1 files changed, 59 insertions, 0 deletions
diff --git a/meap/meap-code/ch3/ch3-file-states.rs b/meap/meap-code/ch3/ch3-file-states.rs
new file mode 100644
index 0000000..36510a5
--- /dev/null
+++ b/meap/meap-code/ch3/ch3-file-states.rs
@@ -0,0 +1,59 @@
+#[derive(Debug,PartialEq)]
+enum FileState {
+  Open,
+  Closed,
+}
+
+#[derive(Debug)]
+struct File {
+  name: String,
+  data: Vec<u8>,
+  state: FileState,
+}
+
+impl File {
+  fn new(name: &str) -> File {
+    File { name: String::from(name), data: Vec::new(), state: FileState::Closed }
+  }
+
+  fn read(self: &File, save_to: &mut Vec<u8>) -> Result<usize, String> {
+    if self.state != FileState::Open {
+      return Err(String::from("File must be open for reading"));
+    }
+    let mut tmp = self.data.clone();
+    let read_length = tmp.len();
+    save_to.reserve(read_length);
+    save_to.append(&mut tmp);
+    Ok(read_length)  // <6>
+  }
+}
+
+fn open(mut f: File) -> Result<File, String> {
+  f.state = FileState::Open;
+  Ok(f)
+}
+
+fn close(mut f: File) -> Result<File, String> {
+  f.state = FileState::Closed;
+  Ok(f)
+}
+
+fn main() {
+  let mut f5 = File::new("5.txt"); 
+
+  let mut buffer: Vec<u8> = vec![];
+
+  if f5.read(&mut buffer).is_err() {
+    println!("Error checking is working");
+  }
+
+  f5 = open(f5).unwrap();                        // <9>
+  let f5_length = f5.read(&mut buffer).unwrap(); // <9>
+  f5 = close(f5).unwrap();                       // <9>
+  
+  let text = String::from_utf8_lossy(&buffer);
+
+  println!("{:?}", f5);
+  println!("{} is {} bytes long", &f5.name, f5_length);
+  println!("{}", text);
+}
+\ No newline at end of file