1 files changed, 105 insertions, 0 deletions
diff --git a/src/rom.rs b/src/rom.rs
new file mode 100644
index 0000000..77e6431
--- /dev/null
+++ b/src/rom.rs
@@ -0,0 +1,105 @@
+use std::fmt;
+
+pub struct Rom {
+    pub array: [u8; u16::max_value() as usize + 1],
+}
+
+impl fmt::Debug for Rom {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let mut v: Vec<char> = vec![];
+        for (c, x) in self.array.iter().enumerate() {
+            for hex_char in format!("{:02X}", *x).chars() {
+                v.push(hex_char);
+            }
+            v.push(' ');
+            if c % 8 == 7 {
+                v.push('\n');
+            }
+        }
+        write!(f, "{}", v.iter().collect::<String>())
+    }
+}
+
+enum Rectyp {
+    Data,
+    EndOfFile,
+    //ExtendedSegAddr,
+    //StartSegAddr,
+    //ExtendedLinearAddr,
+    //StartLinearAddr,
+}
+
+struct HexLine {
+    rectyp: Rectyp,
+    offset: u16,
+    data: Vec<u8>,
+}
+
+impl HexLine {
+    fn from(s: &str) -> Result<Self, usize> {
+        // The shortest possible sequence is EOF (:00000001FF)
+        if s.len() < 11 {
+            return Err(usize::max_value());
+        }
+        if &s[0..1] != ":" {
+            return Err(0);
+        }
+        let offset = match u16::from_str_radix(&s[3..7], 16) {
+            Ok(value) => value,
+            Err(_) => return Err(3),
+        };
+        let bytecount = match usize::from_str_radix(&s[1..3], 16) {
+            Ok(value) => value,
+            Err(_) => return Err(1),
+        };
+
+        // If EOF reached
+        if &s[7..9] == "01" {
+            return Ok(HexLine {
+                rectyp: Rectyp::EndOfFile,
+                offset,
+                data: vec![0],
+            });
+        } else if &s[7..9] == "00" {
+            let mut counter = 9;
+            let mut data = vec![];
+            while counter < s.len() - 2 && counter < (9 + bytecount * 2) {
+                data.push(match u8::from_str_radix(&s[counter..counter + 2], 16) {
+                    Ok(value) => value,
+                    Err(_) => return Err(counter),
+                });
+                counter += 2;
+            }
+            // TODO: check checksum
+            return Ok(HexLine {
+                rectyp: Rectyp::Data,
+                offset,
+                data,
+            });
+        }
+
+        Err(3)
+    }
+}
+
+impl Rom {
+    pub fn from_hex(hex: String) -> Result<Self, String> {
+        let mut array = [0; u16::max_value() as usize + 1];
+        for (linenum, line) in hex.lines().enumerate() {
+            let hex_line = match HexLine::from(line) {
+                Ok(value) => value,
+                Err(charnum) => return Err(format!("ihex parsing error {}:{}", linenum, charnum)),
+            };
+            let offset = hex_line.offset;
+            match hex_line.rectyp {
+                Rectyp::Data => {
+                    for (ptr, byte) in hex_line.data.iter().enumerate() {
+                        array[ptr + offset as usize] = *byte;
+                    }
+                }
+                Rectyp::EndOfFile => {}
+            }
+        }
+        Ok(Self { array })
+    }
+}