getsym.c

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                rval = ival;
        if(**ptr == '-') {
                exmul = 0.1;
                (*ptr)++;
                }
        else {
                exmul = 10.0;
								if (**ptr == '+')
									(*ptr)++;
				}
        getbase(10,ptr);
        if(ival > 255)
                generror(ERR_FPCON,0,0);
        else
                while(ival--)
                        expo *= exmul;
        rval *= expo;
				lastst = rconst;
}
 
/*
 *      getnum - get a number from input.
 *
 *      getnum handles all of the numeric input. it accepts
 *      decimal, octal, hexidecimal, and floating point numbers.
 */
void getnum(void)
{
	int isfloat=FALSE;
	char buf[50],*ptr = buf;
	while (isxdigit(lastch) || lastch == 'x' || lastch == 'X') {
		*ptr++ = lastch;
		getch();
	}
	if (lastch == '.') {
		isfloat = TRUE;
		*ptr++=lastch;
		getch();
		while (isdigit(lastch)) {
			*ptr++ = lastch;
			getch();
		}
	}
	if (lastch == 'e' || lastch == 'E') {
		isfloat = TRUE;
		*ptr++ = lastch;
		getch();
		if (lastch == '+' || lastch == '-') {
			*ptr++=lastch;
			getch();
		}
		while (isdigit(lastch)) {
			*ptr++ = lastch;
			getch();
		}
	}
	if (lastch == 'F') {
		isfloat = TRUE;
	}
	*ptr = 0;
	ptr = buf;
	if (!isfloat) {
		if (*ptr == '0') {
			ptr++;
      if(*ptr == 'x' || *ptr == 'X') {
      	ptr++;
      	getbase(16,&ptr);
    	}
    	else getbase(8,&ptr);
   	}
		else
			getbase(10,&ptr);
		if (lastch == 'U') {
			lastst = iuconst;
			getch();
			if (lastch == 'L') {
				lastst = luconst;
				getch();
			}
		}
		else if (lastch == 'L') {
			lastst = iconst;
			getch();
			if (lastch == 'U') {
				lastst = luconst;
				getch();
			}
		}
	}
  else    {
                getbase(10,&ptr);
	                if(*ptr == '.') {
											ptr++;
                        rval = ival;    /* float the integer part */
                        getfrac(&ptr);      /* add the fractional part */
                        lastst = rconst;
  		                  }
      	          if(*ptr == 'e' || *ptr == 'E') {
                        ptr++;
                        getexp(&ptr);       /* get the exponent */
                        }
									if (lastch == 'F') {
											if (lastst != rconst) {
												rval = ival;
											}
											lastst = fconst;
											getch();
									}
									else if (lastch == 'L') {
											if (lastst != rconst) {
												rval = ival;
											}
											lastst = lrconst;
											getch();
									}
								}
}
 
