| Message ID | 20231103162019.GB1470570@coredump.intra.peff.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | t: avoid perl's pack/unpack "Q" specifier | expand |
Jeff King <peff@peff.net> writes: > +# Some platforms' perl builds don't support 64-bit integers, and hence do not > +# allow packing/unpacking quadwords with "Q". The chunk format uses 64-bit file > +# offsets to support files of any size, but in practice our test suite will > +# only use small files. So we can fake it by asking for two 32-bit values and > +# discarding the first (most significant) one, which is equivalent as long as > +# it's just zero. > +sub unpack_quad { > + my $bytes = shift; > + my ($n1, $n2) = unpack("NN", $bytes); > + die "quad value exceeds 32 bits" if $n1; > + return $n2; > +}; Is this an unnecessary ';' at the end? > +sub pack_quad { > + my $n = shift; > + my $ret = pack("NN", 0, $n); > + # double check that our original $n did not exceed the 32-bit limit. > + # This is presumably impossible on a 32-bit system (which would have > + # truncated much earlier), but would still alert us on a 64-bit build > + # of a new test that would fail on a 32-bit build (though we'd > + # presumably see the die() from unpack_quad() in such a case). > + die "quad round-trip failed" if unpack_quad($ret) != $n; > + return $ret; > +} Nice. Both sub are done carefully. > # read until we find table-of-contents entry for chunk; > # note that we cheat a bit by assuming 4-byte alignment and > # that no ToC entry will accidentally look like a header. > # > # If we don't find the entry, copy() will hit EOF and exit > # (which should cause the caller to fail the test). > while (copy(4) ne $chunk) { } > -my $offset = unpack("Q>", copy(8)); > +my $offset = unpack_quad(copy(8)); > > # In clear mode, our length will change. So figure out > # the length by comparing to the offset of the next chunk, and > @@ -38,11 +62,11 @@ sub copy { > my $id; > do { > $id = copy(4); > - my $next = unpack("Q>", get(8)); > + my $next = unpack_quad(get(8)); > if (!defined $len) { > $len = $next - $offset; > } > - print pack("Q>", $next - $len + length($bytes)); > + print pack_quad($next - $len + length($bytes)); > } while (unpack("N", $id)); > }
On Sat, Nov 04, 2023 at 10:47:30AM +0900, Junio C Hamano wrote: > > +sub unpack_quad { > > + my $bytes = shift; > > + my ($n1, $n2) = unpack("NN", $bytes); > > + die "quad value exceeds 32 bits" if $n1; > > + return $n2; > > +}; > > Is this an unnecessary ';' at the end? Oops, yes. I'm not sure how that snuck in there. (It is not breaking anything, but if you were to remove it while applying, I would be very happy). -Peff
diff --git a/t/lib-chunk/corrupt-chunk-file.pl b/t/lib-chunk/corrupt-chunk-file.pl index cd6d386fef..b024bbdcb5 100644 --- a/t/lib-chunk/corrupt-chunk-file.pl +++ b/t/lib-chunk/corrupt-chunk-file.pl @@ -21,14 +21,38 @@ sub copy { return $buf; } +# Some platforms' perl builds don't support 64-bit integers, and hence do not +# allow packing/unpacking quadwords with "Q". The chunk format uses 64-bit file +# offsets to support files of any size, but in practice our test suite will +# only use small files. So we can fake it by asking for two 32-bit values and +# discarding the first (most significant) one, which is equivalent as long as +# it's just zero. +sub unpack_quad { + my $bytes = shift; + my ($n1, $n2) = unpack("NN", $bytes); + die "quad value exceeds 32 bits" if $n1; + return $n2; +}; +sub pack_quad { + my $n = shift; + my $ret = pack("NN", 0, $n); + # double check that our original $n did not exceed the 32-bit limit. + # This is presumably impossible on a 32-bit system (which would have + # truncated much earlier), but would still alert us on a 64-bit build + # of a new test that would fail on a 32-bit build (though we'd + # presumably see the die() from unpack_quad() in such a case). + die "quad round-trip failed" if unpack_quad($ret) != $n; + return $ret; +} + # read until we find table-of-contents entry for chunk; # note that we cheat a bit by assuming 4-byte alignment and # that no ToC entry will accidentally look like a header. # # If we don't find the entry, copy() will hit EOF and exit # (which should cause the caller to fail the test). while (copy(4) ne $chunk) { } -my $offset = unpack("Q>", copy(8)); +my $offset = unpack_quad(copy(8)); # In clear mode, our length will change. So figure out # the length by comparing to the offset of the next chunk, and @@ -38,11 +62,11 @@ sub copy { my $id; do { $id = copy(4); - my $next = unpack("Q>", get(8)); + my $next = unpack_quad(get(8)); if (!defined $len) { $len = $next - $offset; } - print pack("Q>", $next - $len + length($bytes)); + print pack_quad($next - $len + length($bytes)); } while (unpack("N", $id)); }