Update lua plugin to 5.2.3

Prior to this patch the Lua plugin used version 5.1.4. This change
reduces the number of modifications in the Lua source using some new
defines and because the upstream source is now more flexible.

Unless otherwise stated, l*.[ch] files are taken unmodified from the
upstream lua-5.2.3.

fscanf.c:
file descriptors in rockbox are just ints, they are hidden behind a
void* now so liolib requires less modifications. fscanf is updated to
use void* too.

getc.c: this is a new file required for getc implementation in lauxlib.c

lauxlib.c: LoadF replaced FILE* with int, the rockbox file
descriptor int are cast to FILE* (actually void* due to typedef).
getc uses the PREFIX version. stdin is not used, as per 5.1.4.

lbaselib.c: now uses strspn in the number parsing. print uses DEBUGF now
rather than being commented out.

lbitlib.c: use the built-in version from 5.2.3 rather than Reuben
Thomas's external library. Backwards compatible and adds some new bit
operations.

ldo.c: the LUAI_THROW/TRY defines are now in the core lua code, so have
been removed from rockconf.h

liolib.c: here the implementation has changed to use the LStream from
the original source, and cast the FILE* pointers to int. This has
reduced the number of modifications from the upstream version.

llex.c: the only change from upstream is to remove the locale include.

lmathlib.c: updated from the 5.2.3 version and re-applied the changes
that were made vs 5.1.4 for random numbers and to remove unsupported
float functions.

loadlib.c: upstream version, with the 5.1.4 changes for missing
functions.

lobject.c: upstream version, with ctype.h added and sprintf changed to
snprintf.

loslib.c: upstream version with locale.h removed and 5.1.4 changes for
unsupportable functions.

lstrlib.c: sprintf changed to snprintf.

ltable.c: upstream with the hashnum function from 5.1.4 to avoid frexp
in luai_hashnum.

luaconf.h: updated to 5.2.3 version, restored relevant parts from the
original 5.1.4 configuration. The COMPAT defines that are no longer
available are not included.

lundump.c: VERSION macro conflicts with the core Rockbox equivalent.

rocklib.c: luaL_reg is no longer available, replaced by luaL_Reg
equivalent. Moved checkboolean/optboolean functions to this file and out
of core lua files. luaL_getn is no longer available, replaced by
luaL_rawlen. luaL_register is deprecated, use the newlib/setfuncs
replacements. rli_init has to be called before setting up the newlib to
avoid overwriting the rb table.

rocklib_aux.pl: use rli_checkboolean from rocklib.c.

rocklua.c: new default bits library used, update the library loading
code with idiomatic 5.2 code.

strcspn.c: no longer needed, but strspn.c is required for strspn in
lbaselib.c

Change-Id: I0c7945c755f79083afe98ec117e1e8cf13de2651
Reviewed-on: http://gerrit.rockbox.org/774
Tested: Richard Quirk <richard.quirk@gmail.com>
Reviewed-by: Marcin Bukat <marcin.bukat@gmail.com>

1 files changed, 647 insertions, 327 deletions

diff --git a/apps/plugins/lua/lauxlib.c b/apps/plugins/lua/lauxlib.c
index b8020b7475..f451fb7c9e 100644
--- a/apps/plugins/lua/lauxlib.c
+++ b/apps/plugins/lua/lauxlib.c
@@ -1,11 +1,10 @@
 /*
-** $Id: lauxlib.c,v 1.159.1.3 2008/01/21 13:20:51 roberto Exp $
+** $Id: lauxlib.c,v 1.248.1.1 2013/04/12 18:48:47 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>
@@ -23,14 +22,127 @@
 #include "lua.h"
 
 #include "lauxlib.h"
+#include "rocklibc.h"
 
