当前位置： 首页 > news >正文

石家庄新华区网站建设百度seo排名优化公司

news 2025/8/9 17:16:56
石家庄新华区网站建设,百度seo排名优化公司,洞口做网站,公司网站建设费用怎么记账这段代码定义了一个泛型结构体 Length<T, Unit>&#xff0c;用于表示一维长度&#xff0c;其中 T 表示长度的数值类型&#xff0c;而 Unit 是一个编译时检查单位一致性的占位符类型&#xff0c;不会用于运行时表示长度的值。这个设计允许开发者在编译阶段确保不同单位之间…

这段代码定义了一个泛型结构体 Length<T, Unit>，用于表示一维长度，其中 T 表示长度的数值类型，而 Unit 是一个编译时检查单位一致性的占位符类型，不会用于运行时表示长度的值。这个设计允许开发者在编译阶段确保不同单位之间的长度值在使用前进行了显式的单位转换。

一、length.rs文件源码

//! 用计量单位标记的一维长度。use crate::approxeq::ApproxEq;
use crate::approxord::{max, min};
use crate::num::Zero;
use crate::scale::Scale;use crate::num::One;
#[cfg(feature = "bytemuck")]
use bytemuck::{Pod, Zeroable};
use core::cmp::Ordering;
use core::fmt;
use core::hash::{Hash, Hasher};
use core::iter::Sum;
use core::marker::PhantomData;
use core::ops::{Add, Div, Mul, Neg, Sub};
use core::ops::{AddAssign, DivAssign, MulAssign, SubAssign};
use num_traits::{NumCast, Saturating};
#[cfg(feature = "serde")]
use serde::{Deserialize, Deserializer, Serialize, Serializer};/*
一维距离，其值由“T”表示，测量单位为“Unit”。 
“T”可以是任何数字类型，例如像“u64”或“f32”这样的基元类型。 
“Unit”不用于表示“Length”值。它仅在编译时使用，以确保用一个单位存储的“Length”在用于需要不同单位的表达式之前被显式转换。它可能是一个没有值的类型，例如空枚举。 
您可以将“Length”乘以“Scale”，将其从一个单位转换为另一个单位。请参阅[`Scale`]结构体。
*/
#[repr(C)]
pub struct Length<T, Unit>(pub T, #[doc(hidden)] pub PhantomData<Unit>);impl<T: Clone, U> Clone for Length<T, U> {fn clone(&self) -> Self {Length(self.0.clone(), PhantomData)}
}impl<T: Copy, U> Copy for Length<T, U> {}#[cfg(feature = "serde")]
impl<'de, T, U> Deserialize<'de> for Length<T, U> where T: Deserialize<'de>,{fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> where D: Deserializer<'de>,{Ok(Length(Deserialize::deserialize(deserializer)?, PhantomData))}
}#[cfg(feature = "serde")]
impl<T, U> Serialize for Length<T, U> where T: Serialize,{fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> where S: Serializer,{self.0.serialize(serializer)}
}#[cfg(feature = "arbitrary")]
impl<'a, T, U> arbitrary::Arbitrary<'a> for Length<T, U>
whereT: arbitrary::Arbitrary<'a>,
{fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {Ok(Length(arbitrary::Arbitrary::arbitrary(u)?, PhantomData))}
}#[cfg(feature = "bytemuck")]
unsafe impl<T: Zeroable, U> Zeroable for Length<T, U> {}#[cfg(feature = "bytemuck")]
unsafe impl<T: Pod, U: 'static> Pod for Length<T, U> {}impl<T, U> Length<T, U> {/// 将值与度量单位相关联。#[inline]pub const fn new(x: T) -> Self {Length(x, PhantomData)}
}impl<T: Clone, U> Length<T, U> {/// 从类中提取基值pub fn get(self) -> T {self.0}/// Cast the unit#[inline]pub fn cast_unit<V>(self) -> Length<T, V> {Length::new(self.0)}/// Linearly interpolate between this length and another length.////// # Example////// ```rust/// use euclid::default::Length;////// let from = Length::new(0.0);/// let to = Length::new(8.0);////// assert_eq!(from.lerp(to, -1.0), Length::new(-8.0));/// assert_eq!(from.lerp(to,  0.0), Length::new( 0.0));/// assert_eq!(from.lerp(to,  0.5), Length::new( 4.0));/// assert_eq!(from.lerp(to,  1.0), Length::new( 8.0));/// assert_eq!(from.lerp(to,  2.0), Length::new(16.0));/// ```#[inline]pub fn lerp(self, other: Self, t: T) -> SelfwhereT: One + Sub<Output = T> + Mul<Output = T> + Add<Output = T>,{let one_t = T::one() - t.clone();Length::new(one_t * self.0.clone() + t * other.0)}
