标签：digits end int 四则运算 整数 sign Lua return local

看代码吧

local table_concat = table.concat
local table_insert = table.insert
local string_rep = string.rep

SIGN_MINUS = "+" -- 正数
SIGN_PLUS = "-" -- 负数

NUM_FUL = 10 -- math.pow(10, 8)
NUM_MAX = NUM_FUL-1
NUM_MIN = -NUM_MAX
NUM_MAX_LEN = #tostring(NUM_MAX)

M = {}

--------------------------------------------------------
uuid = 1
function get_uuid()
	uuid = uuid + 1
	return uuid
end

function digitsIntToString(int, len_max)
	-- 补0
	len_max = len_max or NUM_MAX_LEN
	local s = tostring(int)
	local zero_number = len_max - #s
	local s_zero = string_rep("0", zero_number)
	return table_concat({ s_zero, s })
end

function getBigNumber(n, bSafe)
	bSafe = bSafe or true
	if isBigNumber(n) then
		if bSafe then
			return n:copy()
		end
	else
		return M:create(n)
	end
end

function isBigNumber(n)
	if type(n) == "table" and getmetatable(n) == M then
		return true
	end
	return false
end

function digitsUp(digits)
	-- 保证进位正常
	local size = #digits
	for i=1, size do
		if digits[i] > NUM_MAX then
			digits[i] = digits[i] - NUM_MAX - 1
			if not digits[i + 1] then
				digits[i + 1] = 0
			end
			digits[i + 1] = digits[i + 1] + 1
		end
	end
end

--------------------------------------------------------

function div(a_in, b_in)
	-- 计算结果、余数
	-- 默认步长10
	assert(b ~= 0, "ERROR: 0不能作为除数")

	local sign
	if a_in:getSign() == b_in:getSign() then
		sign = SIGN_MINUS
	else
		sign = SIGN_PLUS
	end
	local a = M.createBySignDigits(SIGN_MINUS, a_in:getDigits())
	local b = M.createBySignDigits(SIGN_MINUS, b_in:getDigits())

	if a == 0 then
		return 0, 0
	end
	if b == 1 then
		return a, 0
	end
	if a < b then
		return 0, a
	end
	--if a == b then
	--	return 1, 0
	--end

	local function calc(a, b)
		assert(b ~= 0, "ERROR: 0不能作为除数")
		assert(a >= b, "ERROR：被除数不小于除数")

		a = getBigNumber(a)
		b = getBigNumber(b)

		local factor = M:create(1) -- 倍率
		for i = 1, #a._digits - #b._digits - 1 do
			table_insert(b._digits, 1, 0)
			table_insert(factor._digits, 1, 0)
		end
		if #a._digits ~= #b._digits then
			local b_copy = b:copy()
			table_insert(b_copy._digits, 1, 0)
			if a > b_copy then
				b = b_copy
				table_insert(factor._digits, 1, 0)
			end
		end

		local time = 0 -- 次数
		while a >= b do
			a = a - b
			time = time + 1
		end
		factor._digits[#factor._digits] = factor._digits[#factor._digits] * time
		return M.createBySignDigits(SIGN_MINUS, factor:getDigits()), M.createBySignDigits(SIGN_MINUS, a:getDigits())
	end

	local q = 0
	local f
	local a_new
	while a >= b do
		f, a_new = calc(a, b)
		q = q + f
		a = a_new
	end

	-- 负数除法的特殊处理（-3/2 ~= -(3/2)）
	if sign == SIGN_PLUS and not a:isZero() then
		q = q + 1
	end

	q._sign = sign
	return q, a
end
function M.__add(a_in, b_in)
	local a = getBigNumber(a_in)
	local b = getBigNumber(b_in)

