shrub/pkg/arvo/lib/bitcoin-utils.hoon

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:: lib/bitcoin-utils.hoon
:: Utilities for working with BTC data types and transactions
::
/- *bitcoin
~% %bitcoin-utils-lib ..part ~
|%
::
:: TODO: move this bit/byt stuff to zuse
:: bit/byte utilities
::
::
:: +blop: munge bit and byt sequences (cat, flip, take, drop)
::
++ blop
~/ %blop
|_ =bloq
+$ biyts [wid=@ud dat=@]
++ cat
|= bs=(list biyts)
^- biyts
:- (roll (turn bs |=(b=biyts -.b)) add)
(can bloq (flop bs))
:: +flip: flip endianness while preserving lead/trail zeroes
::
++ flip
|= b=biyts
^- biyts
[wid.b (rev bloq b)]
:: +take: take n bloqs from front
:: pads front with extra zeroes if n is longer than input
::
++ take
|= [n=@ b=biyts]
^- biyts
?: (gth n wid.b)
[n dat.b]
[n (rsh [bloq (sub wid.b n)] dat.b)]
:: +drop: drop n bloqs from front
:: returns 0^0 if n >= width
::
++ drop
|= [n=@ b=biyts]
^- biyts
?: (gte n wid.b)
0^0x0
=+ n-take=(sub wid.b n)
[n-take (end [bloq n-take] dat.b)]
--
++ byt ~(. blop 3)
::
++ bit
~/ %bit
=/ bl ~(. blop 0)
|%
++ cat cat:bl:bit
++ flip flip:bl:bit
++ take take:bl:bit
++ drop drop:bl:bit
++ from-atoms
|= [bitwidth=@ digits=(list @)]
^- bits
%- cat:bit
%+ turn digits
|= a=@
?> (lte (met 0 a) bitwidth)
[bitwidth `@ub`a]
:: +to-atoms: convert bits to atoms of bitwidth
::
++ to-atoms
|= [bitwidth=@ bs=bits]
^- (list @)
=| res=(list @)
?> =(0 (mod wid.bs bitwidth))
|-
?: =(0 wid.bs) res
%= $
res (snoc res dat:(take:bit bitwidth bs))
bs (drop:bit bitwidth bs)
==
--
:: big endian sha256: input and output are both MSB first (big endian)
::
++ sha256
~/ %sha256
|= =byts
^- hexb
%- flip:byt
[32 (shay (flip:byt byts))]
::
++ dsha256
~/ %dsha256
|= =byts
(sha256 (sha256 byts))
::
++ hash-160
~/ %hash-160
|= val=byts
^- hexb
=, ripemd:crypto
:- 20
%- ripemd-160
(sha256 val)
::
:: hxb: hex parsing utilities
::
++ hxb
~% %hxb ..blop ~
|%
++ from-cord
~/ %from-cord
|= h=@t
^- hexb
?: =('' h) 1^0x0
:: Add leading 00
::
=+ (lsh [3 2] h)
:: Group by 4-size block
::
=+ (rsh [3 2] -)
:: Parse hex to atom
::
:: TODO: replace with (met 3 h)
:- (div (met 3 h) 2)
`@ux`(rash - hex)
::
++ to-cord
~/ %to-cord
|= =hexb
^- cord
(en:base16:mimes:html hexb)
--
::
:: +csiz: CompactSize integers (a Bitcoin-specific datatype)
:: https://btcinformation.org/en/developer-reference#compactsize-unsigned-integers
:: - encode: big endian to little endian
:: - decode: little endian to big endian
::
++ csiz
~% %csiz ..blop ~
|%
++ en
~/ %en
|= a=@
^- hexb
=/ l=@ (met 3 a)
?: =(l 1) 1^a
?: =(l 2) (cat:byt ~[1^0xfd (flip:byt 2^a)])
?: (lte l 4) (cat:byt ~[1^0xfe (flip:byt 4^a)])
?: (lte l 8) (cat:byt ~[1^0xff (flip:byt 8^a)])
~|("Cannot encode CompactSize longer than 8 bytes" !!)
::
++ de
~/ %de
|= h=hexb
^- [n=hexb rest=hexb]
=/ s=@ux dat:(take:byt 1 h)
?: (lth s 0xfd) [1^s (drop:byt 1 h)]
~| "Invalid compact-size at start of {<h>}"
=/ len=bloq
?+ s !!
%0xfd 1
%0xfe 2
%0xff 3
==
:_ (drop:byt (add 1 len) h)
%- flip:byt
(take:byt (bex len) (drop:byt 1 h))
:: +dea: atom instead of hexb for parsed CompactSize
::
++ dea
|= h=hexb
^- [a=@ rest=hexb]
=> (de h)
[dat.n rest]
--
--