src/crypto/keccak/hex.bend

0x9ee2e9a299991dcc089fe22c7f3ceb5f · 33 lines · 0 definitions

1import Base
2
3def hex_digit_if(x: U32, small: Bool) -> Char:
4  match small:
5    case True{}:
6      Chr{(48 + x : U32)}
7    case False{}:
8      Chr{(87 + x : U32)}
9
10def hex_digit(+x: U32) -> Char:
11  hex_digit_if(x, U32.is_lt(x, 10))
12
13def hex_word_go(n: Nat, +x: U32, acc: String) -> String:
14  match n:
15    case 0n:
16      acc
17    case 1n+p:
18      hex_word_go(p, U32.shrn(x, 4n), SCon{hex_digit((x .&. 15 : U32)), acc})
19
20def hex_byte(+x: U32) -> String:
21  SCon{hex_digit(U32.shrn(x,4n)),SCon{hex_digit(U32.and(x,15)),SNil{}}}
22
23def hex_word(+x: U32) -> String:
24  hex_byte(U32.and(x,255)) ++ hex_byte(U32.and(U32.shrn(x,8n),255)) ++ hex_byte(U32.and(U32.shrn(x,16n),255)) ++ hex_byte(U32.shrn(x,24n))
25
26# Formatting helper consumes eight words; it does not create a digest list.
27def hex_walk(n: Nat, +index: U32, pair: Array<U32> & U32) -> String:
28  match n pair:
29    case 0n Tuple{a,w}: hex_word(w)
30    case 1n+p Tuple{a,w}: hex_word(w) ++ hex_walk(p,U32.inc(index),Array.get(U32,a,index))
31
32def hex(a: Array<U32>) -> String:
33  hex_walk(7n,1,Array.get(U32,a,0))