collect bytes from string - arrays

Question

This is decoded string from bytes, they are always different. Am not using it in the code, its just for shown what is all about.
"Random String; Tags:Value1:1,Value:2,Value3:value4"
This is array of bytes from above string which i get as input.
[&u8...&u8]
What i need is get the values fromthose. While every byte in the array is changing. but some bytes are always same. I was thinking if there is any way how to extract it without using any Strings... Thanks for any ideas
so the output would look like this:
let v1 = [&u8, &u8, &u8, &u8, &u8];
let v2 = [&u8, &u8];
let v3 = [&u8];
let v4 = [&u8];
let v5 = [&u8];

Answer 1

You can do all this without allocating any extra space using rusts iterators, using split and related functions
At the top level, your data is of the form (key:value;)*
This suggests first splitting on ;
Then splitting each of these pieces into key and value using :
In your case, all the information is when the key is "tags".
Then within the tags section, you again have (mostly) key-value pairs of the form (key-value,)* so we need to split on , then break into key-value pairs using -.
An example that does this but only prints all the tag key-value pairs is:
fn split_kv(v: &[u8], c: u8) -> Option<(&[u8], &[u8])> {
let n = v.iter().position(|&b| b == c)?;
let w = v.split_at(n);
Some((w.0, &(w.1)[1..]))
}
fn main() {
let s: &str = "Background:Sunfire Topo;Base:Eagle;Accessory3:None;Patch:Oreo;Jacket:Pink Bonez;Eyes:BloodShot;Beak:Drool;Accessory2:Nose Ring;Accessory1:None;Item:Knife;tags:Dope Eagles,ELEMENT-HYDRO,ATTACK-10,DEFENSE-5,HIGHNESS-4,SWAG-1;metadata:QmU7JcFDoGcUvNkDgsPz9cy13md4xHdNyD6itwmgVLuo7x/860.json";
let ss: &[u8] = s.as_bytes();
let tags = ss
.split(|&b| b == b';') // Break up at ';'
.filter_map(|s| split_kv(s, b':')) // Split each piece into key-value pairs using ':'
.filter_map(|(k, v)| { // Only keep the tags entry.
if k == "tags".as_bytes() {
Some(v)
} else {
None
}
})
.next() // And just take the first of those.
.unwrap();
// Split the tags by ','
for t in tags.split(|&b| b == b',') {
// Then try to convert each to a key-value using '-' as seperator.
if let Some((k, v)) = split_kv(t, b'-') {
println!(
"k={:?} v={:?}",
std::str::from_utf8(k).unwrap(),
std::str::from_utf8(v).unwrap()
);
} else {
println!("t={:?}", std::str::from_utf8(t).unwrap());
}
}
}
You can run this here