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#include "lua_type.h"

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#include <lua5.1/lauxlib.h>

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void lua_type_register (lua_State *L, const struct lua_type *type, const struct lua_method methods[])

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{

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    const struct lua_method *method;

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    // create the metatable

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    luaL_newmetatable(L, type->name);

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    // set the metatable __index to itself

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    lua_pushvalue(L, -1);

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    lua_setfield(L, -1, "__index");

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    // add the methods to the metatable

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    for (method = methods; method->func; method++) {

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        lua_pushcfunction(L, method->func);

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        lua_setfield(L, -2, method->name);

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    }

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}

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void* lua_type_create (lua_State *L, const struct lua_type *type, size_t size)

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{

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    // create the new userdata on the stack

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    void *ud = lua_newuserdata(L, size);

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    // get the type and set it

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    luaL_getmetatable(L, type->name);

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    lua_setmetatable(L, -2);

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    // ok

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    return ud;

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}

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void* lua_type_register_global (lua_State *L, const struct lua_type *type, const struct lua_method methods[],

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        const char *global_name, size_t size)

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{

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    // allocate the global object

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    void *obj = lua_newuserdata(L, size);

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    // create the type metatable

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    lua_type_register(L, type, methods);

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    // set the userdata's metatable

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    lua_setmetatable(L, -2);

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    // store it as a global

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    lua_setglobal(L, global_name);

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    // ok

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    return obj;

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}

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void* lua_type_get (lua_State *L, const struct lua_type *type, int index)

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{

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    void *ud;

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    // validate the userdata arg

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    // XXX: the luaL_checkudata actually raises an error itself

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    if ((ud = luaL_checkudata(L, index, type->name)) == NULL) {

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        luaL_error(L, "bad type argument: `%s` expected", type->name); return NULL;

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    } else {

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        // ok

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        return ud;

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    }

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}