Initial version

Author: jhiesey

.gitignore

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+.DS_Store
+node_modules
+npm-debug.log
+.zuulrc

.travis.yml

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+language: node_js
+node_js:
+  - "4.1"

.zuul.yml

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+ui: tape
+browsers:
+  - name: chrome
+    version: 39..latest
+  - name: firefox
+    version: 34..latest
+  - name: safari
+    version: 5..latest
+  - name: ie
+    version: 10..latest
+  - name: opera
+    version: 11..latest
+  - name: iphone
+    version: 5.1..latest
+  - name: android
+    version: 4.0..latest

LICENSE

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+The MIT License
+
+Copyright (c) 2016 John Hiesey
+
+Permission is hereby granted, free of charge, 
+to any person obtaining a copy of this software and 
+associated documentation files (the "Software"), to 
+deal in the Software without restriction, including 
+without limitation the rights to use, copy, modify, 
+merge, publish, distribute, sublicense, and/or sell 
+copies of the Software, and to permit persons to whom 
+the Software is furnished to do so, 
+subject to the following conditions:
+
+The above copyright notice and this permission notice 
+shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR 
+ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

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+# to-arraybuffer [![Build Status](https://travis-ci.org/jhiesey/to-arraybuffer.svg?branch=master)](https://travis-ci.org/jhiesey/to-arraybuffer)
+
+[![Sauce Test Status](https://saucelabs.com/browser-matrix/to-arraybuffer.svg)](https://saucelabs.com/u/to-arraybuffer)
+
+Convert from a Buffer to an ArrayBuffer as fast as possible.
+
+Note that in some cases the returned ArrayBuffer is backed by the same memory as the original
+Buffer (but in other cases it is a copy), so **modifying the ArrayBuffer is not recommended**.
+
+This module is designed to work both in node.js and in all browsers with ArrayBuffer support
+when using [the Buffer implementation provided by Browserify](https://www.npmjs.com/package/buffer).
+
+## Usage
+
+``` js
+var toArrayBuffer = require('to-arraybuffer')
+
+var buffer = new Buffer(100)
+// Fill the buffer with some data
+
+var ab = toArrayBuffer(buffer)
+// `ab` now cotains the same data as `buffer`
+```
+
+## License
+
+MIT

index.js

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+var Buffer = require('buffer').Buffer
+
+module.exports = function (buf) {
+	// If the buffer is backed by a Uint8Array, a faster version will work
+	if (buf instanceof Uint8Array) {
+		// If the buffer isn't a subarray, return the underlying ArrayBuffer
+		if (buf.byteOffset === 0 && buf.byteLength === buf.buffer.byteLength) {
+			return buf.buffer
+		} else if (typeof buf.buffer.slice === 'function') {
+			// Otherwise we need to get a proper copy
+			return buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength)
+		}
+	}
+
+	if (Buffer.isBuffer(buf)) {
+		// This is the slow version that will work with any Buffer
+		// implementation (even in old browsers)
+		var arrayCopy = new Uint8Array(buf.length)
+		var len = buf.length
+		for (var i = 0; i < len; i++) {
+			arrayCopy[i] = buf[i]
+		}
+		return arrayCopy.buffer
+	} else {
+		throw new Error('Argument must be a Buffer')
+	}
+}

package.json

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+{
+  "name": "to-arraybuffer",
+  "version": "1.0.0",
+  "description": "Get an ArrayBuffer from a Buffer as fast as possible",
+  "main": "index.js",
+  "scripts": {
+    "test": "npm run test-node && ([ -n \"${TRAVIS_PULL_REQUEST}\" -a \"${TRAVIS_PULL_REQUEST}\" != 'false' ] || npm run test-browser)",
+    "test-node": "tape test.js",
+    "test-browser": "zuul --no-coverage -- test.js",
+    "test-browser-local": "zuul --local 8080 --no-coverage -- test.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/jhiesey/to-arraybuffer.git"
+  },
+  "keywords": [
+    "buffer",
+    "to",
+    "arraybuffer",
+    "fast",
+    "read",
+    "only"
+  ],
+  "author": "John Hiesey",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/jhiesey/to-arraybuffer/issues"
+  },
+  "homepage": "https://github.com/jhiesey/to-arraybuffer#readme",
+  "devDependencies": {
+    "tape": "^4.4.0",
+    "zuul": "^3.9.0"
+  }
+}

test.js

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+var Buffer = require('buffer').Buffer
+var test = require('tape')
+
+var toArrayBuffer = require('.')
+
+function elementsEqual (ab, buffer) {
+	var view = new Uint8Array(ab)
+	for (var i = 0; i < view.length; i++) {
+		if (view[i] !== buffer[i]) {
+			return false
+		}
+	}
+	return true
+}
+
+test('Basic behavior', function (t) {
+	var buf = new Buffer(10)
+	for (var i = 0; i < 10; i++) {
+		buf[i] = i
+	}
+
+	var ab = toArrayBuffer(buf)
+
+	t.equals(ab.byteLength, 10, 'correct length')
+	t.ok(elementsEqual(ab, buf), 'elements equal')
+	t.end()
+})
+
+test('Behavior when input is a subarray 1', function (t) {
+	var origBuf = new Buffer(10)
+	for (var i = 0; i < 10; i++) {
+		origBuf[i] = i
+	}
+	var buf = origBuf.slice(1)
+
+	var ab = toArrayBuffer(buf)
+
+	t.equals(ab.byteLength, 9, 'correct length')
+	t.ok(elementsEqual(ab, buf), 'elements equal')
+	t.notOk(ab === buf.buffer, 'the underlying ArrayBuffer is not returned when incorrect')
+	t.end()
+})
+
+test('Behavior when input is a subarray 2', function (t) {
+	var origBuf = new Buffer(10)
+	for (var i = 0; i < 10; i++) {
+		origBuf[i] = i
+	}
+	var buf = origBuf.slice(0, 9)
+
+	var ab = toArrayBuffer(buf)
+
+	t.equals(ab.byteLength, 9, 'correct length')
+	t.ok(elementsEqual(ab, buf), 'elements equal')
+	t.notOk(ab === buf.buffer, 'the underlying ArrayBuffer is not returned when incorrect')
+	t.end()
+})