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460 lines
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<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/home/newkirk/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/itoa-1.0.17/src/lib.rs`."><title>lib.rs - source</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Italic-81dc35de.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-MediumItalic-ccf7e434.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2"href="../../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../../static.files/rustdoc-ca0dd0c4.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="itoa" data-themes="" data-resource-suffix="" data-rustdoc-version="1.93.1 (01f6ddf75 2026-02-11) (Arch Linux rust 1:1.93.1-1)" data-channel="1.93.1" data-search-js="search-9e2438ea.js" data-stringdex-js="stringdex-a3946164.js" data-settings-js="settings-c38705f0.js" ><script src="../../static.files/storage-e2aeef58.js"></script><script defer src="../../static.files/src-script-813739b1.js"></script><script defer src="../../src-files.js"></script><script defer src="../../static.files/main-a410ff4d.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-263c88ec.css"></noscript><link rel="alternate icon" type="image/png" href="../../static.files/favicon-32x32-eab170b8.png"><link rel="icon" type="image/svg+xml" href="../../static.files/favicon-044be391.svg"></head><body class="rustdoc src"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="src-sidebar-title"><h2>Files</h2></div></nav><div class="sidebar-resizer" title="Drag to resize sidebar"></div><main><section id="main-content" class="content"><div class="main-heading"><h1><div class="sub-heading">itoa/</div>lib.rs</h1><rustdoc-toolbar></rustdoc-toolbar></div><div class="example-wrap digits-3"><pre class="rust"><code><a href=#1 id=1 data-nosnippet>1</a><span class="doccomment">//! [![github]](https://github.com/dtolnay/itoa)&ensp;[![crates-io]](https://crates.io/crates/itoa)&ensp;[![docs-rs]](https://docs.rs/itoa)
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<a href=#2 id=2 data-nosnippet>2</a>//!
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<a href=#3 id=3 data-nosnippet>3</a>//! [github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github
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<a href=#4 id=4 data-nosnippet>4</a>//! [crates-io]: https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust
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<a href=#5 id=5 data-nosnippet>5</a>//! [docs-rs]: https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs
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<a href=#6 id=6 data-nosnippet>6</a>//!
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<a href=#7 id=7 data-nosnippet>7</a>//! <br>
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<a href=#8 id=8 data-nosnippet>8</a>//!
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<a href=#9 id=9 data-nosnippet>9</a>//! This crate provides a fast conversion of integer primitives to decimal
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<a href=#10 id=10 data-nosnippet>10</a>//! strings. The implementation comes straight from [libcore] but avoids the
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<a href=#11 id=11 data-nosnippet>11</a>//! performance penalty of going through [`core::fmt::Formatter`].
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<a href=#12 id=12 data-nosnippet>12</a>//!
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<a href=#13 id=13 data-nosnippet>13</a>//! See also [`zmij`] for printing floating point primitives.
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<a href=#14 id=14 data-nosnippet>14</a>//!
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<a href=#15 id=15 data-nosnippet>15</a>//! [libcore]: https://github.com/rust-lang/rust/blob/1.92.0/library/core/src/fmt/num.rs#L190-L253
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<a href=#16 id=16 data-nosnippet>16</a>//! [`zmij`]: https://github.com/dtolnay/zmij
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<a href=#17 id=17 data-nosnippet>17</a>//!
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<a href=#18 id=18 data-nosnippet>18</a>//! # Example
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<a href=#19 id=19 data-nosnippet>19</a>//!
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<a href=#20 id=20 data-nosnippet>20</a>//! ```
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<a href=#21 id=21 data-nosnippet>21</a>//! fn main() {
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<a href=#22 id=22 data-nosnippet>22</a>//! let mut buffer = itoa::Buffer::new();
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<a href=#23 id=23 data-nosnippet>23</a>//! let printed = buffer.format(128u64);
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<a href=#24 id=24 data-nosnippet>24</a>//! assert_eq!(printed, "128");
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<a href=#25 id=25 data-nosnippet>25</a>//! }
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<a href=#26 id=26 data-nosnippet>26</a>//! ```
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<a href=#27 id=27 data-nosnippet>27</a>//!
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<a href=#28 id=28 data-nosnippet>28</a>//! # Performance
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<a href=#29 id=29 data-nosnippet>29</a>//!
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<a href=#30 id=30 data-nosnippet>30</a>//! The [itoa-benchmark] compares this library and other Rust integer formatting
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<a href=#31 id=31 data-nosnippet>31</a>//! implementations across a range of integer sizes. The vertical axis in this
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<a href=#32 id=32 data-nosnippet>32</a>//! chart shows nanoseconds taken by a single execution of
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<a href=#33 id=33 data-nosnippet>33</a>//! `itoa::Buffer::new().format(value)` so a lower result indicates a faster
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<a href=#34 id=34 data-nosnippet>34</a>//! library.
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<a href=#35 id=35 data-nosnippet>35</a>//!
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<a href=#36 id=36 data-nosnippet>36</a>//! [itoa-benchmark]: https://github.com/dtolnay/itoa-benchmark
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<a href=#37 id=37 data-nosnippet>37</a>//!
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<a href=#38 id=38 data-nosnippet>38</a>//! 
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<a href=#39 id=39 data-nosnippet>39</a>
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<a href=#40 id=40 data-nosnippet>40</a></span><span class="attr">#![doc(html_root_url = <span class="string">"https://docs.rs/itoa/1.0.17"</span>)]
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<a href=#41 id=41 data-nosnippet>41</a>#![no_std]
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<a href=#42 id=42 data-nosnippet>42</a>#![allow(
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<a href=#43 id=43 data-nosnippet>43</a> clippy::cast_lossless,
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<a href=#44 id=44 data-nosnippet>44</a> clippy::cast_possible_truncation,
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<a href=#45 id=45 data-nosnippet>45</a> clippy::cast_sign_loss,
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<a href=#46 id=46 data-nosnippet>46</a> clippy::expl_impl_clone_on_copy,
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<a href=#47 id=47 data-nosnippet>47</a> clippy::identity_op,
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<a href=#48 id=48 data-nosnippet>48</a> clippy::items_after_statements,
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<a href=#49 id=49 data-nosnippet>49</a> clippy::must_use_candidate,
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<a href=#50 id=50 data-nosnippet>50</a> clippy::needless_doctest_main,
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<a href=#51 id=51 data-nosnippet>51</a> clippy::unreadable_literal
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<a href=#52 id=52 data-nosnippet>52</a>)]
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<a href=#53 id=53 data-nosnippet>53</a>
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<a href=#54 id=54 data-nosnippet>54</a></span><span class="kw">mod </span>u128_ext;
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<a href=#55 id=55 data-nosnippet>55</a>
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<a href=#56 id=56 data-nosnippet>56</a><span class="kw">use </span>core::hint;
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<a href=#57 id=57 data-nosnippet>57</a><span class="kw">use </span>core::mem::{<span class="self">self</span>, MaybeUninit};
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<a href=#58 id=58 data-nosnippet>58</a><span class="kw">use </span>core::ptr;
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<a href=#59 id=59 data-nosnippet>59</a><span class="kw">use </span>core::str;
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<a href=#60 id=60 data-nosnippet>60</a><span class="attr">#[cfg(feature = <span class="string">"no-panic"</span>)]
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<a href=#61 id=61 data-nosnippet>61</a></span><span class="kw">use </span>no_panic::no_panic;
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<a href=#62 id=62 data-nosnippet>62</a>
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<a href=#63 id=63 data-nosnippet>63</a><span class="doccomment">/// A correctly sized stack allocation for the formatted integer to be written
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<a href=#64 id=64 data-nosnippet>64</a>/// into.