 
-#define FREELIST_REF	0	/* free list of references */
+/*
+** {======================================================
+** Traceback
+** =======================================================
+*/
+
+
+#define LEVELS1	12	/* size of the first part of the stack */
+#define LEVELS2	10	/* size of the second part of the stack */
+
+
+
+/*
+** search for 'objidx' in table at index -1.
+** return 1 + string at top if find a good name.
+*/
+static int findfield (lua_State *L, int objidx, int level) {
+  if (level == 0 || !lua_istable(L, -1))
+    return 0;  /* not found */
+  lua_pushnil(L);  /* start 'next' loop */
+  while (lua_next(L, -2)) {  /* for each pair in table */
+    if (lua_type(L, -2) == LUA_TSTRING) {  /* ignore non-string keys */
+      if (lua_rawequal(L, objidx, -1)) {  /* found object? */
+        lua_pop(L, 1);  /* remove value (but keep name) */
+        return 1;
+      }
+      else if (findfield(L, objidx, level - 1)) {  /* try recursively */
+        lua_remove(L, -2);  /* remove table (but keep name) */
+        lua_pushliteral(L, ".");
+        lua_insert(L, -2);  /* place '.' between the two names */
+        lua_concat(L, 3);
+        return 1;
+      }
+    }
+    lua_pop(L, 1);  /* remove value */
+  }
+  return 0;  /* not found */
+}
+
+
+static int pushglobalfuncname (lua_State *L, lua_Debug *ar) {
+  int top = lua_gettop(L);
+  lua_getinfo(L, "f", ar);  /* push function */
+  lua_pushglobaltable(L);
+  if (findfield(L, top + 1, 2)) {
+    lua_copy(L, -1, top + 1);  /* move name to proper place */
+    lua_pop(L, 2);  /* remove pushed values */
+    return 1;
+  }
+  else {
+    lua_settop(L, top);  /* remove function and global table */
+    return 0;
+  }
+}
+
+
+static void pushfuncname (lua_State *L, lua_Debug *ar) {
+  if (*ar->namewhat != '\0')  /* is there a name? */
+    lua_pushfstring(L, "function " LUA_QS, ar->name);
+  else if (*ar->what == 'm')  /* main? */
+      lua_pushliteral(L, "main chunk");
+  else if (*ar->what == 'C') {
+    if (pushglobalfuncname(L, ar)) {
+      lua_pushfstring(L, "function " LUA_QS, lua_tostring(L, -1));
+      lua_remove(L, -2);  /* remove name */
+    }
+    else
+      lua_pushliteral(L, "?");
+  }
+  else
+    lua_pushfstring(L, "function <%s:%d>", ar->short_src, ar->linedefined);
+}
 
 
-/* convert a stack index to positive */
-#define abs_index(L, i)		((i) > 0 || (i) <= LUA_REGISTRYINDEX ? (i) : \
-					lua_gettop(L) + (i) + 1)
+static int countlevels (lua_State *L) {
+  lua_Debug ar;
+  int li = 1, le = 1;
+  /* find an upper bound */
+  while (lua_getstack(L, le, &ar)) { li = le; le *= 2; }
+  /* do a binary search */
+  while (li < le) {
+    int m = (li + le)/2;
+    if (lua_getstack(L, m, &ar)) li = m + 1;
+    else le = m;
+  }
+  return le - 1;
+}
+
+
+LUALIB_API void luaL_traceback (lua_State *L, lua_State *L1,
+                                const char *msg, int level) {
+  lua_Debug ar;
+  int top = lua_gettop(L);
+  int numlevels = countlevels(L1);
+  int mark = (numlevels > LEVELS1 + LEVELS2) ? LEVELS1 : 0;
+  if (msg) lua_pushfstring(L, "%s\n", msg);
+  lua_pushliteral(L, "stack traceback:");
+  while (lua_getstack(L1, level++, &ar)) {
+    if (level == mark) {  /* too many levels? */
+      lua_pushliteral(L, "\n\t...");  /* add a '...' */
+      level = numlevels - LEVELS2;  /* and skip to last ones */
+    }
+    else {
+      lua_getinfo(L1, "Slnt", &ar);
+      lua_pushfstring(L, "\n\t%s:", ar.short_src);
+      if (ar.currentline > 0)
+        lua_pushfstring(L, "%d:", ar.currentline);
+      lua_pushliteral(L, " in ");
+      pushfuncname(L, &ar);
+      if (ar.istailcall)
+        lua_pushliteral(L, "\n\t(...tail calls...)");
+      lua_concat(L, lua_gettop(L) - top);
+    }
+  }
+  lua_concat(L, lua_gettop(L) - top);
+}
+
+/* }====================================================== */
 
