ExprParser::parse_expr_3()
{
   double value = parse_expr_2();
   for(;;)
   {
      switch (op)
      {
         case mal:
            value *= parse_expr_2();
            break;
         case durch:
            value /= parse_expr_2();
            break;
         case modulo:
         {
            double temp = parse_expr_2();
            value = value - floor(value/temp)*temp;
            break;
         }
         default:
            return value;
      }
   };
}

double ExprParser::parse_expr_2()
{
   double value = parse_expr_1();
   while (*reading_stream != '\0')
   {
      op = parse_binary_operator();
      switch (op)
      {
         case hoch:
            value = pow(value,parse_expr_1());
            break;
         default:
            return value;
      }
   };
   op = undef;
   return value;
}

double ExprParser::parse_expr_1()
{
   PARSE_BLANKS
   double value;

   unary_operator op = parse_unary_operator();
   PARSE_BLANKS

   if (*reading_stream == '\0')
   {
     // end of string
     this->failed_ = true;
     return 0;
   }
   else if (*reading_stream > 47 && *reading_stream < 59 || *reading_stream == 46)
   {  // number
      value = strtod(reading_stream, const_cast<char**>(&reading_stream));
   }
   else if (*reading_stream > 64 && *reading_stream < 91 || *reading_stream > 96 && *reading_stream < 123 || *reading_stream == 46)
   {  // variable or function
      char* word = new char[256];
      parse_word(word);
      PARSE_BLANKS
      if (*reading_stream == '(')
      {
         ++reading_stream;
#define SWITCH word
         CASE_1("sin")
            value = sin(parse_last_argument());
         CASE("asin")
            value = asin(parse_last_argument());
         CASE("sinh")
            value = sinh(parse_last_argument());
         CASE("asinh")
         {
            value = parse_last_argument();
            value = log(sqrt(pow(value, 2) + 1) + value);
         }
         CASE("cos")
            value = cos(parse_last_argument());
         CASE("acos")
            value = acos(parse_last_argument());
         CASE("cosh")
            value = cosh(parse_last_argument());
         CASE("acosh")
         {
            value = parse_last_argument();
            value = log(sqrt(pow(value, 2) - 1) + value);
         }
         CASE("tan")
            value = tan(parse_last_argument());
         CASE("atan")
            value = atan(parse_last_argument());
         CASE("atan2")
            value = atan2(parse_argument(),parse_last_argument());
         CASE("tanh")
            value = tanh(parse_last_argument());
         CASE("atanh")
         {
            value = parse_last_argument();
            value = 0.5*log((value + 1)/(value - 1));
         }
         CASE("int")
            value = floor(parse_last_argument());
         CASE("floor")
            value = floor(parse_last_argument());
         CASE("ceil")
            value = ceil(parse_last_argument());
         CASE("abs")
            value = fabs(parse_last_argument());
         CASE("exp")
            value = exp(parse_last_argument());
         CASE("log")
            value = log10(parse_last_argument());
         CASE("ln")
            value = log(parse_last_argument());
         CASE("sign")
         {
            value = parse_last_argument();
            value = (value>0 ? 1 : (value<0 ? -1 : 0));
         }
         CASE("sqrt")
            value = sqrt(parse_last_argument());
         CASE("degrees")
            value = parse_last_argument()*180/3.1415926535897932;
         CASE("radians")
            value = parse_last_argument()*3.1415926535897932/180;
         CASE("mod")
         {
            value = parse_argument();
            double value2 = parse_last_argument();
            value = value - floor(value/value2)*value2;
         }
         CASE("pow")
            value = pow(parse_argument(),parse_last_argument());
         CASE("div")
            value = floor(parse_argument()/parse_last_argument());
         CASE("max")
           value = std::max(parse_argument(),parse_last_argument());
         CASE("min")
           value = std::min(parse_argument(),parse_last_argument());
         CASE_ELSE
         {
           this->failed_ = true;
           delete[] word;
           return 0;
         }
      }
      else
      {
#define SWITCH word
         CASE_1("pi")
           value = 3.1415926535897932;
         CASE("e")
           value = 2.7182818284590452;
         CASE_ELSE
         {
           this->failed_ = true;
           delete[] word;
           return 0;
         }
      }
      delete[] word;
   }
   else if (*reading_stream == 40)
   {  // expresion in paranthesis
      ++reading_stream;
      value = parse_last_argument();
   }
   else
   {
     this->failed_ = true;
     return 0;
   }

   PARSE_BLANKS
   switch (op)
   {
      case u_nicht: return !value;
      case u_plus:  return  value;
      case u_minus: return -value;
      default:
        {
          this->failed_ = true;
          return 0;
        }
   }
}

char* ExprParser::parse_word(char* str)
{
   char* word = str;
   int counter = 0;
   while (*reading_stream > 47 && *reading_stream < 58 || *reading_stream > 64 && *reading_stream < 91 || *reading_stream > 96 && *reading_stream < 123 || *reading_stream == 46)
   {
      *word++ = *reading_stream++;
      counter++;
      if (counter > 255)
      {
        this->failed_ = true;
        return '\0';
      }
   };
   *word = '\0';
   return str;
}

ExprParser::binary_operator ExprParser::parse_binary_operator()
{
   binary_operator op;
   switch (*reading_stream)
   {
      case '+': op = b_plus; break;
      case '-': op = b_minus; break;
      case '*': op = mal; break;
      case '/': op = durch; break;
      case '^': op = hoch; break;
      case '%': op = modulo; break;
      case '&': op = und; break;
      case '|': op = oder; break;
      case '=': op = gleich; break;
      case '!': op = b_nicht; break;
      case '<': op = kleiner; break;
      case '>': op = groesser; break;
      default: return undef;
   }
   if (*++reading_stream == '=')
   {
      if (op > 9)
      {
         ++reading_stream;
         return (binary_operator)(op + 3);
      }
      else
      {
         --reading_stream;
         return undef;
      }
   }
   else
      return op;
}

ExprParser::unary_operator ExprParser::parse_unary_operator()
{
   switch (*reading_stream)
   {
      case '!':
         ++reading_stream;
         return u_nicht;
      case '+':
         ++reading_stream;
         return u_plus;
      case '-':
         ++reading_stream;
         return u_minus;
      default :
         return u_plus;
   }
}