devela/num/niche/non_value.rs
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// devela::num::niche::non_value
//
//! Creates const generic customizable wrappers over the `NonZero` primitives.
//!
//! Always available for internal use.
//
// Centralized automatic definitions based on enabled features & flags
#[cfg(any(doc, test))]
impl_non_value![I 8];
#[cfg(feature = "_char7")]
impl_non_value![U 8];
#[cfg(feature = "_char16")]
impl_non_value![U 16];
/// Implements a `NonValue[I|U]B<V>`.
///
/// - `I` or `U` means a signed or unsigned type, respectively.
/// - `B` represents the bit-size, from [8, 16, 32, 64, 128].
/// - `V` is the prohibited value in the bit-sized range.
///
/// # Example
/// ```
/// # use devela::impl_non_value;
/// impl_non_value![I 8];
///
/// assert![NonValueI8::<3>::new(2).is_some()];
/// assert![NonValueI8::<3>::new(3).is_none()];
///
/// assert![NonExtremeI8::new(i8::MIN).is_none()];
/// assert![NonExtremeI8::new(i8::MAX).is_some()];
/// assert![NonExtremeI8::new(0).is_some()];
/// ```
///
/// See for example: [`NonValueI8`] and [`NonExtremeI8`].
//
// NOTE: can't use doc(cfg) attributes in generated methods.
#[macro_export]
#[cfg_attr(cargo_primary_package, doc(hidden))]
macro_rules! impl_non_value {
(
// Defines a new signed non-value type. E.g.: impl_non_value![i 32]
// would generate NonValueI32 and NonExtremeI32
I $bits:literal) => {
$crate::impl_non_value![@MIN, "A signed", i, $bits];
};
(
// Defines a new signed non-value type. E.g.: impl_non_value![u 32]
// would generate NonValueU32 and NonExtremeU32
U $bits:literal) => {
$crate::impl_non_value![@MAX, "An unsigned", u, $bits];
};
(
/* private arms */
@$XTR:ident, $doc:literal, $s:ident, $b:literal) => {
$crate::paste!{
$crate::impl_non_value![@
[<NonValue $s:upper $b>], // $name
[<NonZero $s:upper $b>], // $n0
[<NonExtreme $s:upper $b>], // $ne
$XTR,
$doc,
[<$s $b>], // $IP
$s,
$b
];
}
};
(
// $name: the full name of the new type. E.g. NonValueI8.
// $n0: the full name of the inner NonZero. E.g. NonZeroI8.
// $ne: the full name of the new type. E.g. NonExtremeI8.
//
// $XTR: the *extreme* value constant for this type. (MIN | MAX).
// $doc: the specific beginning of the documentation.
// $IP: the type of the corresponding integer primitive. E.g. i8
// $s: the sign identifier: i or u.
// $b: the bits of the type, from 8 to 128, or the `size` suffix.
@$name:ident, $n0:ident, $ne:ident, $XTR:ident, $doc:literal, $IP:ty, $s:ident, $b:literal)
=> { $crate::paste! {
pub use [<__impls_ $name >]::*;
#[allow(non_snake_case)]
mod [<__impls_ $name >] {
#[cfg(all(feature = "dep_bytemuck", feature = "unsafe_niche", not(feature = "safe_num")))]
use $crate::_dep::bytemuck::{CheckedBitPattern, NoUninit, PodInOption, ZeroableInOption};
// #[cfg(feature = "unsafe_layout")]
// use $crate::MemPod;
#[cfg(feature = "bit")]
use $crate::{BitSized, ByteSized};
use $crate::{
_core::num::*,
iif, unwrap, ConstDefault, FromStr, NumError::{Invalid, Overflow}, NumResult,
Debug, Display, FmtResult, Formatter, Binary, Octal, LowerHex, UpperHex,
};
/* definition */
#[doc = $doc " integer that is known not to equal some specific value." ]
///
#[doc = "It has the same memory layout optimization as [`" $n0 "`][core::num::" $n0 "],"]
#[doc = " so that `Option<" $name ">` is the same size as `" $name "`."]
///
/// # Examples
/// ```ignore
/// # use devela::NonValueI8;
/// assert![NonValueI8::<13>::new(13).is_none()];
/// assert![NonValueI8::<13>::new(12).unwrap().get() == 12];
/// ```
#[doc = "See also [`NonExtreme" $s:upper $b "`]."]
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct $name <const V: $IP>($n0);
/* aliases */
#[doc = $doc " integer that is known not to equal its most extreme value ([`"
$XTR "`][" $IP "::" $XTR "])."]
///
/// Unlike the `NonValue*` types in general, this type alias implements
/// the [`Default`] and [`ConstDefault`][crate::code::ConstDefault] traits.
pub type [<NonExtreme $s:upper $b>] = $name <{$IP::$XTR}>;
impl Default for [<NonExtreme $s:upper $b>] {
/// # Features
/// Makes use of the `unsafe_niche` feature if enabled.
