Merge pull request #114 from serde-rs/large

Error on large numbers instead of parsing infinity
serde-rs · Jul 12, 2016 · b61d90d · b61d90d
2 parents 02be472 + 09340cb
commit b61d90d
Show file tree

Hide file tree

Showing 3 changed files with 102 additions and 22 deletions.
diff --git a/json/src/de.rs b/json/src/de.rs
@@ -404,12 +404,7 @@ impl<R: Read> DeserializerImpl<R> {
             let digit = (c - b'0') as i32;
 
             if overflow!(exp * 10 + digit, i32::MAX) {
-                // Really big exponent, just ignore the rest.
-                while let b'0' ... b'9' = try!(self.peek_or_null()) {
-                    self.eat_char();
-                }
-                exp = i32::MAX;
-                break;
+                return self.parse_exponent_overflow(pos, significand, pos_exp, visitor);
             }
 
             exp = exp * 10 + digit;
@@ -424,29 +419,63 @@ impl<R: Read> DeserializerImpl<R> {
         self.visit_f64_from_parts(pos, significand, final_exp, visitor)
     }
 
+    // This cold code should not be inlined into the middle of the hot
+    // exponent-parsing loop above.
+    #[cold]
+    #[inline(never)]
+    // https://github.com/Manishearth/rust-clippy/issues/1086
+    #[cfg_attr(feature = "clippy", allow(if_same_then_else))]
+    fn parse_exponent_overflow<V>(&mut self,
+                                  pos: bool,
+                                  significand: u64,
+                                  pos_exp: bool,
+                                  mut visitor: V) -> Result<V::Value>
+        where V: de::Visitor,
+    {
+        // Error instead of +/- infinity.
+        if significand != 0 && pos_exp {
+            return Err(self.error(ErrorCode::NumberOutOfRange));
+        }
+
+        while let b'0' ... b'9' = try!(self.peek_or_null()) {
+            self.eat_char();
+        }
+        visitor.visit_f64(if pos { 0.0 } else { -0.0 })
+    }
+
     fn visit_f64_from_parts<V>(&mut self,
                                pos: bool,
                                significand: u64,
-                               exponent: i32,
+                               mut exponent: i32,
                                mut visitor: V) -> Result<V::Value>
         where V: de::Visitor,
     {
-        let f = match POW10.get(exponent.abs() as usize) {
-            Some(pow) => {
-                if exponent >= 0 {
-                    significand as f64 * pow
-                } else {
-                    significand as f64 / pow
+        let mut f = significand as f64;
+        loop {
+            match POW10.get(exponent.abs() as usize) {
+                Some(&pow) => {
+                    if exponent >= 0 {
+                        f *= pow;
+                        if f.is_infinite() {
+                            return Err(self.error(ErrorCode::NumberOutOfRange));
+                        }
+                    } else {
+                        f /= pow;
+                    }
+                    break;
                 }
-            }
-            None => {
-                if exponent >= 0 && significand != 0 {
-                    f64::INFINITY
-                } else {
-                    0.0
+                None => {
+                    if f == 0.0 {
+                        break;
+                    }
+                    if exponent >= 0 {
+                        return Err(self.error(ErrorCode::NumberOutOfRange));
+                    }
+                    f /= 1e308;
+                    exponent += 308;
                 }
             }
-        };
+        }
         visitor.visit_f64(if pos { f } else { -f })
     }
 

diff --git a/json/src/error.rs b/json/src/error.rs
@@ -68,6 +68,9 @@ pub enum ErrorCode {
     /// Invalid number.
     InvalidNumber,
 
+    /// Number is bigger than the maximum value of its type.
+    NumberOutOfRange,
+
     /// Invalid unicode code point.
     InvalidUnicodeCodePoint,
 
@@ -105,6 +108,7 @@ impl fmt::Display for ErrorCode {
             ErrorCode::ExpectedSomeValue => "expected value".fmt(f),
             ErrorCode::InvalidEscape => "invalid escape".fmt(f),
             ErrorCode::InvalidNumber => "invalid number".fmt(f),
+            ErrorCode::NumberOutOfRange => "number out of range".fmt(f),
             ErrorCode::InvalidUnicodeCodePoint => "invalid unicode code point".fmt(f),
             ErrorCode::KeyMustBeAString => "key must be a string".fmt(f),
             ErrorCode::LoneLeadingSurrogateInHexEscape => "lone leading surrogate in hex escape".fmt(f),

diff --git a/json_tests/tests/test_json.rs b/json_tests/tests/test_json.rs
@@ -788,6 +788,29 @@ fn test_parse_number_errors() {
         ("1e", Error::Syntax(ErrorCode::InvalidNumber, 1, 2)),
         ("1e+", Error::Syntax(ErrorCode::InvalidNumber, 1, 3)),
         ("1a", Error::Syntax(ErrorCode::TrailingCharacters, 1, 2)),
+        ("100e777777777777777777777777777", Error::Syntax(ErrorCode::NumberOutOfRange, 1, 14)),
+        ("-100e777777777777777777777777777", Error::Syntax(ErrorCode::NumberOutOfRange, 1, 15)),
+        ("1000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000", // 1e309
+           Error::Syntax(ErrorCode::NumberOutOfRange, 1, 310)),
+        ("1000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           .0e9", // 1e309
+           Error::Syntax(ErrorCode::NumberOutOfRange, 1, 305)),
+        ("1000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           e9", // 1e309
+           Error::Syntax(ErrorCode::NumberOutOfRange, 1, 303)),
     ]);
 }
 
@@ -819,6 +842,7 @@ fn test_parse_negative_zero() {
         "-0e2",
         "-0.0e2",
         "-1e-400",
+        "-1e-4000000000000000000000000000000000000000000000000",
     ] {
         assert_eq!(0, from_str::<u32>(negative_zero).unwrap());
         assert!(from_str::<f64>(negative_zero).unwrap().is_sign_negative(),
@@ -850,11 +874,34 @@ fn test_parse_f64() {
         (&format!("{:?}", (u64::MAX as f64) + 1.0), (u64::MAX as f64) + 1.0),
         (&format!("{:?}", f64::EPSILON), f64::EPSILON),
         ("0.0000000000000000000000000000000000000000000000000123e50", 1.23),
-        ("100e777777777777777777777777777", f64::INFINITY),
-        ("-100e777777777777777777777777777", f64::NEG_INFINITY),
         ("100e-777777777777777777777777777", 0.0),
         ("1010101010101010101010101010101010101010", 10101010101010101010e20),
         ("0.1010101010101010101010101010101010101010", 0.1010101010101010101),
+        ("0e1000000000000000000000000000000000000000000000", 0.0),
+        ("1000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           00000000", 1e308),
+        ("1000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           .0e8", 1e308),
+        ("1000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           e8", 1e308),
+        ("1000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000000000000000000000000000000000000000000000\
+           000000000000000000e-10", 1e308),
     ]);
 }