mirror of
https://github.com/lua/lua
synced 2024-12-26 20:29:43 +03:00
98 lines
2.4 KiB
C
98 lines
2.4 KiB
C
/*
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** $Id: lref.c,v 1.2 1999/11/10 15:37:50 roberto Exp roberto $
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** REF mechanism
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** See Copyright Notice in lua.h
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*/
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#define LUA_REENTRANT
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#include "lmem.h"
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#include "lref.h"
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#include "lstate.h"
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#include "lua.h"
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int luaR_ref (lua_State *L, const TObject *o, int lock) {
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int ref;
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if (ttype(o) == LUA_T_NIL)
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ref = LUA_REFNIL;
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else {
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if (L->refFree != NONEXT) { /* is there a free place? */
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ref = L->refFree;
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L->refFree = L->refArray[ref].st;
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}
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else { /* no more free places */
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luaM_growvector(L, L->refArray, L->refSize, 1, struct ref, refEM, MAX_INT);
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ref = L->refSize++;
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}
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L->refArray[ref].o = *o;
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L->refArray[ref].st = lock ? LOCK : HOLD;
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}
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return ref;
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}
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void lua_unref (lua_State *L, int ref) {
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if (ref >= 0) {
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if (ref >= L->refSize || L->refArray[ref].st >= 0)
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lua_error(L, "API error - invalid parameter for function `lua_unref'");
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L->refArray[ref].st = L->refFree;
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L->refFree = ref;
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}
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}
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const TObject *luaR_getref (lua_State *L, int ref) {
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if (ref == LUA_REFNIL)
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return &luaO_nilobject;
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else if (0 <= ref && ref < L->refSize &&
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(L->refArray[ref].st == LOCK || L->refArray[ref].st == HOLD))
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return &L->refArray[ref].o;
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else
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return NULL;
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}
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static int ismarked (const TObject *o) {
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/* valid only for locked objects */
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switch (o->ttype) {
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case LUA_T_STRING: case LUA_T_USERDATA:
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return o->value.ts->marked;
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case LUA_T_ARRAY:
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return o->value.a->marked;
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case LUA_T_CLOSURE:
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return o->value.cl->marked;
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case LUA_T_PROTO:
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return o->value.tf->marked;
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#ifdef DEBUG
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case LUA_T_LINE: case LUA_T_CLMARK:
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case LUA_T_CMARK: case LUA_T_PMARK:
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LUA_INTERNALERROR(L, "invalid type");
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#endif
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default: /* number or cproto */
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return 1;
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}
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}
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/* for internal debugging only; check if a link of free refs is valid */
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#define VALIDLINK(L, st,n) (NONEXT <= (st) && (st) < (n))
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void luaR_invalidaterefs (lua_State *L) {
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int n = L->refSize;
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int i;
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for (i=0; i<n; i++) {
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struct ref *r = &L->refArray[i];
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if (r->st == HOLD && !ismarked(&r->o))
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r->st = COLLECTED;
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LUA_ASSERT(L, (r->st == LOCK && ismarked(&r->o)) ||
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r->st == COLLECTED ||
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r->st == NONEXT ||
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(r->st < n && VALIDLINK(L, L->refArray[r->st].st, n)),
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"inconsistent ref table");
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}
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LUA_ASSERT(L, VALIDLINK(L, L->refFree, n), "inconsistent ref table");
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}
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