1866
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1 /*
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2 ** $Id: lstate.c,v 2.99 2012/10/02 17:40:53 roberto Exp $
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3 ** Global State
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4 ** See Copyright Notice in lua.h
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5 */
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6
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7
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8 #include <stddef.h>
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9 #include <string.h>
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10
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11 #define lstate_c
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12 #define LUA_CORE
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13
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14 #include "lua.h"
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15
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16 #include "lapi.h"
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17 #include "ldebug.h"
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18 #include "ldo.h"
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19 #include "lfunc.h"
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20 #include "lgc.h"
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21 #include "llex.h"
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22 #include "lmem.h"
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23 #include "lstate.h"
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24 #include "lstring.h"
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25 #include "ltable.h"
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26 #include "ltm.h"
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27
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28
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29 #if !defined(LUAI_GCPAUSE)
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30 #define LUAI_GCPAUSE 200 /* 200% */
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31 #endif
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32
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33 #if !defined(LUAI_GCMAJOR)
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34 #define LUAI_GCMAJOR 200 /* 200% */
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35 #endif
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36
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37 #if !defined(LUAI_GCMUL)
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38 #define LUAI_GCMUL 200 /* GC runs 'twice the speed' of memory allocation */
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39 #endif
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40
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41
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42 #define MEMERRMSG "not enough memory"
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43
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44
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45 /*
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46 ** a macro to help the creation of a unique random seed when a state is
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47 ** created; the seed is used to randomize hashes.
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48 */
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49 #if !defined(luai_makeseed)
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50 #include <time.h>
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51 #define luai_makeseed() cast(unsigned int, time(NULL))
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52 #endif
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53
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54
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55
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56 /*
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57 ** thread state + extra space
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58 */
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59 typedef struct LX {
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60 #if defined(LUAI_EXTRASPACE)
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61 char buff[LUAI_EXTRASPACE];
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62 #endif
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63 lua_State l;
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64 } LX;
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65
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66
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67 /*
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68 ** Main thread combines a thread state and the global state
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69 */
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70 typedef struct LG {
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71 LX l;
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72 global_State g;
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73 } LG;
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74
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75
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76
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77 #define fromstate(L) (cast(LX *, cast(lu_byte *, (L)) - offsetof(LX, l)))
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78
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79
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80 /*
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81 ** Compute an initial seed as random as possible. In ANSI, rely on
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82 ** Address Space Layout Randomization (if present) to increase
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83 ** randomness..
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84 */
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85 #define addbuff(b,p,e) \
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86 { size_t t = cast(size_t, e); \
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87 memcpy(buff + p, &t, sizeof(t)); p += sizeof(t); }
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88
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89 static unsigned int makeseed (lua_State *L) {
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90 char buff[4 * sizeof(size_t)];
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91 unsigned int h = luai_makeseed();
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92 int p = 0;
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93 addbuff(buff, p, L); /* heap variable */
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94 addbuff(buff, p, &h); /* local variable */
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95 addbuff(buff, p, luaO_nilobject); /* global variable */
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96 addbuff(buff, p, &lua_newstate); /* public function */
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97 lua_assert(p == sizeof(buff));
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98 return luaS_hash(buff, p, h);
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99 }
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100
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101
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102 /*
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103 ** set GCdebt to a new value keeping the value (totalbytes + GCdebt)
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104 ** invariant
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105 */
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106 void luaE_setdebt (global_State *g, l_mem debt) {
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107 g->totalbytes -= (debt - g->GCdebt);
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108 g->GCdebt = debt;
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109 }
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110
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111
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112 CallInfo *luaE_extendCI (lua_State *L) {
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113 CallInfo *ci = luaM_new(L, CallInfo);
