Better node splitting for large text insertions.

src/buffer.rs

@@ -156,13 +156,14 @@ impl TextNode {
         }
     }
 
-    /// Splits a leaf node into two roughly equal-sized children
+    /// Recursively splits a leaf node into roughly equal-sized children,
-    pub fn split(&mut self) {
+    /// being no larger than 'max_size'.
+    pub fn split(&mut self, max_size: uint) {
         if let TextNodeData::Branch(_, _) = self.data {
             panic!("TextNode::split(): attempt to split a non-leaf node.");
         }
         
-        if self.byte_count > 1 {
+        if self.byte_count > max_size {
             // Split data into two new text blocks
             let mut tn1 = box TextNode::new();
             let mut tn2 = box TextNode::new();
@@ -172,6 +173,9 @@ impl TextNode {
                 tn2 = box TextNode::new_from_str(tb.as_str().slice(pos, tb.len()));
             }
             
+            tn1.split(max_size);
+            tn2.split(max_size);
+            
             // Swap the old and new data
             let mut new_data = TextNodeData::Branch(tn1, tn2);
             mem::swap(&mut self.data, &mut new_data);
@@ -218,7 +222,7 @@ impl TextNode {
                 }
                 
                 if self.byte_count > MAX_LEAF_SIZE {
-                    self.split();
+                    self.split(MAX_LEAF_SIZE);
                 }
             },
             

src/main.rs

@@ -32,14 +32,17 @@ fn main() {
     
     let mut tb = TextBuffer::new();
 
-    for _ in range(0i, 1000) {
+    for _ in range(0i, 100) {
         tb.insert_text(args.arg_file.as_slice(), 0);
-        if tb.len() > 1024 {
-            tb.remove_text(27, 27+3);
-        }
     }
     
     tb.remove_text(3, 6);
+    tb.remove_text(8, 9);
+    tb.remove_text(40, 43);
+    
+    if tb.len() > 300 {
+        tb.remove_text(67, 285);
+    }
     
     println!("{}", tb);
 }