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