	local sign
	local digits

	local a_sign = a:getSign()
	local b_sign = b:getSign()
	local a_digits = a:getDigits()
	local b_digits = b:getDigits()
	local a_size = #a_digits
	local b_size = #b_digits
	local max_size = a_size > b_size and a_size or b_size
	if a_sign == b_sign then
		digits = {}
		local sum, a_int, b_int, c_int
		for i = 1, max_size do
			a_int = a_digits[i] or 0
			b_int = b_digits[i] or 0
			c_int = digits[i] or 0
			sum = a_int + b_int + c_int
			if sum > NUM_MAX then
				digits[i] = sum - NUM_MAX - 1
				digits[i + 1] = 1
			else
				digits[i] = sum
			end
		end
		sign = a_sign
	else
		digits = {}
		local sum, a_int, b_int, c_int
		if a_size > b_size then
			for i = 1, a_size do
				a_int = a_digits[i]
				b_int = b_digits[i] or 0
				if a_int >= b_int then
					digits[i] = a_int - b_int
				else
					local flag = true
					for ii = i + 1, a_size do
						if flag then
							if a_digits[ii] == 0 then
								a_digits[ii] = NUM_MAX
							else
								a_digits[ii] = a_digits[ii] - 1
								flag = false
							end
						end
					end
					if flag then
						print("error 403")
						return
					end
					digits[i] = a_int - b_int + NUM_MAX + 1
				end
			end
			sign = a_sign
		elseif a_size < b_size then
			for i = 1, b_size do
				b_int = b_digits[i]
				a_int = a_digits[i] or 0
				if b_int >= a_int then
					digits[i] = b_int - a_int
				else
					local flag = true
					for ii = i + 1, b_size do
						if flag then
							if b_digits[ii] == 0 then
								b_digits[ii] = NUM_MAX
							else
								b_digits[ii] = b_digits[ii] - 1
								flag = false
							end
						end
					end
					if flag then
						print("error 403")
						return
					end
					digits[i] = b_int - a_int + NUM_MAX + 1
				end
			end
			sign = b_sign
		else
			local is_a_can = true
			for i = 1, a_size do
				a_int = a_digits[i]
				b_int = b_digits[i]
				if a_int >= b_int then
					digits[i] = a_int - b_int
				else
					local success = false
					for ii = i + 1, a_size do
						if a_digits[ii] == 0 then
							a_digits[ii] = NUM_MAX
						else
							a_digits[ii] = a_digits[ii] - 1
							success = true
							break
						end
					end
					if success then
						digits[i] = a_int - b_int + NUM_MAX + 1
					else
						is_a_can = false
						break
					end
				end
			end
			if is_a_can then
				sign = a_sign
			else
				digits = {}
				local a = getBigNumber(a_in)
				local a_digits = a:getDigits()
				for i = 1, b_size do
					b_int = b_digits[i]
					a_int = a_digits[i] or 0
					if b_int >= a_int then
						digits[i] = b_int - a_int
					else
						local flag = true
						for ii = i + 1, b_size do
							if flag then
								if b_digits[ii] == 0 then
									b_digits[ii] = NUM_MAX
								else
									b_digits[ii] = b_digits[ii] - 1
									flag = false
								end
							end
						end
						if flag then
							print("error 404")
							return
						end
						digits[i] = b_int - a_int + NUM_MAX + 1
					end
				end
				sign = b_sign
			end
		end
	end
	return M.createBySignDigits(sign, digits)

end
function M.__sub(a, b)
	return getBigNumber(a) + (-getBigNumber(b))
end

function M.__mul(a, b)
	local a = getBigNumber(a)
	local b = getBigNumber(b)

	local a_digits = a:getDigits()
	local b_digits = b:getDigits()
	local a_sign = a:getSign()
	local b_sign = b:getSign()

	local a_size = #a_digits
	local b_size = #b_digits

	local int_mul
	local str_mul
	local height_mul
	local cur_mul

	local sign
	local digits = {}

	if a_sign == b_sign then
		sign = SIGN_MINUS
	else
		sign = SIGN_PLUS
	end

	for i=1, a_size + b_size do
		digits[i] = 0
	end
	for i = 1, a_size do
		for j = 1, b_size do
			int_mul = a_digits[i] * b_digits[j]
			if int_mul >= NUM_FUL then
				height_mul = math.floor(int_mul / NUM_FUL)
				cur_mul = int_mul % NUM_FUL
			else
				cur_mul = int_mul
				height_mul = 0
			end
			digits[i + j - 1] = digits[i + j - 1] + cur_mul
			digitsUp(digits)
			digits[i + j] = digits[i + j] + height_mul
			digitsUp(digits)
		end
	end
	return M.createBySignDigits(sign, digits)
end
function M.__div(a, b)
	local m, n = div(a, b)
	return m
end
function M.__mod(a, b)
	local m, n = div(a, b)
	return n
end
function M.__pow(a, b)

end
function M.__unm(o)
	o = getBigNumber(o)
	if o._sign == SIGN_MINUS then
		o._sign = SIGN_PLUS
	else
		o._sign = SIGN_MINUS
	end
	return o
end
function M.__idiv(o)

end
function M.__band(o)

end
function M.__bor(o)

end
function M.__bxor(o)

end
function M.__bno(o)

end
function M.__shl(o)

end
function M.__shr(o)

end
function M.__concat(o)

end
function M.__len(o)
	local digits_len = 0
	local sign_len = 0
	local digits = o:getDigits()
	local i = #digitsl
	if i == 0 then
		digits_len = 0
	elseif i == 1 then
		digits_len = #tostring(digits[1])
	elseif i > 1 then
		digits_len = (i - 1) * NUM_MAX_LEN + #tostring(digits[i])
	else
		return -1
	end
	if o:getSign() == SIGN_PLUS then
		sign_len = 1
	end
	return sign_len + digits_len
end
function M.__eq(a, b)
	a = getBigNumber(a)
	b = getBigNumber(b)
	return a:getSign() == b:getSign() and #a:getDigits() == #b:getDigits() and tostring(a) == tostring(b)
end
function M.__lt(a, b)
	a = getBigNumber(a)
	b = getBigNumber(b)

	local a_sign = a:getSign()
	local b_sign = b:getSign()

