float-pigment-consistent-bincode 0.9.0

use alloc::vec::Vec;
use byteorder::ByteOrder;

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct Error {
    kind: ErrorKind,
}

impl Error {
    pub fn new(kind: ErrorKind) -> Self {
        Self { kind }
    }

    pub fn kind(&self) -> ErrorKind {
        self.kind
    }

    fn is_interrupted(&self) -> bool {
        match self.kind {
            ErrorKind::Unknown => false,
            ErrorKind::UnexpectedEof => true,
        }
    }
}

impl core::fmt::Display for Error {
    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
        f.write_str(match self.kind {
            ErrorKind::Unknown => "I/O Error",
            ErrorKind::UnexpectedEof => "Unexpected EOF",
        })
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ErrorKind {
    Unknown,
    UnexpectedEof,
}

impl From<ErrorKind> for Error {
    fn from(kind: ErrorKind) -> Self {
        Self { kind }
    }
}

impl serde::de::StdError for Error {}

pub type Result<T> = core::result::Result<T, Error>;

pub trait Read {
    fn read(&mut self, buf: &mut [u8]) -> Result<usize>;

    fn read_exact(&mut self, mut buf: &mut [u8]) -> Result<()> {
        while !buf.is_empty() {
            match self.read(buf) {
                Ok(0) => break,
                Ok(n) => {
                    buf = &mut buf[n..];
                }
                Err(ref e) if e.is_interrupted() => {}
                Err(e) => return Err(e),
            }
        }
        if !buf.is_empty() {
            Err(Error::new(ErrorKind::UnexpectedEof))
        } else {
            Ok(())
        }
    }

    fn read_u8(&mut self) -> Result<u8> {
        let mut buf = [0; 1];
        self.read_exact(&mut buf)?;
        Ok(buf[0])
    }

    fn read_u16<T: ByteOrder + 'static>(&mut self) -> Result<u16> {
        let mut buf = [0; 2];
        self.read_exact(&mut buf)?;
        Ok(T::read_u16(&buf))
    }

    fn read_u32<T: ByteOrder + 'static>(&mut self) -> Result<u32> {
        let mut buf = [0; 4];
        self.read_exact(&mut buf)?;
        Ok(T::read_u32(&buf))
    }

    fn read_u64<T: ByteOrder + 'static>(&mut self) -> Result<u64> {
        let mut buf = [0; 8];
        self.read_exact(&mut buf)?;
        Ok(T::read_u64(&buf))
    }

    fn read_u128<T: ByteOrder + 'static>(&mut self) -> Result<u128> {
        let mut buf = [0; 16];
        self.read_exact(&mut buf)?;
        Ok(T::read_u128(&buf))
    }

    fn read_f32<T: ByteOrder + 'static>(&mut self) -> Result<f32> {
        let mut buf = [0; 4];
        self.read_exact(&mut buf)?;
        Ok(T::read_f32(&buf))
    }

    fn read_f64<T: ByteOrder + 'static>(&mut self) -> Result<f64> {
        let mut buf = [0; 8];
        self.read_exact(&mut buf)?;
        Ok(T::read_f64(&buf))
    }
}

impl Read for &[u8] {
    #[inline]
    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
        let amt = core::cmp::min(buf.len(), self.len());
        let (a, b) = self.split_at(amt);

        // First check if the amount of bytes we want to read is small:
        // `copy_from_slice` will generally expand to a call to `memcpy`, and
        // for a single byte the overhead is significant.
        if amt == 1 {
            buf[0] = a[0];
        } else {
            buf[..amt].copy_from_slice(a);
        }

        *self = b;
        Ok(amt)
    }
}

impl<R: Read + ?Sized> Read for &mut R {
    fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
        (**self).read(buf)
    }
}

pub trait Write {
    fn write(&mut self, buf: &[u8]) -> Result<usize>;

    fn write_all(&mut self, mut buf: &[u8]) -> Result<()> {
        while !buf.is_empty() {
            match self.write(buf) {
                Ok(0) => {
                    return Err(ErrorKind::Unknown.into());
                }
                Ok(n) => buf = &buf[n..],
                Err(ref e) if e.is_interrupted() => {}
                Err(e) => return Err(e),
            }
        }
        Ok(())
    }

    fn write_u8(&mut self, n: u8) -> Result<()> {
        self.write_all(&[n])
    }

    fn write_u16<T: ByteOrder + 'static>(&mut self, n: u16) -> Result<()> {
        let mut buf = [0; 2];
        T::write_u16(&mut buf, n);
        self.write_all(&buf)
    }

    fn write_u32<T: ByteOrder + 'static>(&mut self, n: u32) -> Result<()> {
        let mut buf = [0; 4];
        T::write_u32(&mut buf, n);
        self.write_all(&buf)
    }

    fn write_u64<T: ByteOrder + 'static>(&mut self, n: u64) -> Result<()> {
        let mut buf = [0; 8];
        T::write_u64(&mut buf, n);
        self.write_all(&buf)
    }

    fn write_u128<T: ByteOrder + 'static>(&mut self, n: u128) -> Result<()> {
        let mut buf = [0; 16];
        T::write_u128(&mut buf, n);
        self.write_all(&buf)
    }

    fn write_f32<T: ByteOrder + 'static>(&mut self, n: f32) -> Result<()> {
        let mut buf = [0; 4];
        T::write_f32(&mut buf, n);
        self.write_all(&buf)
    }

    fn write_f64<T: ByteOrder + 'static>(&mut self, n: f64) -> Result<()> {
        let mut buf = [0; 8];
        T::write_f64(&mut buf, n);
        self.write_all(&buf)
    }
}

impl Write for &mut Vec<u8> {
    fn write(&mut self, buf: &[u8]) -> Result<usize> {
        self.extend(buf.iter());
        Ok(buf.len())
    }
}