 
 /*
@@ -39,7 +151,6 @@
 ** =======================================================
 */
 
-
 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? */
@@ -52,13 +163,13 @@ LUALIB_API int luaL_argerror (lua_State *L, int narg, const char *extramsg) {
                            ar.name, extramsg);
   }
   if (ar.name == NULL)
-    ar.name = "?";
+    ar.name = (pushglobalfuncname(L, &ar)) ? lua_tostring(L, -1) : "?";
   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) {
+static int typeerror (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);
@@ -66,7 +177,7 @@ LUALIB_API int luaL_typerror (lua_State *L, int narg, const char *tname) {
 
 
 static void tag_error (lua_State *L, int narg, int tag) {
-  luaL_typerror(L, narg, lua_typename(L, tag));
+  typeerror(L, narg, lua_typename(L, tag));
 }
 
 
@@ -93,24 +204,74 @@ LUALIB_API int luaL_error (lua_State *L, const char *fmt, ...) {
   return lua_error(L);
 }
 
-/* }====================================================== */
 
+LUALIB_API int luaL_fileresult (lua_State *L, int stat, const char *fname) {
+  int en = errno;  /* calls to Lua API may change this value */
+  if (stat) {
+    lua_pushboolean(L, 1);
+    return 1;
+  }
+  else {
+    lua_pushnil(L);
+    if (fname)
+      lua_pushfstring(L, "%s: %s", fname, strerror(en));
+    else
+      lua_pushstring(L, strerror(en));
+    lua_pushinteger(L, en);
+    return 3;
+  }
+}
 
-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));
+
+#if !defined(inspectstat)	/* { */
+
+#if defined(LUA_USE_POSIX)
+
+#include <sys/wait.h>
+
+/*
+** use appropriate macros to interpret 'pclose' return status
+*/
+#define inspectstat(stat,what)  \
+   if (WIFEXITED(stat)) { stat = WEXITSTATUS(stat); } \
+   else if (WIFSIGNALED(stat)) { stat = WTERMSIG(stat); what = "signal"; }
+
+#else
+
+#define inspectstat(stat,what)  /* no op */
+
+#endif
+
+#endif				/* } */
+
+
+LUALIB_API int luaL_execresult (lua_State *L, int stat) {
+  const char *what = "exit";  /* type of termination */
+  if (stat == -1)  /* error? */
+    return luaL_fileresult(L, 0, NULL);
+  else {
+    inspectstat(stat, what);  /* interpret result */
+    if (*what == 'e' && stat == 0)  /* successful termination? */
+      lua_pushboolean(L, 1);
+    else
+      lua_pushnil(L);
+    lua_pushstring(L, what);
+    lua_pushinteger(L, stat);
+    return 3;  /* return true/nil,what,code */
+  }
 }
 
+/* }====================================================== */
+
+
+/*
+** {======================================================
+** Userdata's metatable manipulation
+** =======================================================
+*/
 
 LUALIB_API int luaL_newmetatable (lua_State *L, const char *tname) {
-  lua_getfield(L, LUA_REGISTRYINDEX, tname);  /* get registry.name */
+  luaL_getmetatable(L, tname);  /* try to get metatable */
   if (!lua_isnil(L, -1))  /* name already in use? */
     return 0;  /* leave previous value on top, but return 0 */
   lua_pop(L, 1);
@@ -121,25 +282,64 @@ LUALIB_API int luaL_newmetatable (lua_State *L, const char *tname) {
 }
 
 
-LUALIB_API void *luaL_checkudata (lua_State *L, int ud, const char *tname) {
+LUALIB_API void luaL_setmetatable (lua_State *L, const char *tname) {
+  luaL_getmetatable(L, tname);
+  lua_setmetatable(L, -2);
+}
+
+
+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)) {  /* does it have the correct mt? */
-        lua_pop(L, 2);  /* remove both metatables */
-        return p;
-      }
+      luaL_getmetatable(L, 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;
     }
   }
-  luaL_typerror(L, ud, tname);  /* else error */
-  return NULL;  /* to avoid warnings */
+  return NULL;  /* value is not a userdata with a metatable */
 }
 
