1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474
use core::mem::{transmute_copy, ManuallyDrop};
/// Marker trait for types that can be represented as an unsigned integer.
///
/// A type that implements this trait is assumed to have the exact same memory
/// layout and representation as an unsigned integer, with the current compile
/// target's endianness. This implies a couple of useful properties:
///
/// * Casting between `T` and `T::Uint` is free and will (or should) be
/// optimized away.
/// * `[T]` can be cast to and from `[T::Uint]`.
///
/// This allows a number of common and useful optimizations, including casting
/// buffers and reusing memory. It does however come with some strict
/// requirements.
///
/// ## Safety
///
/// * The type must be inhabited (eg: no
/// [Infallible](std::convert::Infallible)).
/// * The type must allow any bit pattern (eg: either no requirements or some
/// ability to recover from invalid values).
/// * The type must be either a wrapper around `Self::Uint` or be safe to transmute to and from `Self::Uint`.
/// * The type must not contain any internal padding.
/// * The type must be `repr(C)` or `repr(transparent)`.
/// * The type must have the same size and alignment as `Self::Uint`.
///
/// Note also that the type is assumed to not implement `Drop`. This will
/// rarely, if ever, be an issue. The requirements above ensures that the
/// underlying field types stay the same and will be dropped.
pub unsafe trait UintCast {
/// An unsigned integer with the same size as `Self`.
type Uint;
}
/// Cast from a color type to an unsigned integer.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let color: PackedArgb = Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into();
/// assert_eq!(cast::into_uint(color), 0xFF17C64C);
/// ```
///
/// It's also possible to use `From` and `Into` when casting built-in types:
///
/// ```
/// use palette::Srgba;
///
/// let color = Srgba::new(23u8, 198, 76, 255);
///
/// // Integers implement `Into`:
/// let uint1: u32 = color.into();
///
/// // Integers implement `From`:
/// let uint2 = u32::from(color);
/// ```
#[inline]
pub fn into_uint<T>(color: T) -> T::Uint
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
// Safety: The requirements of implementing `UintCast`, as well as the size
// assert, ensures that transmuting `T` into `T::Uint` is safe.
unsafe { transmute_copy(&ManuallyDrop::new(color)) }
}
/// Cast from an unsigned integer to a color type.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let color: PackedArgb = Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into();
/// assert_eq!(cast::from_uint::<PackedArgb>(0xFF17C64C), color);
/// ```
///
/// It's also possible to use `From` and `Into` when casting built-in types:
///
/// ```
/// use palette::Srgba;
///
/// let uint = 0xFF17C64C;
///
/// // Integers implement `Into`:
/// let color1: Srgba<u8> = uint.into();
///
/// // Colors implement `From`:
/// let color2 = Srgba::from(uint);
/// ```
#[inline]
pub fn from_uint<T>(uint: T::Uint) -> T
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
// Safety: The requirements of implementing `UintCast`, as well as the size
// assert, ensures that transmuting `T::Uint` into `T` is safe.
unsafe { transmute_copy(&ManuallyDrop::new(uint)) }
}
/// Cast from a color type reference to an unsigned integer reference.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let color: PackedArgb = Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into();
/// assert_eq!(cast::into_uint_ref(&color), &0xFF17C64C);
/// ```
#[inline]
pub fn into_uint_ref<T>(value: &T) -> &T::Uint
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
assert_eq!(core::mem::align_of::<T::Uint>(), core::mem::align_of::<T>());
let value: *const T = value;
// Safety: The requirements of implementing `UintCast`, as well as the size
// and alignment asserts, ensures that reading `T` as `T::Uint` is safe.
