X-Git-Url: https://git.enpas.org/?a=blobdiff_plain;f=util%2Farray.lua;h=b10396b105e4613e329bcd621680ccfe2601a879;hb=49f770653e6d1076c0cf4b8ebc6a578976baf321;hp=9e99a3ec2a1238550b0aa48d5b2bad792ef2e313;hpb=cadc7a50b10f6e70e8cd3e3141cc266bad453d6f;p=prosody.git

diff --git a/util/array.lua b/util/array.lua
index 9e99a3ec..b10396b1 100644
--- a/util/array.lua
+++ b/util/array.lua
@@ -1,55 +1,175 @@
+-- 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 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, __tostring = function (array) return "{"..array:concat(", ").."}"; end };
 
-local array_mt = { __index = array, __tostring = function (array) return array:concat(", "); end };
-local function new_array(_, t)
+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
+
 setmetatable(array, { __call = new_array });
 
-function array:map(func, t2)
-	local t2 = t2 or array{};
-	for k,v in ipairs(self) do
-		t2[k] = func(v);
+-- Read-only methods
+function array_methods:random()
+	return self[math_random(1,#self)];
+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 t2;
+	return outa;
 end
 
-function array:filter(func, t2)
-	local t2 = t2 or array{};
-	for k,v in ipairs(self) do
+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
-			t2:push(v);
+			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 t2;
+
+	return outa;
 end
 
+function array_base.sort(outa, ina, ...)
+	if ina ~= outa then
+		outa:append(ina);
+	end
+	t_sort(outa, ...);
+	return outa;
+end
 
-array.push = table.insert;
-array.pop = table.remove;
-array.sort = table.sort;
-array.concat = table.concat;
-array.length = function (t) return #t; end
+function array_base.pluck(outa, ina, key)
+	for i=1,#ina do
+		outa[i] = ina[i][key];
+	end
+	return outa;
+end
 
-function array:random()
-	return self[math.random(1,#self)];
+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
 
-function array:shuffle()
+--- These methods only mutate the array
+function array_methods:shuffle(outa, ina)
 	local len = #self;
 	for i=1,#self do
-		local r = math.random(i,len);
+		local r = math_random(i,len);
 		self[i], self[r] = self[r], self[i];
 	end
+	return self;
+end
+
+function array_methods:append(array)
+	local len,len2  = #self, #array;
+	for i=1,len2 do
+		self[len+i] = array[i];
+	end
+	return self;
+end
+
+function array_methods:push(x)
+	t_insert(self, x);
+	return self;
+end
+
+function array_methods:pop(x)
+	local v = self[x];
+	t_remove(self, x);
+	return v;
+end
+
+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
 
-function array:reverse()
-	local len = #self-1;
-	for i=len,1,-1 do
-		self:push(self[i]);
-		self:pop(i);
+---
+
+-- 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
 
-_G.array = array 
+_G.array = array;
+module("array");
+
+return array;