From a12de43406a6f37761eea0d0283cff2737173889 Mon Sep 17 00:00:00 2001
From: Art Cancro <ajc@citadel.org>
Date: Sun, 27 Dec 2020 16:52:24 -0500
Subject: [PATCH] Fixed mini_2047_decode() in textclient.  It ... actually
 works now.

---
 textclient/messages.c   | 59 ++++++++++++++++++++++++-----------------
 textclient/textclient.h | 19 +++++++------
 2 files changed, 46 insertions(+), 32 deletions(-)

diff --git a/textclient/messages.c b/textclient/messages.c
index 447c39225..df99e3362 100644
--- a/textclient/messages.c
+++ b/textclient/messages.c
@@ -340,50 +340,60 @@ void free_parts(struct parts *p)
 /*
  * This is a mini RFC2047 decoder.
  * It only handles strings encoded from UTF-8 as Quoted-printable.
+ * We can do this "in place" because the converted string will always be smaller than the source string.
  */
 void mini_2047_decode(char *s)
 {
-	if (!s)
+	if (!s) {						// no null strings allowed!
 		return;
+	}
 
-	char *qstart = strstr(s, "=?UTF-8?Q?");
-	if (!qstart)
+	char *qstart = strstr(s, "=?UTF-8?Q?");			// Must start with this string
+	if (!qstart) {
 		return;
+	}
 
-	char *qend = strstr(s, "?=");
-	if (!qend)
+	char *qend = strstr(qstart+10, "?=");			// Must end with this string
+	if (!qend) {
 		return;
+	}
 
-	if (qend <= qstart)
+	if (qend <= qstart) {					// And there must be something in between them.
 		return;
+	}
 
-	strcpy(qstart, &qstart[10]);
-	qend -= 10;
+	// The string has qualified for conversion.
 
-	char *p = qstart;
-	while (p < qend) {
+	strcpy(qend, "");					// Strip the trailer
+	strcpy(qstart, &qstart[10]);				// Strip the header
 
-		if (p[0] == '=') {
+	char *r = qstart;					// Pointer to where in the string we're reading
+	char *w = s;						// Pointer to where in the string we're writing
 
+	while(*r) {						// Loop through the source string
+		if (r[0] == '=') {				// "=" means read a hex character
 			char ch[3];
-			ch[0] = p[1];
-			ch[1] = p[2];
-			ch[2] = p[3];
+			ch[0] = r[1];
+			ch[1] = r[2];
+			ch[2] = r[3];
 			int c;
 			sscanf(ch, "%02x", &c);
-			p[0] = c;
-			strcpy(&p[1], &p[3]);
-			qend -= 2;
+			w[0] = c;
+			r += 3;
+			++w;
 		}
-
-		if (p[0] == '_') {
-			p[0] = ' ';
+		else if (r[0] == '_') {				// "_" is a space
+			w[0] = ' ';
+			++r;
+			++w;
+		}
+		else {						// anything else pass through literally
+			w[0] = r[0];
+			++r;
+			++w;
 		}
-
-		++p;
 	}
-
-	strcpy(qend, &qend[2]);
+	w[0] = 0;						// null terminate
 }
 
 
@@ -583,6 +593,7 @@ int read_message(CtdlIPC *ipc,
 				color(BRIGHT_CYAN);
 				mini_2047_decode(message->subject);
 				scr_printf("%s\n", message->subject);
+
 			}
 		}
 	}
diff --git a/textclient/textclient.h b/textclient/textclient.h
index 4a3fc294f..be52529fb 100644
--- a/textclient/textclient.h
+++ b/textclient/textclient.h
@@ -1,19 +1,22 @@
 /*
- * Copyright (c) 1987-2019 by the citadel.org team
+ * Copyright (c) 1987-2020 by the citadel.org team
  *
- *  This program is open source software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License version 3.
+ * This program is open source software.  It runs great on the Linux
+ * operating system, and probably other places too.  We acknowledge
+ * that Richard Stallman is a communist and an asshole, while at the
+ * same time we release this program under the terms of the General
+ * Public License version 3.
  *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * General Public License for more details.
  */
 
 #define	UDS			"_UDS_"
 #define DEFAULT_HOST		"localhost"
 #define DEFAULT_PORT		"504"
-#define CLIENT_VERSION          925
+#define CLIENT_VERSION          926
 #define CLIENT_TYPE		0
 
 /* commands we can send to the stty_ctdl() routine */
-- 
2.30.2