client/deps/liblua/ltm.c

   1 /*
   2 ** $Id: ltm.c $
   3 ** Tag methods
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7 #define ltm_c
   8 #define LUA_CORE
   9
  10 #include "lprefix.h"
  11
  12
  13 #include <string.h>
  14
  15 #include "lua.h"
  16
  17 #include "ldebug.h"
  18 #include "ldo.h"
  19 #include "lgc.h"
  20 #include "lobject.h"
  21 #include "lstate.h"
  22 #include "lstring.h"
  23 #include "ltable.h"
  24 #include "ltm.h"
  25 #include "lvm.h"
  26
  27
  28 static const char udatatypename[] = "userdata";
  29
  30 LUAI_DDEF const char *const luaT_typenames_[LUA_TOTALTYPES] = {
  31     "no value",
  32     "nil", "boolean", udatatypename, "number",
  33     "string", "table", "function", udatatypename, "thread",
  34     "upvalue", "proto" /* these last cases are used for tests only */
  35 };
  36
  37
  38 void luaT_init(lua_State *L) {
  39     static const char *const luaT_eventname[] = {  /* ORDER TM */
  40         "__index", "__newindex",
  41         "__gc", "__mode", "__len", "__eq",
  42         "__add", "__sub", "__mul", "__mod", "__pow",
  43         "__div", "__idiv",
  44         "__band", "__bor", "__bxor", "__shl", "__shr",
  45         "__unm", "__bnot", "__lt", "__le",
  46         "__concat", "__call", "__close"
  47     };
  48     int i;
  49     for (i = 0; i < TM_N; i++) {
  50         G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]);
  51         luaC_fix(L, obj2gco(G(L)->tmname[i]));  /* never collect these names */
  52     }
  53 }
  54
  55
  56 /*
  57 ** function to be used with macro "fasttm": optimized for absence of
  58 ** tag methods
  59 */
  60 const TValue *luaT_gettm(Table *events, TMS event, TString *ename) {
  61     const TValue *tm = luaH_getshortstr(events, ename);
  62     lua_assert(event <= TM_EQ);
  63     if (notm(tm)) {  /* no tag method? */
  64         events->flags |= cast_byte(1u << event); /* cache this fact */
  65         return NULL;
  66     } else return tm;
  67 }
  68
  69
  70 const TValue *luaT_gettmbyobj(lua_State *L, const TValue *o, TMS event) {
  71     Table *mt;
  72     switch (ttype(o)) {
  73         case LUA_TTABLE:
  74             mt = hvalue(o)->metatable;
  75             break;
  76         case LUA_TUSERDATA:
  77             mt = uvalue(o)->metatable;
  78             break;
  79         default:
  80             mt = G(L)->mt[ttype(o)];
  81     }
  82     return (mt ? luaH_getshortstr(mt, G(L)->tmname[event]) : &G(L)->nilvalue);
  83 }
  84
  85
  86 /*
  87 ** Return the name of the type of an object. For tables and userdata
  88 ** with metatable, use their '__name' metafield, if present.
