tvl-depot/tvix/derivation/src/nix_hash.rs
Jürgen Hahn 6f993b8bde feat(tvix/derivation): add nix drv path generation to Derivation
This adds a function to generate the derivation path. The computation
is based on the Go implementation.

Change-Id: Iae89db4976f5fd9208f0453f73688689a245cd66
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7729
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
2023-01-04 12:24:00 +00:00

15 lines
611 B
Rust

/// CompressHash takes an arbitrary long sequence of bytes (usually a hash
/// digest), and returns a sequence of bytes of length output_size.
/// It's calculated by rotating through the bytes in the output buffer (zero-
/// initialized), and XOR'ing with each byte of the passed input.
/// It consumes 1 byte at a time, and XOR's it with the current value in the
/// output buffer.
pub fn compress_hash(input: &[u8], output_size: usize) -> Vec<u8> {
let mut output: Vec<u8> = vec![0; output_size];
for (ii, ch) in input.iter().enumerate() {
output[ii % output_size] ^= ch;
}
output
}