[gegl] gegl-compression: add "nop" algorithm

[Ell <ell src gnome org>]

commit 798cb4d6717fb75385e0b3f15818c31f9464bef4
Author: Ell <ell_se yahoo com>
Date:   Mon Dec 17 04:45:39 2018 -0500

    gegl-compression: add "nop" algorithm
    
    A simple "compression" algorithm, which simply memcpy()s the data.
    Useful mostly for testing.

 gegl/buffer/Makefile.am            |  2 +
 gegl/buffer/gegl-compression-nop.c | 96 ++++++++++++++++++++++++++++++++++++++
 gegl/buffer/gegl-compression-nop.h | 30 ++++++++++++
 gegl/buffer/gegl-compression.c     |  3 ++
 4 files changed, 131 insertions(+)
---
diff --git a/gegl/buffer/Makefile.am b/gegl/buffer/Makefile.am
index 3d9ada9e2..235174cf8 100644
--- a/gegl/buffer/Makefile.am
+++ b/gegl/buffer/Makefile.am
@@ -43,6 +43,7 @@ libbuffer_la_SOURCES = \
     gegl-buffer-save.c         \
     gegl-buffer-swap.c         \
     gegl-compression.c         \
+    gegl-compression-nop.c     \
     gegl-sampler.c             \
     gegl-sampler-cubic.c       \
     gegl-sampler-linear.c      \
@@ -75,6 +76,7 @@ libbuffer_la_SOURCES = \
     gegl-buffer-swap.h         \
     gegl-buffer-swap-private.h \
     gegl-compression.h         \
+    gegl-compression-nop.h     \
     gegl-sampler.h             \
     gegl-sampler-cubic.h       \
     gegl-sampler-linear.h      \
diff --git a/gegl/buffer/gegl-compression-nop.c b/gegl/buffer/gegl-compression-nop.c
new file mode 100644
index 000000000..02e648cbe
--- /dev/null
+++ b/gegl/buffer/gegl-compression-nop.c
@@ -0,0 +1,96 @@
+/* This file is part of GEGL
+ *
+ * GEGL 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.
+ *
+ * GEGL 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 GEGL; if not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <string.h>
+
+#include "gegl-compression.h"
+#include "gegl-compression-nop.h"
+
+
+/*  local function prototypes  */
+
+static gboolean   gegl_compression_nop_compress   (const GeglCompression *compression,
+                                                   const Babl            *format,
+                                                   gconstpointer          data,
+                                                   gint                   n,
+                                                   gpointer               compressed,
+                                                   gint                  *compressed_size,
+                                                   gint                   max_compressed_size);
+static gboolean   gegl_compression_nop_decompress (const GeglCompression *compression,
+                                                   const Babl            *format,
+                                                   gpointer               data,
+                                                   gint                   n,
+                                                   gconstpointer          compressed,
+                                                   gint                   compressed_size);
+
+
+/*  private functions  */
+
+static gboolean
+gegl_compression_nop_compress (const GeglCompression *compression,
+                               const Babl            *format,
+                               gconstpointer          data,
+                               gint                   n,
+                               gpointer               compressed,
+                               gint                  *compressed_size,
+                               gint                   max_compressed_size)
+{
+  gint size = n * babl_format_get_bytes_per_pixel (format);
+
+  if (max_compressed_size < size)
+    return FALSE;
+
+  memcpy (compressed, data, size);
+
+  *compressed_size = size;
+
+  return TRUE;
+}
+
+static gboolean
+gegl_compression_nop_decompress (const GeglCompression *compression,
+                                 const Babl            *format,
+                                 gpointer               data,
+                                 gint                   n,
+                                 gconstpointer          compressed,
+                                 gint                   compressed_size)
+{
+  gint size = n * babl_format_get_bytes_per_pixel (format);
+
+  if (compressed_size != size)
+    return FALSE;
+
+  memcpy (data, compressed, size);
+
+  return TRUE;
+}
+
+
+/*  public functions  */
+
+void
+gegl_compression_nop_init (void)
+{
+  static const GeglCompression compression_nop =
+  {
+    .compress   = gegl_compression_nop_compress,
+    .decompress = gegl_compression_nop_decompress
+  };
+
+  gegl_compression_register ("nop", &compression_nop);
+}
diff --git a/gegl/buffer/gegl-compression-nop.h b/gegl/buffer/gegl-compression-nop.h
new file mode 100644
index 000000000..938c18d13
--- /dev/null
+++ b/gegl/buffer/gegl-compression-nop.h
@@ -0,0 +1,30 @@
+/* This file is part of GEGL
+ *
+ * GEGL 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.
+ *
+ * GEGL 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 GEGL; if not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef __GEGL_COMPRESSION_NOP_H__
+#define __GEGL_COMPRESSION_NOP_H__
+
+
+#include <glib.h>
+#include <babl/babl.h>
+
+G_BEGIN_DECLS
+
+void   gegl_compression_nop_init (void);
+
+G_END_DECLS
+
+#endif
diff --git a/gegl/buffer/gegl-compression.c b/gegl/buffer/gegl-compression.c
index 5e932991c..51e89177d 100644
--- a/gegl/buffer/gegl-compression.c
+++ b/gegl/buffer/gegl-compression.c
@@ -20,6 +20,7 @@
 #include <string.h>
 
 #include "gegl-compression.h"
+#include "gegl-compression-nop.h"
 
 
 /*  local variables  */
@@ -35,6 +36,8 @@ gegl_compression_init (void)
   g_return_if_fail (algorithms == NULL);
 
   algorithms = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
+
+  gegl_compression_nop_init ();
 }
 
 void