Daniel Lemire

Optimize format for short bitmaps or sparse data

8

Bitmaps spanning a small space (far less than 2^16 bits) are not necessarily optimally supported right now by Roaring. This could be improved. If people store only a handful of...

Equality between run containers and other containers (e.g. bitmap) is checked in an inefficient manner currently

1

The code could be much faster.

Implements equals between RoaringBitmap and ImmutableRoaringBitmap instances

2

Currently, a RoaringBitmap and an ImmutableRoaringBitmap are always different, even when they have the same content.

Optimize "equals"

1

To Go version of Roaring has some interesting optimizations regarding the "equals" function that could be ported to Java: https://github.com/bpot/roaring/commit/8d4e6a48b085abebfa7cf81ffdce5c3f5d782124

The semantics of equality between container is based on the content stored in the container. If two containers have the same content (as a set of integers), even if they...

Add support for run containers

14

As of version 0.5, the java version of Roaring bitmaps supports run containers... https://github.com/lemire/RoaringBitmap/blob/master/src/main/java/org/roaringbitmap/RunContainer.java These can be created by the "runOptimize" function... https://github.com/lemire/RoaringBitmap/blob/master/src/main/java/org/roaringbitmap/RoaringBitmap.java#L1286 These containers can improve the compression ratio...

In some cases, the andNot function can cause fragmentation: the insertion of zero literal words inside the bitmap. One can produce it with the following code: ```Java EWAHCompressedBitmap one =...

Port SIMD code to ARM NEON

1

Initially, SIMD code supports only x64 processors, but it should be simple to add support for ARM NEON as well.

In C#... ```C# System.Buffers.Text.Utf8Parser.TryParse(x, out double d, out int consumed) ``` will *not* skip leading spaces whereas ```C# Double.Parse(" 11 ") ``` will... Meanwhile, the csFastFloat functions *always* skip leading...

Microsoft launched a package manager that should be supported by this library... https://github.com/Microsoft/vcpkg