lua/fallback.c

290 lines
6.3 KiB
C

/*
** fallback.c
** TecCGraf - PUC-Rio
*/
char *rcs_fallback="$Id: fallback.c,v 1.26 1997/02/26 17:38:41 roberto Unstable roberto $";
#include <stdio.h>
#include <string.h>
#include "mem.h"
#include "fallback.h"
#include "opcode.h"
#include "lua.h"
#include "table.h"
#include "tree.h"
#include "hash.h"
static void errorFB (void);
static void indexFB (void);
static void gettableFB (void);
static void arithFB (void);
static void concatFB (void);
static void orderFB (void);
static void GDFB (void);
static void funcFB (void);
/*
** Warning: This list must be in the same order as the #define's
*/
struct FB luaI_fallBacks[] = {
{"gettable", {LUA_T_CFUNCTION, {gettableFB}}, 2, 1},
{"arith", {LUA_T_CFUNCTION, {arithFB}}, 3, 1},
{"order", {LUA_T_CFUNCTION, {orderFB}}, 3, 1},
{"concat", {LUA_T_CFUNCTION, {concatFB}}, 2, 1},
{"settable", {LUA_T_CFUNCTION, {gettableFB}}, 3, 0},
{"gc", {LUA_T_CFUNCTION, {GDFB}}, 1, 0},
{"function", {LUA_T_CFUNCTION, {funcFB}}, -1, -1},
/* no fixed number of params or results */
{"getglobal", {LUA_T_CFUNCTION, {indexFB}}, 1, 1},
/* same default behavior of index FB */
{"index", {LUA_T_CFUNCTION, {indexFB}}, 2, 1},
{"error", {LUA_T_CFUNCTION, {errorFB}}, 1, 0}
};
#define N_FB (sizeof(luaI_fallBacks)/sizeof(struct FB))
static int luaI_findevent (char *name)
{
int i;
for (i=0; i<N_FB; i++)
if (strcmp(luaI_fallBacks[i].kind, name) == 0)
return i;
/* name not found */
lua_error("invalid event name");
return 0; /* to avoid warnings */
}
void luaI_setfallback (void)
{
int i;
char *name = lua_getstring(lua_getparam(1));
lua_Object func = lua_getparam(2);
if (name == NULL || !lua_isfunction(func))
lua_error("incorrect argument to function `setfallback'");
i = luaI_findevent(name);
luaI_pushobject(&luaI_fallBacks[i].function);
luaI_fallBacks[i].function = *luaI_Address(func);
}
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 indexFB (void)
{
lua_pushnil();
}
static void gettableFB (void)
{
lua_error("indexed expression not a table");
}
static void arithFB (void)
{
lua_error("unexpected type at conversion to number");
}
static void concatFB (void)
{
lua_error("unexpected type at conversion to string");
}
static void orderFB (void)
{
lua_error("unexpected type at comparison");
}
static void GDFB (void) { }
static void funcFB (void)
{
lua_error("call expression not a function");
}
/* -------------------------------------------
** Reference routines
*/
static struct ref {
Object o;
enum {LOCK, HOLD, FREE, COLLECTED} status;
} *refArray = NULL;
static int refSize = 0;
int luaI_ref (Object *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;
}
Object *luaI_getref (int ref)
{
static Object 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)(Object *))
{
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;
}
char *luaI_travfallbacks (int (*fn)(Object *))
{
int i;
for (i=0; i<N_FB; i++)
if (fn(&luaI_fallBacks[i].function))
return luaI_fallBacks[i].kind;
return NULL;
}
/* -------------------------------------------
* Internal Methods
*/
#define BASE_TAG 1000
static struct IM {
lua_Type tp;
Object int_method[FB_N];
} *luaI_IMtable = NULL;
static int IMtable_size = 0;
static int last_tag = BASE_TAG-1;
int lua_newtag (char *t)
{
int i;
++last_tag;
if ((last_tag-BASE_TAG) >= IMtable_size)
IMtable_size = growvector(&luaI_IMtable, IMtable_size,
struct IM, memEM, MAX_INT);
if (strcmp(t, "table") == 0)
luaI_IMtable[last_tag-BASE_TAG].tp = LUA_T_ARRAY;
else if (strcmp(t, "userdata") == 0)
luaI_IMtable[last_tag-BASE_TAG].tp = LUA_T_USERDATA;
else
lua_error("invalid type for new tag");
for (i=0; i<FB_N; i++)
luaI_IMtable[last_tag-BASE_TAG].int_method[i].ttype = LUA_T_NIL;
return last_tag;
}
static int validtag (int tag)
{
return (BASE_TAG <= tag && tag <= last_tag);
}
static void checktag (int tag)
{
if (!validtag(tag))
lua_error("invalid tag");
}
void luaI_settag (int tag, Object *o)
{
checktag(tag);
if (ttype(o) != luaI_IMtable[tag-BASE_TAG].tp)
lua_error("Tag is not compatible with this type");
if (o->ttype == LUA_T_ARRAY)
o->value.a->htag = tag;
else /* must be userdata */
o->value.ts->tag = tag;
}
int luaI_tag (Object *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;
}
Object *luaI_getim (int tag, int event)
{
if (tag == 0)
return &luaI_fallBacks[event].function;
else if (validtag(tag)) {
Object *func = &luaI_IMtable[tag-BASE_TAG].int_method[event];
if (func->ttype == LUA_T_NIL)
return NULL;
else
return func;
}
else return NULL;
}
void luaI_setintmethod (void)
{
lua_Object tag = lua_getparam(1);
lua_Object event = lua_getparam(2);
lua_Object func = lua_getparam(3);
if (!(lua_isnumber(tag) && lua_isstring(event) && lua_isfunction(func)))
lua_error("incorrect arguments to function `setintmethod'");
else {
int i = luaI_findevent(lua_getstring(event));
int t = lua_getnumber(tag);
checktag(t);
luaI_IMtable[t-BASE_TAG].int_method[i] = *luaI_Address(func);
}
}