-/// 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) {
-
- static Logger l;
-
- if (b && !l.file.is_open())
- {
- l.file.open("io_log.txt", ifstream::out | ifstream::app);
- cin.rdbuf(&l.in);
- cout.rdbuf(&l.out);
- }
- else if (!b && l.file.is_open())
- {
- cout.rdbuf(l.out.buf);
- cin.rdbuf(l.in.buf);
- l.file.close();
- }
- }
-};
-
-