bitcoin-asmap 0.1.19

Bit-exact Rust reimplementation of Bitcoin Core's ASMAP decoder, interpreter, and structural validator for mapping IP addresses to autonomous system numbers (ASNs).
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// ---------------- [ File: bitcoin-asmap/src/decode_match.rs ]
/*!
This function, `decode_match`, decodes a match value from
a provided iterator of boolean values. The iterator `bitpos`
represents the current position in the ASMAP data, and
`endpos` represents the end position of the data. The
purpose of this function is to decode a match value from the
compact representation in the ASMAP data.

The function uses a static vector `MATCH_BIT_SIZES`, which
contains a list of possible match bit sizes.

The C++ code provided for this function calls the
`DecodeBits` function with `bitpos`, `endpos`, a minimum bit
size of 2, and the `MATCH_BIT_SIZES` vector.

In Rust, the `decode_match` function will have a similar
structure. It will call a Rust implementation of the
`DecodeBits` function with the given iterator, end position,
a minimum bit size of 2, and the `MATCH_BIT_SIZES`
vector. The `todo!();` macro is a placeholder that should be
replaced with the Rust implementation that follows the same
logic as the C++ code provided.
*/

crate::ix!();

lazy_static!{
    static ref MATCH_BIT_SIZES: Vec<u8> = vec!{1, 2, 3, 4, 5, 6, 7, 8};
}

/// Decode a match value (pattern + sentinel bit) from `asmap`.
pub fn decode_match(asmap: &[bool], pos: &mut usize) -> u32 {
    trace!(pos = *pos, "decode_match");
    decode_bits(asmap, pos, 2, &MATCH_BIT_SIZES)
}