Implement an options parser.

src/Options.cpp

@@ -0,0 +1,108 @@
+#include <algorithm>
+#include <iostream>
+#include <stdlib.h>
+#include <unistd.h>
+#include "Options.hpp"
+
+using namespace fmri;
+using namespace std;
+
+static void show_help(const char* progname, int exitcode)
+{
+	cerr << "Usage: " << progname << " -m MODEL -w WEIGHTS INPUTS..." << endl
+		<< endl
+		<< R"END(
+Simulate the specified network on the specified inputs.
+
+Options:
+	-h	show this message
+	-m	(required) the model file to simulate
+	-w	(required) the trained weights
+)END" << endl;
+
+	exit(exitcode);
+}
+
+static void check_file(const char * filename)
+{
+	if (access(filename, R_OK) != 0) {
+		cerr << filename << " could not be read" << endl;
+		exit(1);
+	}
+}
+
+Options Options::parse(const int argc, char * const argv[])
+{
+	string model;
+	string weights;
+
+	char c;
+
+	while ((c = getopt(argc, argv, "hm:w:")) != -1) {
+		switch (c) {
+			case 'h':
+				show_help(argv[0], 0);
+				break;
+
+			case 'w':
+				check_file(optarg);
+				weights = optarg;
+				break;
+
+			case 'm':
+				check_file(optarg);
+				model = optarg;
+				break;
+
+			case '?':
+				cerr << "Unknown option character: " << char(optopt) << endl;
+				show_help(argv[0], 1);
+				break;
+
+			default:
+				abort();
+		}
+	}
+
+	if (weights.empty()) {
+		cerr << "Weights file is required!" << endl;
+		show_help(argv[0], 1);
+	}
+
+	if (model.empty()) {
+		cerr << "Model file is required!" << endl;
+		show_help(argv[0], 1);
+	}
+
+	for_each(argv + optind, argv + argc, check_file);
+
+	vector<string> inputs(argv + optind, argv + argc);
+	if (inputs.empty()) {
+		cerr << "No inputs specified" << endl;
+		show_help(argv[0], 1);
+	}
+
+	return Options(move(model), move(weights), move(inputs));
+}
+
+Options::Options(string&& model, string&& weights, vector<string>&& inputs) noexcept:
+	modelPath(move(model)),
+	weightsPath(move(weights)),
+	inputPaths(move(inputs))
+{
+}
+
+const string& Options::model() const
+{
+	return modelPath;
+}
+
+const string& Options::weights() const
+{
+	return weightsPath;
+}
+
+const vector<string>& Options::inputs() const
+{
+	return inputPaths;
+}