Jeff King <peff@xxxxxxxx> 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));
> }
