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, 3 insertions, 3 deletions

diff --git a/platform/javascript/api/javascript_tools_editor_plugin.cpp b/platform/javascript/api/javascript_tools_editor_plugin.cpp
index 7a2c2b2335..015440f5be 100644
--- a/platform/javascript/api/javascript_tools_editor_plugin.cpp
+++ b/platform/javascript/api/javascript_tools_editor_plugin.cpp
@@ -79,7 +79,7 @@ void JavaScriptToolsEditorPlugin::_zip_file(String p_path, String p_base_path, z
 		return;
 	}
 	Vector<uint8_t> data;
-	int len = f->get_len();
+	uint64_t len = f->get_len();
 	data.resize(len);
 	f->get_buffer(data.ptrw(), len);
 	f->close();
diff --git a/platform/javascript/export/export.cpp b/platform/javascript/export/export.cpp
index 951d86d09e..e398072312 100644
--- a/platform/javascript/export/export.cpp
+++ b/platform/javascript/export/export.cpp
@@ -170,8 +170,8 @@ public:
 
 		while (true) {
 			uint8_t bytes[4096];
-			int read = f->get_buffer(bytes, 4096);
-			if (read < 1) {
+			uint64_t read = f->get_buffer(bytes, 4096);
+			if (read == 0) {
 				break;
 			}
 			err = peer->put_data(bytes, read);