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Diffstat (limited to 'pkgs/jenkinsWithPlugins/fromBase64.nix')
| -rw-r--r-- | pkgs/jenkinsWithPlugins/fromBase64.nix | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/pkgs/jenkinsWithPlugins/fromBase64.nix b/pkgs/jenkinsWithPlugins/fromBase64.nix new file mode 100644 index 0000000..3130f9c --- /dev/null +++ b/pkgs/jenkinsWithPlugins/fromBase64.nix @@ -0,0 +1,74 @@ +strBase64: + +let + + inherit (builtins) + concatStringsSep genList stringLength substring trace ; + + base64 = { + # n=0; for l in {A..Z} {a..z} {0..9} + /; do printf '"%s" = %2s; ' $l $n; (( n++ )); (( n % 8 )) || echo; done + "A" = 0; "B" = 1; "C" = 2; "D" = 3; "E" = 4; "F" = 5; "G" = 6; "H" = 7; + "I" = 8; "J" = 9; "K" = 10; "L" = 11; "M" = 12; "N" = 13; "O" = 14; "P" = 15; + "Q" = 16; "R" = 17; "S" = 18; "T" = 19; "U" = 20; "V" = 21; "W" = 22; "X" = 23; + "Y" = 24; "Z" = 25; "a" = 26; "b" = 27; "c" = 28; "d" = 29; "e" = 30; "f" = 31; + "g" = 32; "h" = 33; "i" = 34; "j" = 35; "k" = 36; "l" = 37; "m" = 38; "n" = 39; + "o" = 40; "p" = 41; "q" = 42; "r" = 43; "s" = 44; "t" = 45; "u" = 46; "v" = 47; + "w" = 48; "x" = 49; "y" = 50; "z" = 51; "0" = 52; "1" = 53; "2" = 54; "3" = 55; + "4" = 56; "5" = 57; "6" = 58; "7" = 59; "8" = 60; "9" = 61; "+" = 62; "/" = 63; + }; + + quartet_to_int24 = q: + # https://en.wikipedia.org/wiki/Base64 + let + s = n: assert (stringLength q == 4); substring (3 - n) 1 q; + d = n: base64.${s n}; + in if s 0 != "=" then + 64 * (64 * (64 * (d 3) + (d 2)) + (d 1)) + (d 0) + else if s 1 != "=" then + 64 * (64 * (64 * (d 3) + (d 2)) + (d 1)) / 256 # right shift by 8 bits + else + 64 * (64 * (64 * (d 3) + (d 2))) / 65536 # right shift by 16 bits + ; + + int24_to_hex = i: # 16777215 (0xFFFFFF, 2^24-1) max + let + hex = "0123456789abcdef"; + toHex = n: + let + d = n / 16; + r = n - 16 * d; + in "${if d != 0 then toHex d else ""}${substring r 1 hex}"; + in assert (0 <= i && i <= 16777215); toHex i; + + quartets = s: + let + l = stringLength s; + h = substring 0 4 s; + t = substring 4 (l - 4) s; + in [h] ++ (if t != "" then quartets t else []); + + + quartet_to_hex = q: # base64 quartet into hex with padding + let + i = quartet_to_int24 q; + h = int24_to_hex i; + s = if substring 2 1 q == "=" then 1 + else if substring 3 1 q == "=" then 2 + else 3; # number of bytes + w = s * 2; # number of hexadecimal digits + filler = concatStringsSep "" (genList (_: "0") (w - stringLength h)); + in "${filler}${h}"; + +/* + + FIXME: usage of library functions like concatMapString + causes very cryptic errors: + + # nix-instantiate --eval --expr 'import ./fromBase64.nix "kjOzmCPxyw0bPciMsGSh5q+bT9g="' --show-trace + error: while evaluating anonymous function at .../fromBase64.nix:1:1, called from (string):1:18: + value is a function while a set was expected, at .../fromBase64.nix:3:4 + +*/ + +in concatStringsSep "" (map quartet_to_hex (quartets strBase64)) + |