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, 380 insertions, 156 deletions

diff --git a/apps/plugins/lua/liolib.c b/apps/plugins/lua/liolib.c
index 7a43915f20..a282dd1ac0 100644
--- a/apps/plugins/lua/liolib.c
+++ b/apps/plugins/lua/liolib.c
@@ -1,10 +1,21 @@
 /*
-** $Id: liolib.c,v 2.73.1.3 2008/01/18 17:47:43 roberto Exp $
+** $Id: liolib.c,v 2.112.1.1 2013/04/12 18:48:47 roberto Exp $
 ** Standard I/O (and system) library
 ** See Copyright Notice in lua.h
 */
 
 
+/*
+** This definition must come before the inclusion of 'stdio.h'; it
+** should not affect non-POSIX systems
+*/
+#if !defined(_FILE_OFFSET_BITS)
+#define _LARGEFILE_SOURCE       1
+#define _FILE_OFFSET_BITS       64
+#endif
+
+
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -19,46 +30,111 @@
 #include "rocklibc.h"
 
 
+#if !defined(lua_checkmode)
 
-#define IO_INPUT    1
-#define IO_OUTPUT   2
+/*
+** Check whether 'mode' matches '[rwa]%+?b?'.
+** Change this macro to accept other modes for 'fopen' besides
+** the standard ones.
+*/
+#define lua_checkmode(mode) \
+        (*mode != '\0' && strchr("rwa", *(mode++)) != NULL &&   \
+        (*mode != '+' || ++mode) &&  /* skip if char is '+' */  \
+        (*mode != 'b' || ++mode) &&  /* skip if char is 'b' */  \
+        (*mode == '\0'))
 
+#endif
 
-static const char *const fnames[] = {"input", "output"};
+/*
+** {======================================================
+** lua_popen spawns a new process connected to the current
+** one through the file streams.
+** =======================================================
+*/
 
+#if !defined(lua_popen) /* { */
 
-static int pushresult (lua_State *L, int i, const char *filename) {
-  int en = errno;
-  if (i) {
-    lua_pushboolean(L, 1);
-    return 1;
-  }
-  else {
-    lua_pushnil(L);
-    if (filename)
-      lua_pushfstring(L, "%s: %s", filename, strerror(en));
-    else
-      lua_pushfstring(L, "%s", strerror(en));
-    lua_pushinteger(L, 0);
-    return 3;
-  }
-}
+#if defined(LUA_USE_POPEN)      /* { */
 
+#define lua_popen(L,c,m)        ((void)L, fflush(NULL), popen(c,m))
+#define lua_pclose(L,file)      ((void)L, pclose(file))
 
-static void fileerror (lua_State *L, int arg, const char *filename) {
-  lua_pushfstring(L, "%s: %s", filename, strerror(errno));
-  luaL_argerror(L, arg, lua_tostring(L, -1));
-}
+#elif defined(LUA_WIN)          /* }{ */
+
+#define lua_popen(L,c,m)                ((void)L, _popen(c,m))
+#define lua_pclose(L,file)              ((void)L, _pclose(file))
+
+
+#else                           /* }{ */
+
+#define lua_popen(L,c,m)                ((void)((void)c, m),  \
+                luaL_error(L, LUA_QL("popen") " not supported"), (FILE*)0)
+#define lua_pclose(L,file)              ((void)((void)L, file), -1)
+
+
+#endif                          /* } */
+
+#endif                  /* } */
+
+/* }====================================================== */
+
+
+/*
+** {======================================================
+** lua_fseek: configuration for longer offsets
+** =======================================================
+*/
+
+#if !defined(lua_fseek) && !defined(LUA_ANSI)   /* { */
+
+#if defined(LUA_USE_POSIX)      /* { */
+
+#define l_fseek(f,o,w)          fseeko(f,o,w)
+#define l_ftell(f)              ftello(f)
+#define l_seeknum               off_t
+
+#elif defined(LUA_WIN) && !defined(_CRTIMP_TYPEINFO) \
+   && defined(_MSC_VER) && (_MSC_VER >= 1400)   /* }{ */
+/* Windows (but not DDK) and Visual C++ 2005 or higher */
+
+#define l_fseek(f,o,w)          _fseeki64(f,o,w)
+#define l_ftell(f)              _ftelli64(f)
+#define l_seeknum               __int64
+
+#endif  /* } */
+
+#endif                  /* } */
+
+
+#if !defined(l_fseek)           /* default definitions */
+#define l_fseek(f,o,w)          fseek(f,o,w)
+#define l_ftell(f)              ftell(f)
+#define l_seeknum               long
+#endif
+
+/* }====================================================== */
+
+
+#define IO_PREFIX       "_IO_"
+#define IO_INPUT        (IO_PREFIX "input")
+#define IO_OUTPUT       (IO_PREFIX "output")
+
+
+typedef luaL_Stream LStream;
+
+
+#define tolstream(L)    ((LStream *)luaL_checkudata(L, 1, LUA_FILEHANDLE))
+
+#define isclosed(p)     ((p)->closef == NULL)
 