 
-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_checkudata (lua_State *L, int ud, const char *tname) {
+  void *p = luaL_testudata(L, ud, tname);
+  if (p == NULL) typeerror(L, ud, tname);
+  return p;
+}
+
+/* }====================================================== */
+
+
+/*
+** {======================================================
+** Argument check functions
+** =======================================================
+*/
+
+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 void luaL_checkstack (lua_State *L, int space, const char *msg) {
+  /* keep some extra space to run error routines, if needed */
+  const int extra = LUA_MINSTACK;
+  if (!lua_checkstack(L, space + extra)) {
+    if (msg)
+      luaL_error(L, "stack overflow (%s)", msg);
+    else
+      luaL_error(L, "stack overflow");
+  }
 }
 
 
@@ -174,8 +374,9 @@ LUALIB_API const char *luaL_optlstring (lua_State *L, int narg,
 
 
 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 */
+  int isnum;
+  lua_Number d = lua_tonumberx(L, narg, &isnum);
+  if (!isnum)
     tag_error(L, narg, LUA_TNUMBER);
   return d;
 }
@@ -187,268 +388,79 @@ LUALIB_API lua_Number luaL_optnumber (lua_State *L, int narg, lua_Number 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 */
+  int isnum;
+  lua_Integer d = lua_tointegerx(L, narg, &isnum);
+  if (!isnum)
     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_checkboolean (lua_State *L, int narg) {
-  int b = lua_toboolean(L, narg);
-  if( b == 0 && !lua_isboolean(L, narg))
-    tag_error(L, narg, LUA_TBOOLEAN);
-  return b;
-}
-
-
-LUALIB_API int luaL_optboolean (lua_State *L, int narg, int def) {
-  return luaL_opt(L, luaL_checkboolean, 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 lua_Unsigned luaL_checkunsigned (lua_State *L, int narg) {
+  int isnum;
+  lua_Unsigned d = lua_tounsignedx(L, narg, &isnum);
+  if (!isnum)
+    tag_error(L, narg, LUA_TNUMBER);
+  return d;
 }
 
 
-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 lua_Integer luaL_optinteger (lua_State *L, int narg,
+                                                      lua_Integer def) {
+  return luaL_opt(L, luaL_checkinteger, narg, def);
 }
 
 
-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);
+LUALIB_API lua_Unsigned luaL_optunsigned (lua_State *L, int narg,
+                                                        lua_Unsigned def) {
+  return luaL_opt(L, luaL_checkunsigned, narg, def);
 }
 
-#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;
-  }
-}
+/*
+** check whether buffer is using a userdata on the stack as a temporary
+** buffer
+*/
+#define buffonstack(B)	((B)->b != (B)->initb)
 
 
-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;
+/*
+** returns a pointer to a free area with at least 'sz' bytes
+*/
+LUALIB_API char *luaL_prepbuffsize (luaL_Buffer *B, size_t sz) {
+  lua_State *L = B->L;
+  if (B->size - B->n < sz) {  /* not enough space? */
+    char *newbuff;
+    size_t newsize = B->size * 2;  /* double buffer size */
+    if (newsize - B->n < sz)  /* not big enough? */
+      newsize = B->n + sz;
+    if (newsize < B->n || newsize - B->n < sz)
+      luaL_error(L, "buffer too large");
+    /* create larger buffer */
+    newbuff = (char *)lua_newuserdata(L, newsize * sizeof(char));
+    /* move content to new buffer */
+    memcpy(newbuff, B->b, B->n * sizeof(char));
+    if (buffonstack(B))
+      lua_remove(L, -2);  /* remove old buffer */
+    B->b = newbuff;
+    B->size = newsize;
   }
-}
-
-
-LUALIB_API char *luaL_prepbuffer (luaL_Buffer *B) {
-  if (emptybuffer(B))
-    adjuststack(B);
-  return B->buffer;
+  return &B->b[B->n];
 }
 
