Struct Mmap

pub struct Mmap {
    pub size: u64,
    /* private fields */
}

A struct that represents a memory-mapped file.

Fields

size: u64

Implementations

impl Mmap

pub fn new(path: &Path) -> Result<Self, MmapError>

Creates a new Mmap instance by opening the file at the given path.

Arguments

• path - The path to the file to be memory-mapped.

Returns

A Result containing the Mmap instance or a MmapError if the operation fails.

Errors

This function may return the following errors:

• ErrFdNotAvail: The file descriptor is not available for mapping.
• ErrInvalidFd: The file descriptor is invalid.
• ErrUnaligned: The mapping is not properly aligned.
• ErrNoMapSupport: The file system does not support memory mapping.
• ErrNoMem: There is not enough memory available to complete the operation.
• ErrUnknown(code): An unknown error occurred with the given OS error code.

pub fn append(&mut self, data: &[u8]) -> Result<(), Error>

Appends the given data to the end of the memory-mapped file.

Arguments

• data - The data to be appended to the file.

Returns

A Result containing the unit type (()) or an io::Error if the operation fails.

pub fn append_with<F>(&mut self, len: usize, writer: F) -> Result<(), Error>

where F: FnOnce(&mut [u8]),

Appends data to the end of the memory-mapped file using a custom writer function.

Arguments

• len - The length of the data to be appended.
• writer - A closure that writes the data to the file.

Returns

A Result containing the unit type (()) or an io::Error if the operation fails.

pub fn overwrite(&self, offset: usize, data: &[u8]) -> Result<(), Error>

Overwrites the data at the specified offset in the memory-mapped file.

Arguments

• offset - The offset in the file where the data should be overwritten.
• data - The data to be written.

Returns

A Result containing the unit type (()) or an io::Error if the operation fails.

pub fn overwrite_with<F>( &self, offset: usize, len: usize, writer: F, ) -> Result<(), Error>

where F: FnOnce(&mut [u8]),

Overwrites data in the memory-mapped file using a custom writer function.

Arguments

• offset - The offset in the file where the data should be overwritten.
• len - The length of the data to be written.
• writer - A closure that writes the data to the file.

Returns

A Result containing the unit type (()) or an io::Error if the operation fails.

pub fn drop_from_tail(&mut self, len: usize) -> Result<(), Error>

Removes the specified amount of data from the end of the memory-mapped file by truncating the file.

Arguments

• len - The amount of data to be removed from the end of the file.

Returns

A Result containing the unit type (()) or an io::Error if the operation fails.

pub fn read(&self, offset: usize, len: usize) -> Result<Vec<u8>, Error>

Reads data from the memory-mapped file at the specified offset.

Arguments

• offset - The offset in the file where the data should be read from.
• buf - The buffer to store the read data.

Returns

A Result containing the number of bytes read or an io::Error if the operation fails.

pub fn read_with<F>( &self, offset: usize, len: usize, reader: F, ) -> Result<(), Error>

where F: FnOnce(&[u8]),

Reads data from the memory-mapped file at the specified offset using a custom reader function.

Arguments

• offset - The offset in the file where the data should be read from.
• len - The length of the data to be read.
• reader - A closure that reads the data from the file.

Returns

A Result containing the number of bytes read or an io::Error if the operation fails.