/*
** $Id: lauxlib.c,v 1.159.1.3 2008/01/21 13:20:51 roberto Exp $
** Auxiliary functions for building Lua libraries
** See Copyright Notice in lua.h
*/


#include "lua.h"
#include <ctype.h>
#if defined(LUA_CROSS_COMPILER) && defined(_MSC_VER)
#undef errno  	//msvc #defines errno, which interferes with our #include macro
#else
#include <errno.h>
#endif
#ifndef LUA_CROSS_COMPILER
#include "vfs.h"
#include "user_interface.h"
#endif
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>

/* This file uses only the official API of Lua.
** Any function declared here could be written as an application function.
*/

#define lauxlib_c
#include "lauxlib.h"
#define LUA_LIB

#include "lgc.h"
#include "ldo.h"
#include "lobject.h"
#include "lstate.h"

#define FREELIST_REF	0	/* free list of references */


/* convert a stack index to positive */
#define abs_index(L, i)	((i) > 0 || (i) <= LUA_REGISTRYINDEX ? (i) : \
			lua_gettop(L) + (i) + 1)

// Parameters for luaI_openlib
#define LUA_USECCLOSURES          0
#define LUA_USELIGHTFUNCTIONS     1

//#define DEBUG_ALLOCATOR
#ifdef DEBUG_ALLOCATOR
#ifdef LUA_CROSS_COMPILER
static void break_hook(void) {}
#define ASSERT(s) if (!(s)) {break_hook();}
#else
#define ASSERT(s) if (!(s)) {asm ("break 0,0" ::);}
#endif

/*
** {======================================================================
** Diagnosticd version for realloc. This is enabled only if the
** DEBUG_ALLOCATOR is defined.  It is a cutdown version of the allocator
** used in the Lua Test Suite -- a compromise between the ability catch
** most alloc/free errors and overruns and working within the RAM limits
** of the ESP8266 architecture.  ONLY FOR HEAVY HACKERS
** =======================================================================
*/
#define this_realloc debug_realloc
#define MARK  0x55  /* 01010101 (a nice pattern) */
#define MARKSIZE 2*sizeof(size_t)  /* size of marks after each block */
#define fillmem(mem,size) memset(mem, ~MARK, size)

typedef union MemHeader MemHeader;
union MemHeader {
  L_Umaxalign a;  /* ensures maximum alignment for Header */
  struct {
    size_t size;
    MemHeader *next;
    size_t mark[2];
  };
};

typedef struct Memcontrol {  /* memory-allocator control variables */
  MemHeader *start;
  lu_int32 numblocks;
  lu_int32 total;
  lu_int32 maxmem;
  lu_int32 memlimit;
} Memcontrol;
static Memcontrol mc = {NULL,0,0,0,32768*64};
static size_t marker[2] = {0,0};

static void scanBlocks (void) {
  MemHeader *p = mc.start;
  int i;
  char s,e;
  for (i=0; p ;i++) {
    s = memcmp(p->mark, marker, MARKSIZE) ? '<' : ' ';
    e = memcmp(cast(char *, p+1) + p->size, marker, MARKSIZE) ? '>' : ' ';
    printf("%4u %p %8lu %c %c\n", i, p, p->size, s, e);
    ASSERT(p->next);
    p = p->next;
  }
}

static int checkBlocks (void) {
  MemHeader *p = mc.start;
  while(p) {
    if (memcmp(p->mark, marker, MARKSIZE)  ||
       memcmp(cast(char *, p+1) + p->size, marker, MARKSIZE)) {
      scanBlocks();
      return 0;
    }
    p = p->next;
  }
  return 1;
}


static void freeblock (MemHeader *block) {
  if (block) {
    MemHeader *p = mc.start;
    MemHeader *next = block->next;
    size_t size = block->size;
    ASSERT(checkBlocks());
    if (p == block) {
      mc.start = next;
    } else {
      while (p->next != block) {
        ASSERT(p);
        p = p->next;
      }
      p->next = next;
    }
    fillmem(block, sizeof(MemHeader) + size + MARKSIZE);  /* erase block */
    free(block);  /* actually free block */
    mc.numblocks--;  /* update counts */
    mc.total -= size;
  }
}