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<a href=#65 id=65 data-nosnippet>65</a>///
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<a href=#66 id=66 data-nosnippet>66</a>/// # Example
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<a href=#67 id=67 data-nosnippet>67</a>///
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<a href=#68 id=68 data-nosnippet>68</a>/// ```
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<a href=#69 id=69 data-nosnippet>69</a>/// let mut buffer = itoa::Buffer::new();
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<a href=#70 id=70 data-nosnippet>70</a>/// let printed = buffer.format(1234);
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<a href=#71 id=71 data-nosnippet>71</a>/// assert_eq!(printed, "1234");
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<a href=#72 id=72 data-nosnippet>72</a>/// ```
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<a href=#73 id=73 data-nosnippet>73</a></span><span class="kw">pub struct </span>Buffer {
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<a href=#74 id=74 data-nosnippet>74</a> bytes: [MaybeUninit<u8>; i128::MAX_STR_LEN],
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<a href=#75 id=75 data-nosnippet>75</a>}
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<a href=#76 id=76 data-nosnippet>76</a>
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<a href=#77 id=77 data-nosnippet>77</a><span class="kw">impl </span>Default <span class="kw">for </span>Buffer {
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<a href=#78 id=78 data-nosnippet>78</a> <span class="attr">#[inline]
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<a href=#79 id=79 data-nosnippet>79</a> </span><span class="kw">fn </span>default() -> Buffer {
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<a href=#80 id=80 data-nosnippet>80</a> Buffer::new()
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<a href=#81 id=81 data-nosnippet>81</a> }
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<a href=#82 id=82 data-nosnippet>82</a>}
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<a href=#83 id=83 data-nosnippet>83</a>
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<a href=#84 id=84 data-nosnippet>84</a><span class="kw">impl </span>Copy <span class="kw">for </span>Buffer {}
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<a href=#85 id=85 data-nosnippet>85</a>
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<a href=#86 id=86 data-nosnippet>86</a><span class="attr">#[allow(clippy::non_canonical_clone_impl)]
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<a href=#87 id=87 data-nosnippet>87</a></span><span class="kw">impl </span>Clone <span class="kw">for </span>Buffer {
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<a href=#88 id=88 data-nosnippet>88</a> <span class="attr">#[inline]
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<a href=#89 id=89 data-nosnippet>89</a> </span><span class="kw">fn </span>clone(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="self">Self </span>{
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<a href=#90 id=90 data-nosnippet>90</a> Buffer::new()
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<a href=#91 id=91 data-nosnippet>91</a> }
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<a href=#92 id=92 data-nosnippet>92</a>}
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<a href=#93 id=93 data-nosnippet>93</a>
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<a href=#94 id=94 data-nosnippet>94</a><span class="kw">impl </span>Buffer {
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<a href=#95 id=95 data-nosnippet>95</a> <span class="doccomment">/// This is a cheap operation; you don't need to worry about reusing buffers
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<a href=#96 id=96 data-nosnippet>96</a> /// for efficiency.
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<a href=#97 id=97 data-nosnippet>97</a> </span><span class="attr">#[inline]
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<a href=#98 id=98 data-nosnippet>98</a> #[cfg_attr(feature = <span class="string">"no-panic"</span>, no_panic)]
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<a href=#99 id=99 data-nosnippet>99</a> </span><span class="kw">pub fn </span>new() -> Buffer {
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<a href=#100 id=100 data-nosnippet>100</a> <span class="kw">let </span>bytes = [MaybeUninit::<u8>::uninit(); i128::MAX_STR_LEN];
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<a href=#101 id=101 data-nosnippet>101</a> Buffer { bytes }
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<a href=#102 id=102 data-nosnippet>102</a> }
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<a href=#103 id=103 data-nosnippet>103</a>
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<a href=#104 id=104 data-nosnippet>104</a> <span class="doccomment">/// Print an integer into this buffer and return a reference to its string
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<a href=#105 id=105 data-nosnippet>105</a> /// representation within the buffer.
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<a href=#106 id=106 data-nosnippet>106</a> </span><span class="attr">#[cfg_attr(feature = <span class="string">"no-panic"</span>, no_panic)]
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<a href=#107 id=107 data-nosnippet>107</a> </span><span class="kw">pub fn </span>format<I: Integer>(<span class="kw-2">&mut </span><span class="self">self</span>, i: I) -> <span class="kw-2">&</span>str {
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<a href=#108 id=108 data-nosnippet>108</a> <span class="kw">let </span>string = i.write(<span class="kw">unsafe </span>{
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<a href=#109 id=109 data-nosnippet>109</a> <span class="kw-2">&mut *</span><span class="macro">ptr::addr_of_mut!</span>(<span class="self">self</span>.bytes).cast::<<I <span class="kw">as </span>private::Sealed>::Buffer>()
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<a href=#110 id=110 data-nosnippet>110</a> });
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<a href=#111 id=111 data-nosnippet>111</a> <span class="kw">if </span>string.len() > I::MAX_STR_LEN {
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<a href=#112 id=112 data-nosnippet>112</a> <span class="kw">unsafe </span>{ hint::unreachable_unchecked() };
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<a href=#113 id=113 data-nosnippet>113</a> }
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<a href=#114 id=114 data-nosnippet>114</a> string
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<a href=#115 id=115 data-nosnippet>115</a> }
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<a href=#116 id=116 data-nosnippet>116</a>}
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<a href=#117 id=117 data-nosnippet>117</a>
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<a href=#118 id=118 data-nosnippet>118</a><span class="doccomment">/// An integer that can be written into an [`itoa::Buffer`][Buffer].
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<a href=#119 id=119 data-nosnippet>119</a>///
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<a href=#120 id=120 data-nosnippet>120</a>/// This trait is sealed and cannot be implemented for types outside of itoa.
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<a href=#121 id=121 data-nosnippet>121</a></span><span class="kw">pub trait </span>Integer: private::Sealed {
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<a href=#122 id=122 data-nosnippet>122</a> <span class="doccomment">/// The maximum length of string that formatting an integer of this type can
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<a href=#123 id=123 data-nosnippet>123</a> /// produce on the current target platform.
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<a href=#124 id=124 data-nosnippet>124</a> </span><span class="kw">const </span>MAX_STR_LEN: usize;
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<a href=#125 id=125 data-nosnippet>125</a>}
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<a href=#126 id=126 data-nosnippet>126</a>
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<a href=#127 id=127 data-nosnippet>127</a><span class="comment">// Seal to prevent downstream implementations of the Integer trait.
