From d6192e94a8843d911bcbd8b20c385225e32eb496 Mon Sep 17 00:00:00 2001
From: Determinant <ted.sybil@gmail.com>
Date: Fri, 17 Nov 2017 12:04:04 -0500
Subject: adjust abstraction and mutability

---
 src/mapper.rs | 84 ++++++++++++++++++++++++++++++++---------------------------
 1 file changed, 46 insertions(+), 38 deletions(-)

(limited to 'src/mapper.rs')

diff --git a/src/mapper.rs b/src/mapper.rs
index 210b59f..fc02ed2 100644
--- a/src/mapper.rs
+++ b/src/mapper.rs
@@ -1,64 +1,72 @@
 #![allow(dead_code)]
+extern crate core;
 use memory::VMem;
 use cartridge::{Cartridge, BankType};
-use core::cell::UnsafeCell;
 
 pub struct Mapper2<'a> {
-    cart: &'a Cartridge,
-    prg_bank1: UnsafeCell<&'a [u8]>,
-    prg_bank2: UnsafeCell<&'a [u8]>,
-    chr_bank: UnsafeCell<&'a mut [u8]>,
-    sram: UnsafeCell<&'a mut [u8]>,
+    cart: Cartridge,
+    prg_bank1: &'a [u8],
+    prg_bank2: &'a [u8],
+    chr_bank: &'a mut [u8],
+    sram: &'a mut [u8],
     prg_nbank: usize
 }
 
 impl<'a> VMem for Mapper2<'a> {
     fn read(&self, addr: u16) -> u8 {
         let addr = addr as usize;
-        unsafe {
-            if addr < 0x2000 {         /* 0x2000 size bank */
-                (*self.chr_bank.get())[addr]
-            } else if addr >= 0xc000 { /* 0x4000 size bank */
-                (*self.prg_bank2.get())[addr - 0xc000]
-            } else if addr >= 0x8000 { /* 0x4000 size bank */
-                (*self.prg_bank1.get())[addr - 0x8000]
-            } else if addr >= 0x6000 {
-                (*self.sram.get())[addr - 0x6000]
-            } else {
-                panic!("unmapped address: 0x{:04x}", addr)
-            }
+        if addr < 0x2000 {         /* 0x2000 size bank */
+            self.chr_bank[addr]
+        } else if addr >= 0xc000 { /* 0x4000 size bank */
+            self.prg_bank2[addr - 0xc000]
+        } else if addr >= 0x8000 { /* 0x4000 size bank */
+            self.prg_bank1[addr - 0x8000]
+        } else if addr >= 0x6000 {
+            self.sram[addr - 0x6000]
+        } else {
+            panic!("unmapped address: 0x{:04x}", addr)
         }
     }
 
-    fn write(&self, addr: u16, data: u8) {
+    fn write(&mut self, addr: u16, data: u8) {
         let addr = addr as usize;
-        unsafe {
-            if addr < 0x2000 {
-                (*self.chr_bank.get())[addr] = data;
-            } else if addr >= 0x8000 {
-                (*self.prg_bank1.get()) =
-                    &*self.cart.get_bank(((data as usize) % self.prg_nbank) << 14,
-                    0x4000,
-                    BankType::PrgRom);
-            } else if addr >= 0x6000 {
-                (*self.sram.get())[addr - 0x6000] = data;
-            } else {
-                panic!("invalid write to address: 0x{:04x}", addr);
+        if addr < 0x2000 {
+            self.chr_bank[addr] = data;
+        } else if addr >= 0x8000 {
+            self.prg_bank1 = unsafe {
+                &*self.cart.get_bank(((data as usize) % self.prg_nbank) << 14,
+                0x4000,
+                BankType::PrgRom)
             }
+        } else if addr >= 0x6000 {
+            self.sram[addr - 0x6000] = data
+        } else {
+            panic!("invalid write to address: 0x{:04x}", addr);
         }
     }
 }
 
 impl<'a> Mapper2<'a> {
-    pub fn new(cart: &'a Cartridge) -> Self {
+    pub fn new(cart: Cartridge) -> Self {
         unsafe {
             let nbank = cart.get_size(BankType::PrgRom) >> 14;
-            Mapper2{cart,
-                prg_bank1: UnsafeCell::new(&*cart.get_bank(0, 0x4000, BankType::PrgRom)),
-                prg_bank2: UnsafeCell::new(&*cart.get_bank((nbank - 1) << 14, 0x4000, BankType::PrgRom)),
-                chr_bank: UnsafeCell::new(&mut *cart.get_bank(0, 0x2000, BankType::ChrRom)),
-                sram: UnsafeCell::new(&mut *cart.get_bank(0, 0x2000, BankType::Sram)),
-                prg_nbank: nbank}
+            let null = core::mem::uninitialized();
+            let mut m = Mapper2{cart,
+                        prg_nbank: nbank,
+                        prg_bank1: null,
+                        prg_bank2: null,
+                        chr_bank: core::mem::uninitialized(),
+                        sram: core::mem::uninitialized()};
+            {
+                let c = &mut m.cart;
+                    m.prg_bank1 = &*c.get_bank(0, 0x4000, BankType::PrgRom);
+                    m.prg_bank2 = &*c.get_bank((nbank - 1) << 14, 0x4000, BankType::PrgRom);
+                    m.chr_bank = &mut *c.get_bank(0, 0x2000, BankType::ChrRom);
+                    m.sram = &mut *c.get_bank(0, 0x2000, BankType::Sram);
+            }
+            m
         }
     }
+
+    pub fn get_cart(&self) -> &Cartridge {&self.cart}
 }
-- 
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