#[must_use]
fn default() -> Self {
#[cfg(any(feature = "safe_num", not(feature = "unsafe_niche")))]
return [<NonExtreme $s:upper $b>]::new($IP::default()).unwrap();
#[cfg(all(not(feature = "safe_num"), feature = "unsafe_niche"))]
// SAFETY: the default primitive value is always 0, and their MAX is never 0.
unsafe { return [<NonExtreme $s:upper $b>]::new_unchecked($IP::default()); }
}
}
impl ConstDefault for [<NonExtreme $s:upper $b>] {
/// # Features
/// Makes use of the `unsafe_niche` feature if enabled.
const DEFAULT: Self = {
#[cfg(any(feature = "safe_num", not(feature = "unsafe_niche")))]
if let Some(v) = Self::new($IP::DEFAULT) { v } else { unreachable![] }
#[cfg(all(not(feature = "safe_num"), feature = "unsafe_niche"))]
// SAFETY: the default primitive value is always 0, and their MAX is never 0.
unsafe { [<NonExtreme $s:upper $b>]::new_unchecked($IP::DEFAULT) }
};
}
impl<const V: $IP> $name<V> {
/* constants */
/// Returns the maximum possible value.
pub const MAX: Self = {
if $IP::MAX > V {
unwrap![some Self::new($IP::MAX)]
} else {
unwrap![some Self::new($IP::MAX - 1)]
}
};
/// Returns the minimum possible value.
pub const MIN: Self = {
if $IP::MIN < V {
unwrap![some Self::new($IP::MIN)]
} else {
unwrap![some Self::new($IP::MIN + 1)]
}
};
/// Returns the number of valid values.
pub const VALID_VALUES: [<u $b>] = [<u $b>]::MAX;
/// Returns the number of invalid values.
pub const INVALID_VALUES: [<u $b>] = 1;
/* methods */
#[doc = "Returns a `" $name "` with the given `value`,"
" if it is not equal to `V`."]
#[must_use]
pub const fn new(value: $IP) -> Option<Self> {
match [<NonZero $s:upper $b>]::new(value ^ V) {
None => None,
Some(v) => Some(Self(v)),
}
}
#[doc = "Returns a `" $name "` if the given `value`" " if it is not equal to `V`."]
///
/// # Panics
/// Panics in debug if the given `value` is equal to `V`.
/// # Safety
/// The given `value` must never be equal to `V`.
#[must_use]
#[cfg(all(not(feature = "safe_num"), feature = "unsafe_niche"))]
pub const unsafe fn new_unchecked(value: $IP) -> Self {
#[cfg(debug_assertions)]
if value == V { panic!("The given value was specifically prohibited.") }
// SAFETY: caller must ensure safety
Self(unsafe { [<NonZero $s:upper $b>]::new_unchecked(value ^ V) })
}
/// Returns the value as a primitive type.
#[must_use]
pub const fn get(&self) -> $IP {
self.0.get() ^ V
}
/// Returns `true` if it is equal to the maximum value ([`MAX`][Self::MAX]).
#[must_use]
pub const fn is_max(&self) -> bool {
self.get() == $IP::MAX
}
/// Returns `true` if it is equal to the minimum value ([`MIN`][Self::MIN]).
#[must_use]
pub const fn is_min(&self) -> bool {
self.get() == $IP::MIN
}
/// Checked integer addition. Computes `self + rhs`.
///
/// # Errors
/// Returns [`Overflow`] if the operations overflows, or
/// [`Invalid`] if the result equals the forbidden value `V`.
pub const fn checked_add(&self, other: $IP) -> NumResult<Self> {
let res = unwrap![some_ok_or? self.get().checked_add(other), Overflow(None)];
unwrap![some_ok_or Self::new(res), Invalid]
}
/// Checked integer substration. Computes `self - rhs`.
///
/// # Errors
/// Returns [`Overflow`] if the operations overflows, or
/// [`Invalid`] if the result equals the forbidden value `V`.
pub const fn checked_sub(&self, other: $IP) -> NumResult<Self> {
let res = unwrap![some_ok_or? self.get().checked_sub(other), Overflow(None)];
unwrap![some_ok_or Self::new(res), Invalid]
}
/// Strict integer addition. Computes `self + rhs`.
///
/// # Panics
/// Panics on overflow or if the result equals the forbidden value `V`.
pub const fn strict_add(&self, other: $IP) -> Self {
let res = unwrap![some self.get().checked_add(other)];
unwrap![some Self::new(res)]
}
/// Strict integer substration. Computes `self - rhs`.
///
/// # Panics
/// Panics on overflow or if the result equals the forbidden value `V`.
pub const fn strict_sub(&self, other: $IP) -> Self {
let res = unwrap![some self.get().checked_sub(other)];
unwrap![some Self::new(res)]
}
/// Saturating integer addition. Computes `self + rhs`.
