new

src/libndb/ndbgetval.c

@@ -0,0 +1,75 @@
+#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;
+}
+
+Ndbtuple*
+ndbgetval(Ndb *db, Ndbs *s, char *attr, char *val, char *rattr, char *buf)
+{
+	Ndbtuple *t;
+	char *p;
+
+	p = ndbgetvalue(db, s, attr, val, rattr, &t);
+	if(p == nil){
+		if(buf != nil)
+			*buf = 0;
+	} else {
+		if(buf != nil){
+			strncpy(buf, p, Ndbvlen-1);
+			buf[Ndbvlen-1] = 0;
+		}
+		free(p);
+	}
+	return t;
+}