embedded-storage-inmemory 0.1.1

An in-memory implementation of embedded-storage
Documentation 
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#![allow(unused)]

use core::ops::{Bound, Range, RangeBounds};

use embedded_storage::nor_flash::{ErrorType, NorFlash, NorFlashError, NorFlashErrorKind, ReadNorFlash};
#[cfg(feature = "nightly")]
use embedded_storage_async::nor_flash::{NorFlash as AsyncNorFlash, ReadNorFlash as AsyncReadNorFlash};

pub struct MemFlash<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> {
    pub mem: [u8; SIZE],
}

#[derive(Debug)]
pub struct MemFlashError;

impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE> {
    pub const fn new(fill: u8) -> Self {
        Self { mem: [fill; SIZE] }
    }

    fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), MemFlashError> {
        let len = bytes.len();
        bytes.copy_from_slice(&self.mem[offset as usize..offset as usize + len]);
        Ok(())
    }

    fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), MemFlashError> {
        let offset = offset as usize;
        assert!(bytes.len() % WRITE_SIZE == 0);
        assert!(offset % WRITE_SIZE == 0);
        assert!(offset + bytes.len() <= SIZE);

        for ((offset, mem_byte), new_byte) in self.mem.iter_mut().enumerate().skip(offset).take(bytes.len()).zip(bytes) {
            assert_eq!(0xFF, *mem_byte, "Offset {} is not erased", offset);
            *mem_byte = *new_byte;
        }

        Ok(())
    }

    fn erase(&mut self, from: u32, to: u32) -> Result<(), MemFlashError> {
        let from = from as usize;
        let to = to as usize;
        assert!(from % ERASE_SIZE == 0);
        assert!(to % ERASE_SIZE == 0, "To: {}, erase size: {}", to, ERASE_SIZE);
        for i in from..to {
            self.mem[i] = 0xFF;
        }
        Ok(())
    }

    pub fn program(&mut self, offset: u32, bytes: &[u8]) -> Result<(), MemFlashError> {
        let offset = offset as usize;
        assert!(bytes.len() % WRITE_SIZE == 0);
        assert!(offset % WRITE_SIZE == 0);
        assert!(offset + bytes.len() <= SIZE);

        self.mem[offset..offset + bytes.len()].copy_from_slice(bytes);

        Ok(())
    }
}

impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> Default for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE> {
    fn default() -> Self {
        Self::new(0xFF)
    }
}

impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> ErrorType for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE> {
    type Error = MemFlashError;
}

impl NorFlashError for MemFlashError {
    fn kind(&self) -> NorFlashErrorKind {
        NorFlashErrorKind::Other
    }
}

impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> ReadNorFlash
    for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
{
    const READ_SIZE: usize = 1;

    fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Self::Error> {
        self.read(offset, bytes)
    }

    fn capacity(&self) -> usize {
        SIZE
    }
}

impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> NorFlash for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE> {
    const WRITE_SIZE: usize = WRITE_SIZE;
    const ERASE_SIZE: usize = ERASE_SIZE;

    fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Self::Error> {
        self.write(offset, bytes)
    }

    fn erase(&mut self, from: u32, to: u32) -> Result<(), Self::Error> {
        self.erase(from, to)
    }
}

#[cfg(feature = "nightly")]
impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> AsyncReadNorFlash
    for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
{
    const READ_SIZE: usize = 1;

    async fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Self::Error> {
        self.read(offset, bytes)
    }

    fn capacity(&self) -> usize {
        SIZE
    }
}

#[cfg(feature = "nightly")]
impl<const SIZE: usize, const ERASE_SIZE: usize, const WRITE_SIZE: usize> AsyncNorFlash
    for MemFlash<SIZE, ERASE_SIZE, WRITE_SIZE>
{
    const WRITE_SIZE: usize = WRITE_SIZE;
    const ERASE_SIZE: usize = ERASE_SIZE;

    async fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Self::Error> {
        self.write(offset, bytes)
    }

    async fn erase(&mut self, from: u32, to: u32) -> Result<(), Self::Error> {
        self.erase(from, to)
    }
}

#[cfg(test)]
mod tests {
    use crate::MemFlash;

    #[test]
    fn test_write() {
        let mut flash = MemFlash::<1024, 4, 1>::new(0xFF);
        flash.erase(0, 1024).unwrap();
        flash.write(512, b"hello").unwrap();

        let mut rx = [0; 5];
        flash.read(512, &mut rx).unwrap();
        assert_eq!(&rx, b"hello");
    }
}