vendor/combine/src/parser/byte.rs - toolchain/rustc - Git at Google

 //! Module containing parsers specialized on byte streams.

 use crate::{
     error::{self, ParseError, ParseResult::*},
     parser::{
         combinator::no_partial,
         range::{take_fn, TakeRange},
         repeat::skip_many,
         token::{satisfy, token, tokens_cmp, Token},
     },
     stream::{RangeStream, Stream},
     Parser,
 };

 /// Parses a byte and succeeds if the byte is equal to `c`.
 ///
 /// ```
 /// use combine::Parser;
 /// use combine::parser::byte::byte;
 /// assert_eq!(byte(b'!').parse(&b"!"[..]), Ok((b'!', &b""[..])));
 /// assert!(byte(b'A').parse(&b""[..]).is_err());
 /// assert!(byte(b'A').parse(&b"!"[..]).is_err());
 /// ```
 pub fn byte<Input>(c: u8) -> Token<Input>
 where
     Input: Stream<Token = u8>,
     Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
 {
     token(c)
 }

 macro_rules! byte_parser {
     ($name:ident, $ty:ident, $f: ident) => {{
         satisfy(|c: u8| c.$f())
             .expected(stringify!($name))
     }};
     ($name:ident, $ty:ident, $f: ident $($args:tt)+) => {{
         satisfy(|c: u8| c.$f $($args)+)
             .expected(stringify!($name))
     }};
 }

 /// Parses a base-10 digit (0–9).
 ///
 /// ```
 /// use combine::Parser;
 /// use combine::parser::byte::digit;
 /// assert_eq!(digit().parse(&b"9"[..]), Ok((b'9', &b""[..])));
 /// assert!(digit().parse(&b"A"[..]).is_err());
 /// ```
 pub fn digit<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
 where
     Input: Stream<Token = u8>,
     Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
 {
     byte_parser!(digit, Digit, is_ascii_digit())
 }

 /// Parses a `b' '`, `b'\t'`, `b'\n'` or `'b\'r'`.
 ///
 /// ```
 /// use combine::Parser;
 /// use combine::parser::byte::space;
 /// assert_eq!(space().parse(&b" "[..]), Ok((b' ', &b""[..])));
 /// assert_eq!(space().parse(&b"  "[..]), Ok((b' ', &b" "[..])));
 /// assert!(space().parse(&b"!"[..]).is_err());
 /// assert!(space().parse(&b""[..]).is_err());
 /// ```
 pub fn space<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
 where
     Input: Stream<Token = u8>,
     Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
 {
     byte_parser!(space, Space, is_ascii_whitespace)
 }

 /// Skips over [`space`] zero or more times
 ///
 /// [`space`]: fn.space.html
 ///
 /// ```
 /// use combine::Parser;
 /// use combine::parser::byte::spaces;
 /// assert_eq!(spaces().parse(&b""[..]), Ok(((), &b""[..])));
 /// assert_eq!(spaces().parse(&b"   "[..]), Ok(((), &b""[..])));
 /// ```
 pub fn spaces<Input>() -> impl Parser<Input, Output = ()>
 where
     Input: Stream<Token = u8>,
     Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
 {
     skip_many(space()).expected("whitespaces")
 }

 /// Parses a newline byte (`b'\n'`).
 ///
 /// ```
 /// use combine::Parser;
 /// use combine::parser::byte::newline;
 /// assert_eq!(newline().parse(&b"\n"[..]), Ok((b'\n', &b""[..])));
 /// assert!(newline().parse(&b"\r"[..]).is_err());
 /// ```
 pub fn newline<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
 where
     Input: Stream<Token = u8>,
     Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
 {
     satisfy(|ch: u8| ch == b'\n').expected("lf newline")
 }

 /// Parses carriage return and newline (`&b"\r\n"`), returning the newline byte.
 ///
 /// ```
 /// use combine::Parser;
 /// use combine::parser::byte::crlf;
 /// assert_eq!(crlf().parse(&b"\r\n"[..]), Ok((b'\n', &b""[..])));
 /// assert!(crlf().parse(&b"\r"[..]).is_err());
 /// assert!(crlf().parse(&b"\n"[..]).is_err());
 /// ```
 pub fn crlf<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
 where
     Input: Stream<Token = u8>,
     Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
 {
     no_partial(satisfy(|ch: u8| ch == b'\r').with(newline())).expected("crlf newline")
 }

 /// Parses a tab byte (`b'\t'`).
 ///
 /// ```
 /// use combine::Parser;
 /// use combine::parser::byte::tab;
 /// assert_eq!(tab().parse(&b"\t"[..]), Ok((b'\t', &b""[..])));
 /// assert!(tab().parse(&b" "[..]).is_err());
 /// ```
 pub fn tab<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
 where
     Input: Stream<Token = u8>,
     Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
 {
     satisfy(|ch| ch == b'\t').expected("tab")
 }

 /// Parses an uppercase ASCII letter (A–Z).
 ///
 /// ```
 /// use combine::Parser;
 /// use combine::parser::byte::upper;
 /// assert_eq!(upper().parse(&b"A"[..]), Ok((b'A', &b""[..])));
 /// assert!(upper().parse(&b"a"[..]).is_err());
 /// ```
 pub fn upper<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
 where
     Input: Stream<Token = u8>,
     Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
 {
     byte_parser!(upper, Upper, is_ascii_uppercase)
 }

 /// Parses an lowercase ASCII letter (a–z).
 ///
 /// ```
 /// use combine::Parser;
 /// use combine::parser::byte::lower;
 /// assert_eq!(lower().parse(&b"a"[..]), Ok((b'a', &b""[..])));
 /// assert!(lower().parse(&b"A"[..]).is_err());
 /// ```
 pub fn lower<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
 where
     Input: Stream<Token = u8>,
     Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
 {
     byte_parser!(lower, Lower, is_ascii_lowercase)
 }