 
 static int io_type (lua_State *L) {
-  void *ud;
+  LStream *p;
   luaL_checkany(L, 1);
-  ud = lua_touserdata(L, 1);
-  lua_getfield(L, LUA_REGISTRYINDEX, LUA_FILEHANDLE);
-  if (ud == NULL || !lua_getmetatable(L, 1) || !lua_rawequal(L, -2, -1))
+  p = (LStream *)luaL_testudata(L, 1, LUA_FILEHANDLE);
+  if (p == NULL)
     lua_pushnil(L);  /* not a file */
-  else if (*((int *)ud) < 0)
+  else if (isclosed(p))
     lua_pushliteral(L, "closed file");
   else
     lua_pushliteral(L, "file");
@@ -66,76 +142,97 @@ static int io_type (lua_State *L) {
 }
 
 
-static int* tofile (lua_State *L) {
-  int *f = (int*) luaL_checkudata(L, 1, LUA_FILEHANDLE);
-  if (*f < 0)
-    luaL_error(L, "attempt to use a closed file");
-  return f;
+static int f_tostring (lua_State *L) {
+  LStream *p = tolstream(L);
+  if (isclosed(p))
+    lua_pushliteral(L, "file (closed)");
+  else
+    lua_pushfstring(L, "file (%p)", p->f);
+  return 1;
 }
 
 
+static FILE *tofile (lua_State *L) {
+  LStream *p = tolstream(L);
+  if (isclosed(p))
+    luaL_error(L, "attempt to use a closed file");
+  lua_assert(p->f);
+  return p->f;
+}
+
 
 /*
 ** When creating file handles, always creates a `closed' file handle
 ** before opening the actual file; so, if there is a memory error, the
 ** file is not left opened.
 */
-static int* newfile (lua_State *L) {
-  int *pf = (int *)lua_newuserdata(L, sizeof(int));
-  *pf = -1;  /* file handle is currently `closed' */
-  luaL_getmetatable(L, LUA_FILEHANDLE);
-  lua_setmetatable(L, -2);
-  return pf;
-}
-
-
-/*
-** function to close regular files
-*/
-static int io_fclose (lua_State *L) {
-  int *p = tofile(L);
-  int ok = (rb->close(*p) == 0);
-  *p = -1;
-  return pushresult(L, ok, NULL);
+static LStream *newprefile (lua_State *L) {
+  LStream *p = (LStream *)lua_newuserdata(L, sizeof(LStream));
+  p->closef = NULL;  /* mark file handle as 'closed' */
+  luaL_setmetatable(L, LUA_FILEHANDLE);
+  return p;
 }
 
 
-static inline int aux_close (lua_State *L) {
-  return io_fclose(L);
+static int aux_close (lua_State *L) {
+  LStream *p = tolstream(L);
+  lua_CFunction cf = p->closef;
+  p->closef = NULL;  /* mark stream as closed */
+  return (*cf)(L);  /* close it */
 }
 
 
 static int io_close (lua_State *L) {
-  if (lua_isnone(L, 1))
-    lua_rawgeti(L, LUA_ENVIRONINDEX, IO_OUTPUT);
-  tofile(L);  /* make sure argument is a file */
+  if (lua_isnone(L, 1))  /* no argument? */
+    lua_getfield(L, LUA_REGISTRYINDEX, IO_OUTPUT);  /* use standard output */
+  tofile(L);  /* make sure argument is an open stream */
   return aux_close(L);
 }
 
