getsize.c

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/* lua-getsize
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   Author: (C) 2009 Matthew Wild
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   License: MIT/X11 license
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   Description: Adds a debug.getsize() function which
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                returns the size in bytes of a Lua object
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*/
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#include <stdio.h>
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#include <lua.h>
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#include <lstate.h>
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#include <lobject.h>
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#include <lfunc.h>
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int debug_getsize(lua_State* L)
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{
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  TValue* o = L->base;
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  switch (o->tt) {
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    /* Container types */
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    case LUA_TTABLE: {
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      Table *h = hvalue(o);
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      lua_pushinteger(L, sizeof(Table) + sizeof(TValue) * h->sizearray +
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                             sizeof(Node) * sizenode(h));
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      break;
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    }
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    case LUA_TFUNCTION: {
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      Closure *cl = clvalue(o);
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      lua_pushinteger(L, (cl->c.isC) ? sizeCclosure(cl->c.nupvalues) :
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                           sizeLclosure(cl->l.nupvalues));
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      break;
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    }
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    case LUA_TTHREAD: {
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      lua_State *th = thvalue(o);
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      lua_pushinteger(L, sizeof(lua_State) + sizeof(TValue) * th->stacksize +
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                                 sizeof(CallInfo) * th->size_ci);
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      break;
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    }
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    case LUA_TPROTO: {
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      Proto *p = pvalue(o);
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      lua_pushinteger(L, sizeof(Proto) + sizeof(Instruction) * p->sizecode +
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                             sizeof(Proto *) * p->sizep +
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                             sizeof(TValue) * p->sizek +
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                             sizeof(int) * p->sizelineinfo +
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                             sizeof(LocVar) * p->sizelocvars +
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                             sizeof(TString *) * p->sizeupvalues);
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     break;
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    }
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    /* Non-containers */
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    case LUA_TUSERDATA: {
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      lua_pushnumber(L, uvalue(o)->len);
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      break;
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    }
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    case LUA_TLIGHTUSERDATA: {
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      lua_pushnumber(L, sizeof(void*));
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      break;
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    }
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    case LUA_TSTRING: {
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      TString *s = rawtsvalue(o);
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      lua_pushinteger(L, sizeof(TString) + s->tsv.len + 1);
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      break;
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    }
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    case LUA_TNUMBER: {
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      lua_pushinteger(L, sizeof(lua_Number));
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      break;
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    }
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    case LUA_TBOOLEAN: {
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      lua_pushinteger(L, sizeof(int));
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      break;
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    }
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    default: return 0;
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  }
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  return 1;
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}
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int luaopen_getsize(lua_State* L)
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{
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	lua_getglobal(L, "debug");
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	lua_pushcfunction(L, debug_getsize);
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	lua_setfield(L, -2, "getsize");
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	return 0;
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}