% linear cross fade the first segment with the second segment given a certain amount of overlap
% |----------seg1----------|
%			   |---------------seg2-----------------------|
%              |--overlap-|

function op = linear_cross_fade(seg_1, seg_2, overlap_length, cross_fade_duration)

    error(nargchk(3,4,nargin));
    if nargin < 4
        cross_fade_duration = overlap_length;
    end
    if cross_fade_duration > overlap_length
        cross_fade_duration = overlap_length;
    end
	% overlap the end of seg_1 with the start of seg_2 using a linear cross-fade
	if (length(seg_1) < overlap_length),
        seg_2 = seg_2(overlap_length - length(seg_1) + 1: length(seg_2));
		overlap_length = length(seg_1);
	end; % end of if statement

	if (length(seg_2) < overlap_length),
        seg_1 = seg_1(length(seg_1) - (overlap_length - overlap_length): length(seg_1));
		overlap_length = length(seg_2);
	end; % end of if statement

    
	overlapping_region = zeros(1, cross_fade_duration); % initialize the overlapping region
    seg_1 = seg_1(1: length(seg_1) - (overlap_length - cross_fade_duration));
    
	op = zeros(1, length(seg_1) + length(seg_2) - cross_fade_duration);

	if(overlap_length ~= 1)
		linear_ramp1 = (cross_fade_duration-1:-1:0) ./(cross_fade_duration-1);
		linear_ramp2 = (0:1:cross_fade_duration-1) ./(cross_fade_duration-1);
		overlapping_region = (seg_1(length(seg_1)-cross_fade_duration+1:length(seg_1)).*linear_ramp1) + (seg_2(1: cross_fade_duration).*linear_ramp2);
	end;
	op = [seg_1(1:length(seg_1)-cross_fade_duration) ,overlapping_region , seg_2(cross_fade_duration+1:length(seg_2))];
% END of linear_cross_fade function