Optimize undefended minor check.

[stockfish] / src / misc.cpp

diff --git a/src/misc.cpp b/src/misc.cpp
index 8cfba7341fa7fe7256fdaafa440dc3140ae9dbcd..8bc413f47be9657217ce0151a0604702f3b100c0 100644 (file)
--- a/src/misc.cpp
+++ b/src/misc.cpp
@@ -105,6 +105,68 @@ void dbg_print() {
 }
 
 
+/// 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 while preserving
+/// usual i/o functionality and without changing a single line of code!
+/// Idea from http://groups.google.com/group/comp.lang.c++/msg/1d941c0f26ea0d81
+
+class Logger {
+
+  Logger() : in(cin.rdbuf(), file), out(cout.rdbuf(), file) {}
+  ~Logger() { start(false); }
+
+  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(), ">> "); }
+
+    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);
+    }
+
+    streambuf* buf;
+    ofstream& file;
+  };
+
+  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();
+    }
+  }
+};
+
+
+/// Trampoline helper to avoid moving Logger to misc.h
+void start_logger(bool b) { Logger::start(b); }
+
+
 /// cpu_count() tries to detect the number of CPU cores
 
 int cpu_count() {