add fallback zlib/glib support on Octave via file-based zip/unzip

Contents.m

@@ -34,6 +34,7 @@
 % match_bracket - [endpos, maxlevel] = match_bracket(str,startpos,brackets)
 % mergestruct - s=mergestruct(s1,s2)
 % nestbracket2dim - [dims, isndarray, maxlevel, count] = nestbracket2dim(str,brackets)
+% octavezz - output = octavezz(input, iscompress, zipmethod)
 % savebj - bjd=savebj(obj)
 % savejd - savejd(rootname, obj, outputfile)
 % savejson - json=savejson(obj)

INDEX

@@ -37,6 +37,7 @@ Compression and Decompression
  lzmaencode
  zlibdecode
  zlibencode
+ octavezz
 Helper Functions
  decodevarname
  encodevarname

gzipdecode.m

@@ -44,7 +44,9 @@
  end
  return;
 elseif(isoctavemesh)
- error('You must install the ZMat toolbox (http:/NeuroJSON/zmat) to use this function in Octave');
+ warning('You are recommended to install the ZMat toolbox (http:/NeuroJSON/zmat) to use this function in Octave');
+ [varargout{1:nargout}]=octavezz(varargin{1}, 0, 'gzip');
+ return;
 end
 error(javachk('jvm'));
 

gzipencode.m

@@ -40,7 +40,9 @@
  [varargout{1:nargout}]=zmat(varargin{1},1,'gzip');
  return;
 elseif(isoctavemesh)
- error('You must install the ZMat toolbox (http:/NeuroJSON/zmat) to use this function in Octave');
+ warning('You are recommended to install the ZMat toolbox (http:/NeuroJSON/zmat) to use this function in Octave');
+ [varargout{1:nargout}]=octavezz(varargin{1}, 1, 'gzip');
+ return;
 end
 
 error(javachk('jvm'));

octavezz.m

@@ -0,0 +1,134 @@
+function varargout=octavezz(data, iscompress, zipmethod)
+%
+% output = octavezz(input, iscompress, zipmethod)
+% or
+% [output, info] = octavezz(input, iscompress, zipmethod)
+% unzipdata = octavezz(zipdata, info)
+%
+% Compress or decompress zlib and gzip memory buffers using zip/unzip/gzip/gunzip on Octave
+% in case ZMat toolbox (http:/NeuroJSON/zmat) was not installed (ZMat will be much faster)
+%
+% Copyright (c) 2023, Qianqian Fang (q.fang <at> neu.edu)
+%
+% input:
+% input: the input data (can be either compressed or before compression),
+% can be a string, a numerical vector or array
+% iscompress: (optional) if iscompress is 1, zmat compresses/encodes the input,
+% if 0, it decompresses/decodes the input. Default value is 1.
+%
+% if iscompress is set to a negative integer, (-iscompress) specifies
+% the compression level. For zlib/gzip, default level is 6 (1-9); for
+% lzma/lzip, default level is 5 (1-9); for lz4hc, default level is 8 (1-16).
+% the default compression level is used if iscompress is set to 1.
+%
+% zmat removes the trailing newline when iscompress=2 and method='base64'
+% all newlines are kept when iscompress=3 and method='base64'
+%
+% if one defines iscompress as the info struct (2nd output of zmat), zmat
+% will perform a decoding/decompression operation and recover the original
+% input using the info stored in the info structure.
+% method: (optional) compression method, only the below two methods are supported
+% 'zlib': zlib/zip based data compression (default)
+% 'gzip': gzip formatted data compression
+%
+% 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
+% info: (optional) a struct storing additional info regarding the input data, may have
+% 'type': the class of the input array
+% 'size': the dimensions of the input array
+% 'byte': the number of bytes per element in the input array
+% 'method': a copy of the 3rd input indicating the encoding method
+% 'status': the zlib/lzma/lz4 compression/decompression function return value,
+% including potential error codes; see documentation of the respective
+% libraries for details
+% 'level': a copy of the iscompress flag; if non-zero, specifying compression
+% level, see above
+%
+% examples:
+% [ss,info]=octavezz(ones(10))
+% orig=octavezz(ss,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 < 1)
+ fprintf(1,'Format: output = octavezz(data, iscompress, zipmethod)\n');
+ return;
+end
+
+if(nargin < 2)
+ iscompress=1;
+end
+
+if(nargin < 3)
+ zipmethod='zlib';
+end
+
+if(isstruct(iscompress))
+ inputinfo = iscompress;
+ iscompress = 0;
+end
+
+fname=tempname;
+tmpfile=fname;
+outputfile=fname;
+
+suff=struct('zlib', '.zip', 'gzip', '.gz');
+
+if(~isfield(suff,zipmethod))
+ error('zipmethod is not supported')
+end
+
+if(~iscompress)
+ tmpfile=[fname suff.(zipmethod)];
+end
+
+fd=fopen(tmpfile,'wb');
+if(~fd)
+ error('unable to create temporary file');
+end
+fwrite(fd, data, 'uint8');
+fclose(fd);
+
+if(iscompress)
+ outputfile=[fname suff.(zipmethod)];
+end
+
+if(~iscompress)
+ if(strcmp(zipmethod, 'zlib'))
+ outputfile=unzip(tmpfile, tempdir);
+ outputfile=[tempdir filesep outputfile{1}];
+ elseif(strcmp(zipmethod, 'gzip'))
+ gunzip(tmpfile);
+ end
+else
+ if(strcmp(zipmethod, 'zlib'))
+ zip(outputfile, tmpfile);
+ elseif(strcmp(zipmethod, 'gzip'))
+ gzip(tmpfile);
+ end
+end
+
+fd=fopen(outputfile, 'rb');
+if(~fd)
+ error('failed to unzip buffer');
+end
+varargout{1}=fread(fd, [1 inf], 'uint8');
+fclose(fd);
+
+if(nargout>1)
+ varargout{2}=struct('type',class(data),'size',size(data),'method',zipmethod,'status',0, 'level', iscompress);
+end
+
+if (exist('inputinfo', 'var') && isfield(inputinfo, 'type'))
+ if(strcmp(inputinfo.type,'logical'))
+ varargout{1} = logical(varargout{1});
+ else
+ varargout{1} = typecast(varargout{1}, inputinfo.type);
+ end
+ varargout{1} = reshape(varargout{1}, inputinfo.size);
+end

zlibdecode.m

@@ -45,7 +45,9 @@
  end
  return;
 elseif(isoctavemesh)
- error('You must install the ZMat toolbox (http:/NeuroJSON/zmat) to use this function in Octave');
+ warning('You are recommended to install the ZMat toolbox (http:/NeuroJSON/zmat) to use this function in Octave');
+ [varargout{1:nargout}]=octavezz(varargin{1}, 0, 'zlib');
+ return;
 end
 error(javachk('jvm'));
 

zlibencode.m

@@ -39,7 +39,9 @@
  [varargout{1:nargout}]=zmat(varargin{1},1,'zlib');
  return;
 elseif(isoctavemesh)
- error('You must install the ZMat toolbox (http:/NeuroJSON/zmat) to use this function in Octave');
+ warning('You are recommended to install the ZMat toolbox (http:/NeuroJSON/zmat) to use this function in Octave');
+ [varargout{1:nargout}]=octavezz(varargin{1}, 1, 'zlib');
+ return;
 end
 
 error(javachk('jvm'));