Based on the original work by Justin Moon.
*MSRV unchanged from 1.29.0.*
When `std` is off, `no-std` must be on, and we use the [`alloc`](https://doc.rust-lang.org/alloc/) and core2 crates. The `alloc` crate requires the user define a global allocator.
* Import from `core` and `alloc` instead of `std`
* `alloc` only used if `no-std` is on
* Create `std` feature
* Create `no-std` feature which adds a core2 dependency to polyfill `std::io` features. This is an experimental feature and should be
used with caution.
* CI runs tests `no-std`
* MSRV for `no-std` is 1.51 or so
Taking an external dependency just to convert ints to byte arrays
is somewhat of a waste, especially when Rust isn't very aggressive
about doing cross-crate LTO.
Note that the latest LLVM pattern-matches this, and while I haven't
tested it, that should mean this means no loss of optimization.
Addresses #96.
Turns out it was being used for hex encoding/decoding, so replaced that with the `hex` crate.
i chose to import the `decode` method as:
```
use hex::decode as hex_decode
```
so that it is clear to the reader what is being decoded when it is called. "decode" is such a generic sounding function name that it would get confusing otherwise.
Work is stalled on some other library work (to give better lifetime
requirements on `eventual::Future` and avoid some unsafety), so
committing here.
There are only three errors left in this round :)
Also all the indenting is done, so there should be no more massive
rewrite commits. Depending how invasive the lifetime-error fixes
are, I may even be able to do sanely sized commits from here on.
27 files changed, 3944 insertions(+), 3812 deletions(-) :} I've
started doing whitespace changes as well, I want everything to
be 4-space tabs from now on.
BTW after all this is done I'm gonna indent the entire codebase...
so `git blame` is gonna be totally broken anyway, hence my
capricious cadence of commits.
Sorry for so many things in one commit ... it was an iterative
process depending as I worked on BIP32 to get the other stuff
working. (And I was too lazy to separate it out after the fact.)
A breaking change by the array newtyping is that Show for Sha256dHash
now outputs the slice Show. You have to use `{:x}` to get the old hex
output.