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<a href=#128 id=128 data-nosnippet>128</a></span><span class="kw">mod </span>private {
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<a href=#129 id=129 data-nosnippet>129</a> <span class="attr">#[doc(hidden)]
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<a href=#130 id=130 data-nosnippet>130</a> </span><span class="kw">pub trait </span>Sealed: Copy {
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<a href=#131 id=131 data-nosnippet>131</a> <span class="attr">#[doc(hidden)]
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<a href=#132 id=132 data-nosnippet>132</a> </span><span class="kw">type </span>Buffer: <span class="lifetime">'static</span>;
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<a href=#133 id=133 data-nosnippet>133</a> <span class="kw">fn </span>write(<span class="self">self</span>, buf: <span class="kw-2">&mut </span><span class="self">Self</span>::Buffer) -> <span class="kw-2">&</span>str;
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<a href=#134 id=134 data-nosnippet>134</a> }
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<a href=#135 id=135 data-nosnippet>135</a>}
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<a href=#136 id=136 data-nosnippet>136</a>
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<a href=#137 id=137 data-nosnippet>137</a><span class="macro">macro_rules!</span> impl_Integer {
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<a href=#138 id=138 data-nosnippet>138</a> (<span class="macro-nonterminal">$Signed</span>:ident, <span class="macro-nonterminal">$Unsigned</span>:ident) => {
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<a href=#139 id=139 data-nosnippet>139</a> <span class="kw">const _</span>: () = {
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<a href=#140 id=140 data-nosnippet>140</a> <span class="macro">assert!</span>(<span class="macro-nonterminal">$Signed::MIN </span>< <span class="number">0</span>, <span class="string">"need signed"</span>);
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<a href=#141 id=141 data-nosnippet>141</a> <span class="macro">assert!</span>(<span class="macro-nonterminal">$Unsigned::MIN </span>== <span class="number">0</span>, <span class="string">"need unsigned"</span>);
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<a href=#142 id=142 data-nosnippet>142</a> <span class="macro">assert!</span>(<span class="macro-nonterminal">$Signed::BITS </span>== <span class="macro-nonterminal">$Unsigned::BITS</span>, <span class="string">"need counterparts"</span>);
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<a href=#143 id=143 data-nosnippet>143</a> };
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<a href=#144 id=144 data-nosnippet>144</a>
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<a href=#145 id=145 data-nosnippet>145</a> <span class="kw">impl </span>Integer <span class="kw">for </span><span class="macro-nonterminal">$Unsigned </span>{
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<a href=#146 id=146 data-nosnippet>146</a> <span class="kw">const </span>MAX_STR_LEN: usize = <span class="macro-nonterminal">$Unsigned::MAX</span>.ilog10() <span class="kw">as </span>usize + <span class="number">1</span>;
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<a href=#147 id=147 data-nosnippet>147</a> }
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<a href=#148 id=148 data-nosnippet>148</a>
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<a href=#149 id=149 data-nosnippet>149</a> <span class="kw">impl </span>private::Sealed <span class="kw">for </span><span class="macro-nonterminal">$Unsigned </span>{
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<a href=#150 id=150 data-nosnippet>150</a> <span class="kw">type </span>Buffer = [MaybeUninit<u8>; <span class="self">Self</span>::MAX_STR_LEN];
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<a href=#151 id=151 data-nosnippet>151</a>
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<a href=#152 id=152 data-nosnippet>152</a> <span class="attr">#[inline]
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<a href=#153 id=153 data-nosnippet>153</a> #[cfg_attr(feature = <span class="string">"no-panic"</span>, no_panic)]
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<a href=#154 id=154 data-nosnippet>154</a> </span><span class="kw">fn </span>write(<span class="self">self</span>, buf: <span class="kw-2">&mut </span><span class="self">Self</span>::Buffer) -> <span class="kw-2">&</span>str {
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<a href=#155 id=155 data-nosnippet>155</a> <span class="kw">let </span>offset = Unsigned::fmt(<span class="self">self</span>, buf);
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<a href=#156 id=156 data-nosnippet>156</a> <span class="comment">// SAFETY: Starting from `offset`, all elements of the slice have been set.
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<a href=#157 id=157 data-nosnippet>157</a> </span><span class="kw">unsafe </span>{ slice_buffer_to_str(buf, offset) }
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<a href=#158 id=158 data-nosnippet>158</a> }
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<a href=#159 id=159 data-nosnippet>159</a> }
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<a href=#160 id=160 data-nosnippet>160</a>
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<a href=#161 id=161 data-nosnippet>161</a> <span class="kw">impl </span>Integer <span class="kw">for </span><span class="macro-nonterminal">$Signed </span>{
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<a href=#162 id=162 data-nosnippet>162</a> <span class="kw">const </span>MAX_STR_LEN: usize = <span class="macro-nonterminal">$Signed::MAX</span>.ilog10() <span class="kw">as </span>usize + <span class="number">2</span>;
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<a href=#163 id=163 data-nosnippet>163</a> }
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<a href=#164 id=164 data-nosnippet>164</a>
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<a href=#165 id=165 data-nosnippet>165</a> <span class="kw">impl </span>private::Sealed <span class="kw">for </span><span class="macro-nonterminal">$Signed </span>{
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<a href=#166 id=166 data-nosnippet>166</a> <span class="kw">type </span>Buffer = [MaybeUninit<u8>; <span class="self">Self</span>::MAX_STR_LEN];
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<a href=#167 id=167 data-nosnippet>167</a>
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<a href=#168 id=168 data-nosnippet>168</a> <span class="attr">#[inline]
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<a href=#169 id=169 data-nosnippet>169</a> #[cfg_attr(feature = <span class="string">"no-panic"</span>, no_panic)]
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<a href=#170 id=170 data-nosnippet>170</a> </span><span class="kw">fn </span>write(<span class="self">self</span>, buf: <span class="kw-2">&mut </span><span class="self">Self</span>::Buffer) -> <span class="kw-2">&</span>str {
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<a href=#171 id=171 data-nosnippet>171</a> <span class="kw">let </span><span class="kw-2">mut </span>offset = <span class="self">Self</span>::MAX_STR_LEN - <span class="macro-nonterminal">$Unsigned::MAX_STR_LEN</span>;
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<a href=#172 id=172 data-nosnippet>172</a> offset += Unsigned::fmt(
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<a href=#173 id=173 data-nosnippet>173</a> <span class="self">self</span>.unsigned_abs(),
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<a href=#174 id=174 data-nosnippet>174</a> (<span class="kw-2">&mut </span>buf[offset..]).try_into().unwrap(),
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<a href=#175 id=175 data-nosnippet>175</a> );
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<a href=#176 id=176 data-nosnippet>176</a> <span class="kw">if </span><span class="self">self </span>< <span class="number">0 </span>{
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<a href=#177 id=177 data-nosnippet>177</a> offset -= <span class="number">1</span>;
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<a href=#178 id=178 data-nosnippet>178</a> buf[offset].write(<span class="string">b'-'</span>);
|
||
<a href=#179 id=179 data-nosnippet>179</a> }
|
||
<a href=#180 id=180 data-nosnippet>180</a> <span class="comment">// SAFETY: Starting from `offset`, all elements of the slice have been set.
