explode

Documentation

Overview

Package explode is for use with the archive/zip package.

Explode was a decompression method authored in 1989 by Phil Katz and used in his MS-DOS compression tool, PKZip v0.91.

It is referred to as ZIP Implode/Explode method 6 and is based on the LZ77 algorithm.

This package was first prompted using Gemini in August 2026 and manually cleaned to be idiomatic and readable.

In 2020, Jason Summers authored a collection of public domain libraries named oldunzip. In-depth information on Implode was authored by Hans Wennborg in 2021, who programmed the public domain implode.c.

Example

Example demonstrates the basic usage of the package.

package main

import (
	"archive/zip"
	"fmt"
	"hash/crc32"
	"io"
	"path/filepath"

	"github.com/Defacto2/archive/explode"
)

func main() {
	const testdata = "testdata"
	const testFile = "example-i.zip"

	// Register the Explode decompressor with the archive zip package.
	explode.Register()

	name := filepath.Join(testdata, testFile)
	rc, _ := zip.OpenReader(name)
	defer rc.Close()

	for n, f := range rc.File {
		fr, _ := f.Open()
		hasher := crc32.NewIEEE()
		size := int64(f.UncompressedSize64) //nolint:gosec
		_, _ = io.CopyN(hasher, fr, size)

		fmt.Printf("%d. Decompressed method %d: %s, %dB\n"+
			"Stored zip crc32 %x, and copied to buffer: %x\n",
			n+1, f.Method, f.Name, f.UncompressedSize64, f.CRC32, hasher.Sum32())

		fr.Close()
	}
}

Output:
1. Decompressed method 6: I.BIN, 2048B
Stored zip crc32 8314ddd9, and copied to buffer: 8314ddd9

Index

• Constants
• Variables
• func Register()

Examples

• Package

Constants

const Explode uint16 = 6 // Method 6: Implode/Explode

Variables

var (
	ErrCorruptHeader = errors.New("explode: corrupt Shannon-Fano tree header")
	ErrCorruptStream = errors.New("explode: corrupt compressed stream")
)

Functions

func Register

func Register()

Register the Explode method globally for archive/zip.