void *debug_realloc (void *b, size_t oldsize, size_t size) {
  MemHeader *block = cast(MemHeader *, b);
  ASSERT(checkBlocks());
  if (!marker[0]) memset(marker, MARK, MARKSIZE);
  if (block == NULL) {
    oldsize = 0;
  } else {
    block--;  /* go to real header */
    ASSERT(!memcmp(block->mark, marker, MARKSIZE))
    ASSERT(oldsize == block->size);
    ASSERT(!memcmp(cast(char *, b)+oldsize, marker, MARKSIZE));
  }
  if (size == 0) {
    freeblock(block);
    return NULL;
  } else if (size > oldsize && mc.total+size-oldsize > mc.memlimit)
    return NULL;  /* fake a memory allocation error */
  else {
    MemHeader *newblock;
    size_t commonsize = (oldsize < size) ? oldsize : size;
    size_t realsize = sizeof(MemHeader) + size + MARKSIZE;
    newblock = cast(MemHeader *, malloc(realsize));  /* alloc a new block */
    if (newblock == NULL)
      return NULL;  /* really out of memory? */
    if (block) {
      memcpy(newblock + 1, block + 1, commonsize);  /* copy old contents */
      freeblock(block);  /* erase (and check) old copy */
    }
    /* initialize new part of the block with something weird */
    if (size > commonsize)
      fillmem(cast(char *, newblock + 1) + commonsize, size - commonsize);
    /* initialize marks after block */
    memset(newblock->mark, MARK, MARKSIZE);
    newblock->size = size;
    newblock->next = mc.start;
    mc.start = newblock;
    memset(cast(char *, newblock + 1)+ size, MARK, MARKSIZE);
    mc.total += size;
    if (mc.total > mc.maxmem)
      mc.maxmem = mc.total;
    mc.numblocks++;
    return (newblock + 1);
  }
}


/* }====================================================================== */
#else
#define this_realloc(p,os,s) realloc(p,s)
#endif /* DEBUG_ALLOCATOR */

/*
** {======================================================
** Error-report functions
** =======================================================
*/


LUALIB_API int luaL_argerror (lua_State *L, int narg, const char *extramsg) {
  lua_Debug ar;
  if (!lua_getstack(L, 0, &ar))  /* no stack frame? */
    return luaL_error(L, "bad argument #%d (%s)", narg, extramsg);
  lua_getinfo(L, "n", &ar);
  if (strcmp(ar.namewhat, "method") == 0) {
    narg--;  /* do not count `self' */
    if (narg == 0)  /* error is in the self argument itself? */
      return luaL_error(L, "calling " LUA_QS " on bad self (%s)",
                           ar.name, extramsg);
  }
  if (ar.name == NULL)
    ar.name = "?";
  return luaL_error(L, "bad argument #%d to " LUA_QS " (%s)",
                        narg, ar.name, extramsg);
}


LUALIB_API int luaL_typerror (lua_State *L, int narg, const char *tname) {
  const char *msg = lua_pushfstring(L, "%s expected, got %s",
                                    tname, luaL_typename(L, narg));
  return luaL_argerror(L, narg, msg);
}


static void tag_error (lua_State *L, int narg, int tag) {
  luaL_typerror(L, narg, lua_typename(L, tag));
}


LUALIB_API void luaL_where (lua_State *L, int level) {
  lua_Debug ar;
  if (lua_getstack(L, level, &ar)) {  /* check function at level */
    lua_getinfo(L, "Sl", &ar);  /* get info about it */
    if (ar.currentline > 0) {  /* is there info? */
      lua_pushfstring(L, "%s:%d: ", ar.short_src, ar.currentline);
      return;
    }
  }
  lua_pushliteral(L, "");  /* else, no information available... */
}


LUALIB_API int luaL_error (lua_State *L, const char *fmt, ...) {
  va_list argp;
  va_start(argp, fmt);
  luaL_where(L, 1);
  lua_pushvfstring(L, fmt, argp);
  va_end(argp);
  lua_concat(L, 2);
  return lua_error(L);
}

