More development ...

Tools/Construct/Parallel/client.cxx

@@ -53,7 +53,7 @@ int make_socket (char *host, unsigned short int port) {
 
 
 // connect to the server and get the next task
-long int get_next_task( const string& host, int port ) {
+long int get_next_task( const string& host, int port, long int last_tile ) {
     long int tile;
     int sock, len;
     fd_set ready;
@@ -65,29 +65,29 @@ long int get_next_task( const string& host, int port ) {
     }
 
     // build a command string from the argv[]'s
-    strcpy(message, "hello world!\n");
+    sprintf(message, "%ld", last_tile);
 
     // send command and arguments to remote server
-    // if ( write(sock, message, sizeof(message)) < 0 ) {
-    //    perror("Cannot write to stream socket");
-    // }
+    if ( write(sock, message, sizeof(message)) < 0 ) {
+        perror("Cannot write to stream socket");
+    }
 
     // loop until remote program finishes
-    cout << "looping ..." << endl;
+    cout << "querying server for next task ..." << endl;
 
     FD_ZERO(&ready);
     FD_SET(sock, &ready);
 
     // block until input from sock
     select(32, &ready, 0, 0, NULL);
-    cout << "unblocking ... " << endl;
+    cout << " received reply" << endl;
 
     if ( FD_ISSET(sock, &ready) ) {
 	/* input coming from socket */
 	if ( (len = read(sock, message, 1024)) > 0 ) {
 	    message[len] = '\0';
 	    tile = atoi(message);
-	    cout << "tile to construct = " << tile << endl;
+	    cout << "  tile to construct = " << tile << endl;
 	    close(sock);
 	    return tile;
 	} else {
@@ -101,13 +101,16 @@ long int get_next_task( const string& host, int port ) {
 }
 
 
-// build the specified tile
-void run_task( long int tile ) {
+// build the specified tile, return true if contruction completed
+// successfully
+bool construct_tile( long int tile ) {
+    return true;
 }
 
 
 main(int argc, char *argv[]) {
-    long int tile;
+    long int tile, last_tile;
+    bool result;
 
     // Check usage
     if ( argc < 3 ) {
@@ -118,10 +121,15 @@ main(int argc, char *argv[]) {
     string host = argv[1];
     int port = atoi( argv[2] );
 
-    while ( 
-	   (tile = get_next_task( host, port )) >= 0
-	   )
-    {
-	run_task( tile );
+    last_tile = 0;
+
+    while ( (tile = get_next_task( host, port, last_tile )) >= 0 ) {
+	result = construct_tile( tile );
+
+	if ( result ) {
+	    last_tile = tile;
+	} else {
+	    last_tile = -tile;
+	}
     }
 }

Tools/Construct/Parallel/server.cxx

@@ -59,7 +59,6 @@ int make_socket (unsigned short int* port) {
 }
 
 
-#if 0 // better move this to client
 // return true if file exists
 static bool file_exists( const string& file ) {
     struct stat buf;
@@ -87,7 +86,7 @@ static bool has_data( const string& path, const FGBucket& b ) {
 
     return false;
 }
-#endif
+
 
 // initialize the tile counting system
 void init_tile_count() {
@@ -131,7 +130,8 @@ long int get_next_tile( const string& work_base, const string& output_base )
 	}
 
 	// reset lat
-	lat = -89.0 + (shift_up*dy) - (dy*0.5);
+	// lat = -89.0 + (shift_up*dy) - (dy*0.5);
+	lat = 0.0 + (shift_up*dy) + (dy*0.5);
 
 	// reset lon
 	FGBucket tmp( 0.0, lat );
@@ -216,7 +216,11 @@ int main( int argc, char **argv ) {
 	    // printf("%d %d Incomming message --> ", getpid(), pid);
 
 	    // get the next tile to work on
-	    next_tile = get_next_tile(work_base, output_base);
+	    next_tile = get_next_tile( work_base, output_base );
+	    while ( ! has_data( work_base, FGBucket(next_tile) ) ) {
+		next_tile = get_next_tile( work_base, output_base );
+	    }
+
 	    // cout << "next tile = " << next_tile << endl;;
 
 	    msgsock = accept(sock, 0, 0);
@@ -236,7 +240,8 @@ int main( int argc, char **argv ) {
 		// clean up all of our zombie children
 		int status;
 		while ( (pid = waitpid( WAIT_ANY, &status, WNOHANG )) > 0 ) {
-		    // cout << "waitpid() returned " << pid << endl;
+		    cout << "waitpid(): pid = " << pid 
+			 << " status = " << status << endl;
 		}
 	    } else {
 		// This is the child
@@ -244,6 +249,17 @@ int main( int argc, char **argv ) {
 		// cout << "new process started to handle new connection for "
 		//      << next_tile << endl;
 
+                // Read client's command
+		char buf[MAXBUF];
+                if ( (length = read(msgsock, buf, MAXBUF)) < 0) {
+                    perror("Cannot read command");
+                    exit(-1);
+                }
+
+		buf[length] = '\0';
+		long int returned_tile = atoi(buf);
+		cout << "client replied with " << returned_tile << endl;
+
 		// reply to the client
 		char message[MAXBUF];
 		sprintf(message, "%ld", next_tile);
@@ -254,7 +270,7 @@ int main( int argc, char **argv ) {
 		close(msgsock);
 		// cout << "process for " << next_tile << " ended" << endl;
 
-		exit(0);
+		exit(returned_tile);
 	    }
 	}
     }