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isgzipBuffer

Test if a value is a gzip buffer.

Installation

npm install @stdlib/assert-is-gzip-buffer

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
• If you are using Deno, visit the deno branch (see README for usage intructions).
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

var isgzipBuffer = require( '@stdlib/assert-is-gzip-buffer' );

isgzipBuffer( value )

Tests if a value is a gzip buffer.

var Uint8Array = require( '@stdlib/array-uint8' );

var buf = new Uint8Array( 20 );
buf[ 0 ] = 31;  // 0x1f => magic number
buf[ 1 ] = 139; // 0x8b
buf[ 2 ] = 8;   // 0x08 => compression method

var bool = isgzipBuffer( buf );
// returns true

bool = isgzipBuffer( [] );
// returns false

Notes

• A gzip buffer is defined as either a Node.js Buffer or Uint8Array which contains a 10-byte header, a body containing the compressed payload, and an 8-byte footer containing a CRC-32 checksum and the length of the original uncompressed data, modulo 2^32.
• This function only examines the 10-byte header to ensure the header includes the expected magic number and compression method. The function does not perform an integrity check.

Examples

var Float32Array = require( '@stdlib/array-float32' );
var Float64Array = require( '@stdlib/array-float64' );
var Int8Array = require( '@stdlib/array-int8' );
var Int16Array = require( '@stdlib/array-int16' );
var Int32Array = require( '@stdlib/array-int32' );
var Uint8Array = require( '@stdlib/array-uint8' );
var Uint8ClampedArray = require( '@stdlib/array-uint8c' );
var Uint16Array = require( '@stdlib/array-uint16' );
var Uint32Array = require( '@stdlib/array-uint32' );
var isgzipBuffer = require( '@stdlib/assert-is-gzip-buffer' );

var buf = new Uint8Array( 20 );
buf[ 0 ] = 31;  // 0x1f => magic number
buf[ 1 ] = 139; // 0x8b
buf[ 2 ] = 8;   // 0x08 => compression method

var bool = isgzipBuffer( buf );
// returns true

bool = isgzipBuffer( new Float32Array( 20 ) );
// returns false

bool = isgzipBuffer( new Int8Array( 20 ) );
// returns false

bool = isgzipBuffer( new Uint8Array( 20 ) );
// returns false

bool = isgzipBuffer( new Uint8ClampedArray( 20 ) );
// returns false

bool = isgzipBuffer( new Int16Array( 20 ) );
// returns false

bool = isgzipBuffer( new Uint16Array( 20 ) );
// returns false

bool = isgzipBuffer( new Int32Array( 20 ) );
// returns false

bool = isgzipBuffer( new Uint32Array( 20 ) );
// returns false

bool = isgzipBuffer( new Float64Array( 20 ) );
// returns false

bool = isgzipBuffer( new Array( 20 ) );
// returns false

bool = isgzipBuffer( {} );
// returns false

bool = isgzipBuffer( null );
// returns false

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See Also

• @stdlib/assert-is-buffer: test if a value is a Buffer object.
• @stdlib/assert-is-uint8array: test if a value is a Uint8Array.

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Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.