ltm.c revision 1.10
1/* $NetBSD: ltm.c,v 1.10 2023/04/16 20:46:17 nikita Exp $ */ 2 3/* 4** Id: ltm.c 5** Tag methods 6** See Copyright Notice in lua.h 7*/ 8 9#define ltm_c 10#define LUA_CORE 11 12#include "lprefix.h" 13 14 15#ifndef _KERNEL 16#include <string.h> 17#endif /* _KERNEL */ 18 19#include "lua.h" 20 21#include "ldebug.h" 22#include "ldo.h" 23#include "lgc.h" 24#include "lobject.h" 25#include "lstate.h" 26#include "lstring.h" 27#include "ltable.h" 28#include "ltm.h" 29#include "lvm.h" 30 31 32static const char udatatypename[] = "userdata"; 33 34LUAI_DDEF const char *const luaT_typenames_[LUA_TOTALTYPES] = { 35 "no value", 36 "nil", "boolean", udatatypename, "number", 37 "string", "table", "function", udatatypename, "thread", 38 "upvalue", "proto" /* these last cases are used for tests only */ 39}; 40 41 42void luaT_init (lua_State *L) { 43 static const char *const luaT_eventname[] = { /* ORDER TM */ 44 "__index", "__newindex", 45 "__gc", "__mode", "__len", "__eq", 46#ifndef _KERNEL 47 "__add", "__sub", "__mul", "__mod", "__pow", 48 "__div", "__idiv", 49#else /* _KERNEL */ 50 "__add", "__sub", "__mul", "__mod", 51 "__idiv", 52#endif /* _KERNEL */ 53 "__band", "__bor", "__bxor", "__shl", "__shr", 54 "__unm", "__bnot", "__lt", "__le", 55 "__concat", "__call", "__close" 56 }; 57 int i; 58 for (i=0; i<TM_N; i++) { 59 G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]); 60 luaC_fix(L, obj2gco(G(L)->tmname[i])); /* never collect these names */ 61 } 62} 63 64 65/* 66** function to be used with macro "fasttm": optimized for absence of 67** tag methods 68*/ 69const TValue *luaT_gettm (Table *events, TMS event, TString *ename) { 70 const TValue *tm = luaH_getshortstr(events, ename); 71 lua_assert(event <= TM_EQ); 72 if (notm(tm)) { /* no tag method? */ 73 events->flags |= cast_byte(1u<<event); /* cache this fact */ 74 return NULL; 75 } 76 else return tm; 77} 78 79 80const TValue *luaT_gettmbyobj (lua_State *L, const TValue *o, TMS event) { 81 Table *mt; 82 switch (ttype(o)) { 83 case LUA_TTABLE: 84 mt = hvalue(o)->metatable; 85 break; 86 case LUA_TUSERDATA: 87 mt = uvalue(o)->metatable; 88 break; 89 default: 90 mt = G(L)->mt[ttype(o)]; 91 } 92 return (mt ? luaH_getshortstr(mt, G(L)->tmname[event]) : &G(L)->nilvalue); 93} 94 95 96/* 97** Return the name of the type of an object. For tables and userdata 98** with metatable, use their '__name' metafield, if present. 99*/ 100const char *luaT_objtypename (lua_State *L, const TValue *o) { 101 Table *mt; 102 if ((ttistable(o) && (mt = hvalue(o)->metatable) != NULL) || 103 (ttisfulluserdata(o) && (mt = uvalue(o)->metatable) != NULL)) { 104 const TValue *name = luaH_getshortstr(mt, luaS_new(L, "__name")); 105 if (ttisstring(name)) /* is '__name' a string? */ 106 return getstr(tsvalue(name)); /* use it as type name */ 107 } 108 return ttypename(ttype(o)); /* else use standard type name */ 109} 110 111 112void luaT_callTM (lua_State *L, const TValue *f, const TValue *p1, 113 const TValue *p2, const TValue *p3) { 114 StkId func = L->top; 115 setobj2s(L, func, f); /* push function (assume EXTRA_STACK) */ 116 setobj2s(L, func + 1, p1); /* 1st argument */ 117 setobj2s(L, func + 2, p2); /* 2nd argument */ 118 setobj2s(L, func + 3, p3); /* 3rd argument */ 119 L->top = func + 4; 120 /* metamethod may yield only when called from Lua code */ 121 if (isLuacode(L->ci)) 122 luaD_call(L, func, 0); 123 else 124 luaD_callnoyield(L, func, 0); 125} 126 127 128void luaT_callTMres (lua_State *L, const TValue *f, const TValue *p1, 129 const TValue *p2, StkId res) { 130 ptrdiff_t result = savestack(L, res); 131 StkId func = L->top; 132 setobj2s(L, func, f); /* push function (assume EXTRA_STACK) */ 133 setobj2s(L, func + 1, p1); /* 1st argument */ 134 setobj2s(L, func + 2, p2); /* 2nd argument */ 135 L->top += 3; 136 /* metamethod may yield only when called from Lua code */ 137 if (isLuacode(L->ci)) 138 luaD_call(L, func, 1); 139 else 140 luaD_callnoyield(L, func, 1); 141 res = restorestack(L, result); 142 setobjs2s(L, res, --L->top); /* move result to its place */ 143} 144 145 146static int callbinTM (lua_State *L, const TValue *p1, const TValue *p2, 147 StkId res, TMS event) { 148 const TValue *tm = luaT_gettmbyobj(L, p1, event); /* try first operand */ 149 if (notm(tm)) 150 tm = luaT_gettmbyobj(L, p2, event); /* try