Merge remote-tracking branch 'ni/master'

1 files changed, 34 insertions, 1 deletions

diff --git a/lib/default.nix b/lib/default.nix
index e352c7be..347830e8 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -93,7 +93,13 @@ let
           in
             if max.pos == 0
               then a
-              else "${concatStringsSep ":" lhs}::${concatStringsSep ":" rhs}";
+              else let
+                sep =
+                  if 8 - (length lhs + length rhs) == 1
+                    then ":0:"
+                    else "::";
+              in
+                "${concatStringsSep ":" lhs}${sep}${concatStringsSep ":" rhs}";
 
         drop-leading-zeros =
           let
@@ -112,6 +118,33 @@ let
             (if test ".*::.*" a
               then a
               else group-zeros (drop-leading-zeros a));
+
+    hashToLength = n: s: substring 0 n (hashString "sha256" s);
+
+    dropLast = n: xs: reverseList (drop n (reverseList xs));
+    takeLast = n: xs: reverseList (take n (reverseList xs));
+
+    # Split string into list of chunks where each chunk is at most n chars long.
+    # The leftmost chunk might shorter.
+    # Example: stringToGroupsOf "123456" -> ["12" "3456"]
+    stringToGroupsOf = n: s: let
+      acc =
+        foldl'
+          (acc: c: if stringLength acc.chunk < n then {
+            chunk = acc.chunk + c;
+            chunks = acc.chunks;
+          } else {
+            chunk = c;
+            chunks = acc.chunks ++ [acc.chunk];
+          })
+          {
+            chunk = "";
+            chunks = [];
+          }
+          (stringToCharacters s);
+    in
+      filter (x: x != []) ([acc.chunk] ++ acc.chunks);
+
   };
 in