[babl] extensions/16bit: add a couple 16 bit alpha adding fast paths

[Øyvind Kolås <ok src gnome org>]

commit 13b1adcf7f2d70a52f872d39776c60f077c53c7a
Author: Øyvind Kolås <pippin gimp org>
Date:   Thu Dec 8 20:03:27 2016 +0100

    extensions/16bit: add a couple 16 bit alpha adding fast paths

 extensions/16bit.c     |  103 ++++++++++++++++++++++++++++++++++++++++++++++++
 extensions/Makefile.am |    1 +
 2 files changed, 104 insertions(+), 0 deletions(-)
---
diff --git a/extensions/16bit.c b/extensions/16bit.c
new file mode 100644
index 0000000..96701ef
--- /dev/null
+++ b/extensions/16bit.c
@@ -0,0 +1,103 @@
+/* babl - dynamically extendable universal pixel conversion library.
+ * Copyright (C) 2016, Øyvind Kolås.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General
+ * Public License along with this library; if not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+#include <stdio.h>
+#include <stdint.h>
+
+#include "babl.h"
+
+#include "base/util.h"
+#include "extensions/util.h"
+
+static inline long
+conv_rgbu16_rgbau16 (unsigned char *src, 
+                     unsigned char *dst, 
+                     long           samples)
+
+
+{
+  uint16_t *src16 = (uint16_t*) src;
+  uint16_t *dst16 = (uint16_t*) dst;
+  long n = samples;
+
+  while (n--)
+    {
+      *dst16++ = *src16++;
+      *dst16++ = *src16++;
+      *dst16++ = *src16++;
+      *dst16++ = 0xffff;
+    }
+
+  return samples;
+}
+
+static inline long
+conv_yu16_yau16 (unsigned char *src, 
+                 unsigned char *dst, 
+                 long           samples)
+
+
+{
+  uint16_t *src16 = (uint16_t*) src;
+  uint16_t *dst16 = (uint16_t*) dst;
+  long n = samples;
+
+  while (n--)
+    {
+      *dst16++ = *src16++;
+      *dst16++ = 0xffff;
+    }
+
+  return samples;
+}
+
+int init (void);
+
+int
+init (void)
+{
+  babl_conversion_new (
+    babl_format ("R'G'B' u16"),
+    babl_format ("R'G'B'A u16"),
+    "linear",
+    conv_rgbu16_rgbau16,
+    NULL);
+
+  babl_conversion_new (
+    babl_format ("Y' u16"),
+    babl_format ("Y'A u16"),
+    "linear",
+    conv_yu16_yau16,
+    NULL);
+
+  babl_conversion_new (
+    babl_format ("RGB u16"),
+    babl_format ("RGBA u16"),
+    "linear",
+    conv_rgbu16_rgbau16,
+    NULL);
+
+  babl_conversion_new (
+    babl_format ("Y u16"),
+    babl_format ("YA u16"),
+    "linear",
+    conv_yu16_yau16,
+    NULL);
+  return 0;
+}
diff --git a/extensions/Makefile.am b/extensions/Makefile.am
index 0aeb9b7..923ddad 100644
--- a/extensions/Makefile.am
+++ b/extensions/Makefile.am
@@ -15,6 +15,7 @@ AM_CPPFLAGS = \
 
 extdir = $(libdir)/babl-@BABL_API_VERSION@
 ext_LTLIBRARIES = \
+       16bit.la        \
        cairo.la        \
        CIE.la          \
     float-half.la   \