use std::{
cmp,
convert::{TryFrom, TryInto},
fmt, str,
};
use derive_more::{Display, Error};
const MAX_QUALITY: u16 = 1000;
const MAX_FLOAT_QUALITY: f32 = 1.0;
#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
pub struct Quality(u16);
impl Quality {
fn from_f32(value: f32) -> Self {
debug_assert!(
(0.0f32..=1.0f32).contains(&value),
"q value must be between 0.0 and 1.0"
);
Quality((value * MAX_QUALITY as f32) as u16)
}
}
impl Default for Quality {
fn default() -> Quality {
Quality(MAX_QUALITY)
}
}
#[derive(Debug, Clone, Display, Error)]
pub struct QualityOutOfBounds;
impl TryFrom<u16> for Quality {
type Error = QualityOutOfBounds;
fn try_from(value: u16) -> Result<Self, Self::Error> {
if (0..=MAX_QUALITY).contains(&value) {
Ok(Quality(value))
} else {
Err(QualityOutOfBounds)
}
}
}
impl TryFrom<f32> for Quality {
type Error = QualityOutOfBounds;
fn try_from(value: f32) -> Result<Self, Self::Error> {
if (0.0..=MAX_FLOAT_QUALITY).contains(&value) {
Ok(Quality::from_f32(value))
} else {
Err(QualityOutOfBounds)
}
}
}
#[derive(Clone, PartialEq, Debug)]
pub struct QualityItem<T> {
pub item: T,
pub quality: Quality,
}
impl<T> QualityItem<T> {
pub fn new(item: T, quality: Quality) -> QualityItem<T> {
QualityItem { item, quality }
}
}
impl<T: PartialEq> cmp::PartialOrd for QualityItem<T> {
fn partial_cmp(&self, other: &QualityItem<T>) -> Option<cmp::Ordering> {
self.quality.partial_cmp(&other.quality)
}
}
impl<T: fmt::Display> fmt::Display for QualityItem<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Display::fmt(&self.item, f)?;
match self.quality.0 {
MAX_QUALITY => Ok(()),
0 => f.write_str("; q=0"),
x => write!(f, "; q=0.{}", format!("{:03}", x).trim_end_matches('0')),
}
}
}
impl<T: str::FromStr> str::FromStr for QualityItem<T> {
type Err = crate::error::ParseError;
fn from_str(qitem_str: &str) -> Result<QualityItem<T>, crate::error::ParseError> {
if !qitem_str.is_ascii() {
return Err(crate::error::ParseError::Header);
}
let mut raw_item = qitem_str;
let mut quality = 1f32;
let parts: Vec<_> = qitem_str.rsplitn(2, ';').map(str::trim).collect();
if parts.len() == 2 {
if parts[0].len() < 2 {
return Err(crate::error::ParseError::Header);
}
let start = &parts[0][0..2];
if start == "q=" || start == "Q=" {
let q_val = &parts[0][2..];
if q_val.len() > 5 {
return Err(crate::error::ParseError::Header);
}
let q_value = q_val
.parse::<f32>()
.map_err(|_| crate::error::ParseError::Header)?;
if (0f32..=1f32).contains(&q_value) {
quality = q_value;
raw_item = parts[1];
} else {
return Err(crate::error::ParseError::Header);
}
}
}
let item = raw_item
.parse::<T>()
.map_err(|_| crate::error::ParseError::Header)?;
Ok(QualityItem::new(item, Quality::from_f32(quality)))
}
}
pub fn qitem<T>(item: T) -> QualityItem<T> {
QualityItem::new(item, Quality::default())
}
pub fn q<T>(val: T) -> Quality
where
T: TryInto<Quality>,
T::Error: fmt::Debug,
{
val.try_into().unwrap()
}
#[cfg(test)]
mod tests {
use super::*;
#[derive(Clone, PartialEq, Debug)]
pub enum Encoding {
Chunked,
Brotli,
Gzip,
Deflate,
Compress,
Identity,
Trailers,
EncodingExt(String),
