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// cuadra::clamper
//
//!
//
#![allow(dead_code)]
/// Defines constant saturating casting functions between the permutations
/// of all the requested origin primitives and the destination primitives.
///
/// Some of the functions are redundant, and not all of them will be used.
macro_rules! scast {
(all_orig: $($orig:ty),+) => {
$( scast![all_dest: $orig; i8, u8, i16, u16, i32, u32, i64, u64, usize, isize]; )+
};
(all_dest: $orig:ty; $($dest:ty),+) => {
$( scast![single: $orig, $dest]; )+
};
(single: $orig:ty, $dest:ty) => {
paste::paste! {
#[doc = "Returns a saturating casted value from " $orig " to " $dest "."]
#[inline]
const fn [<cast_$orig _$dest>](orig: $orig) -> $dest {
// if casted != orig it can be either 0 or -1.
let casted = orig as $dest;
let overflow = orig != casted as $orig;
if overflow { if casted == 0 { $dest::MIN } else { $dest::MAX } } else { casted }
}
}
};
}
scast![all_orig: i8, u8, i16, u16, i32, u32, i64, u64, usize, isize];
/// Generates size-specific Clamper implementations.
macro_rules! macro_clamper {
($($ip:ty, $b:literal),+) => {
$( macro_clamper![single: $ip, $b]; )+
};
// $ip: inner primitive
// $b: bit size
(single: $ip:ty, $b:literal) => {
paste::paste! {
#[doc = "Clamps a distance to half the range of an [`" $ip "`]."]
///
/// It makes sure to clamp to the minimum or maximum representable
/// value in the new bit-size, under the new range-limit conditions.
pub struct [<Clamper$b>];
impl [<Clamper$b>] {
/// Minimum value for any layout dimension.
pub const MIN: $ip = $ip::MIN / 2;
/// Maximum value for any layout dimension.
pub const MAX: $ip = $ip::MAX / 2;
/* clamping from the same primitive */
#[doc = "Clamps [`" $ip "`] distance to [`MIN`][Self::MIN]`..`[`MAX`][Self::MAX]."]
///
/// This function clamps a value using the same primitive type.
///
/// It is simpler and probably faster than the other clamping
/// functions with the bit-size in the name.
#[inline(always)]
pub const fn clamp(d: $ip) -> $ip {
if d < Self::MIN {
Self::MIN
} else if d > Self::MAX {
Self::MAX
} else {
d
}
}
#[doc = "Clamps [`" $ip "`] distance to `0..`[`MAX`][Self::MAX]."]
///
/// This function clamps a value using the same primitive type.
///
/// It is simpler and probably faster than the other clamping
/// functions with the bit-size in the name.
#[inline]
pub const fn clamp_non_negative(d: $ip) -> $ip {
if d < 0 {
0
} else if d > Self::MAX {
Self::MAX
} else {
d
}
}
#[doc = "Clamps [`" $ip "`] distance to `1..`[`MAX`][Self::MAX]."]
///
/// This function clamps a value using the same primitive type.
///
/// It is simpler and probably faster than the other clamping
/// functions with the bit-size in the name.
#[inline]
pub const fn clamp_positive(d: $ip) -> $ip {
if d < 1 {
1
} else if d > Self::MAX {
Self::MAX
} else {
d
}
}
/* from/to i32*/
#[doc = "Clamps [`i32`] distance to [`" $ip "`] [`MIN`][Self::MIN]`..`[`MAX`][Self::MAX]."]
#[inline(always)]
pub const fn clamp_from_i32(d: i32) -> $ip {
[<cast_i32_$ip>](d)
}
#[doc = "Clamps [`i32`] distance to [`" $ip "`] `0..`[`MAX`][Self::MAX]."]
#[inline(always)]
pub const fn clamp_non_negative_from_i32(d: i32) -> $ip {
if d < 0 {
0
} else {
[<cast_i32_$ip>](d)
}
}
#[doc = "Clamps [`i32`] distance to [`" $ip "`] `1..`[`MAX`][Self::MAX]."]
