minetest-australopithecus-utils/utils/tableutil.lua

--[[
Copyright (c) 2014, Robert 'Bobby' Zenz
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--]]


--- Various utility functions for working with tables.
tableutil = {}


--- Performs a deep/recursive clone on the given table.
--
-- @param table The table to deep clone.
-- @return The clone of the table.
function tableutil.clone(table)
	if table == nil then
		return nil
	end
	
	if type(table) ~= "table" then
		local clone = table
		return clone
	end
	
	local clone = {}
	
	for key, value in next, table, nil do
		if value ~= table then
			clone[tableutil.clone(key)] = tableutil.clone(value)
		else
			clone[tableutil.clone(key)] = clone
		end
	end
	
	setmetatable(clone, tableutil.clone(getmetatable(table)))
	
	return clone
end

--- Merges the given tables into one instance. Note that no cloning is performed
-- so fields may refer to the same instances.
--
-- @param ... The tables to merge.
-- @return The merged table.
function tableutil.merge(...)
	if ... == nil then
		return nil
	end
	
	local merged = {}
	
	for index, table in ipairs({...}) do
		for key, value in next, table, nil do
			merged[key] = value
		end
	end
	
	return merged
end

--- Reindexes the given 2d array/table, swapping the two dimensions.
--
-- @param data The array/table to reindex.
-- @param new_x The new startpoint for the first dimension.
-- @param new_y The new startpoint for the second dimension.
-- @return The reindexed data.
function tableutil.swapped_reindex2d(data, new_x, new_y)
	local reindexed_data = {}
	
	for old_x = 1, constants.block_size, 1 do
		local index_x = new_x + old_x - 1
		reindexed_data[index_x] = {}
		
		for old_y = 1, constants.block_size, 1 do
			local index_y = new_y + old_y - 1
				
			reindexed_data[index_x][index_y] = data[old_y][old_x]
		end
	end
	
	return reindexed_data
end

--- Reindexes the given 3d array/table, swapping the two dimensions.
--
-- @param data The array/table to reindex.
-- @param new_x The new startpoint for the first dimension.
-- @param new_y The new startpoint for the second dimension.
-- @param new_z The new startpoint for the third dimension.
-- @return The reindexed data.
function tableutil.swapped_reindex3d(data, new_x, new_y, new_z)
	local reindexed_data = {}
	
	for old_x = 1, constants.block_size, 1 do
		local index_x = new_x + old_x - 1
		reindexed_data[index_x] = {}
	
		for old_z = 1, constants.block_size, 1 do
			local index_z = new_z + old_z - 1
			reindexed_data[index_x][index_z] = {}
		
			for old_y = 1, constants.block_size, 1 do
				local index_y = new_y + old_y - 1
			
				reindexed_data[index_x][index_z][index_y] = data[old_z][old_y][old_x]
			end
		end
	end
	
	return reindexed_data
end

--- Returns the string representation of the given table.
--
-- @param table The table.
-- @param indent Optional. The number of spaces of indentation.
-- @return The string representation of the given table.
function tableutil.to_string(table, indent)
	if table == nil then
		return "nil"
	end
	
	indent = indent or 0
	
	if type(table) == "table" then
		local str = tostring(table) .. " {\n"
		
		local indentation = string.rep(" ", indent + 4)
		
		for key, value in pairs(table) do
			str = str .. indentation .. tostring(key) .. " = "
			str = str .. tableutil.to_string(value, indent + 4) .. ",\n"
		end
		
		str = string.sub(str, 0, string.len(str) - 2)
		str = str .. "\n" .. string.rep(" ", indent) .. "}"
		
		return str
	elseif type(table) == "string" then
		return "\"" .. tostring(table) .. "\""
	else
		return tostring(table)
	end
end