 /// Parses either an ASCII alphabet letter or digit (a–z, A–Z, 0–9).
 ///
 /// ```
 /// use combine::Parser;
 /// use combine::parser::byte::alpha_num;
 /// assert_eq!(alpha_num().parse(&b"A"[..]), Ok((b'A', &b""[..])));
 /// assert_eq!(alpha_num().parse(&b"1"[..]), Ok((b'1', &b""[..])));
 /// assert!(alpha_num().parse(&b"!"[..]).is_err());
 /// ```
 pub fn alpha_num<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
 where
     Input: Stream<Token = u8>,
     Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
 {
     byte_parser!(alpha_num, AlphaNum, is_ascii_alphanumeric)
 }

 /// Parses an ASCII alphabet letter (a–z, A–Z).
 ///
 /// ```
 /// use combine::Parser;
 /// use combine::parser::byte::letter;
 /// assert_eq!(letter().parse(&b"a"[..]), Ok((b'a', &b""[..])));
 /// assert_eq!(letter().parse(&b"A"[..]), Ok((b'A', &b""[..])));
 /// assert!(letter().parse(&b"9"[..]).is_err());
 /// ```
 pub fn letter<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
 where
     Input: Stream<Token = u8>,
     Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
 {
     byte_parser!(letter, Letter, is_ascii_alphabetic)
 }

 /// Parses an octal digit.
 ///
 /// ```
 /// use combine::Parser;
 /// use combine::parser::byte::oct_digit;
 /// assert_eq!(oct_digit().parse(&b"7"[..]), Ok((b'7', &b""[..])));
 /// assert!(oct_digit().parse(&b"8"[..]).is_err());
 /// ```
 pub fn oct_digit<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
 where
     Input: Stream<Token = u8>,
     Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
 {
     satisfy(|ch| (b'0'..=b'7').contains(&ch)).expected("octal digit")
 }

 /// Parses an ASCII hexdecimal digit (accepts both uppercase and lowercase).
 ///
 /// ```
 /// use combine::Parser;
 /// use combine::parser::byte::hex_digit;
 /// assert_eq!(hex_digit().parse(&b"F"[..]), Ok((b'F', &b""[..])));
 /// assert!(hex_digit().parse(&b"H"[..]).is_err());
 /// ```
 pub fn hex_digit<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
 where
     Input: Stream<Token = u8>,
     Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
 {
     byte_parser!(hex_digit, HexDigit, is_ascii_hexdigit())
 }

 parser! {
 /// Parses the bytes `s`.
 ///
 /// If you have a stream implementing [`RangeStream`] such as `&[u8]` you can also use the
 /// [`range`] parser which may be more efficient.
 ///
 /// ```
 /// # extern crate combine;
 /// # use combine::*;
 /// # use combine::parser::byte::bytes;
 /// # fn main() {
 /// let result = bytes(&b"rust"[..])
 ///     .parse(&b"rust"[..])
 ///     .map(|x| x.0);
 /// assert_eq!(result, Ok(&b"rust"[..]));
 /// # }
 /// ```
 ///
 /// [`RangeStream`]: super::super::stream::RangeStream
 /// [`range`]: super::range::range
 pub fn bytes['a, 'b, Input](s: &'static [u8])(Input) -> &'a [u8]
 where [
     Input: Stream<Token = u8, Range = &'b [u8]>,
     Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
 ]
 {
     bytes_cmp(s, |l: u8, r: u8| l == r)
 }
 }

 parser! {
 /// Parses the bytes `s` using `cmp` to compare each token.
 ///
 /// If you have a stream implementing [`RangeStream`] such as `&[u8]` you can also use the
 /// [`range`] parser which may be more efficient.
 ///
 /// ```
 /// # extern crate combine;
 /// # use combine::*;
 /// # use combine::parser::byte::bytes_cmp;
 /// # use combine::stream::easy::Info;
 /// # fn main() {
 /// let result = bytes_cmp(&b"abc"[..], |l, r| l.eq_ignore_ascii_case(&r))
 ///     .parse(&b"AbC"[..]);
 /// assert_eq!(result, Ok((&b"abc"[..], &b""[..])));
 /// # }
 /// ```
 ///
 /// [`RangeStream`]: super::super::stream::RangeStream
 /// [`range`]: super::range::range
 pub fn bytes_cmp['a, 'b, C, Input](s: &'static [u8], cmp: C)(Input) -> &'a [u8]
 where [
     C: FnMut(u8, u8) -> bool,
     Input: Stream<Token = u8, Range = &'b [u8]>,
     Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
 ]
 {
     let s = *s;
     tokens_cmp(s.iter().cloned(), cmp)
         .map(move |_| s)
         .expected(error::Range(s))
 }
 }

 macro_rules! take_until {
     (
         $(#[$attr:meta])*
         $type_name: ident, $func_name: ident, $memchr: ident, $($param: ident),+
     ) => {
         parser!{
             #[derive(Clone)]
             pub struct $type_name;
             type PartialState = usize;
             $(#[$attr])*
             pub fn $func_name[Input]($($param : u8),*)(Input) -> Input::Range
                 where [
                     Input: RangeStream,
                     Input::Range: AsRef<[u8]> + crate::stream::Range,
                 ]
             {
                 take_fn(move |haystack: Input::Range| {
                     let haystack = haystack.as_ref();
                     match ::memchr::$memchr( $(*$param),+ , haystack) {
                         Some(i) => TakeRange::Found(i),
                         None => TakeRange::NotFound(haystack.len()),
                     }
                 })
             }
         }
     }
 }

