From 5d50faa12b64983f87219b8b4a50ce8a6c7bcbee Mon Sep 17 00:00:00 2001
From: H.G. Muller <h.g.muller@hccnet.nl>
Date: Sat, 14 Jan 2012 13:13:20 +0100
Subject: [PATCH] Eliminate polling in Windows

Also use pipe-based synchronization here.
---
 UCI2WB.c |   38 +++++++++++++++++++++++---------------
 1 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/UCI2WB.c b/UCI2WB.c
index 764f921..0050146 100644
--- a/UCI2WB.c
+++ b/UCI2WB.c
@@ -20,12 +20,6 @@
 #include <fcntl.h>
 #include <string.h>
 
-#ifdef _MSC_VER 
-#define SLEEP() Sleep(1) 
-#else 
-#define SLEEP() usleep(10) 
-#endif 
-
 // Set VARIANTS for in WinBoard variant feature. (With -s option this will always be reset to use "shogi".)
 #  define VARIANTS "normal,xiangqi"
 
@@ -41,6 +35,21 @@ int statDepth, statScore, statNodes, statTime, currNr, size; char currMove[20];
 FILE *toE, *fromE;
 int pid;
 
+#ifdef WIN32
+WinPipe(HANDLE *hRd, HANDLE *hWr)
+{
+  SECURITY_ATTRIBUTES saAttr;
+
+  /* Set the bInheritHandle flag so pipe handles are inherited. */
+  saAttr.nLength = sizeof(SECURITY_ATTRIBUTES);
+  saAttr.bInheritHandle = TRUE;
+  saAttr.lpSecurityDescriptor = NULL;
+
+  /* Create a pipe */
+  return CreatePipe(hRd, hWr, &saAttr, 0);
+}
+#endif
+
 #define INIT 0
 #define WAKEUP 1
 #define PAUSE 2
@@ -49,7 +58,12 @@ void
 Sync (int action)
 {
 #ifdef WIN32
-	if(action == PAUSE) while(pause) SLEEP(); // in Windows we still rely on polling. :-(
+	static HANDLE hWr, hRd; DWORD d; char c;
+	switch(action) {
+	    case INIT:   WinPipe(&hRd, &hWr); break;
+	    case WAKEUP: WriteFile(hWr, "\n", 1, &d, NULL); break;
+	    case PAUSE:  ReadFile(hRd, &c, 1, &d, NULL);
+	}
 #else
 	static int syncPipe[2];	char c;
 	switch(action) {
@@ -342,22 +356,16 @@ StartEngine(char *cmdLine, char *dir)
 #ifdef WIN32
   HANDLE hChildStdinRd, hChildStdinWr,
     hChildStdoutRd, hChildStdoutWr;
-  SECURITY_ATTRIBUTES saAttr;
   BOOL fSuccess;
   PROCESS_INFORMATION piProcInfo;
   STARTUPINFO siStartInfo;
   DWORD err;
 
-  /* Set the bInheritHandle flag so pipe handles are inherited. */
-  saAttr.nLength = sizeof(SECURITY_ATTRIBUTES);
-  saAttr.bInheritHandle = TRUE;
-  saAttr.lpSecurityDescriptor = NULL;
-
   /* Create a pipe for the child's STDOUT. */
-  if (! CreatePipe(&hChildStdoutRd, &hChildStdoutWr, &saAttr, 0)) return GetLastError();
+  if (! WinPipe(&hChildStdoutRd, &hChildStdoutWr)) return GetLastError();
 
   /* Create a pipe for the child's STDIN. */
-  if (! CreatePipe(&hChildStdinRd, &hChildStdinWr, &saAttr, 0)) return GetLastError();
+  if (! WinPipe(&hChildStdinRd, &hChildStdinWr)) return GetLastError();
 
   SetCurrentDirectory(dir); // go to engine directory
 
-- 
1.7.0.4