pkgTagFile::Jump: Use lookback buffer to rejump to current position

If we get called twice with the same offset, our d->Start and d->iOffset
will already point at the offset for the next section. But since we have
the start of the last parsed section still in the buffer, just make sure
to always go back to the start first.

Closes: #1067440

1 files changed, 5 insertions, 0 deletions

diff --git a/apt-pkg/tagfile.cc b/apt-pkg/tagfile.cc
index 8f323bb5a..95ae4a483 100644
--- a/apt-pkg/tagfile.cc
+++ b/apt-pkg/tagfile.cc
@@ -431,6 +431,11 @@ bool pkgTagFile::Fill()
    that is there */
 bool pkgTagFile::Jump(pkgTagSection &Tag,unsigned long long Offset)
 {
+   // Head back to the start of the buffer, in case we get called for the same section
+   // again (d->Start will point to next section already)
+   d->iOffset -= d->Start - d->Buffer;
+   d->Start = d->Buffer;
+
    if ((d->Flags & pkgTagFile::SUPPORT_COMMENTS) == 0 &&
    // We are within a buffer space of the next hit..
 	 Offset >= d->iOffset && d->iOffset + (d->End - d->Start) > Offset)