Results 1 to 8 of 8

Thread: qc - compressor

  1. #1
    Member
    Join Date
    Aug 2008
    Location
    Planet Earth
    Posts
    1,026
    Thanks
    103
    Thanked 410 Times in 285 Posts

    ksc - compressor

    ksc - keyword shuffle compressor build during compression dynamic a dictionary with selected 1,2,3 or 4 bytes as keyword size and store pointers to each unique keyword. New and existing keywords are moved to the front. Pointers and keyword dictionary are stored as output, where pointers are stored in two ways, or half the maximal possible pointer bit length or the maximal pointer bit length. By decompression the keyword dictionary and pointers are read in memory, the output file is written backwards and with reverse shuffle of keywords.

    It run under Windows as GUI only, mode 32 and 64-bit and need Framework 4.5 or higher.

    Compression is between 10-40% at not binary files.
    Speed maximal 500 KB/s during compression and 3250 KB/s during decompression.
    Memory usage is low with compression and high with decompression round 1.3 times output file size.

    Download
    http://www.metacompressor.com/download/ksc.zip

    It's possible to decompress without reading pointers first in memory by changing the format a little and reading the input file backwards.
    Last edited by Sportman; 15th February 2014 at 14:05. Reason: Renamed application (maybe it's possible to rename thread title)

  2. #2
    Member
    Join Date
    May 2012
    Location
    United States
    Posts
    342
    Thanks
    197
    Thanked 58 Times in 42 Posts
    Is it possible to get KSC.EXE in x86/32-bit?

    Thanks.

  3. #3
    Member
    Join Date
    Aug 2008
    Location
    Planet Earth
    Posts
    1,026
    Thanks
    103
    Thanked 410 Times in 285 Posts
    Quote Originally Posted by comp1 View Post
    Is it possible to get KSC.EXE in x86/32-bit?
    Strange enough even forced 32-bit versions do not work under Windows 32-bit, so I switched back to a much older VS version with only support for older Framework versions to compile a 32-bit version:

    32-bit and need Framework 3.5 or higher.

    Download
    http://www.metacompressor.com/download/ksc-32bit.zip

  4. #4
    Member
    Join Date
    Aug 2008
    Location
    Planet Earth
    Posts
    1,026
    Thanks
    103
    Thanked 410 Times in 285 Posts
    I added command line support (GUI still possible):

    ksc c 1 in out (1 can be also 2,3 or 4 as keyword byte length)
    ksc d in out

    64-bit and need Framework 4.5 or higher:

    Download
    http://www.metacompressor.com/download/ksc.zip

    32-bit and need Framework 3.5 or higher:

    Download
    http://www.metacompressor.com/download/ksc-32bit.zip

    Framework 4.5 version is 15-20% faster.

  5. #5
    Member
    Join Date
    Sep 2011
    Location
    uk
    Posts
    239
    Thanks
    189
    Thanked 17 Times in 12 Posts
    Thanks for 32 bit - but when I download with chrome using the link above it gives red warning & says it shouldn't be downloaded. Is there something about it that causes this? Name of .zip or .exe? Contents? Anyone else see this?

    John

  6. #6
    Member
    Join Date
    Aug 2008
    Location
    Planet Earth
    Posts
    1,026
    Thanks
    103
    Thanked 410 Times in 285 Posts
    Quote Originally Posted by avitar View Post
    Is there something about it that causes this? Name of .zip or .exe? Contents?
    Ask Google

    I wrote the source code and check every .exe/.zip with good virus scanner before upload, so all my posted files are clean. You can always test websites or files before download or after download before starting at https://www.virustotal.com (also owned by Google).

  7. #7
    Expert
    Matt Mahoney's Avatar
    Join Date
    May 2008
    Location
    Melbourne, Florida, USA
    Posts
    3,257
    Thanks
    307
    Thanked 797 Times in 489 Posts
    Chrome often warns me when I download a zip containing an .exe file. I just ignore it. For some reason it says zpaq is OK.

  8. #8
    Expert
    Matt Mahoney's Avatar
    Join Date
    May 2008
    Location
    Melbourne, Florida, USA
    Posts
    3,257
    Thanks
    307
    Thanked 797 Times in 489 Posts
    I added ksc to LTCB. http://mattmahoney.net/dc/text.html#5805

    This looks like a symbol ranking algorithm with a very large alphabet (up to 2^32). You might be interested in other symbol ranking algorithms like srank, sr2, sr3, which are very fast with fairly good compression. The idea is to use a one character alphabet but have multiple move-to-front queues selected by a context or context hash. This is faster because the queue is small (3 bytes for sr2, sr3) and any symbol not found in the queue is either coded literally (sr2, sr3) or from a secondary queue with an index and move-about-halfway-to-front queue for speed (srank). It's not necessary to decode in reverse order or transmit a dictionary because the decompresser maintains an exact copy of the queue from the decompressed output using the same code as the compressor.

  9. Thanks:

    Sportman (10th March 2014)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •