Compression Routines

version (7.77 KB) by Jesse Hopkins
Compress Matlab variables in the workspace. (supports cells, structs, matrices, strings, objects)


Updated 26 Jul 2010

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This Matlab class contains only static methods.
These methods will compress matlab variables using java GZIP functions.
Matrices, strings, structures, and cell arrays are supported. Matlab
objects are also supported provided they implement a "toByteArray" method
and a constructor of the form:
obj = constructor(byteArray,'PackedBytes')

x = % some matlab variable,
% can be a struct, cell-array,
% matrix, or object (if object conforms to certain standards)

cx = CompressLib.compress(x); % cx is a byte-array which contains
% compressed version of x

x2 = CompressLib.decompress(cx); %x2 is now a copy of x

The methods CompressLib.packBytes and CompressLib.unpackBytes are also
available. These methods may be used to make Matlab classes compliant
for the compression routines. See "packableObject.m" for an example
Matlab class which is compliant with CompressLib.

Use CompressLib.test to run a series of tests for functionality of this

These methods run pretty fast on numeric variables, however slow down more on structures, cell-arrays and objects. The biggest bottleneck is "typecast.m". You can vastly improve the performance by replacing these calls to typecast.m with the mex counterpart typecastc.mexw32, located in "matlabroot\toolbox\matlab\datatypes\private". Since it is in a private directory, you would have to make a copy of it somewhere else on your path in order for it to be visible publicly. (I noticed a ~37% improvement when running the test suite (CompressLib.test) by doing this.)

Cite As

Jesse Hopkins (2022). Compression Routines (, MATLAB Central File Exchange. Retrieved .

MATLAB Release Compatibility
Created with R2008b
Compatible with any release
Platform Compatibility
Windows macOS Linux

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