From f3a998037a3f3295ff94a62a523aee38b569c4ea Mon Sep 17 00:00:00 2001
From: Artemis Tosini <me@artem.ist>
Date: Thu, 18 Jul 2024 21:19:43 +0000
Subject: [PATCH] Improve encode_nix32 comment

---
 .../base/fetch_and_unpack_nix_substituter.rs  | 25 +++++++++++++------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/src/action/base/fetch_and_unpack_nix_substituter.rs b/src/action/base/fetch_and_unpack_nix_substituter.rs
index 7c9f918..66528be 100644
--- a/src/action/base/fetch_and_unpack_nix_substituter.rs
+++ b/src/action/base/fetch_and_unpack_nix_substituter.rs
@@ -614,17 +614,26 @@ fn encode_nix32(input: &[u8]) -> String {
     // The output is backwards and bits are grouped
     // from the least significant bit in each byte
     // instead of the most significant bit.
-    // e.g. encoding "Meow" gives us:
+    // e.g. for a 4-byte input, bits are mapped from input to output like this:
+    // Out No.: 5 5 5 6 6 6 6 6 | 3 4 4 4 4 4 5 5 | 2 2 2 2 3 3 3 3 | 0 0 1 1 1 1 1 2
+    // Out Bit: 2 1 0 4 3 2 1 0 | 0 4 3 2 1 0 4 3 | 3 2 1 0 4 3 2 1 | 1 0 4 3 2 1 0 4
+    //
+    // where "Out No." is the index of the output charater responsible for a given bit;
+    // and "Out Bit" is the value of a given bit within the output character,
+    // with 4 being most significant and 0 being least significant.
+    //
+    // for "Meow" we'd get:
     // Char:       M (0x4d)          e (0x65)          o (0x6f)          w (0x77)
     // Value:   0 1 0 0 1 1 0 1 | 0 1 1 0 0 1 0 1 | 0 1 1 0 1 1 1 1 | 0 1 1 1 0 1 1 1
     // Out No.: 5 5 5 6 6 6 6 6 | 3 4 4 4 4 4 5 5 | 2 2 2 2 3 3 3 3 | 0 0 1 1 1 1 1 2
-    // Out Bit: 2 1 0 4 3 2 1 0 | 0 5 4 3 2 1 4 3 | 3 2 1 0 4 3 2 1 | 1 0 4 3 2 1 0 4
-    //
-    // where "Out No." is the index of the output charater responsible for a given bit,
-    // and 2**"Out Bit" is the value of a given bit for its output character.
-    //
-    // In this example, characters 0 to 6 have values
-    // 0x01, 0x1b, 0x16, 0x1e, 0x19, 0xa, 0xd.
+    // Out Bit: 2 1 0 4 3 2 1 0 | 0 4 3 2 1 0 4 3 | 3 2 1 0 4 3 2 1 | 1 0 4 3 2 1 0 4
+    // 6: 01101 (0x0d)
+    // 5: 01010 (0x0a)
+    // 4: 11001 (0x19)
+    // 3: 11110 (0x1e)
+    // 2: 10110 (0x16)
+    // 1: 11011 (0x1b)
+    // 0: 00001 (0x01)
     // Indexing into the alphabet gives us "1vnyrad"
 
     for char_no in 0..length {