/* }====================================================== */


LUALIB_API int luaL_checkoption (lua_State *L, int narg, const char *def,
                                 const char *const lst[]) {
  const char *name = (def) ? luaL_optstring(L, narg, def) :
                             luaL_checkstring(L, narg);
  int i;
  for (i=0; lst[i]; i++)
    if (strcmp(lst[i], name) == 0)
      return i;
  return luaL_argerror(L, narg,
                       lua_pushfstring(L, "invalid option " LUA_QS, name));
}


LUALIB_API int luaL_newmetatable (lua_State *L, const char *tname) {
  lua_getfield(L, LUA_REGISTRYINDEX, tname);  /* get registry.name */
  if (!lua_isnil(L, -1))  /* name already in use? */
    return 0;  /* leave previous value on top, but return 0 */
  lua_pop(L, 1);
  lua_newtable(L);  /* create metatable */
  lua_pushvalue(L, -1);
  lua_setfield(L, LUA_REGISTRYINDEX, tname);  /* registry.name = metatable */
  return 1;
}

LUALIB_API int luaL_rometatable (lua_State *L, const char* tname, const ROTable *p) {
  lua_getfield(L, LUA_REGISTRYINDEX, tname);  /* get registry.name */
  if (!lua_isnil(L, -1))  /* name already in use? */
    return 0;  /* leave previous value on top, but return 0 */
  lua_pop(L, 1);
  lua_pushrotable(L, p);
  lua_pushvalue(L, -1);
  lua_setfield(L, LUA_REGISTRYINDEX, tname);  /* registry.name = metatable */
  return 1;
}

LUALIB_API void *luaL_testudata (lua_State *L, int ud, const char *tname) {
  void *p = lua_touserdata(L, ud);
  if (p != NULL) {  /* value is a userdata? */
    if (lua_getmetatable(L, ud)) {  /* does it have a metatable? */
      lua_getfield(L, LUA_REGISTRYINDEX, tname);  /* get correct metatable */
      if (!lua_rawequal(L, -1, -2))  /* not the same? */
        p = NULL;  /* value is a userdata with wrong metatable */
      lua_pop(L, 2);  /* remove both metatables */
      return p;
    }
  }
  return NULL;  /* value is not a userdata with a metatable */
}

LUALIB_API void *luaL_checkudata (lua_State *L, int ud, const char *tname) {
  void *p = luaL_testudata(L, ud, tname);
  if (p == NULL) luaL_typerror(L, ud, tname);
  return p;
}

LUALIB_API void luaL_checkstack (lua_State *L, int space, const char *mes) {
  if (!lua_checkstack(L, space))
    luaL_error(L, "stack overflow (%s)", mes);
}


LUALIB_API void luaL_checktype (lua_State *L, int narg, int t) {
  if (lua_type(L, narg) != t)
    tag_error(L, narg, t);
}


LUALIB_API void luaL_checkany (lua_State *L, int narg) {
  if (lua_type(L, narg) == LUA_TNONE)
    luaL_argerror(L, narg, "value expected");
}


LUALIB_API const char *luaL_checklstring (lua_State *L, int narg, size_t *len) {
  const char *s = lua_tolstring(L, narg, len);
  if (!s) tag_error(L, narg, LUA_TSTRING);
  return s;
}


LUALIB_API const char *luaL_optlstring (lua_State *L, int narg,
                                        const char *def, size_t *len) {
  if (lua_isnoneornil(L, narg)) {
    if (len)
      *len = (def ? strlen(def) : 0);
    return def;
  }
  else return luaL_checklstring(L, narg, len);
}


LUALIB_API lua_Number luaL_checknumber (lua_State *L, int narg) {
  lua_Number d = lua_tonumber(L, narg);
  if (d == 0 && !lua_isnumber(L, narg))  /* avoid extra test when d is not 0 */
    tag_error(L, narg, LUA_TNUMBER);
  return d;
}


LUALIB_API lua_Number luaL_optnumber (lua_State *L, int narg, lua_Number def) {
  return luaL_opt(L, luaL_checknumber, narg, def);
}


