From 8ffcc187e9b0697d457ca978a711a3e6d72f87d1 Mon Sep 17 00:00:00 2001
From: Oliver Hartkopp <socketcan@hartkopp.net>
Date: Sat, 22 Jan 2022 14:51:20 +0100
Subject: [PATCH] cansniffer: make ASCII output switchable in CAN FD mode

In CAN FD mode the length of the output line becomes very long.
Therefore disable the ASCII output in CAN FD mode by default but
make it switchable with a new '@' command in interactive input mode.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
---
 cansniffer.c | 57 +++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 39 insertions(+), 18 deletions(-)

diff --git a/cansniffer.c b/cansniffer.c
index 9b60424..0895114 100644
--- a/cansniffer.c
+++ b/cansniffer.c
@@ -126,6 +126,7 @@ static int idx;
 static int running = 1;
 static int clearscreen = 1;
 static int print_eff;
+static int print_ascii = 1;
 static int notch;
 static int max_dlen = CAN_MAX_DLEN;
 static long timeout = TIMEOUT;
@@ -179,6 +180,7 @@ void print_usage(char *prg)
 		" 8<ENTER>        - toggle binary / HEX-ASCII output (small for EFF on 80 chars)\n"
 		" B<ENTER>        - toggle binary with gap / HEX-ASCII output (exceeds 80 chars!)\n"
 		" c<ENTER>        - toggle color mode\n"
+		" @<ENTER>        - toggle ASCII output (disabled for CAN FD by default)\n"
 		" <SPACE><ENTER>  - force a clear screen\n"
 		" #<ENTER>        - notch currently marked/changed bits (can be used repeatedly)\n"
 		" *<ENTER>        - clear notched marked\n"
@@ -376,6 +378,7 @@ int main(int argc, char **argv)
 		/* might be changed in CANFD_AUTO mode */
 		max_dlen = CANFD_MAX_DLEN;
 		name_sep = FD_SEP;
+		print_ascii = 0; /* don't print ASCII for CAN FD by default */
 	}
 
 	ret = bind(s, (struct sockaddr *)&addr, sizeof(addr));
@@ -537,6 +540,11 @@ int handle_keyb(void)
 		running = 0;
 		break;
 
+	case '@' :
+		/* toggle ASCII output */
+		print_ascii ^= 1;
+		break;
+
 	case 'B' :
 		binary_gap = 1;
 		switchvdl(LDL);
@@ -614,9 +622,10 @@ int handle_frame(int fd, long currcms)
 	if (canfd_mode == CANFD_AUTO) {
 		if (nbytes == CAN_MTU) {
 			canfd_mode = CANFD_OFF;
-			/* change back auto defaults */
+			/* change back auto defaults for Classical CAN */
 			max_dlen = CAN_MAX_DLEN;
 			name_sep = CC_SEP;
+			print_ascii = 1;
 		} else {
 			canfd_mode = CANFD_ON;
 		}
@@ -798,32 +807,44 @@ void print_snifline(int slot)
 			if (binary_gap)
 				putchar(' ');
 		}
-	} else {
+
+	} else { /* not binary -> hex data and ASCII output */
+
 		for (i = 0; i < sniftab[slot].current.len; i++)
 			if ((color) && (sniftab[slot].marker.data[i] & ~sniftab[slot].notch.data[i]))
 				printf("%s%02X%s ", ATTCOLOR, sniftab[slot].current.data[i], ATTRESET);
 			else
 				printf("%02X ", sniftab[slot].current.data[i]);
 
-		if (sniftab[slot].current.len < max_dlen)
-			printf("%*s", (max_dlen - sniftab[slot].current.len) * 3, "");
+		if (print_ascii) {
+			/* jump to common start for ASCII output */
+			if (sniftab[slot].current.len < max_dlen)
+				printf("%*s", (max_dlen - sniftab[slot].current.len) * 3, "");
 
-		for (i = 0; i<sniftab[slot].current.len; i++)
-			if ((sniftab[slot].current.data[i] > 0x1F) &&
-			    (sniftab[slot].current.data[i] < 0x7F))
-				if ((color) && (sniftab[slot].marker.data[i] & ~sniftab[slot].notch.data[i]))
-					printf("%s%c%s", ATTCOLOR, sniftab[slot].current.data[i], ATTRESET);
+			for (i = 0; i < sniftab[slot].current.len; i++)
+				if ((sniftab[slot].current.data[i] > 0x1F) &&
+				    (sniftab[slot].current.data[i] < 0x7F))
+					if ((color) && (sniftab[slot].marker.data[i] & ~sniftab[slot].notch.data[i]))
+						printf("%s%c%s", ATTCOLOR, sniftab[slot].current.data[i], ATTRESET);
+					else
+						putchar(sniftab[slot].current.data[i]);
 				else
-					putchar(sniftab[slot].current.data[i]);
-			else
-				putchar('.');
+					putchar('.');
 
-		/*
-		 * when the len decreased (dlc_diff > 0),
-		 * we need to blank the former data printout
-		 */
-		for (i = 0; i < dlc_diff; i++)
-			putchar(' ');
+			/*
+			 * when the len decreased (dlc_diff > 0),
+			 * we need to blank the former data printout
+			 */
+			for (i = 0; i < dlc_diff; i++)
+				putchar(' ');
+		} else {
+			/*
+			 * when the len decreased (dlc_diff > 0),
+			 * we need to blank the former data printout
+			 */
+			for (i = 0; i < dlc_diff; i++)
+				printf("   ");
+		}
 	}
 
 	putchar('\n');