Supplement materials for the bitwise operators article

Author: bzaczynski

bitwise-operators/.gitignore

@@ -0,0 +1,288 @@
+# Created by https://www.toptal.com/developers/gitignore/api/python,pycharm,visualstudiocode,sublimetext
+# Edit at https://www.toptal.com/developers/gitignore?templates=python,pycharm,visualstudiocode,sublimetext
+
+### PyCharm ###
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio, WebStorm and Rider
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# Generated files
+.idea/**/contentModel.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn.  Uncomment if using
+# auto-import.
+# .idea/artifacts
+# .idea/compiler.xml
+# .idea/jarRepositories.xml
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+# *.iml
+# *.ipr
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# Android studio 3.1+ serialized cache file
+.idea/caches/build_file_checksums.ser
+
+### PyCharm Patch ###
+# Comment Reason: https://github.com/joeblau/gitignore.io/issues/186#issuecomment-215987721
+
+# *.iml
+# modules.xml
+# .idea/misc.xml
+# *.ipr
+
+# Sonarlint plugin
+# https://plugins.jetbrains.com/plugin/7973-sonarlint
+.idea/**/sonarlint/
+
+# SonarQube Plugin
+# https://plugins.jetbrains.com/plugin/7238-sonarqube-community-plugin
+.idea/**/sonarIssues.xml
+
+# Markdown Navigator plugin
+# https://plugins.jetbrains.com/plugin/7896-markdown-navigator-enhanced
+.idea/**/markdown-navigator.xml
+.idea/**/markdown-navigator-enh.xml
+.idea/**/markdown-navigator/
+
+# Cache file creation bug
+# See https://youtrack.jetbrains.com/issue/JBR-2257
+.idea/$CACHE_FILE$
+
+# CodeStream plugin
+# https://plugins.jetbrains.com/plugin/12206-codestream
+.idea/codestream.xml
+
+### Python ###
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+pip-wheel-metadata/
+share/python-wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+*.py,cover
+.hypothesis/
+.pytest_cache/
+pytestdebug.log
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+db.sqlite3-journal
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+doc/_build/
+
+# PyBuilder
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+.python-version
+
+# pipenv
+#   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
+#   However, in case of collaboration, if having platform-specific dependencies or dependencies
+#   having no cross-platform support, pipenv may install dependencies that don't work, or not
+#   install all needed dependencies.
+#Pipfile.lock
+
+# PEP 582; used by e.g. github.com/David-OConnor/pyflow
+__pypackages__/
+
+# Celery stuff
+celerybeat-schedule
+celerybeat.pid
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/
+
+# pytype static type analyzer
+.pytype/
+
+### SublimeText ###
+# Cache files for Sublime Text
+*.tmlanguage.cache
+*.tmPreferences.cache
+*.stTheme.cache
+
+# Workspace files are user-specific
+*.sublime-workspace
+
+# Project files should be checked into the repository, unless a significant
+# proportion of contributors will probably not be using Sublime Text
+# *.sublime-project
+
+# SFTP configuration file
+sftp-config.json
+
+# Package control specific files
+Package Control.last-run
+Package Control.ca-list
+Package Control.ca-bundle
+Package Control.system-ca-bundle
+Package Control.cache/
+Package Control.ca-certs/
+Package Control.merged-ca-bundle
+Package Control.user-ca-bundle
+oscrypto-ca-bundle.crt
+bh_unicode_properties.cache
+
+# Sublime-github package stores a github token in this file
+# https://packagecontrol.io/packages/sublime-github
+GitHub.sublime-settings
+
+### VisualStudioCode ###
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+*.code-workspace
+
+### VisualStudioCode Patch ###
+# Ignore all local history of files
+.history
+
+# End of https://www.toptal.com/developers/gitignore/api/python,pycharm,visualstudiocode,sublimetext

bitwise-operators/README.md

@@ -0,0 +1,22 @@
+# Bitwise Operators in Python
+
+Source code of the least-significant bit **steganography** example from the [Bitwise Operators in Python](https://realpython.com/python-bitwise-operators/) article.  
+
+## Installation
+
+There are no external dependencies except for a Python interpreter.
+
+## Running
+
+Change directory to the current folder, where this `README.md` file is located, and then execute Python module:
+
+```shell
+$ python -m stegano /path/to/bitmap (--encode /path/to/file | --decode | --erase)
+```
+
+For example, to extract a secret file from the attached bitmap, type the following:
+
+```shell
+$ python -m stegano example.bmp -d
+Extracted a secret file: podcast.mp4
+```

bitwise-operators/example.bmp

@@ -0,0 +1,28 @@
+"""
+Runnable module, can be executed as:
+$ python -m stegano
+"""
+
+from .bitmap import Bitmap
+from .cli import CommandLineArguments, parse_args
+from .decoder import decode
+from .encoder import encode
+from .eraser import erase
+
+
+def main(args: CommandLineArguments) -> None:
+    """Entry point to the script."""
+    with Bitmap(args.bitmap) as bitmap:
+        if args.encode:
+            encode(bitmap, args.encode)
+        elif args.decode:
+            decode(bitmap)
+        elif args.erase:
+            erase(bitmap)
+
+
+if __name__ == "__main__":
+    try:
+        main(parse_args())
+    except Exception as ex:  # pylint: disable=W0703
+        print(ex)