//! parsers recognizing numbers, complete input version

use crate::internal::*;
use crate::error::ParseError;
use crate::traits::{AsChar, InputIter, InputLength, InputTakeAtPosition};
use crate::lib::std::ops::{RangeFrom, RangeTo};
use crate::traits::{Offset, Slice};
use crate::error::{ErrorKind, make_error};
use crate::character::complete::{char, digit1};
use crate::combinator::{opt, cut, map, recognize};
use crate::branch::alt;
use crate::sequence::{tuple, pair};

/// Recognizes an unsigned 1 byte integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::be_u8;
///
/// let parser = |s| {
///   be_u8(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03abcefg"), Ok((&b"\x03abcefg"[..], 0x00)));
/// assert_eq!(parser(b""), Err(Err::Error((&[][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn be_u8<'a, E: ParseError<&'a[u8]>>(i: &'a[u8]) -> IResult<&'a[u8], u8, E> {
  if i.len() < 1 {
    Err(Err::Error(make_error(i, ErrorKind::Eof)))
  } else {
    Ok((&i[1..], i[0]))
  }
}

/// Recognizes a big endian unsigned 2 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::be_u16;
///
/// let parser = |s| {
///   be_u16(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03abcefg"), Ok((&b"abcefg"[..], 0x0003)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn be_u16<'a, E: ParseError<&'a[u8]>>(i: &'a[u8]) -> IResult<&'a[u8], u16, E> {
  if i.len() < 2 {
    Err(Err::Error(make_error(i, ErrorKind::Eof)))
  } else {
    let res = ((i[0] as u16) << 8) + i[1] as u16;
    Ok((&i[2..], res))
  }
}

/// Recognizes a big endian unsigned 3 byte integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::be_u24;
///
/// let parser = |s| {
///   be_u24(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03\x05abcefg"), Ok((&b"abcefg"[..], 0x000305)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn be_u24<'a, E: ParseError<&'a[u8]>>(i: &'a[u8]) -> IResult<&'a[u8], u32, E> {
  if i.len() < 3 {
    Err(Err::Error(make_error(i, ErrorKind::Eof)))
  } else {
    let res = ((i[0] as u32) << 16) + ((i[1] as u32) << 8) + (i[2] as u32);
    Ok((&i[3..], res))
  }
}

/// Recognizes a big endian unsigned 4 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::be_u32;
///
/// let parser = |s| {
///   be_u32(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03\x05\x07abcefg"), Ok((&b"abcefg"[..], 0x00030507)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn be_u32<'a, E: ParseError<&'a[u8]>>(i: &'a[u8]) -> IResult<&'a[u8], u32, E> {
  if i.len() < 4 {
    Err(Err::Error(make_error(i, ErrorKind::Eof)))
  } else {
    let res = ((i[0] as u32) << 24) + ((i[1] as u32) << 16) + ((i[2] as u32) << 8) + i[3] as u32;
    Ok((&i[4..], res))
  }
}

/// Recognizes a big endian unsigned 8 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::be_u64;
///
/// let parser = |s| {
///   be_u64(s)
/// };
///
/// assert_eq!(parser(b"\x00\x01\x02\x03\x04\x05\x06\x07abcefg"), Ok((&b"abcefg"[..], 0x0001020304050607)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn be_u64<'a, E: ParseError<&'a[u8]>>(i: &'a[u8]) -> IResult<&'a[u8], u64, E> {
  if i.len() < 8 {
    Err(Err::Error(make_error(i, ErrorKind::Eof)))
  } else {
    let res = ((i[0] as u64) << 56) + ((i[1] as u64) << 48) + ((i[2] as u64) << 40) + ((i[3] as u64) << 32) + ((i[4] as u64) << 24)
      + ((i[5] as u64) << 16) + ((i[6] as u64) << 8) + i[7] as u64;
    Ok((&i[8..], res))
  }
}

/// Recognizes a big endian unsigned 16 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::be_u128;
///
/// let parser = |s| {
///   be_u128(s)
/// };
///
/// assert_eq!(parser(b"\x00\x01\x02\x03\x04\x05\x06\x07\x00\x01\x02\x03\x04\x05\x06\x07abcefg"), Ok((&b"abcefg"[..], 0x00010203040506070001020304050607)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
#[cfg(stable_i128)]
pub fn be_u128<'a, E: ParseError<&'a[u8]>>(i: &'a[u8]) -> IResult<&'a[u8], u128, E> {
  if i.len() < 16 {
    Err(Err::Error(make_error(i, ErrorKind::Eof)))
  } else {
    let res = ((i[0] as u128) << 120)
      + ((i[1] as u128) << 112)
      + ((i[2] as u128) << 104)
      + ((i[3] as u128) << 96)
      + ((i[4] as u128) << 88)
      + ((i[5] as u128) << 80)
      + ((i[6] as u128) << 72)
      + ((i[7] as u128) << 64)
      + ((i[8] as u128) << 56)
      + ((i[9] as u128) << 48)
      + ((i[10] as u128) << 40)
      + ((i[11] as u128) << 32)
      + ((i[12] as u128) << 24)
      + ((i[13] as u128) << 16)
      + ((i[14] as u128) << 8)
      + i[15] as u128;
    Ok((&i[16..], res))
  }
}

