| #include <u.h> |
| #include <libc.h> |
| #include <bio.h> |
| #include <ndb.h> |
| |
| /* |
| * reorder the tuple to put x's line first in the entry and x fitst in its line |
| */ |
| Ndbtuple* |
| ndbreorder(Ndbtuple *t, Ndbtuple *x) |
| { |
| Ndbtuple *nt; |
| Ndbtuple *last, *prev; |
| |
| /* if x is first, we're done */ |
| if(x == t) |
| return t; |
| |
| /* find end of x's line */ |
| for(last = x; last->line == last->entry; last = last->line) |
| ; |
| |
| /* rotate to make this line first */ |
| if(last->line != t){ |
| |
| /* detach this line and everything after it from the entry */ |
| for(nt = t; nt->entry != last->line; nt = nt->entry) |
| ; |
| nt->entry = nil; |
| |
| /* switch */ |
| for(nt = last; nt->entry != nil; nt = nt->entry) |
| ; |
| nt->entry = t; |
| } |
| |
| /* rotate line to make x first */ |
| if(x != last->line){ |
| |
| /* find entry before x */ |
| for(prev = last; prev->line != x; prev = prev->line); |
| ; |
| |
| /* detach line */ |
| nt = last->entry; |
| last->entry = last->line; |
| |
| /* reattach */ |
| prev->entry = nt; |
| } |
| |
| return x; |
| } |