|
||
<a href=#181 id=181 data-nosnippet>181</a> </span><span class="kw">unsafe </span>{ slice_buffer_to_str(buf, offset) }
|
||
<a href=#182 id=182 data-nosnippet>182</a> }
|
||
<a href=#183 id=183 data-nosnippet>183</a> }
|
||
<a href=#184 id=184 data-nosnippet>184</a> };
|
||
<a href=#185 id=185 data-nosnippet>185</a>}
|
||
<a href=#186 id=186 data-nosnippet>186</a>
|
||
<a href=#187 id=187 data-nosnippet>187</a><span class="macro">impl_Integer!</span>(i8, u8);
|
||
<a href=#188 id=188 data-nosnippet>188</a><span class="macro">impl_Integer!</span>(i16, u16);
|
||
<a href=#189 id=189 data-nosnippet>189</a><span class="macro">impl_Integer!</span>(i32, u32);
|
||
<a href=#190 id=190 data-nosnippet>190</a><span class="macro">impl_Integer!</span>(i64, u64);
|
||
<a href=#191 id=191 data-nosnippet>191</a><span class="macro">impl_Integer!</span>(i128, u128);
|
||
<a href=#192 id=192 data-nosnippet>192</a>
|
||
<a href=#193 id=193 data-nosnippet>193</a><span class="macro">macro_rules!</span> impl_Integer_size {
|
||
<a href=#194 id=194 data-nosnippet>194</a> (<span class="macro-nonterminal">$t</span>:ty <span class="kw">as </span><span class="macro-nonterminal">$primitive</span>:ident <span class="attr">#[cfg(target_pointer_width = <span class="macro-nonterminal">$width</span>:literal)]</span>) => {
|
||
<a href=#195 id=195 data-nosnippet>195</a> <span class="attr">#[cfg(target_pointer_width = <span class="macro-nonterminal">$width</span>)]
|
||
<a href=#196 id=196 data-nosnippet>196</a> </span><span class="kw">impl </span>Integer <span class="kw">for </span><span class="macro-nonterminal">$t </span>{
|
||
<a href=#197 id=197 data-nosnippet>197</a> <span class="kw">const </span>MAX_STR_LEN: usize = <<span class="macro-nonterminal">$primitive </span><span class="kw">as </span>Integer>::MAX_STR_LEN;
|
||
<a href=#198 id=198 data-nosnippet>198</a> }
|
||
<a href=#199 id=199 data-nosnippet>199</a>
|
||
<a href=#200 id=200 data-nosnippet>200</a> <span class="attr">#[cfg(target_pointer_width = <span class="macro-nonterminal">$width</span>)]
|
||
<a href=#201 id=201 data-nosnippet>201</a> </span><span class="kw">impl </span>private::Sealed <span class="kw">for </span><span class="macro-nonterminal">$t </span>{
|
||
<a href=#202 id=202 data-nosnippet>202</a> <span class="kw">type </span>Buffer = <<span class="macro-nonterminal">$primitive </span><span class="kw">as </span>private::Sealed>::Buffer;
|
||
<a href=#203 id=203 data-nosnippet>203</a>
|
||
<a href=#204 id=204 data-nosnippet>204</a> <span class="attr">#[inline]
|
||
<a href=#205 id=205 data-nosnippet>205</a> #[cfg_attr(feature = <span class="string">"no-panic"</span>, no_panic)]
|
||
<a href=#206 id=206 data-nosnippet>206</a> </span><span class="kw">fn </span>write(<span class="self">self</span>, buf: <span class="kw-2">&mut </span><span class="self">Self</span>::Buffer) -> <span class="kw-2">&</span>str {
|
||
<a href=#207 id=207 data-nosnippet>207</a> (<span class="self">self </span><span class="kw">as </span><span class="macro-nonterminal">$primitive</span>).write(buf)
|
||
<a href=#208 id=208 data-nosnippet>208</a> }
|
||
<a href=#209 id=209 data-nosnippet>209</a> }
|
||
<a href=#210 id=210 data-nosnippet>210</a> };
|
||
<a href=#211 id=211 data-nosnippet>211</a>}
|
||
<a href=#212 id=212 data-nosnippet>212</a>
|
||
<a href=#213 id=213 data-nosnippet>213</a><span class="macro">impl_Integer_size!</span>(isize <span class="kw">as </span>i16 <span class="attr">#[cfg(target_pointer_width = <span class="string">"16"</span>)]</span>);
|
||
<a href=#214 id=214 data-nosnippet>214</a><span class="macro">impl_Integer_size!</span>(usize <span class="kw">as </span>u16 <span class="attr">#[cfg(target_pointer_width = <span class="string">"16"</span>)]</span>);
|
||
<a href=#215 id=215 data-nosnippet>215</a><span class="macro">impl_Integer_size!</span>(isize <span class="kw">as </span>i32 <span class="attr">#[cfg(target_pointer_width = <span class="string">"32"</span>)]</span>);
|
||
<a href=#216 id=216 data-nosnippet>216</a><span class="macro">impl_Integer_size!</span>(usize <span class="kw">as </span>u32 <span class="attr">#[cfg(target_pointer_width = <span class="string">"32"</span>)]</span>);
|
||
<a href=#217 id=217 data-nosnippet>217</a><span class="macro">impl_Integer_size!</span>(isize <span class="kw">as </span>i64 <span class="attr">#[cfg(target_pointer_width = <span class="string">"64"</span>)]</span>);
|
||
<a href=#218 id=218 data-nosnippet>218</a><span class="macro">impl_Integer_size!</span>(usize <span class="kw">as </span>u64 <span class="attr">#[cfg(target_pointer_width = <span class="string">"64"</span>)]</span>);
|
||
<a href=#219 id=219 data-nosnippet>219</a>
|
||
<a href=#220 id=220 data-nosnippet>220</a><span class="attr">#[repr(C, align(<span class="number">2</span>))]
|
||
<a href=#221 id=221 data-nosnippet>221</a></span><span class="kw">struct </span>DecimalPairs([u8; <span class="number">200</span>]);
|
||
<a href=#222 id=222 data-nosnippet>222</a>
|
||
<a href=#223 id=223 data-nosnippet>223</a><span class="comment">// The string of all two-digit numbers in range 00..99 is used as a lookup table.
|
||
<a href=#224 id=224 data-nosnippet>224</a></span><span class="kw">static </span>DECIMAL_PAIRS: DecimalPairs = DecimalPairs(
|
||
<a href=#225 id=225 data-nosnippet>225</a> <span class="kw-2">*</span><span class="string">b"0001020304050607080910111213141516171819\
|
||
<a href=#226 id=226 data-nosnippet>226</a> 2021222324252627282930313233343536373839\
|
||
<a href=#227 id=227 data-nosnippet>227</a> 4041424344454647484950515253545556575859\
|
||
<a href=#228 id=228 data-nosnippet>228</a> 6061626364656667686970717273747576777879\
|
||
<a href=#229 id=229 data-nosnippet>229</a> 8081828384858687888990919293949596979899"</span>,
|
||
<a href=#230 id=230 data-nosnippet>230</a>);
|
||
<a href=#231 id=231 data-nosnippet>231</a>
|
||
<a href=#232 id=232 data-nosnippet>232</a><span class="comment">// Returns {value / 100, value % 100} correct for values of up to 4 digits.