/// Recognizes a signed 1 byte integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::be_i8;
///
/// let parser = |s| {
///   be_i8(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03abcefg"), Ok((&b"\x03abcefg"[..], 0x00)));
/// assert_eq!(parser(b""), Err(Err::Error((&[][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn be_i8<'a, E: ParseError<&'a[u8]>>(i: &'a[u8]) -> IResult<&'a[u8], i8, E> {
  map!(i, be_u8, |x| x as i8)
}

/// Recognizes a big endian signed 2 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::be_i16;
///
/// let parser = |s| {
///   be_i16(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03abcefg"), Ok((&b"abcefg"[..], 0x0003)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn be_i16<'a, E: ParseError<&'a [u8]>>(i: &'a[u8]) -> IResult<&'a[u8], i16, E> {
  map!(i, be_u16, |x| x as i16)
}

/// Recognizes a big endian signed 3 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::be_i24;
///
/// let parser = |s| {
///   be_i24(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03\x05abcefg"), Ok((&b"abcefg"[..], 0x000305)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn be_i24<'a, E: ParseError<&'a[u8]>>(i: &'a[u8]) -> IResult<&'a[u8], i32, E> {
  // Same as the unsigned version but we need to sign-extend manually here
  map!(i, be_u24, |x| if x & 0x80_00_00 != 0 {
    (x | 0xff_00_00_00) as i32
  } else {
    x as i32
  })
}

/// Recognizes a big endian signed 4 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::be_i32;
///
/// let parser = |s| {
///   be_i32(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03\x05\x07abcefg"), Ok((&b"abcefg"[..], 0x00030507)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn be_i32<'a, E: ParseError<&'a[u8]>>(i: &'a[u8]) -> IResult<&'a[u8], i32, E> {
  map!(i, be_u32, |x| x as i32)
}

/// Recognizes a big endian signed 8 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::be_i64;
///
/// let parser = |s| {
///   be_i64(s)
/// };
///
/// assert_eq!(parser(b"\x00\x01\x02\x03\x04\x05\x06\x07abcefg"), Ok((&b"abcefg"[..], 0x0001020304050607)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn be_i64<'a, E: ParseError<&'a[u8]>>(i: &'a[u8]) -> IResult<&'a[u8], i64, E> {
  map!(i, be_u64, |x| x as i64)
}

/// Recognizes a big endian signed 16 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::be_i128;
///
/// let parser = |s| {
///   be_i128(s)
/// };
///
/// assert_eq!(parser(b"\x00\x01\x02\x03\x04\x05\x06\x07\x00\x01\x02\x03\x04\x05\x06\x07abcefg"), Ok((&b"abcefg"[..], 0x00010203040506070001020304050607)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
#[cfg(stable_i128)]
pub fn be_i128<'a, E: ParseError<&'a [u8]>>(i: &'a[u8]) -> IResult<&'a[u8], i128, E> {
  map!(i, be_u128, |x| x as i128)
}

/// Recognizes an unsigned 1 byte integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::le_u8;
///
/// let parser = |s| {
///   le_u8(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03abcefg"), Ok((&b"\x03abcefg"[..], 0x00)));
/// assert_eq!(parser(b""), Err(Err::Error((&[][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn le_u8<'a, E: ParseError<&'a [u8]>>(i: &'a[u8]) -> IResult<&'a[u8], u8, E> {
  if i.len() < 1 {
    Err(Err::Error(make_error(i, ErrorKind::Eof)))
  } else {
    Ok((&i[1..], i[0]))
  }
}

/// Recognizes a little endian unsigned 2 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::le_u16;
///
/// let parser = |s| {
///   le_u16(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03abcefg"), Ok((&b"abcefg"[..], 0x0300)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn le_u16<'a, E: ParseError<&'a [u8]>>(i: &'a[u8]) -> IResult<&'a[u8], u16, E> {
  if i.len() < 2 {
    Err(Err::Error(make_error(i, ErrorKind::Eof)))
  } else {
    let res = ((i[1] as u16) << 8) + i[0] as u16;
    Ok((&i[2..], res))
  }
}