 take_until! {
     /// Zero-copy parser which reads a range of 0 or more tokens until `a` is found.
     ///
     /// If `a` is not found, the parser will return an error.
     ///
     /// ```
     /// # extern crate combine;
     /// # use combine::parser::byte::take_until_byte;
     /// # use combine::*;
     /// # fn main() {
     /// let mut parser = take_until_byte(b'\r');
     /// let result = parser.parse("To: user@example.com\r\n");
     /// assert_eq!(result, Ok(("To: user@example.com", "\r\n")));
     /// let result = parser.parse("Hello, world\n");
     /// assert!(result.is_err());
     /// # }
     /// ```
     TakeUntilByte, take_until_byte, memchr, a
 }
 take_until! {
     /// Zero-copy parser which reads a range of 0 or more tokens until `a` or `b` is found.
     ///
     /// If `a` or `b` is not found, the parser will return an error.
     ///
     /// ```
     /// # extern crate combine;
     /// # use combine::parser::byte::take_until_byte2;
     /// # use combine::*;
     /// # fn main() {
     /// let mut parser = take_until_byte2(b'\r', b'\n');
     /// let result = parser.parse("To: user@example.com\r\n");
     /// assert_eq!(result, Ok(("To: user@example.com", "\r\n")));
     /// let result = parser.parse("Hello, world\n");
     /// assert_eq!(result, Ok(("Hello, world", "\n")));
     /// # }
     /// ```
     TakeUntilByte2, take_until_byte2, memchr2, a, b
 }
 take_until! {
     /// Zero-copy parser which reads a range of 0 or more tokens until `a`, 'b' or `c` is found.
     ///
     /// If `a`, 'b' or `c` is not found, the parser will return an error.
     ///
     /// ```
     /// # extern crate combine;
     /// # use combine::parser::byte::take_until_byte3;
     /// # use combine::*;
     /// # fn main() {
     /// let mut parser = take_until_byte3(b'\r', b'\n', b' ');
     /// let result = parser.parse("To: user@example.com\r\n");
     /// assert_eq!(result, Ok(("To:", " user@example.com\r\n")));
     /// let result = parser.parse("Helloworld");
     /// assert!(result.is_err());
     /// # }
     /// ```
     TakeUntilByte3, take_until_byte3, memchr3, a, b, c
 }

 parser! {
 type PartialState = usize;
 /// Zero-copy parser which reads a range of 0 or more tokens until `needle` is found.
 ///
 /// If `a`, 'b' or `c` is not found, the parser will return an error.
 ///
 /// Optimized variant of [`take_until_range`](../range/fn.take_until_range.html)
 ///
 /// ```
 /// use combine::*;
 /// use combine::parser::byte::take_until_bytes;
 /// assert_eq!(
 ///     take_until_bytes(&b"\r\n"[..]).easy_parse(&b"abc\r\n"[..]).map(|(x, _)| x),
 ///     Ok((&b"abc"[..]))
 /// );
 /// // Also works on strings as long as `needle` is UTF-8
 /// assert_eq!(
 ///     take_until_bytes("\r\n".as_bytes()).easy_parse("abc\r\n").map(|(x, _)| x),
 ///     Ok(("abc"))
 /// );
 /// ```
 pub fn take_until_bytes['a, Input](needle: &'a [u8])(Input) -> Input::Range
 where [
     Input: RangeStream,
     Input::Range: AsRef<[u8]> + crate::stream::Range,
 ]
 {
     take_fn(move |haystack: Input::Range| {
         let haystack = haystack.as_ref();
         match memslice(needle, haystack) {
             Some(i) => TakeRange::Found(i),
             None => TakeRange::NotFound(haystack.len().saturating_sub(needle.len() - 1)),
         }
     })
 }

 }

 fn memslice(needle: &[u8], haystack: &[u8]) -> Option<usize> {
     let (&prefix, suffix) = match needle.split_first() {
         Some(x) => x,
         None => return Some(0),
     };
     for i in memchr::memchr_iter(prefix, haystack) {
         if haystack[i + 1..].starts_with(suffix) {
             return Some(i);
         }
     }
     None
 }

 /// Parsers for decoding numbers in big-endian or little-endian order.
 pub mod num {

     use crate::{error::ResultExt, lib::mem::size_of, parser::function::parser, stream::uncons};

     use super::*;

     macro_rules! integer_parser {
         (
             $(#[$attr:meta])*
             pub $type_name: ident,
             $output_type: ident, $be_name: ident, $le_name: ident, $read_name: ident
         ) => {
             $(#[$attr])*
             pub fn $be_name<'a, Input>() -> impl Parser<Input, Output = $output_type, PartialState = ()>
             where
                 Input: Stream<Token = u8>,
                 Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
             {
                 parser(|input: &mut Input| {
                     let checkpoint = input.checkpoint();
                     let result = (|input: &mut Input| {
                         let mut buffer = [0u8; size_of::<$output_type>()];
                         for elem in &mut buffer[..] {
                             *elem = ctry!(uncons(input)).0;
                         }
                         CommitOk($output_type::from_be_bytes(buffer))
                     })(input);
                     if result.is_err() {
                         input.reset(checkpoint).committed().into_result()?;
                     }
                     result.into_result()
                 })
             }