 
 LUALIB_API void luaL_addlstring (luaL_Buffer *B, const char *s, size_t l) {
-  while (l--)
-    luaL_addchar(B, *s++);
+  char *b = luaL_prepbuffsize(B, l);
+  memcpy(b, s, l * sizeof(char));
+  luaL_addsize(B, l);
 }
 
 
@@ -458,57 +470,72 @@ LUALIB_API void luaL_addstring (luaL_Buffer *B, const char *s) {
 
 
 LUALIB_API void luaL_pushresult (luaL_Buffer *B) {
-  emptybuffer(B);
-  lua_concat(B->L, B->lvl);
-  B->lvl = 1;
+  lua_State *L = B->L;
+  lua_pushlstring(L, B->b, B->n);
+  if (buffonstack(B))
+    lua_remove(L, -2);  /* remove old buffer */
+}
+
+
+LUALIB_API void luaL_pushresultsize (luaL_Buffer *B, size_t sz) {
+  luaL_addsize(B, sz);
+  luaL_pushresult(B);
 }
 
 
 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);
-  }
+  size_t l;
+  const char *s = lua_tolstring(L, -1, &l);
+  if (buffonstack(B))
+    lua_insert(L, -2);  /* put value below buffer */
+  luaL_addlstring(B, s, l);
+  lua_remove(L, (buffonstack(B)) ? -2 : -1);  /* remove value */
 }
 
 
 LUALIB_API void luaL_buffinit (lua_State *L, luaL_Buffer *B) {
   B->L = L;
-  B->p = B->buffer;
-  B->lvl = 0;
+  B->b = B->initb;
+  B->n = 0;
+  B->size = LUAL_BUFFERSIZE;
+}
+
+
+LUALIB_API char *luaL_buffinitsize (lua_State *L, luaL_Buffer *B, size_t sz) {
+  luaL_buffinit(L, B);
+  return luaL_prepbuffsize(B, sz);
 }
 
 /* }====================================================== */
 
 
+/*
+** {======================================================
+** Reference system
+** =======================================================
+*/
+
+/* index of free-list header */
+#define freelist	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] */
+  t = lua_absindex(L, t);
+  lua_rawgeti(L, t, freelist);  /* get first free element */
+  ref = (int)lua_tointeger(L, -1);  /* ref = t[freelist] */
   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, freelist);  /* (t[freelist] = t[ref]) */
   }
+  else  /* no free elements */
+    ref = (int)lua_rawlen(L, t) + 1;  /* get a new reference */
   lua_rawseti(L, t, ref);
   return ref;
 }
@@ -516,14 +543,15 @@ LUALIB_API int luaL_ref (lua_State *L, int t) {
 
 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] */
+    t = lua_absindex(L, t);
+    lua_rawgeti(L, t, freelist);
+    lua_rawseti(L, t, ref);  /* t[ref] = t[freelist] */
     lua_pushinteger(L, ref);
-    lua_rawseti(L, t, FREELIST_REF);  /* t[FREELIST_REF] = ref */
+    lua_rawseti(L, t, freelist);  /* t[freelist] = ref */
   }
 }
 
+/* }====================================================== */
 
 
 /*
@@ -533,22 +561,28 @@ LUALIB_API void luaL_unref (lua_State *L, int t, int ref) {
 */
 
 typedef struct LoadF {
-  int extraline;
+  int n;  /* number of pre-read characters */
   int f;
-  char buff[LUAL_BUFFERSIZE];
+  char buff[LUAL_BUFFERSIZE];  /* area for reading file */
 } LoadF;
 
-static const char *getF(lua_State *L, void *ud, size_t *size) {
+
+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";
+  (void)L;  /* not used */
+  if (lf->n > 0) {  /* are there pre-read characters to be read? */
+    *size = lf->n;  /* return them (chars already in buffer) */
+    lf->n = 0;  /* no more pre-read characters */
+  }
+  else {  /* read a block from file */
+    /* 'fread' can return > 0 *and* set the EOF flag. If next call to
+       'getF' called 'fread', it might still wait for user input.
+       The next check avoids this problem. */
+    *size = rb->read(lf->f, lf->buff, LUAL_BUFFERSIZE);
+    if (*size <= 0) return NULL;
+    return (*size > 0) ? lf->buff : NULL;
   }
-  *size = rb->read(lf->f, lf->buff, LUAL_BUFFERSIZE);
-  if (*size <= 0) return NULL;
-  return (*size > 0) ? lf->buff : NULL;
+  return lf->buff;
 }
 
