lock camera boundaries when pinch-zoomed

Hi all, this is my first game and i'm making a 2d board game. i found a script for a (clash of clans's type) pinch zoom. and another script for finding the boundaries of camera. now i can't figure how to lock the camera so that when you move around you don't go off map!

 using UnityEngine;
 
 public class PinchZoom : MonoBehaviour
 {
     public float moveSensitivityX = 1.0f;
     public float moveSensitivityY = 1.0f;
     public bool updateZoomSensitivity = true;
     public float orthoZoomSpeed = 0.05f;
     public float minZoom = 1.0f;
     public float maxZoom = 20.0f;
     public bool invertMoveX =  false;
     public bool invertMoveY =  false;
 
     float positionY = 0;
     float positionX = 0;
 
     //float tempY = 0;
 
     private Camera _camera;
     void Start(){
 
 _camera = Camera.main;
     }
     
     void Update()
     {
         float screenAspect = (float)Screen.width / (float)Screen.height;
         float cameraHeight = _camera.orthographicSize * 2;
         Bounds bounds = new Bounds(
             _camera.transform.position,
             new Vector3(cameraHeight * screenAspect, cameraHeight, 0));
         //Debug.Log (bounds.max);
 
         if (updateZoomSensitivity) {
         
             moveSensitivityX = _camera.orthographicSize / 5.0f;
 
             moveSensitivityY = _camera.orthographicSize / 5.0f;
 
         }
 
         Touch[] touches = Input.touches;
         if (touches.Length > 0) {
             //Single Touch(move)
             if(touches.Length == 1){
 
                 if(touches[0].phase == TouchPhase.Moved){
                     Vector2 delta  = touches[0].deltaPosition;
                      positionX = delta.x * moveSensitivityX * Time.deltaTime;
                     positionX = invertMoveX ? positionX : positionX * -1;
                     
                     //if(bounds.max.y < 703){
                         positionY = delta.y * moveSensitivityY * Time.deltaTime;
 
 
                     positionY = invertMoveY ? positionY : positionY * -1;
                     _camera.transform.position += new Vector3 (positionX,positionY,0);
 
 
 
                 }
                 
             }
             //double touch(zoom)
             if(touches.Length == 2){
                 
                 Touch touchOne = touches[0];
                 Touch touchTwo = touches[1];
                 Vector2 touchOnePreviousPosition = touchOne.position - touchOne.deltaPosition;
                 Vector2 touchTwoPreviousPosition = touchTwo.position - touchTwo.deltaPosition;
                 float prevTouchDeltaMag = (touchOnePreviousPosition - touchTwoPreviousPosition).magnitude;
                 float touchDeltaMag = (touchOne.position - touchTwo.position).magnitude;
                 float deltaMagDiff = prevTouchDeltaMag - touchDeltaMag;
                 _camera.orthographicSize += deltaMagDiff * orthoZoomSpeed;
                 _camera.orthographicSize = Mathf.Clamp(_camera.orthographicSize, minZoom, maxZoom);
 
                 
             }
         
         }
     }
 
 }