source: trunk/src/lua/lcorolib.c @ 2540

Last change on this file since 2540 was 2540, checked in by sam, 10 years ago

core: import pristine lua 5.2.1 in the engine code.

File size: 3.5 KB
Line 
1/*
2** $Id: lcorolib.c,v 1.4 2012/04/27 18:59:04 roberto Exp $
3** Coroutine Library
4** See Copyright Notice in lua.h
5*/
6
7
8#include <stdlib.h>
9
10
11#define lcorolib_c
12#define LUA_LIB
13
14#include "lua.h"
15
16#include "lauxlib.h"
17#include "lualib.h"
18
19
20static int auxresume (lua_State *L, lua_State *co, int narg) {
21  int status;
22  if (!lua_checkstack(co, narg)) {
23    lua_pushliteral(L, "too many arguments to resume");
24    return -1;  /* error flag */
25  }
26  if (lua_status(co) == LUA_OK && lua_gettop(co) == 0) {
27    lua_pushliteral(L, "cannot resume dead coroutine");
28    return -1;  /* error flag */
29  }
30  lua_xmove(L, co, narg);
31  status = lua_resume(co, L, narg);
32  if (status == LUA_OK || status == LUA_YIELD) {
33    int nres = lua_gettop(co);
34    if (!lua_checkstack(L, nres + 1)) {
35      lua_pop(co, nres);  /* remove results anyway */
36      lua_pushliteral(L, "too many results to resume");
37      return -1;  /* error flag */
38    }
39    lua_xmove(co, L, nres);  /* move yielded values */
40    return nres;
41  }
42  else {
43    lua_xmove(co, L, 1);  /* move error message */
44    return -1;  /* error flag */
45  }
46}
47
48
49static int luaB_coresume (lua_State *L) {
50  lua_State *co = lua_tothread(L, 1);
51  int r;
52  luaL_argcheck(L, co, 1, "coroutine expected");
53  r = auxresume(L, co, lua_gettop(L) - 1);
54  if (r < 0) {
55    lua_pushboolean(L, 0);
56    lua_insert(L, -2);
57    return 2;  /* return false + error message */
58  }
59  else {
60    lua_pushboolean(L, 1);
61    lua_insert(L, -(r + 1));
62    return r + 1;  /* return true + `resume' returns */
63  }
64}
65
66
67static int luaB_auxwrap (lua_State *L) {
68  lua_State *co = lua_tothread(L, lua_upvalueindex(1));
69  int r = auxresume(L, co, lua_gettop(L));
70  if (r < 0) {
71    if (lua_isstring(L, -1)) {  /* error object is a string? */
72      luaL_where(L, 1);  /* add extra info */
73      lua_insert(L, -2);
74      lua_concat(L, 2);
75    }
76    lua_error(L);  /* propagate error */
77  }
78  return r;
79}
80
81
82static int luaB_cocreate (lua_State *L) {
83  lua_State *NL;
84  luaL_checktype(L, 1, LUA_TFUNCTION);
85  NL = lua_newthread(L);
86  lua_pushvalue(L, 1);  /* move function to top */
87  lua_xmove(L, NL, 1);  /* move function from L to NL */
88  return 1;
89}
90
91
92static int luaB_cowrap (lua_State *L) {
93  luaB_cocreate(L);
94  lua_pushcclosure(L, luaB_auxwrap, 1);
95  return 1;
96}
97
98
99static int luaB_yield (lua_State *L) {
100  return lua_yield(L, lua_gettop(L));
101}
102
103
104static int luaB_costatus (lua_State *L) {
105  lua_State *co = lua_tothread(L, 1);
106  luaL_argcheck(L, co, 1, "coroutine expected");
107  if (L == co) lua_pushliteral(L, "running");
108  else {
109    switch (lua_status(co)) {
110      case LUA_YIELD:
111        lua_pushliteral(L, "suspended");
112        break;
113      case LUA_OK: {
114        lua_Debug ar;
115        if (lua_getstack(co, 0, &ar) > 0)  /* does it have frames? */
116          lua_pushliteral(L, "normal");  /* it is running */
117        else if (lua_gettop(co) == 0)
118            lua_pushliteral(L, "dead");
119        else
120          lua_pushliteral(L, "suspended");  /* initial state */
121        break;
122      }
123      default:  /* some error occurred */
124        lua_pushliteral(L, "dead");
125        break;
126    }
127  }
128  return 1;
129}
130
131
132static int luaB_corunning (lua_State *L) {
133  int ismain = lua_pushthread(L);
134  lua_pushboolean(L, ismain);
135  return 2;
136}
137
138
139static const luaL_Reg co_funcs[] = {
140  {"create", luaB_cocreate},
141  {"resume", luaB_coresume},
142  {"running", luaB_corunning},
143  {"status", luaB_costatus},
144  {"wrap", luaB_cowrap},
145  {"yield", luaB_yield},
146  {NULL, NULL}
147};
148
149
150
151LUAMOD_API int luaopen_coroutine (lua_State *L) {
152  luaL_newlib(L, co_funcs);
153  return 1;
154}
155
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