APT Cache File Format

Abstract

This document describes the complete implementation and format of the APT Cache file. The APT Cache file is a way for APT to parse and store a large number of package files for display in the UI. It's primary design goal is to make display of a single package in the tree very fast by pre-linking important things like dependencies and provides. The specification doubles as documentation for one of the in-memory structures used by the package library and the APT GUI.

Copyright Notice

Copyright © Jason Gunthorpe, 1997-1998.

APT and this document are free software; you can redistribute them and/or modify them under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

For more details, on Debian GNU/Linux systems, see the file /usr/share/common-licenses/GPL for the full license.

Contents

• 1 Introduction
• 1.1 Purpose
• 2 Structures
• 2.1 Header
• 2.2 Package
• 2.3 PackageFile
• 2.4 Version
• 2.5 Dependency
• 2.6 Provides
• 2.7 VerFile
• 2.8 StringItem
• 2.9 StringTable
• 2.10 Defines
• 3 Notes on the Generator
• 4 Future Directions

APT Cache File Format