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Monorepo for Tangled
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12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758use crate::data;
pub(crate) const N32_SIZE: usize = std::mem::size_of::<u32>();
/// Parses the first 12 bytes of a pack file, returning the pack version as well as the number of objects contained in the pack.pub fn decode(data: &[u8; 12]) -> Result<(data::Version, u32), decode::Error> { let mut ofs = 0; if &data[ofs..ofs + b"PACK".len()] != b"PACK" { return Err(decode::Error::Corrupt( "Pack data type not recognized".into(), )); } ofs += N32_SIZE; let kind = match crate::read_u32(&data[ofs..ofs + N32_SIZE]) { 2 => data::Version::V2, 3 => data::Version::V3, v => return Err(decode::Error::UnsupportedVersion(v)), }; ofs += N32_SIZE; let num_objects = crate::read_u32(&data[ofs..ofs + N32_SIZE]);
Ok((kind, num_objects))}
/// Write a pack data header at `version` with `num_objects` and return a buffer.pub fn encode(version: data::Version, num_objects: u32) -> [u8; 12] { use crate::data::Version::*; let mut buf = [0u8; 12]; buf[..4].copy_from_slice(b"PACK"); buf[4..8].copy_from_slice( &match version { V2 => 2u32, V3 => 3, } .to_be_bytes()[..], ); buf[8..].copy_from_slice(&num_objects.to_be_bytes()[..]); buf}
///pub mod decode { /// Returned by [`decode()`][super::decode()]. #[derive(thiserror::Error, Debug)] #[allow(missing_docs)] pub enum Error { #[error("Could not open pack file at '{path}'")] Io { source: std::io::Error, path: std::path::PathBuf, }, #[error("{0}")] Corrupt(String), #[error("Unsupported pack version: {0}")] UnsupportedVersion(u32), }}