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use std::{
    io::{Cursor, Seek, SeekFrom},
    ops::RangeBounds,
};

/// Tries to get a UTF-8 string from the given buffer at the provided range.
fn str_from_utf8_range(buf: &[u8], range: impl RangeBounds<usize>) -> Option<&str> {
    buf.get((range.start_bound().cloned(), range.end_bound().cloned()))
        .map(|slice| std::str::from_utf8(slice).expect("valid utf8"))
}

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Basics of RISC-V

• Notes.
  • See An Introduction to Assembly Programming with RISC-V.
  • ISA (Industry Standard Architecture) is the portion of the architecture which is visible to compiler writers. I.e., a contract.
  • There are 33 general-purpose unprivileged registers:
    • zero
    • t0 ~ t6 for temporary values, which are not to be persisted across calls.
    • s0 ~ s11 for saved values.
• a0 ~ a7 for arguments and return values.

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use std::collections::BTreeMap;

fn group<'a>(data: impl Iterator<Item = (&'a str, u32)>) -> BTreeMap<&'a str, u32> {
    data.fold(BTreeMap::new(), |mut map, (date, amount)| {
        *map.entry(date).or_default() += amount;
        map
    })
}

#[test]

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function query(label) {
  console.log(`(${label}) created 'lazy promise', but not started yet`);
  return {
    then(r) {
      console.log(`(${label}) started!`);
      // ... process query
      // "return" them:
      r([{ data: `result for ${label}` }]);
    },
  };

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macro_rules! cat {
    ($($str:expr),*) => {{
        const LEN: usize = $($str.len() + )* 0;
        to_str(&combine::<LEN>(&[$($str),*]))
    }};
}

const fn combine<const LEN: usize>(list: &[&'static str]) -> [u8; LEN] {
    let mut bytes = [0; LEN];
    let mut i = 0;

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use std::io;
use std::time::Duration;
use std::{
    io::Write,
    net::{SocketAddr, ToSocketAddrs, UdpSocket},
    str::FromStr,
};
use stun_rs::{
    MessageClass, MessageDecoderBuilder, MessageEncoderBuilder, StunMessageBuilder,
    attributes::stun::XorMappedAddress, methods::BINDING,