cosmo make temp filename skl

function filename = cosmo_make_temp_filename(prefix, suffix)
    % give temporary filename that does not exist when this function is called
    %
    % filename=cosmo_make_temp_filename(prefix,suffix)
    %
    % Inputs:
    %   prefix              optional, string with prefix for temporary file
    %                       (default: '')
    %   suffix              string [or cellstring] with suffix [suffixes] for
    %                       temporary file [files]
    %                       (default: '')
    %
    % Output:
    %   filename            filename that does not exist when this function was
    %                       called (in the current directory), starting with
    %                       prefix, ending with suffix, and with a random infix
    %                       string.
    %                       If suffix is a cellstring, then filename is a
    %                       cellstring with as many elements as suffix,
    %                       each with the same prefix and random infix.
    %
    % Examples:
    %   % generate random filename
    %   fn=cosmo_make_temp_filename();
    %
    %   % generate random filename starting with 'foo'
    %   fn=cosmo_make_temp_filename('foo');
    %
    %   % generate random filename starting with 'foo' and ending with '.bar'
    %   fn=cosmo_make_temp_filename('foo','.bar');
    %
    %   % generate two random filename, both starting with 'foo', and ending
    %   % with '.bar' and '.baz', respectively. The output fns is a cell with
    %   % two strings
    %   fns=cosmo_make_temp_filename('foo',{'.bar','.bar'});
    %
    % #   For CoSMoMVPA's copyright information and license terms,   #
    % #   see the COPYING file distributed with CoSMoMVPA.           #

    if nargin < 2
        suffix = '';
    end
    if nargin < 1
        prefix = '';
    end

    check_input(prefix, suffix);

    suffix_is_cell = iscell(suffix);

    if suffix_is_cell
        suffix_cell = suffix;
    else
        suffix_cell = {suffix};
    end

    nsuffix = numel(suffix_cell);

    filename_cell = cell(nsuffix, 1);
    while true
        infix = generate_random_infix();

        does_exist = false;

        for k = 1:nsuffix
            fn = [prefix infix suffix_cell{k}];

            if exist(fn, 'file')
                does_exist = true;
                break
            end

            filename_cell{k} = fn;
        end

        if ~does_exist
            break
        end
    end

    if suffix_is_cell
        filename = filename_cell;
    else
        filename = filename_cell{1};
    end

function infix = generate_random_infix(infix_length)
    if nargin < 1
        infix_length = 20;
    end

    char_val_min = double('a');
    char_val_max = double('z');
    char_val_range = char_val_max - char_val_min;

    rand_chars = char(rand(1, infix_length) * char_val_range + char_val_min);
    infix = ['tmp_' rand_chars];

function check_input(prefix, suffix)
    if ~ischar(prefix)
        error('prefix must be a string');
    end

    if ~ischar(suffix) && ~iscellstr(suffix)
        error('suffix must be string or cell with strings');
    end