Update backports.

The backports of lstrlib.c, ltablib.c, and lutf8lib.c have been updated
to Lua version 5.3.2.

4 files changed, 485 insertions, 241 deletions

diff --git a/lprefix.h b/lprefix.h
index aa1350b..cba5bbc 100644
--- a/lprefix.h
+++ b/lprefix.h
@@ -48,6 +48,7 @@
 #undef LUAMOD_API
 #define LUAMOD_API extern
 
+
 #ifdef lutf8lib_c
 #  define luaopen_utf8 luaopen_compat53_utf8
 #  include <stdarg.h>
@@ -81,24 +82,18 @@ static const char *compat53_utf8_escape (lua_State* L, ...) {
   compat53_utf8_escape(L, l)
 #endif
 
+
 #ifdef ltablib_c
 #  define luaopen_table luaopen_compat53_table
-/* lua_rawgeti in compat53.h is implemented as a macro, so the
- * function signature doesn't match when you use a function pointer
- */
-static int compat53_rawgeti (lua_State *L, int i, lua_Integer n) {
-  return lua_rawgeti(L, i, n);
-}
-#  undef lua_rawgeti
-#  define lua_rawgeti compat53_rawgeti
-static void compat53_rawseti (lua_State *L, int i, lua_Integer n) {
-  lua_rawseti(L, i, (int)n);
-}
-#  undef lua_rawseti
-#  define lua_rawseti compat53_rawseti
+#  ifndef LUA_MAXINTEGER
+/* conservative estimate: */
+#    define LUA_MAXINTEGER INT_MAX
+#  endif
 #endif /* ltablib_c */
 
+
 #ifdef lstrlib_c
+#include <locale.h>
 #include <lualib.h>
 /* move the string library open function out of the way (we only take
  * the string packing functions)!
@@ -112,8 +107,33 @@ static void compat53_rawseti (lua_State *L, int i, lua_Integer n) {
 #  if LUA_VERSION_NUM < 503
 /* lstrlib assumes that lua_Integer and lua_Unsigned have the same
  * size, so we use the unsigned equivalent of ptrdiff_t! */
-#  define lua_Unsigned size_t
+#    define lua_Unsigned size_t
 #  endif
+#  ifndef l_mathlim
+#    ifdef LUA_NUMBER_DOUBLE
+#      define l_mathlim(n) (DBL_##n)
+#    else
+#      define l_mathlim(n) (FLT_##n)
+#    endif
+#  endif
+#  ifndef l_mathop
+#    ifdef LUA_NUMBER_DOUBLE
+#      define l_mathop(op) op
+#    else
+#      define l_mathop(op) op##f
+#    endif
+#  endif
+#  ifndef lua_getlocaledecpoint
+#    define lua_getlocaledecpoint() (localeconv()->decimal_point[0])
+#  endif
+#  ifndef l_sprintf
+#    if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
+#      define l_sprintf(s,sz,f,i) (snprintf(s, sz, f, i))
+#    else
+#      define l_sprintf(s,sz,f,i) ((void)(sz), sprintf(s, f, i))
+#    endif
+#  endif
+
 static int str_pack (lua_State *L);
 static int str_packsize (lua_State *L);
 static int str_unpack (lua_State *L);
@@ -127,12 +147,20 @@ LUAMOD_API int luaopen_compat53_string (lua_State *L) {
   luaL_newlib(L, funcs);
   return 1;
 }
+/* fake CLANG feature detection on other compilers */
+#  ifndef __has_attribute
+#    define __has_attribute(x) 0
+#  endif
 /* make luaopen_string(_XXX) static, so it (and all other referenced
  * string functions) won't be included in the resulting dll
  * (hopefully).
  */
 #  undef LUAMOD_API
-#  define LUAMOD_API static
+#  if defined(__GNUC__) || __has_attribute(__unused__)
+#    define LUAMOD_API __attribute__((__unused__)) static
+#  else
+#    define LUAMOD_API static
+#  endif
 #endif /* lstrlib.c */
 
