[libchamplain] Replace pow() with bit shift to be sure we are fast

[Pierre-Luc Beaudoin <plbeaudoin src gnome org>]

commit 6ef07ebbfd4e256d116878470ffe339620932918
Author: JiÅ?í Techet <techet gmail com>
Date:   Mon Mar 15 01:02:29 2010 +0100

    Replace pow() with bit shift to be sure we are fast
    
    Signed-off-by: JiÅ?í Techet <techet gmail com>

 champlain/champlain-map-source.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/champlain/champlain-map-source.c b/champlain/champlain-map-source.c
index 613fe45..c3dc82e 100644
--- a/champlain/champlain-map-source.c
+++ b/champlain/champlain-map-source.c
@@ -559,7 +559,7 @@ champlain_map_source_get_row_count (ChamplainMapSource *map_source,
 
   //ChamplainMapSourcePrivate *priv = map_source->priv;
   // FIXME: support other projections
-  return pow (2, zoom_level);
+  return (zoom_level != 0) ? 2 << (zoom_level - 1) : 1;
 }
 
 /**
@@ -582,7 +582,7 @@ champlain_map_source_get_column_count (ChamplainMapSource *map_source,
 
   //ChamplainMapSourcePrivate *priv = map_source->priv;
   // FIXME: support other projections
-  return pow (2, zoom_level);
+  return (zoom_level != 0) ? 2 << (zoom_level - 1) : 1;
 }
 
 #define EARTH_RADIUS 6378137.0 /* meters, Equatorial radius */