             $(#[$attr])*
             pub fn $le_name<'a, Input>() -> impl Parser<Input, Output = $output_type, PartialState = ()>
             where
                 Input: Stream<Token = u8>,
                 Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
             {
                 parser(|input: &mut Input| {
                     let checkpoint = input.checkpoint();
                     let result = (|input: &mut Input| {
                         let mut buffer = [0u8; size_of::<$output_type>()];
                         for elem in &mut buffer[..] {
                             *elem = ctry!(uncons(input)).0;
                         }
                         CommitOk($output_type::from_le_bytes(buffer))
                     })(input);
                     if result.is_err() {
                         input.reset(checkpoint).committed().into_result()?;
                     }
                     result.into_result()
                 })
             }
         }
     }

     integer_parser!(
         /// Reads a u16 out of the byte stream with the specified endianess
         ///
         /// ```
         /// use combine::Parser;
         /// use combine::parser::byte::num::le_u16;
         ///
         /// assert_eq!(le_u16().parse(&b"\x01\0"[..]), Ok((1, &b""[..])));
         /// assert!(le_u16().parse(&b"\0"[..]).is_err());
         /// ```
         pub U16, u16, be_u16, le_u16, read_u16
     );
     integer_parser!(
         /// Reads a u32 out of the byte stream with the specified endianess
         ///
         /// ```
         /// use combine::Parser;
         /// use combine::parser::byte::num::le_u32;
         ///
         /// assert_eq!(le_u32().parse(&b"\x01\0\0\0"[..]), Ok((1, &b""[..])));
         /// assert!(le_u32().parse(&b"\x01\0\0"[..]).is_err());
         /// ```
         pub U32, u32, be_u32, le_u32, read_u32
     );
     integer_parser!(
         /// Reads a u64 out of the byte stream with the specified endianess
         ///
         /// ```
         /// use combine::Parser;
         /// use combine::parser::byte::num::le_u64;
         ///
         /// assert_eq!(le_u64().parse(&b"\x01\0\0\0\0\0\0\0"[..]), Ok((1, &b""[..])));
         /// assert!(le_u64().parse(&b"\x01\0\0\0\0\0\0"[..]).is_err());
         /// ```
         pub U64, u64, be_u64, le_u64, read_u64
     );

     integer_parser!(
         /// Reads a i16 out of the byte stream with the specified endianess
         ///
         /// ```
         /// use combine::Parser;
         /// use combine::parser::byte::num::le_i16;
         ///
         /// assert_eq!(le_i16().parse(&b"\x01\0"[..]), Ok((1, &b""[..])));
         /// assert!(le_i16().parse(&b"\x01"[..]).is_err());
         /// ```
         pub I16, i16, be_i16, le_i16, read_i16
     );

     integer_parser!(
         /// Reads a i32 out of the byte stream with the specified endianess
         ///
         /// ```
         /// use combine::Parser;
         /// use combine::parser::byte::num::le_i32;
         ///
         /// assert_eq!(le_i32().parse(&b"\x01\0\0\0"[..]), Ok((1, &b""[..])));
         /// assert!(le_i32().parse(&b"\x01\0\0"[..]).is_err());
         /// ```
         pub I32, i32, be_i32, le_i32, read_i32
     );
     integer_parser!(
         /// Reads a i64 out of the byte stream with the specified endianess
         ///
         /// ```
         /// use combine::Parser;
         /// use combine::parser::byte::num::le_i64;
         ///
         /// assert_eq!(le_i64().parse(&b"\x01\0\0\0\0\0\0\0"[..]), Ok((1, &b""[..])));
         /// assert!(le_i64().parse(&b"\x01\0\0\0\0\0\0"[..]).is_err());
         /// ```
         pub I64, i64, be_i64, le_i64, read_i64
     );

     integer_parser!(
         /// Reads a i32 out of the byte stream with the specified endianess
         ///
         /// ```
         /// use combine::Parser;
         /// use combine::parser::byte::num::le_f32;
         ///
         /// let buf = 123.45f32.to_le_bytes();
         /// assert_eq!(le_f32().parse(&buf[..]), Ok((123.45, &b""[..])));
         /// assert!(le_f32().parse(&b"\x01\0\0"[..]).is_err());
         /// ```
         pub F32, f32, be_f32, le_f32, read_f32
     );
     integer_parser!(
         /// Reads a i64 out of the byte stream with the specified endianess
         ///
         /// ```
         /// use combine::Parser;
         /// use combine::parser::byte::num::le_f64;
         ///
         /// let buf = 123.45f64.to_le_bytes();
         /// assert_eq!(le_f64().parse(&buf[..]), Ok((123.45, &b""[..])));
         /// assert!(le_f64().parse(&b"\x01\0\0\0\0\0\0"[..]).is_err());
         /// ```
         pub F64, f64, be_f64, le_f64, read_f64
     );

     #[cfg(all(feature = "std", test))]
     mod tests {

         use crate::stream::{buffered, position, IteratorStream};

         use super::*;

         #[test]
         fn no_rangestream() {
             let buf = 123.45f64.to_le_bytes();
             assert_eq!(
                 le_f64()
                     .parse(buffered::Stream::new(
                         position::Stream::new(IteratorStream::new(buf.iter().cloned())),
                         1
                     ))
                     .map(|(t, _)| t),
                 Ok(123.45)
             );
             assert_eq!(
                 le_f64()
                     .parse(buffered::Stream::new(
                         position::Stream::new(IteratorStream::new(buf.iter().cloned())),
                         1
                     ))
                     .map(|(t, _)| t),
                 Ok(123.45)
             );
             let buf = 123.45f64.to_be_bytes();
             assert_eq!(
                 be_f64()
                     .parse(buffered::Stream::new(
                         position::Stream::new(IteratorStream::new(buf.iter().cloned())),
                         1
                     ))
                     .map(|(t, _)| t),
                 Ok(123.45)
             );
         }
     }
 }

 #[cfg(all(feature = "std", test))]
 mod tests {

     use crate::stream::{buffered, position, read};

     use super::*;