 
@@ -560,16 +594,68 @@ static int errfile (lua_State *L, const char *what, int fnameindex) {
   return LUA_ERRFILE;
 }
 
-LUALIB_API int luaL_loadfile (lua_State *L, const char *filename) {
+
+static int skipBOM (LoadF *lf) {
+  const char *p = "\xEF\xBB\xBF";  /* Utf8 BOM mark */
+  int c;
+  lf->n = 0;
+  do {
+    c = PREFIX(getc)(lf->f);
+    if (c == EOF || c != *(const unsigned char *)p++) return c;
+    lf->buff[lf->n++] = c;  /* to be read by the parser */
+  } while (*p != '\0');
+  lf->n = 0;  /* prefix matched; discard it */
+  return PREFIX(getc)(lf->f);  /* return next character */
+}
+
+
+/*
+** reads the first character of file 'f' and skips an optional BOM mark
+** in its beginning plus its first line if it starts with '#'. Returns
+** true if it skipped the first line.  In any case, '*cp' has the
+** first "valid" character of the file (after the optional BOM and
+** a first-line comment).
+*/
+static int skipcomment (LoadF *lf, int *cp) {
+  int c = *cp = skipBOM(lf);
+  if (c == '#') {  /* first line is a comment (Unix exec. file)? */
+    do {  /* skip first line */
+      c = PREFIX(getc)(lf->f);
+    } while (c != EOF && c != '\n') ;
+    *cp = PREFIX(getc)(lf->f);  /* skip end-of-line, if present */
+    return 1;  /* there was a comment */
+  }
+  else return 0;  /* no comment */
+}
+
+
+LUALIB_API int luaL_loadfilex (lua_State *L, const char *filename,
+                                             const char *mode) {
   LoadF lf;
-  int status;
+  int status, readstatus;
+  int c;
   int fnameindex = lua_gettop(L) + 1;  /* index of filename on the stack */
-  lf.extraline = 0;
-  lf.f = rb->open(filename, O_RDONLY);
   lua_pushfstring(L, "@%s", filename);
+  lf.n = 0;
+  lf.f = rb->open(filename, O_RDONLY);
   if (lf.f < 0) return errfile(L, "open", fnameindex);
-  status = lua_load(L, getF, &lf, lua_tostring(L, -1));
-  rb->close(lf.f);
+  if (skipcomment(&lf, &c))  /* read initial portion */
+    lf.buff[lf.n++] = '\n';  /* add line to correct line numbers */
+  if (c == LUA_SIGNATURE[0] && filename) {  /* binary file? */
+    rb->close(lf.f);
+    lf.f = rb->open(filename, O_RDONLY);
+    if (lf.f < 0) return errfile(L, "reopen", fnameindex);
+    skipcomment(&lf, &c);  /* re-read initial portion */
+  }
+  if (c != EOF)
+    lf.buff[lf.n++] = c;  /* 'c' is the first character of the stream */
+  status = lua_load(L, getF, &lf, lua_tostring(L, -1), mode);
+  readstatus = 0;/*ferror(lf.f);*/
+  if (filename) rb->close(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;
 }
@@ -583,7 +669,7 @@ typedef struct LoadS {
 
 static const char *getS (lua_State *L, void *ud, size_t *size) {
   LoadS *ls = (LoadS *)ud;
-  (void)L;
+  (void)L;  /* not used */
   if (ls->size == 0) return NULL;
   *size = ls->size;
   ls->size = 0;
@@ -591,27 +677,245 @@ static const char *getS (lua_State *L, void *ud, size_t *size) {
 }
 
