#include <u.h>#include <libc.h>#include <bio.h>#include "ndb.h" /* *  search for a tuple that has the given 'attr=val' and also 'rattr=x'. *  copy 'x' into 'buf' and return the whole tuple. * *  return 0 if not found. */char*ndbgetvalue(Ndb *db, Ndbs *s, char *attr, char *val, char *rattr, Ndbtuple **pp){	Ndbtuple *t, *nt;	char *rv;	Ndbs temps; 	if(s == nil)		s = &temps;	if(pp)		*pp = nil;	t = ndbsearch(db, s, attr, val);	while(t){		/* first look on same line (closer binding) */		nt = s->t;		for(;;){			if(strcmp(rattr, nt->attr) == 0){				rv = strdup(nt->val);				if(pp != nil)					*pp = t;				else					ndbfree(t);				return rv;			}			nt = nt->line;			if(nt == s->t)				break;		}		/* search whole tuple */		for(nt = t; nt; nt = nt->entry){			if(strcmp(rattr, nt->attr) == 0){				rv = strdup(nt->val);				if(pp != nil)					*pp = t;				else					ndbfree(t);				return rv;			}		}		ndbfree(t);		t = ndbsnext(s, attr, val);	}	return nil;}