Adds new module `string` to be later converted to its own
crate. The module currently contains the FromHexStr trait and an error
type to be used for implementing hex parsing on types. This change
also adds implementations of FromHexStr for types with a single u32
member such as `Sequence(pub u32)`. All structs that match the
following regex have been given this implementation
`\(u32\)` and `\(pub u32\)`. All implementations have associated
unit tests matching all possible cases. NonStandardSighashType has
been ommitted from this change as it is an error and should not be
constructed using the methods added in this change.
Adds parse::hex_u32 for future use to be made generic to allow
different sizes of integers to be parsed from hex strings.
The error type FromHexError implements required traits such as
Display and std::error::Error
Currently the types in the block module have longer names than
necessary, "header" and "version" identifiers contain the word "block",
this is unnecessary because we can write `block::Header` instead of
`BlockHeader` when context is required. This allows us to use the naked
type `Header` inside the `block` module with no loss of clarity.
We are stuck with `BlockHash` because the type is defined along with all
the other hash types in `hash_types`, leave it as is for now but
re-export it from the `block` module to assist in putting types that are
used together in scope in the same place, making import statements more
ergonomic.
A zero default value for `Target` and `Work` has no significance and/or
usecase, remove the derived `Default` implementation.
Includes making `Target::ZERO` public.
Currently we use the `Uint256` type to represent two proof of work
integers, namely target and difficulty (work).
It would be nice to not have a public integer type that is not fully
implemented (i.e., does not implement arithmetic etc as do integer types
in stdlib). Instead of implementing all the stdlib functions we can
instead add two new wrapper types, since these are not general purpose
integers they do not need to implement anything we do not need to use.
- Add a `pow` module.
- Put a modified version of `Uint256` to `pow`.
- Add two new wrapper types `Target` and `Difficulty`.
- Only implement methods that we use on each type.
Note this patch does not remove the original `Uint256`, that will be
done as a separate patch.