util: Add SSID to UTF8 pretty-print function

Use a static buffer for converting an SSID to an approximate string in
UTF8. Replace each char that is not UTF8 compatible with the UTF8
replacement symbol.

Makefile.am

@@ -60,7 +60,8 @@ monitor_iwmon_SOURCES = monitor/main.c linux/nl80211.h \
 					monitor/nlmon.h monitor/nlmon.c \
 					monitor/pcap.h monitor/pcap.c \
 					monitor/display.h monitor/display.c \
-					src/ie.h src/ie.c
+					src/ie.h src/ie.c \
+					src/util.h src/util.c
 monitor_iwmon_LDADD = ell/libell-internal.la
 
 noinst_PROGRAMS = tools/hwsim

src/util.c

@@ -0,0 +1,76 @@
+/*
+ *
+ *  Wireless daemon for Linux
+ *
+ *  Copyright (C) 2014  Intel Corporation. All rights reserved.
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library 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
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <string.h>
+
+#include <ell/string.h>
+
+#include "util.h"
+
+const char *util_ssid_to_utf8(size_t len, const uint8_t *ssid)
+{
+	static char buf[3* 32 + 1];
+	size_t i = 0, pos = 0;
+	const uint8_t *start = ssid, *end;
+
+	memset(buf, 0, sizeof(buf));
+
+	if (len > 32)
+		goto no_ssid;
+
+	while (i < len && !ssid[i])
+		i++;
+
+	if (i == len)
+		goto no_ssid;
+
+	i = len;
+
+	while (i && (!l_utf8_validate((const char *)start, i,
+						(const char **)&end))) {
+		const char replacement[] = { 0xEF, 0xBF, 0xBD };
+		int bytes = end - start;
+
+		memcpy(&buf[pos], start, bytes);
+		pos += bytes;
+
+		memcpy(&buf[pos], replacement, sizeof(replacement));
+		pos += sizeof(replacement);
+
+		start = end + 1;
+		i -= (bytes + 1);
+	}
+
+	if (i) {
+		memcpy(&buf[pos], start, i);
+		pos += i;
+	}
+
+no_ssid:
+	buf[pos] = '\0';
+
+	return buf;
+}

src/util.h

@@ -0,0 +1,31 @@
+/*
+ *
+ *  Wireless daemon for Linux
+ *
+ *  Copyright (C) 2013-2014  Intel Corporation. All rights reserved.
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library 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
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifndef __UTIL_H
+#define __UTIL_H
+
+#include <stdint.h>
+#include <unistd.h>
+
+const char *util_ssid_to_utf8(size_t len, const uint8_t *ssid);
+
+#endif /* __UTIL_H */