From 627bc70e0ffdf4bdf04cb1ff96c6077b5995f2e9 Mon Sep 17 00:00:00 2001
From: XANTRONIX Development <dev@xantronix.com>
Date: Fri, 22 May 2020 22:31:04 -0400
Subject: [PATCH] Show printable frame bytes in src/decode.c

---
 src/decode.c | 49 ++++++++++++++++++++++++++++++++-----------------
 1 file changed, 32 insertions(+), 17 deletions(-)

diff --git a/src/decode.c b/src/decode.c
index f6ac1f4..dda3722 100644
--- a/src/decode.c
+++ b/src/decode.c
@@ -32,42 +32,57 @@ static int callsign_fprint(FILE *stream, const patty_ax25_address *address) {
     return 0;
 }
 
+#define printable(c) \
+    (c >= 0x20 && c < 0x7f)
+
 static int hexdump_fprint(FILE *stream, void *data, size_t len) {
     size_t i;
 
-    for (i=0; i<len; i++) {
-        if (i % 16 == 0) {
-            if (i) {
-                if (fprintf(stderr, "\n") < 0) {
-                    goto error_fprintf;
+    for (i=0; i<len; i+=16) {
+        size_t x;
+
+        if (fprintf(stream, "%08lx:", i) < 0) {
+            goto error_io;
+        }
+
+        for (x=0; x<16; x++) {
+            if (!(x & 1)) {
+                if (fprintf(stream, " ") < 0) {
+                    goto error_io;
                 }
             }
 
-            if (fprintf(stderr, "%08lx: ", i) < 0) {
-                goto error_fprintf;
+            if (i+x < len) {
+                if (fprintf(stream, "%02x", ((uint8_t *)data)[i+x]) < 0) {
+                    goto error_io;
+                }
+            } else {
+                if (fprintf(stream, "  ") < 0) {
+                    goto error_io;
+                }
             }
         }
 
-        if (fprintf(stderr, "%02x", ((uint8_t *)data)[i]) < 0) {
-            goto error_fprintf;
+        if (fprintf(stream, "  ") < 0) {
+            goto error_io;
         }
 
-        if (i % 2) {
-            if (fprintf(stderr, " ") < 0) {
-                goto error_fprintf;
+        for (x=0; x<16 && i+x<len; x++) {
+            uint8_t c = ((uint8_t *)data)[i+x];
+
+            if (fputc(printable(c)? c: '.', stream) < 0) {
+                goto error_io;
             }
         }
-    }
 
-    if (i) {
-        if (fprintf(stderr, "\n") < 0) {
-            goto error_fprintf;
+        if (fprintf(stream, "\n") < 0) {
+            goto error_io;
         }
     }
 
     return 0;
 
-error_fprintf:
+error_io:
     return -1;
 }