 #endif
diff --git a/lstrlib.c b/lstrlib.c
index a650b76..fe30e34 100644
--- a/lstrlib.c
+++ b/lstrlib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lstrlib.c,v 1.221 2014/12/11 14:03:07 roberto Exp $
+** $Id: lstrlib.c,v 1.239 2015/11/25 16:28:17 roberto Exp $
 ** Standard library for string operations and pattern-matching
 ** See Copyright Notice in lua.h
 */
@@ -11,6 +11,7 @@
 
 
 #include <ctype.h>
+#include <float.h>
 #include <limits.h>
 #include <stddef.h>
 #include <stdio.h>
@@ -40,8 +41,10 @@
 ** Some sizes are better limited to fit in 'int', but must also fit in
 ** 'size_t'. (We assume that 'lua_Integer' cannot be smaller than 'int'.)
 */
+#define MAX_SIZET       ((size_t)(~(size_t)0))
+
 #define MAXSIZE  \
-        (sizeof(size_t) < sizeof(int) ? (~(size_t)0) : (size_t)(INT_MAX))
+        (sizeof(size_t) < sizeof(int) ? MAX_SIZET : (size_t)(INT_MAX))
 
 
 
@@ -70,7 +73,7 @@ static int str_sub (lua_State *L) {
   if (start < 1) start = 1;
   if (end > (lua_Integer)l) end = l;
   if (start <= end)
-    lua_pushlstring(L, s + start - 1, (size_t)(end - start + 1));
+    lua_pushlstring(L, s + start - 1, (size_t)(end - start) + 1);
   else lua_pushliteral(L, "");
   return 1;
 }
@@ -149,9 +152,9 @@ static int str_byte (lua_State *L) {
   if (posi < 1) posi = 1;
   if (pose > (lua_Integer)l) pose = l;
   if (posi > pose) return 0;  /* empty interval; return no values */
-  n = (int)(pose -  posi + 1);
-  if (posi + n <= pose)  /* arithmetic overflow? */
+  if (pose - posi >= INT_MAX)  /* arithmetic overflow? */
     return luaL_error(L, "string slice too long");
+  n = (int)(pose -  posi) + 1;
   luaL_checkstack(L, n, "string slice too long");
   for (i=0; i<n; i++)
     lua_pushinteger(L, uchar(s[posi+i-1]));
@@ -207,11 +210,12 @@ static int str_dump (lua_State *L) {
 
 
 typedef struct MatchState {
-  int matchdepth;  /* control for recursive depth (to avoid C stack overflow) */
   const char *src_init;  /* init of source string */
   const char *src_end;  /* end ('\0') of source string */
   const char *p_end;  /* end ('\0') of pattern */
   lua_State *L;
+  size_t nrep;  /* limit to avoid non-linear complexity */
+  int matchdepth;  /* control for recursive depth (to avoid C stack overflow) */
   int level;  /* total number of captures (finished or unfinished) */
   struct {
     const char *init;
@@ -230,6 +234,17 @@ static const char *match (MatchState *ms, const char *s, const char *p);
 #endif
 
 
+/*
+** parameters to control the maximum number of operators handled in
+** a match (to avoid non-linear complexity). The maximum will be:
+** (subject length) * A_REPS + B_REPS
+*/
+#if !defined(A_REPS)
+#define A_REPS          4
+#define B_REPS          100000
+#endif
+
+
 #define L_ESC           '%'
 #define SPECIALS        "^$*+?.([%-"
 
