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/*
** $Id: ltm.c,v 1.70 2001/03/02 17:27:50 roberto Exp roberto $
** Tag methods
** See Copyright Notice in lua.h
*/
#include <stdio.h>
#include <string.h>
#define LUA_PRIVATE
#include "lua.h"
#include "ldo.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "lstring.h"
#include "ltable.h"
#include "ltm.h"
const l_char *const luaT_eventname[] = { /* ORDER TM */
l_s("gettable"), l_s("settable"), l_s("index"), l_s("getglobal"), l_s("setglobal"), l_s("add"), l_s("sub"),
l_s("mul"), l_s("div"), l_s("pow"), l_s("unm"), l_s("lt"), l_s("concat"), l_s("gc"), l_s("function"),
l_s("le"), l_s("gt"), l_s("ge"), /* deprecated options!! */
NULL
};
static int findevent (const l_char *name) {
int i;
for (i=0; luaT_eventname[i]; i++)
if (strcmp(luaT_eventname[i], name) == 0)
return i;
return -1; /* name not found */
}
static int luaI_checkevent (lua_State *L, const l_char *name, int t) {
int e = findevent(name);
if (e >= TM_N)
luaO_verror(L, l_s("event `%.50s' is deprecated"), name);
if (e == TM_GC && t == LUA_TTABLE)
luaO_verror(L, l_s("event `gc' for tables is deprecated"));
if (e < 0)
luaO_verror(L, l_s("`%.50s' is not a valid event name"), name);
return e;
}
/* events in LUA_TNIL are all allowed, since this is used as a
* `placeholder' for default fallbacks
*/
/* ORDER LUA_T, ORDER TM */
static const lu_byte luaT_validevents[NUM_TAGS][TM_N] = {
{1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1}, /* LUA_TUSERDATA */
{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, /* LUA_TNIL */
{1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1}, /* LUA_TNUMBER */
{1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, /* LUA_TSTRING */
{0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1}, /* LUA_TTABLE */
{1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0} /* LUA_TFUNCTION */
};
int luaT_validevent (int t, int e) { /* ORDER LUA_T */
return (t >= NUM_TAGS) ? 1 : (int)luaT_validevents[t][e];
}
void luaT_init (lua_State *L) {
static const l_char *const typenames[NUM_TAGS] = {
l_s("userdata"), l_s("nil"), l_s("number"), l_s("string"), l_s("table"), l_s("function")
};
int i;
for (i=0; i<NUM_TAGS; i++)
luaT_newtag(L, typenames[i], i);
}
int luaT_newtag (lua_State *L, const l_char *name, int basictype) {
int tag;
int i;
TString *ts;
luaM_growvector(L, G(L)->TMtable, G(L)->ntag, G(L)->sizeTM, struct TM,
MAX_INT, l_s("tag table overflow"));
tag = G(L)->ntag;
if (name == NULL)
ts = NULL;
else {
TObject *v;
ts = luaS_new(L, name);
v = luaH_setstr(L, G(L)->type2tag, ts);
if (ttype(v) != LUA_TNIL) return LUA_TNONE; /* invalid name */
setnvalue(v, tag);
}
for (i=0; i<TM_N; i++)
luaT_gettm(G(L), tag, i) = NULL;
G(L)->TMtable[tag].collected = NULL;
G(L)->TMtable[tag].name = ts;
G(L)->TMtable[tag].basictype = basictype;
G(L)->ntag++;
return tag;
}
static void checktag (lua_State *L, int tag) {
if (!(0 <= tag && tag < G(L)->ntag))
luaO_verror(L, l_s("%d is not a valid tag"), tag);
}
LUA_API int lua_copytagmethods (lua_State *L, int tagto, int tagfrom) {
int e;
lua_lock(L);
checktag(L, tagto);
checktag(L, tagfrom);
for (e=0; e<TM_N; e++) {
if (luaT_validevent(tagto, e))
luaT_gettm(G(L), tagto, e) = luaT_gettm(G(L), tagfrom, e);
}
lua_unlock(L);
return tagto;
}
int luaT_tag (const TObject *o) {
int t = ttype(o);
switch (t) {
case LUA_TUSERDATA: return tsvalue(o)->u.d.tag;
case LUA_TTABLE: return hvalue(o)->htag;
default: return t;
}
}
const l_char *luaT_typename (global_State *G, const TObject *o) {
int t = ttype(o);
int tag;
TString *ts;
switch (t) {
case LUA_TUSERDATA:
tag = tsvalue(o)->u.d.tag;
break;
case LUA_TTABLE:
tag = hvalue(o)->htag;
break;
default:
tag = t;
}
ts = G->TMtable[tag].name;
if (ts == NULL)
ts = G->TMtable[t].name;
return getstr(ts);
}
LUA_API void lua_gettagmethod (lua_State *L, int t, const l_char *event) {
int e;
lua_lock(L);
e = luaI_checkevent(L, event, t);
checktag(L, t);
if (luaT_validevent(t, e) && luaT_gettm(G(L), t, e)) {
setclvalue(L->top, luaT_gettm(G(L), t, e));
}
else
setnilvalue(L->top);
incr_top;
lua_unlock(L);
}
LUA_API void lua_settagmethod (lua_State *L, int t, const l_char *event) {
int e;
lua_lock(L);
e = luaI_checkevent(L, event, t);
checktag(L, t);
if (!luaT_validevent(t, e))
luaO_verror(L, l_s("cannot change `%.20s' tag method for type `%.20s'%.20s"),
luaT_eventname[e], basictypename(G(L), t),
(t == LUA_TTABLE || t == LUA_TUSERDATA) ?
l_s(" with default tag") : l_s(""));
switch (ttype(L->top - 1)) {
case LUA_TNIL:
luaT_gettm(G(L), t, e) = NULL;
break;
case LUA_TFUNCTION:
luaT_gettm(G(L), t, e) = clvalue(L->top - 1);
break;
default:
luaD_error(L, l_s("tag method must be a function (or nil)"));
}
L->top--;
lua_unlock(L);
}
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