1 #include <u.h> 2 #include <libc.h> 3 #include <bio.h> 4 #include <ndb.h> 5 6 /* 7 * reorder the tuple to put x's line first in the entry and x fitst in its line 8 */ 9 Ndbtuple* ndbreorder(Ndbtuple * t,Ndbtuple * x)10ndbreorder(Ndbtuple *t, Ndbtuple *x) 11 { 12 Ndbtuple *nt; 13 Ndbtuple *last, *prev; 14 15 /* if x is first, we're done */ 16 if(x == t) 17 return t; 18 19 /* find end of x's line */ 20 for(last = x; last->line == last->entry; last = last->line) 21 ; 22 23 /* rotate to make this line first */ 24 if(last->line != t){ 25 26 /* detach this line and everything after it from the entry */ 27 for(nt = t; nt->entry != last->line; nt = nt->entry) 28 ; 29 nt->entry = nil; 30 31 /* switch */ 32 for(nt = last; nt->entry != nil; nt = nt->entry) 33 ; 34 nt->entry = t; 35 } 36 37 /* rotate line to make x first */ 38 if(x != last->line){ 39 40 /* find entry before x */ 41 for(prev = last; prev->line != x; prev = prev->line); 42 ; 43 44 /* detach line */ 45 nt = last->entry; 46 last->entry = last->line; 47 48 /* reattach */ 49 prev->entry = nt; 50 } 51 52 return x; 53 } 54