Bitcoin slices

ZERO allocations parse library for Bitcoin data structures.

Data is accessed by providing visitor structs for the data the user is interested in.

Data structures are read-only and parsed data must be in memory, no streaming API.

Tradeoffs

Check the CONS before using this library, use rust-bitcoin if they are too restrictive for your case.

Pros

• Deserialization is amazingly fast, since no allocation is made during parsing.
• Serialization is incredibly fast, since a slice of the serialized data is kept in the structure.
• hashing a little faster because slice are ready without the need of re-serializing data.
• No mandatory dependency.
• No standard.
• Calculate txid and block hash via optional dep bitcoin_hashes or sha2.
• Visitor pattern to visit just what you are interested in.

Cons

• Full data must be in memory, there is no streaming (Read/Write) API.
• Data structure are read-only, cannot be modified.
• Visitor pattern requires user-built data structure for visiting.

Features

Hashing

Use feature sha2 or bitcoin_hashes to calculate hashes of blocks and transactions. The former is faster, the latter is more likely to be in your tree if you work with rust-bitcoin ecosystem's crates.

redb

With the redb feature activated some type allows to be used as value and key in the redb database. Bitcoin slices types are well suited to be used as key and values in the database because conversion from/to slices is immediate.

rust-bitcoin

With the feature bitcoin activated some types allows to be converted in the rust-bitcoin counterpart: for example bsl::Transaction could be converted in bitcoin::Transaction. You may think if you need bitcoin::Transaction you can decode the bytes directly into it without using this library, and is mostly true, but sometimes it may be convenient to use both types, for example using bitcoin slices with datatabases is very convenient because conversion is free, but you may need to access fields more conveniently than writing a visitor for it and thus convert to rust-bitcoin types. Moreover, conversions may leverage type invariants and be faster than starting from a generic byte stream.

Test

sh cargo test

Bench

sh RUSTFLAGS='--cfg=bench' cargo +nightly bench --all-features

sh test bsl::block::bench::block_deserialize ... bench: 289,421 ns/iter (+/- 46,179) test bsl::block::bench::block_deserialize_bitcoin ... bench: 2,719,666 ns/iter (+/- 459,186) test bsl::block::bench::block_sum_outputs ... bench: 288,248 ns/iter (+/- 39,013) test bsl::block::bench::block_sum_outputs_bitcoin ... bench: 2,607,791 ns/iter (+/- 321,212) test bsl::block::bench::hash_block_txs ... bench: 8,406,341 ns/iter (+/- 938,119) test bsl::block::bench::hash_block_txs_bitcoin ... bench: 11,843,590 ns/iter (+/- 1,052,109) test bsl::block::bench::hash_block_txs_sha2 ... bench: 7,891,956 ns/iter (+/- 1,047,439) test bsl::block_header::bench::block_hash ... bench: 1,399 ns/iter (+/- 205) test bsl::block_header::bench::block_hash_bitcoin ... bench: 1,510 ns/iter (+/- 222) test bsl::transaction::bench::tx_deserialize ... bench: 38 ns/iter (+/- 8) test bsl::transaction::bench::tx_deserialize_bitcoin ... bench: 219 ns/iter (+/- 30) test bsl::transaction::bench::txid ... bench: 2,185 ns/iter (+/- 166) test bsl::transaction::bench::txid_bitcoin ... bench: 2,416 ns/iter (+/- 213) test bsl::transaction::bench::txid_sha2 ... bench: 2,085 ns/iter (+/- 216)

• benches ending with _bitcoin use rust-bitcoin
• benches ending with _sha2 use sha2 lib instead of bitcoin_hashes

Comparison against rust-bitcoin

block_deserialize is almost 10 times faster then block_deserialize_bitcoin. It may see unfair comparison since you can't for example iterate transactions from the resulted object in case of block_deserialize, but looking at the sum_outputs example where a visitor is used to access every outputs in a block we se there isn't noticeable difference.

Hashing

block_hash and block_hash_bitcoin use the same code to hash, however bitcoin_slice is about 7% faster because use a slice already available instead of serializing back data. Similar results apply between txid and txid_bitcoin. The performance increase is more notable (30%) between hash_block_txs and hash_block_txs_bitcoin.

*_sha2 are not really representative on virtual CI machines since they are not hardware-accellerated.

Fuzz

Use cargo fuzz Run fuzzing with transaction as target.

sh cargo +nightly fuzz run transaction

Other target available in fuzz/fuzz_targets

Miniminze corpus: cargo +nightly fuzz cmin transaction

Doc

To build docs:

RUSTDOCFLAGS="--cfg docsrs" cargo +nightly doc --all-features --open

Previous work and credits

• Bitiodine use similar visitor pattern (parser credited to Mathias Svensson)
• Some previous work on the idea to parse while reducing allocations in this PR
• Matt Corallo mentioned something like this in a comment in that PR

TODO

• [ ] create rotating buffer that consume and produce keeping a linear memory (rotate back when it can't append), this would overcome a bit the absence of streaming API
• [ ] implements network types
• [ ] add limited time fuzzing in CI