isf read

isfread.m

function [rtnData, headData] = isfread (filename)
% * Written 1/25/2009 by Wenwei Qiao *
% * modified by Dzone 140624_10:40  *
fileID = fopen(filename,'r');

% read ASCII header
header_tmp = fread(fileID, 500)';
header = char(header_tmp);

headData = parseHead(header);

fseek(fileID, 0, 'eof');
dataOffset =  - headData.NR_P*headData.BYT_N;
fseek(fileID, dataOffset, 'cof');

if (headData.BYT_N==1)
    inData = fread(fileID, headData.NR_P, 'int8');
else
    inData = fread(fileID, headData.NR_P, 'int16',  'ieee-be');
end

fclose(fileID);

lowerXLimit = headData.XZE;
upperXLimit = ((headData.NR_P-1)* headData.XIN  + headData.XZE);
rtnData.x   = [lowerXLimit : headData.XIN : upperXLimit]';
rtnData.y   = headData.YMU*(inData-headData.YOF) + headData.YZE;



% parseHead - used to parse and convert the header data into a more
% useful structure.
function headData = parseHead(header)

headData.NR_P       = getParamNum(header, 'NR_PT'    );
headData.BYT_N  = getParamNum(header, 'BYT_NR' );
headData.BIT_N  = getParamNum(header, 'BIT_NR' );
headData.XIN  = getParamNum(header, 'XINCR'   );
headData.XZE  = getParamNum(header, 'XZERO'   );
headData.PT_O  = getParamNum(header, 'PT_OFF'  );
headData.YMU  = getParamNum(header, 'YMULT'   );
headData.YOF  = getParamNum(header, 'YOFF'   );
headData.YZE  = getParamNum(header, 'YZERO'   );
headData.YSCALE  = getParamNum(header, 'VSCALE' );
headData.HSCALE  = getParamNum(header, 'HSCALE' );
headData.YPOS   = getParamNum(header, 'VPOS' );
headData.YOFFSET = getParamNum(header, 'VOFFSET' );
headData.HDELAY  = getParamNum(header, 'HDELAY' );

headData.ENC        = getParamStr(header, 'ENCDG',   ';');
headData.BN_F       = getParamStr(header, 'BN_FMT',  ';');
headData.BYT_O      = getParamStr(header, 'BYT_OR', ';');
headData.WFI        = getParamStr(header, 'WFID',   '"');
headData.PT_F       = getParamStr(header, 'PT_FMT',  ';');
headData.XUN        = getParamStr(header, 'XUNIT',   '"');
headData.YUN        = getParamStr(header, 'YUNIT',   '"');

headData.CURV       = getCurvNum(header);

function rtnNum = getParamNum (headStr, cmdStr)
cmdLoc = findstr(headStr, cmdStr);
if (cmdLoc)
    headStr_tmp     = headStr(cmdLoc(1)+length(cmdStr)+1 : length(headStr)) ;
    [tmp, remJunk]  = strtok(headStr_tmp,';') ;
    rtnNum          = str2num(tmp);
else
    rtnNum =[];
end


function rtnStr = getParamStr(headStr, cmdStr, dlm)
cmdLoc = findstr(headStr, cmdStr);
if (cmdLoc)
    headStr_tmp     = headStr(cmdLoc(1)+length(cmdStr)+1 : length(headStr)) ;
    [rtnStr,remStr] = strtok(headStr_tmp, dlm) ;
else
    rtnStr=[];
end


function rtnNum = getCurvNum (headStr)
cmdStr='CURV #';
cmdLoc = findstr(headStr, cmdStr);
if (cmdLoc)
    headStr_tmp     = headStr(cmdLoc(1)+length(cmdStr) : length(headStr)) ;
    curvNum_tmp     = headStr_tmp(1);
    curvNum         = str2num(curvNum_tmp);
    tmp             = headStr_tmp(2:curvNum+1) ;
    rtnNum          = str2num(tmp);
else
    rtnNum=[];
end