1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36

use crate::encoding::delta_length_byte_array;

use super::super::delta_bitpacked;

/// Encodes an iterator of according to DELTA_BYTE_ARRAY
pub fn encode<'a, I: Iterator<Item = &'a [u8]> + Clone>(iterator: I, buffer: &mut Vec<u8>) {
    let mut previous = b"".as_ref();

    let mut sum_lengths = 0;
    let prefixes = iterator
        .clone()
        .map(|item| {
            let prefix_length = item
                .iter()
                .zip(previous.iter())
                .enumerate()
                // find first difference
                .find_map(|(length, (lhs, rhs))| {
                    println!("{lhs} {rhs}");
                    (lhs != rhs).then(|| length)
                })
                .unwrap_or(previous.len());
            previous = item;

            sum_lengths += item.len() - prefix_length;
            prefix_length as i64
        })
        .collect::<Vec<_>>();
    delta_bitpacked::encode(prefixes.iter().copied(), buffer);

    let remaining = iterator
        .zip(prefixes)
        .map(|(item, prefix)| &item[prefix as usize..]);

    delta_length_byte_array::encode(remaining, buffer);
}