1 | /* |
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2 | ** $Id: ltm.c,v 2.8.1.1 2007/12/27 13:02:25 roberto Exp $ |
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3 | ** Tag methods |
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4 | ** See Copyright Notice in lua.h |
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5 | */ |
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6 | |
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7 | |
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8 | #include <string.h> |
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9 | |
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10 | #define ltm_c |
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11 | #define LUA_CORE |
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12 | |
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13 | #include "lua.h" |
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14 | |
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15 | #include "lobject.h" |
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16 | #include "lstate.h" |
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17 | #include "lstring.h" |
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18 | #include "ltable.h" |
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19 | #include "ltm.h" |
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20 | |
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21 | |
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22 | |
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23 | const char *const luaT_typenames[] = { |
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24 | "nil", "boolean", "userdata", "number", |
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25 | "string", "table", "function", "userdata", "thread", |
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26 | "proto", "upval" |
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27 | }; |
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28 | |
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29 | |
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30 | void luaT_init (lua_State *L) { |
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31 | static const char *const luaT_eventname[] = { /* ORDER TM */ |
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32 | "__index", "__newindex", |
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33 | "__gc", "__mode", "__eq", |
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34 | "__add", "__sub", "__mul", "__div", "__mod", |
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35 | "__pow", "__unm", "__len", "__lt", "__le", |
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36 | "__concat", "__call" |
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37 | }; |
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38 | int i; |
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39 | for (i=0; i<TM_N; i++) { |
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40 | G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]); |
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41 | luaS_fix(G(L)->tmname[i]); /* never collect these names */ |
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42 | } |
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43 | } |
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44 | |
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45 | |
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46 | /* |
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47 | ** function to be used with macro "fasttm": optimized for absence of |
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48 | ** tag methods |
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49 | */ |
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50 | const TValue *luaT_gettm (Table *events, TMS event, TString *ename) { |
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51 | const TValue *tm = luaH_getstr(events, ename); |
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52 | lua_assert(event <= TM_EQ); |
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53 | if (ttisnil(tm)) { /* no tag method? */ |
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54 | events->flags |= cast_byte(1u<<event); /* cache this fact */ |
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55 | return NULL; |
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56 | } |
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57 | else return tm; |
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58 | } |
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59 | |
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60 | |
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61 | const TValue *luaT_gettmbyobj (lua_State *L, const TValue *o, TMS event) { |
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62 | Table *mt; |
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63 | switch (ttype(o)) { |
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64 | case LUA_TTABLE: |
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65 | mt = hvalue(o)->metatable; |
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66 | break; |
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67 | case LUA_TUSERDATA: |
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68 | mt = uvalue(o)->metatable; |
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69 | break; |
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70 | default: |
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71 | mt = G(L)->mt[ttype(o)]; |
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72 | } |
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73 | return (mt ? luaH_getstr(mt, G(L)->tmname[event]) : luaO_nilobject); |
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74 | } |
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75 | |
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