LUALIB_API lua_Integer luaL_checkinteger (lua_State *L, int narg) {
  lua_Integer d = lua_tointeger(L, narg);
  if (d == 0 && !lua_isnumber(L, narg))  /* avoid extra test when d is not 0 */
    tag_error(L, narg, LUA_TNUMBER);
  return d;
}


LUALIB_API lua_Integer luaL_optinteger (lua_State *L, int narg,
                                                      lua_Integer def) {
  return luaL_opt(L, luaL_checkinteger, narg, def);
}


LUALIB_API int luaL_getmetafield (lua_State *L, int obj, const char *event) {
  if (!lua_getmetatable(L, obj))  /* no metatable? */
    return 0;
  lua_pushstring(L, event);
  lua_rawget(L, -2);
  if (lua_isnil(L, -1)) {
    lua_pop(L, 2);  /* remove metatable and metafield */
    return 0;
  }
  else {
    lua_remove(L, -2);  /* remove only metatable */
    return 1;
  }
}


LUALIB_API int luaL_callmeta (lua_State *L, int obj, const char *event) {
  obj = abs_index(L, obj);
  if (!luaL_getmetafield(L, obj, event))  /* no metafield? */
    return 0;
  lua_pushvalue(L, obj);
  lua_call(L, 1, 1);
  return 1;
}


LUALIB_API void (luaL_register) (lua_State *L, const char *libname,
                                const luaL_Reg *l) {
  luaI_openlib(L, libname, l, 0, LUA_USECCLOSURES);
}

LUALIB_API void (luaL_register_light) (lua_State *L, const char *libname,
                                const luaL_Reg *l) {
  luaI_openlib(L, libname, l, 0, LUA_USELIGHTFUNCTIONS);
}

static int libsize (const luaL_Reg *l) {
  int size = 0;
  for (; l->name; l++) size++;
  return size;
}


LUALIB_API void luaI_openlib (lua_State *L, const char *libname,
                              const luaL_Reg *l, int nup, int ftype) {
  if (libname) {
    int size = libsize(l);
    /* check whether lib already exists */
    luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 1);
    lua_getfield(L, -1, libname);  /* get _LOADED[libname] */
    if (!lua_istable(L, -1)) {  /* not found? */
      lua_pop(L, 1);  /* remove previous result */
      /* try global variable (and create one if it does not exist) */
      if (luaL_findtable(L, LUA_GLOBALSINDEX, libname, size) != NULL)
        luaL_error(L, "name conflict for module " LUA_QS, libname);
      lua_pushvalue(L, -1);
      lua_setfield(L, -3, libname);  /* _LOADED[libname] = new table */
    }
    lua_remove(L, -2);  /* remove _LOADED table */
    lua_insert(L, -(nup+1));  /* move library table to below upvalues */
  }
  for (; l->name; l++) {
    int i;
    for (i=0; i<nup; i++)  /* copy upvalues to the top */
      lua_pushvalue(L, -nup);
    if (ftype == LUA_USELIGHTFUNCTIONS)
      lua_pushcfunction(L, l->func);
    else
      lua_pushcclosure(L, l->func, nup);
    lua_setfield(L, -(nup+2), l->name);
  }
  lua_pop(L, nup);  /* remove upvalues */
}



/*
** {======================================================
** getn-setn: size for arrays
** =======================================================
*/

#if defined(LUA_COMPAT_GETN)

static int checkint (lua_State *L, int topop) {
  int n = (lua_type(L, -1) == LUA_TNUMBER) ? lua_tointeger(L, -1) : -1;
  lua_pop(L, topop);
  return n;
}


static void getsizes (lua_State *L) {
  lua_getfield(L, LUA_REGISTRYINDEX, "LUA_SIZES");
  if (lua_isnil(L, -1)) {  /* no `size' table? */
    lua_pop(L, 1);  /* remove nil */
    lua_newtable(L);  /* create it */
    lua_pushvalue(L, -1);  /* `size' will be its own metatable */
    lua_setmetatable(L, -2);
    lua_pushliteral(L, "kv");
    lua_setfield(L, -2, "__mode");  /* metatable(N).__mode = "kv" */
    lua_pushvalue(L, -1);
    lua_setfield(L, LUA_REGISTRYINDEX, "LUA_SIZES");  /* store in register */
  }
}


