Add gzip detection to file sniffer

Author: codedread

CHANGELOG.md

@@ -7,6 +7,7 @@ All notable changes to this project will be documented in this file.
 ### Added
 
 - archive: Support DEFLATE in Zipper where JS implementations support it in CompressionStream.
+- file: Added detection of GZIP files.
 - io: Added a skip() method to BitStream to match ByteStream.
 
 ## [1.2.1] - 2024-01-19

file/sniffer.js

@@ -26,6 +26,7 @@ const fileSignatures = {
   'application/pdf': [[0x25, 0x50, 0x44, 0x46, 0x2d]], // '%PDF-'
 
   // Archive formats:
+  'application/gzip': [[0x1F, 0x8B]],
   'application/x-tar': [ // 'ustar'
     [0x75, 0x73, 0x74, 0x61, 0x72, 0x00, 0x30, 0x30],
     [0x75, 0x73, 0x74, 0x61, 0x72, 0x20, 0x20, 0x00],

media/media.js

@@ -3,7 +3,7 @@ console.warn(`This is not even an alpha-level API. Do not use.`);
 // A Container Format is a file that embeds multiple data streams into a single file.
 // Examples:
 //   - the ZIP family (ZIP, JAR, CBZ, EPUB, ODF, OOXML)
-//   - the ISO-BMFF family (MP4, HEVC, AVIF, MOV/QT, etc)
+//   - the ISO-BMFF family (MP4, HEVC, HEIC, AVIF, MOV/QT, etc)
 //   - the Matroska family (MKV, WebM)
 //   - the RIFF family (WAV, AVI, WebP)
 //   - the OGG family (OGV, OPUS)

tests/file-sniffer.spec.js

@@ -24,6 +24,7 @@ describe('bitjs.file.sniffer', () => {
   it('PNG', () => { sniffTest('image/png', [0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A, 0xFF]); });
   it('WebP', () => { sniffTest('image/webp', [0x52, 0x49, 0x46, 0x46, 0x01, 0x02, 0x03, 0x04, 0x57, 0x45, 0x42, 0x50, 0x81]); });
   it('ICO', () => { sniffTest('image/x-icon', [0x00, 0x00, 0x01, 0x00, 0x69])});
+  it('GZIP', () => { sniffTest('application/gzip', [0x1F, 0x8B, 0x08])});
   it('ZIP', () => { sniffTest('application/zip', [0x50, 0x4B, 0x03, 0x04, 0x20]); });
   it('ZIP_empty', () => { sniffTest('application/zip', [0x50, 0x4B, 0x05, 0x06, 0x20]); });
   it('ZIP_spanned', () => { sniffTest('application/zip', [0x50, 0x4B, 0x07, 0x08, 0x20]); });