MATLAB Answers

How do I specify the compression level to gzip?

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sunil anandatheertha
sunil anandatheertha on 19 Jul 2011
Commented: raym on 19 Apr 2018
Is there a way I can specify the zip compression to "best compression" or "normal compression".

Answers (3)

Jan
Jan on 19 Jul 2011
This is the core method:
function zipLevel(ZIPFile, FileList, Level)
import java.io.*
import java.util.zip.*
import com.mathworks.mlwidgets.io.InterruptibleStreamCopier.*
if nargin < 3, Level = 6; end
% Create output stream and set the level of compression:
try
fileOut = FileOutputStream(ZIPFile);
catch
error(['*** ', mfilename, ': Cannot open for output: ', ...
char(10), ' ', ZIPFile]);
end
zipOut = ZipOutputStream(fileOut);
zipOut.setLevel(Level);
% This InterruptibleStreamCopier is unsupported and
% may change without notice.
StreamCopier = getInterruptibleStreamCopier;
% Append files to zip file:
FileList = cellstr(FileList);
for iFile = 1:numel(FileList)
aFile = FileList{iFile};
fileIn = FileInputStream(aFile);
zipObj = ZipEntry(aFile);
zipOut.putNextEntry(zipObj);
StreamCopier.copyStream(fileIn, zipOut);
fileIn.close;
zipOut.closeEntry;
end
zipOut.close;
fileOut.close;
This should be expanded by checking the the existence of file, getting the contents of folders and using a root folder for relative file names. Comments and file times can also be included by this method.
  1 Comment
raym
raym on 19 Apr 2018
Hi, I run your code and found that the filelist not compressed into the ZIPFile. instead, when I double click the zip file, it directly opens the D drive, and all the hard drive was indexed from here. But the file size is only 140kb.

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the cyclist
the cyclist on 19 Jul 2011
I don't know how to do this, but if you type
>> edit zip
you will get a bit more into the innards of the creation of the Java ZipEntry object, so maybe that will help.

Friedrich
Friedrich on 19 Jul 2011
Hi,
sry no you can't. At least without modifying the MATLAB Java code.

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