blob: 12c4509d097d60e62e288f900a57d1653ac54956 [file] [log] [blame]
/*
** fallback.c
** TecCGraf - PUC-Rio
*/
char *rcs_fallback="$Id: fallback.c,v 2.3 1997/04/06 14:08:08 roberto Exp roberto $";
#include <stdio.h>
#include <string.h>
#include "auxlib.h"
#include "luamem.h"
#include "fallback.h"
#include "opcode.h"
#include "lua.h"
#include "table.h"
#include "tree.h"
#include "hash.h"
/* -------------------------------------------
** Reference routines
*/
static struct ref {
TObject o;
enum {LOCK, HOLD, FREE, COLLECTED} status;
} *refArray = NULL;
static int refSize = 0;
int luaI_ref (TObject *object, int lock)
{
int i;
int oldSize;
if (ttype(object) == LUA_T_NIL)
return -1; /* special ref for nil */
for (i=0; i<refSize; i++)
if (refArray[i].status == FREE)
goto found;
/* no more empty spaces */
oldSize = refSize;
refSize = growvector(&refArray, refSize, struct ref, refEM, MAX_WORD);
for (i=oldSize; i<refSize; i++)
refArray[i].status = FREE;
i = oldSize;
found:
refArray[i].o = *object;
refArray[i].status = lock ? LOCK : HOLD;
return i;
}
void lua_unref (int ref)
{
if (ref >= 0 && ref < refSize)
refArray[ref].status = FREE;
}
TObject *luaI_getref (int ref)
{
static TObject nul = {LUA_T_NIL, {0}};
if (ref == -1)
return &nul;
if (ref >= 0 && ref < refSize &&
(refArray[ref].status == LOCK || refArray[ref].status == HOLD))
return &refArray[ref].o;
else
return NULL;
}
void luaI_travlock (int (*fn)(TObject *))
{
int i;
for (i=0; i<refSize; i++)
if (refArray[i].status == LOCK)
fn(&refArray[i].o);
}
void luaI_invalidaterefs (void)
{
int i;
for (i=0; i<refSize; i++)
if (refArray[i].status == HOLD && !luaI_ismarked(&refArray[i].o))
refArray[i].status = COLLECTED;
}
/* -------------------------------------------
* Internal Methods
*/
char *luaI_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 = luaI_findstring(name, list);
if (e < 0)
luaL_verror("`%s' is not a valid event name", name);
return e;
}
static struct IM {
TObject int_method[IM_N];
} *luaI_IMtable = NULL;
static int IMtable_size = 0;
static int last_tag = LUA_T_NIL; /* ORDER LUA_T */
static char validevents[NUM_TYPES][IM_N] = { /* ORDER LUA_T, ORDER IM */
{1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, /* LUA_T_USERDATA */
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, /* LUA_T_LINE */
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, /* LUA_T_CMARK */
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, /* LUA_T_MARK */
{1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0}, /* LUA_T_CFUNCTION */
{1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0}, /* LUA_T_FUNCTION */
{0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, /* LUA_T_ARRAY */
{1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, /* LUA_T_STRING */
{1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1}, /* LUA_T_NUMBER */
{0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0} /* LUA_T_NIL */
};
static int validevent (lua_Type t, int e)
{ /* ORDER LUA_T */
return (t < LUA_T_NIL) ? 1 : validevents[-t][e];
}
static void init_entry (int tag)
{
int i;
for (i=0; i<IM_N; i++)
luaI_IMtable[-tag].int_method[i].ttype = LUA_T_NIL;
}
void luaI_initfallbacks (void)
{
if (luaI_IMtable == NULL) {
int i;
IMtable_size = NUM_TYPES+10;
luaI_IMtable = newvector(IMtable_size, struct IM);
for (i=LUA_T_NIL; i<=LUA_T_USERDATA; i++)
init_entry(i);
}
}
int lua_newtag (void)
{
--last_tag;
if ((-last_tag) >= IMtable_size) {
luaI_initfallbacks();
IMtable_size = growvector(&luaI_IMtable, IMtable_size,
struct IM, memEM, MAX_INT);
}
init_entry(last_tag);
return last_tag;
}
static void checktag (int tag)
{