@@ -487,6 +502,8 @@ static const char *match (MatchState *ms, const char *s, const char *p) {
             s = NULL;  /* fail */
         }
         else {  /* matched once */
+          if (ms->nrep-- == 0)
+            luaL_error(ms->L, "pattern too complex");
           switch (*ep) {  /* handle optional suffix */
             case '?': {  /* optional */
               const char *res;
@@ -499,7 +516,7 @@ static const char *match (MatchState *ms, const char *s, const char *p) {
             }
             case '+':  /* 1 or more repetitions */
               s++;  /* 1 match already done */
-              /* go through */
+              /* FALLTHROUGH */
             case '*':  /* 0 or more repetitions */
               s = max_expand(ms, s, p, ep);
               break;
@@ -554,7 +571,7 @@ static void push_onecapture (MatchState *ms, int i, const char *s,
     ptrdiff_t l = ms->capture[i].len;
     if (l == CAP_UNFINISHED) luaL_error(ms->L, "unfinished capture");
     if (l == CAP_POSITION)
-      lua_pushinteger(ms->L, ms->capture[i].init - ms->src_init + 1);
+      lua_pushinteger(ms->L, (ms->capture[i].init - ms->src_init) + 1);
     else
       lua_pushlstring(ms->L, ms->capture[i].init, l);
   }
@@ -583,6 +600,26 @@ static int nospecials (const char *p, size_t l) {
 }
 
 
+static void prepstate (MatchState *ms, lua_State *L,
+                       const char *s, size_t ls, const char *p, size_t lp) {
+  ms->L = L;
+  ms->matchdepth = MAXCCALLS;
+  ms->src_init = s;
+  ms->src_end = s + ls;
+  ms->p_end = p + lp;
+  if (ls < (MAX_SIZET - B_REPS) / A_REPS)
+    ms->nrep = A_REPS * ls + B_REPS;
+  else  /* overflow (very long subject) */
+    ms->nrep = MAX_SIZET;  /* no limit */
+}
+
+
+static void reprepstate (MatchState *ms) {
+  ms->level = 0;
+  lua_assert(ms->matchdepth == MAXCCALLS);
+}
+
+
 static int str_find_aux (lua_State *L, int find) {
   size_t ls, lp;
   const char *s = luaL_checklstring(L, 1, &ls);
@@ -598,8 +635,8 @@ static int str_find_aux (lua_State *L, int find) {
     /* do a plain search */
     const char *s2 = lmemfind(s + init - 1, ls - (size_t)init + 1, p, lp);
     if (s2) {
-      lua_pushinteger(L, s2 - s + 1);
-      lua_pushinteger(L, s2 - s + lp);
+      lua_pushinteger(L, (s2 - s) + 1);
+      lua_pushinteger(L, (s2 - s) + lp);
       return 2;
     }
   }
@@ -610,18 +647,13 @@ static int str_find_aux (lua_State *L, int find) {
     if (anchor) {
       p++; lp--;  /* skip anchor character */
     }
-    ms.L = L;
-    ms.matchdepth = MAXCCALLS;
-    ms.src_init = s;
-    ms.src_end = s + ls;
-    ms.p_end = p + lp;
+    prepstate(&ms, L, s, ls, p, lp);
     do {
       const char *res;
-      ms.level = 0;
-      lua_assert(ms.matchdepth == MAXCCALLS);
+      reprepstate(&ms);
       if ((res=match(&ms, s1, p)) != NULL) {
         if (find) {
-          lua_pushinteger(L, s1 - s + 1);  /* start */
+          lua_pushinteger(L, (s1 - s) + 1);  /* start */
           lua_pushinteger(L, res - s);   /* end */
           return push_captures(&ms, NULL, 0) + 2;
         }
@@ -645,29 +677,26 @@ static int str_match (lua_State *L) {
 }
 
