mildsunrise

def der_tag(tag_type: int, composed = False, tag_class = 0):
	assert 0 <= tag_class < 4 and 0 <= tag_type < 31  # FIXME: long tag types not implemented
	return bytes([ tag_class << 6 | int(composed) << 5 | tag_type ])
def der_length(x: int):
	if x < 128: return bytes([x])
	n = (x.bit_length() + 7) // 8
	assert n < 127
	return bytes([ 128 | n ]) + x.to_bytes(n)
def der_wrap(payload: bytes, raw: bool, tag_type: int, composed = False, tag_class = 0):
	if raw: return payload

mildsunrise

resources to find what Apple/Asahi acronyms mean:

• check out this table
• search with site:asahilinux.org (maybe they talked about it in the blog)
• grep the linux and m1n1 repos

some other random acronyms, mostly peripherals of the SoC:

• AIC → Apple Interrupt Controller
• AP → Application Processor (where the OS runs)
• DART → Device Address Resolution Table (IOMMU)

mildsunrise

#!/usr/bin/env python3
'''
Decompresses a pbzx stream.

Simplified/corrected version of <https://gist.github.com/Lekensteyn/6e0840e77bc9bd013f57>

Example usage (from Python):

  decompress_pbzx(open('PayloadJava', 'rb'), open('PayloadJava.cpio', wb'))

mildsunrise

[lz-string][] is a very popular library that compresses UTF-16 strings using a variation of the [LZ78][] algorithm where literals are only encoded once (and referred as dictionary indexes afterwards).

Despite its impressive 10 million downloads per week at the time of this writing, there is no official documentation on the wire format implemented by this library, and the horrible code quality makes it hard to understand from it. Furthermore, the code contains many bugs / gotchas, some of which are enumerated below. This is probably why many of the [numerous ports][ports] of the library blindly copy its code, doing little more

mildsunrise

import os, stat
from contextlib import contextmanager
from subprocess import run

@contextmanager
def fd_context(fd: int):
    try:
        yield fd
    finally:
        os.close(fd)

mildsunrise

open import Level using (suc; _⊔_)
open import Function using (id; _∘_)

open import Data.List as List using (
    List; []; _∷_; [_]; map; reverse; align; alignWith; foldr; head; last; drop; length
    )
import Data.List.Properties as List
import Data.List.Relation.Unary.All as All
import Data.List.Relation.Binary.Pointwise as PW

mildsunrise

JNIEnv

(keep in mind that JNI methods get a JNIEnv *, not a direct JNIEnv)

given JNIEnv x, you can write ((void**)x)[N] to access a function pointer, where N is:

     4	GetVersion
     5	DefineClass
 6	FindClass

mildsunrise

import java.awt.*;
import java.awt.datatransfer.*;
import java.awt.image.*;
import java.io.*;

public class Main {
	public static void main(String[] arg) {
		var flavorMap = (FlavorTable) SystemFlavorMap.getDefaultFlavorMap();
		System.out.println("formats for image flavor: ");
		for (var format : flavorMap.getNativesForFlavor(DataFlavor.imageFlavor))

mildsunrise

use std::{ops::{Add, AddAssign}, convert::TryInto};

/// In-place unstable radix sort with sentinel
///
/// - `L` is the type used for bin counts (must be able to hold `arr.len()`).
/// - `key: F` is a function taking an array item + a level, and returning an alphabet symbol.
/// - `AL` is the alphabet length, i.e. number of bins. it must hold that `key(...) < AL`.
///
/// 0 is the sentinel, meaning that for any item, `key(item, max_level) == 0`.
/// `max_level` may differ among items.

mildsunrise

'''
Reads the contents of a TCP stream carrying [one side of] an
RTMP connection, and blindly dumps streams above 0 in an FLV.

$ ./rtmp2flv.py < tcp-stream > video.flv
'''

from enum import IntEnum, unique
from dataclasses import dataclass, field
from typing import NamedTuple, Self, Optional