File

spec/util_indexedbheap_spec.lua @ 13186:affaf6d08d26

util.datamanager: Pad list writes to avoid crossing block boundaries By padding items so that they do not cross block boundaries, it becomes eaiser to delete whole blocks with fallocate() without cutting items in half, improving efficiency of such operations. Since list stores are used for message archives, where the most common deletion operation would be of the oldest entires, at the top of the file. With this, all blocks that contain items to be removed could be deleted without needing to read, delete and write out the whole file.
author Kim Alvefur <zash@zash.se>
date Wed, 07 Jun 2023 00:39:30 +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);