Beginnings of a text buffer.

src/buffer.rs

@@ -0,0 +1,53 @@
+use std::cmp::min;
+
+
+/// A block of text, contiguous in memory
+pub struct TextBlock {
+    pub data: Vec<u8>,
+}
+
+impl TextBlock {
+    pub fn new() -> TextBlock {
+        TextBlock {
+            data: Vec::<u8>::new()
+        }
+    }
+    
+    pub fn insert_text(&mut self, text: &str, pos: uint) {
+        let ins = min(pos, self.data.len());
+
+        // Grow data size		
+        self.data.grow(text.len(), 0);
+        
+        // Move old bytes forward
+        let mut from = self.data.len() - text.len();
+        let mut to = self.data.len();
+        while from > ins {
+            from -= 1;
+            to -= 1;
+            
+            self.data[to] = self.data[from];
+        }
+        
+        // Copy new bytes in
+        let mut i = ins;
+        for b in text.bytes() {
+            self.data[i] = b;
+            i += 1
+        }
+    }
+}
+
+
+// /// A rope text storage buffer, using TextBlocks for its underlying text
+// /// storage.
+// pub enum TextBuffer {
+//     Block(TextBlock),
+//     Node(Box<TextBuffer>, Box<TextBuffer>)
+// }
+// 
+// impl TextBuffer {
+//     pub fn new() -> TextBuffer {
+//         TextBuffer::Block(TextBlock::new())
+//     }
+// }

src/main.rs

@@ -3,6 +3,9 @@ extern crate docopt;
 extern crate serialize;
 
 use docopt::Docopt;
+use buffer::TextBlock; 
+
+mod buffer;
 
 
 // Usage documentation string
@@ -27,5 +30,13 @@ fn main() {
     // Get command-line arguments
     let args: Args = Docopt::new(USAGE).and_then(|d| d.decode()).unwrap_or_else(|e| e.exit());
     
-    println!("Hello! {}", args.arg_file);
+    let mut tb = TextBlock::new();
+
+    for _ in range(0i, 50) {
+        tb.insert_text("Hello", 0);
+        tb.insert_text("Goodbye", 0);
+        tb.insert_text(args.arg_file.as_slice(), 0);
+    }
+    
+    println!("{}", std::str::from_utf8(tb.data.as_slice()).unwrap());
 }