add TTYavailable function

Makefile

@@ -5,4 +5,4 @@ Clean\ System\ Files/tty.o: tty.c
 	gcc -g -c $< -o "$@"
 
 clean:
-	$(RM) -r Clean\ System\ Files/* test sapl
+	$(RM) -r Clean\ System\ Files/* test

TTY.dcl

@@ -20,12 +20,9 @@ from StdClass import class zero
 
 instance zero TTYSettings
 
-TTYopen :: !String !TTYSettings !*env -> (!Bool,!*TTY,!*env)
-
 TTYclose :: !*TTY !*env -> (!Bool, !*env)
-
+TTYerror :: !*env -> (!String, !*env)
+TTYopen :: !String !TTYSettings !*env -> (!Bool,!*TTY,!*env)
 TTYreadline :: !*TTY -> (!String, !*TTY)
-
+TTYavailable :: !*TTY -> (!Bool, !*TTY)
 TTYwrite :: !*TTY !String -> *TTY
-
-TTYerror :: !*env -> (!String, !*env)

TTY.icl

@@ -46,22 +46,27 @@ TTYopen fn ts w = TTYopen2
 			}
 
 TTYclose :: !*TTY !*env -> (!Bool, !*env)
-TTYclose f w = code {
+TTYclose _ _ = code {
 		ccall ttyclose "I:I:A"
 	}
 
 TTYreadline :: !*TTY -> (!String, !*TTY)
-TTYreadline t = code {
+TTYreadline _ = code {
 		ccall ttyreadline "I:VSI"
 	}
 
 TTYwrite :: !*TTY !String -> *TTY
-TTYwrite s e = code {
+TTYwrite _ _ = code {
 		ccall ttywrite "IS:I"
 	}
 
+TTYavailable :: !*TTY -> (!Bool, !*TTY)
+TTYavailable _ = code {
+		ccall ttyavailable "I:VII"
+	}
+
 TTYerror :: !*env -> (!String, !*env)
-TTYerror w = code {
+TTYerror _ = code {
 		ccall ttyerror ":S:A"
 	}
 

test.icl

@@ -4,13 +4,23 @@ import StdEnv
 
 import TTY
 
-Start :: *World -> (!String, *World)
+TTYerrorclose :: !*File !*World -> *World
+TTYerrorclose f w
+# (err, w) = TTYerror w
+# (ok, w) = fclose (f <<< err <<< "\n") w
+| not ok = abort "Couldn't close file"
+= w
+
+Start :: *World -> *World
 Start w
-#! (ok, tty, w) = TTYopen "/dev/ttyUSB0" zero w
-| not ok = TTYerror w
+# (io, w) = stdio w
+# (ok, tty, w) = TTYopen "/dev/ttyUSB0" zero w
+| not ok = TTYerrorclose io w
 #! tty = TTYwrite tty "echo123\n"
-#! (c, tty) = TTYreadline tty
+#! (av, tty) = TTYavailable tty
+# io = io <<< ("Bytes available: " +++ toString av +++ "\n")
+#! (l, tty) = TTYreadline tty
+# io = io <<< ("Line read: " +++ l)
 #! (ok, w) = TTYclose tty w
-| not ok = TTYerror w
-#! (s, w) = TTYerror w
-= ("Read: " +++ c, w)
+| not ok = TTYerrorclose io w
+= snd (fclose io w)

tty.c

@@ -11,6 +11,7 @@
 #include "Clean.h"
 
 #define INITIAL_BUFFERSIZE 2
+#define DEVICE_TIMEOUT {5, 0}
 #define die(s) {perror(s);exit(EXIT_FAILURE);}
 
 static speed_t baudrates[] = {B0, B50, B75, B110, B134, B150, B200, B300, B600,
@@ -168,6 +169,20 @@ void ttyreadline(int fd, CleanString *result, int *fdo)
 	free(buf);
 }
 
+void ttyavailable(int fd, int *r, int *fdo)
+{
+	fd_set fds;
+	struct timeval tv = DEVICE_TIMEOUT;
+
+	FD_ZERO(&fds);
+	FD_SET(fd, &fds);
+
+	*r = select(fd+1, &fds, NULL, NULL, NULL);
+	if(*r == -1)
+		die("select");
+	*fdo = fd;
+}
+
 int ttywrite(int fd, CleanString s)
 {
 	write(fd, CleanStringCharacters(s), CleanStringLength(s));