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macro_rules! uint_impl {
(
Self = $SelfT:ty,
ActualT = $ActualT:ident,
SignedT = $SignedT:ident,
NonZeroT = $NonZeroT:ident,
// 所有这些都*仅*在文档注释中使用。
// 因此,它们都作为字面量传递 -- 如果它们需要是多个代码 tokens,则将它们作为字符串字面量传递是好的。
//
// 在非注释中,使用关联的常量而不是这些。
BITS = $BITS:literal,
MAX = $MaxV:literal,
rot = $rot:literal,
rot_op = $rot_op:literal,
rot_result = $rot_result:literal,
swap_op = $swap_op:literal,
swapped = $swapped:literal,
reversed = $reversed:literal,
le_bytes = $le_bytes:literal,
be_bytes = $be_bytes:literal,
to_xe_bytes_doc = $to_xe_bytes_doc:expr,
from_xe_bytes_doc = $from_xe_bytes_doc:expr,
bound_condition = $bound_condition:literal,
) => {
/// 此整数类型可以表示的最小值。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN, 0);")]
/// ```
#[stable(feature = "assoc_int_consts", since = "1.43.0")]
pub const MIN: Self = 0;
/// 该整数类型可以表示的最大值
#[doc = concat!("(2<sup>", $BITS, "</sup> − 1", $bound_condition, ").")]
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX, ", stringify!($MaxV), ");")]
/// ```
#[stable(feature = "assoc_int_consts", since = "1.43.0")]
pub const MAX: Self = !0;
/// 此整数类型的大小 (以位为单位)。
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::BITS, ", stringify!($BITS), ");")]
/// ```
#[stable(feature = "int_bits_const", since = "1.53.0")]
pub const BITS: u32 = Self::MAX.count_ones();
/// 将给定基数的字符串切片转换为整数。
///
/// 该字符串应为可选的 `+` 符号,后跟数字。
///
/// 前导和尾随空格表示错误。
/// 根据 `radix`,数字是这些字符的子集:
///
/// * `0-9`
/// * `a-z`
/// * `A-Z`
///
/// # Panics
///
/// 如果 `radix` 不在 2 到 36 之间,则此函数 panics。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::from_str_radix(\"A\", 16), Ok(10));")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError> {
from_str_radix(src, radix)
}
/// 返回 `self` 二进制表示形式中的位数。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("let n = 0b01001100", stringify!($SelfT), ";")]
///
/// assert_eq!(n.count_ones(), 3);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[doc(alias = "popcount")]
#[doc(alias = "popcnt")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn count_ones(self) -> u32 {
intrinsics::ctpop(self as $ActualT) as u32
}
/// 返回 `self` 二进制表示形式中的零数。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.count_zeros(), 0);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn count_zeros(self) -> u32 {
(!self).count_ones()
}
/// 返回 `self` 二进制表示形式中前导零的数目。
///
/// 根据您对值的处理方式,您可能还对 [`ilog2`] 函数感兴趣,它返回一致的数字,即使类型变宽。
///
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("let n = ", stringify!($SelfT), "::MAX >> 2;")]
///
/// assert_eq!(n.leading_zeros(), 2);
/// ```
#[doc = concat!("[`ilog2`]: ", stringify!($SelfT), "::ilog2")]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn leading_zeros(self) -> u32 {
intrinsics::ctlz(self as $ActualT) as u32
}
/// 返回 `self` 二进制表示形式中的尾随零数。
///
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("let n = 0b0101000", stringify!($SelfT), ";")]
///
/// assert_eq!(n.trailing_zeros(), 3);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn trailing_zeros(self) -> u32 {
intrinsics::cttz(self) as u32
}
/// 返回 `self` 二进制表示形式中前导数字。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("let n = !(", stringify!($SelfT), "::MAX >> 2);")]
///
/// assert_eq!(n.leading_ones(), 2);
/// ```
#[stable(feature = "leading_trailing_ones", since = "1.46.0")]
#[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn leading_ones(self) -> u32 {
(!self).leading_zeros()
}
/// 返回 `self` 二进制表示形式中的尾随数字。
///
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("let n = 0b1010111", stringify!($SelfT), ";")]
///
/// assert_eq!(n.trailing_ones(), 3);
/// ```
#[stable(feature = "leading_trailing_ones", since = "1.46.0")]
#[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn trailing_ones(self) -> u32 {
(!self).trailing_zeros()
}
/// 将位左移指定的量 `n`,将截断的位包装到结果整数的末尾。
///
///
/// 请注意,此操作与 `<<` 移位运算符不同!
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("let n = ", $rot_op, stringify!($SelfT), ";")]
#[doc = concat!("let m = ", $rot_result, ";")]
///
#[doc = concat!("assert_eq!(n.rotate_left(", $rot, "), m);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn rotate_left(self, n: u32) -> Self {
intrinsics::rotate_left(self, n as $SelfT)
}
/// 将位右移指定的量 `n`,将截断的位包装到结果整数的开头。
///
///
/// 请注意,此操作与 `>>` 移位运算符不同!
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("let n = ", $rot_result, stringify!($SelfT), ";")]
#[doc = concat!("let m = ", $rot_op, ";")]
///
#[doc = concat!("assert_eq!(n.rotate_right(", $rot, "), m);")]
/// ```
///
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn rotate_right(self, n: u32) -> Self {
intrinsics::rotate_right(self, n as $SelfT)
}
/// 反转整数的字节顺序。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
/// let m = n.swap_bytes();
///
#[doc = concat!("assert_eq!(m, ", $swapped, ");")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn swap_bytes(self) -> Self {
intrinsics::bswap(self as $ActualT) as Self
}
/// 反转整数中的位顺序。
/// 最低有效位变为最高有效位,第二最低有效位变为第二最高有效位,依此类推。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
/// let m = n.reverse_bits();
///
#[doc = concat!("assert_eq!(m, ", $reversed, ");")]
#[doc = concat!("assert_eq!(0, 0", stringify!($SelfT), ".reverse_bits());")]
/// ```
#[stable(feature = "reverse_bits", since = "1.37.0")]
#[rustc_const_stable(feature = "reverse_bits", since = "1.37.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn reverse_bits(self) -> Self {
intrinsics::bitreverse(self as $ActualT) as Self
}
/// 将整数从大端字节序转换为目标的字节序。
///
/// 在大端节序序上,这是个禁忌。
/// 在小端字节序上,字节被交换。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
///
/// if cfg!(target_endian = "big") {
#[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n)")]
/// } else {
#[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n.swap_bytes())")]
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use]
#[inline(always)]
pub const fn from_be(x: Self) -> Self {
#[cfg(target_endian = "big")]
{
x
}
#[cfg(not(target_endian = "big"))]
{
x.swap_bytes()
}
}
/// 将整数从小端字节序转换为目标的字节序。
///
/// 在小端字节序上,这是个禁忌。
/// 在大字节序中,字节被交换。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
///
/// if cfg!(target_endian = "little") {
#[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n)")]
/// } else {
#[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n.swap_bytes())")]
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use]
#[inline(always)]
pub const fn from_le(x: Self) -> Self {
#[cfg(target_endian = "little")]
{
x
}
#[cfg(not(target_endian = "little"))]
{
x.swap_bytes()
}
}
/// 将 `self` 从目标的字节序转换为大字节序。
///
/// 在大端节序序上,这是个禁忌。
/// 在小端字节序上,字节被交换。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
///
/// if cfg!(target_endian = "big") {
/// assert_eq!(n.to_be(), n)
/// } else {
/// assert_eq!(n.to_be(), n.swap_bytes())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn to_be(self) -> Self { // 还是不是?
