[retro-gtk/wip/aplazas/memory-size] retro-core: Support partially setting memory regions

[Adrien Plazas <aplazas src gnome org>]

commit da03a153003901c6e2e8d9392f0f6bce75645628
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Mon Sep 11 16:35:36 2017 +0200

    retro-core: Support partially setting memory regions
    
    When a memory region is set with less data than expected, fill the rest
    with zeros instead of failing.
    
    This helps supporting Libretro cores with fluctuating memory sizes.

 retro-gtk/retro-core.c |   11 ++++++++++-
 1 files changed, 10 insertions(+), 1 deletions(-)
---
diff --git a/retro-gtk/retro-core.c b/retro-gtk/retro-core.c
index e84d750..d925c85 100644
--- a/retro-gtk/retro-core.c
+++ b/retro-gtk/retro-core.c
@@ -1044,7 +1044,16 @@ retro_core_set_memory (RetroCore       *self,
   retro_core_pop_cb_data ();
 
   g_return_if_fail (memory_region != NULL);
-  g_return_if_fail (memory_region_size == length);
+  g_return_if_fail (memory_region_size >= length);
+
+  if (memory_region_size != length)
+    g_debug ("%s expects %"G_GSIZE_FORMAT" bytes for memory region %d: %d bytes"
+             " were passed. The excess will be filled with zeros.",
+             retro_core_get_name (self),
+             memory_region_size,
+             id,
+             length);
 
   memcpy (memory_region, data, length);
+  memset (memory_region + length, 0, memory_region_size - length);
 }