Provides an unsigned integer type IntOrAString that can be used to represent
a packed string in a single evm word.
Tries to do as little as possible, respecting the basic constraint, which is that we only have 32 bytes of data to work with. There are no fallbacks, errors, conditionals or unsupported edge cases and minimal jumps generally.
Every possible IntOrAString value will produce a string when toString is
called, and vice versa, every possible string will create an IntOrAString.
The length of the string in the packed representation is read from the leftmost
byte, using the rightmost 5 bits of that byte. By using 5 bits for the length we
naturally achieve a 31 byte limit on the string data, with the "weird" side
effect that strings are truncated to mod 32 whatever their original length was,
on both toString and fromString.
Probably the caller does not want strings truncating to a mod of their length,
so they should ensure that they don't feed anything that they don't want
truncated into this lib.
LibIntOrAString is careful to zero out data beyond input string values upon
creation, but will reproduce any garbage bytes from an IntOrAString into
memory on the round trip back to a string. Generally string values are bound
by their length, so any code that reads the produced string should not enter
these garbage bytes in memory anyway.
LibIntOrAString sets the high bit of IntOrAString values that it creates from
strings to 1 to ensure that they are always treated as truthy values. I.e. no
string input ever maps to 0.
LibIntOrAString will interpret 0 and many other integer values that it cannot
produce as strings, if high/garbage bits are set/unset in ways it doesn't care
about when reading integers. It is strongly recommended to only roundtrip values
through compatible versions of this lib.
Uses nixos.
Install nix develop - https://nixos.org/download.html.
Run nix develop in this repo to drop into the shell. Please ONLY use the nix
version of foundry for development, to ensure versions are all compatible.
Read the flake.nix file to find some additional commands included for dev and
CI usage.
Everything is under DecentraLicense 1.0 (DCL-1.0) which can be found in LICENSES/.
This is basically CAL-1.0 which is an open source license
https://opensource.org/license/cal-1-0
The non-legal summary of DCL-1.0 is that the source is open, as expected, but also user data in the systems that this code runs on must also be made available to those users as relevant, and that private keys remain private.
Roughly it's "not your keys, not your coins" aware, as close as we could get in legalese.
This is the default situation on permissionless blockchains, so shouldn't require any additional effort by dev-users to adhere to the license terms.
This repo is REUSE 3.2 compliant https://reuse.software/spec-3.2/ and compatible
with reuse tooling (also available in the nix shell here).
nix develop -c rainix-sol-legal
Contributions are welcome under the same license as above.
Contributors agree and warrant that their contributions are compliant.