[gegl] downscale_2x2_u8 move switch out of scanline loops

[Øyvind Kolås <ok src gnome org>]

commit 38294f96ef8d5e76b84826243e32cd2cafd9513c
Author: Øyvind Kolås <pippin gimp org>
Date:   Mon Apr 2 18:05:25 2018 +0200

    downscale_2x2_u8 move switch out of scanline loops

 gegl/gegl-algorithms.c |   20 ++++++--------------
 1 files changed, 6 insertions(+), 14 deletions(-)
---
diff --git a/gegl/gegl-algorithms.c b/gegl/gegl-algorithms.c
index d5304a3..a698335 100644
--- a/gegl/gegl-algorithms.c
+++ b/gegl/gegl-algorithms.c
@@ -692,14 +692,13 @@ gegl_downscale_2x2_u8_nl (const Babl *format,
   if (!src_data || !dst_data)
     return;
 
-  for (y = 0; y < src_height / 2; y++)
-    {
-      gint    x;
-      guchar *src = src_data + src_rowstride * y * 2;
-      guchar *dst = dst_data + dst_rowstride * y;
-
 #define CASE(case_val, ...) \
 case case_val: \
+  for (y = 0; y < src_height / 2; y++) \
+    { \
+      gint    x; \
+      guchar *src = src_data + src_rowstride * y * 2; \
+      guchar *dst = dst_data + dst_rowstride * y; \
   for (x = 0; x < src_width / 2; x++)\
     {\
       uint8_t * aa = ((uint8_t *)(src));\
@@ -710,6 +709,7 @@ case case_val: \
       dst += bpp;\
       src += bpp * 2;\
     }\
+   }\
 break;\
 
       switch (components)
@@ -767,7 +767,6 @@ break;\
                                 lut_u8_to_u16[ba[i]] +
                                 lut_u8_to_u16[bb[i]])>>2 ];);
       }
-  }
 }
 
 static void
@@ -787,12 +786,6 @@ gegl_downscale_2x2_u8_nl_alpha (const Babl *format,
   if (!src_data || !dst_data)
     return;
 
-  for (y = 0; y < src_height / 2; y++)
-    {
-      gint    x;
-      guchar *src = src_data + src_rowstride * y * 2;
-      guchar *dst = dst_data + dst_rowstride * y;
-
       switch (components)
       {
         CASE(2,
@@ -825,7 +818,6 @@ gegl_downscale_2x2_u8_nl_alpha (const Babl *format,
                                 lut_u8_to_u16[bb[i]])>>2 ];
             ((uint8_t *)dst)[components-1] = (aa[components-1] + ab[components-1] + ba[components-1] + 
bb[components-1])>>2;);
       }
-  }
 #undef CASE
 }