Given a m-length pattern and n-length data, and σ-length alphabet ( σ = 256 ):
$ npm install bop [-g]
var Bop = ;
$cd bop/$npm test
to execute a single test file simply do:
$ node test/file-name.js
$ cd bop/$ npm run bench
Create an instance, using a pattern.
// orBuffer pattern | String pattern
Arguments within  are optional.
// Change the pattern to search.Bop# : Buffer/** Count matches, optionally starting from a particular index (default* is 0). It returns an Array containing the number of matches, and the* remaining bytes*/Bop# : Array// Same as #count, but without counting overlapping sequencesBop# : Array/** Count matches, and the max distance found between 2 matches,* optionally starting from a particular index (default is 0).* It returns an Array containing:* - the number of matches* - the max distance found between 2 matches, -1 otherwise* - the distance from data index 0 to the first match, -1 otherwise* - the distance from the end of the last match to the end of data,* -1 otherwise** NOTE: if 0 or only 1 occurrence was found, the max distance will* be -1 and then the resulting array will be respectvely:* - [0, -1, -1, -1 ]* - [1, -1, .., .. ]*/Bop# : Array// same as #dist, but without counting overlapping sequencesBop# : Array/** Collect all indexes of pattern occurrences.** As options you can:** - start parsing from a particular index* - limit the number of results to parse* - fill your array with resulting indexes.** NOTE: use Buffers when possible (faster).**/Bop# : Array/** Strict parse, it's the same as parse, without collecting* any overlapping sequences.** Example with CRLF sequence:** - bop pattern is set to: "\r\n\r\n" (CR LF CR LF)* - data to parse is: "\r\n\r\n\r\n\r\n\r\n\r\n" (CR LF CR LF CR LF CR LF )** - with Bop.parse( data ) we get 3 indexes as results: [0, 2, 4]** 0 1 2 3 4 5 6 7* -----------------------* p: CR LF CR LF* d: CR LF CR LF CR LF CR LF** p: ----> CR LF CR LF* d: CR LF CR LF CR LF CR LF** p: ----------> CR LF CR LF* d: CR LF CR LF CR LF CR LF** - with Bop.sparse( data ) we get only 2 results: [0, 4]** 0 1 2 3 4 5 6 7* -----------------------* p: CR LF CR LF* d: CR LF CR LF CR LF CR LF** p: ----------> CR LF CR LF* d: CR LF CR LF CR LF CR LF**/Bop# : Array
var Bop =pattern = 'hellofolks\r\n'somedata = 'hehehe' + pattern +'eheheh' + patternbop =// parse data from beginningresults = bop;
Parser uses 3 Buffers 256-bytes long to build shifting tables, then:
- Pattern parsing / table creation space and time complexity is O(σ).
- Very low memory footprint.
- Ultra fast to preprocess pattern ( = tables creation ).
$ node bench/small-pattern-data-rate
for default it:
- uses a pattern string of 57 bytes/chars.
- builds a data buffer of 700 MB in memory.
- uses a redundancy/distance factor for pattern strings equal to 2. The bigger the value, the lesser are occurrences of pattern string into the text buffer.
# with [testBufferSizeInMB] [distanceFactor] [aStringPattern]$ node bench/small-pattern-data-rate.js 700 4 "that'sallfolks"
Parser uses 3 arrays to build shifting tables for big patterns, then:
- there will be an high memory consumption, due to the use of arrays.
- it will take a long time to preprocess pattern ( = tables creation ).
$ node bench/big-pattern-data-rate
- it uses a very big pattern ( 20 MBytes ).
- it builds a data buffer of 300 MBytes, copying the same pattern 12 times.
See bench dir.
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