/// Recognizes a little endian unsigned 3 byte integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::le_u24;
///
/// let parser = |s| {
///   le_u24(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03\x05abcefg"), Ok((&b"abcefg"[..], 0x050300)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn le_u24<'a, E: ParseError<&'a [u8]>>(i: &'a[u8]) -> IResult<&'a[u8], u32, E> {
  if i.len() < 3 {
    Err(Err::Error(make_error(i, ErrorKind::Eof)))
  } else {
    let res = (i[0] as u32) + ((i[1] as u32) << 8) + ((i[2] as u32) << 16);
    Ok((&i[3..], res))
  }
}

/// Recognizes a little endian unsigned 4 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::le_u32;
///
/// let parser = |s| {
///   le_u32(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03\x05\x07abcefg"), Ok((&b"abcefg"[..], 0x07050300)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn le_u32<'a, E: ParseError<&'a [u8]>>(i: &'a[u8]) -> IResult<&'a[u8], u32, E> {
  if i.len() < 4 {
    Err(Err::Error(make_error(i, ErrorKind::Eof)))
  } else {
    let res = ((i[3] as u32) << 24) + ((i[2] as u32) << 16) + ((i[1] as u32) << 8) + i[0] as u32;
    Ok((&i[4..], res))
  }
}

/// Recognizes a little endian unsigned 8 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::le_u64;
///
/// let parser = |s| {
///   le_u64(s)
/// };
///
/// assert_eq!(parser(b"\x00\x01\x02\x03\x04\x05\x06\x07abcefg"), Ok((&b"abcefg"[..], 0x0706050403020100)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn le_u64<'a, E: ParseError<&'a [u8]>>(i: &'a[u8]) -> IResult<&'a[u8], u64, E> {
  if i.len() < 8 {
    Err(Err::Error(make_error(i, ErrorKind::Eof)))
  } else {
    let res = ((i[7] as u64) << 56) + ((i[6] as u64) << 48) + ((i[5] as u64) << 40) + ((i[4] as u64) << 32) + ((i[3] as u64) << 24)
      + ((i[2] as u64) << 16) + ((i[1] as u64) << 8) + i[0] as u64;
    Ok((&i[8..], res))
  }
}

/// Recognizes a little endian unsigned 16 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::le_u128;
///
/// let parser = |s| {
///   le_u128(s)
/// };
///
/// assert_eq!(parser(b"\x00\x01\x02\x03\x04\x05\x06\x07\x00\x01\x02\x03\x04\x05\x06\x07abcefg"), Ok((&b"abcefg"[..], 0x07060504030201000706050403020100)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
#[cfg(stable_i128)]
pub fn le_u128<'a, E: ParseError<&'a [u8]>>(i: &'a[u8]) -> IResult<&'a[u8], u128, E> {
  if i.len() < 16 {
    Err(Err::Error(make_error(i, ErrorKind::Eof)))
  } else {
    let res = ((i[15] as u128) << 120)
      + ((i[14] as u128) << 112)
      + ((i[13] as u128) << 104)
      + ((i[12] as u128) << 96)
      + ((i[11] as u128) << 88)
      + ((i[10] as u128) << 80)
      + ((i[9] as u128) << 72)
      + ((i[8] as u128) << 64)
      + ((i[7] as u128) << 56)
      + ((i[6] as u128) << 48)
      + ((i[5] as u128) << 40)
      + ((i[4] as u128) << 32)
      + ((i[3] as u128) << 24)
      + ((i[2] as u128) << 16)
      + ((i[1] as u128) << 8)
      + i[0] as u128;
    Ok((&i[16..], res))
  }
}

/// Recognizes a signed 1 byte integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::le_i8;
///
/// let parser = |s| {
///   le_i8(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03abcefg"), Ok((&b"\x03abcefg"[..], 0x00)));
/// assert_eq!(parser(b""), Err(Err::Error((&[][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn le_i8<'a, E: ParseError<&'a [u8]>>(i: &'a[u8]) -> IResult<&'a[u8], i8, E> {
  map!(i, le_u8, |x| x as i8)
}

/// Recognizes a little endian signed 2 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::le_i16;
///
/// let parser = |s| {
///   le_i16(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03abcefg"), Ok((&b"abcefg"[..], 0x0300)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn le_i16<'a, E: ParseError<&'a [u8]>>(i: &'a[u8]) -> IResult<&'a[u8], i16, E> {
  map!(i, le_u16, |x| x as i16)
}

/// Recognizes a little endian signed 3 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::le_i24;
///
/// let parser = |s| {
///   le_i24(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03\x05abcefg"), Ok((&b"abcefg"[..], 0x050300)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn le_i24<'a, E: ParseError<&'a [u8]>>(i: &'a[u8]) -> IResult<&'a[u8], i32, E> {
  // Same as the unsigned version but we need to sign-extend manually here
  map!(i, le_u24, |x| if x & 0x80_00_00 != 0 {
    (x | 0xff_00_00_00) as i32
  } else {
    x as i32
  })
}

