initial commit

1 files changed, 87 insertions, 0 deletions

diff --git a/server/settings.hpp b/server/settings.hpp
new file mode 100644
index 0000000..310163f
--- /dev/null
+++ b/server/settings.hpp
@@ -0,0 +1,87 @@
+#pragma once
+
+#include <boost/filesystem.hpp>
+#include <boost/program_options.hpp>
+
+#include <exception>
+#include <iostream>
+#include <string>
+#include <thread>
+#include <vector>
+
+namespace math::server {
+
+struct Settings {
+    static constexpr unsigned DEFAULT_PORT = 18000;
+
+    static unsigned default_threads() { return std::thread::hardware_concurrency(); }
+
+    unsigned m_port;
+    unsigned m_threads;
+
+    bool exit_with_usage() const { return m_vm.count("help"); }
+
+    boost::program_options::variables_map m_vm;
+};
+
+class SettingsParser {
+public:
+    explicit SettingsParser(const std::string& argv0)
+        : m_prog_name{extract_filename(argv0)}
+    {
+        m_visible.add_options()
+            ("help,h",
+                "show this message and exit")
+            ("port,p",
+                boost::program_options::value(&m_settings.m_port)->default_value(Settings::DEFAULT_PORT),
+                "server port number")
+            ("threads,n",
+                boost::program_options::value(&m_settings.m_threads)->default_value(Settings::default_threads()),
+                "number of threads");
+    }
+
+    static const char* get_short_description() {
+        return "[-h|--help] [-p|--port] [-n|--threads]";
+    }
+
+    Settings parse(int argc, char* argv[]) {
+        boost::program_options::store(
+            boost::program_options::command_line_parser{argc, argv}
+                .options(m_visible)
+                .run(),
+            m_settings.m_vm);
+        if (m_settings.exit_with_usage()) {
+            return m_settings;
+        }
+        boost::program_options::notify(m_settings.m_vm);
+        return m_settings;
+    }
+
+    void usage() const {
+        std::cout << *this;
+    }
+
+    void usage_error(const std::exception& e) const {
+        std::cerr << "usage error: " << e.what() << '\n';
+        std::cerr << *this;
+    }
+
+private:
+    static std::string extract_filename(const std::string& path) {
+        return boost::filesystem::path{path}.filename().string();
+    }
+
+    const std::string m_prog_name;
+
+    boost::program_options::options_description m_visible;
+
+    Settings m_settings;
+
+    friend std::ostream& operator<<(std::ostream& os, const SettingsParser& parser) {
+        os << "usage: " << parser.m_prog_name << ' ' << get_short_description() << '\n';
+        os << parser.m_visible;
+        return os;
+    }
+};
+
+}