Moved helper macro to a discrete include file.

To help reduce code duplication and also 'kitchen-sink' includes
the ARRAY_LENGTH macro was moved to a stand-alone file and
referenced from the sources consuming it. Other macros will be
added in subsequent passes.

Signed-off-by: Jon A. Cruz <jonc@osg.samsung.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>

shared/cairo-util.c

@@ -35,11 +35,10 @@
 #include <cairo.h>
 #include "cairo-util.h"
 
+#include "shared/helpers.h"
 #include "image-loader.h"
 #include "config-parser.h"
 
-#define ARRAY_LENGTH(a) (sizeof (a) / sizeof (a)[0])
-
 void
 surface_flush_device(cairo_surface_t *surface)
 {

shared/helpers.h

@@ -0,0 +1,48 @@
+/*
+ * Copyright © 2015 Samsung Electronics Co., Ltd
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+  *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef WESTON_HELPERS_H
+#define WESTON_HELPERS_H
+
+#ifdef  __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @file
+ * Simple misc helper macros.
+ */
+
+/**
+ * Compile-time computation of number of items in a hardcoded array.
+ *
+ * @param a the array being measured.
+ * @return the number of items hardcoded into the array.
+ */
+#ifndef ARRAY_LENGTH
+#define ARRAY_LENGTH(a) (sizeof (a) / sizeof (a)[0])
+#endif
+
+#ifdef  __cplusplus
+}
+#endif
+
+#endif /* WESTON_HELPERS_H */

shared/image-loader.c

@@ -34,10 +34,9 @@
 #include <png.h>
 #include <pixman.h>
 
+#include "shared/helpers.h"
 #include "image-loader.h"
 
-#define ARRAY_LENGTH(a) (sizeof (a) / sizeof (a)[0])
-
 #ifdef HAVE_WEBP
 #include <webp/decode.h>
 #endif