/* *******************************************************************
 *                                                                   *
 * Copyright (c) L-DGO/MIT/JGOFS                                     *
 *                                                                   *
 *                                                                   *
 * File             : mathex.c                                       *
 *                                                                   *
 * Purpose          :                                                *         
 *                                                                   *
 * Version Number   : 1.1                                            *
 *                                                                   *
 * Revision History :                                                *
 *                                                                   *
 * Date                              Developer                       *
 * ----                              ---------                       *
 *                                                                   *
 * Sat Oct 17  1992 10.00           Glenn Flierl                     *
 *                                                                   *   
 *                                                                   *
 ******************************************************************* */

/*
P-code form:
128..255 push variable j-128 [negative #'s on Sun]
1: ascii number :2  push constant
3: quote next variable
s,c,e,l,'1','i': prefix ops
=,+,-,*,/,^: infix ops
0: end
*/
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <ctype.h>
double atof();
double strtod();

#define TOKEN 40
#define NPREFIX 6
#define PRIORITY "  $ (), = +-*/^ "

static char prefix[NPREFIX][TOKEN]={"sin","cos","exp","ln","log10","int"};
static char prefixcode[NPREFIX][2]={"s","c","e","l","1","i"};

int parsex(s,names,ntotal)
char *s,names[][TOKEN];
int *ntotal;
{
int opstkp;
float f;
char opstack[20][TOKEN];
int opprior[20];
char *t,*t1,tok[TOKEN],tmp[255];
int i,j,k,lookop,tmpc;

/* printf("%s\n",s); */
tmpc=0;
tmp[0]='\0';
opstkp= 0;
opstack[0][0]=0;
opprior[0]=0;
lookop=0;
strcat(s,"$");
t=s;
while(t != NULL)
  {
    if(isalpha(*t)){
      i=strcspn(t,"+-*^/()$=");
      strncpy(tok,t,i);
      tok[i]='\0';
      t += i;
      if(lookop){
       sprintf(s,"Looking for operator, found %s\n",tok);
       return 1;
      }
      else {
	for(i=0;i<NPREFIX;i++) if (!strcmp(tok,prefix[i]))break;
	if(i<NPREFIX){
	  strcpy(opstack[++opstkp],prefixcode[i]);
	  opprior[opstkp] = (int)strlen(PRIORITY)/2-1;
	}
	else {
	  for(i=0;i<*ntotal;i++) if(!strcmp(tok,names[i]))break;
	  if(i== *ntotal){
	    strcpy(names[i],tok);
	    (*ntotal)++;
	  };
	  tmp[tmpc++]=128+i;
	  tmp[tmpc]=0;
	  lookop=1;
	};
      };
    }
    else if(isdigit(*t) || *t=='.'){
      f=(float)strtod(t,&t1);
      if(lookop){
      }
      else {
	tmp[tmpc++]=1;
	strncpy(tmp+tmpc,t,t1-t);
	tmpc += t1-t;
	tmp[tmpc++]=2;
	tmp[tmpc]=0;
	lookop=1;
      };
      t=t1;
    }
    else {
      tok[0]= *t;
      tok[1]='\0';
      t++;
      if(lookop){
	k = (int)strcspn(PRIORITY,tok)/2;
	if(*tok != ')'){
	  if(*tok == '='){
	    tmp[tmpc+1]='\0';
	    tmp[tmpc]=tmp[tmpc-1];
	    tmp[tmpc-1]=3;
	    tmpc++;};
	  while (k<=opprior[opstkp])strcat(tmp,opstack[opstkp--]);
	  tmpc=strlen(tmp);
	  strcpy(opstack[++opstkp],tok);
	  opprior[opstkp]=k;
/*	  printf("pushr %d %s %d %d\n",opstkp,tok,opstack[opstkp],k); */
	  lookop=0;
	}else {
	  while (k<opprior[opstkp])strcat(tmp,opstack[opstkp--]);
	  tmpc=strlen(tmp);
         if(k != opprior[opstkp]){sprintf(s,"Right Paren Error\n");
             return 1;};
	  opstkp--;
	};
      }
      else {
        if(!strcmp(tok,"-")){
	  strcpy(opstack[++opstkp],"#");
	  opprior[opstkp] = (int) strlen(PRIORITY)/2-1;}
	else if(!strcmp(tok,"(")){
	  opstack[++opstkp][0]=0;
	  opprior[opstkp] = (int)strcspn(PRIORITY,tok)/2;}
       else {sprintf(s,"Expected const, left paren or var. ");return 1;};
      };
    };
    if (!strcmp(tok,"$"))t=NULL;
/*    printf("tmp=%s\n",tmp); */
/*     for(i=0;i<strlen(tmp);i++)printf(" %d",(int)tmp[i]); */
/*     printf("\n"); */
  };
strcpy(s,tmp);
return 0;
}

