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The same functionallityis available in stable Rust since 1.53, use that instead

THE fastest way to implement any kind of decoding forRunLengthEncoded data in Rust.

Writing a fast decoder that is also safe can be quite challenging, so this crate is here to save you thehassle of maintaining and testing your own implementation.

Of course, you need to depend on this crate:

rle-decode-fast ="1.0"

There is only a single function to use,rle_decode<T>(&mut Vec<T>, lookbehind_size: usize, fill_length: usize).It takes :

• a vector to modify,
• the number of items to copy from said vector (basicallyvector[(vector.len() - lookbehind)..])
• the number of items to append.Afterwards the vector will contain an extrafill_length items.

use rle_decode_fast::rle_decode;letmut decode_buffer =vec![0,0,1,1,0,2,3];let lookbehind_length =4;let output_length =10;rle_decode(&mut decode_buffer, lookbehind_length, output_length);assert_eq!(decode_buffer,[0,0,1,1,0,2,3,1,0,2,3,1,0,2,3,1,0]);

There are cases where the decode functions panics

• The lookbehind length is 0
• The lookbehind length is bigger than the Vec's length
• The output length + Vec's length would overflow

The idea for this crate first originated fromthis pre-RFC.It brought to attention a weak-point in the standard library, which lead some crates writing their own unsafe by-pass.

During the exploration happening in the pre-RFC, some experimentation was conducted. For examples seehere andhere.

There is a benchmark comparing a naive (repeated push) implementation, a vulnerable implementation that might lead touninitialized memory and this crate.

The results for a very small fill lengthand for a bigger fill lengths

Licensed under either of

• Apache License, Version 2.0LICENSE-APACHE
• MIT licenseLICENSE-MIT

at your option.

Unless you explicitly state otherwise, any contribution intentionally submittedfor inclusion in the work by you, as defined in the Apache-2.0 license, shall bedual licensed as above, without any additional terms or conditions.