LUALIB_API void luaL_setn (lua_State *L, int t, int n) {
  t = abs_index(L, t);
  lua_pushliteral(L, "n");
  lua_rawget(L, t);
  if (checkint(L, 1) >= 0) {  /* is there a numeric field `n'? */
    lua_pushliteral(L, "n");  /* use it */
    lua_pushinteger(L, n);
    lua_rawset(L, t);
  }
  else {  /* use `sizes' */
    getsizes(L);
    lua_pushvalue(L, t);
    lua_pushinteger(L, n);
    lua_rawset(L, -3);  /* sizes[t] = n */
    lua_pop(L, 1);  /* remove `sizes' */
  }
}


LUALIB_API int luaL_getn (lua_State *L, int t) {
  int n;
  t = abs_index(L, t);
  lua_pushliteral(L, "n");  /* try t.n */
  lua_rawget(L, t);
  if ((n = checkint(L, 1)) >= 0) return n;
  getsizes(L);  /* else try sizes[t] */
  lua_pushvalue(L, t);
  lua_rawget(L, -2);
  if ((n = checkint(L, 2)) >= 0) return n;
  return (int)lua_objlen(L, t);
}

#endif

/* }====================================================== */



LUALIB_API const char *luaL_gsub (lua_State *L, const char *s, const char *p,
                                                               const char *r) {
  const char *wild;
  size_t l = strlen(p);
  luaL_Buffer b;
  luaL_buffinit(L, &b);
  while ((wild = strstr(s, p)) != NULL) {
    luaL_addlstring(&b, s, wild - s);  /* push prefix */
    luaL_addstring(&b, r);  /* push replacement in place of pattern */
    s = wild + l;  /* continue after `p' */
  }
  luaL_addstring(&b, s);  /* push last suffix */
  luaL_pushresult(&b);
  return lua_tostring(L, -1);
}


LUALIB_API const char *luaL_findtable (lua_State *L, int idx,
                                       const char *fname, int szhint) {
  const char *e;
  lua_pushvalue(L, idx);
  do {
    e = strchr(fname, '.');
    if (e == NULL) e = fname + strlen(fname);
    lua_pushlstring(L, fname, e - fname);
    lua_rawget(L, -2);

    if (lua_isnil(L, -1)) {  /* no such field? */
      lua_pop(L, 1);  /* remove this nil */
      lua_createtable(L, 0, (*e == '.' ? 1 : szhint)); /* new table for field */
      lua_pushlstring(L, fname, e - fname);
      lua_pushvalue(L, -2);
      lua_settable(L, -4);  /* set new table into field */
    }
    else if (!lua_istable(L, -1)) {  /* field has a non-table value? */
      lua_pop(L, 2);  /* remove table and value */
      return fname;  /* return problematic part of the name */
    }
    lua_remove(L, -2);  /* remove previous table */
    fname = e + 1;
  } while (*e == '.');
  return NULL;
}



/*
** {======================================================
** Generic Buffer manipulation
** =======================================================
*/


#define bufflen(B)	((B)->p - (B)->buffer)
#define bufffree(B)	((size_t)(LUAL_BUFFERSIZE - bufflen(B)))

#define LIMIT	(LUA_MINSTACK/2)


static int emptybuffer (luaL_Buffer *B) {
  size_t l = bufflen(B);
  if (l == 0) return 0;  /* put nothing on stack */
  else {
    lua_pushlstring(B->L, B->buffer, l);
    B->p = B->buffer;
    B->lvl++;
    return 1;
  }
}


static void adjuststack (luaL_Buffer *B) {
  if (B->lvl > 1) {
    lua_State *L = B->L;
    int toget = 1;  /* number of levels to concat */
    size_t toplen = lua_strlen(L, -1);
    do {
      size_t l = lua_strlen(L, -(toget+1));
      if (B->lvl - toget + 1 >= LIMIT || toplen > l) {
        toplen += l;
        toget++;
      }
      else break;
    } while (toget < B->lvl);
    lua_concat(L, toget);
    B->lvl = B->lvl - toget + 1;
  }
}


