Initial commit

.gitignore

@@ -0,0 +1,162 @@
+# 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/
+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/
+cover/
+
+# 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/
+
+# PyBuilder
+.pybuilder/
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+#   For a library or package, you might want to ignore these files since the code is
+#   intended to run in multiple environments; otherwise, check them in:
+# .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
+
+# poetry
+#   Similar to Pipfile.lock, it is generally recommended to include poetry.lock in version control.
+#   This is especially recommended for binary packages to ensure reproducibility, and is more
+#   commonly ignored for libraries.
+#   https://python-poetry.org/docs/basic-usage/#commit-your-poetrylock-file-to-version-control
+#poetry.lock
+
+# pdm
+#   Similar to Pipfile.lock, it is generally recommended to include pdm.lock in version control.
+#pdm.lock
+#   pdm stores project-wide configurations in .pdm.toml, but it is recommended to not include it
+#   in version control.
+#   https://pdm.fming.dev/latest/usage/project/#working-with-version-control
+.pdm.toml
+.pdm-python
+.pdm-build/
+
+# PEP 582; used by e.g. github.com/David-OConnor/pyflow and github.com/pdm-project/pdm
+__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/
+
+# Cython debug symbols
+cython_debug/
+
+# PyCharm
+#  JetBrains specific template is maintained in a separate JetBrains.gitignore that can
+#  be found at https://github.com/github/gitignore/blob/main/Global/JetBrains.gitignore
+#  and can be added to the global gitignore or merged into this file.  For a more nuclear
+#  option (not recommended) you can uncomment the following to ignore the entire idea folder.
+#.idea/

igelfs/__init__.py

@@ -0,0 +1,36 @@
+"""
+Python interface for the IGEL filesystem.
+
+For a standard IGEL OS disk image, the layout is similar to the below:
+- Partition 1
+  - IGEL FS
+- Partition 2
+  - FAT32, ESP #1
+- Partition 3
+  - FAT32, ESP #2
+
+IGEL FS has the following layout:
+- Section #0
+  - Boot Registry
+    - Boot Registry Entries
+  - Directory
+    - Partition Descriptors
+    - Fragment Descriptors
+- Section #1...
+  - Section Header
+  - Partition
+    - Partition Header
+    - Partition Payload
+"""
+
+from igelfs.filesystem import Filesystem, Section
+from igelfs.models import BootRegistryHeader, Directory, PartitionHeader, SectionHeader
+
+__all__ = [
+    "BootRegistryHeader",
+    "Directory",
+    "Filesystem",
+    "PartitionHeader",
+    "Section",
+    "SectionHeader",
+]

igelfs/base.py

@@ -0,0 +1,98 @@
+"""Abstract base classes for various data models."""
+
+import io
+from abc import ABC
+from dataclasses import dataclass, fields
+from typing import ClassVar, get_args, get_origin
+
+
+@dataclass
+class BaseDataModel(ABC):
+    """Abstract base class for data model."""
+
+    MODEL_ATTRIBUTE_SIZES: ClassVar[dict[str, int]]
+
+    def __len__(self) -> int:
+        """Implement __len__ data model method."""
+        return self.size
+
+    def to_bytes(self) -> bytes:
+        """Return bytes of all data."""
+        with io.BytesIO() as fd:
+            for attribute, size in self.MODEL_ATTRIBUTE_SIZES.items():
+                data = getattr(self, attribute)
+                match data:
+                    case bytes():
+                        fd.write(data)
+                    case int():
+                        fd.write(data.to_bytes(size))
+                    case str():
+                        fd.write(data.encode())
+                    case BaseDataModel() | DataModelCollection():
+                        fd.write(data.to_bytes())
+            fd.seek(0)
+            return fd.read()
+
+    @property
+    def size(self) -> int:
+        """Return actual size of all data."""
+        return len(self.to_bytes())
+
+    @classmethod
+    def get_model_size(cls) -> int:
+        """Return expected total size of data for model."""
+        return sum(cls.MODEL_ATTRIBUTE_SIZES.values())
+
+    def verify(self) -> bool:
+        """Verify data model integrity."""
+        return self.size == self.get_model_size()
+
+    @classmethod
+    def from_bytes_to_dict(cls, data: bytes) -> dict[str, bytes]:
+        """Return dictionary from bytes."""
+        model = {}
+        with io.BytesIO(data) as fd:
+            for attribute, size in cls.MODEL_ATTRIBUTE_SIZES.items():
+                model[attribute] = fd.read(size)
+        return model
+
+    @classmethod
+    def from_bytes(cls, data: bytes) -> "BaseDataModel":
+        """Return data model instance from bytes."""
+        model = cls.from_bytes_to_dict(data)
+        for field in fields(cls):
+            if get_origin(field.type) == DataModelCollection:
+                inner = get_args(field.type)[0]
+                model[field.name] = DataModelCollection(
+                    inner.from_bytes(chunk)
+                    for chunk in [
+                        model[field.name][i : i + inner.get_model_size()]
+                        for i in range(
+                            0, len(model[field.name]), inner.get_model_size()
+                        )
+                    ]
+                )
+            elif field.type == str:
+                model[field.name] = model[field.name].decode()
+            elif field.type == int:
+                model[field.name] = int.from_bytes(model[field.name])
+            else:
+                model[field.name] = field.type(model[field.name])
+        return cls(**model)
+
+
+class DataModelCollection(list):
+    """List subclass to provide additional helper methods."""
+
+    def to_bytes(self) -> bytes:
+        """Return bytes of all models."""
+        with io.BytesIO() as fd:
+            for model in self:
+                fd.write(model.to_bytes())
+            fd.seek(0)
+            return fd.read()
+
+    @property
+    def size(self) -> int:
+        """Return actual size of all data."""
+        return len(self.to_bytes())