mirror of
https://github.com/libretro/scummvm.git
synced 2024-12-14 21:59:17 +00:00
332 lines
9.2 KiB
C++
332 lines
9.2 KiB
C++
/*
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** $Id$
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** Dynamic library loader for Lua
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** See Copyright Notice in lua.h
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**
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** This module contains an implementation of loadlib for Unix systems
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** that have dlfcn, an implementation for Darwin (Mac OS X), an
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** implementation for Windows, and a stub for other systems.
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*/
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#define loadlib_c
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#define LUA_LIB
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#include "lua.h"
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#include "lauxlib.h"
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#include "lualib.h"
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/* prefix for open functions in C libraries */
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#define LUA_POF "luaopen_"
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/* separator for open functions in C libraries */
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#define LUA_OFSEP "_"
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#define LIBPREFIX "LOADLIB: "
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#define POF LUA_POF
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#define LIB_FAIL "open"
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/*
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** {======================================================
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** Fallback for other systems
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** =======================================================
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*/
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#undef LIB_FAIL
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#define LIB_FAIL "absent"
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#define DLMSG "dynamic libraries not enabled; check your Lua installation"
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/* }====================================================== */
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static void **ll_register (lua_State *L, const char *path) {
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void **plib;
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lua_pushfstring(L, "%s%s", LIBPREFIX, path);
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lua_gettable(L, LUA_REGISTRYINDEX); /* check library in registry? */
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if (!lua_isnil(L, -1)) /* is there an entry? */
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plib = (void **)lua_touserdata(L, -1);
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else { /* no entry yet; create one */
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lua_pop(L, 1);
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plib = (void **)lua_newuserdata(L, sizeof(const void *));
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*plib = NULL;
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luaL_getmetatable(L, "_LOADLIB");
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lua_setmetatable(L, -2);
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lua_pushfstring(L, "%s%s", LIBPREFIX, path);
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lua_pushvalue(L, -2);
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lua_settable(L, LUA_REGISTRYINDEX);
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}
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return plib;
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}
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/*
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** __gc tag method: calls library's `ll_unloadlib' function with the lib
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** handle
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*/
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static int gctm (lua_State *L) {
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void **lib = (void **)luaL_checkudata(L, 1, "_LOADLIB");
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*lib = NULL; /* mark library as closed */
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return 0;
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}
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/* error codes for ll_loadfunc */
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#define ERRLIB 1
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#define ERRFUNC 2
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static int ll_loadlib (lua_State *L) {
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const char *path = luaL_checkstring(L, 1);
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// const char *init = luaL_checkstring(L, 2);
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int stat;
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void **reg = ll_register(L, path);
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if (*reg == NULL) {
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stat = ERRLIB; /* unable to load library */
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} else {
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stat = ERRFUNC; /* unable to find function */
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}
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lua_pushliteral(L, DLMSG);
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/* error; error message is on stack top */
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lua_pushnil(L);
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lua_insert(L, -2);
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lua_pushstring(L, (stat == ERRLIB) ? LIB_FAIL : "init");
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return 3; /* return nil, error message, and where */
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}
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/*
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** {======================================================
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** 'require' function
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** =======================================================
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*/
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static int loader_preload (lua_State *L) {
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const char *name = luaL_checkstring(L, 1);
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lua_getfield(L, LUA_ENVIRONINDEX, "preload");
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if (!lua_istable(L, -1))
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luaL_error(L, LUA_QL("package.preload") " must be a table");
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lua_getfield(L, -1, name);
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if (lua_isnil(L, -1)) /* not found? */
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lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
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return 1;
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}
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static /*const*/ int sentinel_ = 0;
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#define sentinel ((void *)&sentinel_)
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static int ll_require (lua_State *L) {
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const char *name = luaL_checkstring(L, 1);
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int i;
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lua_settop(L, 1); /* _LOADED table will be at index 2 */
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lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
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lua_getfield(L, 2, name);
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if (lua_toboolean(L, -1)) { /* is it there? */
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if (lua_touserdata(L, -1) == sentinel) /* check loops */
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luaL_error(L, "loop or previous error loading module " LUA_QS, name);
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return 1; /* package is already loaded */
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}
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/* else must load it; iterate over available loaders */
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lua_getfield(L, LUA_ENVIRONINDEX, "loaders");
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if (!lua_istable(L, -1))
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luaL_error(L, LUA_QL("package.loaders") " must be a table");
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lua_pushliteral(L, ""); /* error message accumulator */
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for (i=1; ; i++) {
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lua_rawgeti(L, -2, i); /* get a loader */
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if (lua_isnil(L, -1))
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luaL_error(L, "module " LUA_QS " not found:%s",
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name, lua_tostring(L, -2));
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lua_pushstring(L, name);
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lua_call(L, 1, 1); /* call it */
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if (lua_isfunction(L, -1)) /* did it find module? */
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break; /* module loaded successfully */
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else if (lua_isstring(L, -1)) /* loader returned error message? */
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lua_concat(L, 2); /* accumulate it */
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else
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lua_pop(L, 1);
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}
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lua_pushlightuserdata(L, sentinel);
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lua_setfield(L, 2, name); /* _LOADED[name] = sentinel */
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lua_pushstring(L, name); /* pass name as argument to module */
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lua_call(L, 1, 1); /* run loaded module */
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if (!lua_isnil(L, -1)) /* non-nil return? */
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lua_setfield(L, 2, name); /* _LOADED[name] = returned value */
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lua_getfield(L, 2, name);
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if (lua_touserdata(L, -1) == sentinel) { /* module did not set a value? */
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lua_pushboolean(L, 1); /* use true as result */