}impl<T: PartialOrd, U> Length<T, U> {/// Returns minimum between this length and another length.#[inline]pub fn min(self, other: Self) -> Self {min(self, other)}/// Returns maximum between this length and another length.#[inline]pub fn max(self, other: Self) -> Self {max(self, other)}
}impl<T: NumCast + Clone, U> Length<T, U> {/// Cast from one numeric representation to another, preserving the units.#[inline]pub fn cast<NewT: NumCast>(self) -> Length<NewT, U> {self.try_cast().unwrap()}/// Fallible cast from one numeric representation to another, preserving the units.pub fn try_cast<NewT: NumCast>(self) -> Option<Length<NewT, U>> {NumCast::from(self.0).map(Length::new)}
}impl<T: fmt::Debug, U> fmt::Debug for Length<T, U> {fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {self.0.fmt(f)}
}impl<T: Default, U> Default for Length<T, U> {#[inline]fn default() -> Self {Length::new(Default::default())}
}impl<T: Hash, U> Hash for Length<T, U> {fn hash<H: Hasher>(&self, h: &mut H) {self.0.hash(h);}
}// length + length
impl<T: Add, U> Add for Length<T, U> {type Output = Length<T::Output, U>;fn add(self, other: Self) -> Self::Output {Length::new(self.0 + other.0)}
}// length + &length
impl<T: Add + Copy, U> Add<&Self> for Length<T, U> {type Output = Length<T::Output, U>;fn add(self, other: &Self) -> Self::Output {Length::new(self.0 + other.0)}
}// length_iter.copied().sum()
impl<T: Add<Output = T> + Zero, U> Sum for Length<T, U> {fn sum<I: Iterator<Item = Self>>(iter: I) -> Self {iter.fold(Self::zero(), Add::add)}
}// length_iter.sum()
impl<'a, T: 'a + Add<Output = T> + Copy + Zero, U: 'a> Sum<&'a Self> for Length<T, U> {fn sum<I: Iterator<Item = &'a Self>>(iter: I) -> Self {iter.fold(Self::zero(), Add::add)}
}// length += length
impl<T: AddAssign, U> AddAssign for Length<T, U> {fn add_assign(&mut self, other: Self) {self.0 += other.0;}
}// length - length
impl<T: Sub, U> Sub for Length<T, U> {type Output = Length<T::Output, U>;fn sub(self, other: Length<T, U>) -> Self::Output {Length::new(self.0 - other.0)}
}// length -= length
impl<T: SubAssign, U> SubAssign for Length<T, U> {fn sub_assign(&mut self, other: Self) {self.0 -= other.0;}
}// Saturating length + length and length - length.
impl<T: Saturating, U> Saturating for Length<T, U> {fn saturating_add(self, other: Self) -> Self {Length::new(self.0.saturating_add(other.0))}fn saturating_sub(self, other: Self) -> Self {Length::new(self.0.saturating_sub(other.0))}
}// length / length
impl<Src, Dst, T: Div> Div<Length<T, Src>> for Length<T, Dst> {type Output = Scale<T::Output, Src, Dst>;#[inline]fn div(self, other: Length<T, Src>) -> Self::Output {Scale::new(self.0 / other.0)}
}// length * scalar
impl<T: Mul, U> Mul<T> for Length<T, U> {type Output = Length<T::Output, U>;#[inline]fn mul(self, scale: T) -> Self::Output {Length::new(self.0 * scale)}
}// length *= scalar
impl<T: Copy + Mul<T, Output = T>, U> MulAssign<T> for Length<T, U> {#[inline]fn mul_assign(&mut self, scale: T) {*self = *self * scale;}
}// length / scalar
impl<T: Div, U> Div<T> for Length<T, U> {type Output = Length<T::Output, U>;#[inline]fn div(self, scale: T) -> Self::Output {Length::new(self.0 / scale)}
}// length /= scalar
impl<T: Copy + Div<T, Output = T>, U> DivAssign<T> for Length<T, U> {#[inline]fn div_assign(&mut self, scale: T) {*self = *self / scale;}
}// length * scaleFactor
