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prosody
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util/array.lua @ 12172:2515033c2a74
mod_bookmarks: Skip migration of legacy data when empty
Should save some cycles and not log the debug message on every login.
author | Kim Alvefur <zash@zash.se> |
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date | Mon, 10 Jan 2022 00:13:17 +0100 |
parent | 11787:3ae6fa901a8b |
child | 12403:42b2713ab818 |
child | 13138:0b0cefce6e42 |
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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. -- local t_insert, t_sort, t_remove, t_concat = table.insert, table.sort, table.remove, table.concat; local setmetatable = setmetatable; local getmetatable = getmetatable; local math_random = math.random; local math_floor = math.floor; local pairs, ipairs = pairs, ipairs; local tostring = tostring; local type = type; local array = {}; local array_base = {}; local array_methods = {}; local array_mt = { __index = array_methods; __name = "array"; __tostring = function (self) return "{"..self:concat(", ").."}"; end; }; function array_mt:__freeze() return self; end local function new_array(self, t, _s, _var) if type(t) == "function" then -- Assume iterator t = self.collect(t, _s, _var); end return setmetatable(t or {}, array_mt); end function array_mt.__add(a1, a2) local res = new_array(); return res:append(a1):append(a2); end function array_mt.__eq(a, b) if getmetatable(a) ~= array_mt or getmetatable(b) ~= array_mt then -- Lua 5.3+ calls this if both operands are tables, even if metatables differ return false; end if #a == #b then for i = 1, #a do if a[i] ~= b[i] then return false; end end else return false; end return true; end function array_mt.__div(a1, func) local a2 = new_array(); local o = 0; for i = 1, #a1 do local new_value = func(a1[i]); if new_value ~= nil then o = o + 1; a2[o] = new_value; end end return a2; end setmetatable(array, { __call = new_array }); -- Read-only methods function array_methods:random() return self[math_random(1, #self)]; end -- Return a random value excluding the one at idx function array_methods:random_other(idx) local max = #self; return self[((math.random(1, max-1)+(idx-1))%max)+1]; end -- These methods can be called two ways: -- array.method(existing_array, [params [, ...]]) -- Create new array for result -- existing_array:method([params, ...]) -- Transform existing array into result -- function array_base.map(outa, ina, func) for k, v in ipairs(ina) do outa[k] = func(v); end return outa; end function array_base.filter(outa, ina, func) local inplace, start_length = ina == outa, #ina; local write = 1; for read = 1, start_length do local v = ina[read]; if func(v) then outa[write] = v; write = write + 1; end end if inplace and write <= start_length then for i = write, start_length do outa[i] = nil; end end return outa; end function array_base.slice(outa, ina, i, j) if j == nil then j = -1; end if j < 0 then j = #ina + (j+1); end if i < 0 then i = #ina + (i+1); end if i < 1 then i = 1; end if j > #ina then j = #ina; end if i > j then for idx = 1, #outa do outa[idx] = nil; end return outa; end for idx = 1, 1+j-i do outa[idx] = ina[i+(idx-1)]; end if ina == outa then for idx = 2+j-i, #outa do outa[idx] = nil; end end return outa; end function array_base.sort(outa, ina, ...) if ina ~= outa then outa:append(ina); end t_sort(outa, ...); return outa; end function array_base.unique(outa, ina) local seen = {}; return array_base.filter(outa, ina, function (item) if seen[item] then return false; else seen[item] = true; return true; end end); end function array_base.pluck(outa, ina, key, default) for i = 1, #ina do local v = ina[i][key]; if v == nil then v = default; end outa[i] = v; end return outa; end function array_base.reverse(outa, ina) local len = #ina; if ina == outa then local middle = math_floor(len/2); len = len + 1; local o; -- opposite for i = 1, middle do o = len - i; outa[i], outa[o] = outa[o], outa[i]; end else local off = len + 1; for i = 1, len do outa[i] = ina[off - i]; end end return outa; end --- These methods only mutate the array function array_methods:shuffle() local len = #self; for i = 1, #self do local r = math_random(i, len); self[i], self[r] = self[r], self[i]; end return self; end function array_methods:append(ina) local len, len2 = #self, #ina; for i = 1, len2 do self[len+i] = ina[i]; end return self; end function array_methods:push(x) t_insert(self, x); return self; end array_methods.pop = t_remove; function array_methods:concat(sep) return t_concat(array.map(self, tostring), sep); end function array_methods:length() return #self; end --- These methods always create a new array function array.collect(f, s, var) local t = {}; while true do var = f(s, var); if var == nil then break; end t_insert(t, var); end return setmetatable(t, array_mt); end --- -- Setup methods from array_base for method, f in pairs(array_base) do local base_method = f; -- Setup global array method which makes new array array[method] = function (old_a, ...) local a = new_array(); return base_method(a, old_a, ...); end -- Setup per-array (mutating) method array_methods[method] = function (self, ...) return base_method(self, self, ...); end end return array;