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| - | ==== T03. [20p] Zip with compression levels ==== | ||
| - | The **zip** command is used for compression and file packaging under Linux/Unix operating system. It provides 10 levels of compression, where: | ||
| - | * **level 0** : provides no compression, only packaging | ||
| - | * **level 6** : used as default compression level | ||
| - | * **level 9** : provides maximum compression | ||
| - | |||
| - | <code bash> | ||
| - | $ zip -5 file.zip file.txt | ||
| - | </code> | ||
| - | |||
| - | === [15p] Task A - Measurements === | ||
| - | Write a script to measure the compression rate and the time required for each level. Use the following files: | ||
| - | * two largest bitmaps from [[https://www.fileformat.info/format/bmp/sample/index.htm|here]] | ||
| - | * this large text file [[https://norvig.com/big.txt|here]] | ||
| - | |||
| - | === [5p] Task B - Plot === | ||
| - | Fill the data you obtained into the python3 script in {{:ep:labs:plot.zip|plot.zip}}. \\ | ||
| - | Make sure you have **python3** and **python3-matplotlib** installed. | ||
| - | |||
| - | <solution -hidden> | ||
| - | **Task A:** | ||
| - | |||
| - | <code bash> | ||
| - | #!/bin/bash | ||
| - | |||
| - | # clean up base files directory and archives | ||
| - | rm -rf file* | ||
| - | mkdir files | ||
| - | |||
| - | # download some large files (2 images, 1 text) | ||
| - | ( cd files \ | ||
| - | ; printf "\033[33mStarting file download...\n\tPart 1/3 ... " \ | ||
| - | ; wget -q -O image_1.bmp https://www.fileformat.info/format/bmp/sample/4cb74cda027a43f3b278c05c3770950f/download \ | ||
| - | ; printf "\033[32mdone\n\t\033[33mPart 2/3 ... " \ | ||
| - | ; wget -q -O image_2.bmp https://www.fileformat.info/format/bmp/sample/1d71eff930af4773a836a32229fde106/download \ | ||
| - | ; printf "\033[32mdone\n\t\033[33mPart 3/3 ... " \ | ||
| - | ; wget -q -O text_file.txt https://norvig.com/big.txt \ | ||
| - | ; printf "\033[32mdone\n\033[0m" | ||
| - | ) | ||
| - | |||
| - | # archive folder | ||
| - | for i in $(seq 0 9); do | ||
| - | if [ ${i} -eq 6 ]; then | ||
| - | printf "\n\033[31m >>> Default compression level <<<" | ||
| - | fi | ||
| - | |||
| - | printf "\n\033[33mStarting: \033[1mzip -r -${i} files-${i}.zip files/\n\033[0m" | ||
| - | |||
| - | time zip -r -${i} files-$i.zip files | ||
| - | done | ||
| - | </code> | ||
| - | |||
| - | **Task B:** | ||
| - | <code python> | ||
| - | #!/usr/bin/python3 | ||
| - | |||
| - | import matplotlib.pyplot as plt | ||
| - | |||
| - | |||
| - | def main(): | ||
| - | # TODO: for each compression level in {0, 1, ..., 9}: | ||
| - | # fill real_time [ms] | ||
| - | # fill archive_size [bytes] | ||
| - | level = list(range(10)) | ||
| - | real_time = [ 47, 251, 278, 356, 350, 489, 688, 810, 1027, 1074 ] | ||
| - | archive_size = [ 12193688, 5762873, 5570296, 5401227, 5307842, | ||
| - | 5185863, 5130121, 5118616, 5111763, 5111482 ] | ||
| - | |||
| - | archive_size = [it / 1024 for it in archive_size] | ||
| - | |||
| - | # plot data | ||
| - | fix, axs = plt.subplots(2) | ||
| - | |||
| - | axs[0].plot(level, real_time, 'bo-') | ||
| - | axs[1].plot(level, archive_size, 'ro-') | ||
| - | |||
| - | axs[0].set_xticks(level) | ||
| - | axs[1].set_xticks(level) | ||
| - | |||
| - | axs[0].grid(True, which='both') | ||
| - | axs[1].grid(True, which='both') | ||
| - | |||
| - | axs[0].set_xlabel('Compression level') | ||
| - | axs[1].set_xlabel('Compression level') | ||
| - | |||
| - | axs[0].set_ylabel('Time [ms]') | ||
| - | axs[1].set_ylabel('Archive size [byte]') | ||
| - | |||
| - | plt.show() | ||
| - | |||
| - | |||
| - | if __name__ == '__main__': | ||
| - | main() | ||
| - | </code> | ||
| - | </solution> | ||
