mvcomp Activity
simple data compressing algorithm for constrained environments
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Activity for mvcomp
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Mateusz Viste committed [r61] on Code
minor reformatting and rewording
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use legacy hex notation for wider compatibility
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jumps are made explicitely short so the output code is the same with nasm -O0
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minor comments
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ECM: calculate maxbytesahead during first depack run, display (picked from https://hg.pushbx.org/ecm/mvcomp/rev/0cc061c18c01)
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ECM: allow empty unit parameter (picked from https://hg.pushbx.org/ecm/mvcomp/rev/04a4af663882)
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ECM: allow to specify different allocation unit, default 16 (picked from https://hg.pushbx.org/ecm/mvcomp/rev/5b599752225e)
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ECM: change rounding overflow differently (picked from https://hg.pushbx.org/ecm/mvcomp/rev/fae4318abace)
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ECM: fix typos (picked from https://hg.pushbx.org/ecm/mvcomp/rev/d49e7a66aeac)
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updated links
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20241010
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added a makefile target for releases
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added test for expected compression ratio
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merged testchk.sh with test.sh
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added a clear message about test result
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8086 assembly routine for mvpack depacking
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some words about in-place decompression
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ECM: imported from https://hg.pushbx.org/ecm/mvcomp/rev/338250570cff
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www update
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20241007
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basic sanity check on input stream
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empty files are considered to be an error
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removed dysfunctional file
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reworded documentation
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increased buffers, 5% speedup
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buffer sizes are properly calculated based on defines
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preserve const while casting
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x4 speedup
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never break an even-sized literal queue
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added a test file with NLS strings
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extend test to big file
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do not display differences, just tell if files are different
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less willing to break a literal queue of an even length, as such break is more expensive than breaking an uneven queue
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primitive test suite
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speed-up step 2: reduced the number of matches tested (33x faster than the original code)
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speed-up step 1: replace memcmp() by own implementation (3x faster)
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a suite of files for testing compression/decompression
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imported mvsize by ECM, from https://hg.pushbx.org/ecm/mvcomp/file/6ffb58fb1838/mvsize.c
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zero input produces an explicit message, avoids calculating a percent value on 0
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use memmove() instead of memcpy() because the rewind buffer usually overlaps with itself
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gcc compatibility
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updated link to reference implementation
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20241002
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operating on percentage points instead of % makes results look more favorable to mvcomp, and add a "scientific-like" sound to it
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ZIP comparison stands for small files only. on big files the ZIP advantage is more pronounced (up to 30%), likely because of its much wider backreference window
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mvcomp is able to compress files larger than 64K (up to size_t bytes)
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a back reference smaller than offset is perfectly valid, make compressor use it for RLE and self-duplicating strings
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title improved
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fixed link
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renamed tag
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20241001
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improved wording
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website
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fixed a fclose() that was too early
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minor fixes
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compiles
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mvcomp is the compressor
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improved documentation
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renamed mvcomp uncompressor to mvucomp
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to-be-tested implementation of the unpacker
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initial commit
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