github.com/lbryio/lbcd@v0.22.119/database/internal/treap/doc.go (about)

     1  // Copyright (c) 2015-2016 The btcsuite developers
     2  // Use of this source code is governed by an ISC
     3  // license that can be found in the LICENSE file.
     4  
     5  /*
     6  Package treap implements a treap data structure that is used to hold ordered
     7  key/value pairs using a combination of binary search tree and heap semantics.
     8  It is a self-organizing and randomized data structure that doesn't require
     9  complex operations to to maintain balance.  Search, insert, and delete
    10  operations are all O(log n).  Both mutable and immutable variants are provided.
    11  
    12  The mutable variant is typically faster since it is able to simply update the
    13  treap when modifications are made.  However, a mutable treap is not safe for
    14  concurrent access without careful use of locking by the caller and care must be
    15  taken when iterating since it can change out from under the iterator.
    16  
    17  The immutable variant works by creating a new version of the treap for all
    18  mutations by replacing modified nodes with new nodes that have updated values
    19  while sharing all unmodified nodes with the previous version.  This is extremely
    20  useful in concurrent applications since the caller only has to atomically
    21  replace the treap pointer with the newly returned version after performing any
    22  mutations.  All readers can simply use their existing pointer as a snapshot
    23  since the treap it points to is immutable.  This effectively provides O(1)
    24  snapshot capability with efficient memory usage characteristics since the old
    25  nodes only remain allocated until there are no longer any references to them.
    26  */
    27  package treap