#[cfg(target_endian = "big")]
{
self
}
#[cfg(not(target_endian = "big"))]
{
self.swap_bytes()
}
}
/// 将 `self` 从目标的字节序转换为 Little Endian。
///
/// 在小端字节序上,这是个禁忌。
/// 在大字节序中,字节被交换。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
///
/// if cfg!(target_endian = "little") {
/// assert_eq!(n.to_le(), n)
/// } else {
/// assert_eq!(n.to_le(), n.swap_bytes())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn to_le(self) -> Self {
#[cfg(target_endian = "little")]
{
self
}
#[cfg(not(target_endian = "little"))]
{
self.swap_bytes()
}
}
/// 检查整数加法。
/// 计算 `self + rhs`,如果发生溢出则返回 `None`。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!(
"assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(1), ",
"Some(", stringify!($SelfT), "::MAX - 1));"
)]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_add(self, rhs: Self) -> Option<Self> {
let (a, b) = self.overflowing_add(rhs);
if unlikely!(b) {None} else {Some(a)}
}
/// 未经检查的整数加法。
/// 假设不会发生溢出,则计算 `self + rhs`。
///
/// # Safety
///
/// 当以下情况时,这导致未定义的行为
#[doc = concat!("`self + rhs > ", stringify!($SelfT), "::MAX` or `self + rhs < ", stringify!($SelfT), "::MIN`,")]
/// 即当 [`checked_add`] 将返回 `None` 时。
///
#[doc = concat!("[`checked_add`]: ", stringify!($SelfT), "::checked_add")]
#[unstable(
feature = "unchecked_math",
reason = "niche optimization path",
issue = "85122",
)]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[rustc_const_unstable(feature = "const_inherent_unchecked_arith", issue = "85122")]
#[inline(always)]
#[cfg_attr(miri, track_caller)] // 即使没有 panic,这也有助于 Miri 回溯
pub const unsafe fn unchecked_add(self, rhs: Self) -> Self {
// SAFETY: 调用者必须遵守 `unchecked_add` 的安全保证。
//
unsafe { intrinsics::unchecked_add(self, rhs) }
}
/// 用有符号整数检查加法。
/// 计算 `self + rhs`,如果发生溢出则返回 `None`。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(2), Some(3));")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(-2), None);")]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add_signed(3), None);")]
/// ```
#[stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_add_signed(self, rhs: $SignedT) -> Option<Self> {
let (a, b) = self.overflowing_add_signed(rhs);
if unlikely!(b) {None} else {Some(a)}
}
/// 检查整数减法。
/// 计算 `self - rhs`,如果发生溢出则返回 `None`。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub(1), Some(0));")]
#[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_sub(1), None);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_sub(self, rhs: Self) -> Option<Self> {
let (a, b) = self.overflowing_sub(rhs);
if unlikely!(b) {None} else {Some(a)}
}
/// 未经检查的整数减法。
/// 假设不会发生溢出,则计算 `self - rhs`。
///
/// # Safety
///
/// 当以下情况时,这导致未定义的行为
#[doc = concat!("`self - rhs > ", stringify!($SelfT), "::MAX` or `self - rhs < ", stringify!($SelfT), "::MIN`,")]
/// 即当 [`checked_sub`] 将返回 `None` 时。
///
#[doc = concat!("[`checked_sub`]: ", stringify!($SelfT), "::checked_sub")]
#[unstable(
feature = "unchecked_math",
reason = "niche optimization path",
issue = "85122",
)]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[rustc_const_unstable(feature = "const_inherent_unchecked_arith", issue = "85122")]
#[inline(always)]
#[cfg_attr(miri, track_caller)] // 即使没有 panic,这也有助于 Miri 回溯
pub const unsafe fn unchecked_sub(self, rhs: Self) -> Self {
// SAFETY: 调用者必须遵守 `unchecked_sub` 的安全保证。
//
unsafe { intrinsics::unchecked_sub(self, rhs) }
}
/// 检查整数乘法。
/// 计算 `self * rhs`,如果发生溢出则返回 `None`。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_mul(1), Some(5));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(2), None);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_mul(self, rhs: Self) -> Option<Self> {
let (a, b) = self.overflowing_mul(rhs);
if unlikely!(b) {None} else {Some(a)}
}
/// 未经检查的整数乘法。
/// 假设不会发生溢出,则计算 `self * rhs`。
///
/// # Safety
///
/// 当以下情况时,这导致未定义的行为
#[doc = concat!("`self * rhs > ", stringify!($SelfT), "::MAX` or `self * rhs < ", stringify!($SelfT), "::MIN`,")]
/// 即当 [`checked_mul`] 将返回 `None` 时。
///
#[doc = concat!("[`checked_mul`]: ", stringify!($SelfT), "::checked_mul")]
#[unstable(
feature = "unchecked_math",
reason = "niche optimization path",
issue = "85122",
)]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[rustc_const_unstable(feature = "const_inherent_unchecked_arith", issue = "85122")]
#[inline(always)]
#[cfg_attr(miri, track_caller)] // 即使没有 panic,这也有助于 Miri 回溯
pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self {
// SAFETY: 调用者必须遵守 `unchecked_mul` 的安全保证。
//
unsafe { intrinsics::unchecked_mul(self, rhs) }
}
/// 检查整数除法。
/// 计算 `self / rhs`,如果为 `rhs == 0`,则返回 `None`。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div(2), Some(64));")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div(0), None);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_div(self, rhs: Self) -> Option<Self> {
if unlikely!(rhs == 0) {
None
} else {
// SAFETY: 上面已经检查了 div 除以零的情况,并且无符号类型没有其他可用于除法的故障模式
//
Some(unsafe { intrinsics::unchecked_div(self, rhs) })
}
}
/// 检查欧几里得除法。
/// 计算 `self.div_euclid(rhs)`,如果为 `rhs == 0`,则返回 `None`。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div_euclid(2), Some(64));")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div_euclid(0), None);")]
/// ```
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> {
if unlikely!(rhs == 0) {
None
} else {
Some(self.div_euclid(rhs))
}
}
/// 检查整数余数。
/// 计算 `self % rhs`,如果为 `rhs == 0`,则返回 `None`。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(2), Some(1));")]
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None);")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
if unlikely!(rhs == 0) {
None
} else {
// SAFETY: 上面已经检查了 div 除以零的情况,并且无符号类型没有其他可用于除法的故障模式
//
Some(unsafe { intrinsics::unchecked_rem(self, rhs) })
}
}
/// 检查欧几里德模数。
/// 计算 `self.rem_euclid(rhs)`,如果为 `rhs == 0`,则返回 `None`。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(2), Some(1));")]
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None);")]
/// ```
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> {
if unlikely!(rhs == 0) {
None
} else {
Some(self.rem_euclid(rhs))
}
}
/// 返回数字相对于任意底数的对数,向下取整。
///
/// 由于实现细节,此方法可能未优化;
/// `ilog2` 可以更有效地产生以 2 为底的结果,而 `ilog10` 可以更有效地产生以 10 为底的结果。
