Massive save state speedup

rustual-boy-libretro/src/lib.rs

@@ -60,6 +60,7 @@ pub struct Context {
     system: Option<System>,
     video_output_frame_buffer: OutputBuffer,
     audio_frame_buffer: Vec<AudioFrame>,
+    last_serialized_state: Option<Vec<u8>>,
 }
 
 impl Context {
@@ -68,10 +69,12 @@ impl Context {
             system: None,
             video_output_frame_buffer: OutputBuffer::Xrgb1555(vec![0; DISPLAY_PIXELS as usize]),
             audio_frame_buffer: vec![(0, 0); (SAMPLE_RATE as usize) / 50 * 2], // double space needed for 1 frame for lots of skid room
+            last_serialized_state: None,
         }
     }
 
     fn load_game(&mut self, game_info: &GameInfo) -> bool {
+        self.last_serialized_state = None;
         unsafe {
             // It seems retroarch (and possibly other frontends) is a bit finicky with accepting the set pixel format
             //  callback, so we should call it a few times before giving up. We don't want to loop forever here though,
@@ -110,6 +113,7 @@ impl Context {
     }
 
     fn unload_game(&mut self) {
+        self.last_serialized_state = None;
         self.system = None;
     }
 
@@ -132,12 +136,14 @@ impl Context {
     }
 
     fn reset(&mut self) {
+        self.last_serialized_state = None;
         // Pull out rom/sram from existing system, and build new system around them
         let (rom, sram) = self.system.as_ref().map(|system| (system.virtual_boy.interconnect.rom.clone(), system.virtual_boy.interconnect.sram.clone())).unwrap();
         self.system = Some(System::new(rom, sram));
     }
 
     fn run_frame(&mut self) {
+        self.last_serialized_state = None;
         unsafe {
             CALLBACKS.input_poll();
 
@@ -219,11 +225,19 @@ impl Context {
         }
     }
 
-    fn get_serialized_size(&self) -> size_t {
+    fn get_serialized_size(&mut self) -> size_t {
+        if let Some(ref serialized_bytes) = self.last_serialized_state {
+            return serialized_bytes.len();
+        }
+
         if let Some(ref system) = self.system {
             let state = get_state(&system.virtual_boy);
             match serialize(state) {
-                Ok(serialized_bytes) => serialized_bytes.len() as _,
+                Ok(serialized_bytes) => {
+                    let len = serialized_bytes.len();
+                    self.last_serialized_state = Some(serialized_bytes);
+                    len
+                }
                 Err(err) => {
                     // TODO: Remove this..?
                     println!("****** RUH ROH: Serialization failed for some reason :((( {}", err);
@@ -236,13 +250,21 @@ impl Context {
         }
     }
 
-    fn serialize(&self, data: *mut c_void, size: size_t) -> bool {
+    fn serialize(&mut self, data: *mut c_void, size: size_t) -> bool {
+        if let Some(ref serialized_bytes) = self.last_serialized_state {
+            let result = serialized_bytes.len() <= size;
+            if result {
+                unsafe { ptr::copy_nonoverlapping(serialized_bytes.as_ptr(), data as *mut u8, serialized_bytes.len()) };
+            }
+            return result;
+        }
         if let Some(ref system) = self.system {
             let state = get_state(&system.virtual_boy);
             match serialize(state) {
                 Ok(serialized_bytes) => {
-                    if serialized_bytes.len() == size {
-                        unsafe { ptr::copy_nonoverlapping(serialized_bytes.as_ptr(), data as *mut u8, size) };
+                    if serialized_bytes.len() <= size {
+                        unsafe { ptr::copy_nonoverlapping(serialized_bytes.as_ptr(), data as *mut u8, serialized_bytes.len()) };
+                        self.last_serialized_state = Some(serialized_bytes);
 
                         true
                     } else {
@@ -262,6 +284,7 @@ impl Context {
     }
 
     fn unserialize(&mut self, data: *const c_void, size: size_t) -> bool {
+        self.last_serialized_state = None;
         let data_slice = unsafe { slice::from_raw_parts(data as *const u8, size) };
         match deserialize(data_slice) {
             Ok(deserialized_state) => {

rustual-boy-serialization/Cargo.toml

@@ -7,5 +7,6 @@ authors = ["ferris <yupferris@gmail.com>"]
 rustual-boy-core = { path="../rustual-boy-core" }
 serde = "1.0"
 serde_derive = "1.0"
+serde_bytes="0.10"
 bincode = "1.0"
 lz4 = "*"

rustual-boy-serialization/src/lib.rs

@@ -4,16 +4,16 @@ extern crate rustual_boy_core;
 extern crate serde_derive;
 
 extern crate serde;
+extern crate serde_bytes;
 extern crate bincode;
 
 extern crate lz4;
 
 pub mod version1;
+mod serde_ibytes;
 
 use lz4::{EncoderBuilder, Decoder};
 
