diff options
Diffstat (limited to 'src/lua/ltm.c')
| -rw-r--r-- | src/lua/ltm.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/src/lua/ltm.c b/src/lua/ltm.c new file mode 100644 index 0000000..ee77a16 --- /dev/null +++ b/src/lua/ltm.c @@ -0,0 +1,165 @@ +/* +** $Id: ltm.c,v 2.38.1.1 2017/04/19 17:39:34 roberto Exp $ +** Tag methods +** See Copyright Notice in lua.h +*/ + +#define ltm_c +#define LUA_CORE + +#include "lprefix.h" + + +#include "string.h" + +#include "lua.h" + +#include "ldebug.h" +#include "ldo.h" +#include "lobject.h" +#include "lstate.h" +#include "lstring.h" +#include "ltable.h" +#include "ltm.h" +#include "lvm.h" + + +static const char udatatypename[] = "userdata"; + +LUAI_DDEF const char *const luaT_typenames_[LUA_TOTALTAGS] = { + "no value", + "nil", "boolean", udatatypename, "number", + "string", "table", "function", udatatypename, "thread", + "proto" /* this last case is used for tests only */ +}; + + +void luaT_init (lua_State *L) { + static const char *const luaT_eventname[] = { /* ORDER TM */ + "__index", "__newindex", + "__gc", "__mode", "__len", "__eq", + "__add", "__sub", "__mul", "__mod", "__pow", + "__div", "__idiv", + "__band", "__bor", "__bxor", "__shl", "__shr", + "__unm", "__bnot", "__lt", "__le", + "__concat", "__call" + }; + int i; + for (i=0; i<TM_N; i++) { + G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]); + luaC_fix(L, obj2gco(G(L)->tmname[i])); /* never collect these names */ + } +} + + +/* +** function to be used with macro "fasttm": optimized for absence of +** tag methods +*/ +const TValue *luaT_gettm (Table *events, TMS event, TString *ename) { + const TValue *tm = luaH_getshortstr(events, ename); + lua_assert(event <= TM_EQ); + if (ttisnil(tm)) { /* no tag method? */ + events->flags |= cast_byte(1u<<event); /* cache this fact */ + return NULL; + } + else return tm; +} + + +const TValue *luaT_gettmbyobj (lua_State *L, const TValue *o, TMS event) { + Table *mt; + switch (ttnov(o)) { + case LUA_TTABLE: + mt = hvalue(o)->metatable; + break; + case LUA_TUSERDATA: + mt = uvalue(o)->metatable; + break; + default: + mt = G(L)->mt[ttnov(o)]; + } + return (mt ? luaH_getshortstr(mt, G(L)->tmname[event]) : luaO_nilobject); +} + + +/* +** Return the name of the type of an object. For tables and userdata +** with metatable, use their '__name' metafield, if present. +*/ +const char *luaT_objtypename (lua_State *L, const TValue *o) { + Table *mt; + if ((ttistable(o) && (mt = hvalue(o)->metatable) != NULL) || + (ttisfulluserdata(o) && (mt = uvalue(o)->metatable) != NULL)) { + const TValue *name = luaH_getshortstr(mt, luaS_new(L, "__name")); + if (ttisstring(name)) /* is '__name' a string? */ + return getstr(tsvalue(name)); /* use it as type name */ + } + return ttypename(ttnov(o)); /* else use standard type name */ +} + + +void luaT_callTM (lua_State *L, const TValue *f, const TValue *p1, + const TValue *p2, TValue *p3, int hasres) { + ptrdiff_t result = savestack(L, p3); + StkId func = L->top; + setobj2s(L, func, f); /* push function (assume EXTRA_STACK) */ + setobj2s(L, func + 1, p1); /* 1st argument */ + setobj2s(L, func + 2, p2); /* 2nd argument */ + L->top += 3; + if (!hasres) /* no result? 'p3' is third argument */ + setobj2s(L, L->top++, p3); /* 3rd argument */ + /* metamethod may yield only when called from Lua code */ + if (isLua(L->ci)) + luaD_call(L, func, hasres); + else + luaD_callnoyield(L, func, hasres); + if (hasres) { /* if has result, move it to its place */ + p3 = restorestack(L, result); + setobjs2s(L, p3, --L->top); + } +} + + +int luaT_callbinTM (lua_State *L, const TValue *p1, const TValue *p2, + StkId res, TMS event) { + const TValue *tm = luaT_gettmbyobj(L, p1, event); /* try first operand */ + if (ttisnil(tm)) + tm = luaT_gettmbyobj(L, p2, event); /* try second operand */ + if (ttisnil(tm)) return 0; + luaT_callTM(L, tm, p1, p2, res, 1); + return 1; +} + + +void luaT_trybinTM (lua_State *L, const TValue *p1, const TValue *p2, + StkId res, TMS event) { + if (!luaT_callbinTM(L, p1, p2, res, event)) { + switch (event) { + case TM_CONCAT: + luaG_concaterror(L, p1, p2); + /* call never returns, but to avoid warnings: *//* FALLTHROUGH */ + case TM_BAND: case TM_BOR: case TM_BXOR: + case TM_SHL: case TM_SHR: case TM_BNOT: { + lua_Number dummy; + if (tonumber(p1, &dummy) && tonumber(p2, &dummy)) + luaG_tointerror(L, p1, p2); + else + luaG_opinterror(L, p1, p2, "perform bitwise operation on"); + } + /* calls never return, but to avoid warnings: *//* FALLTHROUGH */ + default: + luaG_opinterror(L, p1, p2, "perform arithmetic on"); + } + } +} + + +int luaT_callorderTM (lua_State *L, const TValue *p1, const TValue *p2, + TMS event) { + if (!luaT_callbinTM(L, p1, p2, L->top, event)) + return -1; /* no metamethod */ + else + return !l_isfalse(L->top); +} + |