ref: 1787584ad839002584e0752e4df41b6f3b70064b
dir: /sys/src/libndb/ndbreorder.c/
#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; }