Fixes #1384, by ensuring specials are properly parsed.

Author: Alexhuszagh

src/number/complete.rs

@@ -1,5 +1,6 @@
 //! Parsers recognizing numbers, complete input version
 
+use core::{f32, f64};
 use crate::branch::alt;
 use crate::bytes::complete::tag;
 use crate::character::complete::{char, digit1, sign};
@@ -1426,6 +1427,8 @@ where
   )(input)
 }
 
+///
+
 /// Recognizes a floating point number in text format and returns the integer, fraction and exponent parts of the input data
 ///
 /// *Complete version*: Can parse until the end of input.
@@ -1517,24 +1520,35 @@ where
   Ok((i, (sign, integer, fraction, exp)))
 }
 
+/// Case-insensitive comparison of digits. Only works if `y` is only ASCII letters.
+#[inline]
+fn case_insensitive_cmp(x: &[u8], y: &[u8]) -> bool {
+    let d = (x.iter().zip(y.iter())).fold(0, |d, (xi, yi)| d | xi ^ yi);
+    // This uses the trick that 'a' - 'A' == 0x20, and this is true
+    // for all characters, so as long as `yi` is a valid ASCII letter,
+    // `xi ^ yi` can only be 0 or 0x20.
+    d == 0 || d == 32
+}
+
 /// Recognizes floating point number in text format and returns a f32.
 ///
-/// *Complete version*: Can parse until the end of input.
+/// *Complete version*: Can parse until the end of input. This only handles
+/// finite (non-special floats).
 /// ```rust
 /// # use nom::{Err, error::ErrorKind, Needed};
 /// # use nom::Needed::Size;
-/// use nom::number::complete::float;
+/// use nom::number::complete::float_finite;
 ///
 /// let parser = |s| {
-///   float(s)
+///   float_finite(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::Float))));
 /// ```
-pub fn float<T, E: ParseError<T>>(input: T) -> IResult<T, f32, E>
+pub fn float_finite<T, E: ParseError<T>>(input: T) -> IResult<T, f32, E>
 where
   T: Slice<RangeFrom<usize>> + Slice<RangeTo<usize>> + Slice<Range<usize>>,
   T: Clone + Offset,
@@ -1560,6 +1574,42 @@ where
   Ok((i, float))
 }
 
+/// Recognizes floating point number in text format and returns a f32.
+/// This only handles non-finite (special) values.
+pub fn float_nonfinite<T, E: ParseError<T>>(input: T) -> IResult<T, f32, E>
+where
+  T: Slice<RangeFrom<usize>> + Slice<RangeTo<usize>> + Slice<Range<usize>>,
+  T: Clone + Offset,
+  T: InputIter + InputLength + InputTake,
+  <T as InputIter>::Item: AsChar + Copy,
+  <T as InputIter>::IterElem: Clone,
+  T: InputTakeAtPosition,
+  <T as InputTakeAtPosition>::Item: AsChar,
+  T: AsBytes,
+  T: for<'a> Compare<&'a [u8]>,
+{
+  let (i, sign) = sign(input.clone())?;
+  let (mut float, count) = if i.input_len() >= 3 {
+    if case_insensitive_cmp(i.as_bytes(), b"nan") {
+      (f32::NAN, 3)
+    } else if i.input_len() >= 8 && case_insensitive_cmp(i.as_bytes(), b"infinity") {
+      (f32::INFINITY, 8)
+    } else if case_insensitive_cmp(i.as_bytes(), b"inf") {
+      (f32::INFINITY, 3)
+    } else {
+      return Err(Err::Error(E::from_error_kind(input, ErrorKind::Float)));
+    }
+  } else {
+    return Err(Err::Error(E::from_error_kind(input, ErrorKind::Float)));
+  };
+
+  if !sign {
+    float = -float;
+  }
+
+  Ok((i.slice(count..), float))
+}
+
 /// Recognizes floating point number in text format and returns a f32.
 ///
 /// *Complete version*: Can parse until the end of input.
@@ -1577,7 +1627,44 @@ where
 /// assert_eq!(parser("123K-01"), Ok(("K-01", 123.0)));
 /// assert_eq!(parser("abc"), Err(Err::Error(("abc", ErrorKind::Float))));
 /// ```
-pub fn double<T, E: ParseError<T>>(input: T) -> IResult<T, f64, E>
+pub fn float<T, E: ParseError<T>>(input: T) -> IResult<T, f32, E>
+where
+  T: Slice<RangeFrom<usize>> + Slice<RangeTo<usize>> + Slice<Range<usize>>,
+  T: Clone + Offset,
+  T: InputIter + InputLength + InputTake,
+  <T as InputIter>::Item: AsChar + Copy,
+  <T as InputIter>::IterElem: Clone,
+  T: InputTakeAtPosition,
+  <T as InputTakeAtPosition>::Item: AsChar,
+  T: AsBytes,
+  T: for<'a> Compare<&'a [u8]>,
+{
+  if let Ok((i, float)) = float_finite::<T, E>(input.clone()) {
+    Ok((i, float))
+  } else {
+    float_nonfinite::<T, E>(input)
+  }
+}
+
+/// Recognizes floating point number in text format and returns a f64.
+///
+/// *Complete version*: Can parse until the end of input. This only handles
+/// finite (non-special floats).
+/// ```rust
+/// # use nom::{Err, error::ErrorKind, Needed};
+/// # use nom::Needed::Size;
+/// use nom::number::complete::double_finite;
+///
+/// let parser = |s| {
+///   double_finite(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::Float))));
+/// ```
+pub fn double_finite<T, E: ParseError<T>>(input: T) -> IResult<T, f64, E>
 where
   T: Slice<RangeFrom<usize>> + Slice<RangeTo<usize>> + Slice<Range<usize>>,
   T: Clone + Offset,
@@ -1603,6 +1690,78 @@ where
   Ok((i, float))
 }
 
