File

spec/util_indexedbheap_spec.lua @ 13134:638f627e707f

util.datamanager: Add O(1) list indexing with on-disk index Index file contains offsets and lengths of each item() which allows seeking directly to each item and reading it without parsing the entire file. Also allows tricks like binary search, assuming items have some defined order. We take advantage of the 1-based indexing in tables to store a magic header in the 0 position, so that table index 1 ends up at file index 1.
author Kim Alvefur <zash@zash.se>
date Tue, 11 May 2021 02:09:56 +0200
parent 11116:d334f2bebe55
line wrap: on
line source

local ibh = require"util.indexedbheap";

local function verify_heap_property(priorities)
	for k in ipairs(priorities) do
		local parent = priorities[k];
		local childA = priorities[2*k];
		local childB = priorities[2*k+1];
		-- print("-", parent, childA, childB)
		assert(childA == nil or childA > parent, "heap property violated");
		assert(childB == nil or childB > parent, "heap property violated");
	end
end

local h
setup(function ()
	h = ibh.create();
end)
describe("util.indexedbheap", function ()
	it("item can be moved from end to top", function ()
		verify_heap_property(h);
		h:insert("a", 1);
		verify_heap_property(h);
		h:insert("b", 2);
		verify_heap_property(h);
		h:insert("c", 3);
		verify_heap_property(h);
		local id = h:insert("*", 10);
		verify_heap_property(h);
		h:reprioritize(id, 0);
		verify_heap_property(h);
		assert.same({ 0, "*", id }, { h:pop() });
	end)
end);