 
-LUALIB_API int luaL_loadbuffer (lua_State *L, const char *buff, size_t size,
-                                const char *name) {
+LUALIB_API int luaL_loadbufferx (lua_State *L, const char *buff, size_t size,
+                                 const char *name, const char *mode) {
   LoadS ls;
   ls.s = buff;
   ls.size = size;
-  return lua_load(L, getS, &ls, name);
+  return lua_load(L, getS, &ls, name, mode);
 }
 
 
-LUALIB_API int (luaL_loadstring) (lua_State *L, const char *s) {
+LUALIB_API int luaL_loadstring (lua_State *L, const char *s) {
   return luaL_loadbuffer(L, s, strlen(s), s);
 }
 
+/* }====================================================== */
+
+
+
+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 = lua_absindex(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 int luaL_len (lua_State *L, int idx) {
+  int l;
+  int isnum;
+  lua_len(L, idx);
+  l = (int)lua_tointegerx(L, -1, &isnum);
+  if (!isnum)
+    luaL_error(L, "object length is not a number");
+  lua_pop(L, 1);  /* remove object */
+  return l;
+}
+
+
+LUALIB_API const char *luaL_tolstring (lua_State *L, int idx, size_t *len) {
+  if (!luaL_callmeta(L, idx, "__tostring")) {  /* no metafield? */
+    switch (lua_type(L, idx)) {
+      case LUA_TNUMBER:
+      case LUA_TSTRING:
+        lua_pushvalue(L, idx);
+        break;
+      case LUA_TBOOLEAN:
+        lua_pushstring(L, (lua_toboolean(L, idx) ? "true" : "false"));
+        break;
+      case LUA_TNIL:
+        lua_pushliteral(L, "nil");
+        break;
+      default:
+        lua_pushfstring(L, "%s: %p", luaL_typename(L, idx),
+                                            lua_topointer(L, idx));
+        break;
+    }
+  }
+  return lua_tolstring(L, -1, len);
+}
+
+
+/*
+** {======================================================
+** Compatibility with 5.1 module functions
+** =======================================================
+*/
+#if defined(LUA_COMPAT_MODULE)
+
+static const char *luaL_findtable (lua_State *L, int idx,
+                                   const char *fname, int szhint) {
+  const char *e;
+  if (idx) 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;
+}
+
+
+/*
+** Count number of elements in a luaL_Reg list.
+*/
+static int libsize (const luaL_Reg *l) {
+  int size = 0;
+  for (; l && l->name; l++) size++;
+  return size;
+}
+
+
+/*
+** Find or create a module table with a given name. The function
+** first looks at the _LOADED table and, if that fails, try a
+** global variable with that name. In any case, leaves on the stack
+** the module table.
+*/
+LUALIB_API void luaL_pushmodule (lua_State *L, const char *modname,
+                                 int sizehint) {
+  luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 1);  /* get _LOADED table */
+  lua_getfield(L, -1, modname);  /* get _LOADED[modname] */
+  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) */
+    lua_pushglobaltable(L);
+    if (luaL_findtable(L, 0, modname, sizehint) != NULL)
+      luaL_error(L, "name conflict for module " LUA_QS, modname);
+    lua_pushvalue(L, -1);
+    lua_setfield(L, -3, modname);  /* _LOADED[modname] = new table */
+  }
+  lua_remove(L, -2);  /* remove _LOADED table */
+}
 
 
+LUALIB_API void luaL_openlib (lua_State *L, const char *libname,
+                               const luaL_Reg *l, int nup) {
+  luaL_checkversion(L);
+  if (libname) {
+    luaL_pushmodule(L, libname, libsize(l));  /* get/create library table */
+    lua_insert(L, -(nup + 1));  /* move library table to below upvalues */
+  }
+  if (l)
+    luaL_setfuncs(L, l, nup);
+  else
+    lua_pop(L, nup);  /* remove upvalues */
+}
+
+#endif
 /* }====================================================== */
 