/// Recognizes a little endian signed 4 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::le_i32;
///
/// let parser = |s| {
///   le_i32(s)
/// };
///
/// assert_eq!(parser(b"\x00\x03\x05\x07abcefg"), Ok((&b"abcefg"[..], 0x07050300)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn le_i32<'a, E: ParseError<&'a [u8]>>(i: &'a[u8]) -> IResult<&'a[u8], i32, E> {
  map!(i, le_u32, |x| x as i32)
}

/// Recognizes a little endian signed 8 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::le_i64;
///
/// let parser = |s| {
///   le_i64(s)
/// };
///
/// assert_eq!(parser(b"\x00\x01\x02\x03\x04\x05\x06\x07abcefg"), Ok((&b"abcefg"[..], 0x0706050403020100)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn le_i64<'a, E: ParseError<&'a [u8]>>(i: &'a[u8]) -> IResult<&'a[u8], i64, E> {
  map!(i, le_u64, |x| x as i64)
}

/// Recognizes a little endian signed 16 bytes integer
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::le_i128;
///
/// let parser = |s| {
///   le_i128(s)
/// };
///
/// assert_eq!(parser(b"\x00\x01\x02\x03\x04\x05\x06\x07\x00\x01\x02\x03\x04\x05\x06\x07abcefg"), Ok((&b"abcefg"[..], 0x07060504030201000706050403020100)));
/// assert_eq!(parser(b"\x01"), Err(Err::Error((&[0x01][..], ErrorKind::Eof))));
/// ```
#[inline]
#[cfg(stable_i128)]
pub fn le_i128<'a, E: ParseError<&'a [u8]>>(i: &'a[u8]) -> IResult<&'a[u8], i128, E> {
  map!(i, le_u128, |x| x as i128)
}

/// Recognizes a big endian 4 bytes floating point number
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::be_f32;
///
/// let parser = |s| {
///   be_f32(s)
/// };
///
/// assert_eq!(parser(&[0x41, 0x48, 0x00, 0x00][..]), Ok((&b""[..], 12.5)));
/// assert_eq!(parser(b"abc"), Err(Err::Error((&b"abc"[..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn be_f32<'a, E: ParseError<&'a [u8]>>(input: &'a[u8]) -> IResult<&'a[u8], f32, E> {
  match be_u32(input) {
    Err(e) => Err(e),
    Ok((i, o)) => Ok((i, f32::from_bits(o))),
  }
}

/// Recognizes a big endian 8 bytes floating point number
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::be_f64;
///
/// let parser = |s| {
///   be_f64(s)
/// };
///
/// assert_eq!(parser(&[0x40, 0x29, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00][..]), Ok((&b""[..], 12.5)));
/// assert_eq!(parser(b"abc"), Err(Err::Error((&b"abc"[..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn be_f64<'a, E: ParseError<&'a [u8]>>(input: &'a[u8]) -> IResult<&'a[u8], f64, E> {
  match be_u64(input) {
    Err(e) => Err(e),
    Ok((i, o)) => Ok((i, f64::from_bits(o))),
  }
}

/// Recognizes a little endian 4 bytes floating point number
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::le_f32;
///
/// let parser = |s| {
///   le_f32(s)
/// };
///
/// assert_eq!(parser(&[0x00, 0x00, 0x48, 0x41][..]), Ok((&b""[..], 12.5)));
/// assert_eq!(parser(b"abc"), Err(Err::Error((&b"abc"[..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn le_f32<'a, E: ParseError<&'a [u8]>>(input: &'a[u8]) -> IResult<&'a[u8], f32, E> {
  match le_u32(input) {
    Err(e) => Err(e),
    Ok((i, o)) => Ok((i, f32::from_bits(o))),
  }
}

/// Recognizes a little endian 8 bytes floating point number
///
/// *complete version*: returns an error if there is not enough input data
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::le_f64;
///
/// let parser = |s| {
///   le_f64(s)
/// };
///
/// assert_eq!(parser(&[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x29, 0x40][..]), Ok((&b""[..], 12.5)));
/// assert_eq!(parser(b"abc"), Err(Err::Error((&b"abc"[..], ErrorKind::Eof))));
/// ```
#[inline]
pub fn le_f64<'a, E: ParseError<&'a [u8]>>(input: &'a[u8]) -> IResult<&'a[u8], f64, E> {
  match le_u64(input) {
    Err(e) => Err(e),
    Ok((i, o)) => Ok((i, f64::from_bits(o))),
  }
}

