int8_t vs size_t

[Arkadiy Vertleyb (BLOOMBERG/ 120 PARK)]

Hi all.

Throughout the entire project, int64_t rather than size_t is consistently used 
to denote size and offset.

This causes massive amount of compiler warnings in the 32 bit system.

Is it an oversight or a conscious design decision?  If latter, what is the 
reason behind it?

Thanks,
Arkadiy