| <!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 `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/idna-0.3.0/src/punycode.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>punycode.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../normalize.css"><link rel="stylesheet" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../ayu.css" disabled><link rel="stylesheet" href="../../dark.css" disabled><link rel="stylesheet" href="../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../storage.js"></script><script defer src="../../source-script.js"></script><script defer src="../../source-files.js"></script><script defer src="../../main.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../idna/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../idna/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code><span class="comment">// Copyright 2013 The rust-url developers. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| </span><span class="doccomment">//! Punycode ([RFC 3492](http://tools.ietf.org/html/rfc3492)) implementation. |
| //! |
| //! Since Punycode fundamentally works on unicode code points, |
| //! `encode` and `decode` take and return slices and vectors of `char`. |
| //! `encode_str` and `decode_to_string` provide convenience wrappers |
| //! that convert from and to Rust’s UTF-8 based `str` and `String` types. |
| |
| </span><span class="kw">use </span>std::char; |
| <span class="kw">use </span>std::u32; |
| |
| <span class="comment">// Bootstring parameters for Punycode |
| </span><span class="kw">static </span>BASE: u32 = <span class="number">36</span>; |
| <span class="kw">static </span>T_MIN: u32 = <span class="number">1</span>; |
| <span class="kw">static </span>T_MAX: u32 = <span class="number">26</span>; |
| <span class="kw">static </span>SKEW: u32 = <span class="number">38</span>; |
| <span class="kw">static </span>DAMP: u32 = <span class="number">700</span>; |
| <span class="kw">static </span>INITIAL_BIAS: u32 = <span class="number">72</span>; |
| <span class="kw">static </span>INITIAL_N: u32 = <span class="number">0x80</span>; |
| <span class="kw">static </span>DELIMITER: char = <span class="string">'-'</span>; |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>adapt(<span class="kw-2">mut </span>delta: u32, num_points: u32, first_time: bool) -> u32 { |
| delta /= <span class="kw">if </span>first_time { DAMP } <span class="kw">else </span>{ <span class="number">2 </span>}; |
| delta += delta / num_points; |
| <span class="kw">let </span><span class="kw-2">mut </span>k = <span class="number">0</span>; |
| <span class="kw">while </span>delta > ((BASE - T_MIN) * T_MAX) / <span class="number">2 </span>{ |
| delta /= BASE - T_MIN; |
| k += BASE; |
| } |
| k + (((BASE - T_MIN + <span class="number">1</span>) * delta) / (delta + SKEW)) |
| } |
| |
| <span class="doccomment">/// Convert Punycode to an Unicode `String`. |
| /// |
| /// This is a convenience wrapper around `decode`. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>decode_to_string(input: <span class="kw-2">&</span>str) -> <span class="prelude-ty">Option</span><String> { |
| decode(input).map(|chars| chars.into_iter().collect()) |
| } |
| |
| <span class="doccomment">/// Convert Punycode to Unicode. |
| /// |
| /// Return None on malformed input or overflow. |
| /// Overflow can only happen on inputs that take more than |
| /// 63 encoded bytes, the DNS limit on domain name labels. |
| </span><span class="kw">pub fn </span>decode(input: <span class="kw-2">&</span>str) -> <span class="prelude-ty">Option</span><Vec<char>> { |
| <span class="prelude-val">Some</span>(Decoder::default().decode(input).ok()<span class="question-mark">?</span>.collect()) |
| } |
| |
| <span class="attribute">#[derive(Default)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>Decoder { |
| insertions: Vec<(usize, char)>, |
| } |
| |
| <span class="kw">impl </span>Decoder { |
| <span class="doccomment">/// Split the input iterator and return a Vec with insertions of encoded characters |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>decode<<span class="lifetime">'a</span>>(<span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span><span class="self">self</span>, input: <span class="kw-2">&</span><span class="lifetime">'a </span>str) -> <span class="prelude-ty">Result</span><Decode<<span class="lifetime">'a</span>>, ()> { |
| <span class="self">self</span>.insertions.clear(); |
| <span class="comment">// Handle "basic" (ASCII) code points. |