impl<Src, Dst, T: Mul> Mul<Scale<T, Src, Dst>> for Length<T, Src> {type Output = Length<T::Output, Dst>;#[inline]fn mul(self, scale: Scale<T, Src, Dst>) -> Self::Output {Length::new(self.0 * scale.0)}
}// length / scaleFactor
impl<Src, Dst, T: Div> Div<Scale<T, Src, Dst>> for Length<T, Dst> {type Output = Length<T::Output, Src>;#[inline]fn div(self, scale: Scale<T, Src, Dst>) -> Self::Output {Length::new(self.0 / scale.0)}
}// -length
impl<U, T: Neg> Neg for Length<T, U> {type Output = Length<T::Output, U>;#[inline]fn neg(self) -> Self::Output {Length::new(-self.0)}
}impl<T: PartialEq, U> PartialEq for Length<T, U> {fn eq(&self, other: &Self) -> bool {self.0.eq(&other.0)}
}impl<T: PartialOrd, U> PartialOrd for Length<T, U> {fn partial_cmp(&self, other: &Self) -> Option<Ordering> {self.0.partial_cmp(&other.0)}
}impl<T: Eq, U> Eq for Length<T, U> {}impl<T: Ord, U> Ord for Length<T, U> {fn cmp(&self, other: &Self) -> Ordering {self.0.cmp(&other.0)}
}impl<T: Zero, U> Zero for Length<T, U> {#[inline]fn zero() -> Self {Length::new(Zero::zero())}
}impl<U, T: ApproxEq<T>> ApproxEq<T> for Length<T, U> {#[inline]fn approx_epsilon() -> T {T::approx_epsilon()}#[inline]fn approx_eq_eps(&self, other: &Length<T, U>, approx_epsilon: &T) -> bool {self.0.approx_eq_eps(&other.0, approx_epsilon)}
}#[cfg(test)]
mod tests {use super::Length;use crate::num::Zero;use crate::scale::Scale;use core::f32::INFINITY;use num_traits::Saturating;enum Inch {}enum Mm {}enum Cm {}enum Second {}#[cfg(feature = "serde")]mod serde {use super::*;extern crate serde_test;use self::serde_test::assert_tokens;use self::serde_test::Token;#[test]fn test_length_serde() {let one_cm: Length<f32, Mm> = Length::new(10.0);assert_tokens(&one_cm, &[Token::F32(10.0)]);}}#[test]fn test_clone() {// A cloned Length is a separate length with the state matching the// original Length at the point it was cloned.let mut variable_length: Length<f32, Inch> = Length::new(12.0);let one_foot = variable_length.clone();variable_length.0 = 24.0;assert_eq!(one_foot.get(), 12.0);assert_eq!(variable_length.get(), 24.0);}#[test]fn test_add() {let length1: Length<u8, Mm> = Length::new(250);let length2: Length<u8, Mm> = Length::new(5);assert_eq!((length1 + length2).get(), 255);assert_eq!((length1 + &length2).get(), 255);}#[test]fn test_sum() {type L = Length<f32, Mm>;let lengths = [L::new(1.0), L::new(2.0), L::new(3.0)];assert_eq!(lengths.iter().sum::<L>(), L::new(6.0));}#[test]fn test_addassign() {let one_cm: Length<f32, Mm> = Length::new(10.0);let mut measurement: Length<f32, Mm> = Length::new(5.0);measurement += one_cm;assert_eq!(measurement.get(), 15.0);}#[test]fn test_sub() {let length1: Length<u8, Mm> = Length::new(250);let length2: Length<u8, Mm> = Length::new(5);let result = length1 - length2;assert_eq!(result.get(), 245);}#[test]fn test_subassign() {let one_cm: Length<f32, Mm> = Length::new(10.0);let mut measurement: Length<f32, Mm> = Length::new(5.0);measurement -= one_cm;assert_eq!(measurement.get(), -5.0);}#[test]fn test_saturating_add() {let length1: Length<u8, Mm> = Length::new(250);let length2: Length<u8, Mm> = Length::new(6);let result = length1.saturating_add(length2);assert_eq!(result.get(), 255);}#[test]fn test_saturating_sub() {let length1: Length<u8, Mm> = Length::new(5);let length2: Length<u8, Mm> = Length::new(10);let result = length1.saturating_sub(length2);assert_eq!