[Bf-blender-cvs] [724a4f46765] master: Fix T81226: Crash opening 64bit files with endian switching

[Campbell Barton]

Commit: 724a4f4676586d65b718deab7f04f207e0ad6488
Author: Campbell Barton
Date:   Wed Oct 7 21:48:59 2020 +1100
Branches: master
https://developer.blender.org/rB724a4f4676586d65b718deab7f04f207e0ad6488

Fix T81226: Crash opening 64bit files with endian switching

Endian switching when loading 64bit blend files on a 64bit system was
crashing as the endian switching is only applicable when loading
on 32 bit systems.

This crash goes back to 2.7x, it looks like this never worked
all the way back to the first commit.

===================================================================

M	source/blender/makesdna/intern/dna_genfile.c

===================================================================

diff --git a/source/blender/makesdna/intern/dna_genfile.c b/source/blender/makesdna/intern/dna_genfile.c
index 511f9f354c9..d7360c67210 100644
--- a/source/blender/makesdna/intern/dna_genfile.c
+++ b/source/blender/makesdna/intern/dna_genfile.c
@@ -1030,8 +1030,12 @@ void DNA_struct_switch_endian(const SDNA *oldsdna, int oldSDNAnr, char *data)
     else {
       /* non-struct field type */
       if (ispointer(name)) {
-        if (oldsdna->pointer_size == 8) {
-          BLI_endian_switch_int64_array((int64_t *)cur, old_name_array_len);
+        /* See readfile.c (#bh4_from_bh8 swap endian argument),
+         * this is only done when reducing the size of a pointer from 4 to 8. */
+        if (sizeof(void *) < 8) {
+          if (oldsdna->pointer_size == 8) {
+            BLI_endian_switch_int64_array((int64_t *)cur, old_name_array_len);
+          }
         }
       }
       else {