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/*
** $Id: lcorolib.c,v 1.5 2013/02/21 13:44:53 roberto Exp $
** Coroutine Library
** See Copyright Notice in lua.h
*/
#include <stdlib.h>
#define lcorolib_c
#define LUA_LIB
#include "lua.h"
#include "lauxlib.h"
#include "lualib.h"
static int auxresume (lua_State *L, lua_State *co, int narg) {
int status;
if (!lua_checkstack(co, narg)) {
lua_pushliteral(L, "too many arguments to resume");
return -1; /* error flag */
}
if (lua_status(co) == LUA_OK && lua_gettop(co) == 0) {
lua_pushliteral(L, "cannot resume dead coroutine");
return -1; /* error flag */
}
lua_xmove(L, co, narg);
status = lua_resume(co, L, narg);
if (status == LUA_OK || status == LUA_YIELD) {
int nres = lua_gettop(co);
if (!lua_checkstack(L, nres + 1)) {
lua_pop(co, nres); /* remove results anyway */
lua_pushliteral(L, "too many results to resume");
return -1; /* error flag */
}
lua_xmove(co, L, nres); /* move yielded values */
return nres;
}
else {
lua_xmove(co, L, 1); /* move error message */
return -1; /* error flag */
}
}
static int luaB_coresume (lua_State *L) {
lua_State *co = lua_tothread(L, 1);
int r;
luaL_argcheck(L, co, 1, "coroutine expected");
r = auxresume(L, co, lua_gettop(L) - 1);
if (r < 0) {
lua_pushboolean(L, 0);
lua_insert(L, -2);
return 2; /* return false + error message */
}
else {
lua_pushboolean(L, 1);
lua_insert(L, -(r + 1));
return r + 1; /* return true + `resume' returns */
}
}
static int luaB_auxwrap (lua_State *L) {
lua_State *co = lua_tothread(L, lua_upvalueindex(1));
int r = auxresume(L, co, lua_gettop(L));
if (r < 0) {
if (lua_isstring(L, -1)) { /* error object is a string? */
luaL_where(L, 1); /* add extra info */
lua_insert(L, -2);
lua_concat(L, 2);
}
return lua_error(L); /* propagate error */
}
return r;
}
static int luaB_cocreate (lua_State *L) {
lua_State *NL;
luaL_checktype(L, 1, LUA_TFUNCTION);
NL = lua_newthread(L);
lua_pushvalue(L, 1); /* move function to top */
lua_xmove(L, NL, 1); /* move function from L to NL */
return 1;
}
static int luaB_cowrap (lua_State *L) {
luaB_cocreate(L);
lua_pushcclosure(L, luaB_auxwrap, 1);
return 1;
}
static int luaB_yield (lua_State *L) {
return lua_yield(L, lua_gettop(L));
}
static int luaB_costatus (lua_State *L) {
lua_State *co = lua_tothread(L, 1);
luaL_argcheck(L, co, 1, "coroutine expected");
if (L == co) lua_pushliteral(L, "running");
else {
switch (lua_status(co)) {
case LUA_YIELD:
lua_pushliteral(L, "suspended");
break;
case LUA_OK: {
lua_Debug ar;
if (lua_getstack(co, 0, &ar) > 0) /* does it have frames? */
lua_pushliteral(L, "normal"); /* it is running */
else if (lua_gettop(co) == 0)
lua_pushliteral(L, "dead");
else
lua_pushliteral(L, "suspended"); /* initial state */
break;
}
default: /* some error occurred */
lua_pushliteral(L, "dead");
break;
}
}
return 1;
}
static int luaB_corunning (lua_State *L) {
int ismain = lua_pushthread(L);
lua_pushboolean(L, ismain);
return 2;
}
static const luaL_Reg co_funcs[] = {
{"create", luaB_cocreate},
{"resume", luaB_coresume},
{"running", luaB_corunning},
{"status", luaB_costatus},
{"wrap", luaB_cowrap},
{"yield", luaB_yield},
{NULL, NULL}
};
LUAMOD_API int luaopen_coroutine (lua_State *L) {
luaL_newlib(L, co_funcs);
return 1;
}
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