How to use this app? Read the manual to know more.
Notice! If you're running on Windows, you can try substituting gradlew with gradlew.bat. That might solve any potential issues.
This app never writes to the input file, but just in case, make backups of the important files you choose to work with. Or, alternatively, only use non-important files such as blurry pictures of your cat.
You can always get the latest version of this app from GitHub.
If you'd like a pre-built version, go here to download a JAR-file.
To clone this project (must have Git installed), issue this command:
git clone https://github.com/gotonode/compress.git
This will download the latest version (master branch) to a folder named compress.
It will also download the .git folder which includes the complete (commit) history of this project. Over time, it will only get bigger in size. If you would like to avoid this, you can download the ZIP-file from GitHub. See the top of this document for the link.
You need to have Java installed, preferably an up-to-date version.
Issue this command in the folder you have downloaded/cloned this project:
gradlew run
If you downloaded the JAR-file, use this command instead:
java -jar compress.jar
Where compress.jar is the name of the downloaded JAR-file. It might differ.
If you have downloaded/cloned this project, and wish to build it, issue this command:
gradlew build
Once you've downloaded/cloned this project, and successfully started it, you'll be greeted with a view similar to this:
Welcome to Compress (version N)!
You can find the latest version here: https://github.com/gotonode/compress/
Please choose a command from the following:
H: Compress a file using Huffman
L: Compress a file using LZW
D: Decompress a previously compressed file
B: Benchmark Huffman against LZW
X: Print these instructions again
E: Exit from the program
Command:
Here you can give a command from the list. Next, we'll go over these commands.
With this, you can compress a single file using Huffman coding. You'll need to enter that file's full path or name (current directory).
After that, you'll specify the name of the compressed file. Please do not use the same name for the input and output files, as that will not work.
Once the compression is done, the app tells you the size of the compressed file as well as how much time the compression process took.
If your compressed file turned out bigger than your original file, that means the overhead (additional data used for management) along with the source compression data have a combined byte size that surpasses the original. It most often happens with already-compressed files such as JPEG-files. The optimum strategy with such files is not to use compression (at least my Huffman and LZW implementations) at all.
Exactly as above with Huffman compression, except using LZW.
Please refer to that section.
Once you have a file that is compressed with either Huffman or LZW, you can use this command to decompress that file.
You'll need to specify the input file as well as the target file (where the file will be decompressed to). Please do not specify these as the same file. That will not work.
After the decompression operation, the app will inform you about the time it took and how much was the size difference.
Notice! Detection measures are in place to figure out if your input file is indeed a Huffman or LZW compressed file. But if these measures somehow fail, and the app starts to decompress a file that isn't properly compressed, the result could be a very big file or an out of memory / disk space error. In that case, simple remove the decompressed garbage file.
You can use this functionality to benchmark Huffman against LZW.
First, specify the input file that is used in the benchmarking process. No new files will be left as residue, as those are automatically removed.
After the benchmarking, the app prints the results for your convenience.
Here's a sample output from one benchmarking run on the README.md file (yours might look different, depending on app version):
We'll benchmark Huffman against LZW using your chosen file. No new files will be left as residue.
Consider choosing a file that is not already compressed, as compressed files do not compress very well.
Name of your source file (must already exist): README.md
Compression time results:
Huffman took 7 ms to compress
LZW took 59 ms to compress
Regarding compression time, the winner is Huffman!
Decompression time results:
Huffman took 10 ms to decompress
LZW took 4 ms to decompress
Regarding decompression time, the winner is LZW!
Compression size results (the original file was 3735 bytes):
Huffman compressed it to 2572 bytes (a 31,14 % reduction)
LZW compressed it to 2718 bytes (a 27,23 % reduction)
Regarding file size, the winner is Huffman!
In case you forget about the commands, you can ask for them again.
Simple as that.
Once you're done with the app, use this command to exit.
Alternatively, the [CTRL] + [Z] shortcut will work.
This app accepts any binary file as input. You can compress (and decompress), amongst other things, images, text documents, videos, music and even archives.
As output, you'll specify the name of the file you want to contain the compressed/decompressed data.
Notice! If your chosen output file exists, it will be overwritten without confirmation. The app will inform you about this.