limit certain nodes to individual max

Some nodes have cpu intensive side-effects when placed.
To avoid lag, this commit adds mechanism to limit per node.

init.lua

@@ -52,6 +52,10 @@ local path = minetest.get_modpath("replacer")
 
 replacer = {}
 
+-- limit by node, use replacer.register_limit(sName, iMax)
+replacer.limit_list = {}
+
+-- don't allow these at all
 replacer.blacklist = {}
 
 -- playing with tnt and creative building are usually contradictory

replacer.lua

@@ -28,6 +28,33 @@ replacer.mode_colours[r.modes[2]] = "#54FFAC"
 replacer.mode_colours[r.modes[3]] = "#9F6200"
 replacer.mode_colours[r.modes[4]] = "#FF5457"
 
+local is_int = function(value)
+	return type(value) == 'number' and math.floor(value) == value
+end
+
+function replacer.register_limit(node_name, node_max)
+	-- ignore nil and negative numbers
+	if (nil == node_max) or (0 > node_max) then
+		return
+	end
+	-- ignore non-integers
+	if not is_int(node_max) then
+		return
+	end
+	-- add to blacklist if limit is zero
+	if 0 == node_max then
+		replacer.blacklist[node_name] = true
+		minetest.log("info", rb.blacklist_insert:format(node_name))
+		return
+	end
+	-- log info if already limited
+	if nil ~= r.limit_list[node_name] then
+		minetest.log("info", rb.limit_override:format(node_name, r.limit_list[node_name]))
+	end
+	r.limit_list[node_name] = node_max
+	minetest.log("info", rb.limit_insert:format(node_name, node_max))
+end
+
 function replacer.get_data(stack)
 	local metaRef = stack:get_meta()
 	local data = metaRef:get_string("replacer"):split(" ") or {}
@@ -257,7 +284,7 @@ function replacer.replace(itemstack, user, pt, right_clicked)
 		return
 	end
 
-	local max_nodes = replacer.max_nodes
+	local max_nodes = r.limit_list[nnd.name] or r.max_nodes
 	local charge
 	if replacer.has_technic_mod and (not (creative_enabled or has_give)) then
 		charge = r.get_charge(itemstack)

replacer_blabla.lua

@@ -26,4 +26,7 @@ replacer.blabla.not_in_inventory = 'Item not in your inventory: "%s".'
 replacer.blabla.set_to = 'Node replacement tool set to: "%s".'
 replacer.blabla.description_basic = "Node replacement tool"
 replacer.blabla.description_technic = "Node replacement tool (technic)"
+replacer.blabla.limit_override = 'Setting already set node-limit for "%s" was %d.'
+replacer.blabla.limit_insert = 'Setting node-limit for "%s" to %d.'
+replacer.blabla.blacklist_insert = 'Blacklisted "%s".'