Shared Dictionary Compression for Efficient Mobile Software Distribution

Jinheng Li, Qiao Li, Qingan Li, Chun Jason Xue

Abstract: The distribution of software to small devices, such as smartphones, requires significant resources in terms of network bandwidth, server storage, and energy consumption during the upload and download process. In addition, software distribution platforms like Apple's App Store and Google's Play Store impose restrictions on maximum software size, emphasizing the importance of code size reduction. While traditional compression tools can help minimize redundancies within files, this paper demonstrates the presence of considerable redundancies across different files that are not addressed by existing methods. To remedy this, we propose a novel approach to reduce code size by compressing instructions at the intermediate representation (IR) layer, which is supported as a distribution format by Apple. Our method identifies and extracts common sub-strings among instructions across all IR files, creating a shared dictionary. When combined with conventional compression tools for packaging, this technique achieves an average mobile software size reduction of 24.49% compared to using zip compression alone, thereby alleviating software distribution costs for small devices.