second operand */ 151 if (notm(tm)) return 0; 152 luaT_callTMres(L, tm, p1, p2, res); 153 return 1; 154} 155 156 157void luaT_trybinTM (lua_State *L, const TValue *p1, const TValue *p2, 158 StkId res, TMS event) { 159 if (l_unlikely(!callbinTM(L, p1, p2, res, event))) { 160 switch (event) { 161 case TM_BAND: case TM_BOR: case TM_BXOR: 162 case TM_SHL: case TM_SHR: case TM_BNOT: { 163 if (ttisnumber(p1) && ttisnumber(p2)) 164 luaG_tointerror(L, p1, p2); 165 else 166 luaG_opinterror(L, p1, p2, "perform bitwise operation on"); 167 } 168 /* calls never return, but to avoid warnings: *//* FALLTHROUGH */ 169 default: 170 luaG_opinterror(L, p1, p2, "perform arithmetic on"); 171 } 172 } 173} 174 175 176void luaT_tryconcatTM (lua_State *L) { 177 StkId top = L->top; 178 if (l_unlikely(!callbinTM(L, s2v(top - 2), s2v(top - 1), top - 2, 179 TM_CONCAT))) 180 luaG_concaterror(L, s2v(top - 2), s2v(top - 1)); 181} 182 183 184void luaT_trybinassocTM (lua_State *L, const TValue *p1, const TValue *p2, 185 int flip, StkId res, TMS event) { 186 if (flip) 187 luaT_trybinTM(L, p2, p1, res, event); 188 else 189 luaT_trybinTM(L, p1, p2, res, event); 190} 191 192 193void luaT_trybiniTM (lua_State *L, const TValue *p1, lua_Integer i2, 194 int flip, StkId res, TMS event) { 195 TValue aux; 196 setivalue(&aux, i2); 197 luaT_trybinassocTM(L, p1, &aux, flip, res, event); 198} 199 200 201/* 202** Calls an order tag method. 203** For lessequal, LUA_COMPAT_LT_LE keeps compatibility with old 204** behavior: if there is no '__le', try '__lt', based on l <= r iff 205** !(r < l) (assuming a total order). If the metamethod yields during 206** this substitution, the continuation has to know about it (to negate 207** the result of r<l); bit CIST_LEQ in the call status keeps that 208** information. 209*/ 210int luaT_callorderTM (lua_State *L, const TValue *p1, const TValue *p2, 211 TMS event) { 212 if (callbinTM(L, p1, p2, L->top, event)) /* try original event */ 213 return !l_isfalse(s2v(L->top)); 214#if defined(LUA_COMPAT_LT_LE) 215 else if (event == TM_LE) { 216 /* try '!(p2 < p1)' for '(p1 <= p2)' */ 217 L->ci->callstatus |= CIST_LEQ; /* mark it is doing 'lt' for 'le' */ 218 if (callbinTM(L, p2, p1, L->top, TM_LT)) { 219 L->ci->callstatus ^= CIST_LEQ; /* clear mark */ 220 return l_isfalse(s2v(L->top)); 221 } 222 /* else error will remove this 'ci'; no need to clear mark */ 223 } 224#endif 225 luaG_ordererror(L, p1, p2); /* no metamethod found */ 226 return 0; /* to avoid warnings */ 227} 228 229 230int luaT_callorderiTM (lua_State *L, const TValue *p1, int v2, 231 int flip, int isfloat, TMS event) { 232 TValue aux; const TValue *p2; 233#ifndef _KERNEL 234 if (isfloat) { 235 setfltvalue(&aux, cast_num(v2)); 236 } 237 else 238#endif /* _KERNEL */ 239 setivalue(&aux, v2); 240 if (flip) { /* arguments were exchanged? */ 241 p2 = p1; p1 = &aux; /* correct them */ 242 } 243 else 244 p2 = &aux; 245 return luaT_callorderTM(L, p1, p2, event); 246} 247 248 249void luaT_adjustvarargs (lua_State *L, int nfixparams, CallInfo *ci, 250 const Proto *p) { 251 int i; 252 int actual = cast_int(L->top - ci->func) - 1; /* number of arguments */ 253 int nextra = actual - nfixparams; /* number of extra arguments */ 254 ci->u.l.nextraargs = nextra; 255 luaD_checkstack(L, p->maxstacksize + 1); 256 /* copy function to the top of the stack */ 257 setobjs2s(L, L->top++, ci->func); 258 /* move fixed parameters to the top of the stack */ 259 for (i = 1; i <= nfixparams; i++) { 260 setobjs2s(L, L->top++, ci->func + i); 261 setnilvalue(s2v(ci->func + i)); /* erase original parameter (for GC) */ 262 } 263 ci->func += actual + 1; 264 ci->top += actual + 1; 265 lua_assert(L->top <= ci->top && ci->top <= L->stack_last); 266} 267 268 269void luaT_getvarargs (lua_State *L, CallInfo *ci, StkId where, int wanted) { 270 int i; 271 int nextra = ci->u.l.nextraargs; 272 if (wanted < 0) { 273 wanted = nextra; /* get all extra arguments available */ 274 checkstackGCp(L, nextra, where); /* ensure stack space */ 275 L->top = where + nextra; /* next instruction will need top */ 276 } 277 for (i = 0; i < wanted && i < nextra; i++) 278 setobjs2s(L, where + i, ci->func - nextra + i); 279 for (; i < wanted; i++) /* complete required results with nil */ 280 setnilvalue(s2v(where + i)); 281} 282 283