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/*
** $Id: ltm.c,v 1.46 2000/08/09 19:16:57 roberto Exp roberto $
** Tag methods
** See Copyright Notice in lua.h
*/
#include <stdio.h>
#include <string.h>
#include "lua.h"
#include "lauxlib.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "ltm.h"
const char *const luaT_eventname[] = { /* ORDER IM */
"gettable", "settable", "index", "getglobal", "setglobal", "add", "sub",
"mul", "div", "pow", "unm", "lt", "concat", "gc", "function",
"le", "gt", "ge", /* deprecated options!! */
NULL
};
static int luaI_checkevent (lua_State *L, const char *name, int t) {
int e = luaL_findstring(name, luaT_eventname);
if (e >= IM_N)
luaL_verror(L, "event `%.50s' is deprecated", name);
if (e == IM_GC && t == TAG_TABLE)
luaL_verror(L, "event `gc' for tables is deprecated");
if (e < 0)
luaL_verror(L, "`%.50s' is not a valid event name", name);
return e;
}
/* events in TAG_NIL are all allowed, since this is used as a
* 'placeholder' for "default" fallbacks
*/
/* ORDER LUA_T, ORDER IM */
static const char luaT_validevents[NUM_TAGS][IM_N] = {
{1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1}, /* TAG_USERDATA */
{1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1}, /* TAG_NUMBER */
{1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, /* TAG_STRING */
{0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1}, /* TAG_TABLE */
{1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0}, /* TAG_LCLOSURE */
{1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0}, /* TAG_CCLOSURE */
{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1} /* TAG_NIL */
};
int luaT_validevent (int t, int e) { /* ORDER LUA_T */
return (t > TAG_NIL) ? 1 : luaT_validevents[t][e];
}
static void init_entry (lua_State *L, int tag) {
int i;
for (i=0; i<IM_N; i++)
ttype(luaT_getim(L, tag, i)) = TAG_NIL;
L->IMtable[tag].collected = NULL;
}
void luaT_init (lua_State *L) {
int t;
luaM_growvector(L, L->IMtable, 0, NUM_TAGS, struct IM, "", MAX_INT);
L->last_tag = NUM_TAGS-1;
for (t=0; t<=L->last_tag; t++)
init_entry(L, t);
}
int lua_newtag (lua_State *L) {
luaM_growvector(L, L->IMtable, L->last_tag, 1, struct IM,
"tag table overflow", MAX_INT);
L->last_tag++;
init_entry(L, L->last_tag);
return L->last_tag;
}
static void checktag (lua_State *L, int tag) {
if (!(0 <= tag && tag <= L->last_tag))
luaL_verror(L, "%d is not a valid tag", tag);
}
void luaT_realtag (lua_State *L, int tag) {
if (!(NUM_TAGS <= tag && tag <= L->last_tag))
luaL_verror(L, "tag %d was not created by `newtag'", tag);
}
int lua_copytagmethods (lua_State *L, int tagto, int tagfrom) {
int e;
checktag(L, tagto);
checktag(L, tagfrom);
for (e=0; e<IM_N; e++) {
if (luaT_validevent(tagto, e))
*luaT_getim(L, tagto, e) = *luaT_getim(L, tagfrom, e);
}
return tagto;
}
int luaT_effectivetag (lua_State *L, const TObject *o) {
lua_Type t = ttype(o);
switch (t) {
case TAG_USERDATA: {
int tag = tsvalue(o)->u.d.tag;
return (tag > L->last_tag) ? TAG_USERDATA : tag; /* deprecated test */
}
case TAG_TABLE: return hvalue(o)->htag;
default: return t;
}
}
void lua_gettagmethod (lua_State *L, int t, const char *event) {
int e;
e = luaI_checkevent(L, event, t);
checktag(L, t);
if (luaT_validevent(t, e))
*L->top = *luaT_getim(L, t,e);
else
ttype(L->top) = TAG_NIL;
L->top++;
}
void lua_settagmethod (lua_State *L, int t, const char *event) {
TObject temp;
int e;
LUA_ASSERT(lua_isnil(L, -1) || lua_isfunction(L, -1),
"function or nil expected");
e = luaI_checkevent(L, event, t);
checktag(L, t);
if (!luaT_validevent(t, e))
luaL_verror(L, "cannot change `%.20s' tag method for type `%.20s'%.20s",
luaT_eventname[e], luaO_typenames[t],
(t == TAG_TABLE || t == TAG_USERDATA) ? " with default tag"
: "");
temp = *(L->top - 1);
*(L->top - 1) = *luaT_getim(L, t,e);
*luaT_getim(L, t, e) = temp;
}
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