+/*
+** set functions from list 'l' into table at top - 'nup'; each
+** function gets the 'nup' elements at the top as upvalues.
+** Returns with only the table at the stack.
+*/
+LUALIB_API void luaL_setfuncs (lua_State *L, const luaL_Reg *l, int nup) {
+  luaL_checkversion(L);
+  luaL_checkstack(L, nup, "too many upvalues");
+  for (; l->name != NULL; l++) {  /* fill the table with given functions */
+    int i;
+    for (i = 0; i < nup; i++)  /* copy upvalues to the top */
+      lua_pushvalue(L, -nup);
+    lua_pushcclosure(L, l->func, nup);  /* closure with those upvalues */
+    lua_setfield(L, -(nup + 2), l->name);
+  }
+  lua_pop(L, nup);  /* remove upvalues */
+}
+
+
+/*
+** ensure that stack[idx][fname] has a table and push that table
+** into the stack
+*/
+LUALIB_API int luaL_getsubtable (lua_State *L, int idx, const char *fname) {
+  lua_getfield(L, idx, fname);
+  if (lua_istable(L, -1)) return 1;  /* table already there */
+  else {
+    lua_pop(L, 1);  /* remove previous result */
+    idx = lua_absindex(L, idx);
+    lua_newtable(L);
+    lua_pushvalue(L, -1);  /* copy to be left at top */
+    lua_setfield(L, idx, fname);  /* assign new table to field */
+    return 0;  /* false, because did not find table there */
+  }
+}
+
+
+/*
+** stripped-down 'require'. Calls 'openf' to open a module,
+** registers the result in 'package.loaded' table and, if 'glb'
+** is true, also registers the result in the global table.
+** Leaves resulting module on the top.
+*/
+LUALIB_API void luaL_requiref (lua_State *L, const char *modname,
+                               lua_CFunction openf, int glb) {
+  lua_pushcfunction(L, openf);
+  lua_pushstring(L, modname);  /* argument to open function */
+  lua_call(L, 1, 1);  /* open module */
+  luaL_getsubtable(L, LUA_REGISTRYINDEX, "_LOADED");
+  lua_pushvalue(L, -2);  /* make copy of module (call result) */
+  lua_setfield(L, -2, modname);  /* _LOADED[modname] = module */
+  lua_pop(L, 1);  /* remove _LOADED table */
+  if (glb) {
+    lua_pushvalue(L, -1);  /* copy of 'mod' */
+    lua_setglobal(L, modname);  /* _G[modname] = module */
+  }
+}
+
+
+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);
+}
+
 
 static void *l_alloc (void *ud, void *ptr, size_t osize, size_t nsize) {
-  (void)ud;
-  (void)osize;
+  (void)ud; (void)osize;  /* not used */
   if (nsize == 0) {
     free(ptr);
     return NULL;
@@ -622,12 +926,11 @@ static void *l_alloc (void *ud, void *ptr, size_t osize, size_t nsize) {
 
 
 static int panic (lua_State *L) {
-    DEBUGF("PANIC: unprotected error in call to Lua API (%s)\n",
-        lua_tostring(L, -1));
-    rb->splashf(5 * HZ, "PANIC: unprotected error in call to Lua API (%s)",
+  DEBUGF("PANIC: unprotected error in call to Lua API (%s)\n",
+                   lua_tostring(L, -1));
+  rb->splashf(5 * HZ, "PANIC: unprotected error in call to Lua API (%s)",
         lua_tostring(L, -1));
-
-    return 0;
+  return 0;  /* return to Lua to abort */
 }
 
 
@@ -637,3 +940,20 @@ LUALIB_API lua_State *luaL_newstate (void) {
   return L;
 }
 
+
+LUALIB_API void luaL_checkversion_ (lua_State *L, lua_Number ver) {
+  const lua_Number *v = lua_version(L);
+  if (v != lua_version(NULL))
+    luaL_error(L, "multiple Lua VMs detected");
+  else if (*v != ver)
+    luaL_error(L, "version mismatch: app. needs %f, Lua core provides %f",
+                  ver, *v);
+  /* check conversions number -> integer types */
+  lua_pushnumber(L, -(lua_Number)0x1234);
+  if (lua_tointeger(L, -1) != -0x1234 ||
+      lua_tounsigned(L, -1) != (lua_Unsigned)-0x1234)
+    luaL_error(L, "bad conversion number->int;"
+                  " must recompile Lua with proper settings");
+  lua_pop(L, 1);
+}
+