gzipencode.m

function varargout = gzipencode(varargin)
%
% output = gzipencode(input)
%    or
% [output, info] = gzipencode(input)
%
% Compress a string or numerical array using the GZIP-compression
%
% This function depends on JVM in MATLAB or, can optionally use the ZMat 
% toolbox (http://github.com/fangq/zmat)
%
% Copyright (c) 2012, Kota Yamaguchi
% URL: https://www.mathworks.com/matlabcentral/fileexchange/39526-byte-encoding-utilities
%
% Modified by: Qianqian Fang (q.fang <at> neu.edu)
%
% input:
%      input: the original data, can be a string, a numerical vector or array
%
% output:
%      output: the decompressed byte stream stored in a uint8 vector; if info is 
%            given, output will restore the original data's type and dimensions
%
% examples:
%      [bytes, info]=gzipencode(eye(10));
%      orig=gzipdecode(bytes,info);
%
% license:
%     BSD or GPL version 3, see LICENSE_{BSD,GPLv3}.txt files for details 
%
% -- this function is part of JSONLab toolbox (http://iso2mesh.sf.net/cgi-bin/index.cgi?jsonlab)
%


if(nargin==0)
    error('you must provide at least 1 input');
end

if(exist('zmat','file')==2 || exist('zmat','file')==3)
    [varargout{1:nargout}]=zmat(varargin{1},1,'gzip');
    return;
elseif(isoctavemesh)
    error('You must install the ZMat toolbox (http://github.com/fangq/zmat) to use this function in Octave');
end

error(javachk('jvm'));

if(ischar(varargin{1}))
    varargin{1}=uint8(varargin{1});
end

input=typecast(varargin{1}(:)','uint8');

buffer = java.io.ByteArrayOutputStream();
gzip = java.util.zip.GZIPOutputStream(buffer);
gzip.write(input, 0, numel(input));
gzip.close();

varargout{1} = typecast(buffer.toByteArray(), 'uint8')';

if(nargout>1)
    varargout{2}=struct('type',class(varargin{1}),'size',size(varargin{1}),'method','gzip','status',0);
end