-use std::io::{copy, Cursor};
-
 use rustual_boy_core::rom::*;
 use rustual_boy_core::timer::*;
 use rustual_boy_core::vip::*;
@@ -36,11 +36,13 @@ pub enum ApplyError {
 
 pub fn serialize(state: State) -> Result<Vec<u8>, String> {
     let versioned_state = VersionedState::Version1(state);
-    let bincode = bincode::serialize(&versioned_state).map_err(|e| format!("Couldn't serialize bincode: {}", e))?;
-    let mut cursor = Cursor::new(bincode);
-    let encoded = Vec::new();
-    let mut encoder = EncoderBuilder::new().build(encoded).map_err(|e| format!("Couldn't build lz4 encoder: {}", e))?;
-    copy(&mut cursor, &mut encoder).map_err(|e| format!("Couldn't encode lz4: {}", e))?;
+    let encoded = Vec::with_capacity(512 * 1024);
+    let mut encoder = EncoderBuilder::new()
+        .level(2)
+        .block_size(lz4::BlockSize::Max1MB)
+        .build(encoded)
+        .map_err(|e| format!("Couldn't build lz4 encoder: {}", e))?;
+    bincode::serialize_into(&mut encoder, &versioned_state).map_err(|e| format!("Couldn't save state: {}", e))?;
     let (encoded, result) = encoder.finish();
     if let Err(e) = result {
         return Err(format!("Couldn't finish lz4 encoding: {}", e));
@@ -49,10 +51,8 @@ pub fn serialize(state: State) -> Result<Vec<u8>, String> {
 }
 
 pub fn deserialize(encoded: &[u8]) -> Result<State, String> {
-    let mut decoder = Decoder::new(encoded).map_err(|e| format!("Couldn't build lz4 decoder: {}", e))?;
-    let mut bincode = Vec::new();
-    copy(&mut decoder, &mut bincode).map_err(|e| format!("Couldn't decode lz4: {}", e))?;
-    let versioned_state = bincode::deserialize(&bincode).map_err(|e| format!("Couldn't deserialize bincode: {}", e))?;
+    let decoder = Decoder::new(encoded).map_err(|e| format!("Couldn't build lz4 decoder: {}", e))?;
+    let versioned_state = bincode::deserialize_from(decoder).map_err(|e| format!("Couldn't deserialize state: {}", e))?;
     Ok(match versioned_state {
         VersionedState::Version1(state) => state,
     })

rustual-boy-serialization/src/serde_ibytes.rs

@@ -0,0 +1,31 @@
+use std::{mem, slice};
+use serde_bytes::ByteBuf;
+use serde::{Serializer, Deserializer, Deserialize};
+
+pub fn deserialize<'de, T, D>(deserializer: D) -> Result<T, D::Error>
+    where T: From<Vec<i8>>,
+          D: Deserializer<'de>
+{
+    ByteBuf::deserialize(deserializer).map(|buf| {
+        let mut u8_v: Vec<u8> = buf.into();
+
+        let i8_v = unsafe {
+            Vec::from_raw_parts(
+                u8_v.as_mut_ptr() as *mut i8,
+                u8_v.len(),
+                u8_v.capacity()
+            )
+        };
+        mem::forget(u8_v);
+        i8_v.into()
+    })
+}
+
+pub fn serialize<T, S>(bytes: &T, serializer: S) -> Result<S::Ok, S::Error>
+    where T: ?Sized + AsRef<[i8]>,
+          S: Serializer
+{
+    let i8_s: &[i8] = bytes.as_ref();
+    let u8_s: &[u8] = unsafe { slice::from_raw_parts(i8_s.as_ptr() as *const u8, i8_s.len()) };
+    serializer.serialize_bytes(u8_s)
+}

rustual-boy-serialization/src/version1.rs

@@ -1,4 +1,6 @@
 use std::collections::HashSet;
+use serde_bytes;
+use serde_ibytes;
 
 #[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
 pub struct State {
@@ -8,7 +10,9 @@ pub struct State {
 
 #[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
 pub struct InterconnectState {
+    #[serde(with = "serde_bytes")]
     pub rom: Box<[u8]>,
+    #[serde(with = "serde_bytes")]
     pub wram: Box<[u8]>,
     pub sram: SramState,
     pub vip: VipState,
@@ -48,6 +52,7 @@ pub struct GamePadState {
 
 #[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
 pub struct SramState {
+    #[serde(with = "serde_bytes")]
     pub bytes: Box<[u8]>,
 
     pub size: usize,
@@ -88,6 +93,7 @@ pub enum DrawingStateState {
 
 #[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
 pub struct VipState {
+    #[serde(with = "serde_bytes")]
     pub vram: Box<[u8]>,
 
     pub display_state: DisplayStateState,
@@ -250,7 +256,9 @@ pub struct NoiseSoundState {
 
 #[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
 pub struct VsuState {
+    #[serde(with = "serde_bytes")]
     pub waveform_data: Box<[u8]>,
+    #[serde(with = "serde_ibytes")]
     pub mod_data: Box<[i8]>,
 
     pub sound1: StandardSoundState,