don't return NULL when passed a NULL pointer or a zero-length buffer;

instead, return an empty string. this sort of thing happens when we
call gpsd_hexdump inside one of the packet writers when we are about
to write a packet with no payload. Printing a NULL pointer is rather
ugly... printing an empty string is much prettier and consistent with
the SQUELCH case.

1 files changed, 2 insertions, 2 deletions

diff --git a/hex.c b/hex.c
index cc22da79..4bbc950e 100644
--- a/hex.c
+++ b/hex.c
@@ -17,8 +17,8 @@ char /*@ observer @*/ *gpsd_hexdump(const void *binbuf, size_t binbuflen)
     const char *ibuf = (const char *)binbuf;
     const char *hexchar = "0123456789abcdef";
 
-    if (NULL == binbuf)
-	return NULL;
+    if (NULL == binbuf || 0 == binbuflen) 
+	return "";
 
     /*@ -shiftimplementation @*/
     for (i = 0; i < len; i++) {