client/deps/liblua/ltm.c

   1 /*
   2 ** $Id: ltm.c,v 2.14 2011/06/02 19:31:40 roberto Exp $
   3 ** Tag methods
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8 #include <string.h>
   9
  10 #define ltm_c
  11 #define LUA_CORE
  12
  13 #include "lua.h"
  14
  15 #include "lobject.h"
  16 #include "lstate.h"
  17 #include "lstring.h"
  18 #include "ltable.h"
  19 #include "ltm.h"
  20
  21
  22 static const char udatatypename[] = "userdata";
  23
  24 LUAI_DDEF const char *const luaT_typenames_[LUA_TOTALTAGS] = {
  25     "no value",
  26     "nil", "boolean", udatatypename, "number",
  27     "string", "table", "function", udatatypename, "thread",
  28     "proto", "upval"  /* these last two cases are used for tests only */
  29 };
  30
  31
  32 void luaT_init(lua_State *L) {
  33     static const char *const luaT_eventname[] = {  /* ORDER TM */
  34         "__index", "__newindex",
  35         "__gc", "__mode", "__len", "__eq",
  36         "__add", "__sub", "__mul", "__div", "__mod",
  37         "__pow", "__unm", "__lt", "__le",
  38         "__concat", "__call"
  39     };
  40     int i;
  41     for (i = 0; i < TM_N; i++) {
  42         G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]);
  43         luaS_fix(G(L)->tmname[i]);  /* never collect these names */
  44     }
  45 }
  46
  47
  48 /*
  49 ** function to be used with macro "fasttm": optimized for absence of
  50 ** tag methods
  51 */
  52 const TValue *luaT_gettm(Table *events, TMS event, TString *ename) {
  53     const TValue *tm = luaH_getstr(events, ename);
  54     lua_assert(event <= TM_EQ);
  55     if (ttisnil(tm)) {  /* no tag method? */
  56         events->flags |= cast_byte(1u << event); /* cache this fact */
  57         return NULL;
  58     } else return tm;
  59 }
  60
  61
  62 const TValue *luaT_gettmbyobj(lua_State *L, const TValue *o, TMS event) {
  63     Table *mt;
  64     switch (ttypenv(o)) {
  65         case LUA_TTABLE:
  66             mt = hvalue(o)->metatable;
  67             break;
  68         case LUA_TUSERDATA:
  69             mt = uvalue(o)->metatable;
  70             break;
  71         default:
  72             mt = G(L)->mt[ttypenv(o)];
  73     }
  74     return (mt ? luaH_getstr(mt, G(L)->tmname[event]) : luaO_nilobject);
  75 }
  76