From the file header comment: * rbtree.c * implementation for PostgreSQL generic Red-Black binary tree package * Adopted from http://algolist.manual.ru/ds/rbtree.php * * This code comes from Thomas Niemann's "Sorting and Searching Algorithms: * a Cookbook". * * See http://www.cs.auckland.ac.nz/software/AlgAnim/niemann/s_man.htm for * license terms: "Source code, when part of a software project, may be used * freely without reference to the author."
The both URLs are no longer accessible. For the first one, by search for “Thomas Niemann’s Sorting and Searching Algorithms: a Cookbook”, I got https://www.epaperpress.com/sortsearch/rbt.html, but I am not sure it provides the exactly same content as the old URL. For the second one, I cannot find a replacement. Best regards, -- Chao Li (Evan) HighGo Software Co., Ltd. https://www.highgo.com/
