Function encode_u64 

pub fn encode_u64(v: u64, case: HexCase, buf: &mut [u8; 16]) -> &[u8] 

Writes v as hex into buf and returns the written subslice.

Digits are written right-aligned with leading zeros trimmed, so the result borrows the tail of buf. Zero encodes as "0".

Signed values should be cast with as u64, which yields the two’s complement representation that both to_hex and Spark’s hex produce for negative input.

Example

The caller owns the buffer and can reuse it across calls; each call returns a fresh subslice of it, borrowed for as long as buf is:

use datafusion_common::utils::hex::{HexCase, encode_u64};

let mut buf = [0u8; 16];
assert_eq!(encode_u64(0xAB, HexCase::Lower, &mut buf), b"ab");
assert_eq!(encode_u64(0, HexCase::Lower, &mut buf), b"0");