Read basics of INES/NES2.0 files to a cart file

src/cart.rs

@@ -1,37 +1,87 @@
+use std::iter::repeat;
+
 use mem::Mem;
 
-pub struct Cart;
+pub struct Cart
+{
+    prg_rom_pages: Vec<PrgRom>,
+    prg_ram_pages: Vec<PrgRam>,
+    chr_rom_pages: Vec<ChrMem>,
+    chr_ram_pages: Vec<ChrMem>,
+    sram_pages: Vec<Sram>,
+}
 
-struct PrgMem
+impl Cart
+{
+    pub fn new(num_prg_ram: usize, num_chr_ram: usize, num_sram: usize) -> Cart
+    {
+        let mut cart = Cart{
+            prg_rom_pages: Vec::new(),
+            chr_rom_pages: Vec::new(),
+            prg_ram_pages: Vec::new(),
+            chr_ram_pages: Vec::new(),
+            sram_pages:    Vec::new(),
+        };
+        for _ in 0..num_prg_ram { cart.prg_ram_pages.push(PrgRam::new()); }
+        for _ in 0..num_chr_ram { cart.chr_ram_pages.push(ChrMem::new_ram()); }
+        for _ in 0..num_sram { cart.sram_pages.push(Sram::new()); }
+        return cart;
+    }
+
+    pub fn load_prg_rom(&mut self, prg_rom: &[u8; 0x4000]) 
+    {
+        self.prg_rom_pages.push(PrgRom::new(*prg_rom));
+    }
+    pub fn load_chr_rom(&mut self, chr_rom: &[u8; 0x2000])
+    {
+        self.chr_rom_pages.push(ChrMem::new_rom(*chr_rom));
+    }
+}
+
+struct PrgRom
 {
-    ram: bool,
     mem: [u8; 0x4000],
 }
 
-impl PrgMem
+impl PrgRom
 {
-    fn new(ram: bool) -> PrgMem
+    fn new(data: [u8; 0x4000]) -> PrgRom
     {
-        PrgMem{ram: ram, mem: [0; 0x4000]}
+        PrgRom{mem: data}
     }
 }
 
-impl Mem<u16, u8> for PrgMem
+impl Mem<u16, u8> for PrgRom
 {
     fn read_word(&self, addr: u16) -> u8
     {
         self.mem[(addr%0x4000) as usize]
     }
+    fn write_word(&mut self, _: u16, _: u8)
+    {
+        panic!("Unable to write to PrgRom");
+    }
+}
+
+struct PrgRam
+{
+    mem: [u8; 0x2000],
+}
+
+impl PrgRam
+{
+    fn new() -> PrgRam { PrgRam{mem: [0; 0x2000]} }
+}
+
+impl Mem<u16, u8> for PrgRam
+{
+    fn read_word(&self, addr: u16) -> u8
+    {
+        self.mem[(addr%0x2000) as usize]
+    }
     fn write_word(&mut self, addr: u16, word: u8)
     {
-        if self.ram
-        {
-            self.mem[(addr%0x4000) as usize] = word
-        }
-        else
-        {
-            panic!("Unable to write to PrgRom");
-        }
+        self.mem[(addr%0x2000) as usize] = word
     }
 }
 
@@ -43,10 +93,8 @@ struct ChrMem
 
 impl ChrMem
 {
-    fn new(ram: bool) -> ChrMem
-    {
-        ChrMem{ram: ram, mem: [0; 0x2000]}
-    }
+    fn new_rom(data: [u8; 0x2000]) -> ChrMem { ChrMem{ram: false, mem: data} }
+    fn new_ram() -> ChrMem { ChrMem{ram: true, mem: [0; 0x2000]} }
 }
 
 impl Mem<u16, u8> for ChrMem
@@ -70,18 +118,23 @@ impl Mem<u16, u8> for ChrMem
 
 struct Sram
 {
-    ram: [u8; 0x2000],
+    mem: [u8; 0x2000],
+}
+
+impl Sram
+{
+    fn new() -> Sram { Sram{mem: [0; 0x2000]} }
 }
 
 impl Mem<u16, u8> for Sram
 {
     fn read_word(&self, addr: u16) -> u8
     {
-        self.ram[(addr%0x2000) as usize]
+        self.mem[(addr%0x2000) as usize]
     }
     fn write_word(&mut self, addr: u16, word: u8)
     {
-        self.ram[(addr%0x2000) as usize] = word
+        self.mem[(addr%0x2000) as usize] = word
     }
 }
 

src/parser/nes_2.rs

@@ -18,7 +18,32 @@ impl NesParser for Parser
         let mut header_bytes: [u8; 15] = [0; 15];
         let _ = file.read_exact(&mut header_bytes);
         let header = Nes2Header::new(header_bytes);
-        return Cart;
+        let mut cart = 
+            if header.nes_2_rules 
+            {
+                Cart::new((header.prgram_bat_backed + header.prgram_not_bat_backed) as usize,
+                          (header.chrram_bat_backed + header.chrram_not_bat_backed) as usize,
+                          0)
+            }
+            else
+            {
+                Cart::new(header.prg_ram_pages as usize, 0, 0)
+            };
+        // Read 16384 byte PrgRom blocks
+        for _ in 0..header.prg_pages
+        {
+            let mut buf: [u8; 0x4000] = [0; 0x4000];
+            let _ = file.read_exact(&mut buf);
+            cart.load_prg_rom(&buf);
+        }
+        // Read 8192 byte ChrRom blocks
+        for _ in 0..header.chr_pages
+        {
+            let mut buf: [u8; 0x2000] = [0; 0x2000];
+            let _ = file.read_exact(&mut buf);
+            cart.load_chr_rom(&buf);
+        }
+        return cart;
     }
 }