From 0f85c34a26bab92e6ba7cf3380b8d5b278254103 Mon Sep 17 00:00:00 2001
From: Clar Charr <clar@charr.xyz>
Date: Fri, 9 Mar 2018 13:44:35 -0500
Subject: [PATCH] Allow "infinity" and ignore case when parsing floats.

---
 src/libcore/num/dec2flt/mod.rs       | 18 +++++++++++++-----
 src/libcore/tests/num/dec2flt/mod.rs | 14 +++++++++++---
 2 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/src/libcore/num/dec2flt/mod.rs b/src/libcore/num/dec2flt/mod.rs
index f93564c2849f5..be34541841fe7 100644
--- a/src/libcore/num/dec2flt/mod.rs
+++ b/src/libcore/num/dec2flt/mod.rs
@@ -123,7 +123,8 @@ macro_rules! from_str_float_impl {
             /// * '2.5E-10'
             /// * '5.'
             /// * '.5', or, equivalently,  '0.5'
-            /// * 'inf', '-inf', 'NaN'
+            /// * 'inf', `-inf`, or equivalently 'infinity', `-infinity` (case-insensitive)
+            /// * 'NaN' (case-insensitive)
             ///
             /// Leading and trailing whitespace represent an error.
             ///
@@ -215,10 +216,17 @@ fn dec2flt<T: RawFloat>(s: &str) -> Result<T, ParseFloatError> {
         ParseResult::Valid(decimal) => convert(decimal)?,
         ParseResult::ShortcutToInf => T::INFINITY,
         ParseResult::ShortcutToZero => T::ZERO,
-        ParseResult::Invalid => match s {
-            "inf" => T::INFINITY,
-            "NaN" => T::NAN,
-            _ => { return Err(pfe_invalid()); }
+        ParseResult::Invalid => {
+            let buf = [0; 8]
+                .get_mut(..s.len())
+                .ok_or_else(pfe_invalid)?;
+            buf.copy_from_slice(s.as_bytes());
+            buf.make_ascii_uppercase();
+            match &*buf {
+                b"INFINITY" | b"INF" => T::INFINITY,
+                b"NAN" => T::NAN,
+                _ => { return Err(pfe_invalid()); }
+            }
         }
     };
 
diff --git a/src/libcore/tests/num/dec2flt/mod.rs b/src/libcore/tests/num/dec2flt/mod.rs
index 17b2f59cd4df2..2e75cbafdc8b8 100644
--- a/src/libcore/tests/num/dec2flt/mod.rs
+++ b/src/libcore/tests/num/dec2flt/mod.rs
@@ -122,15 +122,23 @@ fn whitespace() {
 #[test]
 fn nan() {
     assert!("NaN".parse::<f32>().unwrap().is_nan());
+    assert!("NAN".parse::<f32>().unwrap().is_nan());
+    assert!("nan".parse::<f32>().unwrap().is_nan());
     assert!("NaN".parse::<f64>().unwrap().is_nan());
+    assert!("NAN".parse::<f64>().unwrap().is_nan());
+    assert!("nan".parse::<f64>().unwrap().is_nan());
 }
 
 #[test]
 fn inf() {
-    assert_eq!("inf".parse(), Ok(f64::INFINITY));
-    assert_eq!("-inf".parse(), Ok(f64::NEG_INFINITY));
-    assert_eq!("inf".parse(), Ok(f32::INFINITY));
+    assert_eq!("INF".parse(), Ok(f32::INFINITY));
     assert_eq!("-inf".parse(), Ok(f32::NEG_INFINITY));
+    assert_eq!("INFINITy".parse(), Ok(f32::INFINITY));
+    assert_eq!("-infinitY".parse(), Ok(f32::NEG_INFINITY));
+    assert_eq!("INF".parse(), Ok(f64::INFINITY));
+    assert_eq!("-inf".parse(), Ok(f64::NEG_INFINITY));
+    assert_eq!("INFINITy".parse(), Ok(f64::INFINITY));
+    assert_eq!("-infinitY".parse(), Ok(f64::NEG_INFINITY));
 }
 
 #[test]