feat: op_depth

src/compiler.cairo

@@ -1,3 +1,4 @@
+use core::dict::Felt252DictTrait;
 use shinigami::opcodes::Opcode;
 
 // Compiler that takes a Bitcoin Script program and compiles it into a bytecode
@@ -21,6 +22,7 @@ pub impl CompilerTraitImpl of CompilerTrait {
         opcodes.insert('OP_0', Opcode::OP_0);
         opcodes.insert('OP_1', Opcode::OP_1);
         opcodes.insert('OP_ADD', Opcode::OP_ADD);
+        opcodes.insert('OP_DEPTH', Opcode::OP_DEPTH);
         Compiler { opcodes }
     }
 

src/opcodes/opcodes.cairo

@@ -2,6 +2,7 @@ pub mod Opcode {
     pub const OP_0: u8 = 0;
     pub const OP_1: u8 = 81;
     pub const OP_ADD: u8 = 147;
+    pub const OP_DEPTH: u8 = 116;
 
     use shinigami::engine::Engine;
     use shinigami::stack::ScriptStackTrait;
@@ -123,7 +124,7 @@ pub mod Opcode {
             113 => not_implemented(ref engine),
             114 => not_implemented(ref engine),
             115 => not_implemented(ref engine),
-            116 => not_implemented(ref engine),
+            116 => opcode_depth(ref engine),
             117 => not_implemented(ref engine),
             118 => not_implemented(ref engine),
             119 => not_implemented(ref engine),
@@ -174,6 +175,11 @@ pub mod Opcode {
         engine.dstack.push_int(a + b);
     }
 
+    fn opcode_depth(ref engine: Engine) {
+        let depth: i64 = engine.dstack.len().into();
+        engine.dstack.push_int(depth);
+    }
+
     fn not_implemented(ref engine: Engine) {
         panic!("Opcode not implemented");
     }

src/opcodes/tests/test_opcodes.cairo

@@ -51,3 +51,59 @@ fn test_op_add() {
     let expected_stack = array!["\0\0\0\0\0\0\0\x02"];
     assert_eq!(dstack, expected_stack.span(), "Stack is not equal to expected");
 }
+
+#[test]
+fn test_op_depth_empty_stack() {
+    let program = "OP_DEPTH";
+    let mut compiler = CompilerTraitImpl::new();
+    let bytecode = compiler.compile(program);
+    let mut engine = EngineTraitImpl::new(bytecode);
+
+    let res = engine.step();
+    assert!(res, "Execution of step failed");
+
+    let dstack = engine.get_dstack();
+    assert_eq!(dstack.len(), 1, "Stack length is not 1");
+
+    let expected_stack = array!["\0\0\0\0\0\0\0\0"];
+    assert_eq!(dstack, expected_stack.span(), "Stack is not equal to expected for empty stack");
+}
+
+#[test]
+fn test_op_depth_one_item() {
+    let program = "OP_1 OP_DEPTH";
+    let mut compiler = CompilerTraitImpl::new();
+    let bytecode = compiler.compile(program);
+    let mut engine = EngineTraitImpl::new(bytecode);
+
+    let _ = engine.step();
+    let res = engine.step();
+    assert!(res, "Execution of step failed");
+
+    let dstack = engine.get_dstack();
+    assert_eq!(dstack.len(), 2, "Stack length is not 2");
+
+    let expected_stack = array!["\0\0\0\0\0\0\0\x01", "\0\0\0\0\0\0\0\x01"];
+    assert_eq!(dstack, expected_stack.span(), "Stack is not equal to expected for one item");
+}
+
+#[test]
+fn test_op_depth_multiple_items() {
+    let program = "OP_1 OP_1 OP_ADD OP_1 OP_DEPTH";
+    let mut compiler = CompilerTraitImpl::new();
+    let bytecode = compiler.compile(program);
+    let mut engine = EngineTraitImpl::new(bytecode);
+
+    let _ = engine.step();
+    let _ = engine.step();
+    let _ = engine.step();
+    let _ = engine.step();
+    let res = engine.step();
+    assert!(res, "Execution of step failed");
+
+    let dstack = engine.get_dstack();
+    assert_eq!(dstack.len(), 3, "Stack length is not 3");
+
+    let expected_stack = array!["\0\0\0\0\0\0\0\x02", "\0\0\0\0\0\0\0\x01", "\0\0\0\0\0\0\0\x02"];
+    assert_eq!(dstack, expected_stack.span(), "Stack is not equal to expected for multiple items");
+}