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use std::str::FromStr;
use std::marker::Copy;
use std::fmt::Debug;
use num_traits::Num;
use handler::ErrorCases::{AbsError, NegError, Overflow};
use handler::ErrorCases;
pub enum Operator {
Add,
Sub,
Mul,
Div,
Rem,
Abs,
Neg,
}
pub trait CheckedType
: Num
+ Copy
+ Debug
+ Ord
+ FromStr
+ ToString
+ Clone
+ CheckedAdd
+ CheckedSub
+ CheckedMul
+ CheckedDiv
+ CheckedRem
+ CheckedAbs
+ CheckedNeg {
}
pub trait CheckedAdd: Sized {
fn checked_add(&self, rhs: &Self) -> Result<Self, ErrorCases>;
}
pub trait CheckedSub: Sized {
fn checked_sub(&self, rhs: &Self) -> Result<Self, ErrorCases>;
}
pub trait CheckedMul: Sized {
fn checked_mul(&self, rhs: &Self) -> Result<Self, ErrorCases>;
}
pub trait CheckedDiv: Sized {
fn checked_div(&self, rhs: &Self) -> Result<Self, ErrorCases>;
}
pub trait CheckedRem: Sized {
fn checked_rem(&self, rhs: &Self) -> Result<Self, ErrorCases>;
}
pub trait CheckedAbs: Sized {
fn checked_abs(&self) -> Result<Self, ErrorCases>;
}
pub trait CheckedNeg: Sized {
fn checked_neg(&self) -> Result<Self, ErrorCases>;
}
macro_rules! checked_impl_double {
($trait_name:ident, $method:ident, $t:ty, $error_type: ident) => {
impl $trait_name for $t {
fn $method(&self, rhs: &$t) -> Result<Self, ErrorCases> {
<$t>::$method(*self, *rhs).ok_or($error_type)
}
}
}
}
macro_rules! checked_impl_single {
($trait_name:ident, $method:ident, $t:ty, $error_type: ident) => {
impl $trait_name for $t {
fn $method(&self) -> Result<Self, ErrorCases> {
<$t>::$method(*self).ok_or($error_type)
}
}
}
}
pub fn safe_calc<T: CheckedType>(a: &T, b: &T, op: &Operator) -> Result<T, ErrorCases> {
match *op {
Operator::Add => CheckedAdd::checked_add(a, b),
Operator::Sub => CheckedSub::checked_sub(a, b),
Operator::Mul => CheckedMul::checked_mul(a, b),
Operator::Div => CheckedDiv::checked_div(a, b),
Operator::Rem => CheckedRem::checked_rem(a, b),
Operator::Abs => CheckedAbs::checked_abs(a),
Operator::Neg => CheckedNeg::checked_neg(a),
}
}
impl CheckedType for usize {}
checked_impl_double!(CheckedAdd, checked_add, usize, Overflow);
checked_impl_double!(CheckedSub, checked_sub, usize, Overflow);
checked_impl_double!(CheckedMul, checked_mul, usize, Overflow);
checked_impl_double!(CheckedDiv, checked_div, usize, Overflow);
checked_impl_double!(CheckedRem, checked_rem, usize, Overflow);
checked_impl_single!(CheckedNeg, checked_neg, usize, NegError);
impl CheckedAbs for usize {
fn checked_abs(&self) -> Result<Self, ErrorCases> {
Ok(*self)
}
}
impl CheckedType for i32 {}
checked_impl_double!(CheckedAdd, checked_add, i32, Overflow);
checked_impl_double!(CheckedSub, checked_sub, i32, Overflow);
checked_impl_double!(CheckedMul, checked_mul, i32, Overflow);
checked_impl_double!(CheckedDiv, checked_div, i32, Overflow);
checked_impl_double!(CheckedRem, checked_rem, i32, Overflow);
checked_impl_single!(CheckedAbs, checked_abs, i32, AbsError);
checked_impl_single!(CheckedNeg, checked_neg, i32, NegError);