 
-static int io_gc (lua_State *L) {
-  int f = *(int*) luaL_checkudata(L, 1, LUA_FILEHANDLE);
-  /* ignore closed files */
-  if (f >= 0)
-    aux_close(L);
+static int f_gc (lua_State *L) {
+  LStream *p = tolstream(L);
+  if (!isclosed(p) && p->f != NULL)
+    aux_close(L);  /* ignore closed and incompletely open files */
   return 0;
 }
 
 
-static int io_tostring (lua_State *L) {
-  int f = *(int*) luaL_checkudata(L, 1, LUA_FILEHANDLE);
-  if (f < 0)
-    lua_pushliteral(L, "file (closed)");
-  else
-    lua_pushfstring(L, "file (%d)", f);
-  return 1;
+/*
+** function to close regular files
+*/
+static int io_fclose (lua_State *L) {
+  LStream *p = tolstream(L);
+  int res = rb->close((int)p->f);
+  return luaL_fileresult(L, (res == 0), NULL);
+}
+
+
+static LStream *newfile (lua_State *L) {
+  LStream *p = newprefile(L);
+  p->f = NULL;
+  p->closef = &io_fclose;
+  return p;
+}
+
+
+static void opencheck (lua_State *L, const char *fname, const char *mode) {
+  LStream *p = newfile(L);
+  int flags = O_RDONLY;
+  if (strcmp(mode, "w") == 0)
+    flags = O_WRONLY;
+  p->f = (FILE*)rb->open(fname, flags);
+  if (p->f == NULL)
+    luaL_error(L, "cannot open file " LUA_QS " (%s)", fname, strerror(errno));
 }
 
 
 static int io_open (lua_State *L) {
   const char *filename = luaL_checkstring(L, 1);
   const char *mode = luaL_optstring(L, 2, "r");
-  int *pf = newfile(L);
+  LStream *p = newfile(L);
+  const char *md = mode;  /* to traverse/check mode */
+  luaL_argcheck(L, lua_checkmode(md), 2, "invalid mode");
   int flags = 0;
   if(*(mode+1) == '+') {
     flags = O_RDWR;
@@ -158,84 +255,117 @@ static int io_open (lua_State *L) {
   }
   if((*mode == 'w' || *mode == 'a') && !rb->file_exists(filename))
     flags |= O_CREAT;
-  *pf = rb->open(filename, flags, 0666);
-  return (*pf < 0) ? pushresult(L, 0, filename) : 1;
+  int pf = rb->open(filename, flags, 0666);
+  p->f = (FILE*)pf;
+  return (pf < 0) ? luaL_fileresult(L, 0, filename) : 1;
 }
 
 
-static int* getiofile (lua_State *L, int findex) {
-  int *f;
-  lua_rawgeti(L, LUA_ENVIRONINDEX, findex);
-  f = (int *)lua_touserdata(L, -1);
-  if (f == NULL || *f < 0)
-    luaL_error(L, "standard %s file is closed", fnames[findex - 1]);
-  return f;
+#if 0
+/*
+** function to close 'popen' files
+*/
+static int io_pclose (lua_State *L) {
+  LStream *p = tolstream(L);
+  return luaL_execresult(L, lua_pclose(L, p->f));
 }
 
 
-static int g_iofile (lua_State *L, int f, int flags) {
+static int io_popen (lua_State *L) {
+  const char *filename = luaL_checkstring(L, 1);
+  const char *mode = luaL_optstring(L, 2, "r");
+  LStream *p = newprefile(L);
+  p->f = lua_popen(L, filename, mode);
+  p->closef = &io_pclose;
+  return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
+}
+
+
+static int io_tmpfile (lua_State *L) {
+  LStream *p = newfile(L);
+  p->f = tmpfile();
+  return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1;
+}
+#endif
+
+
+static FILE *getiofile (lua_State *L, const char *findex) {
+  LStream *p;
+  lua_getfield(L, LUA_REGISTRYINDEX, findex);
+  p = (LStream *)lua_touserdata(L, -1);
+  if (isclosed(p))
+    luaL_error(L, "standard %s file is closed", findex + strlen(IO_PREFIX));
+  return p->f;
+}
+
+
+static int g_iofile (lua_State *L, const char *f, const char *mode) {
   if (!lua_isnoneornil(L, 1)) {
     const char *filename = lua_tostring(L, 1);
-    if (filename) {
-      int *pf = newfile(L);
-      *pf = rb->open(filename, flags);
-      if (*pf < 0)
-        fileerror(L, 1, filename);
-    }
+    if (filename)
+      opencheck(L, filename, mode);
     else {
       tofile(L);  /* check that it's a valid file handle */
       lua_pushvalue(L, 1);
     }
-    lua_rawseti(L, LUA_ENVIRONINDEX, f);
+    lua_setfield(L, LUA_REGISTRYINDEX, f);
   }
   /* return current value */
-  lua_rawgeti(L, LUA_ENVIRONINDEX, f);
+  lua_getfield(L, LUA_REGISTRYINDEX, f);
   return 1;
 }
 