/// Recognizes a hex-encoded integer
///
/// *complete version*: will parse until the end of input if it has less than 8 bytes
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::hex_u32;
///
/// let parser = |s| {
///   hex_u32(s)
/// };
///
/// assert_eq!(parser(b"01AE"), Ok((&b""[..], 0x01AE)));
/// assert_eq!(parser(b"abc"), Ok((&b""[..], 0x0ABC)));
/// assert_eq!(parser(b"ggg"), Err(Err::Error((&b"ggg"[..], ErrorKind::IsA))));
/// ```
#[inline]
pub fn hex_u32<'a, E: ParseError<&'a [u8]>>(input: &'a[u8]) -> IResult<&'a[u8], u32, E> {
  let (i, o) = crate::bytes::complete::is_a(&b"0123456789abcdefABCDEF"[..])(input)?;
  // Do not parse more than 8 characters for a u32
  let (parsed, remaining) = if o.len() <= 8 {
    (o, i)
  } else {
    (&input[..8], &input[8..])
  };

  let res = parsed
    .iter()
    .rev()
    .enumerate()
    .map(|(k, &v)| {
      let digit = v as char;
      digit.to_digit(16).unwrap_or(0) << (k * 4)
    })
    .sum();

  Ok((remaining, res))
}

/// Recognizes floating point number in a byte string and returns the corresponding slice
///
/// *complete version*: can parse until the end of input
///
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::recognize_float;
///
/// let parser = |s| {
///   recognize_float(s)
/// };
///
/// assert_eq!(parser("11e-1"), Ok(("", "11e-1")));
/// assert_eq!(parser("123E-02"), Ok(("", "123E-02")));
/// assert_eq!(parser("123K-01"), Ok(("K-01", "123")));
/// assert_eq!(parser("abc"), Err(Err::Error(("abc", ErrorKind::Char))));
/// ```
#[allow(unused_imports)]
#[cfg_attr(rustfmt, rustfmt_skip)]
pub fn recognize_float<T, E:ParseError<T>>(input: T) -> IResult<T, T, E>
where
  T: Slice<RangeFrom<usize>> + Slice<RangeTo<usize>>,
  T: Clone + Offset,
  T: InputIter,
  <T as InputIter>::Item: AsChar,
  T: InputTakeAtPosition,
  <T as InputTakeAtPosition>::Item: AsChar,
{
  recognize(
    tuple((
      opt(alt((char('+'), char('-')))),
      alt((
        map(tuple((digit1, opt(pair(char('.'), opt(digit1))))), |_| ()),
        map(tuple((char('.'), digit1)), |_| ())
      )),
      opt(tuple((
        alt((char('e'), char('E'))),
        opt(alt((char('+'), char('-')))),
        cut(digit1)
      )))
    ))
  )(input)
}

/// Recognizes floating point number in a byte string and returns a f32
///
/// *complete version*: can parse until the end of input
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::float;
///
/// let parser = |s| {
///   float(s)
/// };
///
/// assert_eq!(parser("11e-1"), Ok(("", 1.1)));
/// assert_eq!(parser("123E-02"), Ok(("", 1.23)));
/// assert_eq!(parser("123K-01"), Ok(("K-01", 123.0)));
/// assert_eq!(parser("abc"), Err(Err::Error(("abc", ErrorKind::Char))));
/// ```
#[cfg(not(feature = "lexical"))]
pub fn float<T, E:ParseError<T>>(input: T) -> IResult<T, f32, E>
where
  T: Slice<RangeFrom<usize>> + Slice<RangeTo<usize>>,
  T: Clone + Offset,
  T: InputIter + InputLength + crate::traits::ParseTo<f32>,
  <T as InputIter>::Item: AsChar,
  T: InputTakeAtPosition,
  <T as InputTakeAtPosition>::Item: AsChar
{
  match recognize_float(input) {
    Err(e) => Err(e),
    Ok((i, s)) => match s.parse_to() {
      Some(n) => Ok((i, n)),
      None =>  Err(Err::Error(E::from_error_kind(i, ErrorKind::Float)))
    }
  }
}

/// Recognizes floating point number in a byte string and returns a f32
///
/// *complete version*: can parse until the end of input
///
/// this function uses the lexical-core crate for float parsing by default, you
/// can deactivate it by removing the "lexical" feature
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::float;
///
/// let parser = |s| {
///   float(s)
/// };
///
/// assert_eq!(parser("1.1"), Ok(("", 1.1)));
/// assert_eq!(parser("123E-02"), Ok(("", 1.23)));
/// assert_eq!(parser("123K-01"), Ok(("K-01", 123.0)));
/// assert_eq!(parser("abc"), Err(Err::Error(("abc", ErrorKind::Float))));
/// ```
#[cfg(feature = "lexical")]
pub fn float<T, E:ParseError<T>>(input: T) -> IResult<T, f32, E>
where
  T: crate::traits::AsBytes + InputLength + Slice<RangeFrom<usize>>,
{
  match ::lexical_core::parse_partial(input.as_bytes()) {
    Ok((value, processed)) => Ok((input.slice(processed..), value)),
    Err(_) => Err(Err::Error(E::from_error_kind(input, ErrorKind::Float)))
  }
}

