package ifc.bim.openecg.jtools.jparser;
/**
 * <p>Title: SCP-ECG Section Header</p>
 * <p>Description: The structure of a generic section, with methods to load header and data part from a file</p>
 * <p>Company: Ist. Fisiologia Clinica del CNR via G.Moruzzi,1 54124 Pisa Italy</p>
 * @authors Giacomo Ciani - Fabrizio Conforti (conforti@ifc.cnr.it)
 * @version 1.0
 */
import  java.io.*;
import  java.nio.*;
import  java.util.*;
import	java.util.logging.*;
import  javax.imageio.stream.*;
/**
 * The structure of a generic section, with methods to load header and data part from a file
 */
public class SectGen {
/** Stores the section's header*/
	public SectHeader	head;
/** Stores the section's data part*/
	public byte[]		data;
/** Log error and info messages produced during the section's load operation*/
	public Logger		log;
/** The start index for reading operations*/
    public int			indx;
/**
 * Constructs a SectGen with an anonymous logger
 */
	public SectGen(){
		this( Logger.getAnonymousLogger() );
	}
/**
 * Constructs a SectGen that uses a specific logger
 * @param log the logger to be used
 */
	public SectGen(Logger log){
		this.log=log;
		head = new SectHeader();
	}
/**
 * Reads a byte from "data" starting at index "indx", and returns it as a byte value.
 * @return A byte value
 * @throws IndexOutOfBoundsException if the index "idx" is greater tha the array length.
 */
	public byte readByte(){
		return data[indx++];
	}
/**
 * Reads two bytes from "data" starting at index "indx", and (conceptually) concatenates
 * them according to Little Endian byte order, and returns the result as a short value.
 * @return A short value
 * @throws IndexOutOfBoundsException if the end of the array is reached before all bytes are read.
 */
	public short readShort(){
		int lsb=data[indx++];
		int hsb=data[indx++];
		return (short)(256*hsb+(0x000000ff&lsb));
	}
/**
 * Reads four bytes from "data" starting at index "indx", and (conceptually) concatenates
 * them according to Little Endian byte order, and returns the result as an int value.
 * @return An int value
 * @throws IndexOutOfBoundsException if the end of the array is reached before all bytes are read.
 */
	public int readInt(){
		int lsb=readShort();
		int hsb=readShort();
		return (65536*hsb+(0x0000ffff&lsb));
	}
/**
 * Reads "dest.len" bytes from "data" starting at index "idx", and stores them into "dest".
 *  If the end of the "data" array is reached, an EOFException will be thrown.
 * @param dest an array of bytes
 * @throws IndexOutOfBoundsException if the stream reaches the end before reading all the bytes.
 * Bytes already read are stored anyway.
 */
	public void readFully(byte[] dest) {
		for (int i=0; i<dest.length; i++) dest[i]=data[indx++];
	}
/**
 * Retrieves the header and data part of the section from the specified FileImageOutputStream
 * starting at index "idx" and stores them in the "head" and "data" variables.
 * @param fHandle a FileImageInputStream pointing at the source file
 * @param idx an int representing the index of the first byte of the section in the source file.
 * @throws Exception if the operation fails
 */
	public void Load ( FileImageOutputStream fHandle, int idx ) throws Exception{
		try{
			fHandle.seek(idx-1);
			head.Load(fHandle);
		}catch(Exception ex){
			log.warning("unable to load header");
			throw new Exception("unable to load header");
		}
		head.Print();
		try{
			data   = new byte[head.dataLen];
			fHandle.readFully(data);
			indx= 0;
		}catch(Exception ex){
			log.warning("unable to load data part");
			throw new Exception("unable to load data part");
		}
	}
/**
 * An empty method to be overridden by classes that extends this one.
 * @param lNum total number of leads stored in the SCP-ECG record (irrilevant for some sections)
 * @throws Exception if any error occurs
 */
	public void Parse(int lNum) throws Exception{} // could be abstract?
/**
 * An empty method to be overridden by classes that extends this one.
 */
	public void PrnInfo() {} // could be abstract?
/**	to be completed **********************************
	public void Save ( FileImageOutputStream fHandle, int idx ) throws Exception{
		//crc computing and storing
		try{
			fHandle.seek(idx-1);
			//header writing
		}catch(Exception ex){
			throw new Exception("unable to save header");
		}
		try{
			//datapart writing
		}catch(Exception ex){
			throw new Exception("unable to save data part");
		}
	}
	private int CrcCalc() {
		return 0;
	}
	public boolean CrcTest() {
		return(head.sectCrc==CrcCalc());
	}
***	to be completed ***********************************/
}