 
 static int io_input (lua_State *L) {
-  return g_iofile(L, IO_INPUT, O_RDONLY);
+  return g_iofile(L, IO_INPUT, "r");
 }
 
 
 static int io_output (lua_State *L) {
-  return g_iofile(L, IO_OUTPUT, O_WRONLY);
+  return g_iofile(L, IO_OUTPUT, "w");
 }
 
 
 static int io_readline (lua_State *L);
 
 
-static void aux_lines (lua_State *L, int idx, int toclose) {
-  lua_pushvalue(L, idx);
+static void aux_lines (lua_State *L, int toclose) {
+  int i;
+  int n = lua_gettop(L) - 1;  /* number of arguments to read */
+  /* ensure that arguments will fit here and into 'io_readline' stack */
+  luaL_argcheck(L, n <= LUA_MINSTACK - 3, LUA_MINSTACK - 3, "too many options");
+  lua_pushvalue(L, 1);  /* file handle */
+  lua_pushinteger(L, n);  /* number of arguments to read */
   lua_pushboolean(L, toclose);  /* close/not close file when finished */
-  lua_pushcclosure(L, io_readline, 2);
+  for (i = 1; i <= n; i++) lua_pushvalue(L, i + 1);  /* copy arguments */
+  lua_pushcclosure(L, io_readline, 3 + n);
 }
 
 
 static int f_lines (lua_State *L) {
   tofile(L);  /* check that it's a valid file handle */
-  aux_lines(L, 1, 0);
+  aux_lines(L, 0);
   return 1;
 }
 
 
 static int io_lines (lua_State *L) {
-  if (lua_isnoneornil(L, 1)) {  /* no arguments? */
-    /* will iterate over default input */
-    lua_rawgeti(L, LUA_ENVIRONINDEX, IO_INPUT);
-    return f_lines(L);
+  int toclose;
+  if (lua_isnone(L, 1)) lua_pushnil(L);  /* at least one argument */
+  if (lua_isnil(L, 1)) {  /* no file name? */
+    lua_getfield(L, LUA_REGISTRYINDEX, IO_INPUT);  /* get default input */
+    lua_replace(L, 1);  /* put it at index 1 */
+    tofile(L);  /* check that it's a valid file handle */
+    toclose = 0;  /* do not close it after iteration */
   }
-  else {
+  else {  /* open a new file */
     const char *filename = luaL_checkstring(L, 1);
-    int *pf = newfile(L);
-    *pf = rb->open(filename, O_RDONLY);
-    if (*pf < 0)
-      fileerror(L, 1, filename);
-    aux_lines(L, lua_gettop(L), 1);
-    return 1;
+    opencheck(L, filename, "r");
+    lua_replace(L, 1);  /* put file at index 1 */
+    toclose = 1;  /* close it after iteration */
   }
+  aux_lines(L, toclose);
+  return 1;
 }
 
 
@@ -245,72 +375,89 @@ static int io_lines (lua_State *L) {
 ** =======================================================
 */
 
-static int read_number (lua_State *L, int *f) {
+
+static int read_number (lua_State *L, FILE *f) {
   lua_Number d;
-  if (PREFIX(fscanf)(*f, LUA_NUMBER_SCAN, &d) == 1) {
+  if (PREFIX(fscanf)(f, LUA_NUMBER_SCAN, &d) == 1) {
     lua_pushnumber(L, d);
     return 1;
   }
-  else return 0;  /* read fails */
+  else {
+   lua_pushnil(L);  /* "result" to be removed */
+   return 0;  /* read fails */
+  }
 }
 