     #[test]
     fn memslice_basic() {
         let haystack = b"abc123";
         assert_eq!(memslice(b"", haystack), Some(0));
         assert_eq!(memslice(b"a", haystack), Some(0));
         assert_eq!(memslice(b"ab", haystack), Some(0));
         assert_eq!(memslice(b"c12", haystack), Some(2));

         let haystack2 = b"abcab2";
         assert_eq!(memslice(b"abc", haystack2), Some(0));
         assert_eq!(memslice(b"ab2", haystack2), Some(3));

         let haystack3 = b"aaabaaaa";
         assert_eq!(memslice(b"aaaa", haystack3), Some(4));
     }

     #[test]
     fn bytes_read_stream() {
         assert!(bytes(b"abc")
             .parse(buffered::Stream::new(
                 position::Stream::new(read::Stream::new("abc".as_bytes())),
                 1
             ))
             .is_ok());
     }
 }
	//! Module containing parsers specialized on byte streams.

	use crate::{
	error::{self, ParseError, ParseResult::*},
	parser::{
	combinator::no_partial,
	range::{take_fn, TakeRange},
	repeat::skip_many,
	token::{satisfy, token, tokens_cmp, Token},
	},
	stream::{RangeStream, Stream},
	Parser,
	};

	/// Parses a byte and succeeds if the byte is equal to `c`.
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::byte;
	/// assert_eq!(byte(b'!').parse(&b"!"[..]), Ok((b'!', &b""[..])));
	/// assert!(byte(b'A').parse(&b""[..]).is_err());
	/// assert!(byte(b'A').parse(&b"!"[..]).is_err());
	/// ```
	pub fn byte<Input>(c: u8) -> Token<Input>
	where
	Input: Stream<Token = u8>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	{
	token(c)
	}

	macro_rules! byte_parser {
	($name:ident, $ty:ident, $f: ident) => {{
	satisfy(\|c: u8\| c.$f())
	.expected(stringify!($name))
	}};
	($name:ident, $ty:ident, $f: ident $($args:tt)+) => {{
	satisfy(\|c: u8\| c.$f $($args)+)
	.expected(stringify!($name))
	}};
	}

	/// Parses a base-10 digit (0–9).
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::digit;
	/// assert_eq!(digit().parse(&b"9"[..]), Ok((b'9', &b""[..])));
	/// assert!(digit().parse(&b"A"[..]).is_err());
	/// ```
	pub fn digit<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
	where
	Input: Stream<Token = u8>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	{
	byte_parser!(digit, Digit, is_ascii_digit())
	}

	/// Parses a `b' '`, `b'\t'`, `b'\n'` or `'b\'r'`.
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::space;
	/// assert_eq!(space().parse(&b" "[..]), Ok((b' ', &b""[..])));
	/// assert_eq!(space().parse(&b" "[..]), Ok((b' ', &b" "[..])));
	/// assert!(space().parse(&b"!"[..]).is_err());
	/// assert!(space().parse(&b""[..]).is_err());
	/// ```
	pub fn space<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
	where
	Input: Stream<Token = u8>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	{
	byte_parser!(space, Space, is_ascii_whitespace)
	}

	/// Skips over [`space`] zero or more times
	///
	/// [`space`]: fn.space.html
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::spaces;
	/// assert_eq!(spaces().parse(&b""[..]), Ok(((), &b""[..])));
	/// assert_eq!(spaces().parse(&b" "[..]), Ok(((), &b""[..])));
	/// ```
	pub fn spaces<Input>() -> impl Parser<Input, Output = ()>
	where
	Input: Stream<Token = u8>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	{
	skip_many(space()).expected("whitespaces")
	}

	/// Parses a newline byte (`b'\n'`).
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::newline;
	/// assert_eq!(newline().parse(&b"\n"[..]), Ok((b'\n', &b""[..])));
	/// assert!(newline().parse(&b"\r"[..]).is_err());
	/// ```
	pub fn newline<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
	where
	Input: Stream<Token = u8>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	{
	satisfy(\|ch: u8\| ch == b'\n').expected("lf newline")
	}

	/// Parses carriage return and newline (`&b"\r\n"`), returning the newline byte.
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::crlf;
	/// assert_eq!(crlf().parse(&b"\r\n"[..]), Ok((b'\n', &b""[..])));
	/// assert!(crlf().parse(&b"\r"[..]).is_err());
	/// assert!(crlf().parse(&b"\n"[..]).is_err());
	/// ```
	pub fn crlf<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
	where
	Input: Stream<Token = u8>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	{
	no_partial(satisfy(\|ch: u8\| ch == b'\r').with(newline())).expected("crlf newline")
	}

	/// Parses a tab byte (`b'\t'`).
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::tab;
	/// assert_eq!(tab().parse(&b"\t"[..]), Ok((b'\t', &b""[..])));
	/// assert!(tab().parse(&b" "[..]).is_err());
	/// ```
	pub fn tab<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
	where
	Input: Stream<Token = u8>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	{
	satisfy(\|ch\| ch == b'\t').expected("tab")
	}

	/// Parses an uppercase ASCII letter (A–Z).
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::upper;
	/// assert_eq!(upper().parse(&b"A"[..]), Ok((b'A', &b""[..])));
	/// assert!(upper().parse(&b"a"[..]).is_err());
	/// ```
	pub fn upper<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
	where
	Input: Stream<Token = u8>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	{
	byte_parser!(upper, Upper, is_ascii_uppercase)
	}

