From fff3bce92dce1501846a3f8ee6b350375ed22c58 Mon Sep 17 00:00:00 2001 From: Kim Alvefur Date: Mon, 12 Jan 2015 15:10:37 +0100 Subject: util.hex: Pedantic optimization, 1 table lookup per byte instead of 3 function calls makes it go faster --- util/hex.lua | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) (limited to 'util/hex.lua') diff --git a/util/hex.lua b/util/hex.lua index b21ee17e..e41f4863 100644 --- a/util/hex.lua +++ b/util/hex.lua @@ -1,19 +1,25 @@ local s_char = string.char; +local s_format = string.format; +local s_gsub = string.gsub; -local function char_to_hex(c) - return ("%02x"):format(c:byte()) -end +local char_to_hex = {}; +local hex_to_char = {}; -local function hex_to_char(h) - return s_char(tonumber(h, 16)); +do + local char, hex; + for i = 0,255 do + char, hex = s_char(i), s_format("%02x", i); + char_to_hex[char] = hex; + hex_to_char[hex] = char; + end end local function to(s) - return s:gsub(".", char_to_hex); + return (s_gsub(s, ".", char_to_hex)); end local function from(s) - return s:gsub("..", hex_to_char); + return (s_gsub(s, "..", hex_to_char)); end return { to = to, from = from } -- cgit v1.2.3