 
-static int test_eof (lua_State *L, int *f) {
-  ssize_t s = rb->lseek(*f, 0, SEEK_CUR);
+static int test_eof (lua_State *L, FILE *f) {
+  ssize_t s = rb->lseek((int)f, 0, SEEK_CUR);
   lua_pushlstring(L, NULL, 0);
-  return s != rb->filesize(*f);
+  return s != rb->filesize((int)f);
 }
 
 
 /* Rockbox already defines read_line() */
-static int _read_line (lua_State *L, int *f) {
+static int _read_line (lua_State *L, FILE *f, int chop) {
   luaL_Buffer b;
   luaL_buffinit(L, &b);
   for (;;) {
     size_t l;
     size_t r;
     char *p = luaL_prepbuffer(&b);
-    r = rb->read_line(*f, p, LUAL_BUFFERSIZE);
+    r = rb->read_line((int)f, p, LUAL_BUFFERSIZE);
     l = strlen(p);
     if (l == 0 || p[l-1] != '\n')
       luaL_addsize(&b, l);
     else {
-      luaL_addsize(&b, l - 1);  /* do not include `eol' */
+      luaL_addsize(&b, l - chop);  /* chop 'eol' if needed */
       luaL_pushresult(&b);  /* close buffer */
       return 1;  /* read at least an `eol' */
     }
     if (r < LUAL_BUFFERSIZE) {  /* eof? */
       luaL_pushresult(&b);  /* close buffer */
-      return (lua_objlen(L, -1) > 0);  /* check whether read something */
+      return (lua_rawlen(L, -1) > 0);  /* check whether read something */
     }
   }
 }
 
 
-static int read_chars (lua_State *L, int *f, size_t n) {
-  size_t rlen;  /* how much to read */
-  size_t nr;  /* number of chars actually read */
+#define MAX_SIZE_T      (~(size_t)0)
+
+static void read_all (lua_State *L, FILE *f) {
+  size_t rlen = LUAL_BUFFERSIZE;  /* how much to read in each cycle */
   luaL_Buffer b;
   luaL_buffinit(L, &b);
-  rlen = LUAL_BUFFERSIZE;  /* try to read that much each time */
-  do {
-    char *p = luaL_prepbuffer(&b);
-    if (rlen > n) rlen = n;  /* cannot read more than asked */
-    nr = rb->read(*f, p, rlen);
+  for (;;) {
+    char *p = luaL_prepbuffsize(&b, rlen);
+    size_t nr = rb->read((int)f, p, rlen);
     luaL_addsize(&b, nr);
-    n -= nr;  /* still have to read `n' chars */
-  } while (n > 0 && nr == rlen);  /* until end of count or eof */
+    if (nr < rlen) break;  /* eof? */
+    else if (rlen <= (MAX_SIZE_T / 4))  /* avoid buffers too large */
+      rlen *= 2;  /* double buffer size at each iteration */
+  }
+  luaL_pushresult(&b);  /* close buffer */
+}
+
+
+static int read_chars (lua_State *L, FILE *f, size_t n) {
+  size_t nr;  /* number of chars actually read */
+  char *p;
+  luaL_Buffer b;
+  luaL_buffinit(L, &b);
+  p = luaL_prepbuffsize(&b, n);  /* prepare buffer to read whole block */
+  nr = rb->read((int)f, p, n);  /* try to read 'n' chars */
+  luaL_addsize(&b, nr);
   luaL_pushresult(&b);  /* close buffer */
-  return (n == 0 || lua_objlen(L, -1) > 0);
+  return (nr > 0);  /* true iff read something */
 }
 
