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//! Percent-encoded strings manipulation. //! //! This crate provides two types, [`PctStr`] and [`PctString`], similar to [`str`] and [`String`], //! representing percent-encoded strings used in URL, URI, IRI, etc. //! You can use them to encode, decode and compare percent-encoded strings. //! //! # Basic usage //! //! You can parse/decode percent-encoded strings by building a [`PctStr`] slice over a [`str`] slice. //! //! ``` //! use pct_str::PctStr; //! //! let pct_str = PctStr::new("Hello%20World%21").unwrap(); //! //! assert!(pct_str == "Hello World!"); //! //! let decoded_string: String = pct_str.decode(); //! println!("{}", decoded_string); // => Hello World! //! ``` //! //! To create new percent-encoded strings, use the [`PctString`] to copy or encode new strings. //! //! ``` //! use pct_str::{PctString, URIReserved}; //! //! // Copy the given percent-encoded string. //! let pct_string = PctString::new("Hello%20World%21").unwrap(); //! //! // Encode the given regular string. //! let pct_string = PctString::encode("Hello World!".chars(), URIReserved); //! //! println!("{}", pct_string.as_str()); // => Hello World%21 //! ``` //! //! You can choose which character will be percent-encoded by the `encode` function //! by implementing the [`Encoder`] trait. //! //! ``` //! use pct_str::{URIReserved, PctString}; //! //! struct CustomEncoder; //! //! impl pct_str::Encoder for CustomEncoder { //! fn encode(&self, c: char) -> bool { //! URIReserved.encode(c) || c.is_uppercase() //! } //! } //! //! let pct_string = PctString::encode("Hello World!".chars(), CustomEncoder); //! println!("{}", pct_string.as_str()); // => %48ello %57orld%21 //! ``` use std::hash; use std::fmt; use std::cmp::{PartialOrd, Ord, Ordering}; /// Encoding error. /// /// Raised when a given input string is not percent-encoded as expected. #[derive(Debug)] pub struct InvalidEncoding; /// Result of a function performing a percent-encoding check. pub type Result<T> = std::result::Result<T, InvalidEncoding>; /// Checks if a string is a correct percent-encoded string. pub fn is_pct_encoded(str: &str) -> bool { let mut chars = str.chars(); loop { match chars.next() { Some('%') => { match chars.next() { Some(c) if c.is_digit(16) => { match chars.next() { Some(c) if c.is_digit(16) => { break }, _ => return false } }, _ => return false } }, Some(_) => (), None => break } } true } /// Characters iterator. /// /// Iterates over the encoded characters of a percent-encoded string. pub struct Chars<'a> { inner: std::str::Chars<'a> } impl<'a> Iterator for Chars<'a> { type Item = char; fn next(&mut self) -> Option<char> { match self.inner.next() { Some('%') => { let a = self.inner.next().unwrap().to_digit(16).unwrap(); let b = self.inner.next().unwrap().to_digit(16).unwrap(); let codepoint = (a << 4 | b) as u32; Some(unsafe { std::char::from_u32_unchecked(codepoint) }) }, Some(c) => Some(c), None => None } } } impl<'a> std::iter::FusedIterator for Chars<'a> { } /// Percent-Encoded string slice. /// /// This is the equivalent of [`str`] for percent-encoded strings. /// This is an *unsized* type, meaning that it must always be used behind a /// pointer like `&` or [`Box`]. For an owned version of this type, /// see [`PctString`]. /// /// # Examples /// /// ``` /// use pct_str::PctStr; /// /// let buffer = "Hello%20World%21"; /// let pct_str = PctStr::new(buffer).unwrap(); /// /// // You can compare percent-encoded strings with a regular string. /// assert!(pct_str == "Hello World!"); /// /// // The underlying string is unchanged. /// assert!(pct_str.as_str() == "Hello%20World%21"); /// /// // Just as a regular string, you can iterate over the /// // encoded characters of `pct_str` with [`PctStr::chars`]. /// for c in pct_str.chars() { /// print!("{}", c); /// } /// /// // You can decode the string and every remove percent-encoded characters /// // with the [`PctStr::decode`] method. /// let decoded_string: String = pct_str.decode(); /// println!