#[inline(always)]
pub const fn clamp_positive_from_i32(d: i32) -> $ip {
if d < 1 {
1
} else {
[<cast_i32_$ip>](d)
}
}
//
#[doc = "Clamps [`" $ip "`] distance to [`i32`] [`MIN`][Self::MIN]`..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_to_i32(d: $ip) -> i32 {
if d < [<cast_i32_ $ip>](i32::MIN) {
i32::MIN
} else if d > [<cast_i32_ $ip>](i32::MAX) {
i32::MAX
} else {
[<cast_$ip _i32>](d)
}
}
#[doc = "Clamps [`" $ip "`] distance to [`i32`] `0..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_non_negative_to_i32(d: $ip) -> i32 {
if d < 0 {
0
} else if d > [<cast_i32_ $ip>](i32::MAX) {
i32::MAX
} else {
[<cast_$ip _i32>](d)
}
}
#[doc = "Clamps [`" $ip "`] distance to [`i32`] `1..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_positive_to_i32(d: $ip) -> i32 {
if d < 1 {
1
} else if d > [<cast_i32_ $ip>](i32::MAX) {
i32::MAX
} else {
[<cast_$ip _i32>](d)
}
}
/* from/to u32 (e.g. notcurses, tiny-skia)*/
#[doc = "Clamps an [`u32`] distance to [`" $ip "`] `0..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_from_u32(d: u32) -> $ip {
if d > [<cast_$ip _u32>](Self::MAX) {
Self::MAX
} else {
[<cast_u32_$ip>](d)
}
}
#[doc = "Clamps [`u32`] distance to [`" $ip "`] `1..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_positive_from_u32(d: u32) -> $ip {
if d == 0 {
1
} else if d > [<cast_$ip _u32>](Self::MAX) {
Self::MAX
} else {
[<cast_u32_$ip>](d)
}
}
//
#[doc = "Clamps [`" $ip "`] distance to [`u32`] `0..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_to_u32(d: $ip) -> u32 {
[<cast _$ip _u32>](Self::clamp_non_negative(d))
}
#[doc = "Clamps [`" $ip "`] distance to [`u32`] `1..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_positive_to_u32(d: $ip) -> u32 {
[<cast _$ip _u32>](Self::clamp_positive(d))
}
/* from/to u16 (e.g. crossterm) */
#[doc = "Clamps [`u16`] distance to [`" $ip "`] `0..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_from_u16(d: u16) -> $ip {
if d > [<cast_$ip _u16>](Self::MAX) {
Self::MAX
} else {
[<cast_u16_$ip>](d)
}
}
#[doc = "Clamps [`u16`] distance to [`" $ip "`] `1..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_positive_from_u16(d: u16) -> $ip {
if d == 0 {
1
} else if d > [<cast_$ip _u16>](Self::MAX) {
Self::MAX
} else {
[<cast_u16_$ip>](d)
}
}
//
#[doc = "Clamps [`" $ip "`] distance to [`u16`] `0..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_to_u16(d: $ip) -> u16 {
if d < 0 {
0
} else if d > [<cast_u16_ $ip>](u16::MAX) {
u16::MAX
} else {
[<cast_$ip _u16>](d)
}
}
#[doc = "Clamps [`" $ip "`] distance to [`u16`] `1..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_positive_to_u16(d: $ip) -> u16 {
if d < 1 {
1
} else if d > [<cast_u16_ $ip>](u16::MAX) {
u16::MAX
} else {
[<cast_$ip _u16>](d)
}
}
/* from/to i16 (e.g. sdl) */
#[doc = "Clamps [`i16`] distance to [`" $ip "`] [`MIN`][Self::MIN]`..`[`MAX`][Self::MAX]."]
#[inline(always)]
pub const fn clamp_from_i16(d: i16) -> $ip {
[<cast_i16_$ip>](d)
}
#[doc = "Clamps [`i16`] distance to [`" $ip "`] `0..`[`MAX`][Self::MAX]."]
#[inline(always)]
pub const fn clamp_non_negative_from_i16(d: i16) -> $ip {
if d < 0 {
0
} else {
[<cast_i16_$ip>](d)
}
}
#[doc = "Clamps [`i16`] distance to [`" $ip "`] `1..`[`MAX`][Self::MAX]."]
#[inline(always)]
pub const fn clamp_positive_from_i16(d: i16) -> $ip {
if d < 1 {
1
} else {
[<cast_i16_$ip>](d)
}
}
//
#[doc = "Clamps [`" $ip "`] distance to [`i16`] [`MIN`][Self::MIN]`..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_to_i16(d: $ip) -> i16 {
if d < [<cast_i16_ $ip>](i16::MIN) {
i16::MIN
} else if d > [<cast_i16_ $ip>](i16::MAX) {
i16::MAX
} else {
[<cast_$ip _i16>](d)
}
}
#[doc = "Clamps [`" $ip "`] distance to [`i16`] `0..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_non_negative_to_i16(d: $ip) -> i16 {
if d < 0 {
0
} else if d > [<cast_i16_ $ip>](i16::MAX) {
i16::MAX
} else {
[<cast_$ip _i16>](d)
}
}
#[doc = "Clamps [`" $ip "`] distance to [`i16`] `1..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_positive_to_i16(d: $ip) -> i16 {
if d < 1 {
1
} else if d > [<cast_i16_ $ip>](i16::MAX) {
i16::MAX
} else {
[<cast_$ip _i16>](d)
}
}
/* from/to usize (e.g. machine word size & slice len)*/
#[doc = "Clamps [`usize`] distance to [`" $ip "`] `0..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_from_usize(d: usize) -> $ip {
if d > [<cast_$ip _usize>](Self::MAX) {
Self::MAX
} else {
[<cast_usize_$ip>](d)
}
}
#[doc = "Clamps [`usize`] distance to [`" $ip "`] `1..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_positive_from_usize(d: usize) -> $ip {
if d == 0 {
1
} else if d > [<cast_$ip _usize>](Self::MAX) {
Self::MAX
} else {
[<cast_usize_$ip>](d)
}
}
//
#[doc = "Clamps [`" $ip "`] distance to [`usize`] `0..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_to_usize(d: $ip) -> usize {
[<cast_$ip _usize>](Self::clamp_non_negative(d))
}
#[doc = "Clamps [`" $ip "`] distance to [`usize`] `1..`[`MAX`][Self::MAX]."]
#[inline]
pub const fn clamp_positive_to_usize(d: $ip) -> usize {
[<cast_$ip _usize>](Self::clamp_positive(d))
}
}
}
};
}
macro_clamper![i8, 8, i16, 16, i32, 32, i64, 64];