 
+/* state for 'gmatch' */
+typedef struct GMatchState {
+  const char *src;  /* current position */
+  const char *p;  /* pattern */
+  MatchState ms;  /* match state */
+} GMatchState;
+
+
 static int gmatch_aux (lua_State *L) {
-  MatchState ms;
-  size_t ls, lp;
-  const char *s = lua_tolstring(L, lua_upvalueindex(1), &ls);
-  const char *p = lua_tolstring(L, lua_upvalueindex(2), &lp);
+  GMatchState *gm = (GMatchState *)lua_touserdata(L, lua_upvalueindex(3));
   const char *src;
-  ms.L = L;
-  ms.matchdepth = MAXCCALLS;
-  ms.src_init = s;
-  ms.src_end = s+ls;
-  ms.p_end = p + lp;
-  for (src = s + (size_t)lua_tointeger(L, lua_upvalueindex(3));
-       src <= ms.src_end;
-       src++) {
+  for (src = gm->src; src <= gm->ms.src_end; src++) {
     const char *e;
-    ms.level = 0;
-    lua_assert(ms.matchdepth == MAXCCALLS);
-    if ((e = match(&ms, src, p)) != NULL) {
-      lua_Integer newstart = e-s;
-      if (e == src) newstart++;  /* empty match? go at least one position */
-      lua_pushinteger(L, newstart);
-      lua_replace(L, lua_upvalueindex(3));
-      return push_captures(&ms, src, e);
+    reprepstate(&gm->ms);
+    if ((e = match(&gm->ms, src, gm->p)) != NULL) {
+      if (e == src)  /* empty match? */
+        gm->src =src + 1;  /* go at least one position */
+      else
+        gm->src = e;
+      return push_captures(&gm->ms, src, e);
     }
   }
   return 0;  /* not found */
@@ -675,10 +704,14 @@ static int gmatch_aux (lua_State *L) {
 
 
 static int gmatch (lua_State *L) {
-  luaL_checkstring(L, 1);
-  luaL_checkstring(L, 2);
-  lua_settop(L, 2);
-  lua_pushinteger(L, 0);
+  size_t ls, lp;
+  const char *s = luaL_checklstring(L, 1, &ls);
+  const char *p = luaL_checklstring(L, 2, &lp);
+  GMatchState *gm;
+  lua_settop(L, 2);  /* keep them on closure to avoid being collected */
+  gm = (GMatchState *)lua_newuserdata(L, sizeof(GMatchState));
+  prepstate(&gm->ms, L, s, ls, p, lp);
+  gm->src = s; gm->p = p;
   lua_pushcclosure(L, gmatch_aux, 3);
   return 1;
 }
@@ -760,17 +793,11 @@ static int str_gsub (lua_State *L) {
   if (anchor) {
     p++; lp--;  /* skip anchor character */
   }
-  ms.L = L;
-  ms.matchdepth = MAXCCALLS;
-  ms.src_init = src;
-  ms.src_end = src+srcl;
-  ms.p_end = p + lp;
+  prepstate(&ms, L, src, srcl, p, lp);
   while (n < max_s) {
     const char *e;
-    ms.level = 0;
-    lua_assert(ms.matchdepth == MAXCCALLS);
-    e = match(&ms, src, p);
-    if (e) {
+    reprepstate(&ms);
+    if ((e = match(&ms, src, p)) != NULL) {
       n++;
       add_value(&ms, &b, src, e, tr);
     }
@@ -797,17 +824,102 @@ static int str_gsub (lua_State *L) {
 ** =======================================================
 */
 
