Initial commit: Rewrite in Rust

3 files changed, 156 insertions, 0 deletions

diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..2b4e6c5
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,12 @@
+use std::env;
+
+pub mod symbols;
+// pub mod tree;
+//
+use symbols::Tree;
+
+fn main() {
+    let file_path = env::args().nth(1).unwrap();
+    let tree = Tree::from_file(&file_path).unwrap();
+    tree.put();
+}
diff --git a/src/symbols.rs b/src/symbols.rs
new file mode 100644
index 0000000..cd8fd52
--- /dev/null
+++ b/src/symbols.rs
@@ -0,0 +1,122 @@
+use std::fs;
+use std::io;
+use std::io::Read;
+use std::collections::{BinaryHeap, HashMap};
+
+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(u8),
+    Parent {
+        left:  Box<Node>,
+        right: Box<Node>,
+    },
+}
+
+pub type Tree = Node;
+
+impl Tree {
+    pub fn from_file(file_path: &str) -> io::Result<Tree> {
+        let mut symbols = Symbols::from_file(file_path)?;
+        Ok(Tree::from_symbols(&mut symbols))
+    }
+
+    fn from_symbols(symbols: &mut Symbols) -> Tree {
+        while symbols.0.len() >= 2 {
+            let first = symbols.0.pop().unwrap();
+            let second = symbols.0.pop().unwrap();
+            let n = Node::join(first, second);
+            symbols.0.push(n);
+        }
+        let ret = symbols.0.pop().unwrap();
+        ret
+    }
+
+    pub fn put(&self) {
+        self.put_with_level(0);
+    }
+
+    fn put_with_level(&self, level: usize) {
+        match &self.content {
+            Content::Leaf(b) => {
+                // Tree::put_spaces(level);
+                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!(" ");
+        }
+    }
+}
+
+struct Symbols(BinaryHeap<Node>);
+
+impl Symbols {
+    fn from_file(file_path: &str) -> io::Result<Symbols> {
+        let f = fs::File::open(file_path)?;
+        let mut counter: HashMap<u8, usize> = HashMap::new();
+        for b in f.bytes() {
+            let k = b?;
+            let v = match counter.get(&k) {
+                Some(count) => count + 1,
+                None        => 1,
+            };
+            counter.insert(k, v);
+        }
+        let heap: BinaryHeap<Node> = counter
+            .iter()
+            .map(|(k, v)| Node { occurences: *v, content: Content::Leaf(*k) })
+            .collect();
+        Ok(Symbols(heap))
+    }
+}
+
+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 for min-heap
+    }
+}
+
+impl PartialOrd for Node {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Eq for Node {}
+
+impl PartialEq for Node {
+    fn eq(&self, other: &Self) -> bool {
+        self.occurences == other.occurences
+    }
+}
diff --git a/src/tree.rs b/src/tree.rs
new file mode 100644
index 0000000..d3cca22
--- /dev/null
+++ b/src/tree.rs
@@ -0,0 +1,22 @@
+use super::symbols::Symbols;
+
+struct Node {
+    occurence: usize,
+    content: Content,
+}
+
+enum Content {
+    Leaf(i8),
+    Parent {
+        left: Box<Node>,
+        right: Box<Node>,
+    },
+}
+
+type Tree = Node;
+
+// impl Tree {
+//     fn from_symbols(symbols: Symbols) -> Tree {
+//         symbols.0
+//     }
+// }