com.android.opengl.shaders_cache file: Python parsing library

Android apps using directly or indirectly OpenGL cache compiled shaders into com.android.opengl.shaders_cache file.

Application

Android

KS implementation details

License: Apache-2.0

This page hosts a formal specification of com.android.opengl.shaders_cache file using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime library

All parsing code for Python generated by Kaitai Struct depends on the Python runtime library. You have to install it before you can parse data.

The Python runtime library can be installed from PyPI:

python3 -m pip install kaitaistruct

Code

Parse a local file and get structure in memory:

data = AndroidOpenglShadersCache.from_file("path/to/local/file.com.android.opengl.shaders_cache file")

Or parse structure from a bytes:

from kaitaistruct import KaitaiStream, BytesIO

raw = b"\x00\x01\x02..."
data = AndroidOpenglShadersCache(KaitaiStream(BytesIO(raw)))

After that, one can get various attributes from the structure by invoking getter methods like:

data.crc32 # => crc32 of `contents`

Python source code to parse com.android.opengl.shaders_cache file

android_opengl_shaders_cache.py

# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

from pkg_resources import parse_version
import kaitaistruct
from kaitaistruct import KaitaiStruct, KaitaiStream, BytesIO


if parse_version(kaitaistruct.__version__) < parse_version('0.9'):
    raise Exception("Incompatible Kaitai Struct Python API: 0.9 or later is required, but you have %s" % (kaitaistruct.__version__))

class AndroidOpenglShadersCache(KaitaiStruct):
    """Android apps using directly or indirectly OpenGL cache compiled shaders
    into com.android.opengl.shaders_cache file.
    
    .. seealso::
       Source - https://android.googlesource.com/platform/frameworks/native/+/master/opengl/libs/EGL/FileBlobCache.cpp
    """
    def __init__(self, _io, _parent=None, _root=None):
        self._io = _io
        self._parent = _parent
        self._root = _root if _root else self
        self._read()

    def _read(self):
        self.magic = self._io.read_bytes(4)
        if not self.magic == b"\x45\x47\x4C\x24":
            raise kaitaistruct.ValidationNotEqualError(b"\x45\x47\x4C\x24", self.magic, self._io, u"/seq/0")
        self.crc32 = self._io.read_u4le()
        self._raw_contents = self._io.read_bytes_full()
        _io__raw_contents = KaitaiStream(BytesIO(self._raw_contents))
        self.contents = AndroidOpenglShadersCache.Cache(_io__raw_contents, self, self._root)

    class Alignment(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            self._io = _io
            self._parent = _parent
            self._root = _root if _root else self
            self._read()

        def _read(self):
            self.alignment = self._io.read_bytes(((self._io.pos() + 3) & (~3 - self._io.pos())))


    class PrefixedString(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            self._io = _io
            self._parent = _parent
            self._root = _root if _root else self
            self._read()

        def _read(self):
            self.len_str = self._io.read_u4le()
            self.str = (KaitaiStream.bytes_terminate(self._io.read_bytes(self.len_str), 0, False)).decode(u"ascii")
            self.alignment = AndroidOpenglShadersCache.Alignment(self._io, self, self._root)


    class Cache(KaitaiStruct):
        """
        .. seealso::
           Source - https://android.googlesource.com/platform/frameworks/native/+/master/opengl/libs/EGL/BlobCache.cpp
        """
        def __init__(self, _io, _parent=None, _root=None):
            self._io = _io
            self._parent = _parent
            self._root = _root if _root else self
            self._read()

        def _read(self):
            self.magic = self._io.read_bytes(4)
            if not self.magic == b"\x24\x62\x42\x5F":
                raise kaitaistruct.ValidationNotEqualError(b"\x24\x62\x42\x5F", self.magic, self._io, u"/types/cache/seq/0")
            self.version = self._io.read_u4le()
            self.device_version = self._io.read_u4le()
            self.num_entries = self._io.read_u4le()
            if self.version >= 3:
                self.build_id = AndroidOpenglShadersCache.PrefixedString(self._io, self, self._root)

            self.entries = [None] * (self.num_entries)
            for i in range(self.num_entries):
                self.entries[i] = AndroidOpenglShadersCache.Cache.Entry(self._io, self, self._root)


        class Entry(KaitaiStruct):
            def __init__(self, _io, _parent=None, _root=None):
                self._io = _io
                self._parent = _parent
                self._root = _root if _root else self
                self._read()

            def _read(self):
                self.len_key = self._io.read_u4le()
                self.len_value = self._io.read_u4le()
                self.key = self._io.read_bytes(self.len_key)
                self.value = self._io.read_bytes(self.len_value)
                self.alignment = AndroidOpenglShadersCache.Alignment(self._io, self, self._root)