unsafe { &*value.cast::<T::Uint>() }
}
/// Cast from an unsigned integer reference to a color type reference.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let color: PackedArgb = Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into();
/// assert_eq!(cast::from_uint_ref::<PackedArgb>(&0xFF17C64C), &color);
/// ```
#[inline]
pub fn from_uint_ref<T>(value: &T::Uint) -> &T
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
assert_eq!(core::mem::align_of::<T::Uint>(), core::mem::align_of::<T>());
let value: *const T::Uint = value;
// Safety: The requirements of implementing `UintCast`, as well as the size
// and alignment asserts, ensures that reading `T::Uint` as `T` is safe.
unsafe { &*value.cast::<T>() }
}
/// Cast from a mutable color type reference to a mutable unsigned integer reference.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let mut color: PackedArgb = Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into();
/// assert_eq!(cast::into_uint_mut(&mut color), &mut 0xFF17C64C);
/// ```
#[inline]
pub fn into_uint_mut<T>(value: &mut T) -> &mut T::Uint
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
assert_eq!(core::mem::align_of::<T::Uint>(), core::mem::align_of::<T>());
let value: *mut T = value;
// Safety: The requirements of implementing `UintCast`, as well as the size
// and alignment asserts, ensures that reading `T` as `T::Uint` is safe.
unsafe { &mut *value.cast::<T::Uint>() }
}
/// Cast from a mutable unsigned integer reference to a mutable color type reference.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let mut color: PackedArgb = Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into();
/// assert_eq!(cast::from_uint_mut::<PackedArgb>(&mut 0xFF17C64C), &mut color);
/// ```
#[inline]
pub fn from_uint_mut<T>(value: &mut T::Uint) -> &mut T
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
assert_eq!(core::mem::align_of::<T::Uint>(), core::mem::align_of::<T>());
let value: *mut T::Uint = value;
// Safety: The requirements of implementing `UintCast`, as well as the size
// and alignment asserts, ensures that reading `T::Uint` as `T` is safe.
unsafe { &mut *value.cast::<T>() }
}
/// Cast from an array of colors to an array of unsigned integers.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let colors: [PackedArgb; 2] = [
/// Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into(),
/// Srgba::new(0x5D, 0x12, 0xD6, 0xFF).into()
/// ];
/// assert_eq!(cast::into_uint_array(colors), [0xFF17C64C, 0xFF5D12D6])
/// ```
#[inline]
pub fn into_uint_array<T, const N: usize>(values: [T; N]) -> [T::Uint; N]
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
assert_eq!(core::mem::align_of::<T::Uint>(), core::mem::align_of::<T>());
// Safety: The requirements of implementing `UintCast`, as well as the size
// and alignment asserts, ensures transmuting `T` into `T::Uint` is safe.
// The length is the same because the size is the same.
unsafe { transmute_copy(&ManuallyDrop::new(values)) }
}
/// Cast from an array of unsigned integers to an array of colors.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let colors: [PackedArgb; 2] = [
/// Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into(),
/// Srgba::new(0x5D, 0x12, 0xD6, 0xFF).into()
/// ];
/// assert_eq!(cast::from_uint_array::<PackedArgb, 2>([0xFF17C64C, 0xFF5D12D6]), colors)
/// ```
#[inline]
pub fn from_uint_array<T, const N: usize>(values: [T::Uint; N]) -> [T; N]
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
assert_eq!(core::mem::align_of::<T::Uint>(), core::mem::align_of::<T>());
// Safety: The requirements of implementing `UintCast`, as well as the size
// and alignment asserts, ensures transmuting `T::Uint` into `T` is safe.
// The length is the same because the size is the same.
unsafe { transmute_copy(&ManuallyDrop::new(values)) }
}
/// Cast from a slice of colors to a slice of unsigned integers.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let colors: &[PackedArgb] = &[
/// Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into(),
/// Srgba::new(0x5D, 0x12, 0xD6, 0xFF).into()
/// ];
/// assert_eq!(cast::into_uint_slice(colors), &[0xFF17C64C, 0xFF5D12D6])
/// ```
#[inline]
pub fn into_uint_slice<T>(values: &[T]) -> &[T::Uint]
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
assert_eq!(core::mem::align_of::<T::Uint>(), core::mem::align_of::<T>());
// Safety: The requirements of implementing `UintCast`, as well as the size
// and alignment asserts, ensures that reading `T` as `T::Uint` is safe.