| // They are encoded as-is before the last delimiter, if any. |
| </span><span class="kw">let </span>(base, input) = <span class="kw">match </span>input.rfind(DELIMITER) { |
| <span class="prelude-val">None </span>=> (<span class="string">""</span>, input), |
| <span class="prelude-val">Some</span>(position) => ( |
| <span class="kw-2">&</span>input[..position], |
| <span class="kw">if </span>position > <span class="number">0 </span>{ |
| <span class="kw-2">&</span>input[position + <span class="number">1</span>..] |
| } <span class="kw">else </span>{ |
| input |
| }, |
| ), |
| }; |
| |
| <span class="kw">if </span>!base.is_ascii() { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(()); |
| } |
| |
| <span class="kw">let </span>base_len = base.len(); |
| <span class="kw">let </span><span class="kw-2">mut </span>length = base_len <span class="kw">as </span>u32; |
| <span class="kw">let </span><span class="kw-2">mut </span>code_point = INITIAL_N; |
| <span class="kw">let </span><span class="kw-2">mut </span>bias = INITIAL_BIAS; |
| <span class="kw">let </span><span class="kw-2">mut </span>i = <span class="number">0</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>iter = input.bytes(); |
| <span class="kw">loop </span>{ |
| <span class="kw">let </span>previous_i = i; |
| <span class="kw">let </span><span class="kw-2">mut </span>weight = <span class="number">1</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>k = BASE; |
| <span class="kw">let </span><span class="kw-2">mut </span>byte = <span class="kw">match </span>iter.next() { |
| <span class="prelude-val">None </span>=> <span class="kw">break</span>, |
| <span class="prelude-val">Some</span>(byte) => byte, |
| }; |
| |
| <span class="comment">// Decode a generalized variable-length integer into delta, |
| // which gets added to i. |
| </span><span class="kw">loop </span>{ |
| <span class="kw">let </span>digit = <span class="kw">match </span>byte { |
| byte @ <span class="string">b'0'</span>..=<span class="string">b'9' </span>=> byte - <span class="string">b'0' </span>+ <span class="number">26</span>, |
| byte @ <span class="string">b'A'</span>..=<span class="string">b'Z' </span>=> byte - <span class="string">b'A'</span>, |
| byte @ <span class="string">b'a'</span>..=<span class="string">b'z' </span>=> byte - <span class="string">b'a'</span>, |
| <span class="kw">_ </span>=> <span class="kw">return </span><span class="prelude-val">Err</span>(()), |
| } <span class="kw">as </span>u32; |
| <span class="kw">if </span>digit > (u32::MAX - i) / weight { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(()); <span class="comment">// Overflow |
| </span>} |
| i += digit * weight; |
| <span class="kw">let </span>t = <span class="kw">if </span>k <= bias { |
| T_MIN |
| } <span class="kw">else if </span>k >= bias + T_MAX { |
| T_MAX |
| } <span class="kw">else </span>{ |
| k - bias |
| }; |
| <span class="kw">if </span>digit < t { |
| <span class="kw">break</span>; |
| } |
| <span class="kw">if </span>weight > u32::MAX / (BASE - t) { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(()); <span class="comment">// Overflow |
| </span>} |
| weight <span class="kw-2">*</span>= BASE - t; |
| k += BASE; |
| byte = <span class="kw">match </span>iter.next() { |
| <span class="prelude-val">None </span>=> <span class="kw">return </span><span class="prelude-val">Err</span>(()), <span class="comment">// End of input before the end of this delta |
| </span><span class="prelude-val">Some</span>(byte) => byte, |
| }; |
| } |
| |
| bias = adapt(i - previous_i, length + <span class="number">1</span>, previous_i == <span class="number">0</span>); |
| <span class="kw">if </span>i / (length + <span class="number">1</span>) > u32::MAX - code_point { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(()); <span class="comment">// Overflow |
| </span>} |
| |
| <span class="comment">// i was supposed to wrap around from length+1 to 0, |
| // incrementing code_point each time. |
| </span>code_point += i / (length + <span class="number">1</span>); |
| i %= length + <span class="number">1</span>; |
| <span class="kw">let </span>c = <span class="kw">match </span>char::from_u32(code_point) { |
| <span class="prelude-val">Some</span>(c) => c, |
| <span class="prelude-val">None </span>=> <span class="kw">return </span><span class="prelude-val">Err</span>(()), |
| }; |
| |
| <span class="comment">// Move earlier insertions farther out in the string |