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lua_pushvalue(L, -1); /* extra copy to be returned */
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lua_setfield(L, 2, name); /* _LOADED[name] = true */
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}
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return 1;
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}
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/* }====================================================== */
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/*
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** {======================================================
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** 'module' function
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** =======================================================
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*/
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static void setfenv (lua_State *L) {
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lua_Debug ar;
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lua_getstack(L, 1, &ar);
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lua_getinfo(L, "f", &ar);
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lua_pushvalue(L, -2);
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lua_setfenv(L, -2);
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lua_pop(L, 1);
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}
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static void dooptions (lua_State *L, int n) {
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int i;
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for (i = 2; i <= n; i++) {
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lua_pushvalue(L, i); /* get option (a function) */
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lua_pushvalue(L, -2); /* module */
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lua_call(L, 1, 0);
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}
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}
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static void modinit (lua_State *L, const char *modname) {
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const char *dot;
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lua_pushvalue(L, -1);
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lua_setfield(L, -2, "_M"); /* module._M = module */
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lua_pushstring(L, modname);
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lua_setfield(L, -2, "_NAME");
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dot = strrchr(modname, '.'); /* look for last dot in module name */
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if (dot == NULL) dot = modname;
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else dot++;
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/* set _PACKAGE as package name (full module name minus last part) */
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lua_pushlstring(L, modname, dot - modname);
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lua_setfield(L, -2, "_PACKAGE");
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}
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static int ll_module (lua_State *L) {
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const char *modname = luaL_checkstring(L, 1);
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int loaded = lua_gettop(L) + 1; /* index of _LOADED table */
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lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
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lua_getfield(L, loaded, modname); /* get _LOADED[modname] */
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if (!lua_istable(L, -1)) { /* not found? */
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lua_pop(L, 1); /* remove previous result */
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/* try global variable (and create one if it does not exist) */
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if (luaL_findtable(L, LUA_GLOBALSINDEX, modname, 1) != NULL)
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return luaL_error(L, "name conflict for module " LUA_QS, modname);
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lua_pushvalue(L, -1);
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lua_setfield(L, loaded, modname); /* _LOADED[modname] = new table */
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}
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/* check whether table already has a _NAME field */
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lua_getfield(L, -1, "_NAME");
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if (!lua_isnil(L, -1)) /* is table an initialized module? */
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lua_pop(L, 1);
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else { /* no; initialize it */
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lua_pop(L, 1);
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modinit(L, modname);
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}
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lua_pushvalue(L, -1);
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setfenv(L);
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dooptions(L, loaded - 1);
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return 0;
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}
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static int ll_seeall (lua_State *L) {
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luaL_checktype(L, 1, LUA_TTABLE);
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if (!lua_getmetatable(L, 1)) {
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lua_createtable(L, 0, 1); /* create new metatable */
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lua_pushvalue(L, -1);
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lua_setmetatable(L, 1);
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}
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lua_pushvalue(L, LUA_GLOBALSINDEX);
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lua_setfield(L, -2, "__index"); /* mt.__index = _G */
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return 0;
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}
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/* }====================================================== */
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static void setpath (lua_State *L, const char *fieldname, const char *envname,
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const char *def) {
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// no environment variable -> use default
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lua_pushstring(L, def);
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lua_setfield(L, -2, fieldname);
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}
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static const luaL_Reg pk_funcs[] = {
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{"loadlib", ll_loadlib},
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{"seeall", ll_seeall},
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{NULL, NULL}
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};
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static const luaL_Reg ll_funcs[] = {
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{"module", ll_module},
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{"require", ll_require},
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{NULL, NULL}
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};
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static const lua_CFunction loaders[] =
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{loader_preload, NULL};
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LUALIB_API int luaopen_package (lua_State *L) {
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int i;
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/* create new type _LOADLIB */
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luaL_newmetatable(L, "_LOADLIB");
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lua_pushcfunction(L, gctm);
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lua_setfield(L, -2, "__gc");
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/* create `package' table */
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luaL_register(L, LUA_LOADLIBNAME, pk_funcs);
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#if defined(LUA_COMPAT_LOADLIB)
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lua_getfield(L, -1, "loadlib");
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lua_setfield(L, LUA_GLOBALSINDEX, "loadlib");
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#endif
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lua_pushvalue(L, -1);
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lua_replace(L, LUA_ENVIRONINDEX);
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/* create `loaders' table */
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lua_createtable(L, 0, sizeof(loaders)/sizeof(loaders[0]) - 1);
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/* fill it with pre-defined loaders */
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for (i=0; loaders[i] != NULL; i++) {
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lua_pushcfunction(L, loaders[i]);
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lua_rawseti(L, -2, i+1);
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}
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lua_setfield(L, -2, "loaders"); /* put it in field `loaders' */
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setpath(L, "path", LUA_PATH, LUA_PATH_DEFAULT); /* set field `path' */
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setpath(L, "cpath", LUA_CPATH, LUA_CPATH_DEFAULT); /* set field `cpath' */
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/* store config information */
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lua_pushliteral(L, LUA_DIRSEP "\n" LUA_PATHSEP "\n" LUA_PATH_MARK "\n"
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LUA_EXECDIR "\n" LUA_IGMARK);
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lua_setfield(L, -2, "config");
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/* set field `loaded' */
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luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 2);
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lua_setfield(L, -2, "loaded");
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/* set field `preload' */
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lua_newtable(L);
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lua_setfield(L, -2, "preload");
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lua_pushvalue(L, LUA_GLOBALSINDEX);
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luaL_register(L, NULL, ll_funcs); /* open lib into global table */
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lua_pop(L, 1);
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return 1; /* return 'package' table */
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}
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