struct ArgDesc;

typedef int (*ArgFunc)(const struct ArgDesc *desc, const char *arg);

typedef struct ArgDesc {

  char c;

  void *data;

  ArgFunc func;

  const char *desc;

} ArgDesc;

int pargInt(const ArgDesc *desc, const char *arg)

  { *(int*)desc->data = atof(arg); return TRUE; }

int pargDouble(const ArgDesc *desc, const char *arg)

  { *(double*)desc->data = atoi(arg); return TRUE; }

int pargString(const ArgDesc *desc, const char *arg)

  { *(const char**)desc->data = arg; return TRUE; }

int parseArgs(const ArgDesc *descs, int argc, char **argv) {

  for(; argc; --argc, ++argv) {

    int found = FALSE;

    for(const ArgDesc *desc = descs; desc->c && desc->data; ++desc) {

      if ((*argv)[0] == '-' && (*argv)[1] == desc->c && !(*argv)[2]) {

        if (desc->func) {

          --argc; ++argv;

          if (!argc || !desc->func(desc, *argv)) {

            fprintf(stderr, "Wrong argument for -%c: %s\n", desc->c, *argv);

            fflush(stderr);

            return FALSE;

          }

        } else {

          *((int*)desc->data) = TRUE;

        }

        found = TRUE;

        break;

      }

    }

    if (!found) {

      fprintf(stderr, "Unknown arg: %s\n", *argv);

      fflush(stderr);

      return FALSE;

    }

  }

  return TRUE;

}

void printUsage(const ArgDesc *descs) {

  printf("Available command-line arguments:\n");

  for(const ArgDesc *desc = descs; desc->c && desc->data; ++desc)

    printf("   -%c %s - %s\n", desc->c, desc->func ? "<arg>" : "     ", desc->desc);</arg>

  fflush(stdout);

}