VoxeLibre/mods/ITEMS/mcl_enchanting/efficiency.lua
Elias Åström 6458565bf9 Move mcl_util.hash to a local function
It is probably unlikely it will be useful at other places in Mineclone2.
2021-03-18 11:35:40 +01:00

54 lines
2 KiB
Lua

local efficiency_cache_table = {}
-- Compute a hash value.
function compute_hash(value)
-- minetest.get_password_hash is quite fast, even if it uses a
-- cryptographic hashing function (SHA-1). It is written in C++ and it
-- is probably hard to write a faster hashing function in Lua.
return string.sub(minetest.get_password_hash("ryvnf", minetest.serialize(value)), 1, 8)
end
-- Get the efficiency groupcaps and hash for a tool and efficiency level. If
-- this function is called repeatedly with the same values it will return data
-- from a cache.
--
-- Returns a table with the following two fields:
-- values - the groupcaps table
-- hash - the hash of the groupcaps table
local function get_efficiency_groupcaps(toolname, level)
local toolcache = efficiency_cache_table[toolname]
if not toolcache then
toolcache = {}
efficiency_cache_table[toolname] = toolcache
end
local levelcache = toolcache[level]
if not levelcache then
levelcache = {}
levelcache.values = mcl_autogroup.get_groupcaps(toolname, level)
levelcache.hash = compute_hash(levelcache.values)
toolcache[level] = levelcache
end
return levelcache
end
-- Apply efficiency enchantment to a tool. This will update the tools
-- tool_capabilities to give it new digging times. This function will be called
-- repeatedly to make sure the digging times stored in groupcaps stays in sync
-- when the digging times of nodes can change.
--
-- To make it more efficient it will first check a hash value to determine if
-- the tool needs to be updated.
function mcl_enchanting.apply_efficiency(itemstack, level)
local name = itemstack:get_name()
local groupcaps = get_efficiency_groupcaps(name, level)
local hash = itemstack:get_meta():get_string("groupcaps_hash")
if not hash or hash ~= groupcaps.hash then
local tool_capabilities = itemstack:get_tool_capabilities()
tool_capabilities.groupcaps = groupcaps.values
itemstack:get_meta():set_tool_capabilities(tool_capabilities)
itemstack:get_meta():set_string("groupcaps_hash", groupcaps.hash)
end
end