Midstates are not generic objects; they don't have universal
cryptographic properties and if you are using them you should be using a
specific midstate type. Therefore it shouldn't be part of `GeneralHash` or
`HashEngine`. Furthermore, in practice it seems like `sha2` midstates are
the only ones that anybody uses, at least in bitcoin.
Remove the midstate stuff from the `GeneralHash` and `HashEngine`
traits. Keep the `midstate` functionality as inherent functions if it is
used internally. Keep the functionality on `sha256` as inherent public
functions.
Depending on types being in scope when calling macros is bad practice
but we have mistakenly done so in `internal_macros` when using the
`FromSliceError`.
Use `$crate::FromSliceError` in the macro and remove import statements.
Currently we have a trait `Hash` that is required for `Hmac`, `Hkdf`,
and other use cases. However, it is unegonomic for users who just want
to do a simple hash to have to import the trait.
Add inherent functions to all hash types including those created with
the new wrapper type macros.
This patch introduces some duplicate code but we are trying to make
progress in the hashes API re-write. We can come back and de-dublicate
later.
Includes making `to_byte_array`,`from_byte_array`, `as_byte_array`, and
`all_zeros` const where easily possible.
Depending on things being in scope for macros to use is bad form,
using the fully qualified path is the correct way.
Do not import `str` instead use the fully qualified path to the `core`
re-export.
Use fully qualified instead.
Tobin C. Harding
Matt Corallo