|
||
<a href=#233 id=233 data-nosnippet>233</a></span><span class="kw">fn </span>divmod100(value: u32) -> (u32, u32) {
|
||
<a href=#234 id=234 data-nosnippet>234</a> <span class="macro">debug_assert!</span>(value < <span class="number">10_000</span>);
|
||
<a href=#235 id=235 data-nosnippet>235</a> <span class="kw">const </span>EXP: u32 = <span class="number">19</span>; <span class="comment">// 19 is faster or equal to 12 even for 3 digits.
|
||
<a href=#236 id=236 data-nosnippet>236</a> </span><span class="kw">const </span>SIG: u32 = (<span class="number">1 </span><< EXP) / <span class="number">100 </span>+ <span class="number">1</span>;
|
||
<a href=#237 id=237 data-nosnippet>237</a> <span class="kw">let </span>div = (value * SIG) >> EXP; <span class="comment">// value / 100
|
||
<a href=#238 id=238 data-nosnippet>238</a> </span>(div, value - div * <span class="number">100</span>)
|
||
<a href=#239 id=239 data-nosnippet>239</a>}
|
||
<a href=#240 id=240 data-nosnippet>240</a>
|
||
<a href=#241 id=241 data-nosnippet>241</a><span class="doccomment">/// This function converts a slice of ascii characters into a `&str` starting
|
||
<a href=#242 id=242 data-nosnippet>242</a>/// from `offset`.
|
||
<a href=#243 id=243 data-nosnippet>243</a>///
|
||
<a href=#244 id=244 data-nosnippet>244</a>/// # Safety
|
||
<a href=#245 id=245 data-nosnippet>245</a>///
|
||
<a href=#246 id=246 data-nosnippet>246</a>/// `buf` content starting from `offset` index MUST BE initialized and MUST BE
|
||
<a href=#247 id=247 data-nosnippet>247</a>/// ascii characters.
|
||
<a href=#248 id=248 data-nosnippet>248</a></span><span class="attr">#[cfg_attr(feature = <span class="string">"no-panic"</span>, no_panic)]
|
||
<a href=#249 id=249 data-nosnippet>249</a></span><span class="kw">unsafe fn </span>slice_buffer_to_str(buf: <span class="kw-2">&</span>[MaybeUninit<u8>], offset: usize) -> <span class="kw-2">&</span>str {
|
||
<a href=#250 id=250 data-nosnippet>250</a> <span class="comment">// SAFETY: `offset` is always included between 0 and `buf`'s length.
|
||
<a href=#251 id=251 data-nosnippet>251</a> </span><span class="kw">let </span>written = <span class="kw">unsafe </span>{ buf.get_unchecked(offset..) };
|
||
<a href=#252 id=252 data-nosnippet>252</a> <span class="comment">// SAFETY: (`assume_init_ref`) All buf content since offset is set.
|
||
<a href=#253 id=253 data-nosnippet>253</a> // SAFETY: (`from_utf8_unchecked`) Writes use ASCII from the lookup table exclusively.
|
||
<a href=#254 id=254 data-nosnippet>254</a> </span><span class="kw">unsafe </span>{ str::from_utf8_unchecked(<span class="kw-2">&*</span>(written <span class="kw">as </span><span class="kw-2">*const </span>[MaybeUninit<u8>] <span class="kw">as </span><span class="kw-2">*const </span>[u8])) }
|
||
<a href=#255 id=255 data-nosnippet>255</a>}
|
||
<a href=#256 id=256 data-nosnippet>256</a>
|
||
<a href=#257 id=257 data-nosnippet>257</a><span class="kw">trait </span>Unsigned: Integer {
|
||
<a href=#258 id=258 data-nosnippet>258</a> <span class="kw">fn </span>fmt(<span class="self">self</span>, buf: <span class="kw-2">&mut </span><span class="self">Self</span>::Buffer) -> usize;
|
||
<a href=#259 id=259 data-nosnippet>259</a>}
|
||
<a href=#260 id=260 data-nosnippet>260</a>
|
||
<a href=#261 id=261 data-nosnippet>261</a><span class="macro">macro_rules!</span> impl_Unsigned {
|
||
<a href=#262 id=262 data-nosnippet>262</a> (<span class="macro-nonterminal">$Unsigned</span>:ident) => {
|
||
<a href=#263 id=263 data-nosnippet>263</a> <span class="kw">impl </span>Unsigned <span class="kw">for </span><span class="macro-nonterminal">$Unsigned </span>{
|
||
<a href=#264 id=264 data-nosnippet>264</a> <span class="attr">#[cfg_attr(feature = <span class="string">"no-panic"</span>, no_panic)]
|
||
<a href=#265 id=265 data-nosnippet>265</a> </span><span class="kw">fn </span>fmt(<span class="self">self</span>, buf: <span class="kw-2">&mut </span><span class="self">Self</span>::Buffer) -> usize {
|
||
<a href=#266 id=266 data-nosnippet>266</a> <span class="comment">// Count the number of bytes in buf that are not initialized.
|
||
<a href=#267 id=267 data-nosnippet>267</a> </span><span class="kw">let </span><span class="kw-2">mut </span>offset = buf.len();
|
||
<a href=#268 id=268 data-nosnippet>268</a> <span class="comment">// Consume the least-significant decimals from a working copy.
|
||
<a href=#269 id=269 data-nosnippet>269</a> </span><span class="kw">let </span><span class="kw-2">mut </span>remain = <span class="self">self</span>;
|
||
<a href=#270 id=270 data-nosnippet>270</a>
|
||
<a href=#271 id=271 data-nosnippet>271</a> <span class="comment">// Format per four digits from the lookup table.
|
||
<a href=#272 id=272 data-nosnippet>272</a> // Four digits need a 16-bit $Unsigned or wider.
