generated from PlexSheep/baserepo
60 lines
1.9 KiB
Rust
60 lines
1.9 KiB
Rust
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//* # See what's behind the datatypes of Rust
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//*
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//* This Crate shows off how datatypes of rust are stored in memory.
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use std::any::{TypeId, type_name};
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/// ## Investigate the internal representation of variables
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///
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/// Takes 1. the Type and 2. a [`Vec`] of items (of that datatype).
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#[macro_export]
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macro_rules! investigate_memory_layout {
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($t:ty, $v:tt) => {
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println!("Type:\t{}", type_name::<$t>());
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println!("\talign:\t{:?} B", std::mem::align_of::<$t>());
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println!("\tID:\t{:?}\n", TypeId::of::<$t>());
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println!("\tItems:");
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unsafe {
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for (index, item) in $v.iter().enumerate() {
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let pointer = item as *const $t;
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let mut memory: [u8; std::mem::size_of::<$t>()] = std::mem::transmute(item.clone());
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memory.reverse();
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println!("\
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\t{index:02x}\titem:\t\t{item:?}\n\
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\t\tpointer: \t{:X?}\n\
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\t\talign: \t{}\n\
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\t\tsize: \t{}\n\
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\t\tmemory: \t{:X?}\n\
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\t\tbin mem: \t{}\n\
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\t\tnote: \tmemory order reversed\n\
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",
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pointer,
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byte_bit_display(std::mem::align_of_val(item)),
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byte_bit_display(memory.len()),
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memory,
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bytes_to_bin(&memory),
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);
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}
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}
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};
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}
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fn bytes_to_bin(v: &[u8]) -> String {
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if v.len() > 8 || v.len() < 1 {
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return String::from("(impractical size for dump)")
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}
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let mut s = format!("0b{:08b}", v.first().unwrap());
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for i in 1..v.len() {
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s.push_str(&format!("_{:08b}", v[i]));
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if i % 8 == 0 {
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s.push_str("\n")
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}
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}
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return s;
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}
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fn byte_bit_display(v: usize) -> String
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{
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format!("{:07} B = {:08} bit", v.clone(), v * 8)
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}
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