size 0.5.0

A crate for expressing, formatting, and interacting with file sizes
Documentation 
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use crate::Size;
use serde::de;
use serde::{Deserialize, Deserializer, Serialize, Serializer};
use std::fmt;

struct SizeVisitor;

impl<'de> de::Visitor<'de> for SizeVisitor {
    type Value = Size;

    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        formatter.write_str("an integer or a floating point number representing size in bytes")
    }

    fn visit_i64<E>(self, value: i64) -> Result<Self::Value, E>
    where
        E: de::Error,
    {
        Ok(Size { bytes: value })
    }

    fn visit_u64<E>(self, value: u64) -> Result<Self::Value, E>
    where
        E: de::Error,
    {
        if value > i64::MAX as u64 {
            Err(E::custom(format!("u64 size {} is out of range", value)))
        } else {
            Ok(Size {
                bytes: value as i64,
            })
        }
    }

    fn visit_f32<E>(self, value: f32) -> Result<Self::Value, E>
    where
        E: de::Error,
    {
        if value.is_infinite() || value > i64::MAX as f32 || value < i64::MIN as f32 {
            Err(E::custom(format!("f32 size {} is out of range", value)))
        } else {
            Ok(Size {
                bytes: value as i64,
            })
        }
    }

    fn visit_f64<E>(self, value: f64) -> Result<Self::Value, E>
    where
        E: de::Error,
    {
        if value.is_infinite() || value > i64::MAX as f64 || value < i64::MIN as f64 {
            Err(E::custom(format!("f64 size {} is out of range", value)))
        } else {
            Ok(Size {
                bytes: value as i64,
            })
        }
    }

    fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
    where
        E: de::Error,
    {
        Size::from_str(value).map_err(|_| E::custom(format!("Invalid size: \"{value}\"")))
    }
}

impl Serialize for Size {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        serializer.serialize_i64(self.bytes)
    }
}

impl<'de> Deserialize<'de> for Size {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        deserializer.deserialize_any(SizeVisitor)
    }
}

#[test]
/// Assert that [`Size`] serializes to its inner value directly
fn test_serialize() {
    use serde::{Deserialize, Serialize};

    #[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
    struct Foo {
        size: Size,
    }

    let foo = Foo {
        size: Size::from_bytes(1024),
    };
    let json = serde_json::to_string(&foo);
    assert_eq!(json.as_ref().unwrap(), &r#"{"size":1024}"#.to_string());
}

#[test]
fn test_deserialize_i64() {
    use serde::{Deserialize, Serialize};

    #[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
    struct Foo {
        size: Size,
    }

    let json = r#"{"size": 42}"#;
    let foo: Foo = serde_json::from_str(json).unwrap();
    assert_eq!(
        foo,
        Foo {
            size: Size::from_bytes(42)
        }
    );
}

#[test]
fn test_deserialize_f64() {
    use serde::{Deserialize, Serialize};

    #[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
    struct Foo {
        size: Size,
    }

    let json = r#"{"size": 42.00}"#;
    let foo: Foo = serde_json::from_str(json).unwrap();
    assert_eq!(
        foo,
        Foo {
            size: Size::from_bytes(42)
        }
    );
}

#[test]
fn test_deserialize_overflow() {
    use serde::{Deserialize, Serialize};

    #[derive(Serialize, Deserialize, PartialEq, Eq, Debug)]
    struct Foo {
        size: Size,
    }

    let json = r#"{"size": 2.99792458e118}"#;
    let foo: Result<Foo, _> = serde_json::from_str(json);
    assert!(foo.is_err());
    let msg = foo.unwrap_err().to_string();
    assert!(msg.contains("out of range"));
}