///
///
/// # Panics
///
/// 如果 `self` 为零,或者如果 `base` 小于 2.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".ilog(5), 1);")]
/// ```
///
#[stable(feature = "int_log", since = "1.67.0")]
#[rustc_const_stable(feature = "int_log", since = "1.67.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn ilog(self, base: Self) -> u32 {
assert!(base >= 2, "base of integer logarithm must be at least 2");
if let Some(log) = self.checked_ilog(base) {
log
} else {
int_log10::panic_for_nonpositive_argument()
}
}
/// 返回数字的以 2 为底的对数,向下取整。
///
/// # Panics
///
/// 如果 `self` 为零,这个函数将会 panic。
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".ilog2(), 1);")]
/// ```
#[stable(feature = "int_log", since = "1.67.0")]
#[rustc_const_stable(feature = "int_log", since = "1.67.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn ilog2(self) -> u32 {
if let Some(log) = self.checked_ilog2() {
log
} else {
int_log10::panic_for_nonpositive_argument()
}
}
/// 返回数字的以 10 为底的对数,向下取整。
///
/// # Panics
///
/// 如果 `self` 为零,这个函数将会 panic。
///
/// # Example
///
/// ```
#[doc = concat!("assert_eq!(10", stringify!($SelfT), ".ilog10(), 1);")]
/// ```
#[stable(feature = "int_log", since = "1.67.0")]
#[rustc_const_stable(feature = "int_log", since = "1.67.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn ilog10(self) -> u32 {
if let Some(log) = self.checked_ilog10() {
log
} else {
int_log10::panic_for_nonpositive_argument()
}
}
/// 返回数字相对于任意底数的对数,向下取整。
///
/// 如果数字为零,或者基数不至少为零,则返回 `None` 2.
///
/// 由于实现细节,此方法可能未优化;
/// `checked_ilog2` 可以更有效地产生以 2 为底的结果,而 `checked_ilog10` 可以更有效地产生以 10 为底的结果。
///
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_ilog(5), Some(1));")]
/// ```
///
#[stable(feature = "int_log", since = "1.67.0")]
#[rustc_const_stable(feature = "int_log", since = "1.67.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_ilog(self, base: Self) -> Option<u32> {
if self <= 0 || base <= 1 {
None
} else {
let mut n = 0;
let mut r = self;
// 128 位宽整数的优化。
if Self::BITS == 128 {
let b = Self::ilog2(self) / (Self::ilog2(base) + 1);
n += b;
r /= base.pow(b as u32);
}
while r >= base {
r /= base;
n += 1;
}
Some(n)
}
}
/// 返回数字的以 2 为底的对数,向下取整。
///
/// 如果数字为零,则返回 `None`。
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_ilog2(), Some(1));")]
/// ```
#[stable(feature = "int_log", since = "1.67.0")]
#[rustc_const_stable(feature = "int_log", since = "1.67.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_ilog2(self) -> Option<u32> {
if let Some(x) = <$NonZeroT>::new(self) {
Some(x.ilog2())
} else {
None
}
}
/// 返回数字的以 10 为底的对数,向下取整。
///
/// 如果数字为零,则返回 `None`。
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_ilog10(), Some(1));")]
/// ```
#[stable(feature = "int_log", since = "1.67.0")]
#[rustc_const_stable(feature = "int_log", since = "1.67.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_ilog10(self) -> Option<u32> {
if let Some(x) = <$NonZeroT>::new(self) {
Some(x.ilog10())
} else {
None
}
}
/// 检查否定。
/// 计算 `-self`,除非 `self == 0`,否则返回 `None`。
///
/// 请注意,取反任何正整数将溢出。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_neg(), Some(0));")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_neg(), None);")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_neg(self) -> Option<Self> {
let (a, b) = self.overflowing_neg();
if unlikely!(b) {None} else {Some(a)}
}
/// 检查左移。
/// 计算 `self << rhs`,如果 `rhs` 大于或等于 `self` 中的位数,则返回 `None`。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(4), Some(0x10));")]
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(129), None);")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_shl(self, rhs: u32) -> Option<Self> {
let (a, b) = self.overflowing_shl(rhs);
if unlikely!(b) {None} else {Some(a)}
}
/// 未检查的左移。
/// 计算 `self << rhs`,假设 `rhs` 小于 `self` 中的位数。
///
/// # Safety
///
/// 如果 `rhs` 大于或等于 `self` 中的位数,则会导致未定义的行为,即
///
/// 当 [`checked_shl`] 返回 `None` 时。
///
#[doc = concat!("[`checked_shl`]: ", stringify!($SelfT), "::checked_shl")]
#[unstable(
feature = "unchecked_math",
reason = "niche optimization path",
issue = "85122",
)]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[rustc_const_unstable(feature = "const_inherent_unchecked_arith", issue = "85122")]
#[inline(always)]
#[cfg_attr(miri, track_caller)] // 即使没有 panic,这也有助于 Miri 回溯
pub const unsafe fn unchecked_shl(self, rhs: u32) -> Self {
// SAFETY: 调用者必须遵守 `unchecked_shl` 的安全保证。
//
// 任何合法的移位量都可以在自身类型中无损地表示。
unsafe { intrinsics::unchecked_shl(self, conv_rhs_for_unchecked_shift!($SelfT, rhs)) }
}
/// 检查右移。
/// 计算 `self >> rhs`,如果 `rhs` 大于或等于 `self` 中的位数,则返回 `None`。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(4), Some(0x1));")]
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(129), None);")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_shr(self, rhs: u32) -> Option<Self> {
let (a, b) = self.overflowing_shr(rhs);
if unlikely!(b) {None} else {Some(a)}
}
/// 未检查右移。
/// 计算 `self >> rhs`,假设 `rhs` 小于 `self` 中的位数。
///
/// # Safety
///
/// 如果 `rhs` 大于或等于 `self` 中的位数,则会导致未定义的行为,即
///
/// 当 [`checked_shr`] 返回 `None` 时。
///
#[doc = concat!("[`checked_shr`]: ", stringify!($SelfT), "::checked_shr")]
#[unstable(
feature = "unchecked_math",
reason = "niche optimization path",
issue = "85122",
)]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[rustc_const_unstable(feature = "const_inherent_unchecked_arith", issue = "85122")]
#[inline(always)]
#[cfg_attr(miri, track_caller)] // 即使没有 panic,这也有助于 Miri 回溯
pub const unsafe fn unchecked_shr(self, rhs: u32) -> Self {
// SAFETY: 调用者必须遵守 `unchecked_shr` 的安全保证。
//
// 任何合法的移位量都可以在自身类型中无损地表示。
unsafe { intrinsics::unchecked_shr(self, conv_rhs_for_unchecked_shift!($SelfT, rhs)) }
}
/// 检查取幂。
/// 计算 `self.pow(exp)`,如果发生溢出则返回 `None`。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_pow(5), Some(32));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);")]
/// ```
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
if exp == 0 {
return Some(1);
}
let mut base = self;
let mut acc: Self = 1;
while exp > 1 {
if (exp & 1) == 1 {
acc = try_opt!(acc.checked_mul(base));
}
exp /= 2;
base = try_opt!(base.checked_mul(base));
}
// 由于 exp!=0,最后 exp 必须是 1.
