Developed by zxing,zbar

Zxing and Zbar are both open-source to scan barcodes or 2-D "graphical barcodes" and retrieve the data encoded.

Zxing

ZXing refer to short for Zebra Crossing. It is implement in the Barcode Scanner (application) that is an Android app.You can visit the website of Barcode Scanner or download the project from Google

Zbar

ZBar is an open-source C barcode reading library with C++, Python, Perl, and Ruby bindings. It is also implemented on Linux and Microsoft Windows as a command-line application, and as an iPhone application