Software /
code /
prosody
File
util/iterators.lua @ 5915:e6fed1d80116
Back out 1b0ac7950129, as SSLv3 appears to still be in moderate use on the network. Also, although obsolete, SSLv3 isn't documented to have any weaknesses that TLS 1.0 (the most common version used today) doesn't also have. Get your act together clients!
author | Matthew Wild <mwild1@gmail.com> |
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date | Tue, 12 Nov 2013 02:13:01 +0000 |
parent | 5468:2660407c3b73 |
child | 5581:167c1da54606 |
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-- Prosody IM -- Copyright (C) 2008-2010 Matthew Wild -- Copyright (C) 2008-2010 Waqas Hussain -- -- This project is MIT/X11 licensed. Please see the -- COPYING file in the source package for more information. -- --[[ Iterators ]]-- local it = {}; -- Reverse an iterator function it.reverse(f, s, var) local results = {}; -- First call the normal iterator while true do local ret = { f(s, var) }; var = ret[1]; if var == nil then break; end table.insert(results, 1, ret); end -- Then return our reverse one local i,max = 0, #results; return function (results) if i<max then i = i + 1; return unpack(results[i]); end end, results; end -- Iterate only over keys in a table local function _keys_it(t, key) return (next(t, key)); end function it.keys(t) return _keys_it, t; end -- Iterate only over values in a table function it.values(t) local key, val; return function (t) key, val = next(t, key); return val; end, t; end -- Given an iterator, iterate only over unique items function it.unique(f, s, var) local set = {}; return function () while true do local ret = { f(s, var) }; var = ret[1]; if var == nil then break; end if not set[var] then set[var] = true; return var; end end end; end --[[ Return the number of items an iterator returns ]]-- function it.count(f, s, var) local x = 0; while true do local ret = { f(s, var) }; var = ret[1]; if var == nil then break; end x = x + 1; end return x; end -- Return the first n items an iterator returns function it.head(n, f, s, var) local c = 0; return function (s, var) if c >= n then return nil; end c = c + 1; return f(s, var); end, s; end -- Skip the first n items an iterator returns function it.skip(n, f, s, var) for i=1,n do var = f(s, var); end return f, s, var; end -- Return the last n items an iterator returns function it.tail(n, f, s, var) local results, count = {}, 0; while true do local ret = { f(s, var) }; var = ret[1]; if var == nil then break; end results[(count%n)+1] = ret; count = count + 1; end if n > count then n = count; end local pos = 0; return function () pos = pos + 1; if pos > n then return nil; end return unpack(results[((count-1+pos)%n)+1]); end --return reverse(head(n, reverse(f, s, var))); end local function _ripairs_iter(t, key) if key > 1 then return key-1, t[key-1]; end end function it.ripairs(t) return _ripairs_iter, t, #t+1; end local function _range_iter(max, curr) if curr < max then return curr + 1; end end function it.range(x, y) if not y then x, y = 1, x; end -- Default to 1..x if y not given return _range_iter, y, x-1; end -- Convert the values returned by an iterator to an array function it.to_array(f, s, var) local t, var = {}; while true do var = f(s, var); if var == nil then break; end table.insert(t, var); end return t; end -- Treat the return of an iterator as key,value pairs, -- and build a table function it.to_table(f, s, var) local t, var2 = {}; while true do var, var2 = f(s, var); if var == nil then break; end t[var] = var2; end return t; end return it;