Function read_bin_advance

nodedb-query/src/msgpack_scan/reader.rs:290–303

Read a `bin` value at `*off`, advancing `*off` past it. Zero-copy — the returned slice borrows from `buf`. Returns `None` for non-bin tags or truncated input.

(buf: &'a [u8], off: &mut usize)

/// the returned slice borrows from `buf`. Returns `None` for non-bin tags
/// or truncated input.
pub fn read_bin_advance<'a>(buf: &'a [u8], off: &mut usize) -> Option<&'a [u8]> {
    let tag = get(buf, *off)?;
    let (len, header) = match tag {
        BIN8 => (get(buf, *off + 1)? as usize, 2),
        BIN16 => (read_u16_be(buf, *off + 1)? as usize, 3),
        BIN32 => (read_u32_be(buf, *off + 1)? as usize, 5),
        _ => return None,
    };
    let start = *off + header;
    let end = start + len;
    let data = buf.get(start..end)?;
    *off = end;
    Some(data)
}

/// Read an unsigned integer that fits in a `u32` at `*off`, advancing `*off`
/// past it. Accepts positive fixint, uint8, uint16, uint32. Returns `None`