psychtoolbox-3-common 3.0.11.20140816.dfsg1-1 / usr / share / psychtoolbox-3 / PsychFiles / ReadStructsFromText.m

function theStructs = ReadStructsFromText(filename)
% theStructs = ReadStructsFromText(filename)
%
% Open a tab delimited text file.  The first row should
% contain the field names for a structure.  Each following
% row contains the data for one instance of that structure.
%
% This routine reads each row and returns an array of structures,
% one struct for each row, with the data filled in.  Data
% can be numeric or string for each field.
%
% Not a lot of checking is done for cases where the read file
% fails to conform to the necessary format.
%
% See Also: WriteStructsToText

% 6/15/03   dhb			Wrote it.
% 07/01/03  dhb 		Support string as well as numeric data.
% 07/02/03	dhb, jg     Handle white space in column headers.
% 07/03/03  dhb         More little tweaks.
% 08/06/03  dhb         Handle fgetl returns empty string.
% 08/22/07  dhb         This was modified on disk but not commented our uploaded to SVN repository.
% 4/26/12   dhb         Squeeze '/' out of field names too.
% 5/31/12   dhb         Squeeze '*' out of field names too.
% 6/7/13    dhb         Suppress uninteresting warning on str2num.
% 4/3/14    dhb         Try to handle NaN in text files.  Worked for at least one case.

% Open the file
fid = fopen(filename);
if fid == -1
	error('Cannot open file %s', filename);
end

% Read first line to get field names for returned structure
theFields = {};
firstLine = fgetl(fid);
theIndex = 1;
i = 1;
while (1)
	wholeField = [];
	while (1)
		readString = firstLine(theIndex:end);
		[field,count,nil,nextIndex] = sscanf(readString,'%s',1);
		if (count == 0)
			break;
		end
		wholeField = [wholeField field];
		theIndex = theIndex+nextIndex-1;
		if (nextIndex <= length(readString) && abs(readString(nextIndex)) == 9)
			break;
		else
			wholeField = [wholeField ' '];
		end
	end
	if (count == 0)
		if (~isempty(wholeField))
			theFields{i} = wholeField;
			i = i+1;
		end
		break;
	end
	theFields{i} = wholeField;
	wholeField = [];
	i = i+1;
end
nFields = length(theFields);

% Squeeze white space out of each field
for i = 1:nFields
	newField = [];
	oldField = theFields{i};
	for j = 1:length(oldField)
		if (~isspace(oldField(j)) && oldField(j) ~= '.' && oldField(j) ~= '/' && oldField(j) ~= '*')
			newField = [newField oldField(j)];
		end
	end
	theFields{i} = newField;
end

% Octave doesn't support the textscan function, so we use the old method
% of extracting data for Octave users.  The new method allows spaces in
% strings.
if ~IsOctave
	% Read out all the data from the text file delimited by newline
	% characters.
	data = textscan(fid, '%s', 'delimiter', '\n');
	data = data{1};
	
	% Read the values from each line of the text and convert them to
	% doubles if possible.
	f = 1;
	for i = 1:size(data, 1)
		values = textscan(data{i}, '%s', 'delimiter', '\t');
		values = values{1};

		for j = 1:size(values, 1)
			convertedValue = [];
			
			% Convert the entry from a string to a number if possible.  We
			% first check to see if the value is on the path as a function
			% because the str2num function calls eval on its input which
			% will cause it to execute.
            if (strcmp(lower(values{j}),'nan'))
                convertedValue = NaN;
            elseif isempty(which(values{j})) && isempty(which(strtok(values{j})))
                oldWarn = warning('off','MATLAB:namelengthmaxexceeded');
				convertedValue = str2num(values{j}); %#ok<ST2NM>
                warning(oldWarn.state,'MATLAB:namelengthmaxexceeded');
			end

			% If the value successfully converted, overwrite what was
			% already in the cell array.
			if ~isempty(convertedValue)
				values{j} = convertedValue;
			end
		end
		
		theStructs(f) = cell2struct(values, theFields, 1); %#ok<AGROW>
		f = f + 1;
	end
else
	% Now read lines and pull out structure elements
	f = 1;
	while (1)
		theLine = fgetl(fid);
		if (isempty(theLine) || theLine == -1)
			break;
		end
		theIndex = 1;
		theData = cell(nFields,1);
		for i = 1:nFields
			readString = theLine(theIndex:end);
			[field,count,nil,nextIndex] = sscanf(readString,'%g',1);
			if (count == 0)
				[field,count,nil,nextIndex] = sscanf(readString,'%s',1);
				if (count == 0)
					error('Cannot parse input');
				end
			end
			theIndex = theIndex+nextIndex-1;
			theData{i} = field;
		end
		theStruct = cell2struct(theData,theFields,1);
		theStructs(f) = theStruct;
		f = f+1;
	end
end

% If there was no data in the file, return an empty matrix.
if ~exist('theStructs', 'var')
	theStructs = [];
end

% Close the file.
fclose(fid);