|
||
<a href=#273 id=273 data-nosnippet>273</a> </span><span class="kw">while </span>mem::size_of::<<span class="self">Self</span>>() > <span class="number">1
|
||
<a href=#274 id=274 data-nosnippet>274</a> </span>&& remain
|
||
<a href=#275 id=275 data-nosnippet>275</a> > <span class="number">999
|
||
<a href=#276 id=276 data-nosnippet>276</a> </span>.try_into()
|
||
<a href=#277 id=277 data-nosnippet>277</a> .expect(<span class="string">"branch is not hit for types that cannot fit 999 (u8)"</span>)
|
||
<a href=#278 id=278 data-nosnippet>278</a> {
|
||
<a href=#279 id=279 data-nosnippet>279</a> offset -= <span class="number">4</span>;
|
||
<a href=#280 id=280 data-nosnippet>280</a>
|
||
<a href=#281 id=281 data-nosnippet>281</a> <span class="comment">// pull two pairs
|
||
<a href=#282 id=282 data-nosnippet>282</a> </span><span class="kw">let </span>scale: <span class="self">Self </span>= <span class="number">1_00_00
|
||
<a href=#283 id=283 data-nosnippet>283</a> </span>.try_into()
|
||
<a href=#284 id=284 data-nosnippet>284</a> .expect(<span class="string">"branch is not hit for types that cannot fit 1E4 (u8)"</span>);
|
||
<a href=#285 id=285 data-nosnippet>285</a> <span class="kw">let </span>quad = remain % scale;
|
||
<a href=#286 id=286 data-nosnippet>286</a> remain /= scale;
|
||
<a href=#287 id=287 data-nosnippet>287</a> <span class="kw">let </span>(pair1, pair2) = divmod100(quad <span class="kw">as </span>u32);
|
||
<a href=#288 id=288 data-nosnippet>288</a> <span class="kw">unsafe </span>{
|
||
<a href=#289 id=289 data-nosnippet>289</a> buf[offset + <span class="number">0</span>]
|
||
<a href=#290 id=290 data-nosnippet>290</a> .write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair1 <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">0</span>));
|
||
<a href=#291 id=291 data-nosnippet>291</a> buf[offset + <span class="number">1</span>]
|
||
<a href=#292 id=292 data-nosnippet>292</a> .write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair1 <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">1</span>));
|
||
<a href=#293 id=293 data-nosnippet>293</a> buf[offset + <span class="number">2</span>]
|
||
<a href=#294 id=294 data-nosnippet>294</a> .write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair2 <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">0</span>));
|
||
<a href=#295 id=295 data-nosnippet>295</a> buf[offset + <span class="number">3</span>]
|
||
<a href=#296 id=296 data-nosnippet>296</a> .write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair2 <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">1</span>));
|
||
<a href=#297 id=297 data-nosnippet>297</a> }
|
||
<a href=#298 id=298 data-nosnippet>298</a> }
|
||
<a href=#299 id=299 data-nosnippet>299</a>
|
||
<a href=#300 id=300 data-nosnippet>300</a> <span class="comment">// Format per two digits from the lookup table.
|
||
<a href=#301 id=301 data-nosnippet>301</a> </span><span class="kw">if </span>remain > <span class="number">9 </span>{
|
||
<a href=#302 id=302 data-nosnippet>302</a> offset -= <span class="number">2</span>;
|
||
<a href=#303 id=303 data-nosnippet>303</a>
|
||
<a href=#304 id=304 data-nosnippet>304</a> <span class="kw">let </span>(last, pair) = divmod100(remain <span class="kw">as </span>u32);
|
||
<a href=#305 id=305 data-nosnippet>305</a> remain = last <span class="kw">as </span><span class="self">Self</span>;
|
||
<a href=#306 id=306 data-nosnippet>306</a> <span class="kw">unsafe </span>{
|
||
<a href=#307 id=307 data-nosnippet>307</a> buf[offset + <span class="number">0</span>]
|
||
<a href=#308 id=308 data-nosnippet>308</a> .write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">0</span>));
|
||
<a href=#309 id=309 data-nosnippet>309</a> buf[offset + <span class="number">1</span>]
|
||
<a href=#310 id=310 data-nosnippet>310</a> .write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">1</span>));
|
||
<a href=#311 id=311 data-nosnippet>311</a> }
|
||
<a href=#312 id=312 data-nosnippet>312</a> }
|
||
<a href=#313 id=313 data-nosnippet>313</a>
|
||
<a href=#314 id=314 data-nosnippet>314</a> <span class="comment">// Format the last remaining digit, if any.
|
||
<a href=#315 id=315 data-nosnippet>315</a> </span><span class="kw">if </span><span class="macro">remain !</span>= <span class="number">0 </span>|| <span class="self">self </span>== <span class="number">0 </span>{
|
||
<a href=#316 id=316 data-nosnippet>316</a> offset -= <span class="number">1</span>;
|
||
<a href=#317 id=317 data-nosnippet>317</a>
|
||
<a href=#318 id=318 data-nosnippet>318</a> <span class="comment">// Either the compiler sees that remain < 10, or it prevents
|
||
<a href=#319 id=319 data-nosnippet>319</a> // a boundary check up next.
|
||
<a href=#320 id=320 data-nosnippet>320</a> </span><span class="kw">let </span>last = remain <span class="kw">as </span>u8 & <span class="number">15</span>;
|
||
<a href=#321 id=321 data-nosnippet>321</a> buf[offset].write(<span class="string">b'0' </span>+ last);
|
||
<a href=#322 id=322 data-nosnippet>322</a> <span class="comment">// not used: remain = 0;
|
||
<a href=#323 id=323 data-nosnippet>323</a> </span>}
|
||
<a href=#324 id=324 data-nosnippet>324</a>
|
||
<a href=#325 id=325 data-nosnippet>325</a> offset
|
||
<a href=#326 id=326 data-nosnippet>326</a> }
|
||
<a href=#327 id=327 data-nosnippet>327</a> }
|
||
<a href=#328 id=328 data-nosnippet>328</a> };
|
||
<a href=#329 id=329 data-nosnippet>329</a>}
|
||
<a href=#330 id=330 data-nosnippet>330</a>
|
||
<a href=#331 id=331 data-nosnippet>331</a><span class="macro">impl_Unsigned!</span>(u8);
|
||
<a href=#332 id=332 data-nosnippet>332</a><span class="macro">impl_Unsigned!</span>(u16);
|
||
<a href=#333 id=333 data-nosnippet>333</a><span class="macro">impl_Unsigned!</span>(u32);
|
||
<a href=#334 id=334 data-nosnippet>334</a><span class="macro">impl_Unsigned!</span>(u64);
|
||
<a href=#335 id=335 data-nosnippet>335</a>
|
||
<a href=#336 id=336 data-nosnippet>336</a><span class="kw">impl </span>Unsigned <span class="kw">for </span>u128 {
|
||
<a href=#337 id=337 data-nosnippet>337</a> <span class="attr">#[cfg_attr(feature = <span class="string">"no-panic"</span>, no_panic)]
|
||
<a href=#338 id=338 data-nosnippet>338</a> </span><span class="kw">fn </span>fmt(<span class="self">self</span>, buf: <span class="kw-2">&mut </span><span class="self">Self</span>::Buffer) -> usize {
|
||
<a href=#339 id=339 data-nosnippet>339</a> <span class="comment">// Optimize common-case zero, which would also need special treatment due to
|
||
<a href=#340 id=340 data-nosnippet>340</a> // its "leading" zero.
|
||
<a href=#341 id=341 data-nosnippet>341</a> </span><span class="kw">if </span><span class="self">self </span>== <span class="number">0 </span>{
|
||
<a href=#342 id=342 data-nosnippet>342</a> <span class="kw">let </span>offset = buf.len() - <span class="number">1</span>;
|
||
<a href=#343 id=343 data-nosnippet>343</a> buf[offset].write(<span class="string">b'0'</span>);
|
||
<a href=#344 id=344 data-nosnippet>344</a> <span class="kw">return </span>offset;
|
||
<a href=#345 id=345 data-nosnippet>345</a> }
|
||
<a href=#346 id=346 data-nosnippet>346</a> <span class="comment">// Take the 16 least-significant decimals.
