qcalc-cli.c

嵌入式linux下的一个高级计算器程序的源码

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <readline/readline.h>
#include <readline/history.h>
#include <math.h>
#include <malloc.h>
#include <sys/param.h>

#include "calculator.h"

void
calculator_exit(void)
{
  FILE        *config;
  char         npath[PATH_MAX];
  char        *env;

  env = getenv("HOME");
  if (env) 
    strcpy(npath, env);
  else
    strcpy(npath, "/tmp");
  
  strcat(npath, "/.kde/share/apps/qcalc/qcalc.conf");

  config = fopen (npath, "wt");
  if (config) {
    WriteHistory(config);
    fclose(config);
  }
  exit(0);
}

int
main (void)
{
  FILE        *config;
  char         result[40], exp[10], ausg[40], *text, *thist;
  double       res, man, expo;
  int          iexpo, i, k, j;
  char         npath[PATH_MAX], syspath[PATH_MAX];
  char        *env;
  char        *line_read = (char*) NULL;

  env = getenv("HOME");
  if (env) 
    strcpy(npath, env);
  else
    strcpy(npath, "/tmp");
  
  strcat(npath, "/.kde/share/apps/qcalc");

  // create a subdirectory for the configuration file; 
  // there is a error message, if the directory already 
  // exists; this is ignored at the moment
  strcpy(syspath, "mkdir ");
  strcat(syspath, npath);
  system(syspath);

  strcat(npath, "/qcalc.conf");
  config = fopen (npath, "rt");
  if (config) {
    ReadHistory(config);
    fclose(config);
  }

  using_history ();

  for (i = 0; i < CalculatorCmdHistoryAnz; i++) 
    add_history(CalculatorCmdHistory[i]);
 
  while (1) {
    res = 0;
    CalculatorError = ERR_NOERROR;

    line_read = (char*) readline("qcalc > ");
    text = malloc(strlen(line_read)+1);
    strcpy(text, line_read);

    // remember the formula, because "Calculator" destroys the string
    thist = (char*) malloc(strlen(text)+1);
    strcpy(thist, text);

    if (strstr(text, "quit")) calculator_exit();
    if (strstr(text, "exit")) calculator_exit();
    if (strstr(text, "list fkt")) {
      printf ("Functions:\n");
      for (i = 1; i <= CalculatorFktAnz; i++) {
	printf ("  %s (", CalculatorFkt[i].Name);
	for (j = 0; j < CalculatorFkt[i].Vars; j++) {
	  printf("%s", CalculatorFkt[i].Var[j].Name);
	  if (j < CalculatorFkt[i].Vars-1) printf (";");
	}
	printf (")\n");
      }
    } else if (strstr(text, "list var")) {
      printf ("Variables:\n");
      for (i = 0; i < CalculatorFkt[0].Vars; i++)
	printf ("%20s = %e\n", CalculatorFkt[0].Var[i].Name, CalculatorFkt[0].Var[i].Valu);
      
    } else {
    
      // evaluate the formula
      res = Calculator(text, &CalculatorFkt[0]);
      if ((!CalculatorError) && ((CalculatorCmdHistoryAnz == 0) || 
	  (strcmp(thist, CalculatorCmdHistory[CalculatorCmdHistoryAnz-1])))) {
	// if there is no mistake in the formula and the formula is not
	// already the last element of the history list, put the formual 
	// to the history list
	add_history (thist);
	if (CalculatorCmdHistoryAnz == 100) {
	  // the history list is full, remove the oldes entry
	  for (i = 0; i < 99; i++) 
	    CalculatorCmdHistory[i] = CalculatorCmdHistory[i+1];
	  CalculatorCmdHistoryAnz--;
	}
	CalculatorCmdHistory[CalculatorCmdHistoryAnz] = thist;
	CalculatorCmdCurhist = CalculatorCmdHistoryAnz;
	CalculatorCmdHistoryAnz++;
	free(text);
      }
      else {
	free(text);
	free(thist);
      } 
      
      if (CalculatorError) {
	// got an error, display Errormessage
	printf("Error: %s\n", calculator_errtxt[CalculatorError-1]);
      }
      else {

	// don't display garbage values
	if (fabs(res) > 1.e-301) 
	  expo  = log10(fabs(res));
	else
	  expo  = 0;
	
	// "normalize" the exponent for display in engineering format
	if (expo < -2) expo -= 3;
	iexpo = (int)(expo/3)*3; 
	// check for floating point errors, which were not signaled by
	// the variable CalculatorError
	if ((iexpo > 1000) || (iexpo < -1000)){
	  printf("Floating Point Error\n");
	}
	else {
	  // calculate the mantissa for the choosen exponent
	  man   = res / pow(10, (double)iexpo); 
	  sprintf (result, "%14.12f", man);
	  
	  k = -100;
	  j = 0;
	  // insert blankes after group of 3 digits to make display
	  // more readable
	  for (i = 0; (unsigned int)i < strlen(result); i++){
	    ausg[j++] = result[i];
	    k++;
	    if (result[i] == '.') k = 0;
	    if (k == 3){
	      ausg[j++] = ' ';
	      k = 0;
	    }
	  }
	  ausg[j++] = 0;
	  
	  // remove '0' at end of string
	  for (i = strlen(ausg)-1; i > 0; i--) {
	    if ((ausg[i] == '0') || (ausg[i] == ' '))
	      ausg[i] = 0;
	    else
	      break;
	  }
	  
	  sprintf (exp,    "%+04d", iexpo);
	  // display the result
	  printf("\n Result: %s E%s\n\n", ausg, exp);
	  CalculatorCmdCurhist = CalculatorCmdHistoryAnz;
	}
      }
    }
  }
}

//  Local Variables: ***
//  mode:c++ ***
//  End: ***