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114 lua_assert(L->ci->next == NULL);
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115 L->ci->next = ci;
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116 ci->previous = L->ci;
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117 ci->next = NULL;
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118 return ci;
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119 }
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120
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121
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122 void luaE_freeCI (lua_State *L) {
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123 CallInfo *ci = L->ci;
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124 CallInfo *next = ci->next;
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125 ci->next = NULL;
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126 while ((ci = next) != NULL) {
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127 next = ci->next;
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128 luaM_free(L, ci);
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129 }
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130 }
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131
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132
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133 static void stack_init (lua_State *L1, lua_State *L) {
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134 int i; CallInfo *ci;
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135 /* initialize stack array */
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136 L1->stack = luaM_newvector(L, BASIC_STACK_SIZE, TValue);
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137 L1->stacksize = BASIC_STACK_SIZE;
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138 for (i = 0; i < BASIC_STACK_SIZE; i++)
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139 setnilvalue(L1->stack + i); /* erase new stack */
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140 L1->top = L1->stack;
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141 L1->stack_last = L1->stack + L1->stacksize - EXTRA_STACK;
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142 /* initialize first ci */
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143 ci = &L1->base_ci;
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144 ci->next = ci->previous = NULL;
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145 ci->callstatus = 0;
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146 ci->func = L1->top;
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147 setnilvalue(L1->top++); /* 'function' entry for this 'ci' */
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148 ci->top = L1->top + LUA_MINSTACK;
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149 L1->ci = ci;
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150 }
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151
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152
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153 static void freestack (lua_State *L) {
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154 if (L->stack == NULL)
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155 return; /* stack not completely built yet */
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156 L->ci = &L->base_ci; /* free the entire 'ci' list */
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157 luaE_freeCI(L);
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158 luaM_freearray(L, L->stack, L->stacksize); /* free stack array */
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159 }
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160
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161
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162 /*
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163 ** Create registry table and its predefined values
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164 */
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165 static void init_registry (lua_State *L, global_State *g) {
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166 TValue mt;
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167 /* create registry */
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168 Table *registry = luaH_new(L);
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169 sethvalue(L, &g->l_registry, registry);
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170 luaH_resize(L, registry, LUA_RIDX_LAST, 0);
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171 /* registry[LUA_RIDX_MAINTHREAD] = L */
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172 setthvalue(L, &mt, L);
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173 luaH_setint(L, registry, LUA_RIDX_MAINTHREAD, &mt);
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174 /* registry[LUA_RIDX_GLOBALS] = table of globals */
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175 sethvalue(L, &mt, luaH_new(L));
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176 luaH_setint(L, registry, LUA_RIDX_GLOBALS, &mt);
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177 }
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178
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179
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180 /*
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181 ** open parts of the state that may cause memory-allocation errors
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182 */
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183 static void f_luaopen (lua_State *L, void *ud) {
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184 global_State *g = G(L);
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185 UNUSED(ud);
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186 stack_init(L, L); /* init stack */
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187 init_registry(L, g);
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188 luaS_resize(L, MINSTRTABSIZE); /* initial size of string table */
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189 luaT_init(L);
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190 luaX_init(L);
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191 /* pre-create memory-error message */
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192 g->memerrmsg = luaS_newliteral(L, MEMERRMSG);
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193 luaS_fix(g->memerrmsg); /* it should never be collected */
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194 g->gcrunning = 1; /* allow gc */
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195 }
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196
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197
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198 /*
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199 ** preinitialize a state with consistent values without allocating
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200 ** any memory (to avoid errors)
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201 */
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202 static void preinit_state (lua_State *L, global_State *g) {
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203 G(L) = g;
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204 L->stack = NULL;
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205 L->ci = NULL;
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206 L->stacksize = 0;
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207 L->errorJmp = NULL;
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208 L->nCcalls = 0;
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209 L->hook = NULL;
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210 L->hookmask = 0;
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211 L->basehookcount = 0;
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212 L->allowhook = 1;
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213 resethookcount(L);
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214 L->openupval = NULL;
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215 L->nny = 1;
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216 L->status = LUA_OK;
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217 L->errfunc = 0;
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218 }