| </span><span class="kw">for </span>(idx, <span class="kw">_</span>) <span class="kw">in </span><span class="kw-2">&mut </span><span class="self">self</span>.insertions { |
| <span class="kw">if </span><span class="kw-2">*</span>idx >= i <span class="kw">as </span>usize { |
| <span class="kw-2">*</span>idx += <span class="number">1</span>; |
| } |
| } |
| <span class="self">self</span>.insertions.push((i <span class="kw">as </span>usize, c)); |
| length += <span class="number">1</span>; |
| i += <span class="number">1</span>; |
| } |
| |
| <span class="self">self</span>.insertions.sort_by_key(|(i, <span class="kw">_</span>)| <span class="kw-2">*</span>i); |
| <span class="prelude-val">Ok</span>(Decode { |
| base: base.chars(), |
| insertions: <span class="kw-2">&</span><span class="self">self</span>.insertions, |
| inserted: <span class="number">0</span>, |
| position: <span class="number">0</span>, |
| len: base_len + <span class="self">self</span>.insertions.len(), |
| }) |
| } |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>Decode<<span class="lifetime">'a</span>> { |
| base: std::str::Chars<<span class="lifetime">'a</span>>, |
| <span class="kw">pub</span>(<span class="kw">crate</span>) insertions: <span class="kw-2">&</span><span class="lifetime">'a </span>[(usize, char)], |
| inserted: usize, |
| position: usize, |
| len: usize, |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'a</span>> Iterator <span class="kw">for </span>Decode<<span class="lifetime">'a</span>> { |
| <span class="kw">type </span>Item = char; |
| |
| <span class="kw">fn </span>next(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><<span class="self">Self</span>::Item> { |
| <span class="kw">loop </span>{ |
| <span class="kw">match </span><span class="self">self</span>.insertions.get(<span class="self">self</span>.inserted) { |
| <span class="prelude-val">Some</span>((pos, c)) <span class="kw">if </span><span class="kw-2">*</span>pos == <span class="self">self</span>.position => { |
| <span class="self">self</span>.inserted += <span class="number">1</span>; |
| <span class="self">self</span>.position += <span class="number">1</span>; |
| <span class="kw">return </span><span class="prelude-val">Some</span>(<span class="kw-2">*</span>c); |
| } |
| <span class="kw">_ </span>=> {} |
| } |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(c) = <span class="self">self</span>.base.next() { |
| <span class="self">self</span>.position += <span class="number">1</span>; |
| <span class="kw">return </span><span class="prelude-val">Some</span>(c); |
| } <span class="kw">else if </span><span class="self">self</span>.inserted >= <span class="self">self</span>.insertions.len() { |
| <span class="kw">return </span><span class="prelude-val">None</span>; |
| } |
| } |
| } |
| |
| <span class="kw">fn </span>size_hint(<span class="kw-2">&</span><span class="self">self</span>) -> (usize, <span class="prelude-ty">Option</span><usize>) { |
| <span class="kw">let </span>len = <span class="self">self</span>.len - <span class="self">self</span>.position; |
| (len, <span class="prelude-val">Some</span>(len)) |
| } |
| } |
| |
| <span class="kw">impl</span><<span class="lifetime">'a</span>> ExactSizeIterator <span class="kw">for </span>Decode<<span class="lifetime">'a</span>> { |
| <span class="kw">fn </span>len(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <span class="self">self</span>.len - <span class="self">self</span>.position |
| } |
| } |
| |
| <span class="doccomment">/// Convert an Unicode `str` to Punycode. |
| /// |
| /// This is a convenience wrapper around `encode`. |
| </span><span class="attribute">#[inline] |
| </span><span class="kw">pub fn </span>encode_str(input: <span class="kw-2">&</span>str) -> <span class="prelude-ty">Option</span><String> { |
| <span class="kw">let </span><span class="kw-2">mut </span>buf = String::with_capacity(input.len()); |
| encode_into(input.chars(), <span class="kw-2">&mut </span>buf).ok().map(|()| buf) |
| } |
| |
| <span class="doccomment">/// Convert Unicode to Punycode. |
| /// |
| /// Return None on overflow, which can only happen on inputs that would take more than |
| /// 63 encoded bytes, the DNS limit on domain name labels. |
| </span><span class="kw">pub fn </span>encode(input: <span class="kw-2">&</span>[char]) -> <span class="prelude-ty">Option</span><String> { |
| <span class="kw">let </span><span class="kw-2">mut </span>buf = String::with_capacity(input.len()); |
| encode_into(input.iter().copied(), <span class="kw-2">&mut </span>buf) |
| .ok() |