("{}", decoded_string); /// ``` pub struct PctStr { data: str } impl PctStr { /// Create a new percent-encoded string slice. /// /// The input slice is checked for correct percent-encoding. /// If the test fails, a [`InvalidEncoding`] error is returned. pub fn new<S: AsRef<str> + ?Sized>(str: &S) -> Result<&PctStr> { if is_pct_encoded(str.as_ref()) { Ok(unsafe { PctStr::new_unchecked(str) }) } else { Err(InvalidEncoding) } } /// Create a new percent-encoded string slice without checking for correct encoding. /// /// This is an unsafe function. The resulting string slice will have an undefined behaviour /// if the input slice is not percent-encoded. pub unsafe fn new_unchecked<S: AsRef<str> + ?Sized>(str: &S) -> &PctStr { &*(str.as_ref() as *const str as *const PctStr) } /// Length of the string slice, in bytes. /// /// Note that two percent-encoded strings with different lengths may /// represent the same string. #[inline] pub fn len(&self) -> usize { self.data.len() } /// Get the underlying percent-encoded string slice. #[inline] pub fn as_str(&self) -> &str { &self.data } /// Iterate over the encoded characters of the string. #[inline] pub fn chars(&self) -> Chars { Chars { inner: self.data.chars() } } /// Decoding. /// /// Return the string with the percent-encoded characters decoded. pub fn decode(&self) -> String { let mut decoded = String::with_capacity(self.len()); for c in self.chars() { decoded.push(c) } decoded } } impl PartialEq for PctStr { #[inline] fn eq(&self, other: &PctStr) -> bool { let mut a = self.chars(); let mut b = other.chars(); loop { match (a.next(), b.next()) { (Some(a), Some(b)) if a != b => return false, (Some(_), None) => return false, (None, Some(_)) => return false, (None, None) => break, _ => () } } true } } impl Eq for PctStr { } impl PartialEq<str> for PctStr { #[inline] fn eq(&self, other: &str) -> bool { let mut a = self.chars(); let mut b = other.chars(); loop { match (a.next(), b.next()) { (Some(a), Some(b)) if a != b => return false, (Some(_), None) => return false, (None, Some(_)) => return false, (None, None) => break, _ => () } } true } } impl PartialEq<PctString> for PctStr { #[inline] fn eq(&self, other: &PctString) -> bool { let mut a = self.chars(); let mut b = other.chars(); loop { match (a.next(), b.next()) { (Some(a), Some(b)) if a != b => return false, (Some(_), None) => return false, (None, Some(_)) => return false, (None, None) => break, _ => () } } true } } impl PartialOrd for PctStr { fn partial_cmp(&self, other: &PctStr) -> Option<Ordering> { Some(self.cmp(other)) } } impl Ord for PctStr { fn cmp(&self, other: &PctStr) -> Ordering { let mut self_chars = self.chars(); let mut other_chars = other.chars(); loop { match (self_chars.next(), other_chars.next()) { (None, None) => return Ordering::Equal, (None, Some(_)) => return Ordering::Less, (Some(_), None) => return Ordering::Greater, (Some(a), Some(b)) => { match a.cmp(&b) { Ordering::Less => return Ordering::Less, Ordering::Greater => return Ordering::Greater, Ordering::Equal => () } } } } } } impl PartialOrd<PctString> for PctStr { fn partial_cmp(&self, other: &PctString) -> Option<Ordering> { self.partial_cmp(other.as_pct_str()) } } impl hash::Hash for PctStr { #[inline] fn hash<H: hash::Hasher>(&self, hasher: &mut H) { for c in self.chars() { c.hash(hasher) } } } impl fmt::Display for PctStr { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { fmt::Display::fmt(&self.data, f) } } impl fmt::Debug for PctStr { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { fmt::Debug::fmt(&self.data, f) } } /// Encoding predicate. /// /// Instances of this trait are used along with the [`encode`](`PctString::encode`) function /// to decide which character must be percent-encoded. /// /// This crate provides a simple implementation of the trait, [`URIReserved`] /// encoding characters reserved in the URI syntax. /// /// # Example /// /// ``` /// use pct_str::{PctString, URIReserved}; /// /// let pct_string = PctString::encode("Hello World!".chars(), URIReserved); /// println!("{}", pct_string.as_str()); // => Hello World%21 /// ``` /// /// Custom encoder implementation: /// /// ``` /// use pct_str::{PctString, URIReserved}; /// /// struct CustomEncoder; /// /// impl pct_str::Encoder for CustomEncoder { /// fn encode(&self, c: char) -> bool { /// URIReserved.encode(c) || c.is_uppercase() /// } /// } /// /// let pct_string = PctString::encode("Hello World!".chars(), CustomEncoder); /// println!