Be smarter about integer deserialization

src/de/mod.rs

@@ -6,7 +6,7 @@ use serde::de::{self, DeserializeSeed, Deserializer as SerdeError, Visitor};
 use std::{borrow::Cow, io, str};
 
 use self::id::IdDeserializer;
-use crate::parse::{Bytes, Extensions, ParsedStr};
+use crate::parse::{AnyNum, Bytes, Extensions, ParsedStr};
 
 mod error;
 mod id;
@@ -148,10 +148,19 @@ impl<'de, 'a> de::Deserializer<'de> for &'a mut Deserializer<'de> {
             b'[' => self.deserialize_seq(visitor),
             b'{' => self.deserialize_map(visitor),
             b'0'..=b'9' | b'+' | b'-' => {
-                if self.bytes.next_bytes_is_float() {
-                    self.deserialize_f64(visitor)
-                } else {
-                    self.deserialize_i64(visitor)
+                let any_num: AnyNum = self.bytes.any_num()?;
+
+                match any_num {
+                    AnyNum::F32(x) => visitor.visit_f32(x),
+                    AnyNum::F64(x) => visitor.visit_f64(x),
+                    AnyNum::I8(x) => visitor.visit_i8(x),
+                    AnyNum::U8(x) => visitor.visit_u8(x),
+                    AnyNum::I16(x) => visitor.visit_i16(x),
+                    AnyNum::U16(x) => visitor.visit_u16(x),
+                    AnyNum::I32(x) => visitor.visit_i32(x),
+                    AnyNum::U32(x) => visitor.visit_u32(x),
+                    AnyNum::I64(x) => visitor.visit_i64(x),
+                    AnyNum::U64(x) => visitor.visit_u64(x),
                 }
             }
             b'.' => self.deserialize_f64(visitor),

src/de/tests.rs

@@ -305,3 +305,18 @@ fn test_numbers() {
         from_str("[1_234, 12_345, 1_2_3_4_5_6, 1_234_567, 5_55_55_5]"),
     );
 }
+
+fn de_any_number(s: &str) -> AnyNum {
+    let mut bytes = Bytes::new(s.as_bytes()).unwrap();
+
+    bytes.any_num().unwrap()
+}
+
+#[test]
+fn test_any_number_precision() {
+    assert_eq!(de_any_number("1"), AnyNum::U8(1));
+    assert_eq!(de_any_number("+1"), AnyNum::I8(1));
+    assert_eq!(de_any_number("-1"), AnyNum::I8(-1));
+    assert_eq!(de_any_number("-1.0"), AnyNum::F32(-1.0));
+    assert_eq!(de_any_number("0.3"), AnyNum::F64(0.3));
+}

src/parse.rs

@@ -15,6 +15,20 @@ const IDENT_FIRST: &[u8] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxy
 const IDENT_CHAR: &[u8] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz_0123456789";
 const WHITE_SPACE: &[u8] = b"\n\t\r ";
 
+#[derive(Clone, Debug, PartialEq)]
+pub enum AnyNum {
+    F32(f32),
+    F64(f64),
+    I8(i8),
+    U8(u8),
+    I16(i16),
+    U16(u16),
+    I32(i32),
+    U32(u32),
+    I64(i64),
+    U64(u64),
+}
+
 #[derive(Clone, Copy, Debug)]
 pub struct Bytes<'a> {
     /// Bits set according to `Extension` enum.
@@ -70,6 +84,79 @@ impl<'a> Bytes<'a> {
         Ok(())
     }
 
+    pub fn any_num(&mut self) -> Result<AnyNum> {
+        fn any_float(f: f64) -> Result<AnyNum> {
+            if f == f as f32 as f64 {
+                Ok(AnyNum::F32(f as f32))
+            } else {
+                Ok(AnyNum::F64(f))
+            }
+        }
+
+        let bytes_backup = self.bytes;
+
+        let first_byte = self.peek_or_eof()?;
+        let is_signed = first_byte == b'-' || first_byte == b'+';
+        let is_float = self.next_bytes_is_float();
+
+        if is_float {
+            let f = self.float::<f64>()?;
+
+            any_float(f)
+        } else {
+            let max_u8 = std::u8::MAX as u64;
+            let max_u16 = std::u16::MAX as u64;
+            let max_u32 = std::u32::MAX as u64;
+
+            let min_i8 = std::i8::MIN as i64;
+            let max_i8 = std::i8::MAX as i64;
+            let min_i16 = std::i16::MIN as i64;
+            let max_i16 = std::i16::MAX as i64;
+            let min_i32 = std::i32::MIN as i64;
+            let max_i32 = std::i32::MAX as i64;
+
+            if is_signed {
+                match self.signed_integer::<i64>() {
+                    Ok(x) => {
+                        if x >= min_i8 && x <= max_i8 {
+                            Ok(AnyNum::I8(x as i8))
+                        } else if x >= min_i16 && x <= max_i16 {
+                            Ok(AnyNum::I16(x as i16))
+                        } else if x >= min_i32 && x <= max_i32 {
+                            Ok(AnyNum::I32(x as i32))
+                        } else {
+                            Ok(AnyNum::I64(x))
+                        }
+                    }
+                    Err(_) => {
+                        self.bytes = bytes_backup;
+
+                        any_float(self.float::<f64>()?)
+                    }
+                }
+            } else {
+                match self.unsigned_integer::<u64>() {
+                    Ok(x) => {
+                        if x <= max_u8 {
+                            Ok(AnyNum::U8(x as u8))
+                        } else if x <= max_u16 {
+                            Ok(AnyNum::U16(x as u16))
+                        } else if x <= max_u32 {
+                            Ok(AnyNum::U32(x as u32))
+                        } else {
+                            Ok(AnyNum::U64(x))
+                        }
+                    }
+                    Err(_) => {
+                        self.bytes = bytes_backup;
+
+                        any_float(self.float::<f64>()?)
+                    }
+                }
+            }
+        }
+    }
+
     pub fn bool(&mut self) -> Result<bool> {
         if self.consume("true") {
             Ok(true)

tests/large_number.rs

@@ -0,0 +1,12 @@
+use ron::value::Number;
+
+#[test]
+fn test_large_number() {
+    use ron::value::Value;
+    let test_var = Value::Number(Number::new(10000000000000000000000.0f64));
+    let test_ser = ron::ser::to_string(&test_var).unwrap();
+    println!("test_ser: {}", test_ser);
+    let test_deser = ron::de::from_str::<Value>(&test_ser);
+
+    assert_eq!(test_deser.unwrap(), Value::Number(Number::new(10000000000000000000000.0)));
+}