// 分开处理指数的最后一位,因为在此之后对底数进行平方是不必要的,并且可能导致不必要的溢出。
//
//
acc.checked_mul(base)
}
/// 饱和整数加法。
/// 计算 `self + rhs`,在数字范围内饱和,而不是溢出。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101);")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add(127), ", stringify!($SelfT), "::MAX);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
#[inline(always)]
pub const fn saturating_add(self, rhs: Self) -> Self {
intrinsics::saturating_add(self, rhs)
}
/// 带符号整数的饱和加法。
/// 计算 `self + rhs`,在数字范围内饱和,而不是溢出。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(2), 3);")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(-2), 0);")]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_add_signed(4), ", stringify!($SelfT), "::MAX);")]
/// ```
#[stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn saturating_add_signed(self, rhs: $SignedT) -> Self {
let (res, overflow) = self.overflowing_add(rhs as Self);
if overflow == (rhs < 0) {
res
} else if overflow {
Self::MAX
} else {
0
}
}
/// 饱和整数减法。
/// 计算 `self - rhs`,在数字范围内饱和,而不是溢出。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub(27), 73);")]
#[doc = concat!("assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
#[inline(always)]
pub const fn saturating_sub(self, rhs: Self) -> Self {
intrinsics::saturating_sub(self, rhs)
}
/// 饱和整数乘法。
/// 计算 `self * rhs`,在数字范围内饱和,而不是溢出。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".saturating_mul(10), 20);")]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX).saturating_mul(10), ", stringify!($SelfT),"::MAX);")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn saturating_mul(self, rhs: Self) -> Self {
match self.checked_mul(rhs) {
Some(x) => x,
None => Self::MAX,
}
}
/// 饱和整数除法。
/// 计算 `self / rhs`,在数值边界处饱和而不是溢出。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".saturating_div(2), 2);")]
///
/// ```
///
/// ```should_panic
#[doc = concat!("let _ = 1", stringify!($SelfT), ".saturating_div(0);")]
///
/// ```
#[stable(feature = "saturating_div", since = "1.58.0")]
#[rustc_const_stable(feature = "saturating_div", since = "1.58.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn saturating_div(self, rhs: Self) -> Self {
// 在无符号类型上,整数除法没有溢出
self.wrapping_div(rhs)
}
/// 饱和整数幂。
/// 计算 `self.pow(exp)`,在数字范围内饱和,而不是溢出。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(4", stringify!($SelfT), ".saturating_pow(3), 64);")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_pow(2), ", stringify!($SelfT), "::MAX);")]
/// ```
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn saturating_pow(self, exp: u32) -> Self {
match self.checked_pow(exp) {
Some(x) => x,
None => Self::MAX,
}
}
/// 包装 (modular) 添加。
/// 计算 `self + rhs`,在类型的边界处回绕。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(55), 255);")]
#[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(", stringify!($SelfT), "::MAX), 199);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_add(self, rhs: Self) -> Self {
intrinsics::wrapping_add(self, rhs)
}
/// 用有符号整数包装 (modular) 加法。
/// 计算 `self + rhs`,在类型的边界处回绕。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(2), 3);")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(-2), ", stringify!($SelfT), "::MAX);")]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_add_signed(4), 1);")]
/// ```
#[stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn wrapping_add_signed(self, rhs: $SignedT) -> Self {
self.wrapping_add(rhs as Self)
}
/// 包装 (modular) 减法。
/// 计算 `self - rhs`,在类型的边界处回绕。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(100), 0);")]
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(", stringify!($SelfT), "::MAX), 101);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_sub(self, rhs: Self) -> Self {
intrinsics::wrapping_sub(self, rhs)
}
/// 包装 (modular) 乘法。
/// 计算 `self * rhs`,在类型的边界处回绕。
///
/// # Examples
///
/// 基本用法:
///
/// 请注意,此示例在整数类型之间共享。
/// 这就解释了为什么在这里使用 `u8`。
///
/// ```
/// assert_eq!(10u8.wrapping_mul(12), 120);
/// assert_eq!(25u8.wrapping_mul(12), 44);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_mul(self, rhs: Self) -> Self {
intrinsics::wrapping_mul(self, rhs)
}
/// 包装 (modular) 分区。计算 `self / rhs`。
/// 无符号类型的包装除法只是普通除法。
/// 包装是不可能发生的。
/// 该函数存在,因此所有操作都在包装操作中考虑。
///
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div(10), 10);")]
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_div(self, rhs: Self) -> Self {
self / rhs
}
/// 包装欧几里得除法。计算 `self.div_euclid(rhs)`。
/// 无符号类型的包装除法只是普通除法。
/// 包装是不可能发生的。
/// 该函数存在,因此所有操作都在包装操作中考虑。
/// 因为对于正整数,所有除法的通用定义都是相等的,所以它恰好等于 `self.wrapping_div(rhs)`。
///
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div_euclid(10), 10);")]
/// ```
///
///
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_div_euclid(self, rhs: Self) -> Self {
self / rhs
}
/// 包装 (modular) 余数。计算 `self % rhs`。
/// 无符号类型的包装余数计算只是常规余数计算。
///
/// 包装是不可能发生的。
/// 该函数存在,因此所有操作都在包装操作中考虑。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem(10), 0);")]
/// ```
///
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_rem(self, rhs: Self) -> Self {
self % rhs
}
/// 包装欧几里德模。计算 `self.rem_euclid(rhs)`。
/// 无符号类型的包装模运算只是常规的余数计算。
/// 包装是不可能发生的。
/// 该函数存在,因此所有操作都在包装操作中考虑。
/// 因为对于正整数,所有除法的通用定义都是相等的,所以它恰好等于 `self.wrapping_rem(rhs)`。
///
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0);")]
/// ```
///
///
///
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_rem_euclid(self, rhs: Self) -> Self {
self % rhs
}
/// 包装 (modular) 取反。
/// 计算 `-self`,在类型的边界处回绕。
///
/// 由于无符号类型没有负的等效项,因此该函数的所有应用程序都将自动换行 (`-0` 除外)。
/// 对于小于相应有符号类型的最大值的值,结果与强制转换相应有符号值的结果相同。
///
/// 任何较大的值都等于 `MAX + 1 - (val - MAX - 1)`,其中 `MAX` 是对应的有符号类型的最大值。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".wrapping_neg(), 0);")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_neg(), 1);")]
