Introduction

Zar is a software for collecting many files into one archive img. It is optimized for golang and read-only mmap random read. Since this is used for read-only image file system, it doesn't contain various file system parameters such as time stamps, ownership and permissions.

Structure

zar img file looks like this:

| file 1 data |...| file n data | files metadata lists | files metadata start offset

files metadata is a list consisting of the following structs:

type fileMetadata struct {
	Begin int64
	End int64
	Name string
}

Begin indicated the file start offset. End indicated the file end offset. Name indicated the file name. (Note: In the next version we will support folders. If there is a file bar.txt in folder foo, the Name field will be "foo/bar.txt")

Enviornment Setup

1. Add the zar directory to the GOPATH by running (if added at home dir):

export GOPATH=$HOME/zar

2. Add the bin directory to golang enviorment by running (if added at home dir):

export GOBIN=$HOME/zar/bin

Build

Run go build src/zar.main.go.

Usage

To create a zar image for a folder, you can run ./bin/main -w -dir=<folder path>. e.g. ./bin/main -w -dir=./test. If you need to set the output image name and location, add -o <image path>. By default it uses test.img.

To read a zar image for a folder, you can run ./bin/main -r. If you need to set the input image name and location, add -img <image path>. By default it uses test.img.