error: Wire.h: No such file or directory

Using Arduino Programming Questions
13

I dont think so because everything worked as sketch, now that I'm turning it into a library it raises errors, but funcs and their use is just copy-pasted from the sketch

I tried to replay both parameter and return type (byte-short, both individually and together) but it just changes the error to a type conversion issue so I think this is not the solution T_T

EDIT: for completeness the whole errors report is

RTCReader\RTCReader.cpp.o: In function RTCReader::getDateTime(short*, short*, short*, short*, short*, short*, short*)': C:\Users\Daedalus\Documents\Arduino\libraries\RTCReader/RTCReader.cpp:72: undefined reference to RTCReader::bcdToDec(short)'
C:\Users\Daedalus\Documents\Arduino\libraries\RTCReader/RTCReader.cpp:73: undefined reference to RTCReader::bcdToDec(short)' C:\Users\Daedalus\Documents\Arduino\libraries\RTCReader/RTCReader.cpp:74: undefined reference to RTCReader::bcdToDec(short)'
C:\Users\Daedalus\Documents\Arduino\libraries\RTCReader/RTCReader.cpp:75: undefined reference to RTCReader::bcdToDec(short)' C:\Users\Daedalus\Documents\Arduino\libraries\RTCReader/RTCReader.cpp:76: undefined reference to RTCReader::bcdToDec(short)'
RTCReader\RTCReader.cpp.o:C:\Users\Daedalus\Documents\Arduino\libraries\RTCReader/RTCReader.cpp:77: more undefined references to `RTCReader::bcdToDec(short)' follow