/// Recognizes floating point number in a byte string and returns a f64
///
/// *complete version*: can parse until the end of input
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::double;
///
/// let parser = |s| {
///   double(s)
/// };
///
/// assert_eq!(parser("11e-1"), Ok(("", 1.1)));
/// assert_eq!(parser("123E-02"), Ok(("", 1.23)));
/// assert_eq!(parser("123K-01"), Ok(("K-01", 123.0)));
/// assert_eq!(parser("abc"), Err(Err::Error(("abc", ErrorKind::Char))));
/// ```
#[cfg(not(feature = "lexical"))]
pub fn double<T, E:ParseError<T>>(input: T) -> IResult<T, f64, E>
where
  T: Slice<RangeFrom<usize>> + Slice<RangeTo<usize>>,
  T: Clone + Offset,
  T: InputIter + InputLength + crate::traits::ParseTo<f64>,
  <T as InputIter>::Item: AsChar,
  T: InputTakeAtPosition,
  <T as InputTakeAtPosition>::Item: AsChar
{
  match recognize_float(input) {
    Err(e) => Err(e),
    Ok((i, s)) => match s.parse_to() {
      Some(n) => Ok((i, n)),
      None =>  Err(Err::Error(E::from_error_kind(i, ErrorKind::Float)))
    }
  }
}

/// Recognizes floating point number in a byte string and returns a f64
///
/// *complete version*: can parse until the end of input
///
/// this function uses the lexical-core crate for float parsing by default, you
/// can deactivate it by removing the "lexical" feature
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed};
/// # use nom::Needed::Size;
/// use nom::number::complete::double;
///
/// let parser = |s| {
///   double(s)
/// };
///
/// assert_eq!(parser("1.1"), Ok(("", 1.1)));
/// assert_eq!(parser("123E-02"), Ok(("", 1.23)));
/// assert_eq!(parser("123K-01"), Ok(("K-01", 123.0)));
/// assert_eq!(parser("abc"), Err(Err::Error(("abc", ErrorKind::Float))));
/// ```
#[cfg(feature = "lexical")]
pub fn double<T, E:ParseError<T>>(input: T) -> IResult<T, f64, E>
where
  T: crate::traits::AsBytes + InputLength + Slice<RangeFrom<usize>>,
{
  match ::lexical_core::parse_partial(input.as_bytes()) {
    Ok((value, processed)) => Ok((input.slice(processed..), value)),
    Err(_) => Err(Err::Error(E::from_error_kind(input, ErrorKind::Float)))
  }
}

#[cfg(test)]
mod tests {
  use super::*;
  use crate::internal::Err;
  use crate::error::ErrorKind;

  macro_rules! assert_parse(
    ($left: expr, $right: expr) => {
      let res: $crate::IResult<_, _, (_, ErrorKind)> = $left;
      assert_eq!(res, $right);
    };
  );

  #[test]
  fn i8_tests() {
    assert_parse!(be_i8(&[0x00]), Ok((&b""[..], 0)));
    assert_parse!(be_i8(&[0x7f]), Ok((&b""[..], 127)));
    assert_parse!(be_i8(&[0xff]), Ok((&b""[..], -1)));
    assert_parse!(be_i8(&[0x80]), Ok((&b""[..], -128)));
  }

  #[test]
  fn i16_tests() {
    assert_parse!(be_i16(&[0x00, 0x00]), Ok((&b""[..], 0)));
    assert_parse!(be_i16(&[0x7f, 0xff]), Ok((&b""[..], 32_767_i16)));
    assert_parse!(be_i16(&[0xff, 0xff]), Ok((&b""[..], -1)));
    assert_parse!(be_i16(&[0x80, 0x00]), Ok((&b""[..], -32_768_i16)));
  }

  #[test]
  fn u24_tests() {
    assert_parse!(be_u24(&[0x00, 0x00, 0x00]), Ok((&b""[..], 0)));
    assert_parse!(be_u24(&[0x00, 0xFF, 0xFF]), Ok((&b""[..], 65_535_u32)));
    assert_parse!(be_u24(&[0x12, 0x34, 0x56]), Ok((&b""[..], 1_193_046_u32)));
  }

  #[test]
  fn i24_tests() {
    assert_parse!(be_i24(&[0xFF, 0xFF, 0xFF]), Ok((&b""[..], -1_i32)));
    assert_parse!(be_i24(&[0xFF, 0x00, 0x00]), Ok((&b""[..], -65_536_i32)));
    assert_parse!(be_i24(&[0xED, 0xCB, 0xAA]), Ok((&b""[..], -1_193_046_i32)));
  }

