local string = string
local sfind = string.find
local slen = string.len
local ssub = string.sub
local sgub = string.gsub
local sformat = string.format
local setmetatable = setmetatable
local tinsert = table.insert

string.split1 = function (szFullString, szSeparator)
	local nFindStartIndex = 1
	local nSplitIndex = 1
	local nSplitArray = {}
	while true do
	   local nFindLastIndex = string.find(szFullString, szSeparator, nFindStartIndex)
	   if not nFindLastIndex then
			nSplitArray[nSplitIndex] = string.sub(szFullString, nFindStartIndex, string.len(szFullString))
			break
	   end
	   nSplitArray[nSplitIndex] = string.sub(szFullString, nFindStartIndex, nFindLastIndex - 1)
	   nFindStartIndex = nFindLastIndex + string.len(szSeparator)
	   nSplitIndex = nSplitIndex + 1
	end
	return nSplitArray
end


function string.split2(szFullString, szSeparator)
	local nFindStartIndex = 1
	local nSplitIndex = 1
	local nSplitArray = {}
	while true do
	   local nFindLastIndex = sfind(szFullString, szSeparator, nFindStartIndex)
	   if not nFindLastIndex then
			nSplitArray[nSplitIndex] = ssub(szFullString, nFindStartIndex,  slen(szFullString))
			break
	   end
	   nSplitArray[nSplitIndex] = ssub(szFullString, nFindStartIndex, nFindLastIndex - 1)
	   nFindStartIndex = nFindLastIndex + 1
	   nSplitIndex = nSplitIndex + 1
	end
	return nSplitArray
end

function string.split3(str, sep)
  local parts = {__index = tinsert}
  setmetatable(parts, parts)
  sgub(str, sformat("([^%s]+)", sep), parts)
  setmetatable(parts, nil)
  parts.__index = nil
  return parts
end

function string.split4(str, sep)
	local ary = {}
	sgub(str, sformat("([^%s]+)", sep), function(c) ary[#ary+1] = c end)
	return ary
end

function string.split6(str, mark)
	mark = mark or ",";
	local setStr = {};
	local marklen = string.len(mark);
	local slength = string.len(str);
	local index = 0
	local start = 1
	while true do
	    index = string.find(str, mark, start)   -- find 'next' 返回 i 和 j 
	    if index == nil then break end
		local s = string.sub(str, start, index-1)
	    table.insert(setStr, s)
		start = index + marklen;
	end
	if start <= slength then
		local s = string.sub(str, start, slength)
	    table.insert(setStr, s)
	end
	return setStr;
end


local s_ary = {}
local s_i = 1
local function func(c)
	s_ary[s_i] = c
	s_i = s_i + 1
end
function string.split5(str, sep)
	s_ary = {}
	s_i = 1
	sgub(str, sformat("([^%s]+)", sep), func)
	return s_ary
end



local s = "1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20"

local t = os.clock()
for i = 1, 100000 do
	local x = string.split1(s, "+")
end
print("string.split: " ,os.clock() - t)

t = os.clock()
for i = 1, 100000 do
	local x = string.split2(s, "+")
end
print("string.split2: " , os.clock() - t)

t = os.clock()
for i = 1, 100000 do
	local x = string.split3(s, "+")
end
print("string.split3: " , os.clock() - t)

t = os.clock()
for i = 1, 100000 do
	local x = string.split4(s, "+")
end
print("string.split4: " , os.clock() - t)

t = os.clock()
for i = 1, 100000 do
	local x = string.split5(s, "+")
end
print("string.split5: " , os.clock() - t)

t = os.clock()
for i = 1, 100000 do
	local x = string.split6(s, "+")
end
print("string.split6: " , os.clock() - t)

os.execute("PAUSE")