| .map(|()| buf) |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>encode_into<I>(input: I, output: <span class="kw-2">&mut </span>String) -> <span class="prelude-ty">Result</span><(), ()> |
| <span class="kw">where |
| </span>I: Iterator<Item = char> + Clone, |
| { |
| <span class="comment">// Handle "basic" (ASCII) code points. They are encoded as-is. |
| </span><span class="kw">let </span>(<span class="kw-2">mut </span>input_length, <span class="kw-2">mut </span>basic_length) = (<span class="number">0</span>, <span class="number">0</span>); |
| <span class="kw">for </span>c <span class="kw">in </span>input.clone() { |
| input_length += <span class="number">1</span>; |
| <span class="kw">if </span>c.is_ascii() { |
| output.push(c); |
| basic_length += <span class="number">1</span>; |
| } |
| } |
| |
| <span class="kw">if </span>basic_length > <span class="number">0 </span>{ |
| output.push(<span class="string">'-'</span>) |
| } |
| <span class="kw">let </span><span class="kw-2">mut </span>code_point = INITIAL_N; |
| <span class="kw">let </span><span class="kw-2">mut </span>delta = <span class="number">0</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>bias = INITIAL_BIAS; |
| <span class="kw">let </span><span class="kw-2">mut </span>processed = basic_length; |
| <span class="kw">while </span>processed < input_length { |
| <span class="comment">// All code points < code_point have been handled already. |
| // Find the next larger one. |
| </span><span class="kw">let </span>min_code_point = input |
| .clone() |
| .map(|c| c <span class="kw">as </span>u32) |
| .filter(|<span class="kw-2">&</span>c| c >= code_point) |
| .min() |
| .unwrap(); |
| <span class="kw">if </span>min_code_point - code_point > (u32::MAX - delta) / (processed + <span class="number">1</span>) { |
| <span class="kw">return </span><span class="prelude-val">Err</span>(()); <span class="comment">// Overflow |
| </span>} |
| <span class="comment">// Increase delta to advance the decoder’s <code_point,i> state to <min_code_point,0> |
| </span>delta += (min_code_point - code_point) * (processed + <span class="number">1</span>); |
| code_point = min_code_point; |
| <span class="kw">for </span>c <span class="kw">in </span>input.clone() { |
| <span class="kw">let </span>c = c <span class="kw">as </span>u32; |
| <span class="kw">if </span>c < code_point { |
| delta += <span class="number">1</span>; |
| <span class="kw">if </span>delta == <span class="number">0 </span>{ |
| <span class="kw">return </span><span class="prelude-val">Err</span>(()); <span class="comment">// Overflow |
| </span>} |
| } |
| <span class="kw">if </span>c == code_point { |
| <span class="comment">// Represent delta as a generalized variable-length integer: |
| </span><span class="kw">let </span><span class="kw-2">mut </span>q = delta; |
| <span class="kw">let </span><span class="kw-2">mut </span>k = BASE; |
| <span class="kw">loop </span>{ |
| <span class="kw">let </span>t = <span class="kw">if </span>k <= bias { |
| T_MIN |
| } <span class="kw">else if </span>k >= bias + T_MAX { |
| T_MAX |
| } <span class="kw">else </span>{ |
| k - bias |
| }; |
| <span class="kw">if </span>q < t { |
| <span class="kw">break</span>; |
| } |
| <span class="kw">let </span>value = t + ((q - t) % (BASE - t)); |
| output.push(value_to_digit(value)); |
| q = (q - t) / (BASE - t); |
| k += BASE; |
| } |
| output.push(value_to_digit(q)); |
| bias = adapt(delta, processed + <span class="number">1</span>, processed == basic_length); |
| delta = <span class="number">0</span>; |
| processed += <span class="number">1</span>; |
| } |
| } |
| delta += <span class="number">1</span>; |
| code_point += <span class="number">1</span>; |
| } |
| <span class="prelude-val">Ok</span>(()) |
| } |
| |
| <span class="attribute">#[inline] |
| </span><span class="kw">fn </span>value_to_digit(value: u32) -> char { |
| <span class="kw">match </span>value { |
| <span class="number">0</span>..=<span class="number">25 </span>=> (value <span class="kw">as </span>u8 + <span class="string">b'a'</span>) <span class="kw">as </span>char, <span class="comment">// a..z |
| </span><span class="number">26</span>..=<span class="number">35 </span>=> (value <span class="kw">as </span>u8 - <span class="number">26 </span>+ <span class="string">b'0'</span>) <span class="kw">as </span>char, <span class="comment">// 0..9 |
| </span><span class="kw">_ </span>=> <span class="macro">panic!</span>(), |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="idna" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