(result.get(), 0);}#[test]fn test_division_by_length() {// Division results in a Scale from denominator units// to numerator units.let length: Length<f32, Cm> = Length::new(5.0);let duration: Length<f32, Second> = Length::new(10.0);let result = length / duration;let expected: Scale<f32, Second, Cm> = Scale::new(0.5);assert_eq!(result, expected);}#[test]fn test_multiplication() {let length_mm: Length<f32, Mm> = Length::new(10.0);let cm_per_mm: Scale<f32, Mm, Cm> = Scale::new(0.1);let result = length_mm * cm_per_mm;let expected: Length<f32, Cm> = Length::new(1.0);assert_eq!(result, expected);}#[test]fn test_multiplication_with_scalar() {let length_mm: Length<f32, Mm> = Length::new(10.0);let result = length_mm * 2.0;let expected: Length<f32, Mm> = Length::new(20.0);assert_eq!(result, expected);}#[test]fn test_multiplication_assignment() {let mut length: Length<f32, Mm> = Length::new(10.0);length *= 2.0;let expected: Length<f32, Mm> = Length::new(20.0);assert_eq!(length, expected);}#[test]fn test_division_by_scalefactor() {let length: Length<f32, Cm> = Length::new(5.0);let cm_per_second: Scale<f32, Second, Cm> = Scale::new(10.0);let result = length / cm_per_second;let expected: Length<f32, Second> = Length::new(0.5);assert_eq!(result, expected);}#[test]fn test_division_by_scalar() {let length: Length<f32, Cm> = Length::new(5.0);let result = length / 2.0;let expected: Length<f32, Cm> = Length::new(2.5);assert_eq!(result, expected);}#[test]fn test_division_assignment() {let mut length: Length<f32, Mm> = Length::new(10.0);length /= 2.0;let expected: Length<f32, Mm> = Length::new(5.0);assert_eq!(length, expected);}#[test]fn test_negation() {let length: Length<f32, Cm> = Length::new(5.0);let result = -length;let expected: Length<f32, Cm> = Length::new(-5.0);assert_eq!(result, expected);}#[test]fn test_cast() {let length_as_i32: Length<i32, Cm> = Length::new(5);let result: Length<f32, Cm> = length_as_i32.cast();let length_as_f32: Length<f32, Cm> = Length::new(5.0);assert_eq!(result, length_as_f32);}#[test]fn test_equality() {let length_5_point_0: Length<f32, Cm> = Length::new(5.0);let length_5_point_1: Length<f32, Cm> = Length::new(5.1);let length_0_point_1: Length<f32, Cm> = Length::new(0.1);assert!(length_5_point_0 == length_5_point_1 - length_0_point_1);assert!(length_5_point_0 != length_5_point_1);}#[test]fn test_order() {let length_5_point_0: Length<f32, Cm> = Length::new(5.0);let length_5_point_1: Length<f32, Cm> = Length::new(5.1);let length_0_point_1: Length<f32, Cm> = Length::new(0.1);assert!(length_5_point_0 < length_5_point_1);assert!(length_5_point_0 <= length_5_point_1);assert!(length_5_point_0 <= length_5_point_1 - length_0_point_1);assert!(length_5_point_1 > length_5_point_0);assert!(length_5_point_1 >= length_5_point_0);assert!(length_5_point_0 >= length_5_point_1 - length_0_point_1);}#[test]fn test_zero_add() {type LengthCm = Length<f32, Cm>;let length: LengthCm = Length::new(5.0);let result = length - LengthCm::zero();assert_eq!(result, length);}#[test]fn test_zero_division() {type LengthCm = Length<f32, Cm>;let length: LengthCm = Length::new(5.0);let length_zero: LengthCm = Length::zero();let result = length / length_zero;let expected: Scale<f32, Cm, Cm> = Scale::new(INFINITY);assert_eq!(result, expected);}
}