  89 */
  90 const char *luaT_objtypename(lua_State *L, const TValue *o) {
  91     Table *mt;
  92     if ((ttistable(o) && (mt = hvalue(o)->metatable) != NULL) ||
  93             (ttisfulluserdata(o) && (mt = uvalue(o)->metatable) != NULL)) {
  94         const TValue *name = luaH_getshortstr(mt, luaS_new(L, "__name"));
  95         if (ttisstring(name))  /* is '__name' a string? */
  96             return getstr(tsvalue(name));  /* use it as type name */
  97     }
  98     return ttypename(ttype(o));  /* else use standard type name */
  99 }
 100
 101
 102 void luaT_callTM(lua_State *L, const TValue *f, const TValue *p1,
 103                  const TValue *p2, const TValue *p3) {
 104     StkId func = L->top.p;
 105     setobj2s(L, func, f);  /* push function (assume EXTRA_STACK) */
 106     setobj2s(L, func + 1, p1);  /* 1st argument */
 107     setobj2s(L, func + 2, p2);  /* 2nd argument */
 108     setobj2s(L, func + 3, p3);  /* 3rd argument */
 109     L->top.p = func + 4;
 110     /* metamethod may yield only when called from Lua code */
 111     if (isLuacode(L->ci))
 112         luaD_call(L, func, 0);
 113     else
 114         luaD_callnoyield(L, func, 0);
 115 }
 116
 117
 118 void luaT_callTMres(lua_State *L, const TValue *f, const TValue *p1,
 119                     const TValue *p2, StkId res) {
 120     ptrdiff_t result = savestack(L, res);
 121     StkId func = L->top.p;
 122     setobj2s(L, func, f);  /* push function (assume EXTRA_STACK) */
 123     setobj2s(L, func + 1, p1);  /* 1st argument */
 124     setobj2s(L, func + 2, p2);  /* 2nd argument */
 125     L->top.p += 3;
 126     /* metamethod may yield only when called from Lua code */
 127     if (isLuacode(L->ci))
 128         luaD_call(L, func, 1);
 129     else
 130         luaD_callnoyield(L, func, 1);
 131     res = restorestack(L, result);
 132     setobjs2s(L, res, --L->top.p);  /* move result to its place */
 133 }
 134
 135
 136 static int callbinTM(lua_State *L, const TValue *p1, const TValue *p2,
 137                      StkId res, TMS event) {
 138     const TValue *tm = luaT_gettmbyobj(L, p1, event);  /* try first operand */
 139     if (notm(tm))
 140         tm = luaT_gettmbyobj(L, p2, event);  /* try second operand */
 141     if (notm(tm)) return 0;
 142     luaT_callTMres(L, tm, p1, p2, res);
 143     return 1;
 144 }
 145
 146
 147 void luaT_trybinTM(lua_State *L, const TValue *p1, const TValue *p2,
 148                    StkId res, TMS event) {
 149     if (l_unlikely(!callbinTM(L, p1, p2, res, event))) {
 150         switch (event) {
 151             case TM_BAND:
 152             case TM_BOR:
 153             case TM_BXOR:
 154             case TM_SHL:
 155             case TM_SHR:
 156             case TM_BNOT: {
 157                 if (ttisnumber(p1) && ttisnumber(p2))
 158                     luaG_tointerror(L, p1, p2);
 159                 else
 160                     luaG_opinterror(L, p1, p2, "perform bitwise operation on");
 161             }
 162                 /* calls never return, but to avoid warnings: *//* FALLTHROUGH */
 163             default:
 164                 luaG_opinterror(L, p1, p2, "perform arithmetic on");
 165         }
 166     }
 167 }
 168
 169
 170 void luaT_tryconcatTM(lua_State *L) {
 171     StkId top = L->top.p;
 172     if (l_unlikely(!callbinTM(L, s2v(top - 2), s2v(top - 1), top - 2,
 173                               TM_CONCAT)))
 174         luaG_concaterror(L, s2v(top - 2), s2v(top - 1));
 175 }
 176
 177
 178 void luaT_trybinassocTM(lua_State *L, const TValue *p1, const TValue *p2,
 179                         int flip, StkId res, TMS event) {
 180     if (flip)
 181         luaT_trybinTM(L, p2, p1, res, event);
 182     else
 183         luaT_trybinTM(L, p1, p2, res, event);
 184 }
 185
 186
 187 void luaT_trybiniTM(lua_State *L, const TValue *p1, lua_Integer i2,
 188                     int flip, StkId res, TMS event) {
 189     TValue aux;
 190     setivalue(&aux, i2);
 191     luaT_trybinassocTM(L, p1, &aux, flip, res, event);
 192 }
 193
 194
 195 /*
 196 ** Calls an order tag method.
