zigzag_encode

Maps a signed integer to an unsigned one so that small magnitudes stay small: 0, -1, 1, -2, 2, ... become 0, 1, 2, 3, 4, .... Varint formats (Protocol Buffers sint, Kiwi) encode signed values this way before LEB128, so that -1 takes one byte instead of ten.

The result does not depend on the integer width: an i32 widened to i64 encodes to the same value as with 32-bit zigzag.

Import

use helpers4::bytes::zigzag_encode;

Cargo feature bytes (enabled by default). To compile only this module:

cargo add helpers4 --no-default-features --features bytes

or in Cargo.toml:

[dependencies]
helpers4 = { version = "0.0.9", default-features = false, features = ["bytes"] }

Signature

pub fn zigzag_encode(value: i64) -> u64

Parameters

Parameter	Type	Description
value	i64	The signed integer.

Returns

u64 — The zigzag-encoded value; zigzag_decode reverses it.

Examples

use helpers4::bytes::zigzag_encode;

assert_eq!(zigzag_encode(0), 0);
assert_eq!(zigzag_encode(-1), 1);
assert_eq!(zigzag_encode(1), 2);
assert_eq!(zigzag_encode(i64::MIN), u64::MAX);

Source

src/bytes/zigzag_encode.rs