二、结构体定义

#[repr(C)]
pub struct Length<T, Unit>(pub T, #[doc(hidden)] pub PhantomData<Unit>);
  • #[repr©]：保证结构体在内存中的布局与C语言兼容，通常用于确保与C/C++代码或外部接口的二进制兼容性。
  • PhantomData：一个零大小的类型，用于在编译时携带类型信息，而不会增加结构体的大小。这里用于确保单位的一致性。

三、实现Clone

impl<T: Clone, U> Clone for Length<T, U> {fn clone(&self) -> Self {Length(self.0.clone(), PhantomData)}
}
  • 这段代码实现了Clone trait，允许Length类型的值被克隆。
  • PhantomData的实例化应使用PhantomData::，而不是直接使用PhantomData（虽然Rust编译器通常可以推断）。

四、cast和try_cast方法

impl<T: NumCast + Clone, U> Length<T, U> {/// Cast from one numeric representation to another, preserving the units.#[inline]pub fn cast<NewT: NumCast>(self) -> Length<NewT, U> {self.try_cast().unwrap()}/// Fallible cast from one numeric representation to another, preserving the units.pub fn try_cast<NewT: NumCast>(self) -> Option<Length<NewT, U>> {NumCast::from(self.0).map(Length::new)}
}
  • 这里我们使用了num_traits::NumCast trait来实现数值类型之间的转换。
  • cast方法调用try_cast并解包Option，这意味着如果转换失败，程序将会panic。
  • try_cast方法尝试将Length的数值部分从类型T转换为NewT，如果成功，则使用新的数值和原始的单位类型U创建一个新的Length值。

五、其他trait实现

  • fmt::Debug：为Length实现Debug trait，使得Length值可以格式化输出。
  • Default：为Length实现Default trait，允许使用default()方法创建默认值的Length实例。
  • Hash：为Length实现Hash trait，使得Length值可以被哈希。
  • Length + Length 的加法
  • Length + &Length 的加法
  • Length 迭代器的求和（Sum）实现（针对可复制的情况）
  • &Length 迭代器的求和（Sum）实现
  • Length += Length 的加法
  • 减法实现
  • 比较特性（PartialEq, PartialOrd, Eq, Ord）的实现
  • 零值特性（Zero）的实现
  • 近似相等特性（ApproxEq）的实现
    #六、结束语
    这个结构体不仅提供了数值和单位的泛型表示，还通过实现各种 trait 来支持丰富的操作，如加减、克隆、比较和哈希等。这使得 Length<T, U> 能够与 Rust 标准库中的许多算法和数据结构无缝协作，同时保持了泛型性和类型安全。
http://www.tj-hxxt.cn/news/98255.html

相关文章：

  • 国内伪娘做网站免费加客源软件
  • 做告状网站手机建站系统
  • 免费公司网站怎么做湖北网络营销网站
  • 湖南网站建设方案优化如何在百度发布信息推广
  • 做网站要什么条件广东网站se0优化公司
  • 手机网站制作移动高端网站建设简述影响关键词优化的因素
  • 西安网站建设企业网络营销的营销理念
  • 网站盒子怎么做新闻摘抄2022最新5篇
  • 网站建设销售话术网页设计论文
  • 青海海东住房和城乡建设局网站吉林seo管理平台
  • 59网站一起做网店女鞋百度手机端排名
  • 哪里设计网页便宜天津的网络优化公司排名
  • 做影视网站不备案免费推广平台哪些比较好
  • 线上电商平台企业站seo
  • 深圳营销网站软文网站发布平台
  • 网站添加在线客服免费正规的接单平台
  • 小白怎么建设网站指数分布的期望和方差
  • 濮阳网站建设陈帅东莞seo建站咨询
  • 做网站 就镇江网页设计
  • 钙网logo免费使用seo排名规则
  • java做网站pdf软文营销经典案例
  • 杭州网站设计公司百度新闻排行榜
  • 广州网站公司制作网站广告联盟代理平台
  • 营销号是啥意思seo排名优化点击软件有哪些
  • 网站遭受攻击企业邮箱哪个好
  • 网站开发课程学习报告公司网站的推广
  • flash里鼠标可以跟随到网站上就不能跟随了石家庄seo优化
  • 怎么接网站来做网络营销策略的演变
  • wordpress国外模板搜索引擎营销优化
  • 整站优化网站报价指数工具