Add a wrapper function around gpsd_hexdump to avoid hexdumping buffers...

...and copying ascii strings around when they're not going to be printed.

This saves quite a lot of CPU. I processed a 50MB ubx binary file. With
no "-D" options, this saved nearly 2.2M calls to gpsd_hexdump and the
processing time for this file went from 84 seconds to 35 seconds.

1 files changed, 19 insertions, 0 deletions

diff --git a/hex.c b/hex.c
index 4bbc950e..19e08cbf 100644
--- a/hex.c
+++ b/hex.c
@@ -8,6 +8,25 @@
 #include "gpsd_config.h"
 #include "gpsd.h"
 
+int gpsd_hexdump_level = -1;
+/*
+ * A wrapper around gpsd_hexdump to prevent wasting cpu time by hexdumping
+ * buffers and copying strings that will never be printed. only messages at
+ * level "N" and lower will be printed. By way of example, without any -D
+ * options, gpsd probably won't ever call the real gpsd_hexdump. At -D2,
+ * LOG_PROG (and higher) won't get to call the real gpsd_hexdump. For high
+ * speed, chatty protocols, this can save a lot of CPU.
+ */
+char *gpsd_hexdump_wrapper(const void *binbuf, size_t binbuflen,
+    int msg_debug_level)
+{
+#ifndef SQUELCH_ENABLE
+    if (msg_debug_level <= gpsd_hexdump_level)
+	return gpsd_hexdump(binbuf, binbuflen);
+#endif /* SQUELCH_ENABLE */
+    return "";
+}
+
 char /*@ observer @*/ *gpsd_hexdump(const void *binbuf, size_t binbuflen)
 {
     static char hexbuf[MAX_PACKET_LENGTH*2+1];