%sFtpRead_ishne
%read ECG data from ISHNE ecgSig file
%
%in------------------------------------------------------------------------
%fileName:    the ishne filename including the path
%startOffset: the start offset to read ecgSig
%length:      length of ecgSig to read (in seconds)
%
%out-----------------------------------------------------------------------
%ecgSig : ECG signal
%##########################################################################

function [ishneHeader, ecgSig]=sFtpRead_ishne(fileName, sFtpClient, startOffset, length);
fid = sFtpFopen(fileName, sFtpClient);
if ne(fid,-1)
    
    %magicNumber
    magicNumber = sFtpFread( fid, sFtpClient, 8, 'uchar');
   
    % get checksum
	checksum = sFtpFread( fid, sFtpClient, 1, 'uint16');
	
	%read header
    Var_length_block_size = sFtpFread( fid, sFtpClient, 1, 'long');
    ishneHeader.Sample_Size_ECG = sFtpFread( fid, sFtpClient, 1, 'long');
    Offset_var_lenght_block = sFtpFread( fid, sFtpClient, 1, 'long');
    Offset_ECG_block = sFtpFread( fid, sFtpClient, 1, 'long');
    File_Version = sFtpFread( fid, sFtpClient, 1, 'short');
    First_Name = sFtpFread( fid, sFtpClient, 40, 'uchar');
    Last_Name = sFtpFread( fid, sFtpClient, 40, 'uchar');
    ID = sFtpFread( fid, sFtpClient, 20, 'uchar');
    Sex = sFtpFread( fid, sFtpClient, 1, 'short');
    Race = sFtpFread( fid, sFtpClient, 1, 'short');
    Birth_Date = sFtpFread( fid, sFtpClient, 3, 'short');
    Record_Date = sFtpFread( fid, sFtpClient, 3, 'short');
    File_Date = sFtpFread( fid, sFtpClient, 3, 'short');
    Start_Time = sFtpFread( fid, sFtpClient, 3, 'short');
    ishneHeader.nbLeads = sFtpFread( fid, sFtpClient, 1, 'short');
    Lead_Spec = sFtpFread( fid, sFtpClient, 12, 'short');
    Lead_Qual = sFtpFread( fid, sFtpClient, 12, 'short');
    ishneHeader.Resolution = sFtpFread( fid, sFtpClient, 12, 'short');
    Pacemaker = sFtpFread( fid, sFtpClient, 1, 'short');
    Recorder = sFtpFread( fid, sFtpClient, 40, 'uchar');
    ishneHeader.Sampling_Rate = sFtpFread( fid, sFtpClient, 1, 'short');
    Proprietary = sFtpFread( fid, sFtpClient, 80, 'uchar');
    Copyright = sFtpFread( fid, sFtpClient, 80, 'uchar');
    Reserved = sFtpFread( fid, sFtpClient, 88, 'uchar');
     
    % read variable_length block
    varblock = sFtpFread( fid, sFtpClient, Var_length_block_size, 'char');
    
    % get data at start
    offset = int32(startOffset*ishneHeader.Sampling_Rate*ishneHeader.nbLeads*2); % each data has 2 bytes
    sFtpFseek(fid, sFtpClient, Offset_ECG_block+offset, 'bof');
    
    
    % read ecgSig signal
    numSample = length*double(ishneHeader.Sampling_Rate);
    ecgSig = sFtpFread( fid, sFtpClient, [double(ishneHeader.nbLeads), numSample], 'int16')';
    sFtpFclose(fid, sFtpClient);
 else
    ihsneHeader = [];
    ecgSig=[];
 end