Struct ChunkWriter 

pub struct ChunkWriter<W> { /* private fields */ }

This struct is used to write out chunks to a file.

Implementations

impl<W: Write + Seek> ChunkWriter<W>

pub fn id(&self) -> ChunkId

Returns the chunk ID

pub fn offset(&self) -> u64

Returns the offset at which this chunk is written in the underlying writer. Similar to Chunk::offset, this is is usually 0 for child chunks, since the use a ContentWriter, which only sees the children data.

pub fn content_len(&self) -> u32

Returns the current length of the contents.

pub fn children_len(&self) -> u32

Returns the current length of the children data. This is the total number of bytes written for children chunks.

pub fn content_writer<'w, F: FnMut(&mut ContentWriter<&'w mut W>) -> Result<(), WriteError>>( &'w mut self, f: F, ) -> Result<(), WriteError>

Writes data to the chunks content.

Note, that this must be called before any calls to child_writer.

Example

use std::io::Write;

chunk_writer.content_writer(|writer| {
    // `writer` implements `std::io::Write + std::io::Seek`.
    writer.write_all(b"Hello World")?;
    Ok(())
})

Panics

Panics, if children have been written already.

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

Writes the given slice to the chunk’s data.

pub fn child_writer<'w, F: FnMut(&mut ChildWriter<'w, W>) -> Result<(), WriteError>>( &'w mut self, chunk_id: ChunkId, f: F, ) -> Result<(), WriteError>

Writes children chunks to this chunk. Note, that after a child has been written to a chunk, you can’t write any more data to its contents.

Example

chunk_writer.child_writer(ChunkId::Main, |child_writer| {
    // `child_writer` is just another `ChunkWriter`.
    child_writer.write_content(b"Hello World")?;
    Ok(())
})

pub fn child_content_writer<'w, F: FnMut(&mut ContentWriter<&mut ContentWriter<&'w mut W>>) -> Result<(), WriteError>>( &'w mut self, chunk_id: ChunkId, f: F, ) -> Result<(), WriteError>

Short-hand to opening and child-writer and then a content-writer to that child. Useful, if you want to write a child with only content data.

Trait Implementations

impl<W: Debug> Debug for ChunkWriter<W>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.