#[doc = concat!("assert_eq!(13_", stringify!($SelfT), ".wrapping_neg(), (!13) + 1);")]
#[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_neg(), !(42 - 1));")]
/// ```
///
///
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_neg(self) -> Self {
(0 as $SelfT).wrapping_sub(self)
}
/// 无 Panic - 按位左移;
/// 产生 `self << mask(rhs)`,其中 `mask` 删除 `rhs` 的所有高位,这些高位将导致移位超过该类型的位宽。
///
/// 注意,这与左旋不同; 环绕左移的 RHS 限于该类型的范围,而不是从 LHS 移出的位返回到另一端。
/// 所有原始整数类型都实现了 [`rotate_left`](Self::rotate_left) 函数,而您可能想要的是 [`rotate_left`](Self::rotate_left) 函数。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_shl(7), 128);")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_shl(128), 1);")]
/// ```
///
///
///
///
///
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[rustc_allow_const_fn_unstable(const_inherent_unchecked_arith)]
pub const fn wrapping_shl(self, rhs: u32) -> Self {
// SAFETY: 通过类型的位大小进行掩蔽可确保我们不会越界
//
unsafe {
self.unchecked_shl(rhs & (Self::BITS - 1))
}
}
/// 无 Panic - 按位右移;
/// 产生 `self >> mask(rhs)`,其中 `mask` 删除 `rhs` 的所有高位,这些高位将导致移位超过该类型的位宽。
///
/// 注意,这与右旋转不同。换行右移的 RHS 限于类型的范围,而不是从 LHS 移出的位返回到另一端。
/// 所有原始整数类型都实现了 [`rotate_right`](Self::rotate_right) 函数,而您可能想要的是 [`rotate_right`](Self::rotate_right) 函数。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(128", stringify!($SelfT), ".wrapping_shr(7), 1);")]
#[doc = concat!("assert_eq!(128", stringify!($SelfT), ".wrapping_shr(128), 128);")]
/// ```
///
///
///
///
///
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[rustc_allow_const_fn_unstable(const_inherent_unchecked_arith)]
pub const fn wrapping_shr(self, rhs: u32) -> Self {
// SAFETY: 通过类型的位大小进行掩蔽可确保我们不会越界
//
unsafe {
self.unchecked_shr(rhs & (Self::BITS - 1))
}
}
/// 包装 (modular) 指数。
/// 计算 `self.pow(exp)`,在类型的边界处回绕。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_pow(5), 243);")]
/// assert_eq!(3u8.wrapping_pow(6), 217);
/// ```
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn wrapping_pow(self, mut exp: u32) -> Self {
if exp == 0 {
return 1;
}
let mut base = self;
let mut acc: Self = 1;
while exp > 1 {
if (exp & 1) == 1 {
acc = acc.wrapping_mul(base);
}
exp /= 2;
base = base.wrapping_mul(base);
}
// 由于 exp!=0,最后 exp 必须是 1.
// 分开处理指数的最后一位,因为在此之后对底数进行平方是不必要的,并且可能导致不必要的溢出。
//
//
acc.wrapping_mul(base)
}
/// 计算 `self` + `rhs`
///
/// 返回一个加法元组以及一个布尔值,该布尔值指示是否会发生算术溢出。
/// 如果将发生溢出,则返回包装的值。
///
/// # Examples
///
/// 基本用法
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_add(2), (7, false));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (0, true));")]
/// ```
///
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) {
let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT);
(a as Self, b)
}
/// 计算 `self` + `rhs` + `carry` 并返回一个包含总和和输出进位的元组。
///
/// 对两个整数操作数和一个进位位执行 "ternary addition",并返回一个输出整数和一个进位位。
/// 这允许将多个加法链接在一起以创建更广泛的加法,并且对于 bignum 加法很有用。
///
///
///
///
#[doc = concat!("This can be thought of as a ", stringify!($BITS), "-bit \"full adder\", in the electronics sense.")]
/// 如果输入进位为假,则此方法等价于 [`overflowing_add`](Self::overflowing_add),输出进位等于溢出标志。
/// 请注意,尽管进位和溢出标志对于无符号整数是相似的,但对于有符号整数它们是不同的。
///
/// # Examples
///
/// ```
/// #![feature(bigint_helper_methods)]
///
#[doc = concat!("// 3 MAX (a = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
#[doc = concat!("// + 5 7 (b = 5 × 2^", stringify!($BITS), " + 7)")]
/// // ---------
#[doc = concat!("// 9 6 (sum = 9 × 2^", stringify!($BITS), " + 6)")]
///
#[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (3, ", stringify!($SelfT), "::MAX);")]
#[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")]
/// let carry0 = false;
///
/// let (sum0, carry1) = a0.carrying_add(b0, carry0);
/// assert_eq!(carry1, true);
/// let (sum1, carry2) = a1.carrying_add(b1, carry1);
/// assert_eq!(carry2, false);
///
/// assert_eq!((sum1, sum0), (9, 6));
/// ```
///
///
///
///
#[unstable(feature = "bigint_helper_methods", issue = "85532")]
#[rustc_const_unstable(feature = "const_bigint_helper_methods", issue = "85532")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn carrying_add(self, rhs: Self, carry: bool) -> (Self, bool) {
// note: 从长远来看,这应该通过内部函数来完成,但目前已经证明这可以生成最佳代码,并且 LLVM 没有等效的内部函数
//
let (a, b) = self.overflowing_add(rhs);
let (c, d) = a.overflowing_add(carry as $SelfT);
(c, b || d)
}
/// 使用带符号的 `rhs` 计算 `self` + `rhs`
///
/// 返回一个加法元组以及一个布尔值,该布尔值指示是否会发生算术溢出。
/// 如果将发生溢出,则返回包装的值。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(2), (3, false));")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(-2), (", stringify!($SelfT), "::MAX, true));")]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_add_signed(4), (1, true));")]
/// ```
///
#[stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn overflowing_add_signed(self, rhs: $SignedT) -> (Self, bool) {
let (res, overflowed) = self.overflowing_add(rhs as Self);
(res, overflowed ^ (rhs < 0))
}
/// 计算 `self`-`rhs`
///
/// 返回一个减法的元组以及一个布尔值,该布尔值指示是否会发生算术溢出。
/// 如果将发生溢出,则返回包装的值。
///
/// # Examples
///
/// 基本用法
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_sub(2), (3, false));")]
#[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_sub(1), (", stringify!($SelfT), "::MAX, true));")]
/// ```
///
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT);
(a as Self, b)
}
/// 计算 `self`-`rhs`-`borrow` 并返回一个包含差值和输出借用的元组。
///
/// 通过从 `self` 中减去一个整数操作数和一个借用 - in 位来执行 "ternary subtraction",并返回一个输出整数和一个借用 - out 位。
/// 这允许将多个减法链接在一起以创建更广泛的减法,并且对于 bignum 减法很有用。
///
/// # Examples
///
/// ```
/// #![feature(bigint_helper_methods)]
///
#[doc = concat!("// 9 6 (a = 9 × 2^", stringify!($BITS), " + 6)")]
#[doc = concat!("// - 5 7 (b = 5 × 2^", stringify!($BITS), " + 7)")]
/// // ---------
#[doc = concat!("// 3 MAX (diff = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
///
#[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (9, 6);")]
