/*
** $Id: lauxlib.c,v 1.5 1997/12/09 13:35:19 roberto Exp roberto $
** Auxiliar functions for building Lua libraries
** See Copyright Notice in lua.h
*/


#include <stdarg.h>
#include <stdio.h>
#include <string.h>

#include "lauxlib.h"
#include "lmem.h"
#include "lstate.h"
#include "lua.h"
#include "luadebug.h"



void luaL_arg_check (int cond, int numarg, char *extramsg)
{
  if (!cond) {
    char *funcname;
    lua_getobjname(lua_stackedfunction(0), &funcname);
    if (funcname == NULL)
      funcname = "???";
    if (extramsg == NULL)
      luaL_verror("bad argument #%d to function `%.50s'", numarg, funcname);
    else
      luaL_verror("bad argument #%d to function `%.50s' (%.100s)",
                      numarg, funcname, extramsg);
  }
}

char *luaL_check_string (int numArg)
{
  lua_Object o = lua_getparam(numArg);
  luaL_arg_check(lua_isstring(o), numArg, "string expected");
  return lua_getstring(o);
}

char *luaL_opt_string (int numArg, char *def)
{
  return (lua_getparam(numArg) == LUA_NOOBJECT) ? def :
                              luaL_check_string(numArg);
}

double luaL_check_number (int numArg)
{
  lua_Object o = lua_getparam(numArg);
  luaL_arg_check(lua_isnumber(o), numArg, "number expected");
  return lua_getnumber(o);
}


double luaL_opt_number (int numArg, double def)
{
  return (lua_getparam(numArg) == LUA_NOOBJECT) ? def :
                              luaL_check_number(numArg);
}  


lua_Object luaL_tablearg (int arg)
{
  lua_Object o = lua_getparam(arg);
  luaL_arg_check(lua_istable(o), arg, "table expected");
  return o;
}

lua_Object luaL_functionarg (int arg)
{
  lua_Object o = lua_getparam(arg);
  luaL_arg_check(lua_isfunction(o), arg, "function expected");
  return o;
}

lua_Object luaL_nonnullarg (int numArg)
{
  lua_Object o = lua_getparam(numArg);
  luaL_arg_check(o != LUA_NOOBJECT, numArg, "value expected");
  return o;
}

void luaL_openlib (struct luaL_reg *l, int n)
{
  int i;
  lua_open();  /* make sure lua is already open */
  for (i=0; i<n; i++)
    lua_register(l[i].name, l[i].func);
}


void luaL_verror (char *fmt, ...)
{
  char buff[500];
  va_list argp;
  va_start(argp, fmt);
  vsprintf(buff, fmt, argp);
  va_end(argp);
  lua_error(buff);
}


/*-------------------------------------------------------
**  Auxiliar buffer
-------------------------------------------------------*/

#define BUFF_STEP	32

#define openspace(size)  if (L->Mbuffnext+(size) > L->Mbuffsize) Openspace(size)

static void Openspace (int size)
{
  LState *l = L;  /* to optimize */
  int base = l->Mbuffbase-l->Mbuffer;
  l->Mbuffsize *= 2;
  if (l->Mbuffnext+size > l->Mbuffsize)  /* still not big enough? */
    l->Mbuffsize = l->Mbuffnext+size;
  l->Mbuffer = luaM_realloc(l->Mbuffer, l->Mbuffsize);
  l->Mbuffbase = l->Mbuffer+base;
}


char *luaL_openspace (int size)
{
  openspace(size);
  return L->Mbuffer+L->Mbuffnext;
}


void luaL_addchar (int c)
{
  openspace(BUFF_STEP);
  L->Mbuffer[L->Mbuffnext++] = c;
}


void luaL_resetbuffer (void)
{
  L->Mbuffnext = L->Mbuffbase-L->Mbuffer;
}


void luaL_addsize (int n)
{
  L->Mbuffnext += n;
}


int luaL_newbuffer (int size)
{
  int old = L->Mbuffbase-L->Mbuffer;
  openspace(size);
  L->Mbuffbase = L->Mbuffer+L->Mbuffnext;
  return old;
}


void luaL_oldbuffer (int old)
{
  L->Mbuffnext = L->Mbuffbase-L->Mbuffer;
  L->Mbuffbase = L->Mbuffer+old;
}


char *luaL_buffer (void)
{
  return L->Mbuffbase;
}