Convert Mouse-Input to Touch-Input..How??

This is the script for mouse input. Can someone please tell how to convert this for Andriod Touch Input???

using UnityEngine;
using System.Collections;

public class MouseDrag : MonoBehaviour
{
	
	public float speed = 1f; 

	private float baseAngle = 0.0f;
	private float maxRotaion = 80f;
	private Quaternion currentRotation,defaultRotation;	

	
	void Start()
	{
		defaultRotation = transform.rotation;
	}


	void OnMouseDown ()
		{


		var dir = Camera.main.WorldToScreenPoint (transform.position);
		dir = Input.mousePosition - dir;
		baseAngle = Mathf.Atan2(dir.y, dir.x) * Mathf.Rad2Deg;
		baseAngle -= Mathf.Atan2(transform.right.y, transform.right.x) * Mathf.Rad2Deg;
		}

		void OnMouseDrag ()
		{
		
		// Limit platform rotation
	
						var dir = Camera.main.WorldToScreenPoint (transform.position);
						dir = Input.mousePosition - dir;
						var angle = Mathf.Atan2 (dir.y, dir.x) * Mathf.Rad2Deg - baseAngle;
		if (angle >= -maxRotaion && angle <= maxRotaion)
						transform.rotation = Quaternion.AngleAxis (angle, Vector3.forward);

						currentRotation = transform.rotation;
		
				
}
		


	 

	void OnMouseUp()
	{ 
		StartCoroutine (RotateObject (transform, currentRotation, defaultRotation, 3.0f));
		
	}




	IEnumerator RotateObject(Transform thisTransform, Quaternion from, Quaternion to, float time)
	{
		float i = 0.0f;
		float rate = 1.0f / time;

		while (i < 1.0f) 
		{
			i += Time.deltaTime * rate * speed;

			transform.rotation = Quaternion.Slerp(from, to, i);
			yield return null;

		}
	}

}

I didn’t understand what are you trying to say about conversion. for single touch event I always use bellow approach

void Update ()
{

if (Application.platform == RuntimePlatform.IPhonePlayer || Application.platform == RuntimePlatform.Android)
{

		if (Input.touchCount > 0)
		{
			foreach (Touch touch in Input.touches)
			{
				if (touch.phase == TouchPhase.Began) 
				{
					_down_pos.x = touch.position.x;
					_down_pos.y = touch.position.y;
					_direction = Vector2.zero;
					
					RaycastHit2D hit = CastARay (touch.position);
					
					if (hit != null) 
					{
						if (hit.collider !=null)
						{
							
							OnDownGUIWidget(hit);
						}
					}
				}
				
	if(touch.phase == TouchPhase.Ended || touch.phase == TouchPhase.Canceled)
				{

					_up_pos.x = touch.position.x;
					_up_pos.y = touch.position.y;
				}
			}
			
		}
		

	}
	else
	{
		if (Input.GetMouseButtonDown(0))
		{
			_mouse_down = true;
			_direction = Vector2.zero;
			_down_pos.x = Input.mousePosition.x;
			_down_pos.y = Input.mousePosition.y;
			
			RaycastHit2D hit = CastARay (Input.mousePosition);
			
			if (hit != null) 
			{
				if (hit.collider !=null)
				{

					
					OnDownGUIWidget(hit);
				}
			}
		}
		
		
		if (Input.GetMouseButtonUp(0))
		{
			_up_pos.x = Input.mousePosition.x;
			_up_pos.y = Input.mousePosition.y;
			_mouse_down = false;
			

			
			OnClickGUIWidget(Input.mousePosition);
			
			
		}
		
	}