Improve our ip6_to_str_buf() implementation

Change-Id: I02b5d01797e526299a6dc5a031662cb78e4f8423
Reviewed-on: https://code.wireshark.org/review/24163
Reviewed-by: João Valverde <j@v6e.pt>

1 files changed, 28 insertions, 6 deletions

diff --git a/epan/to_str.c b/epan/to_str.c
index 4c59ef9681..c6b30c6162 100644
--- a/epan/to_str.c
+++ b/epan/to_str.c
@@ -1043,15 +1043,37 @@ ip_to_str_buf(const guint8 *ad, gchar *buf, const int buf_len)
 	*b=0;
 }
 
-void
-ip6_to_str_buf(const ws_in6_addr *ad, gchar *buf, int buf_len)
+int
+ip6_to_str_buf_with_pfx(const ws_in6_addr *addr, gchar *buf, int buf_size, const char *prefix)
 {
-	if (buf_len < WS_INET6_ADDRSTRLEN) {
-		g_strlcpy(buf, BUF_TOO_SMALL_ERR, buf_len);  /* Let the unexpected value alert user */
-		return;
+	int bytes;    /* the number of bytes which would be produced if the buffer was large enough. */
+	gchar addr_buf[WS_INET6_ADDRSTRLEN];
+	int len;
+
+	if (prefix == NULL)
+		prefix = "";
+	bytes = g_snprintf(buf, buf_size, "%s%s", prefix, ws_inet_ntop6(addr, addr_buf, sizeof(addr_buf)));
+	len = bytes - 1;
+
+	if (len > buf_size - 1) { /* size minus nul terminator */
+		len = (int)g_strlcpy(buf, BUF_TOO_SMALL_ERR, buf_size);  /* Let the unexpected value alert user */
 	}
+	return len;
+}
+
+int
+ip6_to_str_buf(const ws_in6_addr *addr, gchar *buf, int buf_size)
+{
+	gchar addr_buf[WS_INET6_ADDRSTRLEN];
+	int len;
 
-	ws_inet_ntop6(ad, buf, buf_len);
+	/* slightly more efficient than ip6_to_str_buf_with_pfx(addr, buf, buf_size, NULL) */
+	len = (int)g_strlcpy(buf, ws_inet_ntop6(addr, addr_buf, sizeof(addr_buf)), buf_size);     /* this returns len = strlen(addr_buf) */
+
+	if (len > buf_size - 1) { /* size minus nul terminator */
+		len = (int)g_strlcpy(buf, BUF_TOO_SMALL_ERR, buf_size);  /* Let the unexpected value alert user */
+	}
+	return len;
 }
 
 gchar *