Cache code for performance
Cache是什么？我想来看这个贴的应该都明白，我就不Copy & Paste了。下面给出的代码可以帮助你管理Cache（当然是 wow addon lua 环境下）。
[quote]
代码中所有的 local 函数是内部实现，cache = {} 是对外接口
cache.create [color=Green]-- 创建Cache[/color]
cache.release [color=Green]-- 销毁Cache[/color]
cache.clear [color=Green]-- 清空Cache内容[/color]
cache.resize [color=Green]-- 调整Cache的大小[/color]
cache.get [color=Green]-- 从Cache获得数据[/color]
cache.set [color=Green]-- 设置Cache数据[/color]
[color=Green]-- Cache大小的预定义常量[/color]
CACHE_SIZE_ALL = -1 [color=Green]-- Cache 所有数据[/color]
CACHE_SIZE_NONE = 0 [color=Green]-- 所有数据均不Cache[/color]
CACHE_SIZE_DEF = 20 [color=Green]-- 缺省的 Cache 大小[/color]
[color=Green]-- 当Cache丢弃的数据达同时到以下的两个标准时，将进行重新索引，以节省空间[/color]
[color=Green]-- 1 当Cache丢弃的数据与有效数据之间的比例大于该Cache定义的[color=Blue]数据丢弃率（Drop Rate）[/color][/color]
[color=Green]-- 2 当Cache丢弃的数据量大于该Cache定义的[color=Blue]最少丢弃量（Drop Count Min）[/color][/color]
[color=Green]-- 与重新索引相关的缺省常量[/color]
CACHE_REINDEX_DROPRATE_DEF = 0.5 [color=Green]-- Cache丢弃的数据与有效数据比例[/color]
CACHE_REINDEX_DROPCOUNT_MIN = 50 [color=Green]-- Cache丢弃的数据量[/color]
[/quote]
[language=lua]CACHE_SIZE_ALL = -1
CACHE_SIZE_NONE = 0
CACHE_SIZE_DEF = 20
CACHE_REINDEX_DROPRATE_DEF = 0.5
CACHE_REINDEX_DROPCOUNT_MIN = 50
local map = {}
local function cache_free(ob)
ob.dropCount = 0
ob.startIndex = 1
ob.map = {}
ob.arr = {}
end
local function cache_reindex(ob, bForce)
bForce = bForce or false
local cSize = #ob.arr - ob.dropCount
if bForce or (ob.dropCount >= ob.dropCountMin and #ob.arr >= ob.size * (1 + ob.dropRate)) then
local arr = {}
local key, data
local j = 1
for i = ob.startIndex, #ob.arr do
key = ob.arr[ i ]
if type(key) == "string" then
data = ob.map[key]
arr[j] = key
data.index = j
j = j + 1
end
end
ob.arr = arr
ob.dropCount = 0
ob.startIndex = 1
end
end
local function cache_adjust (ob, key)
local data = ob.map[key]
local iLen = #ob.arr
if data.index < iLen then
ob.arr[data.index] = 0
ob.arr[iLen + 1] = key
data.index = iLen + 1
ob.dropCount = ob.dropCount + 1
cache_reindex(ob)
end
end
local function cache_keepSize(ob)
if ob.size == CACHE_SIZE_ALL then
return
end
local iLen = #ob.arr
local dc = ob.dropCount
local cSize = iLen - dc
local key
while cSize > ob.size do
for i = ob.startIndex, iLen do
ob.startIndex = ob.startIndex + 1
key = ob.arr[ i ]
if type(key) == "string" then
ob.map[key] = nil
ob.arr[ i ] = 0
ob.dropCount = ob.dropCount + 1
ob.cSize = ob.cSize - 1
break
end
end
if dc == ob.dropCount then
--[[ "Error : keep size of Cache ["..name.."] failed!" ]]
break
end
end
if dc < ob.dropCount then
cache_reindex(ob)
end
end
local function cache_resize(ob, size)
if ob.size == size then
return true
elseif size == CACHE_SIZE_ALL then
ob.size = size
elseif size == CACHE_SIZE_NONE then
cache_free(ob)
ob.size = size
elseif size > 0 then
if ob.size > size then
ob.size = size
cache_keepSize(ob)
else
ob.size = size
end
else
--[[ "Error : Cache ["..name.."] size must > 0!" ]]
end
end
local function cache_getValue(ob, key)
local data = ob.map[key]
if data == nil then
return nil
end
cache_adjust(ob, key)
return data.value
end
local function cache_setValue(ob, key, value)
local data = ob.map[key]
if data == nil then
data = {value = value, index = #ob.arr + 1}
ob.map[key] = data
ob.arr[data.index] = key
cache_keepSize(ob)
else
data.value = value
cache_adjust(ob, key)
end
return true
end
cache = {}
cache.create = function(name, type, size, droprate, dropcountmin)
local c = map[name]
if c == nil then
c = {
type = type or CACHE_TYPE_KEEP,
size = size or CACHE_SIZE_DEF,
dropRate = droprate or CACHE_REINDEX_DROPRATE_DEF,
dropCountMin = dropcountmin or CACHE_REINDEX_DROPCOUNT_MIN,
dropCount = 0,
startIndex = 1,
map = {},
arr = {},
}
map[name] = c
else
--[[ "Warning : Cache ["..name.."] already exist!" ]]
end
return c
end
cache.release = function(name)
local c = map[name]
if c ~= nil then
cache.clear(c, true)
map[name] = nil
c = nil
end
end
cache.clear = function(name, bForce)
bForce = bForce or false
local c = map[name]
if c ~= nil then
if bForce or c.type ~= CACHE_TYPE_KEEP then
cache_free(c)
end
end
end
cache.resize = function(name, size)
local c = map[name]
if c == nil then
--[[ "Warning : Cache ["..name.."] does not exist!" ]]
return nil
end
return cache_resize(c, size)
end
cache.get = function(name, key)
local c = map[name]
if c == nil then
-- [[ "Warning : Cache ["..name.."] does not exist!" ]]
return nil
end
if c.size == CACHE_SIZE_NONE then
return nil
end
return cache_getValue(c, key)
end
cache.set = function(name, key, value)
local c = map[name]
if c == nil then
--[[ "Warning : Cache ["..name.."] does not exist!" ]]
return nil
end
if c.size == CACHE_SIZE_NONE then
return false
end
return cache_setValue(c, key, value)
end[/language][/color][/color] 来段简要说明啊 fr你想表达什么意思? [quote]原帖由 [i]月色狼影[/i] 于 2007-8-26 22:53 发表 [url=http://bbs.cwowaddon.com/redirect.php?goto=findpost&pid=15351&ptid=1455][img]http://bbs.cwowaddon.com/images/common/back.gif[/img][/url]
fr你想表达什么意思? [/quote]
。。。这个。。。没啥意思呀
就是Cache的管理代码而已。。。 [quote]原帖由 [i]simonw[/i] 于 2007-8-25 19:46 发表 [url=http://bbs.cwowaddon.com/redirect.php?goto=findpost&pid=15225&ptid=1455][img]http://bbs.cwowaddon.com/images/common/back.gif[/img][/url]
来段简要说明啊 [/quote]
说明补了。。。
PS：其实我觉得没啥好写，这个代码不复杂
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