vbatts/path-packer-c
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
path-packer-c/ALGORITHM.md
James Bowes 17397ca0c2 Add start of algorithm file
2012-08-22 11:37:32 -03:00

5.1 KiB
Raw Blame History

PACKING ALGORITHM

Begin with a list of content set paths: ''' /content/dist/rhel/$releasever/$basearch/os /content/dist/rhel/$releasever/$basearch/debug /content/dist/rhel/$releasever/$basearch/source/SRPMS /content/dist/jboss/source /content/beta/rhel/$releasever/$basearch/os /content/beta/rhel/$releasever/$basearch/debug /content/beta/rhel/$releasever/$basearch/source/SRPMS '''

Create a prefix tree out of the paths, where each node in the tree contains the names of its children, rather than the children containing its own name:

''' +-------+ +------+ | | | | |-------+ |------| |content+--+-------+ |source+-+---+ +-------+ | | +------+ | | |-------| | |---| |dist +--------+-------+ | +---+ +--+beta | | | | | +-------+ |-------| | | |jboss +--+ +-------+ |rhel +--+ | | +-------+ | |-------| | |rhel +--+-----------+ +-----------+ +-------+ | | | | |-----------| |-----------| +----------+$releasever| |$releasever+--+ | +-----------+ +-----------+ | | | +---------+ +---------+ | | | | |---------| |---------| |$basearch+--+ +--+$basearch| +---+ +---------+ | | +---------+ | | | | |---| +--------+ +-------+ +---+ | | | | | |--------| |-------| | +---+--------+os | |os +---------+ | | +--+debug | |debug +-----------+---+ |---| | |source +--+ |source +--+ | | +---+ | +--------+ | +-------+ | |---| | | | +---+ +---+ +------+ | | | | | +-----+ |---| |------| | | +---+ +--+SRPMS | |-----| | +------+ |SRPMS+--+---+ | +-----+ | | +---+ |---| | | +---+ |---| +---+ '''

This eliminates the duplication in the prefixes of our paths. We now only have one instance of the word "content", for example. We now find any duplicate subtrees, remove the duplicate, and point all references from the duplicate to the original:

''' +-------+ +------+ | | | | |-------+ |------| |content+--+-------+ |source+-+ +-------+ | | +------+ | |-------| | | |dist +--------+-------+ | | +--+beta | | | | | | +-------+ |-------| | | | |jboss +--+ | +-------+-------------------+rhel | | | | +-------+ | |-------| | |rhel +--+-----------+ | +-------+ | | | |-----------| | +----------+$releasever| | | +-----------+ | | | +---------+ | | | | |---------| | |$basearch+--+ | +---------+ | | | | +--------+ | | | | |--------| | +-------+os | | | +--+debug | | | | |source +--+ | | | +--------+ | | | | | | | | +------+ | | +-------+ | | | | | |------| | | | +--+SRPMS | | | | | +------+ | | | | | +------------+---+-------------------------+ | |
|---| +---+ '''