 
-static int g_read (lua_State *L, int *f, int first) {
+static int g_read (lua_State *L, FILE *f, int first) {
   int nargs = lua_gettop(L) - 1;
   int success;
   int n;
   if (nargs == 0) {  /* no arguments? */
-    success = _read_line(L, f);
+    success = _read_line(L, f, 1);
     n = first+1;  /* to return 1 result */
   }
   else {  /* ensure stack space for all results and for auxlib's buffer */
@@ -329,10 +476,13 @@ static int g_read (lua_State *L, int *f, int first) {
             success = read_number(L, f);
             break;
           case 'l':  /* line */
-            success = _read_line(L, f);
+            success = _read_line(L, f, 1);
+            break;
+          case 'L':  /* line with end-of-line */
+            success = _read_line(L, f, 0);
             break;
           case 'a':  /* file */
-            read_chars(L, f, ~((size_t)0));  /* read MAX_SIZE_T chars */
+            read_all(L, f);  /* read entire file */
             success = 1; /* always success */
             break;
           default:
@@ -360,14 +510,24 @@ static int f_read (lua_State *L) {
 
 
 static int io_readline (lua_State *L) {
-  int *f = (int *) lua_touserdata(L, lua_upvalueindex(1));
-  int sucess;
-  if (*f < 0)  /* file is already closed? */
-    luaL_error(L, "file is already closed");
-  sucess = _read_line(L, f);
-  if (sucess) return 1;
-  else {  /* EOF */
-    if (lua_toboolean(L, lua_upvalueindex(2))) {  /* generator created file? */
+  LStream *p = (LStream *)lua_touserdata(L, lua_upvalueindex(1));
+  int i;
+  int n = (int)lua_tointeger(L, lua_upvalueindex(2));
+  if (isclosed(p))  /* file is already closed? */
+    return luaL_error(L, "file is already closed");
+  lua_settop(L , 1);
+  for (i = 1; i <= n; i++)  /* push arguments to 'g_read' */
+    lua_pushvalue(L, lua_upvalueindex(3 + i));
+  n = g_read(L, p->f, 2);  /* 'n' is number of results */
+  lua_assert(n > 0);  /* should return at least a nil */
+  if (!lua_isnil(L, -n))  /* read at least one value? */
+    return n;  /* return them */
+  else {  /* first result is nil: EOF or error */
+    if (n > 1) {  /* is there error information? */
+      /* 2nd result is error message */
+      return luaL_error(L, "%s", lua_tostring(L, -n + 1));
+    }
+    if (lua_toboolean(L, lua_upvalueindex(3))) {  /* generator created file? */
       lua_settop(L, 0);
       lua_pushvalue(L, lua_upvalueindex(1));
       aux_close(L);  /* close it */
@@ -379,22 +539,23 @@ static int io_readline (lua_State *L) {
 /* }====================================================== */
 
 
-static int g_write (lua_State *L, int *f, int arg) {
-  int nargs = lua_gettop(L) - 1;
+static int g_write (lua_State *L, FILE *f, int arg) {
+  int nargs = lua_gettop(L) - arg;
   int status = 1;
   for (; nargs--; arg++) {
     if (lua_type(L, arg) == LUA_TNUMBER) {
       /* optimization: could be done exactly as for strings */
       status = status &&
-          rb->fdprintf(*f, LUA_NUMBER_FMT, lua_tonumber(L, arg)) > 0;
+          rb->fdprintf((int)f, LUA_NUMBER_FMT, lua_tonumber(L, arg)) > 0;
     }
     else {
       size_t l;
       const char *s = luaL_checklstring(L, arg, &l);
-      status = status && (rb->write(*f, s, l) == (ssize_t)l);
+      status = status && (rb->write((int)f, s, l) == (ssize_t)l);
     }
   }
-  return pushresult(L, status, NULL);
+  if (status) return 1;  /* file handle already on stack top */
+  else return luaL_fileresult(L, status, NULL);
 }
 
 
@@ -404,47 +565,86 @@ static int io_write (lua_State *L) {
 
 
 static int f_write (lua_State *L) {
-  return g_write(L, tofile(L), 2);
+  FILE *f = tofile(L);
+  lua_pushvalue(L, 1);  /* push file at the stack top (to be returned) */
+  return g_write(L, f, 2);
 }
 
