commit 6572a112c021fe35a53621b97498ef3e0538f633 from: Omar Polo date: Thu Apr 28 12:39:35 2022 UTC +rot13 example commit - 2b2bebb21a0f7fe854a1a4647057b51ff5ce279d commit + 6572a112c021fe35a53621b97498ef3e0538f633 blob - /dev/null blob + 85a97faf5bea66ea8bb8f4068c3d01bc8d9a5bad (mode 644) --- /dev/null +++ examples/rot13.bf @@ -0,0 +1,28 @@ +-,+[ Read first character and start outer character reading loop + -[ Skip forward if character is 0 + >>++++[>++++++++<-] Set up divisor (32) for division loop + (MEMORY LAYOUT: dividend copy remainder divisor quotient zero zero) + <+<-[ Set up dividend (x minus 1) and enter division loop + >+>+>-[>>>] Increase copy and remainder / reduce divisor / Normal case: skip forward + <[[>+<-]>>+>] Special case: move remainder back to divisor and increase quotient + <<<<<- Decrement dividend + ] End division loop + ]>>>[-]+ End skip loop; zero former divisor and reuse space for a flag + >--[-[<->+++[-]]]<[ Zero that flag unless quotient was 2 or 3; zero quotient; check flag + ++++++++++++<[ If flag then set up divisor (13) for second division loop + (MEMORY LAYOUT: zero copy dividend divisor remainder quotient zero zero) + >-[>+>>] Reduce divisor; Normal case: increase remainder + >[+[<+>-]>+>>] Special case: increase remainder / move it back to divisor / increase quotient + <<<<<- Decrease dividend + ] End division loop + >>[<+>-] Add remainder back to divisor to get a useful 13 + >[ Skip forward if quotient was 0 + -[ Decrement quotient and skip forward if quotient was 1 + -<<[-]>> Zero quotient and divisor if quotient was 2 + ]<<[<<->>-]>> Zero divisor and subtract 13 from copy if quotient was 1 + ]<<[<<+>>-] Zero divisor and add 13 to copy if quotient was 0 + ] End outer skip loop (jump to here if ((character minus 1)/32) was not 2 or 3) + <[-] Clear remainder from first division if second division was skipped + <.[-] Output ROT13ed character from copy and clear it + <-,+ Read next character +] End character reading loop