Implement decoding of Ethereum arguments/call results.

This commit is contained in:
Fang 2018-03-14 21:53:48 +01:00
parent f28b9f7b60
commit 2b76a23b44
2 changed files with 116 additions and 0 deletions

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@ -80,6 +80,110 @@
%label s+l.dob %label s+l.dob
== ==
:: ::
:: decoding
::
:: for details on encoding, see below.
::
++ decode-results
:> rex: string of hex bytes with leading 0x.
|= [rex=@t tys=(list etyp)]
(decode-arguments (rsh 3 2 rex) tys)
::
++ decode-arguments
:> res: string of hex bytes without leading 0x.
|= [res=@t tys=(list etyp)]
:> wos: input as list of 32 byte words in hex.
=/ wos=(list @t) (rip 9 res)
:> win: index of the word to process.
=| win=@ud
:> das: resulting data, should match {tys}.
=| das=(list data)
|- ^+ das
?~ tys (flop `(list data)`das)
=* typ i.tys
?: (gte win (lent wos)) ~|(%insufficient-data !!)
=- $(das [dat das], win nin, tys t.tys)
::=< (decode-next win i.tys) ::TODO urbit/arvo#673
|^ ::|% ++ decode-next |= [win=@ud typ=etyp]
^- [nin=@ud dat=data]
=+ wor=(snag win wos)
?+ typ
~| [%unsupported-type typ]
!!
::
?(%address %bool %uint) :: %int %real %ureal
:- +(win)
?- typ
%address address+(rash wor hex)
%uint uint+(rash wor hex)
%bool bool+=(0 (rash wor hex))
==
::
%string
=+ $(typ %bytes)
?> ?=(%bytes -.dat)
[nin %string (trip (swp 3 q.p.dat))]
::
%bytes
:+ +(win) %bytes
:: find the word index of the actual data.
=/ lic=@ud (div (rash wor hex) 32)
:: learn the bytelength of the data.
=/ len=@ud (rash (snag lic wos) hex)
(decode-bytes-n +(lic) len)
::
[%bytes-n *]
:- (add win +((div n.typ 32)))
[%bytes-n (decode-bytes-n win n.typ)]
::
[%array *]
:+ +(win) %array
:: find the word index of the actual data.
=. win (div (rash wor hex) 32)
:: read the elements from their location.
::TODO see ++decode-array-n
:: %^ decode-array-n t.typ +(win)
:: (rash (snag win wos) hex)
=/ len=@ud (rash (snag win wos) hex)
=. win +(win)
=| els=(list data)
|- ^+ els
?: =(len 0) (flop els)
=+ ^$(typ t.typ, win win)
$(els [dat els], win nin, len (dec len))
::
[%array-n *]
::TODO see ++decode-array-n
:: (decode-array-n t.typ win n.typ)
=| els=(list data)
|-
?: =(n.typ 0) [win %array-n (flop els)]
~& [%arr-left n.typ win]
=+ ^$(typ t.typ, win win)
$(els [dat els], win nin, n.typ (dec n.typ))
==
::
++ decode-bytes-n
|= [fro=@ud bys=@ud]
^- octs
:: parse {bys} bytes from {fro}.
=- [bys (rash - hex)]
%^ end 3 (mul 2 bys)
%+ can 9
%+ turn
(swag [fro +((div bys 32))] wos)
|=(a=@t [1 a])
::
::TODO uncomment and use once urbit/arvo#673 gets resolved/a workaround.
:: ++ decode-array-n
:: |= [typ=etyp fro=@ud len=@ud]
:: =| els=(list data)
:: |- ^+ els
:: ?: =(len 0) (flop els)
:: =+ (decode-next typ fro)
:: $(els [dat els], fro nin, len (dec len))
--
::
:: encoding :: encoding
:: ::
:: ABI spec used for reference: :: ABI spec used for reference:

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@ -1,5 +1,17 @@
:: ::
|% |%
++ etyp
$? :: static
%address %bool
%int %uint
%real %ureal
[%bytes-n n=@ud]
:: dynamic
%bytes %string
[%array-n t=etyp n=@ud]
[%array t=etyp]
==
::
++ data :> typed data ++ data :> typed data
$% [%address p=@ux] $% [%address p=@ux]
[%string p=tape] [%string p=tape]