lua的table, string, class常用扩展

-- lua扩展

-- table扩展


-- 返回table大小
table.size = function(t)
    local count = 0
    for _ in pairs(t) do
        count = count + 1
    end
    return count
end

--返回table的最大value
table.maxn = function(t)
    local maxn = nil
    for _, v in pairs(t) do
        if nil == maxn then
            maxn = v
        end
        if maxn < v then
            maxn = v
        end
    end
    return maxn
end

--返回table的最小value
table.minn = function(t)
    local min = nil
    for _, v in pairs(t) do
        if nil == min then
            min = v
        end
        if min > v then
            min = v
        end
    end
    return min
end

-- 判断table是否为空
table.empty = function(t)
    return not next(t)
end

-- 返回table索引列表
table.indices = function(t)
    local result = {}
    for k, v in pairs(t) do
        table.insert(result, k)
    end
    return result
end

-- 返回table值列表
table.values = function(t)
    local result = {}
    for k, v in pairs(t) do
        table.insert(result, v)
    end
    return result
end

-- 浅拷贝
table.clone = function(t, nometa)
    local result = {}
    if not nometa then
        setmetatable(result, getmetatable(t))
    end
    for k, v in pairs (t) do
        result[k] = v
    end
    return result
end

-- 深拷贝
table.copy = function(t, nometa)
    local result = {}

    if not nometa then
        setmetatable(result, getmetatable(t))
    end

    for k, v in pairs(t) do
        if type(v) == "table" then
            result[k] = table.copy(v, nometa)
        else
            result[k] = v
        end
    end
    return result
end

table.merge = function(dest, src)
    for k, v in pairs(src) do
        dest[k] = v
    end
end

table.random = function(tbl)
    local len = #tbl
    if len == 1 then
        return tbl
    end
    for i = 1, len do
        local ranOne = math.random(1, len+1-i)
        tbl[ranOne], tbl[len+1-i] = tbl[len+1-i],tbl[ranOne]
    end
    return tbl
end

table.contain = function(t, val)
    for _, v in pairs(t) do
        if v == val then
            return true
        end
    end
    return false
end

table.count = function(t, val)
    local cnt = 0
    for _, v in pairs(t) do
        if v == val then
            cnt = cnt + 1
        end
    end
    return cnt
end

table.sum = function(t)
    local s = 0
    for _, v in pairs(t) do
        s = s + v
    end
    return s
end

table.sub = function(t, start, count)
    local st = {}
    for i = 1, count do
        table.insert(st, t[start+i-1])
    end
    return st
end

table.findIdx = function(t, val)
    for k, v in ipairs(t) do
        if v == val then
            return k
        end
    end
    return -1
end

table.removeVal = function(t, val)
    for k, v in ipairs(t) do
        if v == val then
            return table.remove(t, k)
        end
    end
end

--用val填充table
table.fill = function(t, val, count)
    if not count then count = #t end
    for i = 1, count do
        t[i] = val
    end
    return t
end

table.shuffle = function(t)
    for i = #t, 2, -1 do
        local j = math.random(i)
        t[i], t[j] = t[j], t[i]
    end
    return t
end

-- string扩展

-- 下标运算
do
    local mt = getmetatable("")
    local _index = mt.__index

    mt.__index = function (s, ...)
        local k = ...
        if "number" == type(k) then
            return _index.sub(s, k, k)
        else
            return _index[k]
        end
    end
end

string.split = function(s, delim)
    local split = {}
    local pattern = "[^" .. delim .. "]+"
    string.gsub(s, pattern, function(v) table.insert(split, v) end)
    return split
end

string.ltrim = function(s, c)
    local pattern = "^" .. (c or "%s") .. "+"
    return (string.gsub(s, pattern, ""))
end

string.rtrim = function(s, c)
    local pattern = (c or "%s") .. "+" .. "$"
    return (string.gsub(s, pattern, ""))
end

string.trim = function(s, c)
    return string.rtrim(string.ltrim(s, c), c)
end

string.split_to_number = function(s, delim)
    local split = {}
    local pattern = "[^" .. delim .. "]+"
    string.gsub(s, pattern, function(v) table.insert(split, tonumber(v)) end)
    return split
end

--safe floor（针对math.floor传入nil或非数字字符串会报错）
math.sfloor = function (value)
    value = tonumber(value)
    if value ~= nil then
        return math.floor(value)
    end
    return nil
end

--金币保留两位小数
math.round_coin = function (value)
    return math.floor(value*100+0.5)/100
end

local function dump(obj)
    local getIndent, quoteStr, wrapKey, wrapVal, dumpObj
    getIndent = function(level)
        return string.rep("\t", level)
    end
    quoteStr = function(str)
        return '"' .. string.gsub(str, '"', '\\"') .. '"'
    end
    wrapKey = function(val)
        if type(val) == "number" then
            return "[" .. val .. "]"
        elseif type(val) == "string" then
            return "[" .. quoteStr(val) .. "]"
        else
            return "[" .. tostring(val) .. "]"
        end
    end
    wrapVal = function(val, level)
        if type(val) == "table" then
            return dumpObj(val, level)
        elseif type(val) == "number" then
            return val
        elseif type(val) == "string" then
            return quoteStr(val)
        else
            return tostring(val)
        end
    end
    dumpObj = function(obj, level)
        if type(obj) ~= "table" then
            return wrapVal(obj)
        end
        level = level + 1
        local tokens = {}
        tokens[#tokens + 1] = "{"
        for k, v in pairs(obj) do
            tokens[#tokens + 1] = getIndent(level) .. wrapKey(k) .. " = " .. wrapVal(v, level) .. ","
        end
        tokens[#tokens + 1] = getIndent(level - 1) .. "}"
        return table.concat(tokens, "\n")
    end
    return dumpObj(obj, 0)
end

do
    local _tostring = tostring
    tostring = function(v)
        if type(v) == 'table' then
            return dump(v)
        else
            return _tostring(v)
        end
    end
end

-- math扩展
do
    local _floor = math.floor
    math.floor = function(n, p)
        if p and p ~= 0 then
            local e = 10 ^ p
            return _floor(n * e) / e
        else
            return _floor(n)
        end
    end
end

math.round = function(n, p)
        local e = 10 ^ (p or 0)
        return math.floor(n * e + 0.5) / e
end


-- lua面向对象扩展
local _class={}

function class(super)
    local class_type={}
    class_type.ctor=false
    class_type.super=super
    class_type.new=function(...)
            local obj={}
            do
                local create
                create = function(c,...)
                    if c.super then
                        create(c.super,...)
                    end
                    if c.ctor then
                        c.ctor(obj,...)
                    end
                end

                create(class_type,...)
            end
            setmetatable(obj,{ __index=_class[class_type] })
            return obj
        end
    local vtbl={}
    _class[class_type]=vtbl

    setmetatable(class_type,{__newindex=
        function(t,k,v)
            vtbl[k]=v
        end
    })

    if super then
        setmetatable(vtbl,{__index=
            function(t,k)
                local ret=_class[super][k]
                vtbl[k]=ret
                return ret
            end
        })
    end

    return class_type
end