Simple enumerate command like the datamaps one

Makefile

@@ -1,6 +1,6 @@
 PREFIX=/usr/local
 
-all: tippecanoe
+all: tippecanoe enumerate
 
 install: tippecanoe
 	cp tippecanoe $(PREFIX)/bin/tippecanoe
@@ -13,6 +13,9 @@ PG=
 tippecanoe: geojson.o jsonpull.o vector_tile.pb.o tile.o clip.o pool.o mbtiles.o
 	g++ $(PG) -O3 -g -Wall -o $@ $^ -lm -lz -lprotobuf-lite -lsqlite3
 
+enumerate: enumerate.o
+	gcc $(PG) -O3 -g -Wall -o $@ $^ -lsqlite3
+
 libjsonpull.a: jsonpull.o
 	ar rc $@ $^
 	ranlib $@

enumerate.c

@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sqlite3.h>
+
+void enumerate(char *fname) {
+	sqlite3 *db;
+
+	if (sqlite3_open(fname, &db) != SQLITE_OK) {
+		fprintf(stderr, "%s: %s\n", fname,  sqlite3_errmsg(db));
+		exit(EXIT_FAILURE);
+	}
+
+	char *sql = "SELECT zoom_level, tile_column, tile_row from tiles;";
+
+	sqlite3_stmt *stmt;
+	if (sqlite3_prepare_v2(db, sql, -1, &stmt, NULL) != SQLITE_OK) {
+		fprintf(stderr, "%s: select failed: %s\n", fname, sqlite3_errmsg(db));
+		exit(EXIT_FAILURE);
+	}
+
+	while (sqlite3_step(stmt) == SQLITE_ROW) {
+		long long zoom = sqlite3_column_int(stmt, 0);
+		long long x = sqlite3_column_int(stmt, 1);
+		long long y = sqlite3_column_int(stmt, 2);
+
+		y = (1LL << zoom) - y;
+		printf("%s %lld %lld %lld\n", fname, zoom, x, y);
+	}
+
+	sqlite3_finalize(stmt);
+
+        if (sqlite3_close(db) != SQLITE_OK) {
+                fprintf(stderr, "%s: could not close database: %s\n", fname, sqlite3_errmsg(db));
+                exit(EXIT_FAILURE);
+        }
+}
+
+void usage(char **argv) {
+	fprintf(stderr, "Usage: %s file.mbtiles ...\n", argv[0]);
+	exit(EXIT_FAILURE);
+}
+
+int main(int argc, char **argv) {
+	extern int optind;
+	extern char *optarg;
+	int i;
+
+	while ((i = getopt(argc, argv, "")) != -1) {
+		usage(argv);
+	}
+
+	if (optind >= argc) {
+		usage(argv);
+	}
+
+	for (i = optind; i < argc; i++) {
+		enumerate(argv[i]);
+	}
+
+	return 0;
+}