+/// Recognizes floating point number in text format and returns a f64.
+/// This only handles non-finite (special) values.
+pub fn double_nonfinite<T, E: ParseError<T>>(input: T) -> IResult<T, f64, E>
+where
+  T: Slice<RangeFrom<usize>> + Slice<RangeTo<usize>> + Slice<Range<usize>>,
+  T: Clone + Offset,
+  T: InputIter + InputLength + InputTake,
+  <T as InputIter>::Item: AsChar + Copy,
+  <T as InputIter>::IterElem: Clone,
+  T: InputTakeAtPosition,
+  <T as InputTakeAtPosition>::Item: AsChar,
+  T: AsBytes,
+  T: for<'a> Compare<&'a [u8]>,
+{
+  let (i, sign) = sign(input.clone())?;
+  let (mut double, count) = if i.input_len() >= 3 {
+    if case_insensitive_cmp(i.as_bytes(), b"nan") {
+      (f64::NAN, 3)
+    } else if i.input_len() >= 8 && case_insensitive_cmp(i.as_bytes(), b"infinity") {
+      (f64::INFINITY, 8)
+    } else if case_insensitive_cmp(i.as_bytes(), b"inf") {
+      (f64::INFINITY, 3)
+    } else {
+      return Err(Err::Error(E::from_error_kind(input, ErrorKind::Float)));
+    }
+  } else {
+    return Err(Err::Error(E::from_error_kind(input, ErrorKind::Float)));
+  };
+
+  if !sign {
+    double = -double;
+  }
+
+  Ok((i.slice(count..), double))
+}
+
+/// Recognizes floating point number in text format 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::Float))));
+/// ```
+pub fn double<T, E: ParseError<T>>(input: T) -> IResult<T, f64, E>
+where
+  T: Slice<RangeFrom<usize>> + Slice<RangeTo<usize>> + Slice<Range<usize>>,
+  T: Clone + Offset,
+  T: InputIter + InputLength + InputTake,
+  <T as InputIter>::Item: AsChar + Copy,
+  <T as InputIter>::IterElem: Clone,
+  T: InputTakeAtPosition,
+  <T as InputTakeAtPosition>::Item: AsChar,
+  T: AsBytes,
+  T: for<'a> Compare<&'a [u8]>,
+{
+  match double_finite::<T, E>(input.clone()) {
+    Ok((i, double)) => Ok((i, double)),
+    Err(Err::Incomplete(e)) => Err(Err::Incomplete(e)),
+    _ => double_nonfinite::<T, E>(input),
+  }
+}
+
 #[cfg(test)]
 mod tests {
   use super::*;
@@ -1618,6 +1777,23 @@ mod tests {
     };
   );
 
+  // Need more complex logic, since NaN != NaN.
+  macro_rules! assert_float_eq {
+    ($left: expr, $right: expr) => {
+      let left: $crate::IResult<_, _, (_, ErrorKind)> = $left;
+      let right: $crate::IResult<_, _, (_, ErrorKind)> = $right;
+      if let Ok((_, float)) = right {
+        if float.is_nan() {
+          assert!(left.unwrap().1.is_nan());
+        } else {
+          assert_eq!(left, right);
+        }
+      }else {
+        assert_eq!(left, right);
+      }
+    };
+  }
+
   #[test]
   fn i8_tests() {
     assert_parse!(i8(&[0x00][..]), Ok((&b""[..], 0)));
@@ -1942,6 +2118,8 @@ mod tests {
       "12.34",
       "-1.234E-12",
       "-1.234e-12",
+      "NaN",
+      "inf",
     ];
 
     for test in test_cases.drain(..) {
@@ -1951,13 +2129,15 @@ mod tests {
       println!("now parsing: {} -> {}", test, expected32);
 
       let larger = format!("{}", test);
-      assert_parse!(recognize_float(&larger[..]), Ok(("", test)));
+      if expected32.is_finite() {
+        assert_parse!(recognize_float(&larger[..]), Ok(("", test)));
+      }
 
-      assert_parse!(float(larger.as_bytes()), Ok((&b""[..], expected32)));
-      assert_parse!(float(&larger[..]), Ok(("", expected32)));
+      assert_float_eq!(float(larger.as_bytes()), Ok((&b""[..], expected32)));
+      assert_float_eq!(float(&larger[..]), Ok(("", expected32)));
 
-      assert_parse!(double(larger.as_bytes()), Ok((&b""[..], expected64)));
-      assert_parse!(double(&larger[..]), Ok(("", expected64)));
+      assert_float_eq!(double(larger.as_bytes()), Ok((&b""[..], expected64)));
+      assert_float_eq!(double(&larger[..]), Ok(("", expected64)));
     }
 
     let remaining_exponent = "-1.234E-";
@@ -2051,8 +2231,8 @@ mod tests {
   }
 
   fn parse_f64(i: &str) -> IResult<&str, f64, ()> {
-    match recognize_float(i) {
-      Err(e) => Err(e),
+    match recognize_float::<_, ()>(i) {
+      Err(_) => Err(Err::Error(())),
       Ok((i, s)) => {
         if s.is_empty() {
           return Err(Err::Error(()));