#[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")]
/// let borrow0 = false;
///
/// let (diff0, borrow1) = a0.borrowing_sub(b0, borrow0);
/// assert_eq!(borrow1, true);
/// let (diff1, borrow2) = a1.borrowing_sub(b1, borrow1);
/// assert_eq!(borrow2, false);
///
#[doc = concat!("assert_eq!((diff1, diff0), (3, ", stringify!($SelfT), "::MAX));")]
/// ```
///
///
///
///
#[unstable(feature = "bigint_helper_methods", issue = "85532")]
#[rustc_const_unstable(feature = "const_bigint_helper_methods", issue = "85532")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn borrowing_sub(self, rhs: Self, borrow: bool) -> (Self, bool) {
// note: 从长远来看,这应该通过内部函数来完成,但目前已经证明这可以生成最佳代码,并且 LLVM 没有等效的内部函数
//
let (a, b) = self.overflowing_sub(rhs);
let (c, d) = a.overflowing_sub(borrow as $SelfT);
(c, b || d)
}
/// 计算 `self` 和 `other` 之间的绝对差。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(80), 20", stringify!($SelfT), ");")]
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(110), 10", stringify!($SelfT), ");")]
/// ```
#[stable(feature = "int_abs_diff", since = "1.60.0")]
#[rustc_const_stable(feature = "int_abs_diff", since = "1.60.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn abs_diff(self, other: Self) -> Self {
if mem::size_of::<Self>() == 1 {
// 当 SSE2 可用时,诱使 LLVM 生成 psadbw 指令,并且此函数为 u8 自动向量化。
//
(self as i32).wrapping_sub(other as i32).abs() as Self
} else {
if self < other {
other - self
} else {
self - other
}
}
}
/// 计算 `self` 和 `rhs` 的乘法。
///
/// 返回乘法的元组以及一个布尔值,该布尔值指示是否会发生算术溢出。
/// 如果将发生溢出,则返回包装的值。
///
/// # Examples
///
/// 基本用法:
///
/// 请注意,此示例在整数类型之间共享。
/// 这就解释了为什么在这里使用 `u32`。
///
/// ```
/// assert_eq!(5u32.overflowing_mul(2), (10, false));
/// assert_eq!(1_000_000_000u32.overflowing_mul(10), (1410065408, true));
/// ```
///
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT);
(a as Self, b)
}
/// `self` 除以 `rhs` 时计算除数。
///
/// 返回除数的元组以及指示是否将发生算术溢出的布尔值。
/// 请注意,对于无符号整数,永远不会发生溢出,因此第二个值始终为 `false`。
///
/// # Panics
///
/// 如果 `rhs` 是,这个函数会 panic 0.
///
/// # Examples
///
/// 基本用法
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div(2), (2, false));")]
/// ```
///
///
#[inline(always)]
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
pub const fn overflowing_div(self, rhs: Self) -> (Self, bool) {
(self / rhs, false)
}
/// 计算欧几里得除法 `self.div_euclid(rhs)` 的商。
///
/// 返回除数的元组以及指示是否将发生算术溢出的布尔值。
/// 请注意,对于无符号整数,永远不会发生溢出,因此第二个值始终为 `false`。
/// 因为对于正整数,所有除法的通用定义都是相等的,所以它恰好等于 `self.overflowing_div(rhs)`。
///
///
/// # Panics
///
/// 如果 `rhs` 是,这个函数会 panic 0.
///
/// # Examples
///
/// 基本用法
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div_euclid(2), (2, false));")]
/// ```
///
///
///
#[inline(always)]
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) {
(self / rhs, false)
}
/// `self` 除以 `rhs` 时计算余数。
///
/// 返回除法运算后的余数元组和一个布尔值,该布尔值指示是否会发生算术溢出。
/// 请注意,对于无符号整数,永远不会发生溢出,因此第二个值始终为 `false`。
///
/// # Panics
///
/// 如果 `rhs` 是,这个函数会 panic 0.
///
/// # Examples
///
/// 基本用法
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem(2), (1, false));")]
/// ```
///
///
#[inline(always)]
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
pub const fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
(self % rhs, false)
}
/// 以欧几里得除法计算余数 `self.rem_euclid(rhs)`。
///
/// 返回除以布尔后的模元,并返回一个布尔值,指示是否会发生算术溢出。
/// 请注意,对于无符号整数,永远不会发生溢出,因此第二个值始终为 `false`。
/// 由于对于正整数,所有除法的通用定义均相等,因此该运算恰好等于 `self.overflowing_rem(rhs)`。
///
///
/// # Panics
///
/// 如果 `rhs` 是,这个函数会 panic 0.
///
/// # Examples
///
/// 基本用法
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem_euclid(2), (1, false));")]
/// ```
///
///
///
#[inline(always)]
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) {
(self % rhs, false)
}
/// 以一种泛滥的方式否定自我。
///
/// 使用包装操作返回 `!self + 1`,以返回表示该无符号值的取反的值。
/// 请注意,对于正的无符号值,总是会发生溢出,但取反 0 不会溢出。
///
/// # Examples
///
/// 基本用法
///
/// ```
#[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_neg(), (0, false));")]
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2i32 as ", stringify!($SelfT), ", true));")]
/// ```
///
///
#[inline(always)]
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
pub const fn overflowing_neg(self) -> (Self, bool) {
((!self).wrapping_add(1), self != 0)
}
/// 将 self 左移 `rhs` 位。
///
/// 返回 self 的移位版本的元组以及一个布尔值,该布尔值指示 shift 值是否大于或等于位数。
/// 如果移位值太大,则将值屏蔽 (N-1),其中 N 是位数,然后使用该值执行移位。
///
/// # Examples
///
/// 基本用法
///
/// ```
#[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(4), (0x10, false));")]
#[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(132), (0x10, true));")]
/// ```
///
///
///
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
(self.wrapping_shl(rhs), rhs >= Self::BITS)
}
/// 将 self 右移 `rhs` 位。
///
/// 返回 self 的移位版本的元组以及一个布尔值,该布尔值指示 shift 值是否大于或等于位数。
/// 如果移位值太大,则将值屏蔽 (N-1),其中 N 是位数,然后使用该值执行移位。
///
/// # Examples
///
/// 基本用法
///
/// ```
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(4), (0x1, false));")]
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(132), (0x1, true));")]
/// ```
///
///
///
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
(self.wrapping_shr(rhs), rhs >= Self::BITS)
}
/// 通过平方运算,将自己提升到 `exp` 的功效。
///
/// 返回一个指数的元组以及一个 bool,指示是否发生了溢出。
///
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(3", stringify!($SelfT), ".overflowing_pow(5), (243, false));")]
/// assert_eq!(3u8.overflowing_pow(6), (217, true));
/// ```
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
if exp == 0{
return (1,false);
}
let mut base = self;
let mut acc: Self = 1;
let mut overflown = false;
// 暂存空间,用于存储 overflowing_mul 的结果。
let mut r;
while exp > 1 {
if (exp & 1) == 1 {
r = acc.overflowing_mul(base);
acc = r.0;
overflown |= r.1;
}
exp /= 2;
r = base.overflowing_mul(base);
base = r.0;
overflown |= r.1;
}
// 由于 exp!=0,最后 exp 必须是 1.
