From 24a76ef4393391ce719da4efc40f01ce968fc751 Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Tue, 19 Dec 2000 20:33:06 +0000
Subject: [PATCH] don't seek while backing up over demotime. gzipped demos no
 longer slow down as the demo progresses (this will probably also be good for
 eventual dzip support).

---
 source/cl_demo.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/source/cl_demo.c b/source/cl_demo.c
index e9285e3..b68f9ed 100644
--- a/source/cl_demo.c
+++ b/source/cl_demo.c
@@ -175,10 +175,17 @@ CL_GetDemoMessage (void)
 	float       demotime;
 	byte        c;
 	usercmd_t  *pcmd;
+	static int  demotime_cached;
+	static float cached_demotime;
 
 	// read the time from the packet
-	Qread (cls.demofile, &demotime, sizeof (demotime));
-	demotime = LittleFloat (demotime);
+	if (demotime_cached) {
+		demotime = cached_demotime;
+		demotime_cached = 0;
+	} else {
+		Qread (cls.demofile, &demotime, sizeof (demotime));
+		demotime = LittleFloat (demotime);
+	}
 
 // decide if it is time to grab the next message        
 	if (cls.timedemo) {
@@ -187,8 +194,8 @@ CL_GetDemoMessage (void)
 		else if (demotime > cls.td_lastframe) {
 			cls.td_lastframe = demotime;
 			// rewind back to time
-			Qseek (cls.demofile, Qtell (cls.demofile) - sizeof (demotime),
-				   SEEK_SET);
+			demotime_cached = 1;
+			cached_demotime = demotime;
 			return 0;					// allready read this frame's message
 		}
 		if (!cls.td_starttime && cls.state == ca_active) {
@@ -203,13 +210,13 @@ CL_GetDemoMessage (void)
 			// too far back
 			realtime = demotime - 1.0;
 			// rewind back to time
-			Qseek (cls.demofile, Qtell (cls.demofile) - sizeof (demotime),
-				   SEEK_SET);
+			demotime_cached = 1;
+			cached_demotime = demotime;
 			return 0;
 		} else if (realtime < demotime) {
 			// rewind back to time
-			Qseek (cls.demofile, Qtell (cls.demofile) - sizeof (demotime),
-				   SEEK_SET);
+			demotime_cached = 1;
+			cached_demotime = demotime;
 			return 0;					// don't need another message yet
 		}
 	} else