add new example program, to organize a fuzzing corpus of .torrent files

examples/Jamfile

@@ -36,6 +36,7 @@ exe bt-get2 : bt-get2.cpp ;
 exe bt-get3 : bt-get3.cpp ;
 exe stats_counters : stats_counters.cpp ;
 exe dump_torrent : dump_torrent.cpp ;
+exe rename_torrents : rename_torrents.cpp ;
 exe torrent2magnet : torrent2magnet.cpp ;
 exe magnet2torrent : magnet2torrent.cpp ;
 exe dump_bdecode : dump_bdecode.cpp ;
@@ -49,7 +50,7 @@ explicit stage_connection_tester ;
 explicit stage ;
 explicit stage_dependencies ;
 
-install stage : client_test connection_tester torrent2magnet magnet2torrent make_torrent dump_torrent check_files upnp_test stats_counters bt-get bt-get2 simple_client dump_bdecode custom_storage : <location>. ;
+install stage : client_test connection_tester torrent2magnet magnet2torrent make_torrent dump_torrent rename_torrents check_files upnp_test stats_counters bt-get bt-get2 simple_client dump_bdecode custom_storage : <location>. ;
 install stage_client_test : client_test : <location>. ;
 install stage_connection_tester : connection_tester : <location>. ;
 

examples/rename_torrents.cpp

@@ -0,0 +1,102 @@
+/*
+
+Copyright (c) 2024, Arvid Norberg
+All rights reserved.
+
+You may use, distribute and modify this code under the terms of the BSD license,
+see LICENSE file.
+*/
+
+#include <cstdio> // for snprintf
+#include <cinttypes> // for PRId64 et.al.
+#include <fstream>
+#include <iostream>
+#include <filesystem>
+
+#include "libtorrent/entry.hpp"
+#include "libtorrent/bencode.hpp"
+#include "libtorrent/load_torrent.hpp"
+#include "libtorrent/bdecode.hpp"
+#include "libtorrent/magnet_uri.hpp"
+#include "libtorrent/span.hpp"
+
+namespace {
+
+[[noreturn]] void print_usage()
+{
+	std::cerr << R"(usage: rename_torrents input-dir output-dir
+
+This tool traversese the input directory, copying any torrent file into the
+output directory under the name of the info-hash of the torrent. This can be
+useful for organizing a fuzzing corpus.
+)";
+	std::exit(1);
+}
+
+}
+
+int main(int argc, char const* argv[]) try
+{
+	namespace fs = std::filesystem;
+
+	lt::span<char const*> args(argv, argc);
+
+	// strip executable name
+	args = args.subspan(1);
+
+	lt::load_torrent_limits cfg;
+
+	if (args.empty() || args.size() != 2) print_usage();
+
+	char const* in_dir = args[0];
+	auto out_dir = fs::path(args[1]);
+
+	using namespace lt::literals;
+
+	for(auto& p: fs::recursive_directory_iterator(in_dir))
+	{
+		if (!p.is_regular_file()) continue;
+		if (p.path().extension() != ".torrent") continue;
+
+		try
+		{
+			lt::add_torrent_params const atp = lt::load_torrent_file(p.path(), cfg);
+			std::stringstream new_name;
+			if (atp.info_hashes.has_v1())
+				new_name << atp.info_hashes.v1;
+			if (atp.info_hashes.has_v2())
+			{
+				if (atp.info_hashes.has_v1())
+					new_name << "-";
+				new_name << atp.info_hashes.v2;
+			}
+			new_name << ".torrent";
+			try
+			{
+				fs::copy(p.path(), out_dir / fs::path(new_name.str()));
+				std::cout << "\33[2K\r" << p.path();
+				std::cout.flush();
+			}
+			catch (std::system_error const& err)
+			{
+				if (err.code() != std::errc::file_exists)
+				{
+					std::cerr << "\33[2K\rfailed to copy: " << p.path()
+						<< " -> " << (out_dir / fs::path(new_name.str()))
+						<< ": " << err.code().message() << "\n\n";
+				}
+			}
+		}
+		catch (std::system_error const& err)
+		{
+			std::cerr << "\33[2K\rfailed to load " << p.path()
+				<< ": " << err.code().message() << "\n\n";
+		}
+	}
+	return 0;
+}
+catch (std::exception const& e)
+{
+	std::cerr << "ERROR: " << e.what() << "\n";
+}
+