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>

4 files changed, 22 insertions, 22 deletions

diff --git a/drivers/unix/dir_access_unix.cpp b/drivers/unix/dir_access_unix.cpp
index 22151b60c1..3323da5db4 100644
--- a/drivers/unix/dir_access_unix.cpp
+++ b/drivers/unix/dir_access_unix.cpp
@@ -406,7 +406,7 @@ Error DirAccessUnix::remove(String p_path) {
 	}
 }
 
-size_t DirAccessUnix::get_space_left() {
+uint64_t DirAccessUnix::get_space_left() {
 #ifndef NO_STATVFS
 	struct statvfs vfs;
 	if (statvfs(current_dir.utf8().get_data(), &vfs) != 0) {
diff --git a/drivers/unix/dir_access_unix.h b/drivers/unix/dir_access_unix.h
index 54f4a5c312..12994a6b76 100644
--- a/drivers/unix/dir_access_unix.h
+++ b/drivers/unix/dir_access_unix.h
@@ -79,7 +79,7 @@ public:
 	virtual Error rename(String p_path, String p_new_path);
 	virtual Error remove(String p_path);
 
-	virtual size_t get_space_left();
+	virtual uint64_t get_space_left();
 
 	virtual String get_filesystem_type() const;
 
diff --git a/drivers/unix/file_access_unix.cpp b/drivers/unix/file_access_unix.cpp
index 4c08380dd0..de9a7867ee 100644
--- a/drivers/unix/file_access_unix.cpp
+++ b/drivers/unix/file_access_unix.cpp
@@ -184,11 +184,11 @@ String FileAccessUnix::get_path_absolute() const {
 	return path;
 }
 
-void FileAccessUnix::seek(size_t p_position) {
+void FileAccessUnix::seek(uint64_t p_position) {
 	ERR_FAIL_COND_MSG(!f, "File must be opened before use.");
 
 	last_error = OK;
-	if (fseek(f, p_position, SEEK_SET)) {
+	if (fseeko(f, p_position, SEEK_SET)) {
 		check_errors();
 	}
 }
@@ -196,15 +196,15 @@ void FileAccessUnix::seek(size_t p_position) {
 void FileAccessUnix::seek_end(int64_t p_position) {
 	ERR_FAIL_COND_MSG(!f, "File must be opened before use.");
 
-	if (fseek(f, p_position, SEEK_END)) {
+	if (fseeko(f, p_position, SEEK_END)) {
 		check_errors();
 	}
 }
 
-size_t FileAccessUnix::get_position() const {
+uint64_t FileAccessUnix::get_position() const {
 	ERR_FAIL_COND_V_MSG(!f, 0, "File must be opened before use.");
 
-	long pos = ftell(f);
+	int64_t pos = ftello(f);
 	if (pos < 0) {
 		check_errors();
 		ERR_FAIL_V(0);
@@ -212,15 +212,15 @@ size_t FileAccessUnix::get_position() const {
 	return pos;
 }
 
-size_t FileAccessUnix::get_len() const {
+uint64_t FileAccessUnix::get_len() const {
 	ERR_FAIL_COND_V_MSG(!f, 0, "File must be opened before use.");
 
-	long pos = ftell(f);
+	int64_t pos = ftello(f);
 	ERR_FAIL_COND_V(pos < 0, 0);
-	ERR_FAIL_COND_V(fseek(f, 0, SEEK_END), 0);
-	long size = ftell(f);
+	ERR_FAIL_COND_V(fseeko(f, 0, SEEK_END), 0);
+	int64_t size = ftello(f);
 	ERR_FAIL_COND_V(size < 0, 0);
-	ERR_FAIL_COND_V(fseek(f, pos, SEEK_SET), 0);
+	ERR_FAIL_COND_V(fseeko(f, pos, SEEK_SET), 0);
 
 	return size;
 }
@@ -239,11 +239,11 @@ uint8_t FileAccessUnix::get_8() const {
 	return b;
 }
 
-int FileAccessUnix::get_buffer(uint8_t *p_dst, int p_length) const {
+uint64_t FileAccessUnix::get_buffer(uint8_t *p_dst, uint64_t p_length) const {
 	ERR_FAIL_COND_V(!p_dst && p_length > 0, -1);
-	ERR_FAIL_COND_V(p_length < 0, -1);
 	ERR_FAIL_COND_V_MSG(!f, -1, "File must be opened before use.");
-	int read = fread(p_dst, 1, p_length, f);
+
+	uint64_t read = fread(p_dst, 1, p_length, f);
 	check_errors();
 	return read;
 };
@@ -262,10 +262,10 @@ void FileAccessUnix::store_8(uint8_t p_dest) {
 	ERR_FAIL_COND(fwrite(&p_dest, 1, 1, f) != 1);
 }
 
-void FileAccessUnix::store_buffer(const uint8_t *p_src, int p_length) {
+void FileAccessUnix::store_buffer(const uint8_t *p_src, uint64_t p_length) {
 	ERR_FAIL_COND_MSG(!f, "File must be opened before use.");
 	ERR_FAIL_COND(!p_src);
-	ERR_FAIL_COND((int)fwrite(p_src, 1, p_length, f) != p_length);
+	ERR_FAIL_COND(fwrite(p_src, 1, p_length, f) != p_length);
 }
 
 bool FileAccessUnix::file_exists(const String &p_path) {
diff --git a/drivers/unix/file_access_unix.h b/drivers/unix/file_access_unix.h
index 998fad7909..6aa3e1529f 100644
--- a/drivers/unix/file_access_unix.h
+++ b/drivers/unix/file_access_unix.h
@@ -61,21 +61,21 @@ public:
 	virtual String get_path() const; /// returns the path for the current open file
 	virtual String get_path_absolute() const; /// returns the absolute path for the current open file
 
-	virtual void seek(size_t p_position); ///< seek to a given position
+	virtual void seek(uint64_t p_position); ///< seek to a given position
 	virtual void seek_end(int64_t p_position = 0); ///< seek from the end of file
-	virtual size_t get_position() const; ///< get position in the file
-	virtual size_t get_len() const; ///< get size of the file
+	virtual uint64_t get_position() const; ///< get position in the file
+	virtual uint64_t get_len() const; ///< get size of the file
 
 	virtual bool eof_reached() const; ///< reading passed EOF
 
 	virtual uint8_t get_8() const; ///< get a byte
-	virtual int get_buffer(uint8_t *p_dst, int p_length) const;
+	virtual uint64_t get_buffer(uint8_t *p_dst, uint64_t p_length) const;
 
 	virtual Error get_error() const; ///< get last error
 
 	virtual void flush();
 	virtual void store_8(uint8_t p_dest); ///< store a byte
-	virtual void store_buffer(const uint8_t *p_src, int p_length); ///< store an array of bytes
+	virtual void store_buffer(const uint8_t *p_src, uint64_t p_length); ///< store an array of bytes
 
 	virtual bool file_exists(const String &p_path); ///< return true if a file exists