From eaf38e4e0381c2e02e75731528825572929fac0c Mon Sep 17 00:00:00 2001
From: DS-Minetest <vorunbekannt75@web.de>
Date: Sat, 3 Jun 2017 12:05:32 +0200
Subject: [PATCH] add filter

---
 README.md |   6 ++-
 init.lua  | 122 +++++++++++++++++++++++++++++++++++++++++++++---------
 2 files changed, 107 insertions(+), 21 deletions(-)

diff --git a/README.md b/README.md
index 55043c8..76801eb 100644
--- a/README.md
+++ b/README.md
@@ -3,12 +3,14 @@
 ### This mod is client- and server-side.
 
 ### Added functions are:
-- `keyevent.register_on_keypress_bits(func(keys, old_keys, dtime, player_name))`
+- `keyevent.register_on_keypress_bits([keys_to_be_pressed, ]func(keys, old_keys, dtime, player_name))`
+  - `keys_to_be_pressed`: Optional. It can be a string, a table or a number.
+  If any of these keys is changed, the event is triggered
   - `keys`: The pressed keys in bit format.
   - `old_keys`: The keys pressed before.
   - `dtime`: Time from last check.
   - `player_name`: Name of the player. Client-side this is `nil`.
 
-- `keyevent.register_on_keypress(func(keys, old_keys, dtime, player_name))`
+- `keyevent.register_on_keypress([keys_to_be_pressed, ]func(keys, old_keys, dtime, player_name))`
   - Same as above but `keys` and `old_keys` is given in table format.
 
diff --git a/init.lua b/init.lua
index 453ddf3..0b3aadc 100644
--- a/init.lua
+++ b/init.lua
@@ -11,27 +11,18 @@ local load_time_start = os.clock()
 local modname = minetest.get_current_modname()
 
 
-keyevent = {}
-local keyevents_bits = {}
-function keyevent.register_on_keypress_bits(func)
-	keyevents_bits[#keyevents_bits+1] = func
-end
-local keyevents = {}
-function keyevent.register_on_keypress(func)
-	keyevents[#keyevents+1] = func
-end
+local meaning = {
+	[0] = "up", "down", "left",
+	"right", "jump", "aux1",
+	"sneak", "LMB", "RMB"
+}
 
 local function bits_to_table(bits)
 	if type(bits) ~= "number" then
 		return bits
 	end
-	local meaning = {
-		[0] = "up", "down", "left",
-		"right", "jump", "aux1",
-		"sneak", "LMB", "RMB"
-	}
 	local t = {}
-	for i = 8, 0, -1 do
+	for i = #meaning, 0, -1 do
 		local n = 2^i
 		if bits >= n then
 			bits = bits - n
@@ -43,17 +34,110 @@ local function bits_to_table(bits)
 	return t
 end
 
+local function table_to_bits(t)
+	if type(t) ~= "table" then
+		return t
+	end
+	local bits = 0
+	for i = 0, #meaning do
+		if t[meaning[i]] then
+			bits = bits + 2^i
+		end
+	end
+	return bits
+end
+
+local function make_true(t)
+	local out = {}
+	for i = 1, #t do
+		out[t[i]] = true
+	end
+	for i = 0, #meaning do
+		out[meaning[i]] = out[meaning[i]] or false
+	end
+	return out
+end
+
+local function look_differences(bitsa, bitsb)
+	if not bitsb then
+		return 511
+	end
+	local diff = 0
+	for i = #meaning, 0, -1 do
+		local n = 2^i
+		local a = bitsa - n >= 0
+		local b = bitsb - n >= 0
+		if a ~= b  then
+			diff = diff + n
+		end
+		bitsa = bitsa - ((a and n) or 0)
+		bitsb = bitsb - ((b and n) or 0)
+	end
+	return diff
+end
+
+local function is_different(diff_shall, diff_is)
+	for i = #meaning, 0, -1 do
+		local n = 2^i
+		local a = diff_shall - n >= 0
+		local b = diff_is - n >= 0
+		if a and b then
+			return true
+		end
+		diff_shall = diff_shall - ((a and n) or 0)
+		diff_is = diff_is - ((b and n) or 0)
+	end
+	return false
+end
+
+local function handle_keys(keys, func)
+	local keyst = type(keys)
+	if keyst == "function" then
+		func = keys
+		keys = 511
+	elseif keyst == "string" then
+		for i = 0, #meaning do
+			if keys == meaning[i] then
+				keys = 2^i
+				break
+			end
+		end
+	elseif keyst == "table" then
+		keys = table_to_bits((#keys >= 1 and make_true(keys)) or keys)
+	elseif keyst ~= "number" then
+		keys = 511
+	end
+	return keys, func
+end
+
+keyevent = {}
+local keyevents_bits = {}
+function keyevent.register_on_keypress_bits(keys, func)
+	keys, func = handle_keys(keys, func)
+	keyevents_bits[keys] = func
+end
+local keyevents = {}
+function keyevent.register_on_keypress(func)
+	keys, func = handle_keys(keys, func)
+	keyevents[keys] = func
+end
+
 local function on_step(dtime, player, old_keys, keys, player_name)
 	if keys == old_keys then
 		return
 	end
-	for i = 1, #keyevents_bits do
-		keyevents_bits[i](keys, old_keys, dtime, player_name)
+	local diff = look_differences(keys, old_keys)
+	for diff_shall, f in pairs(keyevents_bits) do
+		if is_different(diff_shall, diff) then
+			f(keys, old_keys, dtime, player_name)
+		end
 	end
 	local keys_t = bits_to_table(keys)
 	local old_keys_t = bits_to_table(old_keys)
-	for i = 1, #keyevents do
-		keyevents[i](keys_t, old_keys_t, dtime, player_name)
+	for diff_shall, f in pairs(keyevents) do
+		if is_different(diff_shall, diff) then
+			f(keys_t, old_keys_t, dtime, player_name)
+		end
 	end
 	return keys
 end