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prosody
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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> |
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date | Tue, 11 May 2021 02:09:56 +0200 |
parent | 11116:d334f2bebe55 |
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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);