// The length is the same because the size is the same.
unsafe { core::slice::from_raw_parts(values.as_ptr().cast::<T::Uint>(), values.len()) }
}
/// Cast from a slice of unsigned integers to a slice of colors.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let colors: &[PackedArgb] = &[
/// Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into(),
/// Srgba::new(0x5D, 0x12, 0xD6, 0xFF).into()
/// ];
/// assert_eq!(cast::from_uint_slice::<PackedArgb>(&[0xFF17C64C, 0xFF5D12D6]), colors)
/// ```
#[inline]
pub fn from_uint_slice<T>(values: &[T::Uint]) -> &[T]
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
assert_eq!(core::mem::align_of::<T::Uint>(), core::mem::align_of::<T>());
// Safety: The requirements of implementing `UintCast`, as well as the size
// and alignment asserts, ensures that reading `T::Uint` as `T` is safe.
// The length is the same because the size is the same.
unsafe { core::slice::from_raw_parts(values.as_ptr().cast::<T>(), values.len()) }
}
/// Cast from a mutable slice of colors to a mutable slice of unsigned integers.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let colors: &mut [PackedArgb] = &mut [
/// Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into(),
/// Srgba::new(0x5D, 0x12, 0xD6, 0xFF).into()
/// ];
/// assert_eq!(cast::into_uint_slice_mut(colors), &mut [0xFF17C64C, 0xFF5D12D6])
/// ```
#[inline]
pub fn into_uint_slice_mut<T>(values: &mut [T]) -> &mut [T::Uint]
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
assert_eq!(core::mem::align_of::<T::Uint>(), core::mem::align_of::<T>());
// Safety: The requirements of implementing `UintCast`, as well as the size
// and alignment asserts, ensures that reading `T` as `T::Uint` is safe.
// The length is the same because the size is the same.
unsafe { core::slice::from_raw_parts_mut(values.as_mut_ptr().cast::<T::Uint>(), values.len()) }
}
/// Cast from a mutable slice of unsigned integers to a mutable slice of colors.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let colors: &mut [PackedArgb] = &mut [
/// Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into(),
/// Srgba::new(0x5D, 0x12, 0xD6, 0xFF).into()
/// ];
/// assert_eq!(cast::from_uint_slice_mut::<PackedArgb>(&mut [0xFF17C64C, 0xFF5D12D6]), colors)
/// ```
#[inline]
pub fn from_uint_slice_mut<T>(values: &mut [T::Uint]) -> &mut [T]
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
assert_eq!(core::mem::align_of::<T::Uint>(), core::mem::align_of::<T>());
// Safety: The requirements of implementing `UintCast`, as well as the size
// and alignment asserts, ensures that reading `T::Uint` as `T` is safe.
// The length is the same because the size is the same.
unsafe { core::slice::from_raw_parts_mut(values.as_mut_ptr().cast::<T>(), values.len()) }
}
/// Cast from a boxed slice of colors to a boxed slice of unsigned integers.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let colors: Box<[PackedArgb]> = vec![
/// Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into(),
/// Srgba::new(0x5D, 0x12, 0xD6, 0xFF).into()
/// ].into_boxed_slice();
///
/// assert_eq!(
/// cast::into_uint_slice_box(colors),
/// vec![0xFF17C64C, 0xFF5D12D6].into_boxed_slice()
/// )
/// ```
#[cfg(feature = "alloc")]
#[inline]
pub fn into_uint_slice_box<T>(values: alloc::boxed::Box<[T]>) -> alloc::boxed::Box<[T::Uint]>
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
assert_eq!(core::mem::align_of::<T::Uint>(), core::mem::align_of::<T>());
let raw: *mut [T::Uint] = into_uint_slice_mut(alloc::boxed::Box::leak(values));
// Safety: The requirements of implementing `UintCast`, as well as the size
// and alignment asserts, ensures that reading `T` as `T::Uint` is safe.
