lua/c开发:c-object for lua
c+lua开发中常见的实现:c库实现功能,供lua调用;
比如排行榜模块(跳表),实现方案可为:c库实现跳表(skip list)核心逻辑,提供接口供lua层中操作使用;
那么c库显然有以下的实现(伪码,演示用):
// skip list core
struct skiplist {
// ...
};
struct skiplist * skiplist_create();
void skiplist_release(struct skiplist * instance);
// ...
// interface for lua
static int
_new(lua_State *L) {
struct skiplist *psl = skiplist_create(/* param */);
struct skiplist **sl = (skiplist**) lua_newuserdata(L, sizeof(skiplist*));
*sl = psl;
lua_pushvalue(L, lua_upvalueindex(1));
lua_setmetatable(L, -2);
return 1;
}
static int
_release(lua_State *L) {
struct skiplist **psl = lua_touserdata(L, 1);
struct skiplist *sl = *psl;
skiplist_release(sl);
return 0;
}
// lib open func
int luaopen_skiplist(lua_State *L) {
luaL_Reg l[] = {
// ...
};
lua_createtable(L, 0, 2);
luaL_newlib(L, l);
lua_setfield(L, -2, "__index");
lua_pushcfunction(L, _release);
lua_setfield(L, -2, "__gc");
lua_pushcclosure(L, _new, 1);
return 1;
}
可以看到,对象在c库中创建,通过lua的full userdata保存c对象的指针,交由lua层使用,userdata设置gc元方法(调用c对象的销毁函数),在userdata被回收时正确地触发对象释放。
本文来自博客园,作者:linxx-,转载请注明原文链接:https://www.cnblogs.com/linxx-/p/18091068