|
||
<a href=#347 id=347 data-nosnippet>347</a> </span><span class="kw">let </span>(quot_1e16, mod_1e16) = div_rem_1e16(<span class="self">self</span>);
|
||
<a href=#348 id=348 data-nosnippet>348</a> <span class="kw">let </span>(<span class="kw-2">mut </span>remain, <span class="kw-2">mut </span>offset) = <span class="kw">if </span>quot_1e16 == <span class="number">0 </span>{
|
||
<a href=#349 id=349 data-nosnippet>349</a> (mod_1e16, u128::MAX_STR_LEN)
|
||
<a href=#350 id=350 data-nosnippet>350</a> } <span class="kw">else </span>{
|
||
<a href=#351 id=351 data-nosnippet>351</a> <span class="comment">// Write digits at buf[23..39].
|
||
<a href=#352 id=352 data-nosnippet>352</a> </span>enc_16lsd::<{ u128::MAX_STR_LEN - <span class="number">16 </span>}>(buf, mod_1e16);
|
||
<a href=#353 id=353 data-nosnippet>353</a>
|
||
<a href=#354 id=354 data-nosnippet>354</a> <span class="comment">// Take another 16 decimals.
|
||
<a href=#355 id=355 data-nosnippet>355</a> </span><span class="kw">let </span>(quot2, mod2) = div_rem_1e16(quot_1e16);
|
||
<a href=#356 id=356 data-nosnippet>356</a> <span class="kw">if </span>quot2 == <span class="number">0 </span>{
|
||
<a href=#357 id=357 data-nosnippet>357</a> (mod2, u128::MAX_STR_LEN - <span class="number">16</span>)
|
||
<a href=#358 id=358 data-nosnippet>358</a> } <span class="kw">else </span>{
|
||
<a href=#359 id=359 data-nosnippet>359</a> <span class="comment">// Write digits at buf[7..23].
|
||
<a href=#360 id=360 data-nosnippet>360</a> </span>enc_16lsd::<{ u128::MAX_STR_LEN - <span class="number">32 </span>}>(buf, mod2);
|
||
<a href=#361 id=361 data-nosnippet>361</a> <span class="comment">// Quot2 has at most 7 decimals remaining after two 1e16 divisions.
|
||
<a href=#362 id=362 data-nosnippet>362</a> </span>(quot2 <span class="kw">as </span>u64, u128::MAX_STR_LEN - <span class="number">32</span>)
|
||
<a href=#363 id=363 data-nosnippet>363</a> }
|
||
<a href=#364 id=364 data-nosnippet>364</a> };
|
||
<a href=#365 id=365 data-nosnippet>365</a>
|
||
<a href=#366 id=366 data-nosnippet>366</a> <span class="comment">// Format per four digits from the lookup table.
|
||
<a href=#367 id=367 data-nosnippet>367</a> </span><span class="kw">while </span>remain > <span class="number">999 </span>{
|
||
<a href=#368 id=368 data-nosnippet>368</a> offset -= <span class="number">4</span>;
|
||
<a href=#369 id=369 data-nosnippet>369</a>
|
||
<a href=#370 id=370 data-nosnippet>370</a> <span class="comment">// pull two pairs
|
||
<a href=#371 id=371 data-nosnippet>371</a> </span><span class="kw">let </span>quad = remain % <span class="number">1_00_00</span>;
|
||
<a href=#372 id=372 data-nosnippet>372</a> remain /= <span class="number">1_00_00</span>;
|
||
<a href=#373 id=373 data-nosnippet>373</a> <span class="kw">let </span>(pair1, pair2) = divmod100(quad <span class="kw">as </span>u32);
|
||
<a href=#374 id=374 data-nosnippet>374</a> <span class="kw">unsafe </span>{
|
||
<a href=#375 id=375 data-nosnippet>375</a> buf[offset + <span class="number">0</span>].write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair1 <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">0</span>));
|
||
<a href=#376 id=376 data-nosnippet>376</a> buf[offset + <span class="number">1</span>].write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair1 <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">1</span>));
|
||
<a href=#377 id=377 data-nosnippet>377</a> buf[offset + <span class="number">2</span>].write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair2 <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">0</span>));
|
||
<a href=#378 id=378 data-nosnippet>378</a> buf[offset + <span class="number">3</span>].write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair2 <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">1</span>));
|
||
<a href=#379 id=379 data-nosnippet>379</a> }
|
||
<a href=#380 id=380 data-nosnippet>380</a> }
|
||
<a href=#381 id=381 data-nosnippet>381</a>
|
||
<a href=#382 id=382 data-nosnippet>382</a> <span class="comment">// Format per two digits from the lookup table.
|
||
<a href=#383 id=383 data-nosnippet>383</a> </span><span class="kw">if </span>remain > <span class="number">9 </span>{
|
||
<a href=#384 id=384 data-nosnippet>384</a> offset -= <span class="number">2</span>;
|
||
<a href=#385 id=385 data-nosnippet>385</a>
|
||
<a href=#386 id=386 data-nosnippet>386</a> <span class="kw">let </span>(last, pair) = divmod100(remain <span class="kw">as </span>u32);
|
||
<a href=#387 id=387 data-nosnippet>387</a> remain = last <span class="kw">as </span>u64;
|
||
<a href=#388 id=388 data-nosnippet>388</a> <span class="kw">unsafe </span>{
|
||
<a href=#389 id=389 data-nosnippet>389</a> buf[offset + <span class="number">0</span>].write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">0</span>));
|
||
<a href=#390 id=390 data-nosnippet>390</a> buf[offset + <span class="number">1</span>].write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">1</span>));
|
||
<a href=#391 id=391 data-nosnippet>391</a> }
|
||
<a href=#392 id=392 data-nosnippet>392</a> }
|
||
<a href=#393 id=393 data-nosnippet>393</a>
|
||
<a href=#394 id=394 data-nosnippet>394</a> <span class="comment">// Format the last remaining digit, if any.
|
||
<a href=#395 id=395 data-nosnippet>395</a> </span><span class="kw">if </span><span class="macro">remain !</span>= <span class="number">0 </span>{
|
||
<a href=#396 id=396 data-nosnippet>396</a> offset -= <span class="number">1</span>;
|
||
<a href=#397 id=397 data-nosnippet>397</a>
|
||
<a href=#398 id=398 data-nosnippet>398</a> <span class="comment">// Either the compiler sees that remain < 10, or it prevents
|
||
<a href=#399 id=399 data-nosnippet>399</a> // a boundary check up next.
|
||
<a href=#400 id=400 data-nosnippet>400</a> </span><span class="kw">let </span>last = remain <span class="kw">as </span>u8 & <span class="number">15</span>;
|
||
<a href=#401 id=401 data-nosnippet>401</a> buf[offset].write(<span class="string">b'0' </span>+ last);
|
||
<a href=#402 id=402 data-nosnippet>402</a> <span class="comment">// not used: remain = 0;
|
||
<a href=#403 id=403 data-nosnippet>403</a> </span>}
|
||
<a href=#404 id=404 data-nosnippet>404</a> offset
|
||
<a href=#405 id=405 data-nosnippet>405</a> }
|
||
<a href=#406 id=406 data-nosnippet>406</a>}
|
||
<a href=#407 id=407 data-nosnippet>407</a>
|
||
<a href=#408 id=408 data-nosnippet>408</a><span class="comment">// Encodes the 16 least-significant decimals of n into `buf[OFFSET..OFFSET + 16]`.
