Android apps using directly or indirectly OpenGL cache compiled shaders into com.android.opengl.shaders_cache file.
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.
All parsing code for Ruby generated by Kaitai Struct depends on the Ruby runtime library. You have to install it before you can parse data.
The Ruby runtime library can be installed from RubyGems:
gem install kaitai-structParse a local file and get structure in memory:
data = AndroidOpenglShadersCache.from_file("path/to/local/file.bin")
Or parse structure from a string of bytes:
bytes = "\x00\x01\x02..."
data = AndroidOpenglShadersCache.new(Kaitai::Struct::Stream.new(bytes))
After that, one can get various attributes from the structure by invoking getter methods like:
data.crc32 # => crc32 of `contents`
# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
require 'kaitai/struct/struct'
unless Gem::Version.new(Kaitai::Struct::VERSION) >= Gem::Version.new('0.9')
raise "Incompatible Kaitai Struct Ruby API: 0.9 or later is required, but you have #{Kaitai::Struct::VERSION}"
end
##
# Android apps using directly or indirectly OpenGL cache compiled shaders
# into com.android.opengl.shaders_cache file.
# @see https://android.googlesource.com/platform/frameworks/native/+/master/opengl/libs/EGL/FileBlobCache.cpp Source
class AndroidOpenglShadersCache < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@magic = @_io.read_bytes(4)
raise Kaitai::Struct::ValidationNotEqualError.new([69, 71, 76, 36].pack('C*'), magic, _io, "/seq/0") if not magic == [69, 71, 76, 36].pack('C*')
@crc32 = @_io.read_u4le
@_raw_contents = @_io.read_bytes_full
_io__raw_contents = Kaitai::Struct::Stream.new(@_raw_contents)
@contents = Cache.new(_io__raw_contents, self, @_root)
self
end
class Alignment < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@alignment = @_io.read_bytes(((_io.pos + 3) & (~3 - _io.pos)))
self
end
##
# garbage from memory
attr_reader :alignment
end
class PrefixedString < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@len_str = @_io.read_u4le
@str = (Kaitai::Struct::Stream::bytes_terminate(@_io.read_bytes(len_str), 0, false)).force_encoding("ascii")
@alignment = Alignment.new(@_io, self, @_root)
self
end
attr_reader :len_str
attr_reader :str
attr_reader :alignment
end
##
# @see https://android.googlesource.com/platform/frameworks/native/+/master/opengl/libs/EGL/BlobCache.cpp Source
class Cache < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@magic = @_io.read_bytes(4)
raise Kaitai::Struct::ValidationNotEqualError.new([36, 98, 66, 95].pack('C*'), magic, _io, "/types/cache/seq/0") if not magic == [36, 98, 66, 95].pack('C*')
@version = @_io.read_u4le
@device_version = @_io.read_u4le
@num_entries = @_io.read_u4le
if version >= 3
@build_id = PrefixedString.new(@_io, self, @_root)
end
@entries = []
(num_entries).times { |i|
@entries << Entry.new(@_io, self, @_root)
}
self
end
class Entry < Kaitai::Struct::Struct
def initialize(_io, _parent = nil, _root = self)
super(_io, _parent, _root)
_read
end
def _read
@len_key = @_io.read_u4le
@len_value = @_io.read_u4le
@key = @_io.read_bytes(len_key)
@value = @_io.read_bytes(len_value)
@alignment = Alignment.new(@_io, self, @_root)
self
end
attr_reader :len_key
attr_reader :len_value
attr_reader :key
attr_reader :value
attr_reader :alignment
end
attr_reader :magic
attr_reader :version
attr_reader :device_version
attr_reader :num_entries
attr_reader :build_id
attr_reader :entries
end
attr_reader :magic
##
# crc32 of `contents`
attr_reader :crc32
attr_reader :contents
attr_reader :_raw_contents
end