LUALIB_API char *luaL_prepbuffer (luaL_Buffer *B) {
  if (emptybuffer(B))
    adjuststack(B);
  return B->buffer;
}


LUALIB_API void luaL_addlstring (luaL_Buffer *B, const char *s, size_t l) {
  while (l--)
    luaL_addchar(B, *s++);
}


LUALIB_API void luaL_addstring (luaL_Buffer *B, const char *s) {
  luaL_addlstring(B, s, strlen(s));
}


LUALIB_API void luaL_pushresult (luaL_Buffer *B) {
  emptybuffer(B);
  lua_concat(B->L, B->lvl);
  B->lvl = 1;
}


LUALIB_API void luaL_addvalue (luaL_Buffer *B) {
  lua_State *L = B->L;
  size_t vl;
  const char *s = lua_tolstring(L, -1, &vl);
  if (vl <= bufffree(B)) {  /* fit into buffer? */
    memcpy(B->p, s, vl);  /* put it there */
    B->p += vl;
    lua_pop(L, 1);  /* remove from stack */
  }
  else {
    if (emptybuffer(B))
      lua_insert(L, -2);  /* put buffer before new value */
    B->lvl++;  /* add new value into B stack */
    adjuststack(B);
  }
}


LUALIB_API void luaL_buffinit (lua_State *L, luaL_Buffer *B) {
  B->L = L;
  B->p = B->buffer;
  B->lvl = 0;
}

/* }====================================================== */


LUALIB_API int luaL_ref (lua_State *L, int t) {
  int ref;
  t = abs_index(L, t);
  if (lua_isnil(L, -1)) {
    lua_pop(L, 1);  /* remove from stack */
    return LUA_REFNIL;  /* `nil' has a unique fixed reference */
  }
  lua_rawgeti(L, t, FREELIST_REF);  /* get first free element */
  ref = (int)lua_tointeger(L, -1);  /* ref = t[FREELIST_REF] */
  lua_pop(L, 1);  /* remove it from stack */
  if (ref != 0) {  /* any free element? */
    lua_rawgeti(L, t, ref);  /* remove it from list */
    lua_rawseti(L, t, FREELIST_REF);  /* (t[FREELIST_REF] = t[ref]) */
  }
  else {  /* no free elements */
    ref = (int)lua_objlen(L, t);
    ref++;  /* create new reference */
  }
  lua_rawseti(L, t, ref);
  return ref;
}


LUALIB_API void luaL_unref (lua_State *L, int t, int ref) {
  if (ref >= 0) {
    t = abs_index(L, t);
    lua_rawgeti(L, t, FREELIST_REF);
    lua_rawseti(L, t, ref);  /* t[ref] = t[FREELIST_REF] */
    lua_pushinteger(L, ref);
    lua_rawseti(L, t, FREELIST_REF);  /* t[FREELIST_REF] = ref */
  }
}


LUALIB_API void (luaL_reref) (lua_State *L, int t, int *ref) {
  int reft;
/*
 * If the ref is positive and the entry in table t exists then
 * overwrite the value otherwise fall through to luaL_ref()
 */   
  if (ref) {
    if (*ref >= 0) {
      t = abs_index(L, t);
      lua_rawgeti(L, t, *ref);
      reft = lua_type(L, -1);
      lua_pop(L, 1);
      if (reft != LUA_TNIL) {
        lua_rawseti(L, t, *ref);
        return;
      }
    }
    *ref = luaL_ref(L, t);
  }
}

/*
** {======================================================
** Load functions
** =======================================================
*/

typedef struct LoadF {
  int extraline;
#ifdef LUA_CROSS_COMPILER
  FILE *f;
#else
  int f;
#endif
  char buff[LUAL_BUFFERSIZE];
} LoadF;