	/// Parses an lowercase ASCII letter (a–z).
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::lower;
	/// assert_eq!(lower().parse(&b"a"[..]), Ok((b'a', &b""[..])));
	/// assert!(lower().parse(&b"A"[..]).is_err());
	/// ```
	pub fn lower<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
	where
	Input: Stream<Token = u8>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	{
	byte_parser!(lower, Lower, is_ascii_lowercase)
	}

	/// Parses either an ASCII alphabet letter or digit (a–z, A–Z, 0–9).
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::alpha_num;
	/// assert_eq!(alpha_num().parse(&b"A"[..]), Ok((b'A', &b""[..])));
	/// assert_eq!(alpha_num().parse(&b"1"[..]), Ok((b'1', &b""[..])));
	/// assert!(alpha_num().parse(&b"!"[..]).is_err());
	/// ```
	pub fn alpha_num<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
	where
	Input: Stream<Token = u8>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	{
	byte_parser!(alpha_num, AlphaNum, is_ascii_alphanumeric)
	}

	/// Parses an ASCII alphabet letter (a–z, A–Z).
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::letter;
	/// assert_eq!(letter().parse(&b"a"[..]), Ok((b'a', &b""[..])));
	/// assert_eq!(letter().parse(&b"A"[..]), Ok((b'A', &b""[..])));
	/// assert!(letter().parse(&b"9"[..]).is_err());
	/// ```
	pub fn letter<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
	where
	Input: Stream<Token = u8>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	{
	byte_parser!(letter, Letter, is_ascii_alphabetic)
	}

	/// Parses an octal digit.
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::oct_digit;
	/// assert_eq!(oct_digit().parse(&b"7"[..]), Ok((b'7', &b""[..])));
	/// assert!(oct_digit().parse(&b"8"[..]).is_err());
	/// ```
	pub fn oct_digit<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
	where
	Input: Stream<Token = u8>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	{
	satisfy(\|ch\| (b'0'..=b'7').contains(&ch)).expected("octal digit")
	}

	/// Parses an ASCII hexdecimal digit (accepts both uppercase and lowercase).
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::hex_digit;
	/// assert_eq!(hex_digit().parse(&b"F"[..]), Ok((b'F', &b""[..])));
	/// assert!(hex_digit().parse(&b"H"[..]).is_err());
	/// ```
	pub fn hex_digit<Input>() -> impl Parser<Input, Output = u8, PartialState = ()>
	where
	Input: Stream<Token = u8>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	{
	byte_parser!(hex_digit, HexDigit, is_ascii_hexdigit())
	}

	parser! {
	/// Parses the bytes `s`.
	///
	/// If you have a stream implementing [`RangeStream`] such as `&[u8]` you can also use the
	/// [`range`] parser which may be more efficient.
	///
	/// ```
	/// # extern crate combine;
	/// # use combine::*;
	/// # use combine::parser::byte::bytes;
	/// # fn main() {
	/// let result = bytes(&b"rust"[..])
	/// .parse(&b"rust"[..])
	/// .map(\|x\| x.0);
	/// assert_eq!(result, Ok(&b"rust"[..]));
	/// # }
	/// ```
	///
	/// [`RangeStream`]: super::super::stream::RangeStream
	/// [`range`]: super::range::range
	pub fn bytes['a, 'b, Input](s: &'static [u8])(Input) -> &'a [u8]
	where [
	Input: Stream<Token = u8, Range = &'b [u8]>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	]
	{
	bytes_cmp(s, \|l: u8, r: u8\| l == r)
	}
	}

	parser! {
	/// Parses the bytes `s` using `cmp` to compare each token.
	///
	/// If you have a stream implementing [`RangeStream`] such as `&[u8]` you can also use the
	/// [`range`] parser which may be more efficient.
	///
	/// ```
	/// # extern crate combine;
	/// # use combine::*;
	/// # use combine::parser::byte::bytes_cmp;
	/// # use combine::stream::easy::Info;
	/// # fn main() {
	/// let result = bytes_cmp(&b"abc"[..], \|l, r\| l.eq_ignore_ascii_case(&r))
	/// .parse(&b"AbC"[..]);
	/// assert_eq!(result, Ok((&b"abc"[..], &b""[..])));
	/// # }
	/// ```
	///
	/// [`RangeStream`]: super::super::stream::RangeStream
	/// [`range`]: super::range::range
	pub fn bytes_cmp['a, 'b, C, Input](s: &'static [u8], cmp: C)(Input) -> &'a [u8]
	where [
	C: FnMut(u8, u8) -> bool,
	Input: Stream<Token = u8, Range = &'b [u8]>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	]
	{
	let s = *s;
	tokens_cmp(s.iter().cloned(), cmp)
	.map(move \|_\| s)
	.expected(error::Range(s))
	}
	}

	macro_rules! take_until {
	(
	$(#[$attr:meta])*
	$type_name: ident, $func_name: ident, $memchr: ident, $($param: ident),+
	) => {
	parser!{
	#[derive(Clone)]
	pub struct $type_name;
	type PartialState = usize;
	$(#[$attr])*
	pub fn $func_name[Input]($($param : u8),*)(Input) -> Input::Range
	where [
	Input: RangeStream,
	Input::Range: AsRef<[u8]> + crate::stream::Range,
	]
	{
	take_fn(move \|haystack: Input::Range\| {
	let haystack = haystack.as_ref();
	match ::memchr::$memchr( $(*$param),+ , haystack) {
	Some(i) => TakeRange::Found(i),
	None => TakeRange::NotFound(haystack.len()),
	}
	})
	}
	}
	}
	}