	-- 优化与0比较
	local a_isZero = a:isZero()
	local b_isZero = b:isZero()
	if a_isZero or b_isZero then
		if not a_isZero then
			return a_sign == SIGN_PLUS
		elseif not b_isZero then
			return b_sign == SIGN_MINUS
		else
			return false
		end
	end
	-- 优化与0比较

	if a_sign ~= b_sign then
		if a_sign == SIGN_PLUS then
			return true
		else
			return false
		end
	else
		if a_sign == SIGN_MINUS then
			local c = a - b
			if c:isZero() then
				return false
			end
			if c:getSign() == SIGN_PLUS then
				return true
			else
				return false
			end
		else
			local c = (-a) - (-b)
			if c:isZero() then
				return false
			end
			if c:getSign() == SIGN_MINUS then
				return true
			else
				return false
			end
		end
	end
end
function M.__le(a, b)
	a = getBigNumber(a)
	b = getBigNumber(b)

	local a_sign = a:getSign()
	local b_sign = b:getSign()

	-- 优化与0比较
	local a_isZero = a:isZero()
	local b_isZero = b:isZero()
	if a_isZero or b_isZero then
		if not a_isZero then
			return a_sign == SIGN_PLUS
		elseif not b_isZero then
			return b_sign == SIGN_MINUS
		else
			return true
		end
	end
	-- 优化与0比较

	if a_sign ~= b_sign then
		if a_sign == SIGN_PLUS then
			return true
		else
			return false
		end
	else
		if a_sign == SIGN_MINUS then
			local c = a - b
			if c:isZero() then
				return true
			end
			if c:getSign() == SIGN_PLUS then
				return true
			else
				return false
			end
		else
			local c = (-a) - (-b)
			if c:isZero() then
				return true
			end
			if c:getSign() == SIGN_MINUS then
				return true
			else
				return false
			end
		end
	end
end
function M.__tostring(o)
	if o == nil then
		return "object is nil"
	end
	if not o._sign then
		return "object is no sign"
	end
	if not o._digits then
		return "object is no digits"
	end

	if o:isZero() then
		return "0"
	end

	local result
	if o._sign == SIGN_PLUS then
		result = { "-", }
	else
		result = { "", }
	end
	for k, v in pairs(o._digits) do
		if k == #o._digits then
			table_insert(result, 2, tostring(v))
		else
			table_insert(result, 2, digitsIntToString(v))
		end
	end
	return table_concat(result)
end
function M:_setString(n)
	n = tostring(n)
	if n:sub(1, 1) == "-" then
		self._sign = SIGN_PLUS
		n = n:sub(2)
	elseif n:sub(1, 1) == "+" then
		self._sign = SIGN_MINUS
		n = n:sub(2)
	else
		self._sign = SIGN_MINUS
	end
	n = n:gsub("^0*", "")
	local str;
	local int;
	self._digits = {}
	for index = 1, #n, NUM_MAX_LEN do
		str = n:sub(-index - NUM_MAX_LEN + 1, -index)
		int = tonumber(str)
		table_insert(self._digits, int)
	end
	if #self._digits == 0 then
		table_insert(self._digits, 0)
	end
end
function M._checkValid(n)
	if not (type(n) == "number" or type(n) == "string") then
		print("暂时不支持此类型参数", type(n))
		return
	end
	n = tostring(n)
	if string.match(n, " ") then
		print("_checkValid error 400", n)
		return
	end
	local tmp = n:gsub("-?+?%.?", "")
	if string.match(tmp, "%D") then
		print("_checkValid error 401", n)
		return
	end
	n = n:gsub("%.%d*", "")
	if n == "" then
		print("_checkValid error 402", n)
		return
	end
	return true
end
function M.createBySignDigits(sign, digits)
	local o = M:create(0)
	o._sign = sign or SIGN_MINUS
	digits = digits or {}

	local function getDigitsSize(d)
		local k
		for i = 1, #d do
			k = #d - i + 1
			if d[k] ~= 0 then
				return k
			end
		end
		return 0
	end

	local size = getDigitsSize(digits)

	for i = 1, size do
		o._digits[i] = digits[i]
	end
	return o
end
function M:isZero()
	if #self._digits == 0 then
		return true
	end
	local zero = true
	for k, v in pairs(self._digits) do
		if v ~= 0 then
			zero = false
		end
	end
	return zero
end
function M:getSign()
	return self._sign
end
function M:getDigits()
	return self._digits
end
function M:copy()
	return M.createBySignDigits(self._sign, self._digits)
end
function M:create (n)
	if self ~= M or n == nil then
		return nil
	end
	if isBigNumber(n) then
		return n:copy()
	end
	if not self._checkValid(n) then
		return nil
	end
	local o = {}
	setmetatable(o, self)
	self.__index = self
	self._ori_number = n
	self._id = get_uuid()
	o:_setString(n)
	return o
end

CBigInt = M

标签：digits,end,int,四则运算,整数,sign,Lua,return,local
来源： https://blog.csdn.net/hunter_wyh/article/details/122093736

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