  The ubiquity of variable-length integers in data storage and communication
necessitates efficient decoding techniques. In this paper, we present SFVInt, a
simple and fast approach to decode the prevalent Little Endian Base-128
(LEB128) varints. Our approach effectively utilizes the Bit Manipulation
Instruction Set 2 (BMI2) in modern Intel and AMD processors, achieving
significant performance improvement while maintaining simplicity and avoiding
overengineering. SFVInt, with its generic design, effectively processes both
32-bit and 64-bit unsigned integers using a unified code template, marking a
significant leap forward in varint decoding efficiency. We thoroughly evaluate
SFVInt's performance across various datasets and scenarios, demonstrating that
it achieves up to a 2x increase in decoding speed when compared to varint
decoding methods used in established frameworks like Facebook Folly and Google
Protobuf.
