Math redone

[larry0x]

In CosmWasm there are the types Uint{64,128,256,512} but they are basically the same file copy-pasted. Same situation with Int64/128/256/512, Decimal128/512, and SignedDecimal128/512. We want to avoid the duplicate code.

Also, CosmWasm uses bnum underneath which isn't a particularly popular library (only about 500k all time downloads).

Ideas:

• Switch from bnum to crypto-bigint, which is part of RustCrypto, a high quality project, and is the basis of crypto libraries such as elliptic-curve.

• Create a single Uint<T> struct to represent all unsigned integer types:

  type Uint64 = Uint<u64>;
  type Uint128 = Uint<u128>;
  type Uint256 = Uint<crypto_bigint::U256>;
  type Uint512 = Uint<crypto_bigint::U512>;

• Create a Decimal<T> type to represent all fixed-point number types:

  type Decimal128 = Decimal<Uint128>;
  type Decimal256 = Decimal<Uint256>;

• Create a Signed<T> type to represent all signed number types:

  type Int128 = Signed<Uint128>;
  type SignedDecimal128 = Signed<Decimal128>;

[larry0x]

Note: when importing crypto-bigint, make sure to disable default features, otherwise randomness operators are included

[dependencies.crypto-bigint]
git              = "https://github.com/left-curve/crypto-bigint"
branch           = "v0.5.5-grug"
default-features = false
features         = ["serde", "borsh"]

[Rhaki]

Based on the current design:

• Change from bnumto crypt-bigint;
• Remove current Signedand Inttypes created with macros;
• Create a new struct Signed<T>;
• Impls matsh ops for Signed<T>
• Define new Signed(Decimalsand Int) with new macros;

[larry0x]

Completed