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/*

** $Id: lauxlib.c,v 1.159 2006/03/21 19:31:09 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", size);

    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, LUAL_BUFFERSIZE, 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] && lf.f != stdin) {  /* binary file? */

    fclose(lf.f);

    lf.f = fopen(filename, "rb");  /* 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 (lf.f != stdin) 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;

}