1 <!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="Trait describing an integer type which can be used as a “packed” sequence of Fe32s."><title>PackedFe32 in bdk_chain::bitcoin::bech32::primitives::checksum - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-46f98efaafac5295.ttf.woff2,FiraSans-Regular-018c141bf0843ffd.woff2,FiraSans-Medium-8f9a781e4970d388.woff2,SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2,SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../../../../../static.files/normalize-76eba96aa4d2e634.css"><link rel="stylesheet" href="../../../../../static.files/rustdoc-dd39b87e5fcfba68.css"><meta name="rustdoc-vars" data-root-path="../../../../../" data-static-root-path="../../../../../static.files/" data-current-crate="bdk_chain" data-themes="" data-resource-suffix="" data-rustdoc-version="1.80.0-nightly (78a775127 2024-05-11)" data-channel="nightly" data-search-js="search-d52510db62a78183.js" data-settings-js="settings-4313503d2e1961c2.js" ><script src="../../../../../static.files/storage-118b08c4c78b968e.js"></script><script defer src="sidebar-items.js"></script><script defer src="../../../../../static.files/main-20a3ad099b048cf2.js"></script><noscript><link rel="stylesheet" href="../../../../../static.files/noscript-df360f571f6edeae.css"></noscript><link rel="alternate icon" type="image/png" href="../../../../../static.files/favicon-32x32-422f7d1d52889060.png"><link rel="icon" type="image/svg+xml" href="../../../../../static.files/favicon-2c020d218678b618.svg"></head><body class="rustdoc trait"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle" title="show sidebar"></button><a class="logo-container" href="../../../../../bdk_chain/index.html"><img src="https://github.com/bitcoindevkit/bdk/raw/master/static/bdk.png" alt=""></a></nav><nav class="sidebar"><div class="sidebar-crate"><a class="logo-container" href="../../../../../bdk_chain/index.html"><img src="https://github.com/bitcoindevkit/bdk/raw/master/static/bdk.png" alt="logo"></a><h2><a href="../../../../../bdk_chain/index.html">bdk_chain</a><span class="version">0.20.0</span></h2></div><h2 class="location"><a href="#">PackedFe32</a></h2><div class="sidebar-elems"><section><h3><a href="#required-associated-consts">Required Associated Constants</a></h3><ul class="block"><li><a href="#associatedconstant.ONE">ONE</a></li></ul><h3><a href="#provided-associated-consts">Provided Associated Constants</a></h3><ul class="block"><li><a href="#associatedconstant.WIDTH">WIDTH</a></li></ul><h3><a href="#required-methods">Required Methods</a></h3><ul class="block"><li><a href="#tymethod.mul_by_x_then_add">mul_by_x_then_add</a></li><li><a href="#tymethod.unpack">unpack</a></li></ul><h3><a href="#foreign-impls">Implementations on Foreign Types</a></h3><ul class="block"><li><a href="#impl-PackedFe32-for-u128">u128</a></li><li><a href="#impl-PackedFe32-for-u32">u32</a></li><li><a href="#impl-PackedFe32-for-u64">u64</a></li></ul><h3><a href="#object-safety">Object Safety</a></h3><h3><a href="#implementors">Implementors</a></h3></section><h2><a href="index.html">In bdk_chain::bitcoin::bech32::primitives::checksum</a></h2></div></nav><div class="sidebar-resizer"></div><main><div class="width-limiter"><rustdoc-search></rustdoc-search><section id="main-content" class="content"><div class="main-heading"><h1>Trait <a href="../../../../index.html">bdk_chain</a>::<wbr><a href="../../../index.html">bitcoin</a>::<wbr><a href="../../index.html">bech32</a>::<wbr><a href="../index.html">primitives</a>::<wbr><a href="index.html">checksum</a>::<wbr><a class="trait" href="#">PackedFe32</a><button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><span class="out-of-band"><button id="toggle-all-docs" title="collapse all docs">[<span>−</span>]</button></span></div><pre class="rust item-decl"><code>pub trait PackedFe32: <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Copy.html" title="trait core::marker::Copy">Copy</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html" title="trait core::cmp::PartialEq">PartialEq</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/ops/bit/trait.BitXor.html" title="trait core::ops::bit::BitXor">BitXor</a><Output = Self> {
2 const <a href="#associatedconstant.ONE" class="constant">ONE</a>: Self;
3 const <a href="#associatedconstant.WIDTH" class="constant">WIDTH</a>: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a> = _;
6 fn <a href="#tymethod.unpack" class="fn">unpack</a>(&self, n: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a>;
