1 files changed, 44 insertions, 0 deletions
diff --git a/src/grossmeister/ttable.rs b/src/grossmeister/ttable.rs
new file mode 100644
index 0000000..4bf2398
--- /dev/null
+++ b/src/grossmeister/ttable.rs
@@ -0,0 +1,44 @@
+use crate::moves::Move;
+
+use super::Grossmeister;
+
+/// https://www.chessprogramming.org/Node_Types
+#[derive(Debug, PartialEq, Clone, Copy)]
+pub enum NodeType {
+    /// Principal variation node - exact score
+    PV,
+    /// Fail-high
+    Cut,
+    /// Fail-low
+    All,
+}
+
+#[derive(Debug, PartialEq, Clone, Copy)]
+pub struct TranspositionTableItem {
+    /// Zobrist hash of this position
+    pub hash: u64,
+    pub mov: Move,
+    pub depth: u8,
+    pub score: f32,
+    pub node_type: NodeType,
+}
+
+pub const TTABLE_SIZE: u64 = 2u64.pow(24);
+pub type TranspositionTable = Vec<Option<TranspositionTableItem>>;
+
+
+impl Grossmeister {
+    /// Find current transposition in Transposition Table
+    pub fn transposition(&self) -> Option<TranspositionTableItem> {
+        match self.transposition_table[(self.board.hash % TTABLE_SIZE) as usize] {
+            Some(item) => {
+                if item.hash == self.board.hash {
+                    return Some(item)
+                }
+                None
+            }
+            None => None
+        }
+    }
+
+}