function [ M,ANNOTD,ATRTIMED ] = rdecg( PATH, filename,samples2read )

% 读取ECG信号，返回信号向量，专家标记，专家标记位置

% 

HEADERFILE= strcat(filename,'.hea');      

ATRFILE= strcat(filename,'.atr');         

DATAFILE=strcat(filename,'.dat');         

SAMPLES2READ=samples2read;          

fprintf(1,'\\n$> WORKING ON %s ...\n', HEADERFILE); 

signalh= fullfile(PATH, HEADERFILE);    

fid1=fopen(signalh,'r');    

z= fgetl(fid1);             

A= sscanf(z, '%*s %d %d %d',[1,3]); 

nosig= A(1);    

sfreq=A(2);     

clear A;        

for k=1:nosig         

    z= fgetl(fid1);

    A= sscanf(z, '%*s %d %d %d %d %d',[1,5]);

    dformat(k)= A(1);           

    gain(k)= A(2);              

    bitres(k)= A(3);           

    zerovalue(k)= A(4);         

    firstvalue(k)= A(5);        

end

fclose(fid1);

clear A;

if dformat~= [212,212], error('this script does not apply binary formats different to 212.'); end

signald= fullfile(PATH, DATAFILE);           

fid2=fopen(signald,'r');

A= fread(fid2, [3, SAMPLES2READ], 'uint8')';  

fclose(fid2);

M2H= bitshift(A(:,2), -4);        

M1H= bitand(A(:,2), 15);          

PRL=bitshift(bitand(A(:,2),8),9);     

PRR=bitshift(bitand(A(:,2),128),5);   

M( : , 1)= bitshift(M1H,8)+ A(:,1)-PRL;

M( : , 2)= bitshift(M2H,8)+ A(:,3)-PRR;

if M(1,:) ~= firstvalue, error('inconsistency in the first bit values'); end

switch nosig

case 2

    M( : , 1)= (M( : , 1)- zerovalue(1))/gain(1);

    M( : , 2)= (M( : , 2)- zerovalue(2))/gain(2);

    TIME=(0:(SAMPLES2READ-1))/sfreq;

case 1

    M( : , 1)= (M( : , 1)- zerovalue(1));

    M( : , 2)= (M( : , 2)- zerovalue(1));

    M=M';

    M(1)=[];

    sM=size(M);

    sM=sM(2)+1;

    M(sM)=0;

    M=M';

    M=M/gain(1);

    TIME=(0:2*(SAMPLES2READ)-1)/sfreq;

otherwise  

    disp('Sorting algorithm for more than 2 signals not programmed yet!');

end

clear A M1H M2H PRR PRL;

fprintf(1,'\\n$> LOADING DATA FINISHED \n');

atrd= fullfile(PATH, ATRFILE);      

fid3=fopen(atrd,'r');

A= fread(fid3, [2, inf], 'uint8')';

fclose(fid3);

ATRTIME=[];

ANNOT=[];

sa=size(A);

saa=sa(1);

i=1;

while i<=saa

    annoth=bitshift(A(i,2),-2);

    if annoth==59

        ANNOT=[ANNOT;bitshift(A(i+3,2),-2)];

        ATRTIME=[ATRTIME;A(i+2,1)+bitshift(A(i+2,2),8)+...

                bitshift(A(i+1,1),16)+bitshift(A(i+1,2),24)];

        i=i+3;

    elseif annoth==60

        % nothing to do!

    elseif annoth==61

        % nothing to do!

    elseif annoth==62

        % nothing to do!

    elseif annoth==63

        hilfe=bitshift(bitand(A(i,2),3),8)+A(i,1);

        hilfe=hilfe+mod(hilfe,2);

        i=i+hilfe/2;

    else

        ATRTIME=[ATRTIME;bitshift(bitand(A(i,2),3),8)+A(i,1)];

        ANNOT=[ANNOT;bitshift(A(i,2),-2)];

    end

   i=i+1;

end

ANNOT(length(ANNOT))=[];       

ATRTIME(length(ATRTIME))=[];  

clear A;

ATRTIME= (cumsum(ATRTIME))/sfreq;

ind= find(ATRTIME <= TIME(end));

ATRTIMED= ATRTIME(ind);

ANNOT=round(ANNOT);

ANNOTD= ANNOT(ind);

% -------------------------------------------------------------------------

fprintf(1,'\\n$> ALL FINISHED \n');

end