mirror of
https://github.com/lua/lua
synced 2024-12-11 21:44:01 +03:00
198 lines
4.9 KiB
C
198 lines
4.9 KiB
C
/*
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** $Id: ltm.c,v 1.73 2001/06/15 20:36:57 roberto Exp roberto $
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** Tag methods
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** See Copyright Notice in lua.h
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*/
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#include <stdio.h>
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#include <string.h>
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#define LUA_PRIVATE
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#include "lua.h"
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#include "ldo.h"
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#include "lmem.h"
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#include "lobject.h"
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#include "lstate.h"
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#include "lstring.h"
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#include "ltable.h"
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#include "ltm.h"
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const l_char *const luaT_eventname[] = { /* ORDER TM */
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l_s("gettable"), l_s("settable"), l_s("index"), l_s("getglobal"), l_s("setglobal"), l_s("add"), l_s("sub"),
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l_s("mul"), l_s("div"), l_s("pow"), l_s("unm"), l_s("lt"), l_s("concat"), l_s("gc"), l_s("function"),
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l_s("le"), l_s("gt"), l_s("ge"), /* deprecated options!! */
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NULL
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};
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static int findevent (const l_char *name) {
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int i;
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for (i=0; luaT_eventname[i]; i++)
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if (strcmp(luaT_eventname[i], name) == 0)
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return i;
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return -1; /* name not found */
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}
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static int luaI_checkevent (lua_State *L, const l_char *name, int t) {
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int e = findevent(name);
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if (e >= TM_N)
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luaO_verror(L, l_s("event `%.50s' is deprecated"), name);
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if (e == TM_GC && t == LUA_TTABLE)
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luaO_verror(L, l_s("event `gc' for tables is deprecated"));
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if (e < 0)
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luaO_verror(L, l_s("`%.50s' is not a valid event name"), name);
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return e;
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}
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/* events in LUA_TNIL are all allowed, since this is used as a
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* `placeholder' for default fallbacks
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*/
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/* ORDER LUA_T, ORDER TM */
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static const lu_byte luaT_validevents[NUM_TAGS][TM_N] = {
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{1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1}, /* LUA_TUSERDATA */
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{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, /* LUA_TNIL */
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{1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1}, /* LUA_TNUMBER */
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{1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, /* LUA_TSTRING */
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{0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1}, /* LUA_TTABLE */
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{1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0} /* LUA_TFUNCTION */
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};
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int luaT_validevent (int t, int e) { /* ORDER LUA_T */
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return (t >= NUM_TAGS) ? 1 : (int)luaT_validevents[t][e];
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}
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void luaT_init (lua_State *L) {
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static const l_char *const typenames[NUM_TAGS] = {
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l_s("userdata"), l_s("nil"), l_s("number"), l_s("string"),
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l_s("table"), l_s("function")
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};
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int i;
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for (i=0; i<NUM_TAGS; i++)
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luaT_newtag(L, typenames[i], i);
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}
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int luaT_newtag (lua_State *L, const l_char *name, int basictype) {
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int tag;
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int i;
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TString *ts;
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luaM_growvector(L, G(L)->TMtable, G(L)->ntag, G(L)->sizeTM, struct TM,
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MAX_INT, l_s("tag table overflow"));
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tag = G(L)->ntag;
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if (name == NULL)
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ts = NULL;
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else {
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TObject *v;
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ts = luaS_new(L, name);
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v = luaH_setstr(L, G(L)->type2tag, ts);
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if (ttype(v) != LUA_TNIL) return LUA_TNONE; /* invalid name */
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setnvalue(v, tag);
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}
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for (i=0; i<TM_N; i++)
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luaT_gettm(G(L), tag, i) = NULL;
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G(L)->TMtable[tag].collected = NULL;
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G(L)->TMtable[tag].name = ts;
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G(L)->TMtable[tag].basictype = basictype;
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G(L)->ntag++;
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return tag;
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}
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static void checktag (lua_State *L, int tag) {
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if (!(0 <= tag && tag < G(L)->ntag))
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luaO_verror(L, l_s("%d is not a valid tag"), tag);
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}
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LUA_API int lua_copytagmethods (lua_State *L, int tagto, int tagfrom) {
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int e;
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lua_lock(L);
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checktag(L, tagto);
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checktag(L, tagfrom);
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for (e=0; e<TM_N; e++) {
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if (luaT_validevent(tagto, e))
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luaT_gettm(G(L), tagto, e) = luaT_gettm(G(L), tagfrom, e);
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}
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lua_unlock(L);
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return tagto;
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}
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int luaT_tag (const TObject *o) {
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int t = ttype(o);
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switch (t) {
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case LUA_TUSERDATA: return uvalue(o)->uv.tag;
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case LUA_TTABLE: return hvalue(o)->htag;
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default: return t;
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}
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}
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const l_char *luaT_typename (global_State *G, const TObject *o) {
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int t = ttype(o);
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int tag;
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TString *ts;
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switch (t) {
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case LUA_TUSERDATA:
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tag = uvalue(o)->uv.tag;
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break;
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case LUA_TTABLE:
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tag = hvalue(o)->htag;
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break;
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default:
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tag = t;
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}
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ts = G->TMtable[tag].name;
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if (ts == NULL)
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ts = G->TMtable[t].name;
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return getstr(ts);
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}
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LUA_API void lua_gettagmethod (lua_State *L, int t, const l_char *event) {
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int e;
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lua_lock(L);
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e = luaI_checkevent(L, event, t);
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checktag(L, t);
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if (luaT_validevent(t, e) && luaT_gettm(G(L), t, e)) {
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setclvalue(L->top, luaT_gettm(G(L), t, e));
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}
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else
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setnilvalue(L->top);
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incr_top;
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lua_unlock(L);
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}
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LUA_API void lua_settagmethod (lua_State *L, int t, const l_char *event) {
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int e;
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lua_lock(L);
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e = luaI_checkevent(L, event, t);
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checktag(L, t);
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if (!luaT_validevent(t, e))
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luaO_verror(L, l_s("cannot change `%.20s' tag method for type `%.20s'%.20s"),
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luaT_eventname[e], typenamebytag(G(L), t),
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(t == LUA_TTABLE || t == LUA_TUSERDATA) ?
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l_s(" with default tag") : l_s(""));
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switch (ttype(L->top - 1)) {
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case LUA_TNIL:
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luaT_gettm(G(L), t, e) = NULL;
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break;
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case LUA_TFUNCTION:
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luaT_gettm(G(L), t, e) = clvalue(L->top - 1);
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break;
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default:
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luaD_error(L, l_s("tag method must be a function (or nil)"));
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}
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L->top--;
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lua_unlock(L);
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}
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