Basic rewind works!

Makefile.win32

@@ -1,6 +1,6 @@
 TARGET = ssnes.exe
 JTARGET = ssnes-joyconfig.exe
-OBJ = ssnes.o file.o driver.o conf/config_file.o settings.o dynamic.o message.o
+OBJ = ssnes.o file.o driver.o conf/config_file.o settings.o dynamic.o message.o rewind.o
 JOBJ = conf/config_file.o tools/main-stub.o tools/ssnes-joyconfig.o
 
 CC = gcc

config.def.h

@@ -184,6 +184,7 @@ static const struct snes_keybind snes_keybinds_1[] = {
    { SSNES_STATE_SLOT_PLUS,            SDLK_F7,     NO_BTN,      AXIS_NONE },
    { SSNES_AUDIO_INPUT_RATE_PLUS,      SDLK_KP_PLUS, NO_BTN,     AXIS_NONE },
    { SSNES_AUDIO_INPUT_RATE_MINUS,     SDLK_KP_MINUS, NO_BTN,    AXIS_NONE },
+   { SSNES_REWIND,                     SDLK_r,      NO_BTN,      AXIS_NONE },
    { -1 }
 };
 

driver.h

@@ -36,6 +36,7 @@ enum
    SSNES_STATE_SLOT_MINUS,
    SSNES_AUDIO_INPUT_RATE_PLUS,
    SSNES_AUDIO_INPUT_RATE_MINUS,
+   SSNES_REWIND,
 };
 
 struct snes_keybind

general.h

@@ -24,6 +24,7 @@
 #include <stdio.h>
 #include "record/ffemu.h"
 #include "message.h"
+#include "rewind.h"
 
 #ifdef HAVE_CONFIG_H
 #include "config.h"
@@ -35,7 +36,7 @@
 
 
 #define MAX_PLAYERS 5
-#define MAX_BINDS 22 // Needs to be increased every time there are new binds added.
+#define MAX_BINDS 23 // Needs to be increased every time there are new binds added.
 #define SSNES_NO_JOYPAD 0xFFFF
 struct settings
 {
@@ -145,6 +146,10 @@ struct global
 
    msg_queue_t *msg_queue;
 
+   state_manager_t *state_manager;
+   void *state_buf;
+   bool rewind_enable;
+
 #ifdef HAVE_FFMPEG
    ffemu_t *rec;
    char record_path[256];

rewind.c

@@ -21,6 +21,8 @@
 #include <stdbool.h>
 #include <string.h>
 
+//#include <stdio.h>
+
 struct state_manager
 {
    uint64_t *buffer;
@@ -120,6 +122,7 @@ static void reassign_bottom(state_manager_t *state)
 
 static void generate_delta(state_manager_t *state, const void *data, bool aligned)
 {
+   unsigned patch_size = 0;
    bool crossed = false;
    const uint32_t *old_state = state->tmp_state;
    uint32_t *new_state = aligned ? (uint32_t*)data : state->scratch_buf;
@@ -138,6 +141,7 @@ static void generate_delta(state_manager_t *state, const void *data, bool aligne
       // This, if states don't really differ much, we'll save lots of space :) Hopefully this will work really well with save states.
       if (xor)
       {
+         patch_size++;
          state->buffer[state->top_ptr] = (i << 32) | xor;
          state->top_ptr = (state->top_ptr + 1) % state->buf_size;
 
@@ -148,6 +152,8 @@ static void generate_delta(state_manager_t *state, const void *data, bool aligne
 
    if (crossed)
       reassign_bottom(state);
+
+   //fprintf(stderr, "DELTA SIZE: %u, ORIG SIZE: %u\n", (unsigned)patch_size << 3, (unsigned)state->state_size << 2);
 }
 
 bool state_manager_push(state_manager_t *state, const void *data, bool aligned)

ssnes.c

@@ -28,6 +28,7 @@
 #include "general.h"
 #include "dynamic.h"
 #include "record/ffemu.h"
+#include "rewind.h"
 #include <assert.h>
 #ifdef HAVE_SRC
 #include <samplerate.h>
@@ -636,6 +637,22 @@ static void deinit_msg_queue(void)
       msg_queue_free(g_extern.msg_queue);
 }
 
+static void init_rewind(void)
+{
+   size_t serial_size = snes_serialize_size();
+   g_extern.state_buf = malloc(serial_size);
+   snes_serialize(g_extern.state_buf, serial_size);
+   g_extern.state_manager = state_manager_new(serial_size, 10 << 20, g_extern.state_buf);
+}
+
+static void deinit_rewind(void)
+{
+   if (g_extern.state_manager)
+      state_manager_free(g_extern.state_manager);
+   if (g_extern.state_buf)
+      free(g_extern.state_buf);
+}
+
 static void fill_pathnames(void)
 {
    switch (g_extern.game_type)
@@ -773,6 +790,24 @@ static void check_input_rate(void)
    }
 }
 
+static void check_rewind(void)
+{
+   if (!g_extern.state_manager)
+      return;
+
+   if (driver.input->key_pressed(driver.input_data, SSNES_REWIND))
+   {
+      void *buf;
+      if (state_manager_pop(g_extern.state_manager, &buf))
+         snes_unserialize(buf, snes_serialize_size());
+   }
+   else
+   {
+      snes_serialize(g_extern.state_buf, snes_serialize_size());
+      state_manager_push(g_extern.state_manager, g_extern.state_buf, true);
+   }
+}
+
 static void do_state_checks(void)
 {
    set_fast_forward_button(driver.input->key_pressed(driver.input_data, SSNES_FAST_FORWARD_KEY));
@@ -781,6 +816,7 @@ static void do_state_checks(void)
    check_savestates();
    check_fullscreen();
    check_input_rate();
+   check_rewind();
 }
 
 
@@ -817,6 +853,7 @@ int main(int argc, char *argv[])
 #endif
 
    init_msg_queue();
+   init_rewind();
 
    // Main loop
    for(;;)
@@ -833,6 +870,7 @@ int main(int argc, char *argv[])
       psnes_run();
    }
 
+   deinit_rewind();
    deinit_msg_queue();
 #ifdef HAVE_FFMPEG
    deinit_recording();