Module bin_layout::lencoder

Expand description

This encoding ensures that smaller integer values need fewer bytes to encode. Support types are L2 and L3.

By default, L2 (u15) is used to encode length (integer) for record. But you override it by setting L3 (u22) in features flag.

Encoding algorithm is very straightforward, reserving one or two most significant bits of the first byte to encode rest of the length.

MSB	Length	Usable Bits	Range
0	1	7	0..127
1	2	15	0..32767

MSB	Length	Usable Bits	Range
0	1	7	0..127
10	2	14	0..16383
11	3	22	0..4194303

For example, Binary representation of 0x_C0DE is 0x_11_00000011_011110

L3(0x_C0DE) is encoded in 3 bytes:

1st byte: 11_011110      # MSB is 11, so read next 2 bytes
2nd byte:        11
3rd byte:        11

Another example, L3(107) is encoded in just 1 byte:

1st byte: 0_1101011      # MSB is 0, So we don't have to read another bytes.

Re-exports

pub use L2 as Lencoder;