Bagas Sanjaya <bagasdotme@xxxxxxxxx> writes: > Document binary file patch formats that are different from text file > patch. > > Signed-off-by: Bagas Sanjaya <bagasdotme@xxxxxxxxx> > --- > Documentation/git-format-patch.txt | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt > index 247033f8fc..8de172b1f4 100644 > --- a/Documentation/git-format-patch.txt > +++ b/Documentation/git-format-patch.txt > @@ -725,6 +725,28 @@ diff format is described as below: > > include::diff-generate-patch.txt[] > > +Binary Files > +~~~~~~~~~~~~ > +For binary files, the diff format have some differences compared to text > +files: I do not think this is specific to 'format-patch'. If we need to describe 'git diff --binary', it should be done there, so that readers of "git diff --help" would also be able to learn the format. > +1. Object hashes in index header line (`index <hash>..<hash> <mode>`) s/Object hash/Object name/; > + are always given in full form, as binary patch is designed to be > + applied only to an exact copy of original file. This is to ensure > + that such patch don't apply to file with similar name but different > + hash. ... with similar but different object name. cf. Documentation/glossary-contents.txt tells you what "object name" is. > +2. There are additional extended header lines specific to binary files: > + > + GIT binary patch > + delta <bytes> > + literal <bytes> > + > +3. The diff body can be either delta or full (literal) content, > + whichever is the smallest size. It is encoded with base85 algorithm, > + and emitted in 64 characters each line. All but the last line in > + the body are prefixed with `z`. I do not think this is all that useful; it clutters the description for a reader who is not interested in reimplementing an encoder or a decoder from the document. And it is way too insufficient for a reader who wants to reimplement an encoder or a decoder. For example, - It does not say anything about what the delta is and how it is computed. - The 'z' is redundant; the more important is to say that the first byte signals how many bytes are on that line and it is a mere artifact that we cram up to 52 bytes on a line. - It does not say anything about how the binary patch ensures that it is reversible (i.e. can be given to "git apply -R"). Thanks.