	take_until! {
	/// Zero-copy parser which reads a range of 0 or more tokens until `a` is found.
	///
	/// If `a` is not found, the parser will return an error.
	///
	/// ```
	/// # extern crate combine;
	/// # use combine::parser::byte::take_until_byte;
	/// # use combine::*;
	/// # fn main() {
	/// let mut parser = take_until_byte(b'\r');
	/// let result = parser.parse("To: user@example.com\r\n");
	/// assert_eq!(result, Ok(("To: user@example.com", "\r\n")));
	/// let result = parser.parse("Hello, world\n");
	/// assert!(result.is_err());
	/// # }
	/// ```
	TakeUntilByte, take_until_byte, memchr, a
	}
	take_until! {
	/// Zero-copy parser which reads a range of 0 or more tokens until `a` or `b` is found.
	///
	/// If `a` or `b` is not found, the parser will return an error.
	///
	/// ```
	/// # extern crate combine;
	/// # use combine::parser::byte::take_until_byte2;
	/// # use combine::*;
	/// # fn main() {
	/// let mut parser = take_until_byte2(b'\r', b'\n');
	/// let result = parser.parse("To: user@example.com\r\n");
	/// assert_eq!(result, Ok(("To: user@example.com", "\r\n")));
	/// let result = parser.parse("Hello, world\n");
	/// assert_eq!(result, Ok(("Hello, world", "\n")));
	/// # }
	/// ```
	TakeUntilByte2, take_until_byte2, memchr2, a, b
	}
	take_until! {
	/// Zero-copy parser which reads a range of 0 or more tokens until `a`, 'b' or `c` is found.
	///
	/// If `a`, 'b' or `c` is not found, the parser will return an error.
	///
	/// ```
	/// # extern crate combine;
	/// # use combine::parser::byte::take_until_byte3;
	/// # use combine::*;
	/// # fn main() {
	/// let mut parser = take_until_byte3(b'\r', b'\n', b' ');
	/// let result = parser.parse("To: user@example.com\r\n");
	/// assert_eq!(result, Ok(("To:", " user@example.com\r\n")));
	/// let result = parser.parse("Helloworld");
	/// assert!(result.is_err());
	/// # }
	/// ```
	TakeUntilByte3, take_until_byte3, memchr3, a, b, c
	}

	parser! {
	type PartialState = usize;
	/// Zero-copy parser which reads a range of 0 or more tokens until `needle` is found.
	///
	/// If `a`, 'b' or `c` is not found, the parser will return an error.
	///
	/// Optimized variant of [`take_until_range`](../range/fn.take_until_range.html)
	///
	/// ```
	/// use combine::*;
	/// use combine::parser::byte::take_until_bytes;
	/// assert_eq!(
	/// take_until_bytes(&b"\r\n"[..]).easy_parse(&b"abc\r\n"[..]).map(\|(x, _)\| x),
	/// Ok((&b"abc"[..]))
	/// );
	/// // Also works on strings as long as `needle` is UTF-8
	/// assert_eq!(
	/// take_until_bytes("\r\n".as_bytes()).easy_parse("abc\r\n").map(\|(x, _)\| x),
	/// Ok(("abc"))
	/// );
	/// ```
	pub fn take_until_bytes['a, Input](needle: &'a [u8])(Input) -> Input::Range
	where [
	Input: RangeStream,
	Input::Range: AsRef<[u8]> + crate::stream::Range,
	]
	{
	take_fn(move \|haystack: Input::Range\| {
	let haystack = haystack.as_ref();
	match memslice(needle, haystack) {
	Some(i) => TakeRange::Found(i),
	None => TakeRange::NotFound(haystack.len().saturating_sub(needle.len() - 1)),
	}
	})
	}

	}

	fn memslice(needle: &[u8], haystack: &[u8]) -> Option<usize> {
	let (&prefix, suffix) = match needle.split_first() {
	Some(x) => x,
	None => return Some(0),
	};
	for i in memchr::memchr_iter(prefix, haystack) {
	if haystack[i + 1..].starts_with(suffix) {
	return Some(i);
	}
	}
	None
	}

	/// Parsers for decoding numbers in big-endian or little-endian order.
	pub mod num {

	use crate::{error::ResultExt, lib::mem::size_of, parser::function::parser, stream::uncons};

	use super::*;

	macro_rules! integer_parser {
	(
	$(#[$attr:meta])*
	pub $type_name: ident,
	$output_type: ident, $be_name: ident, $le_name: ident, $read_name: ident
	) => {
	$(#[$attr])*
	pub fn $be_name<'a, Input>() -> impl Parser<Input, Output = $output_type, PartialState = ()>
	where
	Input: Stream<Token = u8>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	{
	parser(\|input: &mut Input\| {
	let checkpoint = input.checkpoint();
	let result = (\|input: &mut Input\| {
	let mut buffer = [0u8; size_of::<$output_type>()];
	for elem in &mut buffer[..] {
	*elem = ctry!(uncons(input)).0;
	}
	CommitOk($output_type::from_be_bytes(buffer))
	})(input);
	if result.is_err() {
	input.reset(checkpoint).committed().into_result()?;
	}
	result.into_result()
	})
	}

