From 6f993b8bde8201213fe2953ea663ac387de916e3 Mon Sep 17 00:00:00 2001 From: Jürgen Hahn Date: Mon, 2 Jan 2023 16:09:18 +0100 Subject: 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 --- tvix/derivation/src/nix_hash.rs | 15 +++++++++++++++ 1 file changed, 15 insertions(+) create mode 100644 tvix/derivation/src/nix_hash.rs (limited to 'tvix/derivation/src/nix_hash.rs') diff --git a/tvix/derivation/src/nix_hash.rs b/tvix/derivation/src/nix_hash.rs new file mode 100644 index 000000000000..a49d444faa53 --- /dev/null +++ b/tvix/derivation/src/nix_hash.rs @@ -0,0 +1,15 @@ +/// 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 { + let mut output: Vec = vec![0; output_size]; + + for (ii, ch) in input.iter().enumerate() { + output[ii % output_size] ^= ch; + } + + output +} -- cgit 1.4.1