--- samples/dcraw_emu.cpp.orig	2011-01-08 14:57:51.035369931 +0700
+++ samples/dcraw_emu.cpp	2011-01-08 15:33:55.222297533 +0700
@@ -390,9 +390,13 @@
             if(use_timing)
                 timerprint("LibRaw::dcraw_process()",argv[arg]);
 
-            snprintf(outfn,sizeof(outfn),
-                     "%s.%s",
-                     argv[arg], OUT.output_tiff ? "tiff" : (P1.colors>1?"ppm":"pgm"));
+            strncpy(outfn, argv[arg], sizeof(outfn));
+            char *dotp = strrchr(outfn, '.');
+            if (!dotp)
+                dotp = outfn + strlen(outfn);
+
+            snprintf(dotp, sizeof(outfn) - (dotp - outfn), ".%s",
+                OUT.output_tiff ? "tiff" : (P1.colors > 1 ? "ppm" : "pgm"));
 
             if(verbosity)
                 {