@linxuekai/bsdiff-cli

Binary diff/patch CLI powered by bsdiff-wasm (WebAssembly).

Generates compact binary deltas between two files and applies them to reconstruct the new file — ideal for incremental updates, OTA patches, and version-to-version binary diffs.

Requirements

• Node.js >= 18

Install

npm install -g @linxuekai/bsdiff-cli

CLI Usage

bsdiff diff  <old-file> <new-file> <patch-out>   # Create a binary patch
bsdiff patch <old-file> <patch-file> <new-out>   # Apply a binary patch

Options

| Flag | Description | |------|-------------| | -h, --help | Show help | | -v, --version | Show version |

Examples

# Generate a patch from v1.bin → v2.bin
bsdiff diff v1.bin v2.bin update.patch

# Apply the patch to restore v2.bin
bsdiff patch v1.bin update.patch v2-restored.bin

Output

diff:

diff: v1.bin → v2.bin ⇒ update.patch
  old    1.2 MB
  new    1.3 MB
  patch  45.2 KB
  ratio  3.4% of new

patch:

patch: v1.bin + update.patch ⇒ v2-restored.bin
  old      1.2 MB
  patch    45.2 KB
  restored 1.3 MB

Programmatic API

import { diff, patch } from '@linxuekai/bsdiff-cli';

diff(oldFile, newFile, patchOut)

Generate a binary patch file.

| Parameter | Type | Description | |-----------|------|-------------| | oldFile | string | Path to the original file | | newFile | string | Path to the new file | | patchOut | string | Path where the patch will be written |

Returns: Promise<{ oldSize: number, newSize: number, patchSize: number }>

patch(oldFile, patchFile, outFile)

Apply a binary patch to reconstruct the new file.

| Parameter | Type | Description | |-----------|------|-------------| | oldFile | string | Path to the original file | | patchFile | string | Path to the patch file | | outFile | string | Path where the restored file will be written |

Returns: Promise<{ oldSize: number, patchSize: number, outSize: number }>

API Example

import { diff, patch } from '@linxuekai/bsdiff-cli';

// Create a patch
const result = await diff('v1.bin', 'v2.bin', 'update.patch');
console.log(`Patch size: ${result.patchSize} bytes`);

// Apply the patch
const restored = await patch('v1.bin', 'update.patch', 'v2-restored.bin');
console.log(`Restored size: ${restored.outSize} bytes`);

How It Works

The library wraps the classic bsdiff/bspatch algorithms compiled to WebAssembly via bsdiff-wasm. File paths are resolved to a common ancestor directory, which is mounted into the WASM module's NODEFS virtual filesystem. The underlying C main() is then invoked with relative paths.

License

MIT