Research variable length encoding of CIS-2 token amounts

[concordium]

Research variable length encoding of CIS-2 token amounts

[limemloh]

I have implemented a token amount of u64 using LEB128 for serializing and deserializing and compared it to the current implementation, which is using the serialization and deserialization of u64.

On testnet I deployed the wCCD example with LEB128 and with u64 for token amount. I then initialized each contract, wrapped 10 CCD, transferred 10 wrapped microCCD, unwrapped 10 microCCD while recording the costs.

Both contracts are build with no-std, embedded schema using:

• cargo-concordium 2.0.1
• Rustc nightly-2021-06-09-x86_64-unknown-linux-gnu

Contract	Module Size	Deploy	Init	wrap 10	transfer 10	unwrap 10
Fixed u64	48759 B	53796 NRG	1945 NRG	1890 NRG	2156 NRG	2185 NRG
LEB amount u64	49781 B	54919 NRG	1956 NRG	1903 NRG	2162 NRG	2194 NRG

[limemloh]

From the above results we have concluded to use LEB128 encoding of token amount in CIS2