bin/pc/pc.c

121 ULONG parse_expression(char *str);   /* top-level interface to parser */
122 ULONG assignment_expr(char **str);   /* assignments =, +=, *=, etc */
123 ULONG do_assignment_operator(char **str, char *var_name);
124 ULONG logical_or_expr(char **str);   /* logical OR  `||' */
125 ULONG logical_and_expr(char **str);  /* logical AND  `&&' */
126 ULONG or_expr(char **str);           /* OR  `|' */
127 ULONG xor_expr(char **str);          /* XOR `^' */
128 ULONG and_expr(char **str);          /* AND `&' */
129 ULONG equality_expr(char **str);     /* equality ==, != */
130 ULONG relational_expr(char **str);   /* relational <, >, <=, >= */
131 ULONG shift_expr(char **str);        /* shifts <<, >> */
132 ULONG add_expression(char **str);    /* addition/subtraction +, - */
133 ULONG term(char **str);              /* multiplication/division *,%,/ */
134 ULONG factor(char **str);            /* negation, logical not ~, ! */
135 ULONG get_value(char **str);
140 char *skipwhite(char *str);          /* skip over input white space */
304 parse_expression(char *str)
307   char *ptr = str;
331 assignment_expr(char **str)
338   *str = skipwhite(*str);
339   orig_str = *str;
341   var_name = get_var_name(str);
343   *str = skipwhite(*str);
344   if (**str == EQUAL && *(*str+1) != EQUAL)
346      *str = skipwhite(*str + 1);     /* skip the equal sign */
348      val = assignment_expr(str);     /* go recursive! */
355   else if (((**str == PLUS  || **str == MINUS    || **str == OR ||
356 	     **str == TIMES || **str == DIVISION || **str == MODULO ||
357 	     **str == AND   || **str == XOR) && *(*str+1) == EQUAL) ||
358 	   strncmp(*str, "<<=", 3) == 0 || strncmp(*str, ">>=", 3) == 0)
360      val = do_assignment_operator(str, var_name);
364      *str = orig_str;
365      val = logical_or_expr(str);     /* no equal sign, just get var value */
367      *str = skipwhite(*str);
368      if (**str == EQUAL)
382 do_assignment_operator(char **str, char *var_name)
388   operator = **str;
391     *str = skipwhite(*str + 3);
393     *str = skipwhite(*str + 2);     /* skip the assignment operator */
395   val = assignment_expr(str);       /* go recursive! */
446 logical_or_expr(char **str)
450   *str = skipwhite(*str);
452   sum = logical_and_expr(str);
454   *str = skipwhite(*str);
455   while(**str == OR && *(*str + 1) == OR)
457      *str = skipwhite(*str + 2);   /* advance over the operator */
459      val = logical_and_expr(str);
470 logical_and_expr(char **str)
474   *str = skipwhite(*str);
476   sum = or_expr(str);
478   *str = skipwhite(*str);
479   while(**str == AND && *(*str + 1) == AND)
481      *str = skipwhite(*str + 2);   /* advance over the operator */
483      val = or_expr(str);
493 or_expr(char **str)
497   *str = skipwhite(*str);
499   sum = xor_expr(str);
501   *str = skipwhite(*str);
502   while(**str == OR && *(*str+1) != OR)
504      *str = skipwhite(*str + 1);   /* advance over the operator */
506      val = xor_expr(str);
517 xor_expr(char **str)
521   *str = skipwhite(*str);
523   sum = and_expr(str);
525   *str = skipwhite(*str);
526   while(**str == XOR)
528      *str = skipwhite(*str + 1);   /* advance over the operator */
530      val = and_expr(str);
541 and_expr(char **str)
545   *str = skipwhite(*str);
547   sum = equality_expr(str);
549   *str = skipwhite(*str);
550   while(**str == AND && *(*str+1) != AND)
552      *str = skipwhite(*str + 1);   /* advance over the operator */
554      val = equality_expr(str);
564 equality_expr(char **str)
569   *str = skipwhite(*str);
571   sum = relational_expr(str);
573   *str = skipwhite(*str);
574   while((**str == EQUAL && *(*str+1) == EQUAL) ||
575 	(**str == BANG  && *(*str+1) == EQUAL))
577      op = **str;
579      *str = skipwhite(*str + 2);   /* advance over the operator */
581      val = relational_expr(str);
594 relational_expr(char **str)
599   *str = skipwhite(*str);
601   sum = shift_expr(str);
603   *str = skipwhite(*str);
