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path: root/src/lauxlib.c
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/*
** $Id: lstring.c,v 2.8.1.1 2007/12/27 13:02:25 roberto Exp $
** String table (keeps all strings handled by Lua)
** See Copyright Notice in lua.h
*/


#include <string.h>

#define lstring_c
#define LUA_CORE

#include "lua.h"

#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "lstring.h"



void luaS_resize (lua_State *L, int newsize) {
  GCObject **newhash;
  stringtable *tb;
  int i;
  if (G(L)->gcstate == GCSsweepstring)
    return;  /* cannot resize during GC traverse */
  newhash = luaM_newvector(L, newsize, GCObject *);
  tb = &G(L)->strt;
  for (i=0; i<newsize; i++) newhash[i] = NULL;
  /* rehash */
  for (i=0; i<tb->size; i++) {
    GCObject *p = tb->hash[i];
    while (p) {  /* for each node in the list */
      GCObject *next = p->gch.next;  /* save next */
      unsigned int h = gco2ts(p)->hash;
      int h1 = lmod(h, newsize);  /* new position */
      lua_assert(cast_int(h%newsize) == lmod(h, newsize));
      p->gch.next = newhash[h1];  /* chain it */
      newhash[h1] = p;
      p = next;
    }
  }
  luaM_freearray(L, tb->hash, tb->size, TString *);
  tb->size = newsize;
  tb->hash = newhash;
}