	$(#[$attr])*
	pub fn $le_name<'a, Input>() -> impl Parser<Input, Output = $output_type, PartialState = ()>
	where
	Input: Stream<Token = u8>,
	Input::Error: ParseError<Input::Token, Input::Range, Input::Position>,
	{
	parser(\|input: &mut Input\| {
	let checkpoint = input.checkpoint();
	let result = (\|input: &mut Input\| {
	let mut buffer = [0u8; size_of::<$output_type>()];
	for elem in &mut buffer[..] {
	*elem = ctry!(uncons(input)).0;
	}
	CommitOk($output_type::from_le_bytes(buffer))
	})(input);
	if result.is_err() {
	input.reset(checkpoint).committed().into_result()?;
	}
	result.into_result()
	})
	}
	}
	}

	integer_parser!(
	/// Reads a u16 out of the byte stream with the specified endianess
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::num::le_u16;
	///
	/// assert_eq!(le_u16().parse(&b"\x01\0"[..]), Ok((1, &b""[..])));
	/// assert!(le_u16().parse(&b"\0"[..]).is_err());
	/// ```
	pub U16, u16, be_u16, le_u16, read_u16
	);
	integer_parser!(
	/// Reads a u32 out of the byte stream with the specified endianess
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::num::le_u32;
	///
	/// assert_eq!(le_u32().parse(&b"\x01\0\0\0"[..]), Ok((1, &b""[..])));
	/// assert!(le_u32().parse(&b"\x01\0\0"[..]).is_err());
	/// ```
	pub U32, u32, be_u32, le_u32, read_u32
	);
	integer_parser!(
	/// Reads a u64 out of the byte stream with the specified endianess
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::num::le_u64;
	///
	/// assert_eq!(le_u64().parse(&b"\x01\0\0\0\0\0\0\0"[..]), Ok((1, &b""[..])));
	/// assert!(le_u64().parse(&b"\x01\0\0\0\0\0\0"[..]).is_err());
	/// ```
	pub U64, u64, be_u64, le_u64, read_u64
	);

	integer_parser!(
	/// Reads a i16 out of the byte stream with the specified endianess
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::num::le_i16;
	///
	/// assert_eq!(le_i16().parse(&b"\x01\0"[..]), Ok((1, &b""[..])));
	/// assert!(le_i16().parse(&b"\x01"[..]).is_err());
	/// ```
	pub I16, i16, be_i16, le_i16, read_i16
	);

	integer_parser!(
	/// Reads a i32 out of the byte stream with the specified endianess
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::num::le_i32;
	///
	/// assert_eq!(le_i32().parse(&b"\x01\0\0\0"[..]), Ok((1, &b""[..])));
	/// assert!(le_i32().parse(&b"\x01\0\0"[..]).is_err());
	/// ```
	pub I32, i32, be_i32, le_i32, read_i32
	);
	integer_parser!(
	/// Reads a i64 out of the byte stream with the specified endianess
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::num::le_i64;
	///
	/// assert_eq!(le_i64().parse(&b"\x01\0\0\0\0\0\0\0"[..]), Ok((1, &b""[..])));
	/// assert!(le_i64().parse(&b"\x01\0\0\0\0\0\0"[..]).is_err());
	/// ```
	pub I64, i64, be_i64, le_i64, read_i64
	);

	integer_parser!(
	/// Reads a i32 out of the byte stream with the specified endianess
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::num::le_f32;
	///
	/// let buf = 123.45f32.to_le_bytes();
	/// assert_eq!(le_f32().parse(&buf[..]), Ok((123.45, &b""[..])));
	/// assert!(le_f32().parse(&b"\x01\0\0"[..]).is_err());
	/// ```
	pub F32, f32, be_f32, le_f32, read_f32
	);
	integer_parser!(
	/// Reads a i64 out of the byte stream with the specified endianess
	///
	/// ```
	/// use combine::Parser;
	/// use combine::parser::byte::num::le_f64;
	///
	/// let buf = 123.45f64.to_le_bytes();
	/// assert_eq!(le_f64().parse(&buf[..]), Ok((123.45, &b""[..])));
	/// assert!(le_f64().parse(&b"\x01\0\0\0\0\0\0"[..]).is_err());
	/// ```
	pub F64, f64, be_f64, le_f64, read_f64
	);

	#[cfg(all(feature = "std", test))]
	mod tests {

	use crate::stream::{buffered, position, IteratorStream};

	use super::*;

	#[test]
	fn no_rangestream() {
	let buf = 123.45f64.to_le_bytes();
	assert_eq!(
	le_f64()
	.parse(buffered::Stream::new(
	position::Stream::new(IteratorStream::new(buf.iter().cloned())),
	1
	))
	.map(\|(t, _)\| t),
	Ok(123.45)
	);
	assert_eq!(
	le_f64()
	.parse(buffered::Stream::new(
	position::Stream::new(IteratorStream::new(buf.iter().cloned())),
	1
	))
	.map(\|(t, _)\| t),
	Ok(123.45)
	);
	let buf = 123.45f64.to_be_bytes();
	assert_eq!(
	be_f64()
	.parse(buffered::Stream::new(
	position::Stream::new(IteratorStream::new(buf.iter().cloned())),
	1
	))
	.map(\|(t, _)\| t),
	Ok(123.45)
	);
	}
	}
	}

	#[cfg(all(feature = "std", test))]
	mod tests {

	use crate::stream::{buffered, position, read};

	use super::*;

	#[test]
	fn memslice_basic() {
	let haystack = b"abc123";
	assert_eq!(memslice(b"", haystack), Some(0));
	assert_eq!(memslice(b"a", haystack), Some(0));
	assert_eq!(memslice(b"ab", haystack), Some(0));
	assert_eq!(memslice(b"c12", haystack), Some(2));

	let haystack2 = b"abcab2";
	assert_eq!(memslice(b"abc", haystack2), Some(0));
	assert_eq!(memslice(b"ab2", haystack2), Some(3));

	let haystack3 = b"aaabaaaa";
	assert_eq!(memslice(b"aaaa", haystack3), Some(4));
	}

	#[test]
	fn bytes_read_stream() {
	assert!(bytes(b"abc")
	.parse(buffered::Stream::new(
	position::Stream::new(read::Stream::new("abc".as_bytes())),
	1
	))
	.is_ok());
	}
	}