// 分开处理指数的最后一位,因为在此之后对底数进行平方是不必要的,并且可能导致不必要的溢出。
//
//
r = acc.overflowing_mul(base);
r.1 |= overflown;
r
}
/// 通过平方运算,将自己提升到 `exp` 的功效。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".pow(5), 32);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_inherit_overflow_checks]
pub const fn pow(self, mut exp: u32) -> Self {
if exp == 0 {
return 1;
}
let mut base = self;
let mut acc = 1;
while exp > 1 {
if (exp & 1) == 1 {
acc = acc * base;
}
exp /= 2;
base = base * base;
}
// 由于 exp!=0,最后 exp 必须是 1.
// 分开处理指数的最后一位,因为在此之后对底数进行平方是不必要的,并且可能导致不必要的溢出。
//
//
acc * base
}
/// 执行欧几里得除法。
///
/// 因为对于正整数,所有除法的通用定义都是相等的,所以它恰好等于 `self / rhs`。
///
///
/// # Panics
///
/// 如果 `rhs` 是,这个函数会 panic 0.
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(7", stringify!($SelfT), ".div_euclid(4), 1); // or any other integer type")]
/// ```
///
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[rustc_inherit_overflow_checks]
pub const fn div_euclid(self, rhs: Self) -> Self {
self / rhs
}
/// 计算 `self (mod rhs)` 的最小余数。
///
/// 因为对于正整数,所有除法的通用定义都是相等的,所以它恰好等于 `self % rhs`。
///
///
/// # Panics
///
/// 如果 `rhs` 是,这个函数会 panic 0.
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(7", stringify!($SelfT), ".rem_euclid(4), 3); // or any other integer type")]
/// ```
///
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[rustc_inherit_overflow_checks]
pub const fn rem_euclid(self, rhs: Self) -> Self {
self % rhs
}
/// 计算 `self` 和 `rhs` 的商,将结果四舍五入到负无穷大。
///
/// 这与对所有无符号整数执行 `self / rhs` 相同。
///
/// # Panics
///
/// 如果 `rhs` 为零,这个函数将会 panic。
///
/// # Examples
///
/// 基本用法:
///
/// ```
/// #![feature(int_roundings)]
#[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_floor(4), 1);")]
/// ```
#[unstable(feature = "int_roundings", issue = "88581")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn div_floor(self, rhs: Self) -> Self {
self / rhs
}
/// 计算 `self` 和 `rhs` 的商,将结果四舍五入到正无穷大。
///
/// # Panics
///
/// 如果 `rhs` 为零,这个函数将会 panic。
///
/// ## 溢出行为
///
/// 溢出时,如果启用溢出检查 (默认在调试模式下),此函数将 panic,如果禁用溢出检查 (默认在,生产模式,下),则返回。
///
///
/// # Examples
///
/// 基本用法:
///
/// ```
/// #![feature(int_roundings)]
#[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_ceil(4), 2);")]
/// ```
#[unstable(feature = "int_roundings", issue = "88581")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_inherit_overflow_checks]
pub const fn div_ceil(self, rhs: Self) -> Self {
let d = self / rhs;
let r = self % rhs;
if r > 0 && rhs > 0 {
d + 1
} else {
d
}
}
/// 计算大于或等于 `rhs` 倍数的 `self` 的最小值。
///
/// # Panics
///
/// 如果 `rhs` 为零,这个函数将会 panic。
///
/// ## 溢出行为
///
/// 溢出时,如果启用溢出检查 (默认在调试模式下),此函数将 panic,如果禁用溢出检查 (默认在,生产模式,下),则返回。
///
///
/// # Examples
///
/// 基本用法:
///
/// ```
/// #![feature(int_roundings)]
#[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(8), 16);")]
#[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(8), 24);")]
/// ```
///
#[unstable(feature = "int_roundings", issue = "88581")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_inherit_overflow_checks]
pub const fn next_multiple_of(self, rhs: Self) -> Self {
match self % rhs {
0 => self,
r => self + (rhs - r)
}
}
/// 计算大于或等于 `rhs` 倍数的 `self` 的最小值。
/// 如果 `rhs` 为零,则返回 `None`,否则操作会导致溢出。
///
/// # Examples
///
/// 基本用法:
///
/// ```
/// #![feature(int_roundings)]
#[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(16));")]
#[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(24));")]
#[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".checked_next_multiple_of(0), None);")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_multiple_of(2), None);")]
/// ```
///
#[unstable(feature = "int_roundings", issue = "88581")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_next_multiple_of(self, rhs: Self) -> Option<Self> {
match try_opt!(self.checked_rem(rhs)) {
0 => Some(self),
// rhs - r 不能溢出,因为 r 小于 rhs
r => self.checked_add(rhs - r)
}
}
/// 当且仅当某些 `k` 的 `self == 2^k` 时,才返回 `true`。
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert!(16", stringify!($SelfT), ".is_power_of_two());")]
#[doc = concat!("assert!(!10", stringify!($SelfT), ".is_power_of_two());")]
/// ```
#[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_is_power_of_two", since = "1.32.0")]
#[inline(always)]
pub const fn is_power_of_two(self) -> bool {
self.count_ones() == 1
}
// 返回比下一个 2 的幂小 1 的值。
// (对于 8u8,下一个 2 的幂为 8u8,对于 6u8 为 8u8)
//
// 8u8.one_less_than_next_power_of_two() == 7
// 6u8.one_less_than_next_power_of_two() == 7
//
// 此方法不会溢出,因为在 `next_power_of_two` 溢出情况下它最终会返回类型的最大值,并且可以返回 0 0.