|
||
<a href=#409 id=409 data-nosnippet>409</a></span><span class="attr">#[cfg_attr(feature = <span class="string">"no-panic"</span>, no_panic)]
|
||
<a href=#410 id=410 data-nosnippet>410</a></span><span class="kw">fn </span>enc_16lsd<<span class="kw">const </span>OFFSET: usize>(buf: <span class="kw-2">&mut </span>[MaybeUninit<u8>], n: u64) {
|
||
<a href=#411 id=411 data-nosnippet>411</a> <span class="comment">// Consume the least-significant decimals from a working copy.
|
||
<a href=#412 id=412 data-nosnippet>412</a> </span><span class="kw">let </span><span class="kw-2">mut </span>remain = n;
|
||
<a href=#413 id=413 data-nosnippet>413</a>
|
||
<a href=#414 id=414 data-nosnippet>414</a> <span class="comment">// Format per four digits from the lookup table.
|
||
<a href=#415 id=415 data-nosnippet>415</a> </span><span class="kw">for </span>quad_index <span class="kw">in </span>(<span class="number">0</span>..<span class="number">4</span>).rev() {
|
||
<a href=#416 id=416 data-nosnippet>416</a> <span class="comment">// pull two pairs
|
||
<a href=#417 id=417 data-nosnippet>417</a> </span><span class="kw">let </span>quad = remain % <span class="number">1_00_00</span>;
|
||
<a href=#418 id=418 data-nosnippet>418</a> remain /= <span class="number">1_00_00</span>;
|
||
<a href=#419 id=419 data-nosnippet>419</a> <span class="kw">let </span>(pair1, pair2) = divmod100(quad <span class="kw">as </span>u32);
|
||
<a href=#420 id=420 data-nosnippet>420</a> <span class="kw">unsafe </span>{
|
||
<a href=#421 id=421 data-nosnippet>421</a> buf[quad_index * <span class="number">4 </span>+ OFFSET + <span class="number">0</span>]
|
||
<a href=#422 id=422 data-nosnippet>422</a> .write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair1 <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">0</span>));
|
||
<a href=#423 id=423 data-nosnippet>423</a> buf[quad_index * <span class="number">4 </span>+ OFFSET + <span class="number">1</span>]
|
||
<a href=#424 id=424 data-nosnippet>424</a> .write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair1 <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">1</span>));
|
||
<a href=#425 id=425 data-nosnippet>425</a> buf[quad_index * <span class="number">4 </span>+ OFFSET + <span class="number">2</span>]
|
||
<a href=#426 id=426 data-nosnippet>426</a> .write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair2 <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">0</span>));
|
||
<a href=#427 id=427 data-nosnippet>427</a> buf[quad_index * <span class="number">4 </span>+ OFFSET + <span class="number">3</span>]
|
||
<a href=#428 id=428 data-nosnippet>428</a> .write(<span class="kw-2">*</span>DECIMAL_PAIRS.<span class="number">0</span>.get_unchecked(pair2 <span class="kw">as </span>usize * <span class="number">2 </span>+ <span class="number">1</span>));
|
||
<a href=#429 id=429 data-nosnippet>429</a> }
|
||
<a href=#430 id=430 data-nosnippet>430</a> }
|
||
<a href=#431 id=431 data-nosnippet>431</a>}
|
||
<a href=#432 id=432 data-nosnippet>432</a>
|
||
<a href=#433 id=433 data-nosnippet>433</a><span class="comment">// Euclidean division plus remainder with constant 1E16 basically consumes 16
|
||
<a href=#434 id=434 data-nosnippet>434</a>// decimals from n.
|
||
<a href=#435 id=435 data-nosnippet>435</a>//
|
||
<a href=#436 id=436 data-nosnippet>436</a>// The integer division algorithm is based on the following paper:
|
||
<a href=#437 id=437 data-nosnippet>437</a>//
|
||
<a href=#438 id=438 data-nosnippet>438</a>// T. Granlund and P. Montgomery, “Division by Invariant Integers Using Multiplication”
|
||
<a href=#439 id=439 data-nosnippet>439</a>// in Proc. of the SIGPLAN94 Conference on Programming Language Design and
|
||
<a href=#440 id=440 data-nosnippet>440</a>// Implementation, 1994, pp. 61–72
|
||
<a href=#441 id=441 data-nosnippet>441</a>//
|
||
<a href=#442 id=442 data-nosnippet>442</a></span><span class="attr">#[cfg_attr(feature = <span class="string">"no-panic"</span>, no_panic)]
|
||
<a href=#443 id=443 data-nosnippet>443</a></span><span class="kw">fn </span>div_rem_1e16(n: u128) -> (u128, u64) {
|
||
<a href=#444 id=444 data-nosnippet>444</a> <span class="kw">const </span>D: u128 = <span class="number">1_0000_0000_0000_0000</span>;
|
||
<a href=#445 id=445 data-nosnippet>445</a> <span class="comment">// The check inlines well with the caller flow.
|
||
<a href=#446 id=446 data-nosnippet>446</a> </span><span class="kw">if </span>n < D {
|
||
<a href=#447 id=447 data-nosnippet>447</a> <span class="kw">return </span>(<span class="number">0</span>, n <span class="kw">as </span>u64);
|
||
<a href=#448 id=448 data-nosnippet>448</a> }
|
||
<a href=#449 id=449 data-nosnippet>449</a>
|
||
<a href=#450 id=450 data-nosnippet>450</a> <span class="comment">// These constant values are computed with the CHOOSE_MULTIPLIER procedure
|
||
<a href=#451 id=451 data-nosnippet>451</a> // from the Granlund & Montgomery paper, using N=128, prec=128 and d=1E16.
|
||
<a href=#452 id=452 data-nosnippet>452</a> </span><span class="kw">const </span>M_HIGH: u128 = <span class="number">76624777043294442917917351357515459181</span>;
|
||
<a href=#453 id=453 data-nosnippet>453</a> <span class="kw">const </span>SH_POST: u8 = <span class="number">51</span>;
|
||
<a href=#454 id=454 data-nosnippet>454</a>
|
||
<a href=#455 id=455 data-nosnippet>455</a> <span class="comment">// n.widening_mul(M_HIGH).1 >> SH_POST
|
||
<a href=#456 id=456 data-nosnippet>456</a> </span><span class="kw">let </span>quot = u128_ext::mulhi(n, M_HIGH) >> SH_POST;
|
||
<a href=#457 id=457 data-nosnippet>457</a> <span class="kw">let </span>rem = n - quot * D;
|
||
<a href=#458 id=458 data-nosnippet>458</a> (quot, rem <span class="kw">as </span>u64)
|
||
<a href=#459 id=459 data-nosnippet>459</a>}
|
||
</code></pre></div></section></main></body></html> |