> > + fn read_type(mut fobj: &File) -> Result<RecordType>
> > + {
> > + let mut tbuf = [0u8; 8];
> > + if let Err(e) = fobj.read_exact(&mut tbuf) {
> > + if e.kind() == ErrorKind::UnexpectedEof {
> > + return Ok(RecordType::Empty);
> > + } else {
> > + return Err(Error::ReadFile(e));
> > + }
> > + }
> > +
> > + /*
> > + * Safe because the layout of the trace record requires us to parse
> > + * the type first, and then there is a check on the validity of the
> > + * record type.
> > + */
> > + let raw_t =
> > + unsafe { std::mem::transmute::<[u8; 8], RecordRawType>(tbuf) };
>
> A safe alternative:
> https://doc.rust-lang.org/std/primitive.u64.html#method.from_ne_bytes?
Thanks! Will use it.
> > + match raw_t.rtype {
> > + RECORD_TYPE_MAPPING => Ok(RecordType::Mapping),
> > + RECORD_TYPE_EVENT => Ok(RecordType::Event),
> > + _ => Err(Error::UnknownRecType(raw_t.rtype)),
> > + }
> > + }
> > +}
[snip]
> > +{
> > + fn read_header(mut fobj: &File) -> Result<Self>
> > + {
> > + let mut raw_hdr = [0u8; 24];
> > + fobj.read_exact(&mut raw_hdr).map_err(Error::ReadFile)?;
> > +
> > + /*
> > + * Safe because the size of log header (struct LogHeader)
> > + * is 24 bytes, which is ensured by simple trace backend.
> > + */
> > + let hdr =
> > + unsafe { std::mem::transmute::<[u8; 24], LogHeader>(raw_hdr) };
>
> Or u64::from_ne_bytes() for each field.
Will do.
> > + Ok(hdr)
> > + }
> > +}
[snip]
> > +impl ReadHeader for RecordHeader
> > +{
> > + fn read_header(mut fobj: &File) -> Result<Self>
> > + {
> > + let mut raw_hdr = [0u8; 24];
> > + fobj.read_exact(&mut raw_hdr).map_err(Error::ReadFile)?;
> > +
> > + /*
> > + * Safe because the size of record header (struct RecordHeader)
> > + * is 24 bytes, which is ensured by simple trace backend.
> > + */
> > + let hdr: RecordHeader =
> > + unsafe { std::mem::transmute::<[u8; 24],
> > RecordHeader>(raw_hdr) };
>
> Or u64::from_ne_bytes() and u32::from_ne_bytes() for all fields.
Will do.
Thanks,
Zhao