 
 static int f_seek (lua_State *L) {
   static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END};
   static const char *const modenames[] = {"set", "cur", "end", NULL};
-  int f = *tofile(L);
+  FILE *f = tofile(L);
   int op = luaL_checkoption(L, 2, "cur", modenames);
-  long offset = luaL_optlong(L, 3, 0);
-  op = rb->lseek(f, offset, mode[op]);
+  lua_Number p3 = luaL_optnumber(L, 3, 0);
+  l_seeknum offset = (l_seeknum)p3;
+  luaL_argcheck(L, (lua_Number)offset == p3, 3,
+                  "not an integer in proper range");
+  op = rb->lseek((int)f, offset, mode[op]);
   if (op)
-    return pushresult(L, 0, NULL);  /* error */
+    return luaL_fileresult(L, 0, NULL);  /* error */
   else {
-    lua_pushinteger(L, rb->lseek(f, 0, SEEK_CUR));
+    lua_pushnumber(L, (lua_Number)rb->lseek((int)f, 0, SEEK_CUR));
     return 1;
   }
 }
 
+#if 0
+static int f_setvbuf (lua_State *L) {
+  static const int mode[] = {_IONBF, _IOFBF, _IOLBF};
+  static const char *const modenames[] = {"no", "full", "line", NULL};
+  FILE *f = tofile(L);
+  int op = luaL_checkoption(L, 2, NULL, modenames);
+  lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE);
+  int res = setvbuf(f, NULL, mode[op], sz);
+  return luaL_fileresult(L, res == 0, NULL);
+}
+
 
+
+static int io_flush (lua_State *L) {
+  return luaL_fileresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL);
+}
+
+
+static int f_flush (lua_State *L) {
+  return luaL_fileresult(L, fflush(tofile(L)) == 0, NULL);
+}
+#endif
+
+
+/*
+** functions for 'io' library
+*/
 static const luaL_Reg iolib[] = {
   {"close", io_close},
+  /*{"flush", io_flush},*/
   {"input", io_input},
   {"lines", io_lines},
   {"open", io_open},
   {"output", io_output},
+  /*{"popen", io_popen},*/
   {"read", io_read},
+  /*{"tmpfile", io_tmpfile},*/
   {"type", io_type},
   {"write", io_write},
   {NULL, NULL}
 };
 
 
+/*
+** methods for file handles
+*/
 static const luaL_Reg flib[] = {
   {"close", io_close},
+  /*{"flush", f_flush},*/
   {"lines", f_lines},
   {"read", f_read},
   {"seek", f_seek},
+  /*{"setvbuf", f_setvbuf},*/
   {"write", f_write},
-  {"__gc", io_gc},
-  {"__tostring", io_tostring},
+  {"__gc", f_gc},
+  {"__tostring", f_tostring},
   {NULL, NULL}
 };
 
@@ -453,16 +653,40 @@ static void createmeta (lua_State *L) {
   luaL_newmetatable(L, LUA_FILEHANDLE);  /* create metatable for file handles */
   lua_pushvalue(L, -1);  /* push metatable */
   lua_setfield(L, -2, "__index");  /* metatable.__index = metatable */
-  luaL_register(L, NULL, flib);  /* file methods */
+  luaL_setfuncs(L, flib, 0);  /* add file methods to new metatable */
+  lua_pop(L, 1);  /* pop new metatable */
 }
 
 
-LUALIB_API int luaopen_io (lua_State *L) {
+/*
+** function to (not) close the standard files stdin, stdout, and stderr
+*/
+#if 0
+static int io_noclose (lua_State *L) {
+  LStream *p = tolstream(L);
+  p->closef = &io_noclose;  /* keep file opened */
+  lua_pushnil(L);
+  lua_pushliteral(L, "cannot close standard file");
+  return 2;
+}
+
+
+static void createstdfile (lua_State *L, FILE *f, const char *k,
+                           const char *fname) {
+  LStream *p = newprefile(L);
+  p->f = f;
+  p->closef = &io_noclose;
+  if (k != NULL) {
+    lua_pushvalue(L, -1);
+    lua_setfield(L, LUA_REGISTRYINDEX, k);  /* add file to registry */
+  }
+  lua_setfield(L, -2, fname);  /* add file to module */
+}
+#endif
+
+LUAMOD_API int luaopen_io (lua_State *L) {
+  luaL_newlib(L, iolib);  /* new module */
   createmeta(L);
-  lua_replace(L, LUA_ENVIRONINDEX);
-  /* open library */
-  luaL_register(L, LUA_IOLIBNAME, iolib);
   /* create (and set) default files */
-  lua_pop(L, 1);  /* pop environment for default files */
   return 1;
 }