Better unified piece abstractions using a tiny bit of unsafe
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nazar-pc
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| /// This version is allocated on the heap, for stack-allocated piece see [`PieceArray`]. | ||
| /// | ||
| /// Internally piece contains a record and corresponding witness that together with records root of |
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Naming is weird, though. Maybe we can make:
Piecefor regular piece on stackVecPiecefor heap allocated one
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I would prefer to keep it for now and see how codebase evolves. Piece was the canonical data structure before and it actually looked a lot like current PieceArray, but then it got bigger and it was clear that with future expansion placing it on the stack is not an option.
Now that we have PieceArray and much more usable/useful FlatPieces we can probably reduce reliance on Piece and even replace it with direct Box<PieceArray> where it still remains and get rid of current Piece. But I'd prefer to keep things as is for now and see how it plays out.
… remove the need of `mem::transmute` in some cases
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| impl From<Piece> for Vec<u8> { | ||
| fn from(piece: Piece) -> Self { | ||
| piece.0 | ||
| piece.0.to_vec() |
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This won't do an extra allocation:
https://doc.rust-lang.org/std/primitive.slice.html#method.into_vec
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This is an array, not a slice. Method doesn't seem to exist here. I could likely work around with unsafe, but the whole point of this exercise was to avoid it.
Previous iteration relied on safe code only and had usability shortcomings. With just a bit of
unsafein strategic places it was possible to make API A LOT better. I'm actually proud of what I have achieved here in the end.The main changes are in
pieces.rs. Many of the methods were wrappers round memory slices, but withtransmutewe can turn references to arrays of bytes into references to transparent data structures containing arrays of bytes. With reference out of the data structure we don't need a pair of data structures for mutable and immutable reference scenarios.The biggest piece of code is related to serde support. I basically took previous expanded version and adjusted it to new internal layout of
FlatPiecesbecause derivation was no longer possible.Code contributor checklist: