| /* |
| ** $Id: ltm.c,v 1.75 2001/07/23 19:56:00 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"), |
| 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 e = findevent(name); |
| 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 = NULL; |
| 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) { |
| TObject *v; |
| ts = luaS_new(L, name); |
| v = luaH_setstr(L, G(L)->type2tag, ts); |
| if (ttype(v) == LUA_TNUMBER) return (int)nvalue(v); |
| 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 uvalue(o)->uv.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 = uvalue(o)->uv.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); |
| 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); |
| 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], typenamebytag(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); |
| } |
| |