//
//
#[inline]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
const fn one_less_than_next_power_of_two(self) -> Self {
if self <= 1 { return 0; }
let p = self - 1;
// SAFETY: 由于 `p > 0`,它不能完全由前导零组成。
// 这意味着移位始终是边界内的,并且当参数为非零值时,某些处理器 (例如 intel pre-haswell) 具有更高效的 ctlz 内部函数。
//
//
let z = unsafe { intrinsics::ctlz_nonzero(p) };
<$SelfT>::MAX >> z
}
/// 返回大于或等于 `self` 的 2 的最小幂。
///
/// 当返回值溢出 (即 `uN` 类型为 `self > (1 << (N-1))`) 时,它在调试模式下为 panics,在生产模式下返回值被包装为 0 (方法可以返回 0 的唯一情况)。
///
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".next_power_of_two(), 2);")]
#[doc = concat!("assert_eq!(3", stringify!($SelfT), ".next_power_of_two(), 4);")]
/// ```
///
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_inherit_overflow_checks]
pub const fn next_power_of_two(self) -> Self {
self.one_less_than_next_power_of_two() + 1
}
/// 返回大于或等于 `n` 的 2 的最小幂。
/// 如果下一个 2 的幂大于该类型的最大值,则返回 `None`,否则将 2 的幂包装在 `Some` 中。
///
///
/// # Examples
///
/// 基本用法:
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_next_power_of_two(), Some(2));")]
#[doc = concat!("assert_eq!(3", stringify!($SelfT), ".checked_next_power_of_two(), Some(4));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_power_of_two(), None);")]
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
pub const fn checked_next_power_of_two(self) -> Option<Self> {
self.one_less_than_next_power_of_two().checked_add(1)
}
/// 返回大于或等于 `n` 的 2 的最小幂。
/// 如果下一个 2 的幂大于该类型的最大值,则返回值将包装为 `0`。
///
///
/// # Examples
///
/// 基本用法:
///
/// ```
/// #![feature(wrapping_next_power_of_two)]
///
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".wrapping_next_power_of_two(), 2);")]
#[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_next_power_of_two(), 4);")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_next_power_of_two(), 0);")]
/// ```
#[inline]
#[unstable(feature = "wrapping_next_power_of_two", issue = "32463",
reason = "needs decision on wrapping behaviour")]
#[rustc_const_unstable(feature = "wrapping_next_power_of_two", issue = "32463")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
pub const fn wrapping_next_power_of_two(self) -> Self {
self.one_less_than_next_power_of_two().wrapping_add(1)
}
/// 以大端 (网络) 字节顺序将这个整数的内存表示形式作为字节数组返回。
///
///
#[doc = $to_xe_bytes_doc]
///
/// # Examples
///
/// ```
#[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_be_bytes();")]
#[doc = concat!("assert_eq!(bytes, ", $be_bytes, ");")]
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn to_be_bytes(self) -> [u8; mem::size_of::<Self>()] {
self.to_be().to_ne_bytes()
}
/// 以小端字节顺序将这个整数的内存表示形式返回为字节数组。
///
///
#[doc = $to_xe_bytes_doc]
///
/// # Examples
///
/// ```
#[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_le_bytes();")]
#[doc = concat!("assert_eq!(bytes, ", $le_bytes, ");")]
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn to_le_bytes(self) -> [u8; mem::size_of::<Self>()] {
self.to_le().to_ne_bytes()
}
/// 将此整数的内存表示作为本机字节顺序的字节数组返回。
///
/// 由于使用了目标平台的原生字节序,因此,可移植代码应酌情使用 [`to_be_bytes`] 或 [`to_le_bytes`]。
///
///
///
///
#[doc = $to_xe_bytes_doc]
///
/// [`to_be_bytes`]: Self::to_be_bytes
/// [`to_le_bytes`]: Self::to_le_bytes
///
/// # Examples
///
/// ```
#[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_ne_bytes();")]
/// assert_eq!(
/// bytes,
/// if cfg!(target_endian = "big") {
#[doc = concat!(" ", $be_bytes)]
/// } else {
#[doc = concat!(" ", $le_bytes)]
/// }
/// );
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
// SAFETY: const 之所以听起来不错,是因为整数是普通的旧数据类型,因此我们始终可以将它们转换为字节数组
//
#[inline]
pub const fn to_ne_bytes(self) -> [u8; mem::size_of::<Self>()] {
// SAFETY: 整数是普通的旧数据类型,因此我们始终可以将它们转换为字节数组
//
unsafe { mem::transmute(self) }
}
/// 根据其表示形式 (大字节序中的字节数组) 创建一个本地字节序整数值。
///
///
#[doc = $from_xe_bytes_doc]
///
/// # Examples
///
/// ```
#[doc = concat!("let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");")]
#[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
/// ```
///
/// 从切片而不是数组开始时,可以使用容易出错的转换 API:
///
/// ```
#[doc = concat!("fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
#[doc = concat!(" let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")]
/// *input = rest;
#[doc = concat!(" ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())")]
/// }
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
#[must_use]
#[inline]
pub const fn from_be_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self {
Self::from_be(Self::from_ne_bytes(bytes))
}
/// 从它的表示形式以 little endian 的字节数组创建一个本地 endian 整数值。
///
///
#[doc = $from_xe_bytes_doc]
///
/// # Examples
///
/// ```
#[doc = concat!("let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");")]
#[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
/// ```
///
/// 从切片而不是数组开始时,可以使用容易出错的转换 API:
///
/// ```
#[doc = concat!("fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
#[doc = concat!(" let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")]
/// *input = rest;
#[doc = concat!(" ", stringify!($SelfT), "::from_le_bytes(int_bytes.try_into().unwrap())")]
/// }
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
#[must_use]
#[inline]
pub const fn from_le_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self {
Self::from_le(Self::from_ne_bytes(bytes))
}
/// 从其内存表示形式以原生字节序形式创建一个原生字节序整数值。
///
/// 由于使用了目标平台的原生字节序,因此可移植代码可能希望酌情使用 [`from_be_bytes`] 或 [`from_le_bytes`]。
///
///
/// [`from_be_bytes`]: Self::from_be_bytes
/// [`from_le_bytes`]: Self::from_le_bytes
///
///
///
#[doc = $from_xe_bytes_doc]
///
/// # Examples
///
/// ```
#[doc = concat!("let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"big\") {")]
#[doc = concat!(" ", $be_bytes, "")]
/// } else {
#[doc = concat!(" ", $le_bytes, "")]
/// });
#[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
/// ```
///
/// 从切片而不是数组开始时,可以使用容易出错的转换 API:
///
/// ```
#[doc = concat!("fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
#[doc = concat!(" let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")]
/// *input = rest;
#[doc = concat!(" ", stringify!($SelfT), "::from_ne_bytes(int_bytes.try_into().unwrap())")]
/// }
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
#[must_use]
// SAFETY: const 之所以听起来不错,是因为整数是普通的旧数据类型,因此我们可以随时将其转换为整数
//
#[inline]
pub const fn from_ne_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self {
// SAFETY: 整数是普通的旧数据类型,因此我们可以随时将其转换为整数
unsafe { mem::transmute(bytes) }
}
/// 新代码应优先使用
#[doc = concat!("[`", stringify!($SelfT), "::MIN", "`] instead.")]
///
/// 返回此整数类型可以表示的最小值。
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_promotable]
#[inline(always)]
#[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
#[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on this type")]
pub const fn min_value() -> Self { Self::MIN }
/// 新代码应优先使用
#[doc = concat!("[`", stringify!($SelfT), "::MAX", "`] instead.")]
///
/// 返回此整数类型可以表示的最大值。
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_promotable]
#[inline(always)]
#[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
#[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on this type")]
pub const fn max_value() -> Self { Self::MAX }
}
}