float conv(s)
char *s;
{
if (isdigit(*s) || *s=='.' || *s=='-' || *s=='+')return (float)atof(s);
else return -9999.0;
}

oneop(x)
float x;
{
if (x == -9999.0) return 0;
return 1;
}

twoop(x,y)
float x,y;
{
if( x == -9999.0 || y == -9999.0) return 0;
return 1;
}

int execute(s,values)
char *s;
char values[][TOKEN];
{
int i;
float stack[20];
int stkp;
char *t,*sp;

sp=s;
stkp= -1;
while (*sp){
i=(int)(*sp);
/* printf("%d %c\n",i,*sp); */
#if IRIX || IBM
if (i>127){
  stack[++stkp]=conv(values[i-128]);
#else
if (i<0){
  stack[++stkp]=conv(values[128+i]);
#endif
}
else
switch(*sp){
 case 1:stack[++stkp]=(float)strtod(sp+1,&t);sp=t;break;
 case 3:stack[++stkp]=(float)*(++sp);break;
 case 's':if (oneop(stack[stkp]))stack[stkp]=sin(stack[stkp]);break;
 case 'c':if (oneop(stack[stkp]))stack[stkp]=cos(stack[stkp]);break;
 case 'e':if (oneop(stack[stkp]))stack[stkp]=exp(stack[stkp]);break;
 case 'l':if (oneop(stack[stkp]))stack[stkp]=log(stack[stkp]);break;
 case '1':if (oneop(stack[stkp]))stack[stkp]=log10(stack[stkp]);break;
#if IBM
 case 'i':if (oneop(stack[stkp]))stack[stkp]=trunc(stack[stkp]);break;
#elif HP || SOL
 case 'i':if (oneop(stack[stkp]))i=stack[stkp];stack[stkp]=i;break;
#else
 case 'i':if (oneop(stack[stkp]))stack[stkp]=aint(stack[stkp]);break;
#endif
 case '#':if (oneop(stack[stkp]))stack[stkp]= -stack[stkp];break;
#if IRIX || IBM
 case '=':if(oneop(stack[stkp])) {stkp--;
             sprintf(values[(int)stack[stkp]-128],"%f",stack[stkp+1]);
 	     stkp--;}
          else {stkp -= 2;strcpy(values[(int)stack[stkp+1]-128],"nd");};
          break;
#else
 case '=':if(oneop(stack[stkp])) {stkp--;
            sprintf(values[128+(int)stack[stkp]],"%f",stack[stkp+1]);
	    stkp--;}
          else {stkp -= 2;strcpy(values[128+(int)stack[stkp+1]],"nd");};
          break;
#endif
 case '+':stkp--;if(twoop(stack[stkp],stack[stkp+1]))
          stack[stkp]=stack[stkp]+stack[stkp+1];else stack[stkp]= -9999.0;break;
 case '-':stkp--;if(twoop(stack[stkp],stack[stkp+1]))
          stack[stkp]=stack[stkp]-stack[stkp+1];else stack[stkp]= -9999.0;break;
 case '*':stkp--;if(twoop(stack[stkp],stack[stkp+1]))
          stack[stkp]=stack[stkp]*stack[stkp+1];else stack[stkp]= -9999.0;break;
 case '/':stkp--;if(twoop(stack[stkp],stack[stkp+1]))
          stack[stkp]=stack[stkp]/stack[stkp+1];else stack[stkp]= -9999.0;break;
 case '^':stkp--;if(twoop(stack[stkp],stack[stkp+1]))
    {if(stack[stkp]>0)stack[stkp]=pow(stack[stkp],stack[stkp+1]);
    else if(stack[stkp]==0)stack[stkp]=0.0;
    else stack[stkp]= -pow(-stack[stkp],stack[stkp+1]);
   } else stack[stkp]= -9999.0;
    break;
 };
sp++;
/* for(i=0;i<=stkp;i++)printf("%f ",stack[i]); */
/* printf("\n"); */
};
return 0;
}

/*
main(argc,argv)
int argc;
char *argv[];
{
static char names[][TOKEN]={"press","temp","sal","",""};
static char values[][TOKEN]={"100","12.55","33.462","",""};
int ntotal=3;
char tmp[255];
int i;

strcpy(tmp,argv[1]);
parse(tmp,names,&ntotal);
for (i=0;i<strlen(tmp);i++)printf("%d %c\n",(int)tmp[i],tmp[i]);
printf("ntotal = %d\n",ntotal);
execute(tmp,values);
for(i=0;i<ntotal;i++)printf("%s\n",values[i]);
}
*/