-/* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */
-#define MAX_ITEM        512
+#if !defined(lua_number2strx)   /* { */
+
+/*
+** Hexadecimal floating-point formatter
+*/
+
+#include <locale.h>
+#include <math.h>
+
+#define SIZELENMOD      (sizeof(LUA_NUMBER_FRMLEN)/sizeof(char))
+
+
+/*
+** Number of bits that goes into the first digit. It can be any value
+** between 1 and 4; the following definition tries to align the number
+** to nibble boundaries by making what is left after that first digit a
+** multiple of 4.
+*/
+#define L_NBFD          ((l_mathlim(MANT_DIG) - 1)%4 + 1)
+
+
+/*
+** Add integer part of 'x' to buffer and return new 'x'
+*/
+static lua_Number adddigit (char *buff, int n, lua_Number x) {
+  lua_Number dd = l_mathop(floor)(x);  /* get integer part from 'x' */
+  int d = (int)dd;
+  buff[n] = (d < 10 ? d + '0' : d - 10 + 'a');  /* add to buffer */
+  return x - dd;  /* return what is left */
+}
+
+
+static int num2straux (char *buff, int sz, lua_Number x) {
+  if (x != x || x == HUGE_VAL || x == -HUGE_VAL)  /* inf or NaN? */
+    return l_sprintf(buff, sz, LUA_NUMBER_FMT, x);  /* equal to '%g' */
+  else if (x == 0) {  /* can be -0... */
+    /* create "0" or "-0" followed by exponent */
+    return l_sprintf(buff, sz, LUA_NUMBER_FMT "x0p+0", x);
+  }
+  else {
+    int e;
+    lua_Number m = l_mathop(frexp)(x, &e);  /* 'x' fraction and exponent */
+    int n = 0;  /* character count */
+    if (m < 0) {  /* is number negative? */
+      buff[n++] = '-';  /* add signal */
+      m = -m;  /* make it positive */
+    }
+    buff[n++] = '0'; buff[n++] = 'x';  /* add "0x" */
+    m = adddigit(buff, n++, m * (1 << L_NBFD));  /* add first digit */
+    e -= L_NBFD;  /* this digit goes before the radix point */
+    if (m > 0) {  /* more digits? */
+      buff[n++] = lua_getlocaledecpoint();  /* add radix point */
+      do {  /* add as many digits as needed */
+        m = adddigit(buff, n++, m * 16);
+      } while (m > 0);
+    }
+    n += l_sprintf(buff + n, sz - n, "p%+d", e);  /* add exponent */
+    lua_assert(n < sz);
+    return n;
+  }
+}
+
+
+static int lua_number2strx (lua_State *L, char *buff, int sz,
+                            const char *fmt, lua_Number x) {
+  int n = num2straux(buff, sz, x);
+  if (fmt[SIZELENMOD] == 'A') {
+    int i;
+    for (i = 0; i < n; i++)
+      buff[i] = toupper(uchar(buff[i]));
+  }
+  else if (fmt[SIZELENMOD] != 'a')
+    luaL_error(L, "modifiers for format '%%a'/'%%A' not implemented");
+  return n;
+}
+
+#endif                          /* } */
+
+
+/*
+** Maximum size of each formatted item. This maximum size is produced
+** by format('%.99f', -maxfloat), and is equal to 99 + 3 ('-', '.',
+** and '\0') + number of decimal digits to represent maxfloat (which
+** is maximum exponent + 1). (99+3+1 then rounded to 120 for "extra
+** expenses", such as locale-dependent stuff)
+*/
+#define MAX_ITEM        (120 + l_mathlim(MAX_10_EXP))
+
 
 /* valid flags in a format specification */
 #define FLAGS   "-+ #0"
 
 /*
 ** maximum size of each format specification (such as "%-099.99d")
-** (+2 for length modifiers; +10 accounts for %99.99x plus margin of error)
 */
-#define MAX_FORMAT      (sizeof(FLAGS) + 2 + 10)
+#define MAX_FORMAT      32
 
