Feature/optimizations and cleanup.

[bilowik]

Changes

A lot of cleanup, a lot of optimizations on all fronts. Most breaking changes occur in just wrapped_sharing, basic_sharing is relatively untouched in terms of API.

General

• Removed a lot of old code that was no longer in use, including a lot of the geometry module from back before the migration to using finite field arithmetic.
• Lots of new documentation, lots of cleanup of old documentation.

Wrapped sharing

• Deprecated most of the original sharing wrapped_sharing functions
• Added new, much cleaner share/reconstruct functions.
• Added infinitely more useful, optimized, cleaner Sharer and Reconstructor structs for large files or streams, compared to the old multitude of share/reconstruct functions that sought to handle those cases.
  • Heavily inspired by sha3 hash implementation :)
• Remove old Error variants that are no longer instantiated.
  • This was missed by linters, they were only ever accessed in the Display impl but never directly instantiated anymore.

Basic sharing

• Completely remove reliance of the very inefficient matrix transposition required when sharing slices of bytes. Included a lot of cloning, a lot of Vec allocations. The benchmark improvements from this alone were ~30%, and for very large secrets >=65536 bytes, a (potentially misleading) 90% improvement.
  • The time for sharing and reconstructing now also scales very very linearly with the length of secret!
• Cleaned up a lot of unneeded allocations
• Replaced all argument instances of &[u8] and Vec<u8> with AsRef<[u8]>
• Replaced all argument instances of Vec<Vec<u8>> with U: AsRef<[u8]>, T: AsRef<[U]>
• Remove old Error variants that are no longer instantiated.
  • This was missed by linters, they were only ever accessed in the Display impl but never directly instantiated anymore.

Todo

• Look for more places where allocations can be avoided.
• Create benches for share/reconstruct and Sharer/Reconstructor Saving this for another time, issue tracking here:
  • Probably should use Cursor instead of actual File objects for Sharer/Reconstructor for consistency.