if (!(last_tag <= tag && tag <= 0))
luaL_verror("%d is not a valid tag", tag);
}
void luaI_realtag (int tag)
{
if (!(last_tag <= tag && tag < LUA_T_NIL))
luaL_verror("tag %d is not result of `newtag'", tag);
}
void luaI_settag (int tag, TObject *o)
{
luaI_realtag(tag);
switch (ttype(o)) {
case LUA_T_ARRAY:
o->value.a->htag = tag;
break;
default:
luaL_verror("cannot change the tag of a %s", luaI_typenames[-ttype(o)]);
}
}
int luaI_tag (TObject *o)
{
lua_Type t = ttype(o);
if (t == LUA_T_USERDATA)
return o->value.ts->tag;
else if (t == LUA_T_ARRAY)
return o->value.a->htag;
else return t;
}
TObject *luaI_getim (int tag, IMS event)
{
if (tag > LUA_T_USERDATA)
tag = LUA_T_USERDATA; /* default for non-registered tags */
return &luaI_IMtable[-tag].int_method[event];
}
void luaI_gettagmethod (void)
{
int t = (int)luaL_check_number(1);
int e = luaI_checkevent(luaL_check_string(2), luaI_eventname);
checktag(t);
if (validevent(t, e))
luaI_pushobject(&luaI_IMtable[-t].int_method[e]);
}
void luaI_settagmethod (void)
{
int t = (int)luaL_check_number(1);
int e = luaI_checkevent(luaL_check_string(2), luaI_eventname);
lua_Object func = lua_getparam(3);
checktag(t);
if (!validevent(t, e))
luaL_verror("cannot change internal method `%s' for tag %d",
luaI_eventname[e], t);
luaL_arg_check(lua_isnil(func) || lua_isfunction(func),
3, "function expected");
luaI_pushobject(&luaI_IMtable[-t].int_method[e]);
luaI_IMtable[-t].int_method[e] = *luaI_Address(func);
}
static TObject errorim = {LUA_T_NIL, {NULL}};
TObject *luaI_geterrorim (void)
{
return &errorim;
}
void luaI_seterrormethod (void)
{
lua_Object func = lua_getparam(1);
luaL_arg_check(lua_isnil(func) || lua_isfunction(func),
1, "function expected");
luaI_pushobject(&errorim);
errorim = *luaI_Address(func);
}
char *luaI_travfallbacks (int (*fn)(TObject *))
{
int e;
if (fn(&errorim))
return "error";
for (e=IM_GETTABLE; e<=IM_FUNCTION; e++) { /* ORDER IM */
int t;
for (t=0; t>=last_tag; t--)
if (fn(&luaI_IMtable[-t].int_method[e]))
return luaI_eventname[e];
}
return NULL;
}
/*
* ===================================================================
* compatibility with old fallback system
*/
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 (validevent(t, e))
luaI_IMtable[-t].int_method[e] = *func;
}
void luaI_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);
luaI_initfallbacks();
luaL_arg_check(lua_isfunction(func), 2, "function expected");
switch (luaI_findstring(name, oldnames)) {
case 0: /* old error fallback */
oldfunc = errorim;
errorim = *luaI_Address(func);
replace = errorFB;
break;
case 1: /* old getglobal fallback */
oldfunc = luaI_IMtable[-LUA_T_NIL].int_method[IM_GETGLOBAL];
luaI_IMtable[-LUA_T_NIL].int_method[IM_GETGLOBAL] = *luaI_Address(func);
replace = nilFB;
break;
case 2: { /* old arith fallback */
int i;
oldfunc = luaI_IMtable[-LUA_T_USERDATA].int_method[IM_POW];
for (i=IM_ADD; i<=IM_UNM; i++) /* ORDER IM */
fillvalids(i, luaI_Address(func));
replace = typeFB;
break;
}
case 3: { /* old order fallback */
int i;
oldfunc = luaI_IMtable[-LUA_T_USERDATA].int_method[IM_LT];
for (i=IM_LT; i<=IM_GE; i++) /* ORDER IM */
fillvalids(i, luaI_Address(func));
replace = typeFB;
break;
}
default: {
int e;
if ((e = luaI_findstring(name, luaI_eventname)) >= 0) {
oldfunc = luaI_IMtable[-LUA_T_USERDATA].int_method[e];
fillvalids(e, luaI_Address(func));
replace = (e == IM_GC || e == IM_INDEX) ? nilFB : typeFB;
}
else {
luaL_verror("`%s' is not a valid fallback name", name);
replace = NULL; /* to avoid warnings */
}
}
}
if (oldfunc.ttype != LUA_T_NIL)
luaI_pushobject(&oldfunc);
else
lua_pushcfunction(replace);
}