Shared via Rust Playground

playground.rs

fn old() -> Vec<u8> {
    let mut hash = vec![0u8; 8]; // vec of u8 representing the bits and bytes of the hash computed for the image.
    let raw: Vec<_> = (0 .. 72).rev().collect(); // vec of u8 representing gray pixels of an 9x8 image.
    

    for x in 0..8 {
        for y in 0..8 {
            if raw[x*8+y] > raw[x*8+y+1] {
                hash[x] |= 0x1 << y
            }
        }
    }
    
    hash
}

fn new() -> Vec<u8> {
    let mut hash = vec![0u8; 8]; // vec of u8 representing the bits and bytes of the hash computed for the image.
    let raw: Vec<_> = (0 .. 72).rev().collect(); // vec of u8 representing gray pixels of an 9x8 image.

    for (x, chunk) in raw.chunks(9).enumerate() {
        chunk[1..].iter().enumerate().fold(chunk[0], |before, (y, &current)| -> u8 {
            if before > current {
                hash[x] |= 0x1 << y;
            }
            current
        });
    }
    
    hash    
}

fn main(){
    println!("old: {:?}", old());
    println!("new: {:?}", new());

}