Crate inline_array

InlineArray is an inlinable array of bytes that is intended for situations where many bytes are being shared in database-like scenarios, where optimizing for space usage is extremely important.

InlineArray uses 8 bytes on the stack. It will inline arrays of up to 7 bytes. If the bytes are longer than that, it will store them in an optimized reference-count-backed structure, where the atomic reference count is 16 bytes. If the maximum counter is reached, the bytes are copied into a new InlineArray with a fresh reference count of 1. This is made with the assumption that most reference counts will be far lower than 2^16.

Both the inline and shared instances of InlineArray guarantee that the stored array is always aligned to 8-byte boundaries, regardless of if it is inline on the stack or shared on the heap. This is advantageous for using in combination with certain zero-copy serialization techniques.

The 16-bit reference counter is stored packed with a 48-bit length field at the beginning of the shared array. Byte arrays that require more than 48 bits to store their length (256 terabytes) are not supported.

InlineArray::make_mut can be used for getting a mutable reference to the bytes in this structure. If the shared reference counter is higher than 1, this acts like a Cow and will make self into a private copy that is safe for modification.

Structs

• InlineArray
  A buffer that may either be inline or remote and protected by an Arc. The inner buffer is guaranteed to be aligned to 8 byte boundaries.