  #[test]
  fn i32_tests() {
    assert_parse!(be_i32(&[0x00, 0x00, 0x00, 0x00]), Ok((&b""[..], 0)));
    assert_parse!(
      be_i32(&[0x7f, 0xff, 0xff, 0xff]),
      Ok((&b""[..], 2_147_483_647_i32))
    );
    assert_parse!(be_i32(&[0xff, 0xff, 0xff, 0xff]), Ok((&b""[..], -1)));
    assert_parse!(
      be_i32(&[0x80, 0x00, 0x00, 0x00]),
      Ok((&b""[..], -2_147_483_648_i32))
    );
  }

  #[test]
  fn i64_tests() {
    assert_parse!(
      be_i64(&[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]),
      Ok((&b""[..], 0))
    );
    assert_parse!(
      be_i64(&[0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff]),
      Ok((&b""[..], 9_223_372_036_854_775_807_i64))
    );
    assert_parse!(
      be_i64(&[0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff]),
      Ok((&b""[..], -1))
    );
    assert_parse!(
      be_i64(&[0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]),
      Ok((&b""[..], -9_223_372_036_854_775_808_i64))
    );
  }

  #[test]
  #[cfg(stable_i128)]
  fn i128_tests() {
    assert_parse!(
      be_i128(&[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]),
      Ok((&b""[..], 0))
    );
    assert_parse!(
      be_i128(&[0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff]),
      Ok((&b""[..], 170_141_183_460_469_231_731_687_303_715_884_105_727_i128))
    );
    assert_parse!(
      be_i128(&[0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff]),
      Ok((&b""[..], -1))
    );
    assert_parse!(
      be_i128(&[0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]),
      Ok((&b""[..], -170_141_183_460_469_231_731_687_303_715_884_105_728_i128))
    );
  }

  #[test]
  fn le_i8_tests() {
    assert_parse!(le_i8(&[0x00]), Ok((&b""[..], 0)));
    assert_parse!(le_i8(&[0x7f]), Ok((&b""[..], 127)));
    assert_parse!(le_i8(&[0xff]), Ok((&b""[..], -1)));
    assert_parse!(le_i8(&[0x80]), Ok((&b""[..], -128)));
  }

  #[test]
  fn le_i16_tests() {
    assert_parse!(le_i16(&[0x00, 0x00]), Ok((&b""[..], 0)));
    assert_parse!(le_i16(&[0xff, 0x7f]), Ok((&b""[..], 32_767_i16)));
    assert_parse!(le_i16(&[0xff, 0xff]), Ok((&b""[..], -1)));
    assert_parse!(le_i16(&[0x00, 0x80]), Ok((&b""[..], -32_768_i16)));
  }

  #[test]
  fn le_u24_tests() {
    assert_parse!(le_u24(&[0x00, 0x00, 0x00]), Ok((&b""[..], 0)));
    assert_parse!(le_u24(&[0xFF, 0xFF, 0x00]), Ok((&b""[..], 65_535_u32)));
    assert_parse!(le_u24(&[0x56, 0x34, 0x12]), Ok((&b""[..], 1_193_046_u32)));
  }

  #[test]
  fn le_i24_tests() {
    assert_parse!(le_i24(&[0xFF, 0xFF, 0xFF]), Ok((&b""[..], -1_i32)));
    assert_parse!(le_i24(&[0x00, 0x00, 0xFF]), Ok((&b""[..], -65_536_i32)));
    assert_parse!(le_i24(&[0xAA, 0xCB, 0xED]), Ok((&b""[..], -1_193_046_i32)));
  }

  #[test]
  fn le_i32_tests() {
    assert_parse!(le_i32(&[0x00, 0x00, 0x00, 0x00]), Ok((&b""[..], 0)));
    assert_parse!(
      le_i32(&[0xff, 0xff, 0xff, 0x7f]),
      Ok((&b""[..], 2_147_483_647_i32))
    );
    assert_parse!(le_i32(&[0xff, 0xff, 0xff, 0xff]), Ok((&b""[..], -1)));
    assert_parse!(
      le_i32(&[0x00, 0x00, 0x00, 0x80]),
      Ok((&b""[..], -2_147_483_648_i32))
    );
  }

  #[test]
  fn le_i64_tests() {
    assert_parse!(
      le_i64(&[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]),
      Ok((&b""[..], 0))
    );
    assert_parse!(
      le_i64(&[0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f]),
      Ok((&b""[..], 9_223_372_036_854_775_807_i64))
    );
    assert_parse!(
      le_i64(&[0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff]),
      Ok((&b""[..], -1))
    );
    assert_parse!(
      le_i64(&[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80]),
      Ok((&b""[..], -9_223_372_036_854_775_808_i64))
    );
  }