604   while(**str == LESS_THAN || **str == GREATER_THAN)
607      op = **str;
609      if (*(*str+1) == EQUAL)
612 	*str = *str+1;             /* skip initial operator */
615      *str = skipwhite(*str + 1);   /* advance over the operator */
617      val = shift_expr(str);
643 shift_expr(char **str)
648   *str = skipwhite(*str);
650   sum = add_expression(str);
652   *str = skipwhite(*str);
653   while((strncmp(*str, "<<", 2) == 0) || (strncmp(*str, ">>", 2) == 0))
655      op = **str;
657      *str = skipwhite(*str + 2);   /* advance over the operator */
659      val = add_expression(str);
674 add_expression(char **str)
679   *str = skipwhite(*str);
681   sum = term(str);
683   *str = skipwhite(*str);
684   while(**str == PLUS || **str == MINUS)
686      op = **str;
688      *str = skipwhite(*str + 1);   /* advance over the operator */
690      val = term(str);
705 term(char **str)
711   sum = factor(str);
712   *str = skipwhite(*str);
719   if (**str != TIMES     && **str != DIVISION && **str != MODULO &&
720       **str != PLUS      && **str != MINUS    && **str != OR     &&
721       **str != AND       && **str != XOR      && **str != BANG   &&
722       **str != NEGATIVE  && **str != TWIDDLE  && **str != RPAREN &&
723       **str != LESS_THAN && **str != GREATER_THAN && **str != SEMI_COLON &&
724       strncmp(*str, "<<", 2) != 0 && strncmp(*str, ">>", 2) &&
725       **str != EQUAL && **str != '\0')
727      fprintf(stderr, "Parsing stopped: unknown operator %s\n", *str);
731   while(**str == TIMES || **str == DIVISION || **str == MODULO)
733      op   = **str;
734      *str = skipwhite(*str + 1);
735      val = factor(str);
760 factor(char **str)
767   if (**str == NEGATIVE || **str == PLUS || **str == TWIDDLE || **str == BANG)
769      op = **str;                     /* must be a unary op */
771      if ((op == NEGATIVE && *(*str + 1) == NEGATIVE) ||  /* look for ++/-- */
772 	 (op == PLUS     && *(*str + 1) == PLUS))
774 	*str = *str + 1;
778      *str = skipwhite(*str + 1);
779      var_name_ptr = *str;          /* save where the varname should be */
782   val = get_value(str);
784   *str = skipwhite(*str);
832 get_value(char **str)
838   if (**str == SINGLE_QUOTE)         /* a character constant */
842      *str = *str + 1;                /* advance over the leading quote */
844      for(i=0; **str && **str != SINGLE_QUOTE && i < sizeof(LONG); *str+=1,i++)
846 	if (**str == '\\')  /* escape the next char */
847 	  *str += 1;
850 	val |= (ULONG)((unsigned)**str);
853      if (**str != SINGLE_QUOTE)       /* constant must have been too long */
857 	while(**str && **str != SINGLE_QUOTE)
858 	  *str += 1;
860      else if (**str != '\0')
861        *str += 1;
863   else if (isdigit(**str))            /* a regular number */
865      val = STRTOUL(*str, str, 0);
867      *str = skipwhite(*str);
869   else if (**str == USE_LAST_RESULT)  /* a `.' meaning use the last result */
872      *str = skipwhite(*str+1);
874   else if (**str == LPAREN)           /* a parenthesized expression */
876      *str = skipwhite(*str + 1);
878      val = assignment_expr(str);      /* start at top and come back down */
880      if (**str == RPAREN)
881        *str = *str + 1;
885   else if (isalpha(**str) || **str == '_')          /* a variable name */
887      if ((var_name = get_var_name(str)) == NULL)
904      *str = skipwhite(*str);
905      if (strncmp(*str, "++", 2) == 0 || strncmp(*str, "--", 2) == 0)
910 	    if (**str == '+')
914 	    *str = *str + 2;
927      fprintf(stderr, "  Got: `%s'\n", *str);
1062 get_var_name(char **str)
1067   if (isalpha(**str) == 0 && **str != '_')
1078   while(**str && (isalnum(**str) || **str == '_'))
1088      buff[i++] = **str;
1089      *str = *str+1;
1094   while (isalnum(**str) || **str == '_')  /* skip over any remaining junk */
1095     *str = *str+1;
1103 skipwhite(char *str)
1105   if (str == NULL)
1108   while(*str && (*str == ' ' || *str == '\t' || *str == '\n' || *str == '\f'))
1109     str++;
1111   return str;