Lua 5.05.0

1 files changed, 38 insertions, 131 deletions

diff --git a/src/ltm.c b/src/ltm.c
index a20909a1..1b3e515e 100644
--- a/src/ltm.c
+++ b/src/ltm.c
@@ -1,163 +1,70 @@
 /*
-** $Id: ltm.c,v 1.56 2000/10/31 13:10:24 roberto Exp $
+** $Id: ltm.c,v 1.106 2003/04/03 13:35:34 roberto Exp $
 ** Tag methods
 ** See Copyright Notice in lua.h
 */
 
 
-#include <stdio.h>
 #include <string.h>
 
+#define ltm_c
+
 #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 char *const luaT_eventname[] = {  /* ORDER TM */
-  "gettable", "settable", "index", "getglobal", "setglobal", "add", "sub",
-  "mul", "div", "pow", "unm", "lt", "concat", "gc", "function",
-  "le", "gt", "ge",  /* deprecated options!! */
-  NULL
-};
-
-
-static int findevent (const 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 char *name, int t) {
-  int e = findevent(name);
-  if (e >= TM_N)
-    luaO_verror(L, "event `%.50s' is deprecated", name);
-  if (e == TM_GC && t == LUA_TTABLE)
-    luaO_verror(L, "event `gc' for tables is deprecated");
-  if (e < 0)
-    luaO_verror(L, "`%.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 char 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 */
+const char *const luaT_typenames[] = {
+  "nil", "boolean", "userdata", "number",
+  "string", "table", "function", "userdata", "thread"
 };
 
-int luaT_validevent (int t, int e) {  /* ORDER LUA_T */
-  return (t >= NUM_TAGS) ?  1 : luaT_validevents[t][e];
-}
-
-
-static void init_entry (lua_State *L, int tag) {
-  int i;
-  for (i=0; i<TM_N; i++)
-    luaT_gettm(L, tag, i) = NULL;
-  L->TMtable[tag].collected = NULL;
-}
-
 
 void luaT_init (lua_State *L) {
-  int t;
-  luaM_growvector(L, L->TMtable, 0, NUM_TAGS, struct TM, "", MAX_INT);
-  L->nblocks += NUM_TAGS*sizeof(struct TM);
-  L->last_tag = NUM_TAGS-1;
-  for (t=0; t<=L->last_tag; t++)
-    init_entry(L, t);
-}
-
-
-LUA_API int lua_newtag (lua_State *L) {
-  luaM_growvector(L, L->TMtable, L->last_tag, 1, struct TM,
-                  "tag table overflow", MAX_INT);
-  L->nblocks += sizeof(struct TM);
-  L->last_tag++;
-  init_entry(L, L->last_tag);
-  return L->last_tag;
-}
-
-
-static void checktag (lua_State *L, int tag) {
-  if (!(0 <= tag && tag <= L->last_tag))
-    luaO_verror(L, "%d is not a valid tag", tag);
-}
-
-void luaT_realtag (lua_State *L, int tag) {
-  if (!validtag(tag))
-    luaO_verror(L, "tag %d was not created by `newtag'", tag);
-}
-
-
-LUA_API int lua_copytagmethods (lua_State *L, int tagto, int tagfrom) {
-  int e;
-  checktag(L, tagto);
-  checktag(L, tagfrom);
-  for (e=0; e<TM_N; e++) {
-    if (luaT_validevent(tagto, e))
-      luaT_gettm(L, tagto, e) = luaT_gettm(L, tagfrom, e);
-  }
-  return tagto;
-}
-
-
-int luaT_tag (const TObject *o) {
-  int t = ttype(o);
-  switch (t) {
-    case LUA_TUSERDATA: return tsvalue(o)->u.d.tag;
-    case LUA_TTABLE:    return hvalue(o)->htag;
-    default:            return t;
+  static const char *const luaT_eventname[] = {  /* ORDER TM */
+    "__index", "__newindex",
+    "__gc", "__mode", "__eq",
+    "__add", "__sub", "__mul", "__div",
+    "__pow", "__unm", "__lt", "__le",
+    "__concat", "__call"
+  };
+  int i;
+  for (i=0; i<TM_N; i++) {
+    G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]);
+    luaS_fix(G(L)->tmname[i]);  /* never collect these names */
   }
 }
 
 
-LUA_API void lua_gettagmethod (lua_State *L, int t, const char *event) {
-  int e;
-  e = luaI_checkevent(L, event, t);
-  checktag(L, t);
-  if (luaT_validevent(t, e) && luaT_gettm(L, t, e)) {
-    clvalue(L->top) = luaT_gettm(L, t, e);
-    ttype(L->top) = LUA_TFUNCTION;
+/*
+** function to be used with macro "fasttm": optimized for absence of
+** tag methods
+*/
+const TObject *luaT_gettm (Table *events, TMS event, TString *ename) {
+  const TObject *tm = luaH_getstr(events, ename);
+  lua_assert(event <= TM_EQ);
+  if (ttisnil(tm)) {  /* no tag method? */
+    events->flags |= cast(lu_byte, 1u<<event);  /* cache this fact */
+    return NULL;
   }
-  else
-    ttype(L->top) = LUA_TNIL;
-  incr_top;
+  else return tm;
 }
 
 
-LUA_API void lua_settagmethod (lua_State *L, int t, const char *event) {
-  int e = luaI_checkevent(L, event, t);
-  checktag(L, t);
-  if (!luaT_validevent(t, e))
-    luaO_verror(L, "cannot change `%.20s' tag method for type `%.20s'%.20s",
-                luaT_eventname[e], luaO_typenames[t],
-                (t == LUA_TTABLE || t == LUA_TUSERDATA) ?
-                   " with default tag" : "");
-  switch (ttype(L->top - 1)) {
-    case LUA_TNIL:
-      luaT_gettm(L, t, e) = NULL;
-      break;
-    case LUA_TFUNCTION:
-      luaT_gettm(L, t, e) = clvalue(L->top - 1);
-      break;
+const TObject *luaT_gettmbyobj (lua_State *L, const TObject *o, TMS event) {
+  TString *ename = G(L)->tmname[event];
+  switch (ttype(o)) {
+    case LUA_TTABLE:
+      return luaH_getstr(hvalue(o)->metatable, ename);
+    case LUA_TUSERDATA:
+      return luaH_getstr(uvalue(o)->uv.metatable, ename);
     default:
-      lua_error(L, "tag method must be a function (or nil)");
+      return &luaO_nilobject;
   }
-  L->top--;
 }