#ifdef LUA_CROSS_COMPILER
#  define freopen_bin(f,fn) freopen(f,"rb",fn)
#  define read_buff(b,f) fread(b, 1, sizeof (b), f)
#else
#  define strerror(n) ""
#undef feof
#  define feof(f)        vfs_eof(f)
#undef fopen
#  define fopen(f, m)    vfs_open(f, m)
#  define freopen_bin(fn,f) ((void) vfs_close(f), vfs_open(fn, "r"))
#undef getc
#  define getc(f)        vfs_getc(f)
#undef ungetc
#  define ungetc(c,f)    vfs_ungetc(c, f)
#  define read_buff(b,f) vfs_read(f, b, sizeof (b))
#endif

static const char *getF (lua_State *L, void *ud, size_t *size) {
  LoadF *lf = (LoadF *)ud;
  (void)L;
  if (lf->extraline) {
    lf->extraline = 0;
    *size = 1;
    return "\n";
  }
  if (feof(lf->f)) return NULL;
  *size = read_buff(lf->buff, lf->f);
  return (*size > 0) ? lf->buff : NULL;
}


static int errfile (lua_State *L, const char *what, int fnameindex) {
  const char *serr = strerror(errno);
  const char *filename = lua_tostring(L, fnameindex) + 1;
  lua_pushfstring(L, "cannot %s %s: %s", what, filename, serr);
  lua_remove(L, fnameindex);
  return LUA_ERRFILE;
}


LUALIB_API int luaL_loadfile (lua_State *L, const char *filename) {
  LoadF lf;
  int status, readstatus;
  int c;
  int fnameindex = lua_gettop(L) + 1;  /* index of filename on the stack */
  lf.extraline = 0;

  if (filename == NULL) {
#ifdef LUA_CROSS_COMPILER
    lua_pushliteral(L, "=stdin");
    lf.f = stdin;
#else
    return luaL_error(L, "filename is NULL");
#endif
  }
  else {
    lua_pushfstring(L, "@%s", filename);
    lf.f = fopen(filename, "r");
    if (!lf.f) return errfile(L, "open", fnameindex);
  }
  c = getc(lf.f);
  if (c == '#') {  /* Unix exec. file? */
    lf.extraline = 1;
    while ((c = getc(lf.f)) != EOF && c != '\n') ;  /* skip first line */
    if (c == '\n') c = getc(lf.f);
  }
  if (c == LUA_SIGNATURE[0] && filename) {  /* binary file? */
    lf.f = freopen_bin(filename, lf.f);  /* reopen in binary mode */
    if (!lf.f) return errfile(L, "reopen", fnameindex);
    /* skip eventual `#!...' */
   while ((c = getc(lf.f)) != EOF && c != LUA_SIGNATURE[0]) {}

   lf.extraline = 0;
  }
  ungetc(c, lf.f);
  status = lua_load(L, getF, &lf, lua_tostring(L, -1));
#ifdef LUA_CROSS_COMPILER
  readstatus = ferror(lf.f);
  if (filename) fclose(lf.f);  /* close file (even in case of errors) */
  if (readstatus) {
    lua_settop(L, fnameindex);  /* ignore results from `lua_load' */
    return errfile(L, "read", fnameindex);
  }
#else
  (void) readstatus;              /* avoid compile error */
  if (filename) vfs_close(lf.f);  /* close file (even in case of errors) */
#endif
  lua_remove(L, fnameindex);
  return status;
}


typedef struct LoadS {
  const char *s;
  size_t size;
} LoadS;


static const char *getS (lua_State *L, void *ud, size_t *size) {
  LoadS *ls = (LoadS *)ud;
  (void)L;
  if (L == NULL && size == NULL) // direct mode check
    return NULL;
  if (ls->size == 0) return NULL;
  *size = ls->size;
  ls->size = 0;
  return ls->s;
}


LUALIB_API int luaL_loadbuffer (lua_State *L, const char *buff, size_t size,
                                const char *name) {
  LoadS ls;
  ls.s = buff;
  ls.size = size;
  return lua_load(L, getS, &ls, name);
}


LUALIB_API int (luaL_loadstring) (lua_State *L, const char *s) {
  return luaL_loadbuffer(L, s, strlen(s), s);
}



