lib: bitAnd, bitOr, bitXor

This commit is contained in:
volth 2018-06-01 20:56:19 +00:00
parent 425ff431ab
commit 0addac3b0a
2 changed files with 47 additions and 4 deletions

View file

@ -56,10 +56,10 @@ let
hasAttr head isAttrs isBool isInt isList isString length hasAttr head isAttrs isBool isInt isList isString length
lessThan listToAttrs pathExists readFile replaceStrings seq lessThan listToAttrs pathExists readFile replaceStrings seq
stringLength sub substring tail; stringLength sub substring tail;
inherit (trivial) id const concat or and boolToString mergeAttrs inherit (trivial) id const concat or and bitAnd bitOr bitXor
flip mapNullable inNixShell min max importJSON warn info boolToString mergeAttrs flip mapNullable inNixShell min max
nixpkgsVersion version mod compare splitByAndCompare importJSON warn info nixpkgsVersion version mod compare
functionArgs setFunctionArgs isFunction; splitByAndCompare functionArgs setFunctionArgs isFunction;
inherit (fixedPoints) fix fix' extends composeExtensions inherit (fixedPoints) fix fix' extends composeExtensions
makeExtensible makeExtensibleWithCustomName; makeExtensible makeExtensibleWithCustomName;

View file

@ -1,4 +1,38 @@
{ lib }: { lib }:
let
zipIntBits = f: x: y:
let
# (intToBits 6) -> [ 0 1 1 ]
intToBits = x:
if x==0 then
[]
else
let
headbit = if (x / 2) * 2 != x then 1 else 0; # x & 1
tailbits = if x < 0 then 9223372036854775807 + ((x+1) / 2) else x / 2; # x >>> 1
in
[headbit] ++ (intToBits tailbits);
# (bitsToInt [ 0 1 1 ]) -> 6
bitsToInt = l:
if l==[] then
0
else
(builtins.head l) + (2 * (bitsToInt (builtins.tail l)));
zipListsWith' = fst: snd:
if fst==[] && snd==[] then
[]
else if fst==[] then
[(f 0 (builtins.head snd))] ++ (zipListsWith' [] (builtins.tail snd))
else if snd==[] then
[(f (builtins.head fst) 0 )] ++ (zipListsWith' (builtins.tail fst) [] )
else
[(f (builtins.head fst) (builtins.head snd))] ++ (zipListsWith' (builtins.tail fst) (builtins.tail snd));
in
assert (builtins.isInt x) && (builtins.isInt y);
bitsToInt (zipListsWith' (intToBits x) (intToBits y));
in
rec { rec {
/* The identity function /* The identity function
@ -31,6 +65,15 @@ rec {
/* boolean and */ /* boolean and */
and = x: y: x && y; and = x: y: x && y;
/* bitwise and */
bitAnd = builtins.bitAnd or zipIntBits (a: b: if a==1 && b==1 then 1 else 0);
/* bitwise or */
bitOr = builtins.bitOr or zipIntBits (a: b: if a==1 || b==1 then 1 else 0);
/* bitwise xor */
bitXor = builtins.bitXor or zipIntBits (a: b: if a!=b then 1 else 0);
/* Convert a boolean to a string. /* Convert a boolean to a string.
Note that toString on a bool returns "1" and "". Note that toString on a bool returns "1" and "".
*/ */