Make all file access 64-bit (uint64_t)

This changes the types of a big number of variables.

General rules:
- Using `uint64_t` in general. We also considered `int64_t` but eventually
  settled on keeping it unsigned, which is also closer to what one would expect
  with `size_t`/`off_t`.
- We only keep `int64_t` for `seek_end` (takes a negative offset from the end)
  and for the `Variant` bindings, since `Variant::INT` is `int64_t`. This means
  we only need to guard against passing negative values in `core_bind.cpp`.
- Using `uint32_t` integers for concepts not needing such a huge range, like
  pages, blocks, etc.

In addition:
- Improve usage of integer types in some related places; namely, `DirAccess`,
  core binds.

Note:
- On Windows, `_ftelli64` reports invalid values when using 32-bit MinGW with
  version < 8.0. This was an upstream bug fixed in 8.0. It breaks support for
  big files on 32-bit Windows builds made with that toolchain. We might add a
  workaround.

Fixes #44363.
Fixes godotengine/godot-proposals#400.

Co-authored-by: Rémi Verschelde <rverschelde@gmail.com>

2 files changed, 2 insertions, 2 deletions

diff --git a/platform/osx/display_server_osx.mm b/platform/osx/display_server_osx.mm
index 473ae95036..0a232357b5 100644
--- a/platform/osx/display_server_osx.mm
+++ b/platform/osx/display_server_osx.mm
@@ -3467,7 +3467,7 @@ void DisplayServerOSX::set_native_icon(const String &p_filename) {
 	ERR_FAIL_COND(!f);
 
 	Vector<uint8_t> data;
-	uint32_t len = f->get_len();
+	uint64_t len = f->get_len();
 	data.resize(len);
 	f->get_buffer((uint8_t *)&data.write[0], len);
 	memdelete(f);
diff --git a/platform/osx/export/export.cpp b/platform/osx/export/export.cpp
index 51204bc8f6..a7868efaa8 100644
--- a/platform/osx/export/export.cpp
+++ b/platform/osx/export/export.cpp
@@ -312,7 +312,7 @@ void EditorExportPlatformOSX::_make_icon(const Ref<Image> &p_icon, Vector<uint8_
 			}
 
 			int ofs = data.size();
-			uint32_t len = f->get_len();
+			uint64_t len = f->get_len();
 			data.resize(data.size() + len + 8);
 			f->get_buffer(&data.write[ofs + 8], len);
 			memdelete(f);