/* }====================================================== */


static int l_check_memlimit(lua_State *L, size_t needbytes) {
  global_State *g = G(L);
  int cycle_count = 0;
  lu_mem limit = g->memlimit - needbytes;
  /* don't allow allocation if it requires more memory then the total limit. */
  if (needbytes > g->memlimit) return 1;
  /* make sure the GC is not disabled. */
  if (!is_block_gc(L)) {
    while (g->totalbytes >= limit) {
      /* only allow the GC to finished atleast 1 full cycle. */
      if (g->gcstate == GCSpause && ++cycle_count > 1) break;
      luaC_step(L);
    }
  }
  return (g->totalbytes >= limit) ? 1 : 0;
}


static void *l_alloc (void *ud, void *ptr, size_t osize, size_t nsize) {
  lua_State *L = (lua_State *)ud;
  int mode = L == NULL ? 0 : G(L)->egcmode;
  void *nptr;

  if (nsize == 0) {
#ifdef DEBUG_ALLOCATOR
    return (void *)this_realloc(ptr, osize, nsize);
#else
    free(ptr);
    return NULL;
#endif
  }
  if (L != NULL && (mode & EGC_ALWAYS)) /* always collect memory if requested */
    luaC_fullgc(L);
#ifndef LUA_CROSS_COMPILER
  if (L != NULL && (mode & EGC_ON_MEM_LIMIT) && G(L)->memlimit < 0 &&
      (system_get_free_heap_size() < (-G(L)->memlimit)))
    luaC_fullgc(L);
#endif
  if(nsize > osize && L != NULL) {
#if defined(LUA_STRESS_EMERGENCY_GC)
    luaC_fullgc(L);
#endif
    if(G(L)->memlimit > 0 && (mode & EGC_ON_MEM_LIMIT) && l_check_memlimit(L, nsize - osize))
      return NULL;
  }
  nptr = (void *)this_realloc(ptr, osize, nsize);
  if (nptr == NULL && L != NULL && (mode & EGC_ON_ALLOC_FAILURE)) {
    luaC_fullgc(L); /* emergency full collection. */
    nptr = (void *)this_realloc(ptr, osize, nsize); /* try allocation again */
  }
  return nptr;
}

LUALIB_API void luaL_assertfail(const char *file, int line, const char *message) {
  dbg_printf("ASSERT@%s(%d): %s\n", file, line, message);
#if defined(LUA_CROSS_COMPILER)
  exit(1);
#endif
}

#ifdef DEVELOPMENT_USE_GDB
/*
 *  This is a simple stub used by lua_assert() if DEVELOPMENT_USE_GDB is defined.
 *  Instead of crashing out with an assert error, this hook starts the GDB remote
 *  stub if not already running and then issues a break.  The rationale here is
 *  that when testing the developer might be using screen/PuTTY to work interactively
 *  with the Lua Interpreter via UART0.  However if an assert triggers, then there
 * is the option to exit the interactive session and start the Xtensa remote GDB
 * which will then sync up with the remote GDB client to allow forensics of the error.
 */
extern void gdbstub_init(void);
extern void gdbstub_redirect_output(int);

LUALIB_API void lua_debugbreak (void) {
#ifdef LUA_CROSS_COMPILER
  puts(" lua_debugbreak ");  /* allows gdb BT analysis of assert fails */
#else
  static int repeat_entry = 0;
  if  (repeat_entry == 0) {
    dbg_printf("Start up the gdb stub if not already started\n");
    gdbstub_init();
    gdbstub_redirect_output(1);
    repeat_entry = 1;
  }
  asm("break 0,0" ::);
#endif
}
#endif


static int panic (lua_State *L) {
  (void)L;  /* to avoid warnings */
  lua_writestringerror("PANIC: unprotected error in call to Lua API (%s)\n",
                   lua_tostring(L, -1));
  while (1) {}
  return 0;
}


LUALIB_API lua_State *luaL_newstate (void) {
  lua_State *L = lua_newstate(l_alloc, NULL);
  lua_setallocf(L, l_alloc, L); /* allocator need lua_State. */
  if (L) lua_atpanic(L, &panic);
  return L;
}