semdiff-differ-binary 0.4.2

Binary diff calculator and reporters for semdiff.
Documentation 
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use memmap2::Mmap;
use semdiff_core::fs::FileLeaf;
use semdiff_core::{Diff, DiffCalculator, MayUnsupported};
use similar::{ChangeTag, TextDiffConfig};
use std::convert;
use std::sync::Arc;

pub mod report_html;
pub mod report_json;
pub mod report_summary;

#[cfg(test)]
mod tests;

pub struct BinaryDiffReporter;

#[derive(Debug)]
pub struct BinaryDiff {
    equal: bool,
    expected: Arc<Mmap>,
    actual: Arc<Mmap>,
}

impl Diff for BinaryDiff {
    fn equal(&self) -> bool {
        self.equal
    }
}

impl BinaryDiff {
    fn expected(&self) -> &[u8] {
        &self.expected
    }

    fn actual(&self) -> &[u8] {
        &self.actual
    }

    fn changes(&self) -> similar::TextDiff<'_, '_, [u8]> {
        binary_diff_changes(&self.expected[..], &self.actual[..])
    }

    fn stat<'a>(changes: &'a similar::TextDiff<'a, 'a, [u8]>) -> ChangeStat {
        binary_change_stat(changes)
    }
}

fn binary_diff_changes<'a>(expected: &'a [u8], actual: &'a [u8]) -> similar::TextDiff<'a, 'a, [u8]> {
    TextDiffConfig::default()
        .algorithm(similar::Algorithm::Patience)
        .diff_chars(expected, actual)
}

fn binary_change_stat<'a>(changes: &'a similar::TextDiff<'a, 'a, [u8]>) -> ChangeStat {
    changes
        .iter_all_changes()
        .fold(ChangeStat::default(), |stat, change| match change.tag() {
            ChangeTag::Delete => stat.deleted(),
            ChangeTag::Insert => stat.added(),
            ChangeTag::Equal => stat,
        })
}

#[derive(Debug, Default)]
struct ChangeStat {
    added: usize,
    deleted: usize,
}

impl ChangeStat {
    fn added(self) -> ChangeStat {
        ChangeStat {
            added: self.added + 1,
            deleted: self.deleted,
        }
    }

    fn deleted(self) -> ChangeStat {
        ChangeStat {
            added: self.added,
            deleted: self.deleted + 1,
        }
    }
}

#[derive(Default)]
pub struct BinaryDiffCalculator;

impl DiffCalculator<FileLeaf> for BinaryDiffCalculator {
    type Error = convert::Infallible;
    type Diff = BinaryDiff;

    fn diff(
        &self,
        _name: &str,
        expected: FileLeaf,
        actual: FileLeaf,
    ) -> Result<MayUnsupported<Self::Diff>, Self::Error> {
        Ok(MayUnsupported::Ok(BinaryDiff {
            equal: <[u8] as PartialEq<[u8]>>::eq(&*expected.content, &*actual.content),
            expected: expected.content,
            actual: actual.content,
        }))
    }
}