Add CompactBinary proof serialization

[Leo-Besancon]

This PR, along with it's counterpart in stwo-cairo (starkware-libs/stwo-cairo#1136), aims to provide compact serialization of Starknet proofs in order to limit network usage.

• Added CompactBinary trait in stwo_cairo_prover/crates/cairo-serialize/src/compact.rs, and implemented this trait for all structures needed.
• Added a #[derive(CompactBinary)] proc macro to implement the trait for structures composed of fields implementing it. Note that the proc macro is only expected to produce a 0 version, if a given structure is to be updated it's implementation should be done manually, while keeping back-compatibility of all previous serialization versions for this structure. See stwo_cairo_prover/crates/cairo-serialize-derive/src/lib.rs

[reviewable-StarkWare]

This change is 

[0xLucqs]

add some tests assert_eq!(deserialize(serialize(a))

• add the doc describing the spec (might also be good to add it above the trait

[0xLucqs]

this crate is using nightly so i think you should use if-let-chains which would make the whole thing cleaner

[Leo-Besancon]

Nice! Done in 27587b1

[gilbens-starkware]

Reviewable status: 0 of 10 files reviewed, 2 unresolved discussions (waiting on @0xLucqs)

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crates/stwo/src/core/compact_binary.rs line 384 at r3 (raw file):

#[cfg(test)]
mod tests {
    use num_traits::One;

Move the tests to a file module.

Code quote:

#[cfg(test)]
mod tests {
    use num_traits::One;

[Leo-Besancon]

Reviewable status: 0 of 10 files reviewed, 2 unresolved discussions (waiting on @0xLucqs)

crates/stwo/src/core/compact_binary.rs line 384 at r3 (raw file):

#[cfg(test)]
mod tests {
    use num_traits::One;

Move the tests to a file module.

Code quote:

#[cfg(test)]
mod tests {
    use num_traits::One;

Thank you, done in the latest commit.

[gilbens-starkware]

Reviewed 4 of 9 files at r2, 1 of 2 files at r4, all commit messages.
Reviewable status: 5 of 11 files reviewed, 3 unresolved discussions (waiting on @0xLucqs)

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crates/compact-binary/README.md line 10 at r4 (raw file):

- `cairo-serde`: the proof is first converted into a `Vec<FieldElement>`, that is then serialized in a serde json format.

The aim is to design and implement a third proof serialization format, `compact-binary`, where the proof is serialized as a `Vec<u8>` in a compact way.

Suggestion:

This crate implements a third proof serialization format, `compact-binary`, where the proof is serialized as a `Vec<u8>` in a compact way.

---

crates/compact-binary/src/lib.rs line 43 at r4 (raw file):

/// | example_proof.cairo_serde          | cairo-serde       |           2 448 494  |  - 3.1 % |
/// | example_proof.compact_bin_unzipped | compact-binary    |             834 606  | - 67.0 % |
/// | example_proof.compact_bin_zipped   | compact-binary    |             582 932  | - 76.9 % |

This appears in the readme, I think it can be removed from here.

Code quote:

/// ## Benchmarks
/// The following table shows the size of a proof serialized in different formats, using the
/// `compact-binary` format with and without zipping.
///
/// | File                               | Format            | Size on disk (bytes) | Gain     |
/// |------------------------------------|-------------------|---------------------:|---------:|
/// | example_proof.base_json            | json              |           2 528 114  |    --    |
/// | example_proof.cairo_serde          | cairo-serde       |           2 448 494  |  - 3.1 % |
/// | example_proof.compact_bin_unzipped | compact-binary    |             834 606  | - 67.0 % |
/// | example_proof.compact_bin_zipped   | compact-binary    |             582 932  | - 76.9 % |

[gilbens-starkware]

Reviewable status: 5 of 11 files reviewed, 4 unresolved discussions (waiting on @0xLucqs and @Leo-Besancon)

---

crates/compact-binary/README.md line 37 at r4 (raw file):

Note that the proc macro supports the `#[zipped]` attribute to specify that a given field should be zipped.
- Added error handling through `CompactDeserializeError` enum and `CompactSerializeError` struct
- Implemented the trait for structures in `stwo` crate used for CairoProofs.

I’d suggest changing the wording here from past tense (“Added”, “Implemented”) to present/descriptive tense, since this section should describe the current state of the code rather than the history of changes. For example:

• “Added CompactBinary trait …” → “CompactBinary trait in crates/compact-binary/src/lib.rs …”
• “Implemented this trait …” → “Implementations of this trait …”
• “Added error handling …” → “Error handling through …”

Code quote:

- Added `CompactBinary` trait in `crates/compact-binary/src/lib.rs`, and implemented this trait for all structures needed.
- Added a `#[derive(CompactBinary)]` proc macro to implement the trait for structures composed of fields implementing it. Note that the proc macro is only expected to produce a `0` version, if a given structure is to be updated it's implementation should be done manually, while keeping back-compatibility of all previous serialization versions for this structure. See `crates/compact-binary-derive/src/lib.rs`
Note that the proc macro supports the `#[zipped]` attribute to specify that a given field should be zipped.
- Added error handling through `CompactDeserializeError` enum and `CompactSerializeError` struct
- Implemented the trait for structures in `stwo` crate used for CairoProofs.

[gilbens-starkware]

@gilbens-starkware reviewed 1 of 7 files at r1, 3 of 9 files at r2, 1 of 1 files at r3, 1 of 2 files at r4, 2 of 2 files at r5, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @0xLucqs)