unsafe { alloc::boxed::Box::from_raw(raw) }
}
/// Cast from a boxed slice of unsigned integers to a boxed slice of colors.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let colors: Box<[PackedArgb]> = vec![
/// Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into(),
/// Srgba::new(0x5D, 0x12, 0xD6, 0xFF).into()
/// ].into_boxed_slice();
///
/// assert_eq!(
/// cast::from_uint_slice_box(vec![0xFF17C64C, 0xFF5D12D6].into_boxed_slice()),
/// colors
/// )
/// ```
#[cfg(feature = "alloc")]
#[inline]
pub fn from_uint_slice_box<T>(values: alloc::boxed::Box<[T::Uint]>) -> alloc::boxed::Box<[T]>
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
assert_eq!(core::mem::align_of::<T::Uint>(), core::mem::align_of::<T>());
let raw: *mut [T] = from_uint_slice_mut(alloc::boxed::Box::leak(values));
// Safety: The requirements of implementing `UintCast`, as well as the size
// and alignment asserts, ensures that reading `T::Uint` as `T` is safe.
unsafe { alloc::boxed::Box::from_raw(raw) }
}
/// Cast from a `Vec` of colors to a `Vec` of unsigned integers.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let colors: Vec<PackedArgb> = vec![
/// Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into(),
/// Srgba::new(0x5D, 0x12, 0xD6, 0xFF).into()
/// ];
///
/// assert_eq!(
/// cast::into_uint_vec(colors),
/// vec![0xFF17C64C, 0xFF5D12D6]
/// )
/// ```
#[cfg(feature = "alloc")]
#[inline]
pub fn into_uint_vec<T>(values: alloc::vec::Vec<T>) -> alloc::vec::Vec<T::Uint>
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
assert_eq!(core::mem::align_of::<T::Uint>(), core::mem::align_of::<T>());
let mut values = ManuallyDrop::new(values);
let raw = values.as_mut_ptr();
// Safety: The requirements of implementing `UintCast`, as well as the size
// and alignment asserts, ensures that reading `T` as `T::Uint` is safe.
// Length and capacity are the same because the size is the same.
unsafe {
alloc::vec::Vec::from_raw_parts(raw.cast::<T::Uint>(), values.len(), values.capacity())
}
}
/// Cast from a `Vec` of unsigned integers to a `Vec` of colors.
///
/// ```
/// use palette::{cast, rgb::PackedArgb, Srgba};
///
/// let colors: Vec<PackedArgb> = vec![
/// Srgba::new(0x17, 0xC6, 0x4C, 0xFF).into(),
/// Srgba::new(0x5D, 0x12, 0xD6, 0xFF).into()
/// ];
///
/// assert_eq!(
/// cast::from_uint_vec::<PackedArgb>(vec![0xFF17C64C, 0xFF5D12D6]),
/// colors
/// )
/// ```
#[cfg(feature = "alloc")]
#[inline]
pub fn from_uint_vec<T>(values: alloc::vec::Vec<T::Uint>) -> alloc::vec::Vec<T>
where
T: UintCast,
{
assert_eq!(core::mem::size_of::<T::Uint>(), core::mem::size_of::<T>());
assert_eq!(core::mem::align_of::<T::Uint>(), core::mem::align_of::<T>());
let mut values = ManuallyDrop::new(values);
let raw = values.as_mut_ptr();
// Safety: The requirements of implementing `UintCast`, as well as the size
// and alignment asserts, ensures that reading `T::Uint` as `T` is safe.
// Length and capacity are the same because the size is the same.
unsafe { alloc::vec::Vec::from_raw_parts(raw.cast::<T>(), values.len(), values.capacity()) }
}