("{}", pct_string.as_str()); // => %48ello %57orld%21 /// ``` pub trait Encoder { /// Decide if the given character must be encoded. /// /// Note that the character `%` is always encoded even if this method returns `false` on it. /// Only characters with codepoint below `0x100` are encoded. fn encode(&self, c: char) -> bool; } /// Owned, mutable percent-encoded string. /// /// This is the equivalent of [`String`] for percent-encoded strings. /// It implements [`Deref`](`std::ops::Deref`) to [`PctStr`] meaning that all methods on [`PctStr`] slices are /// available on `PctString` values as well. pub struct PctString { data: String } unsafe fn to_hex_digit(b: u32) -> char { if b < 10 { std::char::from_u32_unchecked(b + 0x30) } else { std::char::from_u32_unchecked(b + 0x37) } } impl PctString { /// Create a new owned percent-encoded string. /// /// The input slice is checked for correct percent-encoding and copied. /// If the test fails, a [`InvalidEncoding`] error is returned. pub fn new<S: AsRef<str> + ?Sized>(str: &S) -> Result<PctString> { if is_pct_encoded(str.as_ref()) { Ok(PctString { data: str.as_ref().to_string() }) } else { Err(InvalidEncoding) } } /// Encode a string into a percent-encoded string. /// /// This function takes an [`Encoder`] instance to decide which character of the string must /// be encoded. /// /// # Example /// /// ``` /// use pct_str::{PctString, URIReserved}; /// /// let pct_string = PctString::encode("Hello World!".chars(), URIReserved); /// println!("{}", pct_string.as_str()); // => Hello World%21 /// ``` pub fn encode<I: Iterator<Item = char>, E: Encoder>(src: I, encoder: E) -> PctString { let mut encoded = String::new(); for c in src { let codepoint = c as u32; if c == '%' || (codepoint <= 0xff && encoder.encode(c)) { let a = (codepoint >> 4) & 0xf; let b = codepoint & 0xf; encoded.push('%'); unsafe { encoded.push(to_hex_digit(a)); encoded.push(to_hex_digit(b)); } } else { encoded.push(c); } } PctString { data: encoded } } /// Return this string as a borrowed percent-encoded string slice. #[inline] pub fn as_pct_str(&self) -> &PctStr { unsafe { PctStr::new_unchecked(&self.data) } } /// Return the internal string of the [`PctString`], consuming it #[inline] pub fn into_string(self) -> String { self.data } } impl std::ops::Deref for PctString { type Target = PctStr; #[inline] fn deref(&self) -> &PctStr { self.as_pct_str() } } impl PartialEq for PctString { #[inline] fn eq(&self, other: &PctString) -> bool { let mut a = self.chars(); let mut b = other.chars(); loop { match (a.next(), b.next()) { (Some(a), Some(b)) if a != b => return false, (Some(_), None) => return false, (None, Some(_)) => return false, (None, None) => break, _ => () } } true } } impl Eq for PctString { } impl PartialEq<PctStr> for PctString { #[inline] fn eq(&self, other: &PctStr) -> bool { let mut a = self.chars(); let mut b = other.chars(); loop { match (a.next(), b.next()) { (Some(a), Some(b)) if a != b => return false, (Some(_), None) => return false, (None, Some(_)) => return false, (None, None) => break, _ => () } } true } } impl PartialEq<&str> for PctString { #[inline] fn eq(&self, other: &&str) -> bool { let mut a = self.chars(); let mut b = other.chars(); loop { match (a.next(), b.next()) { (Some(a), Some(b)) if a != b => return false, (Some(_), None) => return false, (None, Some(_)) => return false, (None, None) => break, _ => () } } true } } impl PartialEq<str> for PctString { #[inline] fn eq(&self, other: &str) -> bool { self.eq(&other) } } impl PartialOrd for PctString { fn partial_cmp(&self, other: &PctString) -> Option<Ordering> { self.as_pct_str().partial_cmp(other.as_pct_str()) } } impl PartialOrd<PctStr> for PctString { fn partial_cmp(&self, other: &PctStr) -> Option<Ordering> { self.as_pct_str().partial_cmp(other) } } impl hash::Hash for PctString { #[inline] fn hash<H: hash::Hasher>(&self, hasher: &mut H) { for c in self.chars() { c.hash(hasher) } } } impl fmt::Display for PctString { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { fmt::Display::fmt(self.as_str(), f) } } impl fmt::Debug for PctString { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { fmt::Debug::fmt(self.as_str(), f) } } /// URI-reserved characters encoder. /// /// This [`Encoder`] encodes characters that are reserved in the syntax of URI according to /// [RFC 3986](https://tools.ietf.org/html/rfc3986). pub struct URIReserved; impl Encoder for URIReserved { fn encode(&self, c: char) -> bool { match c { '!' | '#' | '$' | '%' | '&' | '\'' | '(' | ')' | '*' | '+' | ',' | '/' | ':' | ';' | '=' | '?' | '@' | '[' | ']' => true, _ => false } } }