From ae09c8d23287c8eb64d3eba45273a425192406b2 Mon Sep 17 00:00:00 2001
From: gandalfr-ky <oukanimiso@gmail.com>
Date: Thu, 7 Mar 2024 09:28:37 +0000
Subject: [PATCH] added boundary check

---
 qulacs/gate/gate_npair_qubit.cpp            |  2 ++
 qulacs/gate/gate_one_control_one_target.cpp |  4 ++++
 qulacs/gate/gate_one_qubit.cpp              | 18 ++++++++++++++++++
 qulacs/gate/gate_quantum_matrix.cpp         |  3 +++
 qulacs/gate/gate_two_qubit.cpp              |  2 ++
 qulacs/gate/update_ops.hpp                  |  7 +++++++
 6 files changed, 36 insertions(+)

diff --git a/qulacs/gate/gate_npair_qubit.cpp b/qulacs/gate/gate_npair_qubit.cpp
index a91b6255..25ee8791 100644
--- a/qulacs/gate/gate_npair_qubit.cpp
+++ b/qulacs/gate/gate_npair_qubit.cpp
@@ -5,6 +5,8 @@
 namespace qulacs {
 namespace internal {
 void FusedSwapGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_qubit_index1 + this->_block_size - 1);
+    check_qubit_within_bounds(state_vector, this->_qubit_index2 + this->_block_size - 1);
     fusedswap_gate(this->_qubit_index1, this->_qubit_index2, this->_block_size, state_vector);
 }
 }  // namespace internal
diff --git a/qulacs/gate/gate_one_control_one_target.cpp b/qulacs/gate/gate_one_control_one_target.cpp
index 6fa42fb4..adfcd16d 100644
--- a/qulacs/gate/gate_one_control_one_target.cpp
+++ b/qulacs/gate/gate_one_control_one_target.cpp
@@ -5,10 +5,14 @@
 namespace qulacs {
 namespace internal {
 void CXGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_control);
+    check_qubit_within_bounds(state_vector, this->_target);
     cx_gate(this->_control, this->_target, state_vector);
 }
 
 void CZGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_control);
+    check_qubit_within_bounds(state_vector, this->_target);
     cz_gate(this->_control, this->_target, state_vector);
 }
 }  // namespace internal
diff --git a/qulacs/gate/gate_one_qubit.cpp b/qulacs/gate/gate_one_qubit.cpp
index 428f4197..3465adf8 100644
--- a/qulacs/gate/gate_one_qubit.cpp
+++ b/qulacs/gate/gate_one_qubit.cpp
@@ -10,74 +10,92 @@ Gate SqrtXGateImpl::get_inverse() const { return std::make_shared<SqrtXdagGateIm
 Gate SqrtYGateImpl::get_inverse() const { return std::make_shared<SqrtYdagGateImpl>(_target); }
 
 void IGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     i_gate(this->_target, state_vector);
 }
 
 void XGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     x_gate(this->_target, state_vector);
 }
 
 void YGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     y_gate(this->_target, state_vector);
 }
 
 void ZGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     z_gate(this->_target, state_vector);
 }
 
 void HGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     h_gate(this->_target, state_vector);
 }
 
 void SGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     s_gate(this->_target, state_vector);
 }
 
 void SdagGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     sdag_gate(this->_target, state_vector);
 }
 
 void TGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     t_gate(this->_target, state_vector);
 }
 
 void TdagGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     tdag_gate(this->_target, state_vector);
 }
 
 void SqrtXGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     sqrtx_gate(this->_target, state_vector);
 }
 
 void SqrtXdagGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     sqrtxdag_gate(this->_target, state_vector);
 }
 
 void SqrtYGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     sqrty_gate(this->_target, state_vector);
 }
 
 void SqrtYdagGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     sqrtydag_gate(this->_target, state_vector);
 }
 
 void P0GateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     p0_gate(this->_target, state_vector);
 }
 
 void P1GateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     p1_gate(this->_target, state_vector);
 }
 
 void RXGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     rx_gate(this->_target, this->_angle, state_vector);
 }
 
 void RYGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     ry_gate(this->_target, this->_angle, state_vector);
 }
 
 void RZGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     rz_gate(this->_target, this->_angle, state_vector);
 }
 }  // namespace internal
diff --git a/qulacs/gate/gate_quantum_matrix.cpp b/qulacs/gate/gate_quantum_matrix.cpp
index 487e8efc..0618eef0 100644
--- a/qulacs/gate/gate_quantum_matrix.cpp
+++ b/qulacs/gate/gate_quantum_matrix.cpp
@@ -3,14 +3,17 @@
 namespace qulacs {
 namespace internal {
 void U1GateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     u_gate(this->_target, this->_matrix, state_vector);
 }
 
 void U2GateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     u_gate(this->_target, this->_matrix, state_vector);
 }
 
 void U3GateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target);
     u_gate(this->_target, this->_matrix, state_vector);
 }
 }  // namespace internal
diff --git a/qulacs/gate/gate_two_qubit.cpp b/qulacs/gate/gate_two_qubit.cpp
index 70eac3b9..f7ab2b8d 100644
--- a/qulacs/gate/gate_two_qubit.cpp
+++ b/qulacs/gate/gate_two_qubit.cpp
@@ -5,6 +5,8 @@
 namespace qulacs {
 namespace internal {
 void SwapGateImpl::update_quantum_state(StateVector& state_vector) const {
+    check_qubit_within_bounds(state_vector, this->_target1);
+    check_qubit_within_bounds(state_vector, this->_target2);
     swap_gate(this->_target1, this->_target2, state_vector);
 }
 }  // namespace internal
diff --git a/qulacs/gate/update_ops.hpp b/qulacs/gate/update_ops.hpp
index 04184ab1..6932ae2f 100644
--- a/qulacs/gate/update_ops.hpp
+++ b/qulacs/gate/update_ops.hpp
@@ -6,6 +6,13 @@
 
 namespace qulacs {
 namespace internal {
+inline void check_qubit_within_bounds(const StateVector& state, UINT op_qubit) {
+    if (op_qubit >= state.n_qubits()) [[unlikely]] {
+        throw std::runtime_error(
+            "Target/Control qubit exceeds the number of qubits in the system.");
+    }
+}
+
 void i_gate(UINT target_qubit_index, StateVector& state);
 
 void x_gate(UINT target_qubit_index, StateVector& state);