Zillowe Docs - Custom Patch Formats

One of the unique features of zbsdiff is the ability to decouple the diffing engine from the patch storage format. This is achieved through the PatchWriter and PatchReader traits.

PatchWriter

Implement the PatchWriter trait to define how patch instructions and data are stored.

use zbsdiff::{Control, PatchWriter};

pub struct MyCustomWriter {
    // ... your storage (e.g. a database handle, custom compressor) ...
}

impl PatchWriter for MyCustomWriter {
    fn write_control(&mut self, ctrl: Control) -> std::io::Result<()> {
        // ... store control instruction ...
        Ok(())
    }

    fn write_delta(&mut self, delta: &[u8]) -> std::io::Result<()> {
        // ... store differential data ...
        Ok(())
    }

    fn write_extra(&mut self, extra: &[u8]) -> std::io::Result<()> {
        // ... store extra data ...
        Ok(())
    }

    fn finish(self) -> std::io::Result<u64> {
        // ... finalization ...
        Ok(0)
    }
}

Use it with Bsdiff::compare_with:

let writer = MyCustomWriter::new();
bsdiff.compare_with(writer)?;

PatchReader

Similarly, implement PatchReader to define how to retrieve patch data.

use zbsdiff::{Control, PatchReader};

impl PatchReader for MyCustomReader {
    fn target_size(&self) -> u64 { /* ... */ }
    fn read_control(&mut self) -> std::io::Result<Option<Control>> { /* ... */ }
    fn read_delta(&mut self, buf: &mut [u8]) -> std::io::Result<()> { /* ... */ }
    fn read_extra(&mut self, buf: &mut [u8]) -> std::io::Result<()> { /* ... */ }
}

Use it with Bspatch::apply_with:

let reader = MyCustomReader::new();
patcher.apply_with(reader, source, target)?;

Custom Patch Formats

PatchWriter

PatchReader

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