1 files changed, 115 insertions, 11 deletions
diff --git a/src/tree.rs b/src/tree.rs
index d3cca22..c7e8aae 100644
--- a/src/tree.rs
+++ b/src/tree.rs
@@ -1,22 +1,126 @@
-use super::symbols::Symbols;
+use std::collections::{BinaryHeap, HashMap};
 
-struct Node {
-    occurence: usize,
+use super::bits::BitSet;
+
+pub struct Node {
+    occurences: usize,
     content: Content,
 }
 
+impl Node {
+    fn join(left: Node, right: Node) -> Node {
+        Node {
+            occurences: left.occurences + right.occurences,
+            content: Content::Parent {
+                left:  Box::new(left),
+                right: Box::new(right),
+            }
+        }
+    }
+}
+
 enum Content {
-    Leaf(i8),
+    Leaf(u8),
     Parent {
-        left: Box<Node>,
+        left:  Box<Node>,
         right: Box<Node>,
     },
 }
 
-type Tree = Node;
+pub type Tree = Node;
+
+impl Tree {
+    pub fn from_data(data: &[u8]) -> Tree {
+        let mut counter: HashMap<u8, usize> = HashMap::new();
+        for k in data {
+            let v = match counter.get(&k) {
+                Some(count) => count + 1,
+                None        => 1,
+            };
+            counter.insert(*k, v);
+        }
+        let mut heap: BinaryHeap<Node> = counter
+            .iter()
+            .map(|(k, v)| Node { occurences: *v, content: Content::Leaf(*k) })
+            .collect();
+        while heap.len() >= 2 {
+            let first = heap.pop().unwrap();
+            let second = heap.pop().unwrap();
+            let n = Node::join(first, second);
+            heap.push(n);
+        }
+        heap.pop().unwrap()
+    }
+
+    pub fn to_bit_map(&self) -> HashMap<u8, BitSet> {
+        match &self.content {
+            Content::Leaf(b) => {
+                let mut hm = HashMap::with_capacity(1);
+                hm.insert(*b, BitSet::new());
+                hm
+            },
+            Content::Parent { left, right } => {
+                let mut left_hm = left.to_bit_map();
+                for (_, bits) in left_hm.iter_mut() {
+                    bits.push_front_bit(0);
+                }
+                let mut right_hm = right.to_bit_map();
+                for (_, bits) in right_hm.iter_mut() {
+                    bits.push_front_bit(1);
+                }
+                left_hm.extend(right_hm);
+                left_hm
+            },
+        }
+    }
+
+    pub fn put(&self) {
+        self.put_with_level(0);
+    }
+
+    fn put_with_level(&self, level: usize) {
+        match &self.content {
+            Content::Leaf(b) => {
+                print!("{} {}\n", self.occurences, b);
+            },
+            Content::Parent { left, right } => {
+                print!("NODE {}\n", self.occurences);
+                Tree::put_spaces(level);
+                print!("left: ");
+                left.put_with_level(level + 1);
+                Tree::put_spaces(level);
+                print!("right: ");
+                right.put_with_level(level + 1);
+            },
+        }
+    }
+
+    fn put_spaces(n: usize) {
+        for _ in 0..(n * 2) {
+            print!(" ");
+        }
+    }
+}
+
+use std::cmp::Ordering;
+
+impl Ord for Node {
+    fn cmp(&self, other: &Self) -> Ordering {
+        // self.occurences.cmp(&other.occurences)
+        other.occurences.cmp(&self.occurences) // dirty hack to fake min-heap
+    }
+}
+
+impl PartialOrd for Node {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Eq for Node {}
 
-// impl Tree {
-//     fn from_symbols(symbols: Symbols) -> Tree {
-//         symbols.0
-//     }
-// }
+impl PartialEq for Node {
+    fn eq(&self, other: &Self) -> bool {
+        self.occurences == other.occurences
+    }
+}