mirror of https://github.com/lua/lua
118 lines
2.8 KiB
C
118 lines
2.8 KiB
C
/*
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** $Id: lref.c,v 1.8 2000/03/03 14:58:26 roberto Exp roberto $
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** reference 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 "lapi.h"
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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 lua_ref (lua_State *L, int lock) {
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int ref;
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luaA_checkCargs(L, 1);
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if (ttype(L->top-1) == TAG_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 = *(L->top-1);
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L->refArray[ref].st = lock ? LOCK : HOLD;
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}
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L->top--;
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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, "Lua API error - "
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"invalid argument 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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lua_Object lua_getref (lua_State *L, int ref) {
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if (ref == LUA_REFNIL)
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return luaA_putluaObject(L, &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 luaA_putluaObject(L, &L->refArray[ref].o);
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else
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return LUA_NOOBJECT;
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}
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void lua_beginblock (lua_State *L) {
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luaM_growvector(L, L->Cblocks, L->numCblocks, 1, struct C_Lua_Stack,
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"too many nested blocks", L->stacksize);
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L->Cblocks[L->numCblocks] = L->Cstack;
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L->numCblocks++;
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}
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void lua_endblock (lua_State *L) {
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if (L->numCblocks <= 0)
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lua_error(L, "Lua API error - no block to end");
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--L->numCblocks;
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L->Cstack = L->Cblocks[L->numCblocks];
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L->top = L->Cstack.base;
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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 TAG_STRING: case TAG_USERDATA:
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return o->value.ts->marked;
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case TAG_ARRAY:
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return o->value.a->marked;
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case TAG_LCLOSURE: case TAG_CCLOSURE:
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return o->value.cl->marked;
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case TAG_LPROTO:
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return o->value.tf->marked;
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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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