12 releases
0.1.11 | Jun 9, 2024 |
---|---|
0.1.10 | Feb 12, 2023 |
0.1.8 | Jan 27, 2023 |
0.1.5 | Jun 13, 2022 |
0.1.2 | Nov 26, 2021 |
#271 in Encoding
Used in 2 crates
63KB
1.5K
SLoC
vu64
The variable length integer encoding of u64. This is a simple and fast encoder/decoder.
Features
- integer value length compaction
- minimum support rustc 1.58.1 (db9d1b20b 2022-01-20)
format pattern
Prefix | Precision | Total Bytes |
---|---|---|
0xxxxxxx |
7 bits | 1 byte |
10xxxxxx |
14 bits | 2 bytes |
110xxxxx |
21 bits | 3 bytes |
1110xxxx |
28 bits | 4 bytes |
11110xxx |
35 bits | 5 bytes |
111110xx |
42 bits | 6 bytes |
1111110x |
49 bits | 7 bytes |
11111110 |
56 bits | 8 bytes |
11111111 |
64 bits | 9 bytes |
This format is a like vint64
,
but 0x00 is represented by 0x00.
Examples
Encode
use vu64::encode;
assert_eq!(encode(0x0f0f).as_ref(), &[0x8F, 0x3c]);
Decode
use vu64::decode;
let slice = [0x8F, 0x3c].as_ref();
assert_eq!(decode(slice).unwrap(), 0x0f0f);
Encode and decode
use vu64::{encode, decode};
let val = 1234;
assert_eq!(decode(encode(val).as_ref()).unwrap(), val);
Read from buffer and decode
use vu64::io::ReadVu64;
let vec: Vec<u8> = vec![0xFF, 0xf0, 0xf0, 0x0f, 0x0f, 0xf0, 0xf0, 0x0f, 0x0f];
let mut crsr = std::io::Cursor::new(vec);
let r = crsr.read_and_decode_vu64();
assert!(r.is_ok());
assert_eq!(r.unwrap(), 0x0f0f_f0f0_0f0f_f0f0);
Encode and write to buffer
use vu64::io::WriteVu64;
let vec_0: Vec<u8> = vec![0xFF, 0xf0, 0xf0, 0x0f, 0x0f, 0xf0, 0xf0, 0x0f, 0x0f];
let vec: Vec<u8> = Vec::new();
let mut crsr = std::io::Cursor::new(vec);
let r = crsr.encode_and_write_vu64(0x0f0f_f0f0_0f0f_f0f0);
assert!(r.is_ok());
assert_eq!(crsr.get_ref().as_slice(), vec_0.as_slice());
Changelogs
References
License
This project is licensed under either of
- Apache License, Version 2.0, (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)
at your option.