}
impl fmt::Display for Encoding {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
use Encoding::*;
f.write_str(match *self {
Chunked => "chunked",
Brotli => "br",
Gzip => "gzip",
Deflate => "deflate",
Compress => "compress",
Identity => "identity",
Trailers => "trailers",
EncodingExt(ref s) => s.as_ref(),
})
}
}
impl str::FromStr for Encoding {
type Err = crate::error::ParseError;
fn from_str(s: &str) -> Result<Encoding, crate::error::ParseError> {
use Encoding::*;
match s {
"chunked" => Ok(Chunked),
"br" => Ok(Brotli),
"deflate" => Ok(Deflate),
"gzip" => Ok(Gzip),
"compress" => Ok(Compress),
"identity" => Ok(Identity),
"trailers" => Ok(Trailers),
_ => Ok(EncodingExt(s.to_owned())),
}
}
}
#[test]
fn test_quality_item_fmt_q_1() {
use Encoding::*;
let x = qitem(Chunked);
assert_eq!(format!("{}", x), "chunked");
}
#[test]
fn test_quality_item_fmt_q_0001() {
use Encoding::*;
let x = QualityItem::new(Chunked, Quality(1));
assert_eq!(format!("{}", x), "chunked; q=0.001");
}
#[test]
fn test_quality_item_fmt_q_05() {
use Encoding::*;
let x = QualityItem {
item: EncodingExt("identity".to_owned()),
quality: Quality(500),
};
assert_eq!(format!("{}", x), "identity; q=0.5");
}
#[test]
fn test_quality_item_fmt_q_0() {
use Encoding::*;
let x = QualityItem {
item: EncodingExt("identity".to_owned()),
quality: Quality(0),
};
assert_eq!(x.to_string(), "identity; q=0");
}
#[test]
fn test_quality_item_from_str1() {
use Encoding::*;
let x: Result<QualityItem<Encoding>, _> = "chunked".parse();
assert_eq!(
x.unwrap(),
QualityItem {
item: Chunked,
quality: Quality(1000),
}
);
}
#[test]
fn test_quality_item_from_str2() {
use Encoding::*;
let x: Result<QualityItem<Encoding>, _> = "chunked; q=1".parse();
assert_eq!(
x.unwrap(),
QualityItem {
item: Chunked,
quality: Quality(1000),
}
);
}
#[test]
fn test_quality_item_from_str3() {
use Encoding::*;
let x: Result<QualityItem<Encoding>, _> = "gzip; q=0.5".parse();
assert_eq!(
x.unwrap(),
QualityItem {
item: Gzip,
quality: Quality(500),
}
);
}
#[test]
fn test_quality_item_from_str4() {
use Encoding::*;
let x: Result<QualityItem<Encoding>, _> = "gzip; q=0.273".parse();
assert_eq!(
x.unwrap(),
QualityItem {
item: Gzip,
quality: Quality(273),
}
);
}
#[test]
fn test_quality_item_from_str5() {
let x: Result<QualityItem<Encoding>, _> = "gzip; q=0.2739999".parse();
assert!(x.is_err());
}
#[test]
fn test_quality_item_from_str6() {
let x: Result<QualityItem<Encoding>, _> = "gzip; q=2".parse();
assert!(x.is_err());
}
#[test]
fn test_quality_item_ordering() {
let x: QualityItem<Encoding> = "gzip; q=0.5".parse().ok().unwrap();
let y: QualityItem<Encoding> = "gzip; q=0.273".parse().ok().unwrap();
let comparision_result: bool = x.gt(&y);
assert!(comparision_result)
}
#[test]
fn test_quality() {
assert_eq!(q(0.5), Quality(500));
}
#[test]
#[should_panic]
fn test_quality_invalid() {
q(-1.0);
}
#[test]
#[should_panic]
fn test_quality_invalid2() {
q(2.0);
}
#[test]
fn test_fuzzing_bugs() {
assert!("99999;".parse::<QualityItem<String>>().is_err());
assert!("\x0d;;;=\u{d6aa}==".parse::<QualityItem<String>>().is_err())
}
}