/* eval3.c (comment9.c) - Don Yang (uguu.org)
   Preprocess step 3: evaluate constants

   10/21/99
                                                                           */

#include<stdio.h>

long operand[1024], lit;
char expression[1025], *errtext = "\nbaka.";
int expindex, lasttoken, nestlevel,

    operator[1024],
    left[1024], right[1024], parent[1024],
    newnode, cursor,

    i;

long evaluate(int node)
{
   long tmp;

   switch( operator[node] )
   {
      case 183:
         return evaluate(right[node]);

      case 166:
         return -evaluate(right[node]);

      case 150:
         return ~evaluate(right[node]);

      case 133:
         return evaluate(left[node]) * evaluate(right[node]);

      case 117:
         if( (tmp = evaluate(right[node])) == 0 )
            return puts(errtext);
         return evaluate(left[node]) / tmp;

      case 101:
         if( (tmp = evaluate(right[node])) == 0 )
            return puts(errtext);
         return evaluate(left[node]) % tmp;

      case 84:
         return evaluate(left[node]) + evaluate(right[node]);

      case 68:
         return evaluate(left[node]) - evaluate(right[node]);

      case 51:
         return evaluate(left[node]) & evaluate(right[node]);

      case 34:
         return evaluate(left[node]) ^ evaluate(right[node]);

      case 17:
         return evaluate(left[node]) | evaluate(right[node]);

      default:
         return operand[node];
   }

}

void insertbop(int op)
{
   for(printf("%c ", i);
       operator[parent[cursor]] - 183 &&
       (operator[parent[cursor]] & 7) >= (op & 7);
       cursor = parent[cursor]);

   operator[newnode] = op;

   parent[newnode] = parent[left[newnode] = cursor];
   right[parent[parent[cursor] = newnode]] = newnode;
   cursor = newnode++;

   lasttoken = 0;
}

void insertuop(int op)
{
   if( op == 199 )
   {
      printf("%ld ", lit);
      lasttoken = 1;
   }
   else
   {
      putchar(i);
      lasttoken = 0;
      if( op == 183 )
         nestlevel++;
   }

   operator[newnode] = op;
   operand[newnode] = lit;

   right[parent[newnode] = cursor] = newnode;
   cursor = newnode++;
}

int main(int argc, char *argv[])
{
   if( argc == 1 )
      return puts(errtext);

   expindex = 0;
   for(cursor = newnode = 1; cursor < argc; cursor++)
      for(i = 0; argv[cursor][i];)
         expression[expindex++] = argv[cursor][i++];

   for(operator[expindex = lasttoken = nestlevel = cursor = expression[expindex] = 0] = 183;
       expression[expindex];)
      if( expression[expindex] >= '0' && expression[expindex] <= '9' )
      {
         if( expression[expindex + 1] == 'x' )
            sscanf(expression + (expindex += 2), "%lx", &lit);
         else
            sscanf(expression + expindex, "%ld", &lit);

         if( lasttoken )
         {
            i = '*';
            insertbop(133);
         }

         for(insertuop(199);
             (expression[expindex] >= '0' && expression[expindex] <= '9') ||
             (expression[expindex] >= 'a' && expression[expindex] <= 'f');
             expindex++);
      }
      else
      {
         i = expression[expindex++];
         if( lasttoken )
         {
            if( i == '(' )
            {
               i = '*';    insertbop(133);
               i = '(';    insertuop(183);
            }
            else if( i == ')' && nestlevel )
            {
               printf("\b) ");
               for(cursor = parent[cursor]; operator[cursor] - 183; cursor = parent[cursor]);
               nestlevel--;
            }
            else
            {
               if( i == '*' )       insertbop(133);
               else if( i == '/' )  insertbop(117);
               else if( i == '%' )  insertbop(101);
               else if( i == '+' )  insertbop(84);
               else if( i == '-' )  insertbop(68);
               else if( i == '&' )  insertbop(51);
               else if( i == '^' )  insertbop(34);
               else if( i == '|' )  insertbop(17);
            }
         }
         else
         {
            if( i == '(' )       insertuop(183);
            else if( i == '-' )  insertuop(166);
            else if( i == '~' )  insertuop(150);
         }
      }

   if( !lasttoken )
   {
      lit = 0;
      insertuop(199);
   }
   for(i = !putchar('\b'); i++ < nestlevel; putchar(')'));

   lit = evaluate(0);
   return printf("\n= %ld (0x%lx)\n", lit, lit);
}