blob: a9b3b515b4b15d7167bc812d4ee5bee88e1db668 [file] [log] [blame]
/*
** $Id: ltm.c,v 1.24 1999/02/26 15:48:55 roberto Exp roberto $
** Tag methods
** See Copyright Notice in lua.h
*/
#include <stdio.h>
#include <string.h>
#include "lauxlib.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "ltm.h"
char *luaT_eventname[] = { /* ORDER IM */
"gettable", "settable", "index", "getglobal", "setglobal", "add",
"sub", "mul", "div", "pow", "unm", "lt", "le", "gt", "ge",
"concat", "gc", "function", NULL
};
static int luaI_checkevent (char *name, char *list[]) {
int e = luaL_findstring(name, list);
if (e < 0)
luaL_verror("`%.50s' is not a valid event name", name);
return e;
}
/* events in LUA_T_NIL are all allowed, since this is used as a
* 'placeholder' for "default" fallbacks
*/
static char luaT_validevents[NUM_TAGS][IM_N] = { /* ORDER LUA_T, ORDER IM */
{1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1}, /* LUA_T_USERDATA */
{1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1}, /* LUA_T_NUMBER */
{1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, /* LUA_T_STRING */
{0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, /* LUA_T_ARRAY */
{1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0}, /* LUA_T_PROTO */
{1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0}, /* LUA_T_CPROTO */
{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1} /* LUA_T_NIL */
};
static int luaT_validevent (int t, int e) { /* ORDER LUA_T */
return (t < LUA_T_NIL) ? 1 : luaT_validevents[-t][e];
}
static void init_entry (int tag) {
int i;
for (i=0; i<IM_N; i++)
ttype(luaT_getim(tag, i)) = LUA_T_NIL;
}
void luaT_init (void) {
int t;
L->last_tag = -(NUM_TAGS-1);
luaM_growvector(L->IMtable, 0, NUM_TAGS, struct IM, arrEM, MAX_INT);
for (t=L->last_tag; t<=0; t++)
init_entry(t);
}
int lua_newtag (void) {
--L->last_tag;
luaM_growvector(L->IMtable, -(L->last_tag), 1, struct IM, arrEM, MAX_INT);
init_entry(L->last_tag);
return L->last_tag;
}
static void checktag (int tag) {
if (!(L->last_tag <= tag && tag <= 0))
luaL_verror("%d is not a valid tag", tag);
}
void luaT_realtag (int tag) {
if (!(L->last_tag <= tag && tag < LUA_T_NIL))
luaL_verror("tag %d was not created by `newtag'", tag);
}
int lua_copytagmethods (int tagto, int tagfrom) {
int e;
checktag(tagto);
checktag(tagfrom);
for (e=0; e<IM_N; e++) {
if (luaT_validevent(tagto, e))
*luaT_getim(tagto, e) = *luaT_getim(tagfrom, e);
}
return tagto;
}
int luaT_effectivetag (TObject *o) {
int t;
switch (t = ttype(o)) {
case LUA_T_ARRAY:
return o->value.a->htag;
case LUA_T_USERDATA: {
int tag = o->value.ts->u.d.tag;
return (tag >= 0) ? LUA_T_USERDATA : tag;
}
case LUA_T_CLOSURE:
return o->value.cl->consts[0].ttype;
#ifdef DEBUG
case LUA_T_PMARK: case LUA_T_CMARK:
case LUA_T_CLMARK: case LUA_T_LINE:
LUA_INTERNALERROR("invalid type");
#endif
default:
return t;
}
}
TObject *luaT_gettagmethod (int t, char *event) {
int e = luaI_checkevent(event, luaT_eventname);
checktag(t);
if (luaT_validevent(t, e))
return luaT_getim(t,e);
else
return &luaO_nilobject;
}
void luaT_settagmethod (int t, char *event, TObject *func) {
TObject temp;
int e = luaI_checkevent(event, luaT_eventname);
checktag(t);
if (!luaT_validevent(t, e))
luaL_verror("cannot change tag method `%.20s' for type `%.20s'%.20s",
luaT_eventname[e], luaO_typenames[-t],
(t == LUA_T_ARRAY || t == LUA_T_USERDATA) ? " with default tag"
: "");
temp = *func;
*func = *luaT_getim(t,e);
*luaT_getim(t, e) = temp;
}
char *luaT_travtagmethods (int (*fn)(TObject *)) { /* ORDER IM */
int e;
for (e=IM_GETTABLE; e<=IM_FUNCTION; e++) {
int t;
for (t=0; t>=L->last_tag; t--)
if (fn(luaT_getim(t,e)))
return luaT_eventname[e];
}
return NULL;
}
/*
* ===================================================================
* compatibility with old fallback system
*/
#ifdef LUA_COMPAT2_5
#include "lapi.h"
#include "lstring.h"
static void errorFB (void)
{
lua_Object o = lua_getparam(1);
if (lua_isstring(o))
fprintf(stderr, "lua: %s\n", lua_getstring(o));
else
fprintf(stderr, "lua: unknown error\n");
}
static void nilFB (void) { }
static void typeFB (void) {
lua_error("unexpected type");
}
static void fillvalids (IMS e, TObject *func) {
int t;
for (t=LUA_T_NIL; t<=LUA_T_USERDATA; t++)
if (luaT_validevent(t, e))
*luaT_getim(t, e) = *func;
}
void luaT_setfallback (void) {
static char *oldnames [] = {"error", "getglobal", "arith", "order", NULL};
TObject oldfunc;
lua_CFunction replace;
char *name = luaL_check_string(1);
lua_Object func = lua_getparam(2);
luaL_arg_check(lua_isfunction(func), 2, "function expected");
switch (luaL_findstring(name, oldnames)) {
case 0: { /* old error fallback */
TObject *em = &(luaS_new("_ERRORMESSAGE")->u.s.globalval);
oldfunc = *em;
*em = *luaA_Address(func);
replace = errorFB;
break;
}
case 1: /* old getglobal fallback */
oldfunc = *luaT_getim(LUA_T_NIL, IM_GETGLOBAL);
*luaT_getim(LUA_T_NIL, IM_GETGLOBAL) = *luaA_Address(func);
replace = nilFB;
break;
case 2: { /* old arith fallback */
int i;
oldfunc = *luaT_getim(LUA_T_NUMBER, IM_POW);
for (i=IM_ADD; i<=IM_UNM; i++) /* ORDER IM */
fillvalids(i, luaA_Address(func));
replace = typeFB;
break;
}
case 3: { /* old order fallback */
int i;
oldfunc = *luaT_getim(LUA_T_NIL, IM_LT);
for (i=IM_LT; i<=IM_GE; i++) /* ORDER IM */
fillvalids(i, luaA_Address(func));
replace = typeFB;
break;
}
default: {
int e;
if ((e = luaL_findstring(name, luaT_eventname)) >= 0) {
oldfunc = *luaT_getim(LUA_T_NIL, e);
fillvalids(e, luaA_Address(func));
replace = (e == IM_GC || e == IM_INDEX) ? nilFB : typeFB;
}
else {
luaL_verror("`%.50s' is not a valid fallback name", name);
replace = NULL; /* to avoid warnings */
}
}
}
if (oldfunc.ttype != LUA_T_NIL)
luaA_pushobject(&oldfunc);
else
lua_pushcfunction(replace);
}
#endif