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>

3 files changed, 11 insertions, 12 deletions

diff --git a/editor/editor_export.cpp b/editor/editor_export.cpp
index a368a9618e..b3755bef80 100644
--- a/editor/editor_export.cpp
+++ b/editor/editor_export.cpp
@@ -1222,12 +1222,12 @@ Error EditorExportPlatform::save_pack(const Ref<EditorExportPreset> &p_preset, c
 	}
 
 	for (int i = 0; i < pd.file_ofs.size(); i++) {
-		int string_len = pd.file_ofs[i].path_utf8.length();
-		int pad = _get_pad(4, string_len);
+		uint32_t string_len = pd.file_ofs[i].path_utf8.length();
+		uint32_t pad = _get_pad(4, string_len);
 
 		fhead->store_32(string_len + pad);
 		fhead->store_buffer((const uint8_t *)pd.file_ofs[i].path_utf8.get_data(), string_len);
-		for (int j = 0; j < pad; j++) {
+		for (uint32_t j = 0; j < pad; j++) {
 			fhead->store_8(0);
 		}
 
@@ -1269,8 +1269,8 @@ Error EditorExportPlatform::save_pack(const Ref<EditorExportPreset> &p_preset, c
 	uint8_t buf[bufsize];
 
 	while (true) {
-		int got = ftmp->get_buffer(buf, bufsize);
-		if (got <= 0) {
+		uint64_t got = ftmp->get_buffer(buf, bufsize);
+		if (got == 0) {
 			break;
 		}
 		f->store_buffer(buf, got);
@@ -1280,13 +1280,13 @@ Error EditorExportPlatform::save_pack(const Ref<EditorExportPreset> &p_preset, c
 
 	if (p_embed) {
 		// Ensure embedded data ends at a 64-bit multiple
-		int64_t embed_end = f->get_position() - embed_pos + 12;
-		int pad = embed_end % 8;
-		for (int i = 0; i < pad; i++) {
+		uint64_t embed_end = f->get_position() - embed_pos + 12;
+		uint64_t pad = embed_end % 8;
+		for (uint64_t i = 0; i < pad; i++) {
 			f->store_8(0);
 		}
 
-		int64_t pck_size = f->get_position() - pck_start_pos;
+		uint64_t pck_size = f->get_position() - pck_start_pos;
 		f->store_64(pck_size);
 		f->store_32(PACK_HEADER_MAGIC);
 
diff --git a/editor/fileserver/editor_file_server.cpp b/editor/fileserver/editor_file_server.cpp
index d80003a12a..b04e518b0b 100644
--- a/editor/fileserver/editor_file_server.cpp
+++ b/editor/fileserver/editor_file_server.cpp
@@ -230,8 +230,7 @@ void EditorFileServer::_subthread_start(void *s) {
 				cd->files[id]->seek(offset);
 				Vector<uint8_t> buf;
 				buf.resize(blocklen);
-				int read = cd->files[id]->get_buffer(buf.ptrw(), blocklen);
-				ERR_CONTINUE(read < 0);
+				uint32_t read = cd->files[id]->get_buffer(buf.ptrw(), blocklen);
 
 				print_verbose("GET BLOCK - offset: " + itos(offset) + ", blocklen: " + itos(blocklen));
 
diff --git a/editor/import/resource_importer_image.cpp b/editor/import/resource_importer_image.cpp
index 26c6a8462b..fa6ce5fc89 100644
--- a/editor/import/resource_importer_image.cpp
+++ b/editor/import/resource_importer_image.cpp
@@ -75,7 +75,7 @@ Error ResourceImporterImage::import(const String &p_source_file, const String &p
 
 	ERR_FAIL_COND_V_MSG(!f, ERR_CANT_OPEN, "Cannot open file from path '" + p_source_file + "'.");
 
-	size_t len = f->get_len();
+	uint64_t len = f->get_len();
 
 	Vector<uint8_t> data;
 	data.resize(len);