streamsearch

Description
===========

streamsearch is a module for node.js that allows searching a stream using the Boyer-Moore-Horspool algorithm.

This module is based heavily on the Streaming Boyer-Moore-Horspool C++ implementation by Hongli Lai here.

Requirements
============

* node.js -- v10.0.0 or newer

Installation
============

npm install streamsearch

Example
=======

``js
const { inspect } = require('util');

const StreamSearch = require('streamsearch');

const needle = Buffer.from('\r\n');
const ss = new StreamSearch(needle, (isMatch, data, start, end) => {
if (data)
console.log('data: ' + inspect(data.toString('latin1', start, end)));
if (isMatch)
console.log('match!');
});

const chunks = [
'foo',
' bar',
'\r',
'\n',
'baz, hello\r',
'\n world.',
'\r\n Node.JS rules!!\r\n\r\n',
];
for (const chunk of chunks)
ss.push(Buffer.from(chunk));

// output:
//
// data: 'foo'
// data: ' bar'
// match!
// data: 'baz, hello'
// match!
// data: ' world.'
// match!
// data: ' Node.JS rules!!'
// match!
// data: ''
// match!
`


API
===

Properties
----------

* maxMatches - < _integer_ > - The maximum number of matches. Defaults to Infinity.

* matches - < _integer_ > - The current match count.


Functions
---------

* (constructor)(< _mixed_ >needle, < _function_ >callback) - Creates and returns a new instance for searching for a _Buffer_ or _string_ needle. callback is called any time there is non-matching data and/or there is a needle match. callback will be called with the following arguments:

1. isMatch - _boolean_ - Indicates whether a match has been found

2. data - _mixed_ - If set, this contains data that did not match the needle.

3. start - _integer_ - The index in data where the non-matching data begins (inclusive).

4. end - _integer_ - The index in data where the non-matching data ends (exclusive).

5. isSafeData - _boolean_ - Indicates if it is safe to store a reference to data (e.g. as-is or via data.slice()) or not, as in some cases data may point to a Buffer whose contents change over time.

* destroy() - _(void)_ - Emits any last remaining unmatched data that may still be buffered and then resets internal state.

* push(< _Buffer_ >chunk) - _integer_ - Processes chunk, searching for a match. The return value is the last processed index in chunk` + 1.

* reset() - _(void)_ - Resets internal state. Useful for when you wish to start searching a new/different stream for example.