mirror of
https://github.com/lua/lua
synced 2024-12-24 19:36:50 +03:00
172 lines
4.6 KiB
C
172 lines
4.6 KiB
C
/*
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** $Id: ltm.c,v 1.32 2000/02/22 18:12:46 roberto Exp roberto $
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** Tag methods
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** See Copyright Notice in lua.h
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*/
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#include <stdio.h>
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#include <string.h>
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#define LUA_REENTRANT
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#include "lauxlib.h"
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#include "lmem.h"
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#include "lobject.h"
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#include "lstate.h"
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#include "ltm.h"
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const char *const luaT_eventname[] = { /* ORDER IM */
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"gettable", "settable", "index", "getglobal", "setglobal", "add", "sub",
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"mul", "div", "pow", "unm", "lt", "concat", "gc", "function", NULL
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};
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static int luaI_checkevent (lua_State *L, const char *name, const char *const list[]) {
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int e = luaL_findstring(name, list);
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if (e < 0)
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luaL_verror(L, "`%.50s' is not a valid event name", name);
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return e;
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}
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/* events in LUA_T_NIL are all allowed, since this is used as a
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* 'placeholder' for "default" fallbacks
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*/
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/* ORDER LUA_T, ORDER IM */
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static const char luaT_validevents[NUM_TAGS][IM_N] = {
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{1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1}, /* LUA_T_USERDATA */
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{1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1}, /* LUA_T_NUMBER */
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{1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, /* LUA_T_STRING */
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{0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1}, /* LUA_T_ARRAY */
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{1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0}, /* LUA_T_LPROTO */
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{1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0}, /* LUA_T_CPROTO */
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{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1} /* LUA_T_NIL */
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};
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int luaT_validevent (int t, int e) { /* ORDER LUA_T */
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#ifdef LUA_COMPAT_GC
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if (t == LUA_T_ARRAY && e == IM_GC)
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return 1; /* old versions allowed gc tag method for tables */
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#endif
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return (t < LUA_T_NIL) ? 1 : luaT_validevents[-t][e];
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}
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static void init_entry (lua_State *L, int tag) {
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int i;
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for (i=0; i<IM_N; i++)
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ttype(luaT_getim(L, tag, i)) = LUA_T_NIL;
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}
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void luaT_init (lua_State *L) {
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int t;
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L->last_tag = -(NUM_TAGS-1);
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luaM_growvector(L, L->IMtable, 0, NUM_TAGS, struct IM, arrEM, MAX_INT);
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for (t=L->last_tag; t<=0; t++)
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init_entry(L, t);
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}
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int lua_newtag (lua_State *L) {
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--L->last_tag;
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luaM_growvector(L, L->IMtable, -(L->last_tag), 1, struct IM, arrEM, MAX_INT);
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init_entry(L, L->last_tag);
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return L->last_tag;
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}
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static void checktag (lua_State *L, int tag) {
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if (!(L->last_tag <= tag && tag <= 0))
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luaL_verror(L, "%d is not a valid tag", tag);
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}
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void luaT_realtag (lua_State *L, int tag) {
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if (!(L->last_tag <= tag && tag < LUA_T_NIL))
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luaL_verror(L, "tag %d was not created by `newtag'", tag);
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}
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int lua_copytagmethods (lua_State *L, int tagto, int tagfrom) {
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int e;
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checktag(L, tagto);
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checktag(L, tagfrom);
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for (e=0; e<IM_N; e++) {
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if (luaT_validevent(tagto, e))
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*luaT_getim(L, tagto, e) = *luaT_getim(L, tagfrom, e);
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}
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return tagto;
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}
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int luaT_effectivetag (const TObject *o) {
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static const int realtag[] = { /* ORDER LUA_T */
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LUA_T_USERDATA, LUA_T_NUMBER, LUA_T_STRING, LUA_T_ARRAY,
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LUA_T_LPROTO, LUA_T_CPROTO, LUA_T_NIL,
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LUA_T_LPROTO, LUA_T_CPROTO, /* LUA_T_LCLOSURE, LUA_T_CCLOSURE */
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};
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int t;
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switch (t = ttype(o)) {
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case LUA_T_USERDATA: {
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int tag = o->value.ts->u.d.tag;
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return (tag >= 0) ? LUA_T_USERDATA : tag; /* deprecated test */
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}
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case LUA_T_ARRAY: return o->value.a->htag;
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default: return realtag[-t];
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}
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}
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const TObject *luaT_gettagmethod (lua_State *L, int t, const char *event) {
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int e;
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#ifdef LUA_COMPAT_ORDER_TM
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static const char *old_order[] = {"le", "gt", "ge", NULL};
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if (luaL_findstring(event, old_order) >= 0)
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return &luaO_nilobject;
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#endif
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e = luaI_checkevent(L, event, luaT_eventname);
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checktag(L, t);
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if (luaT_validevent(t, e))
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return luaT_getim(L, t,e);
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else
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return &luaO_nilobject;
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}
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void luaT_settagmethod (lua_State *L, int t, const char *event, TObject *func) {
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TObject temp;
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int e;
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#ifdef LUA_COMPAT_ORDER_TM
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static const char *old_order[] = {"le", "gt", "ge", NULL};
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if (luaL_findstring(event, old_order) >= 0)
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return; /* do nothing for old operators */
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#endif
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e = luaI_checkevent(L, event, luaT_eventname);
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checktag(L, t);
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if (!luaT_validevent(t, e))
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luaL_verror(L, "cannot change `%.20s' tag method for type `%.20s'%.20s",
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luaT_eventname[e], luaO_typenames[-t],
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(t == LUA_T_ARRAY || t == LUA_T_USERDATA) ? " with default tag"
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: "");
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temp = *func;
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*func = *luaT_getim(L, t,e);
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*luaT_getim(L, t, e) = temp;
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}
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const char *luaT_travtagmethods (lua_State *L,
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int (*fn)(lua_State *, TObject *)) { /* ORDER IM */
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int e;
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for (e=IM_GETTABLE; e<=IM_FUNCTION; e++) {
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int t;
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for (t=0; t>=L->last_tag; t--)
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if (fn(L, luaT_getim(L, t,e)))
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return luaT_eventname[e];
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}
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return NULL;
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}
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