static TString *newlstr (lua_State *L, const char *str, size_t l,
                                       unsigned int h) {
  TString *ts;
  stringtable *tb;
  if (l+1 > (MAX_SIZET - sizeof(TString))/sizeof(char))
    luaM_toobig(L);
  ts = cast(TString *, luaM_malloc(L, (l+1)*sizeof(char)+sizeof(TString)));
  ts->tsv.len = l;
  ts->tsv.hash = h;
  ts->tsv.marked = luaC_white(G(L));
  ts->tsv.tt = LUA_TSTRING;
  ts->tsv.reserved = 0;
  memcpy(ts+1, str, l*sizeof(char));
  ((char *)(ts+1))[l] = '\0';  /* ending 0 */
  tb = &G(L)->strt;
  h = lmod(h, tb->size);
  ts->tsv.next = tb->hash[h];  /* chain new entry */
  tb->hashpre { line-height: 125%; }
td.linenos .normal { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
span.linenos { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
td.linenos .special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
span.linenos.special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
.highlight .hll { background-color: #ffffcc }
.highlight .c { color: #888888 } /* Comment */
.highlight .err { color: #a61717; background-color: #e3d2d2 } /* Error */
.highlight .k { color: #008800; font-weight: bold } /* Keyword */
.highlight .ch { color: #888888 } /* Comment.Hashbang */
.highlight .cm { color: #888888 } /* Comment.Multiline */
.highlight .cp { color: #cc0000; font-weight: bold } /* Comment.Preproc */
.highlight .cpf { color: #888888 } /* Comment.PreprocFile */
.highlight .c1 { color: #888888 } /* Comment.Single */
.highlight .cs { color: #cc0000; font-weight: bold; background-color: #fff0f0 } /* Comment.Special */
.highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .ges { font-weight: bold; font-style: italic } /* Generic.EmphStrong */
.highlight .gr { color: #aa0000 } /* Generic.Error */
.highlight .gh { color: #333333 } /* Generic.Heading */
.highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */
.highlight .go { color: #888888 } /* Generic.Output */
.highlight .gp { color: #555555 } /* Generic.Prompt */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #666666 } /* Generic.Subheading */
.highlight .gt { color: #aa0000 } /* Generic.Traceback */
.highlight .kc { color: #008800; font-weight: bold } /* Keyword.Constant */
.highlight .kd { color: #008800; font-weight: bold } /* Keyword.Declaration */
.highlight .kn { color: #008800; font-weight: bold } /* Keyword.Namespace */
.highlight .kp { color: #008800 } /* Keyword.Pseudo */
.highlight .kr { color: #008800; font-weight: bold } /* Keyword.Reserved */
.highlight .kt { color: #888888; font-weight: bold } /* Keyword.Type */
.highlight .m { color: #0000DD; font-weight: bold } /* Literal.Number */
.highlight .s { color: #dd2200; background-color: #fff0f0 } /* Literal.String */
.highlight .na { color: #336699 } /* Name.Attribute */
.highlight .nb { color: #003388 } /* Name.Builtin */
.highlight .nc { color: #bb0066; font-weight: bold } /* Name.Class */
.highlight .no { color: #003366; font-weight: bold } /* Name.Constant */
.highlight .nd { color: #555555 } /* Name.Decorator */
.highlight .ne { color: #bb0066; font-weight: bold } /* Name.Exception */
.highlight .nf { color: #0066bb; font-weight: bold } /* Name.Function */
.highlight .nl { color: #336699; font-style: italic } /* Name.Label */
.highlight .nn { color: #bb0066; font-weight: bold } /* Name.Namespace */
.highlight .py { color: #336699; font-weight: bold } /* Name.Property */
.highlight .nt { color: #bb0066; font-weight: bold } /* Name.Tag */
.highlight .nv { color: #336699 } /* Name.Variable */
.highlight .ow { color: #008800 } /* Operator.Word */
.highlight .w { color: #bbbbbb } /* Text.Whitespace */
.highlight .mb { color: #0000DD; font-weight: bold } /* Literal.Number.Bin */
.highlight .mf { color: #0000DD; font-weight: bold } /* Literal.Number.Float */
.highlight .mh { color: #0000DD; font-weight: bold } /* Literal.Number.Hex */
.highlight .mi { color: #0000DD; font-weight: bold } /* Literal.Number.Integer */
.highlight .mo { color: #0000DD; font-weight: bold } /* Literal.Number.Oct */
.highlight .sa { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Affix */
.highlight .sb { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Backtick */
.highlight .sc { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Char */
.highlight .dl { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Delimiter */
.highlight .sd { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Doc */
.highlight .s2 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Double */
.highlight .se { color: #0044dd; background-color: #fff0f0 } /* Literal.String.Escape */
.highlight .sh { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Heredoc */
.highlight .si { color: #3333bb; background-color: #fff0f0 } /* Literal.String.Interpol */
.highlight .sx { color: #22bb22; background-color: #f0fff0 } /* Literal.String.Other */
.highlight .sr { color: #008800; background-color: #fff0ff } /* Literal.String.Regex */
.highlight .s1 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Single */
.highlight .ss { color: #aa6600; background-color: #fff0f0 } /* Literal.String.Symbol */
.highlight .bp { color: #003388 } /* Name.Builtin.Pseudo */
.highlight .fm { color: #0066bb; font-weight: bold } /* Name.Function.Magic */
.highlight .vc { color: #336699 } /* Name.Variable.Class */
.highlight .vg { color: #dd7700 } /* Name.Variable.Global */
.highlight .vi { color: #3333bb } /* Name.Variable.Instance */
.highlight .vm { color: #336699 } /* Name.Variable.Magic */
.highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */
/*
** $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 <ctype.h>
#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>


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

#define lauxlib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.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)


/*
** {======================================================
** 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 void *luaL_checkudata (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)) {  /* does it have the correct mt? */
        lua_pop(L, 2);  /* remove both metatables */
        return p;
      }
    }
  }
  luaL_typerror(L, ud, tname);  /* else error */
  return NULL;  /* to avoid warnings */
}


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);
}


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) {
  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);
    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 */
  }
}



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

typedef struct LoadF {
  int extraline;
  FILE *f;
  char buff[LUAL_BUFFERSIZE];
} LoadF;


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 = fread(lf->buff, 1, sizeof(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) {
    lua_pushliteral(L, "=stdin");
    lf.f = stdin;
  }
  else {
    lua_pushfstring(L, "@%s", filename);
    lf.f = fopen(filename, "r");
    if (lf.f == NULL) 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(filename, "rb", lf.f);  /* reopen in binary mode */
    if (lf.f == NULL) 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));
  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);
  }
  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 (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 void *l_alloc (void *ud, void *ptr, size_t osize, size_t nsize) {
  (void)ud;
  (void)osize;
  if (nsize == 0) {
    free(ptr);
    return NULL;
  }
  else
    return realloc(ptr, nsize);
}


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


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