add lmdb.next and pairs(db)

1 files changed, 43 insertions, 0 deletions

diff --git a/lmdb.c b/lmdb.c
index 7e562c0..d85ce4f 100644
--- a/lmdb.c
+++ b/lmdb.c
@@ -276,6 +276,47 @@ static int db_put(lua_State *L) {
 	return 0;
 }
 
+static int db_next(lua_State *L) {
+	lua_settop(L, 2);
+	MDB_dbi dbi = *(MDB_dbi *) luaL_checkudata(L, 1, "lmdb.db");
+	check_env(L, 1);
+	luaL_argcheck(
+		L, lua_isnil(L, 2) || lua_isstring(L, 2), 2, "expected string or nil");
+
+	lua_getuservalue(L, 1);
+	struct handle *tud = lua_touserdata(L, -1);
+	MDB_cursor *curs;
+	asserr(mdb_cursor_open(tud->obj, dbi, &curs));
+
+	MDB_val key;
+	MDB_val data;
+	int result;
+	if (!lua_isnil(L, 2)) {
+		key = toval(L, 2);
+		asserr(mdb_cursor_get(curs, &key, &data, MDB_SET));
+		result = mdb_cursor_get(curs, &key, &data, MDB_NEXT);
+	} else
+		result = mdb_cursor_get(curs, &key, &data, MDB_FIRST);
+	if (result == MDB_NOTFOUND) {
+		lua_pushnil(L);
+		return 1;
+	} else asserr(result);
+
+	fromval(L, key);
+	fromval(L, data);
+	mdb_cursor_close(curs);
+	return 2;
+}
+
+static int db_pairs(lua_State *L) {
+	lua_settop(L, 1);
+	luaL_checkudata(L, 1, "lmdb.db");
+	lua_pushcfunction(L, db_next);
+	lua_pushvalue(L, 1);
+	lua_pushnil(L);
+	return 3;
+}
+
 static int db_drop(lua_State *L) {
 	lua_settop(L, 2);
 	struct handle *ud = luaL_checkudata(L, 1, "lmdb.txn");
@@ -294,6 +335,7 @@ static int db_drop(lua_State *L) {
 static const struct luaL_Reg lmdb[] = {
 	{"open", env_open},
 	{"version", version},
+	{"next", db_next},
 	{NULL, NULL},
 };
 
@@ -322,6 +364,7 @@ static const struct luaL_Reg lmdb_txn[] = {
 static const struct luaL_Reg lmdb_db[] = {
 	{"__index", db_get},
 	{"__newindex", db_put},
+	{"__pairs", db_pairs},
 	{NULL, NULL},
 };