implement cart save write

README.md

@@ -100,7 +100,7 @@ If you want leave all parameters in default values, you can specify an empty opt
 
 These parameters behave the same as those in the `fs:USER` 3DS service functions: `FormatSaveData`, `CreateSystemSaveData` and `CreateExtSaveData`. However, the `max_dir`/`max_file` specified here is two/one larger than the one in `CreateExtSaveData`, as the latter one automatically counts the required `/user`, `/boss` and `/icon`.
 
-Title database files currently doesn't support `--format`.
+Title database files and cartridge save currently don't support `--format`.
 
 ## Example command
 ```bash

libsave3ds/src/cart_save_data.rs

@@ -0,0 +1,58 @@
+use crate::aes_ctr_file::*;
+use crate::error::*;
+use crate::file_system::*;
+use crate::random_access_file::*;
+use crate::save_data::*;
+use crate::wear_leveling::*;
+use std::rc::Rc;
+
+pub struct CartSaveData {
+    wear_leveling: Rc<WearLeveling>,
+    save_data: SaveData,
+}
+
+impl CartSaveData {
+    pub fn new(
+        file: Rc<dyn RandomAccessFile>,
+        key: [u8; 16],
+        key_cmac: [u8; 16],
+        repeat_ctr: bool,
+    ) -> Result<CartSaveData, Error> {
+        let wear_leveling = Rc::new(WearLeveling::new(file)?);
+
+        let save = Rc::new(AesCtrFile::new(
+            wear_leveling.clone(),
+            key,
+            [0; 16],
+            repeat_ctr,
+        ));
+
+        Ok(CartSaveData {
+            wear_leveling,
+            save_data: SaveData::new(save, SaveDataType::Cart(key_cmac))?,
+        })
+    }
+}
+
+impl FileSystem for CartSaveData {
+    type FileType = <SaveData as FileSystem>::FileType;
+    type DirType = <SaveData as FileSystem>::DirType;
+    type NameType = <SaveData as FileSystem>::NameType;
+
+    fn open_file(&self, ino: u32) -> Result<Self::FileType, Error> {
+        self.save_data.open_file(ino)
+    }
+
+    fn open_dir(&self, ino: u32) -> Result<Self::DirType, Error> {
+        self.save_data.open_dir(ino)
+    }
+
+    fn commit(&self) -> Result<(), Error> {
+        self.save_data.commit()?;
+        self.wear_leveling.commit()
+    }
+
+    fn stat(&self) -> Result<Stat, Error> {
+        self.save_data.stat()
+    }
+}

libsave3ds/src/lib.rs

@@ -1,5 +1,6 @@
 mod aes_ctr_file;
 mod byte_struct_common;
+mod cart_save_data;
 pub mod db;
 mod diff;
 mod difi_partition;
@@ -29,6 +30,7 @@ mod wear_leveling;
 use aes::block_cipher_trait::generic_array::GenericArray;
 use aes::block_cipher_trait::*;
 use aes::*;
+use cart_save_data::*;
 use db::*;
 use disk_file::DiskFile;
 use error::*;
@@ -553,28 +555,19 @@ impl Resource {
         Ok((key_y, repeat_ctr))
     }
 
-    pub fn open_cart_save(&self, path: &str, write: bool) -> Result<SaveData, Error> {
+    pub fn open_cart_save(&self, path: &str, write: bool) -> Result<CartSaveData, Error> {
         let file = Rc::new(DiskFile::new(
             std::fs::OpenOptions::new()
                 .read(true)
                 .write(write)
                 .open(path)?,
         )?);
 
-        let save = wear_leveling::WearLeveling::new(file)?;
-
         let (key_y, repeat_ctr) = self.get_cart_save_key_y()?;
         let key = key_engine::scramble(self.key_x_dec.ok_or(Error::MissingBoot9)?, key_y);
         let key_cmac = key_engine::scramble(self.key_x_sign.ok_or(Error::MissingBoot9)?, key_y);
 
-        let save = Rc::new(aes_ctr_file::AesCtrFile::new(
-            Rc::new(save),
-            key,
-            [0; 16],
-            repeat_ctr,
-        ));
-
-        SaveData::new(save, SaveDataType::Cart(key_cmac))
+        CartSaveData::new(file, key, key_cmac, repeat_ctr)
     }
 
     pub fn open_db(&self, db_type: DbType, write: bool) -> Result<Db, Error> {

libsave3ds/src/memory_file.rs

@@ -12,6 +12,14 @@ impl MemoryFile {
             data: RefCell::new(data),
         }
     }
+
+    pub fn from_file(file: &dyn RandomAccessFile) -> Result<MemoryFile, Error> {
+        let mut data = vec![0; file.len()];
+        file.read(0, &mut data)?;
+        Ok(MemoryFile {
+            data: RefCell::new(data),
+        })
+    }
 }
 
 impl RandomAccessFile for MemoryFile {

libsave3ds/src/save_data.rs

@@ -341,8 +341,10 @@ impl SaveData {
                 file_table,
                 param.max_file + 1,
             )?;
-            let dir_table_combo = OffsetOrFatFile::from_offset(info.dir_table_offset.unwrap() as u64);
-            let file_table_combo = OffsetOrFatFile::from_offset(info.file_table_offset.unwrap() as u64);
+            let dir_table_combo =
+                OffsetOrFatFile::from_offset(info.dir_table_offset.unwrap() as u64);
+            let file_table_combo =
+                OffsetOrFatFile::from_offset(info.file_table_offset.unwrap() as u64);
             (dir_table_combo, file_table_combo)
         } else {
             let fat = Fat::new(fat_table, data, info.block_len)?;