[gegl] gegl/buffer: make nearest sampler able to use memcpy

[Øyvind Kolås <ok src gnome org>]

commit c0d3ce82a2e74343179ae4e6a4ef4a257ca7a5ef
Author: Øyvind Kolås <pippin gimp org>
Date:   Tue Jan 9 16:53:52 2018 +0100

    gegl/buffer: make nearest sampler able to use memcpy
    
    Using memcpy directly should be lower overhead than invoking a fish for a
    single pixel when pixelformats match.

 gegl/buffer/gegl-sampler-nearest.c |   11 ++++++-----
 1 files changed, 6 insertions(+), 5 deletions(-)
---
diff --git a/gegl/buffer/gegl-sampler-nearest.c b/gegl/buffer/gegl-sampler-nearest.c
index ccd0a94..eb496a7 100644
--- a/gegl/buffer/gegl-sampler-nearest.c
+++ b/gegl/buffer/gegl-sampler-nearest.c
@@ -184,9 +184,12 @@ gegl_sampler_get_pixel (GeglSampler    *sampler,
         gint       offsetx = tiledx - tile_origin_x;
         gint       offsety = tiledy - tile_origin_y;
 
-        guchar *tp         = gegl_tile_get_data (tile) + (offsety * tile_width + offsetx) * 
nearest_sampler->buffer_bpp;
+        guchar *tp = gegl_tile_get_data (tile) + (offsety * tile_width + offsetx) * 
nearest_sampler->buffer_bpp;
 
-        babl_process (sampler->fish, tp, buf, 1);
+        if (sampler->fish)
+          babl_process (sampler->fish, tp, buf, 1);
+        else
+          memcpy (buf, tp, nearest_sampler->buffer_bpp);
       }
   }
 
@@ -237,13 +240,11 @@ gegl_sampler_nearest_prepare (GeglSampler* restrict sampler)
     return;
   GEGL_SAMPLER_NEAREST (sampler)->buffer_bpp = babl_format_get_bytes_per_pixel (sampler->buffer->format);
 
-#if 0 // maybe re-enable; when certain result is correct
   if (sampler->format == sampler->buffer->soft_format)
     {
-      sampler->get = gegl_sampler_nearest_get_same_format;
+      sampler->fish = NULL;
     }
   else
-#endif
     {
       sampler->fish = babl_fish (sampler->buffer->soft_format, sampler->format);
     }