  #[test]
  #[cfg(stable_i128)]
  fn le_i128_tests() {
    assert_parse!(
      le_i128(&[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]),
      Ok((&b""[..], 0))
    );
    assert_parse!(
      le_i128(&[0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f]),
      Ok((&b""[..], 170_141_183_460_469_231_731_687_303_715_884_105_727_i128))
    );
    assert_parse!(
      le_i128(&[0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff]),
      Ok((&b""[..], -1))
    );
    assert_parse!(
      le_i128(&[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80]),
      Ok((&b""[..], -170_141_183_460_469_231_731_687_303_715_884_105_728_i128))
    );
  }

  #[test]
  fn be_f32_tests() {
    assert_parse!(be_f32(&[0x00, 0x00, 0x00, 0x00]), Ok((&b""[..], 0_f32)));
    assert_parse!(
      be_f32(&[0x4d, 0x31, 0x1f, 0xd8]),
      Ok((&b""[..], 185_728_392_f32))
    );
  }

  #[test]
  fn be_f64_tests() {
    assert_parse!(
      be_f64(&[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]),
      Ok((&b""[..], 0_f64))
    );
    assert_parse!(
      be_f64(&[0x41, 0xa6, 0x23, 0xfb, 0x10, 0x00, 0x00, 0x00]),
      Ok((&b""[..], 185_728_392_f64))
    );
  }

  #[test]
  fn le_f32_tests() {
    assert_parse!(le_f32(&[0x00, 0x00, 0x00, 0x00]), Ok((&b""[..], 0_f32)));
    assert_parse!(
      le_f32(&[0xd8, 0x1f, 0x31, 0x4d]),
      Ok((&b""[..], 185_728_392_f32))
    );
  }

  #[test]
  fn le_f64_tests() {
    assert_parse!(
      le_f64(&[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]),
      Ok((&b""[..], 0_f64))
    );
    assert_parse!(
      le_f64(&[0x00, 0x00, 0x00, 0x10, 0xfb, 0x23, 0xa6, 0x41]),
      Ok((&b""[..], 185_728_392_f64))
    );
  }

  #[test]
  fn hex_u32_tests() {
    assert_parse!(
      hex_u32(&b";"[..]),
      Err(Err::Error(error_position!(&b";"[..], ErrorKind::IsA)))
    );
    assert_parse!(hex_u32(&b"ff;"[..]), Ok((&b";"[..], 255)));
    assert_parse!(hex_u32(&b"1be2;"[..]), Ok((&b";"[..], 7138)));
    assert_parse!(hex_u32(&b"c5a31be2;"[..]), Ok((&b";"[..], 3_315_801_058)));
    assert_parse!(hex_u32(&b"C5A31be2;"[..]), Ok((&b";"[..], 3_315_801_058)));
    assert_parse!(hex_u32(&b"00c5a31be2;"[..]), Ok((&b"e2;"[..], 12_952_347)));
    assert_parse!(
      hex_u32(&b"c5a31be201;"[..]),
      Ok((&b"01;"[..], 3_315_801_058))
    );
    assert_parse!(hex_u32(&b"ffffffff;"[..]), Ok((&b";"[..], 4_294_967_295)));
    assert_parse!(hex_u32(&b"0x1be2;"[..]), Ok((&b"x1be2;"[..], 0)));
    assert_parse!(hex_u32(&b"12af"[..]), Ok((&b""[..], 0x12af)));
  }

  #[test]
  #[cfg(feature = "std")]
  fn float_test() {
    let mut test_cases = vec![
      "+3.14",
      "3.14",
      "-3.14",
      "0",
      "0.0",
      "1.",
      ".789",
      "-.5",
      "1e7",
      "-1E-7",
      ".3e-2",
      "1.e4",
      "1.2e4",
      "12.34",
      "-1.234E-12",
      "-1.234e-12",
    ];

    for test in test_cases.drain(..) {
      let expected32 = str::parse::<f32>(test).unwrap();
      let expected64 = str::parse::<f64>(test).unwrap();

      println!("now parsing: {} -> {}", test, expected32);

      let larger = format!("{}", test);
      assert_parse!(recognize_float(&larger[..]), Ok(("", test)));

      assert_parse!(float(larger.as_bytes()), Ok((&b""[..], expected32)));
      assert_parse!(float(&larger[..]), Ok(("", expected32)));

      assert_parse!(double(larger.as_bytes()), Ok((&b""[..], expected64)));
      assert_parse!(double(&larger[..]), Ok(("", expected64)));
    }

    let remaining_exponent = "-1.234E-";
    assert_parse!(
      recognize_float(remaining_exponent),
      Err(Err::Failure(("", ErrorKind::Digit)))
    );
  }

}