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219
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220
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221 static void close_state (lua_State *L) {
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222 global_State *g = G(L);
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223 luaF_close(L, L->stack); /* close all upvalues for this thread */
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224 luaC_freeallobjects(L); /* collect all objects */
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225 luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size);
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226 luaZ_freebuffer(L, &g->buff);
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227 freestack(L);
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228 lua_assert(gettotalbytes(g) == sizeof(LG));
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229 (*g->frealloc)(g->ud, fromstate(L), sizeof(LG), 0); /* free main block */
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230 }
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231
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232
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233 LUA_API lua_State *lua_newthread (lua_State *L) {
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234 lua_State *L1;
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235 lua_lock(L);
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236 luaC_checkGC(L);
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237 L1 = &luaC_newobj(L, LUA_TTHREAD, sizeof(LX), NULL, offsetof(LX, l))->th;
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238 setthvalue(L, L->top, L1);
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239 api_incr_top(L);
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240 preinit_state(L1, G(L));
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241 L1->hookmask = L->hookmask;
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242 L1->basehookcount = L->basehookcount;
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243 L1->hook = L->hook;
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244 resethookcount(L1);
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245 luai_userstatethread(L, L1);
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246 stack_init(L1, L); /* init stack */
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247 lua_unlock(L);
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248 return L1;
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249 }
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250
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251
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252 void luaE_freethread (lua_State *L, lua_State *L1) {
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253 LX *l = fromstate(L1);
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254 luaF_close(L1, L1->stack); /* close all upvalues for this thread */
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255 lua_assert(L1->openupval == NULL);
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256 luai_userstatefree(L, L1);
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257 freestack(L1);
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258 luaM_free(L, l);
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259 }
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260
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261
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262 LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
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263 int i;
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264 lua_State *L;
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265 global_State *g;
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266 LG *l = cast(LG *, (*f)(ud, NULL, LUA_TTHREAD, sizeof(LG)));
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267 if (l == NULL) return NULL;
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268 L = &l->l.l;
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269 g = &l->g;
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270 L->next = NULL;
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271 L->tt = LUA_TTHREAD;
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272 g->currentwhite = bit2mask(WHITE0BIT, FIXEDBIT);
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273 L->marked = luaC_white(g);
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274 g->gckind = KGC_NORMAL;
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275 preinit_state(L, g);
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276 g->frealloc = f;
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277 g->ud = ud;
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278 g->mainthread = L;
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279 g->seed = makeseed(L);
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280 g->uvhead.u.l.prev = &g->uvhead;
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281 g->uvhead.u.l.next = &g->uvhead;
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282 g->gcrunning = 0; /* no GC while building state */
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283 g->GCestimate = 0;
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284 g->strt.size = 0;
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285 g->strt.nuse = 0;
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286 g->strt.hash = NULL;
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287 setnilvalue(&g->l_registry);
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288 luaZ_initbuffer(L, &g->buff);
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289 g->panic = NULL;
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290 g->version = lua_version(NULL);
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291 g->gcstate = GCSpause;
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292 g->allgc = NULL;
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293 g->finobj = NULL;
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294 g->tobefnz = NULL;
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295 g->sweepgc = g->sweepfin = NULL;
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296 g->gray = g->grayagain = NULL;
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297 g->weak = g->ephemeron = g->allweak = NULL;
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298 g->totalbytes = sizeof(LG);
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299 g->GCdebt = 0;
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300 g->gcpause = LUAI_GCPAUSE;
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301 g->gcmajorinc = LUAI_GCMAJOR;
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302 g->gcstepmul = LUAI_GCMUL;
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303 for (i=0; i < LUA_NUMTAGS; i++) g->mt[i] = NULL;
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304 if (luaD_rawrunprotected(L, f_luaopen, NULL) != LUA_OK) {
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305 /* memory allocation error: free partial state */
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306 close_state(L);
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307 L = NULL;
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308 }
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309 else
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310 luai_userstateopen(L);
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311 return L;
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312 }
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313
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314
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315 LUA_API void lua_close (lua_State *L) {
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316 L = G(L)->mainthread; /* only the main thread can be closed */
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317 lua_lock(L);
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318 luai_userstateclose(L);
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319 close_state(L);
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320 }
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321
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322
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