 197 ** For lessequal, LUA_COMPAT_LT_LE keeps compatibility with old
 198 ** behavior: if there is no '__le', try '__lt', based on l <= r iff
 199 ** !(r < l) (assuming a total order). If the metamethod yields during
 200 ** this substitution, the continuation has to know about it (to negate
 201 ** the result of r<l); bit CIST_LEQ in the call status keeps that
 202 ** information.
 203 */
 204 int luaT_callorderTM(lua_State *L, const TValue *p1, const TValue *p2,
 205                      TMS event) {
 206     if (callbinTM(L, p1, p2, L->top.p, event))  /* try original event */
 207         return !l_isfalse(s2v(L->top.p));
 208 #if defined(LUA_COMPAT_LT_LE)
 209     else if (event == TM_LE) {
 210         /* try '!(p2 < p1)' for '(p1 <= p2)' */
 211         L->ci->callstatus |= CIST_LEQ;  /* mark it is doing 'lt' for 'le' */
 212         if (callbinTM(L, p2, p1, L->top.p, TM_LT)) {
 213             L->ci->callstatus ^= CIST_LEQ;  /* clear mark */
 214             return l_isfalse(s2v(L->top.p));
 215         }
 216         /* else error will remove this 'ci'; no need to clear mark */
 217     }
 218 #endif
 219     luaG_ordererror(L, p1, p2);  /* no metamethod found */
 220     return 0;  /* to avoid warnings */
 221 }
 222
 223
 224 int luaT_callorderiTM(lua_State *L, const TValue *p1, int v2,
 225                       int flip, int isfloat, TMS event) {
 226     TValue aux;
 227     const TValue *p2;
 228     if (isfloat) {
 229         setfltvalue(&aux, cast_num(v2));
 230     } else
 231         setivalue(&aux, v2);
 232     if (flip) {  /* arguments were exchanged? */
 233         p2 = p1;
 234         p1 = &aux;  /* correct them */
 235     } else
 236         p2 = &aux;
 237     return luaT_callorderTM(L, p1, p2, event);
 238 }
 239
 240
 241 void luaT_adjustvarargs(lua_State *L, int nfixparams, CallInfo *ci,
 242                         const Proto *p) {
 243     int i;
 244     int actual = cast_int(L->top.p - ci->func.p) - 1;  /* number of arguments */
 245     int nextra = actual - nfixparams;  /* number of extra arguments */
 246     ci->u.l.nextraargs = nextra;
 247     luaD_checkstack(L, p->maxstacksize + 1);
 248     /* copy function to the top of the stack */
 249     setobjs2s(L, L->top.p++, ci->func.p);
 250     /* move fixed parameters to the top of the stack */
 251     for (i = 1; i <= nfixparams; i++) {
 252         setobjs2s(L, L->top.p++, ci->func.p + i);
 253         setnilvalue(s2v(ci->func.p + i));  /* erase original parameter (for GC) */
 254     }
 255     ci->func.p += actual + 1;
 256     ci->top.p += actual + 1;
 257     lua_assert(L->top.p <= ci->top.p && ci->top.p <= L->stack_last.p);
 258 }
 259
 260
 261 void luaT_getvarargs(lua_State *L, CallInfo *ci, StkId where, int wanted) {
 262     int i;
 263     int nextra = ci->u.l.nextraargs;
 264     if (wanted < 0) {
 265         wanted = nextra;  /* get all extra arguments available */
 266         checkstackGCp(L, nextra, where);  /* ensure stack space */
 267         L->top.p = where + nextra;  /* next instruction will need top */
 268     }
 269     for (i = 0; i < wanted && i < nextra; i++)
 270         setobjs2s(L, where + i, ci->func.p - nextra + i);
 271     for (; i < wanted; i++)   /* complete required results with nil */
 272         setnilvalue(s2v(where + i));
 273 }
 274