--- a/libnumdb/Makefile	Sun Jun 26 13:24:47 2022 -0800
+++ b/libnumdb/Makefile	Sun Jun 26 13:39:52 2022 -0800
@@ -1,6 +1,6 @@
 CC=	gcc
 CFLAGS=	-O2
-OBJS=	readbin.o refresh.o
+OBJS=	check_nanp.o readbin.o refresh.o
 LIB=	libnumdb.a
 
 all:	${LIB}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libnumdb/check_nanp.c	Sun Jun 26 13:39:52 2022 -0800
@@ -0,0 +1,40 @@
+/*
+ * The library function implemented in this module consults ThemWi number db
+ * to see if a given NANP number is owned by us or not.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include "../include/number_db_file.h"
+
+extern struct numdb_file_hdr numdb_hdr;
+extern uint64_t *numdb_owned_numbers;
+
+static int
+compare_owned_num(p1, p2)
+	uint64_t *p1, *p2;
+{
+	if (*p1 < *p2)
+		return(-1);
+	else if (*p1 > *p2)
+		return(1);
+	else
+		return(0);
+}
+
+is_nanp_locally_owned(numstr)
+	char *numstr;
+{
+	uint64_t key, *res;
+
+	if (!numdb_owned_numbers || !numdb_hdr.owned_number_count)
+		return(0);
+	key = strtoull(numstr, 0, 10);
+	res = bsearch(&key, numdb_owned_numbers, numdb_hdr.owned_number_count,
+			sizeof(uint64_t), compare_owned_num);
+	if (res)
+		return(1);
+	else
+		return(0);
+}