database - Use of compressed GTFS data in Android app -


i looking develop transit app using gtfs static data. 1 of constraints i've set myself app should use minimal mobile data transfers. therefore, embed data in app.

my issue gtfs data sets quite large (85mb uncompressed city of sydney example). i've done bit of reverse engineering on other apps out there , found out of them have managed compress data smaller file (i'm talking few mb @ most).

using 7zip, i've managed compress 85mb data set down 5mb acceptable me. next step me use 7z file app , that's i'm stuck. there's no way i'm going uncompress , put in sql database use space on phone. wondering other options.

thanks

first, embedding, recommend using embedded xz library (similar 7zip). have embedded in project , had luck it. sure compress data using 'xz --check=crc32' it's compatible embedded xz, , remember initialize crc table.

as decompression strategy, may need segment data in such way can decompress different parts of on demand (i.e., tree of databases). i'm not familiar data's characteristics. user need loaded @ same time? or can compartmentalized?

also, xz can bit slow, decode. have evaluated how regular gzip performs? tends a) fast; , b) available standard part of embedded , mobile frameworks.


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