7 <span class="item-spacer"></span> fn <a href="#tymethod.mul_by_x_then_add" class="fn">mul_by_x_then_add</a>(&mut self, degree: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>, add: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a>) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a>;
8 }</code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Trait describing an integer type which can be used as a “packed” sequence of Fe32s.</p>
9 <p>This is implemented for u32, u64 and u128, as a way to treat these primitive types as
10 packed coefficients of polynomials over GF32 (up to some maximal degree, of course).</p>
11 <p>This is useful because then multiplication by x reduces to simply left-shifting by 5,
12 and addition of entire polynomials can be done by xor.</p>
13 </div></details><h2 id="required-associated-consts" class="section-header">Required Associated Constants<a href="#required-associated-consts" class="anchor">§</a></h2><div class="methods"><details class="toggle" open><summary><section id="associatedconstant.ONE" class="method"><h4 class="code-header">const <a href="#associatedconstant.ONE" class="constant">ONE</a>: Self</h4></section></summary><div class="docblock"><p>The one constant, for which stdlib provides no existing trait.</p>
14 </div></details></div><h2 id="provided-associated-consts" class="section-header">Provided Associated Constants<a href="#provided-associated-consts" class="anchor">§</a></h2><div class="methods"><details class="toggle" open><summary><section id="associatedconstant.WIDTH" class="method"><h4 class="code-header">const <a href="#associatedconstant.WIDTH" class="constant">WIDTH</a>: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a> = _</h4></section></summary><div class="docblock"><p>The number of fe32s that can fit into the type; computed as floor(bitwidth / 5).</p>
15 </div></details></div><h2 id="required-methods" class="section-header">Required Methods<a href="#required-methods" class="anchor">§</a></h2><div class="methods"><details class="toggle method-toggle" open><summary><section id="tymethod.unpack" class="method"><h4 class="code-header">fn <a href="#tymethod.unpack" class="fn">unpack</a>(&self, n: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a></h4></section></summary><div class="docblock"><p>Extracts the coefficient of the x^n from the packed polynomial.</p>
16 </div></details><details class="toggle method-toggle" open><summary><section id="tymethod.mul_by_x_then_add" class="method"><h4 class="code-header">fn <a href="#tymethod.mul_by_x_then_add" class="fn">mul_by_x_then_add</a>(&mut self, degree: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>, add: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a>) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a></h4></section></summary><div class="docblock"><p>Multiply the polynomial by x, drop its highest coefficient (and return it), and
17 add a new field element to the now-0 constant coefficient.</p>
18 <p>Takes the degree of the polynomial as an input; for checksum applications
19 this should basically always be <code>Checksum::CHECKSUM_WIDTH</code>.</p>
20 </div></details></div><h2 id="object-safety" class="section-header">Object Safety<a href="#object-safety" class="anchor">§</a></h2><div class="object-safety-info">This trait is <b>not</b> <a href="https://doc.rust-lang.org/nightly/reference/items/traits.html#object-safety">object safe</a>.</div><h2 id="foreign-impls" class="section-header">Implementations on Foreign Types<a href="#foreign-impls" class="anchor">§</a></h2><details class="toggle implementors-toggle"><summary><section id="impl-PackedFe32-for-u32" class="impl"><a href="#impl-PackedFe32-for-u32" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="trait.PackedFe32.html" title="trait bdk_chain::bitcoin::bech32::primitives::checksum::PackedFe32">PackedFe32</a> for <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u32.html">u32</a></h3></section></summary><div class="impl-items"><section id="associatedconstant.ONE-1" class="associatedconstant trait-impl"><a href="#associatedconstant.ONE-1" class="anchor">§</a><h4 class="code-header">const <a href="#associatedconstant.ONE" class="constant">ONE</a>: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u32.html">u32</a> = 1u32</h4></section><section id="method.unpack" class="method trait-impl"><a href="#method.unpack" class="anchor">§</a><h4 class="code-header">fn <a href="#tymethod.unpack" class="fn">unpack</a>(&self, n: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a></h4></section><section