+using namespace std::chrono;
+
+namespace {
+
+/// Version number. If Version is left empty, then compile date in the format
+/// DD-MM-YY and show in engine_info.
+const string Version = "";
+
+/// Debug counters
+int64_t hits[2], means[2];
+
+/// Our fancy logging facility. The trick here is to replace cin.rdbuf() and
+/// cout.rdbuf() with two Tie objects that tie cin and cout to a file stream. We
+/// can toggle the logging of std::cout and std:cin at runtime whilst preserving
+/// usual i/o functionality, all without changing a single line of code!
+/// Idea from http://groups.google.com/group/comp.lang.c++/msg/1d941c0f26ea0d81
+
+struct Tie: public streambuf { // MSVC requires splitted streambuf for cin and cout
+
+ Tie(streambuf* b, ofstream* f) : buf(b), file(f) {}
+
+ int sync() { return file->rdbuf()->pubsync(), buf->pubsync(); }
+ int overflow(int c) { return log(buf->sputc((char)c), "<< "); }
+ int underflow() { return buf->sgetc(); }
+ int uflow() { return log(buf->sbumpc(), ">> "); }
+
+ streambuf* buf;
+ ofstream* file;
+
+ int log(int c, const char* prefix) {
+
+ static int last = '\n';
+
+ if (last == '\n')
+ file->rdbuf()->sputn(prefix, 3);
+
+ return last = file->rdbuf()->sputc((char)c);
+ }
+};
+
+class Logger {
+
+ Logger() : in(cin.rdbuf(), &file), out(cout.rdbuf(), &file) {}
+ ~Logger() { start(false); }
+
+ ofstream file;
+ Tie in, out;
+
+public:
+ static void start(bool b) {