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prosody
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util/queue.lua @ 9196:2fc56434c6e3
mod_pep: Remove already included access model feature
access-* is added in pubsub.lib based on node defaults
author | Kim Alvefur <zash@zash.se> |
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date | Sat, 18 Aug 2018 14:29:13 +0200 |
parent | 6912:cb5b14c95b7b |
child | 9901:c8b75239846c |
child | 11103:73b8aaf55775 |
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-- Prosody IM -- Copyright (C) 2008-2015 Matthew Wild -- Copyright (C) 2008-2015 Waqas Hussain -- -- This project is MIT/X11 licensed. Please see the -- COPYING file in the source package for more information. -- -- Small ringbuffer library (i.e. an efficient FIFO queue with a size limit) -- (because unbounded dynamically-growing queues are a bad thing...) local have_utable, utable = pcall(require, "util.table"); -- For pre-allocation of table local function new(size, allow_wrapping) -- Head is next insert, tail is next read local head, tail = 1, 1; local items = 0; -- Number of stored items local t = have_utable and utable.create(size, 0) or {}; -- Table to hold items --luacheck: ignore 212/self return { _items = t; size = size; count = function (self) return items; end; push = function (self, item) if items >= size then if allow_wrapping then tail = (tail%size)+1; -- Advance to next oldest item items = items - 1; else return nil, "queue full"; end end t[head] = item; items = items + 1; head = (head%size)+1; return true; end; pop = function (self) if items == 0 then return nil; end local item; item, t[tail] = t[tail], 0; tail = (tail%size)+1; items = items - 1; return item; end; peek = function (self) if items == 0 then return nil; end return t[tail]; end; items = function (self) --luacheck: ignore 431/t return function (t, pos) if pos >= t:count() then return nil; end local read_pos = tail + pos; if read_pos > t.size then read_pos = (read_pos%size); end return pos+1, t._items[read_pos]; end, self, 0; end; }; end return { new = new; };