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#[macro_use]
mod plain_enum {
#[macro_export]
macro_rules! enum_seq_len {
($n: expr, $enumval: ident,) => ($n);
($n: expr, $enumval: ident, $($enumvals: ident,)*) => (enum_seq_len!(($n + 1), $($enumvals,)*));
}
use std::iter;
use std::ops;
pub trait TPlainEnum : Sized {
fn valid_usize(u: usize) -> bool;
fn from_usize(u: usize) -> Self;
fn checked_from_usize(u: usize) -> Option<Self>;
fn wrapped_from_usize(u: usize) -> Self;
fn wrapped_difference(self, e_other: Self) -> usize;
fn to_usize(self) -> usize;
fn ubound_usize() -> usize;
fn values() -> iter::Map<ops::Range<usize>, fn(usize) -> Self> {
(0..Self::ubound_usize())
.map(Self::from_usize)
}
fn wrapping_add(self, n_offset: usize) -> Self;
}
pub trait TEnumMapType<T> : TPlainEnum {
type MapType;
}
#[allow(dead_code)]
pub type EnumMap<PlainEnum, T> = <PlainEnum as TEnumMapType<T>>::MapType;
#[macro_export]
macro_rules! acc_arr {
($func: ident, [$($acc: expr,)*], []) => {
[$($acc,)*]
};
($func: ident, [$($acc: expr,)*], [$enumval: ident, $($enumvals: ident,)*]) => {
acc_arr!($func, [$($acc,)* $func($enumval),], [$($enumvals,)*])
};
}
#[macro_export]
macro_rules! plain_enum_mod {
($modname: ident, $enumname: ident {
$($enumvals: ident,)*
} ) => {
mod $modname {
use plain_enum::*;
use std::slice;
#[repr(usize)]
#[derive(PartialEq, Eq, Debug, Copy, Clone, PartialOrd, Ord, Hash)]
pub enum $enumname {
$($enumvals,)*
}
const ENUMSIZE : usize = enum_seq_len!(1, $($enumvals,)*);
impl TPlainEnum for $enumname {
fn ubound_usize() -> usize {
ENUMSIZE
}
fn valid_usize(u: usize) -> bool {
u < ENUMSIZE
}
fn from_usize(u: usize) -> Self {
use std::mem;
debug_assert!(Self::valid_usize(u));
unsafe{mem::transmute(u)}
}
fn checked_from_usize(u: usize) -> Option<Self> {
if Self::valid_usize(u) {
Some(Self::from_usize(u))
} else {
None
}
}
fn wrapped_from_usize(u: usize) -> Self {
Self::from_usize(u % ENUMSIZE)
}
fn wrapped_difference(self, e_other: Self) -> usize {
(self.to_usize() + ENUMSIZE - e_other.to_usize()) % ENUMSIZE
}
fn to_usize(self) -> usize {
self as usize
}
fn wrapping_add(self, n_offset: usize) -> Self {
Self::from_usize((self.to_usize() + n_offset) % ENUMSIZE)
}
}
impl $enumname {
#[allow(dead_code)]
pub fn map_from_fn<F, T>(mut func: F) -> Map<T>
where F: FnMut($enumname) -> T,
{
use self::$enumname::*;
Map::from_raw(acc_arr!(func, [], [$($enumvals,)*]))
}
#[allow(dead_code)]
pub fn map_from_raw<T>(at: [T; ENUMSIZE]) -> Map<T> {
Map::from_raw(at)
}
}
impl<T> TEnumMapType<T> for $enumname {
type MapType = Map<T>;
}
use std::ops::{Index, IndexMut};
#[derive(PartialEq, Debug)]
pub struct Map<T> {
m_at : [T; ENUMSIZE],
}
impl<T> Index<$enumname> for Map<T> {
type Output = T;
fn index(&self, e : $enumname) -> &T {
&self.m_at[e.to_usize()]
}
}
impl<T> IndexMut<$enumname> for Map<T> {
fn index_mut(&mut self, e : $enumname) -> &mut Self::Output {
&mut self.m_at[e.to_usize()]
}
}
impl<T> Map<T> {
#[allow(dead_code)]
pub fn iter(&self) -> slice::Iter<T> {
self.m_at.iter()
}
pub fn from_raw(at: [T; ENUMSIZE]) -> Map<T> {
Map {
m_at : at,
}
}
}
}
pub use self::$modname::$enumname;
}
}
}
pub use plain_enum::TPlainEnum;
pub use plain_enum::TEnumMapType;
pub use plain_enum::EnumMap;
#[cfg(test)]
mod tests {
use plain_enum::*;
plain_enum_mod!{test_module, ETest {
E1, E2, E3,
}}
#[test]
fn test_plain_enum() {
assert_eq!(3, enum_seq_len!(1, E1, E2, E3,));
assert_eq!(3, ETest::ubound_usize());
}
#[test]
fn test_values() {
assert_eq!(vec![ETest::E1, ETest::E2, ETest::E3], ETest::values().collect::<Vec<_>>());
assert_eq!(ETest::values().count(), 3);
assert_eq!((3, Some(3)), ETest::values().size_hint());
assert_eq!(3, ETest::values().len());
assert!(ETest::values().eq(ETest::values().rev().rev()));
}
fn type_test(_map: &EnumMap<ETest, usize>) {}
#[test]
fn test_enummap() {
let mut map_test_to_usize = ETest::map_from_fn(|test| test.to_usize());
for test in ETest::values() {
assert_eq!(map_test_to_usize[test], test.to_usize());
}
for test in ETest::values() {
map_test_to_usize[test] += 1;
}
for test in ETest::values() {
assert_eq!(map_test_to_usize[test], test.to_usize()+1);
}
type_test(&map_test_to_usize);
}
}