///
/// Saturates at the numeric bounds instead of overflowing.
/// If the result would equal `V` it will return `V - 1`.
pub const fn saturating_add(&self, other: $IP) -> Self {
let res = self.get().saturating_add(other);
unwrap![some Self::new(iif![res == V; res - 1; res])]
}
/// Saturating integer substration. Computes `self - rhs`.
///
/// Saturates at the numeric bounds instead of overflowing.
/// If the result would equal `V` it will return `V + 1`.
pub const fn saturating_sub(&self, other: $IP) -> Self {
let res = self.get().saturating_sub(other);
unwrap![some Self::new(iif![res == V; res + 1; res])]
}
/// Wraping integer addition. Computes `self + rhs`.
///
/// Wraps at the numeric bounds instead of overflowing.
/// If the result would equal `V` it will return `V + 1`.
pub const fn wrapping_add(&self, other: $IP) -> Self {
let res = self.get().wrapping_add(other);
unwrap![some Self::new(iif![res == V; res + 1; res])]
}
/// Wraping integer subtraction. Computes `self - rhs`.
///
/// Wraps at the numeric bounds instead of overflowing.
/// If the result would equal `V` it will return `V - 1`.
pub const fn wrapping_sub(&self, other: $IP) -> Self {
let res = self.get().wrapping_sub(other);
unwrap![some Self::new(iif![res == V; res - 1; res])]
}
}
/* core impls */
impl<const V: $IP> Display for $name <V> {
fn fmt(&self, f: &mut Formatter) -> FmtResult<()> {
write!(f, "{}", self.get())
}
}
impl<const V: $IP> Debug for $name <V> {
fn fmt(&self, f: &mut Formatter) -> FmtResult<()> {
write!(f, "{}::<{}>({})", stringify!($name), V, self.get())
}
}
impl<const V: $IP> Binary for $name<V> {
fn fmt(&self, f: &mut Formatter) -> FmtResult<()> {
Binary::fmt(&self.get(), f)
}
}
impl<const V: $IP> Octal for $name<V> {
fn fmt(&self, f: &mut Formatter) -> FmtResult<()> {
Octal::fmt(&self.get(), f)
}
}
impl<const V: $IP> LowerHex for $name<V> {
fn fmt(&self, f: &mut Formatter) -> FmtResult<()> {
LowerHex::fmt(&self.get(), f)
}
}
impl<const V: $IP> UpperHex for $name<V> {
fn fmt(&self, f: &mut Formatter) -> FmtResult<()> {
UpperHex::fmt(&self.get(), f)
}
}
impl<const V: $IP> FromStr for $name<V> {
type Err = ParseIntError;
fn from_str(s: &str) -> Result<Self, Self::Err> {
Self::new($IP::from_str(s)?).ok_or_else(||"".parse::<i32>().unwrap_err())
}
}
/* conversions */
impl<const V: $IP> From<$name<V>> for $IP {
#[must_use]
fn from(value: $name<V>) -> $IP {
value.get()
}
}
impl<const V: $IP> TryFrom<$IP> for $name<V> {
type Error = $crate::TryFromIntError;
/// # Features
/// Makes use of the `unsafe_niche` feature if enabled.
fn try_from(value: $IP) -> Result<Self, Self::Error> {
// We generate a TryFromIntError by intentionally causing a failed conversion.
#[cfg(any(feature = "safe_num", not(feature = "unsafe_niche")))]
return Self::new(value).ok_or_else(|| i8::try_from(255_u8).unwrap_err());
#[cfg(all(not(feature = "safe_num"), feature = "unsafe_niche"))]
return Self::new(value)
.ok_or_else(|| unsafe { i8::try_from(255_u8).unwrap_err_unchecked() });
}
}
/* internal impls */
// BitSized
#[cfg(feature = "bit")]
impl<const V: $IP> BitSized<{$IP::BYTE_SIZE * 8}> for $name<V> {}
// NOTE: due to the orphan rule we can't implement MemPod for Option<NonValue*>
// #[cfg(feature = "unsafe_layout")]
// unsafe impl<const V: $IP> MemPod for Option<$name<V>> {}
/* external impls*/
#[cfg(all(feature = "dep_bytemuck", feature = "unsafe_niche", not(feature = "safe_num")))]
#[allow(non_snake_case)]
mod [<$name $s $b>] {
use super::*;
unsafe impl<const V: $IP> ZeroableInOption for $name<V> {}
unsafe impl<const V: $IP> PodInOption for $name<V> {}
unsafe impl<const V: $IP> NoUninit for $name<V> {}
unsafe impl<const V: $IP> CheckedBitPattern for $name<V> {
type Bits = $IP;
fn is_valid_bit_pattern(bits: &Self::Bits) -> bool {
// Since inner repr is NonZero, 0 is the only invalid bit pattern
*bits != 0
}
}
}
}
}};
}
#[doc(inline)]
pub use impl_non_value;