int getsym2(void) 
/*
 * translate character sequences to appropriate token names
 */
{       register int    i, j;
				int size;
swlp:
						 switch(lastch) {
                case '+':
                        getch();
                        if(lastch == '+') {
                                getch();
                                lastst = autoinc;
                                }
                        else if(lastch == '=') {
                                getch();
                                lastst = asplus;
                                }
                        else lastst = plus;
                        break;
                case '-':
                        getch();
                        if(lastch == '-') {
                                getch();
                                lastst = autodec;
                                }
                        else if(lastch == '=') {
                                getch();
                                lastst = asminus;
                                }
                        else if(lastch == '>') {
                                getch();
#ifdef CPLUSPLUS
																if (prm_cplusplus && lastch == '*') {
																	getch();
																	lastst = pointstar;
																}
																else
#endif
                                	lastst = pointsto;
                                }
                        else lastst = minus;
                        break;
                case '*':
                        getch();
                        if(lastch == '=') {
                                getch();
                                lastst = astimes;
                                }
                        else lastst = star;
                        break;
                case '/':
                        getch();
                        if(lastch == '=') {
                                getch();
                                lastst = asdivide;
                                }
                        else lastst = divide;
                        break;
                case '^':
                        getch();
                        if(lastch == '=') {
                                getch();
                                lastst = asxor;
                                }
                        else lastst = uparrow;
                        break;
                case ';':
                        getch();
                        lastst = semicolon;
                        break;
                case ':':
                        getch();
#ifdef CPLUSPLUS
												if (prm_cplusplus && lastch == ':') {
													lastst = classsel;
													getch();
												}
												else
#endif
                        	lastst = colon;
                        break;
                case '=':
                        getch();
                        if(lastch == '=') {
                                getch();
                                lastst = eq;
                                }
                        else lastst = assign;
                        break;
                case '>':
                        getch();
                        if(lastch == '=') {
                                getch();
                                lastst = geq;
                                }
                        else if(lastch == '>') {
                                getch();
                                if(lastch == '=') {
                                        getch();
                                        lastst = asrshift;
                                        }
                                else lastst = rshift;
                                }
                        else lastst = gt;
                        break;
                case '<':
                        getch();
												if (incconst) {
                      	  for(i = 0;i < MAX_STRLEN;++i) {
                                if(lastch == '>')
                                        break;
                                if((j = getsch()) == -1)
                                        break;
                                else
                                        laststr[i] = j;
	                              }
  	                      laststr[i] = 0;
    	                    lastst = sconst;
      	                  if(lastch != '>')
        	                        generror(ERR_NEEDCHAR,'>',0);
          	              else
            	                    getch();
												} else
                        	if(lastch == '=') {
                                getch();
                                lastst = leq;
                                }
                        	else if(lastch == '<') {
                                getch();
                                if(lastch == '=') {
                                        getch();
                                        lastst = aslshift;
                                        }
                                else lastst = lshift;
                                }
                        	else lastst = lt;
                        break;
                case '\'':
                        getch();
                        ival = getsch();        /* get a string char */
                        if(lastch != '\'')
                                generror(ERR_NEEDCHAR,'\'',0);
                        else
                                getch();
                        lastst = cconst;
                        break;
								case 0x2d4:
												getch();
												i=0;
												while (lastch != '\"' && lastch)
													i=installphichar(lastch,laststr,i);
												if ((lastch & 0x7f) != '\"')
        	                        generror(ERR_NEEDCHAR,'\"',0);
          	              else
            	                    getch();
												size = strlen(laststr);
												lastst = sconst;
												break;
                case '\"':
					 							size = 0;
												while (lastch == '\"') {
                        	getch();
                        	for(i = size;i < MAX_STRLEN;++i) {
                                if(lastch == '\"')
                                        break;
                                if((j = getsch()) == -1)
                                        break;
                                else
                                        laststr[i] = j;
                                }
	                        laststr[i] = 0;
													size = i;
    	                    lastst = sconst;
      	                  if(lastch != '\"')
        	                        generror(ERR_NEEDCHAR,'\"',0);
          	              else
            	                    getch();
												}
                        break;
                case '!':
                        getch();
                        if(lastch == '=') {
                                getch();
                                lastst = neq;
                                }
                        else lastst = not;
                        break;
                case '%':
                        getch();
                        if(lastch == '=') {
                                getch();
                                lastst = asmodop;
                                }
                        else lastst = modop;
                        break;
                case '~':
                        getch();
                        lastst = compl;
                        break;
                case '.':
												if (isdigit(*lptr))
													getnum();
												else {	
	                        getch();
#ifdef CPLUSPLUS
													if (prm_cplusplus && lastch == '*') {
														getch();
														lastst = dotstar;
													}
													else 
#endif
													  if (lastch == '.') {
													  	getch();
															if (lastch == '.') {
																getch();
																lastst = ellipse;
																break;
															}
															else {
          	        	      	  generror(ERR_ILLCHAR,lastch,0);
															}
														}
                        	lastst = dot;
												}
                        break;
                case ',':
                        getch();
                        lastst = comma;
                        break;
                case '&':
                        getch();
                        if( lastch == '&') {
                                lastst = land;
                                getch();
                                }
                        else if( lastch == '=') {
                                lastst = asand;
                                getch();
                                }
                        else
                                lastst = and;
                        break;
                case '|':
                        getch();
                        if(lastch == '|') {
                                lastst = lor;
                                getch();
                                }
                        else if( lastch == '=') {
                                lastst = asor;
                                getch();
                                }
                        else
                                lastst = or;
                        break;
                case '(':
                        getch();
                        lastst = openpa;
                        break;
                case ')':
                        getch();
                        lastst = closepa;
                        break;
                case '[':
                        getch();
                        lastst = openbr;
                        break;
                case ']':
                        getch();
                        lastst = closebr;
                        break;
                case '{':
                        getch();
                        lastst = begin;
                        break;
                case '}':
                        getch();
                        lastst = end;
                        break;
                case '?':
                        getch();
                        lastst = hook;
                        break;
                default:
												if (iscommentchar(lastch)) {
													do {
														getch();
													} while (!iscommentchar(lastch) && lastch != '\n');
												}
												else
                        	generror(ERR_ILLCHAR,lastch,0);
                        getch();
												return 1;
                }
	return 0;
}
/*
 *      getsym - get next symbol from input stream.
 *
 *      getsym is the basic lexical analyzer.  It builds
 *      basic tokens out of the characters on the input
 *      stream and sets the following global variables:
 *
 *      lastch:         A look behind buffer.
 *      lastst:         type of last symbol read.
 *      laststr:        last string constant read.
 *      lastid:         last identifier read.
 *      ival:           last integer constant read.
 *      rval:           last real constant read.
 *
 *      getsym should be called for all your input needs...
 */
void     getsym(void)
{

				if (backupchar != -1) {
					lastst = backupchar;
					backupchar = -1;
					return;
				}
				if (cantnewline && !*lptr) {
					lastst = eol;
					return;
				}
        while(iswhitespacechar(lastch)) {
          getch();
					if (cantnewline && !*lptr) {
						lastst = eol;
						return;
					}
				}
        if( lastch == -1)
                lastst = eof;
        else if(isdigit(lastch))
                getnum();
        else if(isstartchar(lastch)) {
                getid();
                searchkw();
				}
        else getsym2();
}
/*
 * when we need specific punctuation, call one of these routines
 */
int needpunc(enum e_sym p, int *skimlist)
{       if( lastst == p) {
                getsym();
								return(TRUE);
				}
        else
                expecttoken(p,skimlist);
	return(FALSE);
}
int needpuncexp(enum e_sym p, int *skimlist)
{       if( lastst == p) {
                getsym();
								return(TRUE);
				}
        else
                expecttokenexp(p,skimlist);
	return(FALSE);
}
/*
 * having to back up a character is rare, but sometimes...
 */
void backup(int st)
{
  backupchar = lastst;
  lastst = st;
}