96 lines
2.6 KiB
Markdown
96 lines
2.6 KiB
Markdown
Description
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===========
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streamsearch is a module for [node.js](http://nodejs.org/) that allows searching a stream using the Boyer-Moore-Horspool algorithm.
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This module is based heavily on the Streaming Boyer-Moore-Horspool C++ implementation by Hongli Lai [here](https://github.com/FooBarWidget/boyer-moore-horspool).
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Requirements
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============
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* [node.js](http://nodejs.org/) -- v10.0.0 or newer
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Installation
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============
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npm install streamsearch
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Example
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=======
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```js
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const { inspect } = require('util');
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const StreamSearch = require('streamsearch');
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const needle = Buffer.from('\r\n');
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const ss = new StreamSearch(needle, (isMatch, data, start, end) => {
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if (data)
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console.log('data: ' + inspect(data.toString('latin1', start, end)));
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if (isMatch)
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console.log('match!');
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});
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const chunks = [
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'foo',
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' bar',
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'\r',
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'\n',
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'baz, hello\r',
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'\n world.',
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'\r\n Node.JS rules!!\r\n\r\n',
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];
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for (const chunk of chunks)
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ss.push(Buffer.from(chunk));
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// output:
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//
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// data: 'foo'
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// data: ' bar'
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// match!
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// data: 'baz, hello'
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// match!
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// data: ' world.'
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// match!
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// data: ' Node.JS rules!!'
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// match!
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// data: ''
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// match!
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```
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API
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===
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Properties
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----------
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* **maxMatches** - < _integer_ > - The maximum number of matches. Defaults to `Infinity`.
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* **matches** - < _integer_ > - The current match count.
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Functions
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---------
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* **(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:
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1. `isMatch` - _boolean_ - Indicates whether a match has been found
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2. `data` - _mixed_ - If set, this contains data that did not match the needle.
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3. `start` - _integer_ - The index in `data` where the non-matching data begins (inclusive).
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4. `end` - _integer_ - The index in `data` where the non-matching data ends (exclusive).
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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.
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* **destroy**() - _(void)_ - Emits any last remaining unmatched data that may still be buffered and then resets internal state.
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* **push**(< _Buffer_ >chunk) - _integer_ - Processes `chunk`, searching for a match. The return value is the last processed index in `chunk` + 1.
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* **reset**() - _(void)_ - Resets internal state. Useful for when you wish to start searching a new/different stream for example.
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