piface/src/mainclass.cpp

#include "mainclass.hh"
#include <iostream>
#include <libgen.h>
#include <sysexits.h>
#include <climits>
#include <getopt.h>

MainClass::MainClass(int argc, char* argv[])
  : argc_(argc)
  , argv_(argv)
{
}

int MainClass::usage()
{
  std::cerr << "Usage: " << basename(argv_[0]) << std::endl <<
    " [--device DEVICE|--device=DEVICE|-e DEVICE]" << std::endl <<
    " [--up OUTPUT|--up=OUTPUT|-u OUTPUT]" << std::endl <<
    " [--down OUTPUT|--down=OUPUT|-d OUTPUT]" << std::endl <<
    " [--sleep MS|--sleep=MS|-s MS]" << std::endl <<
    " [--help|-h]" << std::endl;
  std::cerr << std::endl << "Controls the output pins of a PiFace digital IO."
    << std::endl << std::endl;
  std::cerr << "--device \tSwitch to the provided device."
    << std::endl << "--up \t\tEnable the provided ouput pin."
    << std::endl << "--down \t\tDisable the provided output pin."
    << std::endl << "--sleep \tSleep for the provided amount of milliseconds."
    << std::endl << "--help \t\tDisplay this message."
    << std::endl << std::endl;
  std::cerr << "OUTPUT \t: The output pin to enable/disable. 0 <= OUTPUT <= 7."
    << std::endl << "MS \t: The number of milliseconds to sleep. 0 <= MS <= "
    << UINT_MAX << "."
    << std::endl << "DEVICE \t: The device number. Default is 0. "
    "0 <= DEVICE <= 4." << std::endl;
  return EX_USAGE;
}

bool MainClass::bad_value_()
{
  extern int optind;
  extern char* optarg;
  std::cerr << "Bad value " << optarg <<
    " for option " << argv_[optind - 2] << std::endl << std::endl;
  return false;
}

bool MainClass::build_actions_()
{
  option opts[] = {
    {"device", 1, 0, 'e'},
    {"up", 1, 0, 'u'},
    {"down", 1, 0, 'd'},
    {"sleep", 1, 0, 's'},
    {"help", 0, 0, 'h'},
    {0, 0, 0, 0}
  };
  int opt;
  extern int optind;
  extern char* optarg;
  char* endptr;
  while ((opt = getopt_long(argc_, argv_, "e:u:d:s:h", opts, 0)) != -1)
  {
    if (!optarg)
      return false;
    long int arg = strtol(optarg, &endptr, 10);
    if (arg < 0)
      return bad_value_();
    if (opt == 'e')
    {
      if (arg > 4)
        return bad_value_();
      actions_.push_back([arg]() -> bool
          {
          return true;
          });
    }
    else if (opt == 'u')
    {
      if (arg > 7)
        return bad_value_();
    }
    else if (opt == 'd')
    {
      if (arg > 7)
        return bad_value_();
    }
    else if (opt == 's')
    {
      if (arg > UINT_MAX)
        return bad_value_();
    }
    else
      return false;
  }
  return optind == argc_;
}

int MainClass::execute()
{
  if (argc_ <= 2 || !build_actions_())
    return usage();
  for (auto f : actions_)
    if (!f())
      return 1;
  return 0;
}