libs: introduce lmo - Lua Machine Objects, an implementation of binary hash tables

1 files changed, 124 insertions, 0 deletions

diff --git a/libs/lmo/src/lmo_lualib.c b/libs/lmo/src/lmo_lualib.c
new file mode 100644
index 0000000000..3f9170e887
--- /dev/null
+++ b/libs/lmo/src/lmo_lualib.c
@@ -0,0 +1,124 @@
+/*
+ * lmo - Lua Machine Objects - Lookup utility
+ *
+ *   Copyright (C) 2009 Jo-Philipp Wich <xm@subsignal.org>
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+#include "lmo_lualib.h"
+
+extern char _lmo_error[1024];
+
+
+static int lmo_L_open(lua_State *L) {
+	const char *filename = luaL_checklstring(L, 1, NULL);
+	lmo_archive_t *ar, **udata;
+
+	if( (ar = lmo_open(filename)) != NULL )
+	{
+		if( (udata = lua_newuserdata(L, sizeof(lmo_archive_t *))) != NULL )
+		{
+			*udata = ar;
+			luaL_getmetatable(L, LMO_ARCHIVE_META);
+			lua_setmetatable(L, -2);
+			return 1;
+		}
+
+		lua_pushnil(L);
+		lua_pushstring(L, "out of memory");
+		return 2;
+	}
+
+	lua_pushnil(L);
+	lua_pushstring(L, lmo_error());
+	return 2;
+}
+
+static int lmo_L_hash(lua_State *L) {
+	const char *data = luaL_checkstring(L, 1);
+	uint32_t hash = sfh_hash(data, strlen(data));
+	lua_pushnumber(L, hash);
+	return 1;
+}
+
+static int lmo_L_lookup(lua_State *L) {
+	lmo_archive_t **ar = luaL_checkudata(L, 1, LMO_ARCHIVE_META);
+	lmo_entry_t *e = (*ar)->index;
+	const char *key = luaL_checkstring(L, 2);
+	uint32_t hash = sfh_hash(key, strlen(key));
+
+	while( e != NULL )
+	{
+		if( e->key_id == hash )
+		{
+			lua_pushlstring(L, &(*ar)->mmap[e->offset], e->length);
+			return 1;
+		}
+
+		e = e->next;
+	}
+
+	lua_pushnil(L);
+	return 1;
+}
+
+static int lmo_L__gc(lua_State *L) {
+	lmo_archive_t **ar = luaL_checkudata(L, 1, LMO_ARCHIVE_META);
+
+	if( (*ar) != NULL )
+		lmo_close(*ar);
+
+	*ar = NULL;
+
+	return 0;
+}
+
+static int lmo_L__tostring(lua_State *L) {
+	lmo_archive_t **ar = luaL_checkudata(L, 1, LMO_ARCHIVE_META);
+	lua_pushfstring(L, "LMO Archive (%d bytes)", (*ar)->length);
+	return 1;
+}
+
+
+/* method table */
+static const luaL_reg M[] = {
+	{"close",	lmo_L__gc},
+	{"lookup",	lmo_L_lookup},
+	{"__tostring",	lmo_L__tostring},
+	{"__gc",	lmo_L__gc},
+	{NULL,		NULL}
+};
+
+/* module table */
+static const luaL_reg R[] = {
+	{"open",	lmo_L_open},
+	{"hash",	lmo_L_hash},
+	{NULL,		NULL}
+};
+
+LUALIB_API int luaopen_lmo(lua_State *L) {
+	luaL_newmetatable(L, LMO_LUALIB_META);
+	luaL_register(L, NULL, R);
+	lua_pushvalue(L, -1);
+	lua_setfield(L, -2, "__index");
+	lua_setglobal(L, LMO_LUALIB_META);
+
+	luaL_newmetatable(L, LMO_ARCHIVE_META);
+	luaL_register(L, NULL, M);
+	lua_pushvalue(L, -1);
+	lua_setfield(L, -2, "__index");
+	lua_setglobal(L, LMO_ARCHIVE_META);
+
+	return 1;
+}