Add Memory trait for Rom, refactor instantiating

1 files changed, 33 insertions, 4 deletions

diff --git a/src/rom.rs b/src/rom.rs
index 77e6431..c054575 100644
--- a/src/rom.rs
+++ b/src/rom.rs
@@ -1,7 +1,8 @@
 use std::fmt;
+use crate::memory::Memory;
 
 pub struct Rom {
-    pub array: [u8; u16::max_value() as usize + 1],
+    array: [u8; u16::max_value() as usize + 1],
 }
 
 impl fmt::Debug for Rom {
@@ -83,8 +84,26 @@ impl HexLine {
 }
 
 impl Rom {
+    /// Empty constructor
+    pub fn new() -> Self {
+        Self { array: [0; u16::max_value() as usize + 1] }
+    }
+
+    /// Constructor from hex
     pub fn from_hex(hex: String) -> Result<Self, String> {
-        let mut array = [0; u16::max_value() as usize + 1];
+        Self::new().hex(hex)
+    }
+
+    /// Method for sequential consuming building
+    pub fn hex(mut self, hex: String) -> Result<Self, String> {
+        match self.load_hex(hex) {
+            Ok(_) => Ok(self),
+            Err(string) => Err(string),
+        }
+    }
+
+    /// Method for occasional incremental hex loading
+    pub fn load_hex(&mut self, hex: String) -> Result<(), String> {
         for (linenum, line) in hex.lines().enumerate() {
             let hex_line = match HexLine::from(line) {
                 Ok(value) => value,
@@ -94,12 +113,22 @@ impl Rom {
             match hex_line.rectyp {
                 Rectyp::Data => {
                     for (ptr, byte) in hex_line.data.iter().enumerate() {
-                        array[ptr + offset as usize] = *byte;
+                        self.array[ptr + offset as usize] = *byte;
                     }
                 }
                 Rectyp::EndOfFile => {}
             }
         }
-        Ok(Self { array })
+        Ok(())
+    }
+}
+
+impl Memory<u16> for Rom {
+    fn get(&self, a: u16) -> u8 {
+        self.array[a as usize]
+    }
+
+    fn set(&mut self, a: u16, v: u8) {
+        self.array[a as usize] = v;
     }
 }