lib/liblua_wrapper.cc


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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/***************************************************************************
 *            liblua_wrapper.cc
 *
 *  Mon Aug 14 17:36:03 CEST 2006
 *  Copyright  2006 Bent Bisballe Nyeng
 *  deva@aasimon.org
 ****************************************************************************/

/*
 *  This file is part of MIaV.
 *
 *  MIaV is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  MIaV is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with MIaV; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
 */
#include "liblua_wrapper.h"

#include <stdexcept>

LibLUAWrapper::LibLUAWrapper()
{ 
  L = lua_open();
  //  luaL_openlibs(L);
}

LibLUAWrapper::~LibLUAWrapper()
{
  lua_close(L);
}

int LibLUAWrapper::loadFile(char *fname)
{
  int s;

  s = luaL_loadfile(L, fname);

  switch(s) {
  case 0: //no errors;
    break;
  case LUA_ERRSYNTAX: //syntax error during pre-compilation;
  case LUA_ERRMEM: //memory allocation error.
  case LUA_ERRFILE: //cannot open/read the file.
    strerr = std::string(lua_tostring(L, lua_gettop(L)));
    return 1;
  default:
    strerr = std::string("Unknown return value of luaL_loadfile.");
    return 1;
  }

  s = lua_pcall(L, 0, LUA_MULTRET, 0);

  switch(s) {
  case 0: // Success
    break;
  case LUA_ERRRUN:// a runtime error.
  case LUA_ERRMEM:// memory allocation error. For such errors, Lua does not call the error handler function.
  case LUA_ERRERR:// error while running the error handler function.
    strerr = std::string(lua_tostring(L, lua_gettop(L)));
    return 1;
  default:
    strerr = std::string("Unknown return value of lua_pcall.");
    return 1;
  }

  return 0;
}

int LibLUAWrapper::loadBuffer(char *buffer)
{
  int s;

  s = luaL_loadstring(L, buffer);

  switch(s) {
  case 0: //no errors;
    break;
  case LUA_ERRSYNTAX: //syntax error during pre-compilation;
  case LUA_ERRMEM: //memory allocation error.
    strerr = std::string(lua_tostring(L, lua_gettop(L)));
    return 1;
  default:
    strerr = std::string("Unknown return value of luaL_loadstring.");
    return 1;
  }

  s = lua_pcall(L, 0, LUA_MULTRET, 0);

  switch(s) {
  case 0: // Success
    break;
  case LUA_ERRRUN:// a runtime error.
  case LUA_ERRMEM:// memory allocation error. For such errors, Lua does not call the error handler function.
  case LUA_ERRERR:// error while running the error handler function.
    strerr = std::string(lua_tostring(L, lua_gettop(L)));
    return 1;
  default:
    strerr = std::string("Unknown return value of lua_pcall.");
    return 1;
  }

  return 0;
}

int LibLUAWrapper::getInteger(char *name)
{
  lua_getfield(L, LUA_GLOBALSINDEX, name); 
  
  int top = lua_gettop(L);

  int val = lua_tointeger(L, top);

  lua_remove(L, top);

  return val;
}

double LibLUAWrapper::getReal(char *name)
{
  lua_getfield(L, LUA_GLOBALSINDEX, name); 
  
  int top = lua_gettop(L);

  double val = lua_tonumber(L, top);

  lua_remove(L, top);

  return val;
}

bool LibLUAWrapper::getBoolean(char *name)
{
  lua_getfield(L, LUA_GLOBALSINDEX, name); 
  
  int top = lua_gettop(L);

  bool val = lua_toboolean(L, top);

  lua_remove(L, top);

  return val;
}

std::string LibLUAWrapper::getString(char *name)
{
  lua_getfield(L, LUA_GLOBALSINDEX, name); 
  
  int top = lua_gettop(L);

  std::string val = std::string(lua_tostring(L, top));

  lua_remove(L, top);

  return val;
}

std::string LibLUAWrapper::error()
{
  return strerr;
}

#ifdef LUA_TEST
// Compile with:
// g++ liblua_wrapper.cc -DLUA_TEST -I /home/deva/lib/lua-5.1.1/include/ -L /home/deva/lib/lua-5.1.1/lib -llua

const char preload[] =
"a = 42.0\n"
"b = 42\n"
"c = 42\n"
"d = \"42\"\n";

int main()
{
  LibLUAWrapper lua;

  if(lua.loadBuffer((char*)preload)) {
    fprintf(stderr, "LUA buffer error: %s\n", lua.error().c_str());
    return 1;
  }

  if(lua.loadFile("test.lua")) {
    fprintf(stderr, "LUA load error: %s\n", lua.error().c_str());
    return 1;
  }

  printf("a: %f\n", lua.getReal("a"));
  printf("b: %d\n", lua.getInteger("b"));
  printf("c: %d\n", lua.getBoolean("c"));
  printf("d: %s\n", lua.getString("d").c_str());

  return 0;
}

#endif