the proposal of enhanced read() call

[Petr Stehlik <stehlik@cas3.zlin.vutbr.cz>]

   Hi,

when patching NCurses to work under single TOS I encountered the problem
with function keys - I needed to send a scan-code from read() call to the
NCurses library. I have developed something which doesn't look too well
but it actually works. The idea is to send an ESCape code as a beginning
of ESCape sequence (like it works with termcap under MiNT, for example). 
Now I am thinking about patching the read() call much more to allow proper
sending of Shifted function keys (e.g. shift-down_arrow)...

The current solution is however good enough to distinguish the arrow keys,
Help, Undo, Home key and all 20 function keys under NCurses...

Comments on the patch are welcome.

--- read.c	Mon Feb 14 23:48:10 1994
+++ /usr/src/libsrc/read.c	Sat Jun  7 06:24:26 1997
@@ -39,6 +39,8 @@
  * work properly
  */
 
+static int scancode = -1;
+
 long
 _read(fd, buf, size)
 	int fd;
@@ -137,8 +139,18 @@
 		}
 	}
 	else {
+		long key;
 again:
-		r = _console_read_byte(fd) & 0x00ff;
+		if (scancode > 0 && size == 1) {	/* valid scan-code? */
+			*((char *)buf) = scancode;
+			scancode = -1;				/* invalidate scan-code */
+			return 1;
+		}
+
+		key = _console_read_byte(fd);
+		r = key & 0x00ff;	/* r = ASCII code */
+		key >>= 16;			/* key = scan-code */
+
 		if (flags & ECHO) {
 			_console_write_byte(fd, (int)r);
 		}
@@ -155,8 +167,21 @@
 				goto again;
 			}
 		}
-		*((char *)buf) = r;
-		r = 1;
+		if (r != 0) {
+			*((char *)buf) = r;
+			r = 1;
+		}
+		else {
+			*((char *)buf) = '\034';	/* indicates that a scan-code follows */
+			if (size > 1) {
+				*((char *)buf+1) = key;	/* put scan-code to buffer */
+				r = 2;
+			}
+			else {
+				scancode = key & 0x00ff;/* valid scan-code for next read() call */
+				r = 1;
+			}
+		}
 	}
 
 	return r;

Petr
--
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