id="method.mul_by_x_then_add" class="method trait-impl"><a href="#method.mul_by_x_then_add" class="anchor">§</a><h4 class="code-header">fn <a href="#tymethod.mul_by_x_then_add" class="fn">mul_by_x_then_add</a>(&mut self, degree: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>, add: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a>) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a></h4></section></div></details><details class="toggle implementors-toggle"><summary><section id="impl-PackedFe32-for-u64" class="impl"><a href="#impl-PackedFe32-for-u64" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="trait.PackedFe32.html" title="trait bdk_chain::bitcoin::bech32::primitives::checksum::PackedFe32">PackedFe32</a> for <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u64.html">u64</a></h3></section></summary><div class="impl-items"><section id="associatedconstant.ONE-2" class="associatedconstant trait-impl"><a href="#associatedconstant.ONE-2" class="anchor">§</a><h4 class="code-header">const <a href="#associatedconstant.ONE" class="constant">ONE</a>: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u64.html">u64</a> = 1u64</h4></section><section id="method.unpack-1" class="method trait-impl"><a href="#method.unpack-1" class="anchor">§</a><h4 class="code-header">fn <a href="#tymethod.unpack" class="fn">unpack</a>(&self, n: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a></h4></section><section id="method.mul_by_x_then_add-1" class="method trait-impl"><a href="#method.mul_by_x_then_add-1" class="anchor">§</a><h4 class="code-header">fn <a href="#tymethod.mul_by_x_then_add" class="fn">mul_by_x_then_add</a>(&mut self, degree: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>, add: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a>) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a></h4></section></div></details><details class="toggle implementors-toggle"><summary><section id="impl-PackedFe32-for-u128" class="impl"><a href="#impl-PackedFe32-for-u128" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="trait.PackedFe32.html" title="trait bdk_chain::bitcoin::bech32::primitives::checksum::PackedFe32">PackedFe32</a> for <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u128.html">u128</a></h3></section></summary><div class="impl-items"><section id="associatedconstant.ONE-3" class="associatedconstant trait-impl"><a href="#associatedconstant.ONE-3" class="anchor">§</a><h4 class="code-header">const <a href="#associatedconstant.ONE" class="constant">ONE</a>: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u128.html">u128</a> = 1u128</h4></section><section id="method.unpack-2" class="method trait-impl"><a href="#method.unpack-2" class="anchor">§</a><h4 class="code-header">fn <a href="#tymethod.unpack" class="fn">unpack</a>(&self, n: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a></h4></section><section id="method.mul_by_x_then_add-2" class="method trait-impl"><a href="#method.mul_by_x_then_add-2" class="anchor">§</a><h4 class="code-header">fn <a href="#tymethod.mul_by_x_then_add" class="fn">mul_by_x_then_add</a>(&mut self, degree: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>, add: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a>) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u8.html">u8</a></h4></section></div></details><h2 id="implementors" class="section-header">Implementors<a href="#implementors" class="anchor">§</a></h2><div id="implementors-list"><details class="toggle implementors-toggle"><summary><section id="impl-PackedFe32-for-PackedNull" class="impl"><a href="#impl-PackedFe32-for-PackedNull" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="trait.PackedFe32.html" title="trait bdk_chain::bitcoin::bech32::primitives::checksum::PackedFe32">PackedFe32</a> for <a class="struct" href="struct.PackedNull.html" title="struct bdk_chain::bitcoin::bech32::primitives::checksum::PackedNull">PackedNull</a></h3></section></summary><div class="impl-items"><section id="associatedconstant.ONE-4" class="associatedconstant trait-impl"><a href="#associatedconstant.ONE-4" class="anchor">§</a><h4 class="code-header">const <a href="#associatedconstant.ONE" class="constant">ONE</a>: <a class="struct" href="struct.PackedNull.html" title="struct bdk_chain::bitcoin::bech32::primitives::checksum::PackedNull">PackedNull</a> = PackedNull</h4></section></div></details></div><script src="../../../../../trait.impl/bech32/primitives/checksum/trait.PackedFe32.js" data-ignore-extern-crates="std,bech32" 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