 
 static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {
@@ -822,9 +934,9 @@ static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {
     else if (*s == '\0' || iscntrl(uchar(*s))) {
       char buff[10];
       if (!isdigit(uchar(*(s+1))))
-        sprintf(buff, "\\%d", (int)uchar(*s));
+        l_sprintf(buff, sizeof(buff), "\\%d", (int)uchar(*s));
       else
-        sprintf(buff, "\\%03d", (int)uchar(*s));
+        l_sprintf(buff, sizeof(buff), "\\%03d", (int)uchar(*s));
       luaL_addstring(b, buff);
     }
     else
@@ -849,8 +961,8 @@ static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {
   if (isdigit(uchar(*p)))
     luaL_error(L, "invalid format (width or precision too long)");
   *(form++) = '%';
-  memcpy(form, strfrmt, (p - strfrmt + 1) * sizeof(char));
-  form += p - strfrmt + 1;
+  memcpy(form, strfrmt, ((p - strfrmt) + 1) * sizeof(char));
+  form += (p - strfrmt) + 1;
   *form = '\0';
   return p;
 }
@@ -891,23 +1003,25 @@ static int str_format (lua_State *L) {
       strfrmt = scanformat(L, strfrmt, form);
       switch (*strfrmt++) {
         case 'c': {
-          nb = sprintf(buff, form, (int)luaL_checkinteger(L, arg));
+          nb = l_sprintf(buff, MAX_ITEM, form, (int)luaL_checkinteger(L, arg));
           break;
         }
         case 'd': case 'i':
         case 'o': case 'u': case 'x': case 'X': {
           lua_Integer n = luaL_checkinteger(L, arg);
           addlenmod(form, LUA_INTEGER_FRMLEN);
-          nb = sprintf(buff, form, n);
+          nb = l_sprintf(buff, MAX_ITEM, form, n);
           break;
         }
-#if defined(LUA_USE_AFORMAT)
         case 'a': case 'A':
-#endif
+          addlenmod(form, LUA_NUMBER_FRMLEN);
+          nb = lua_number2strx(L, buff, MAX_ITEM, form,
+                                  luaL_checknumber(L, arg));
+          break;
         case 'e': case 'E': case 'f':
         case 'g': case 'G': {
           addlenmod(form, LUA_NUMBER_FRMLEN);
-          nb = sprintf(buff, form, luaL_checknumber(L, arg));
+          nb = l_sprintf(buff, MAX_ITEM, form, luaL_checknumber(L, arg));
           break;
         }
         case 'q': {
@@ -917,23 +1031,27 @@ static int str_format (lua_State *L) {
         case 's': {
           size_t l;
           const char *s = luaL_tolstring(L, arg, &l);
-          if (!strchr(form, '.') && l >= 100) {
-            /* no precision and string is too long to be formatted;
-               keep original string */
-            luaL_addvalue(&b);
-            break;
-          }
+          if (form[2] == '\0')  /* no modifiers? */
+            luaL_addvalue(&b);  /* keep entire string */
           else {
-            nb = sprintf(buff, form, s);
-            lua_pop(L, 1);  /* remove result from 'luaL_tolstring' */
-            break;
+            luaL_argcheck(L, l == strlen(s), arg, "string contains zeros");
+            if (!strchr(form, '.') && l >= 100) {
+              /* no precision and string is too long to be formatted */
+              luaL_addvalue(&b);  /* keep entire string */
+            }
+            else {  /* format the string into 'buff' */
+              nb = l_sprintf(buff, MAX_ITEM, form, s);
+              lua_pop(L, 1);  /* remove result from 'luaL_tolstring' */
+            }
           }
+          break;
         }
         default: {  /* also treat cases 'pnLlh' */
           return luaL_error(L, "invalid option '%%%c' to 'format'",
                                *(strfrmt - 1));
         }
       }
+      lua_assert(nb < MAX_ITEM);
       luaL_addsize(&b, nb);
     }
   }
@@ -1225,8 +1343,13 @@ static int str_pack (lua_State *L) {
       case Kchar: {  /* fixed-size string */
         size_t len;
         const char *s = luaL_checklstring(L, arg, &len);
-        luaL_argcheck(L, len == (size_t)size, arg, "wrong length");
-        luaL_addlstring(&b, s, size);
+        if ((size_t)size <= len)  /* string larger than (or equal to) needed? */
+          luaL_addlstring(&b, s, size);  /* truncate string to asked size */
+        else {  /* string smaller than needed */
+          luaL_addlstring(&b, s, len);  /* add it all */
+          while (len++ < (size_t)size)  /* pad extra space */
+            luaL_addchar(&b, LUA_PACKPADBYTE);
+        }
         break;
       }
       case Kstring: {  /* strings with length count */
@@ -1249,7 +1372,7 @@ static int str_pack (lua_State *L) {
         totalsize += len + 1;
         break;
       }
-      case Kpadding: luaL_addchar(&b, LUA_PACKPADBYTE);  /* go through */
+      case Kpadding: luaL_addchar(&b, LUA_PACKPADBYTE);  /* FALLTHROUGH */
       case Kpaddalign: case Knop:
         arg--;  /* undo increment */
         break;
@@ -1276,7 +1399,7 @@ static int str_packsize (lua_State *L) {
       case Kstring:  /* strings with length count */
       case Kzstr:    /* zero-terminated string */
         luaL_argerror(L, 1, "variable-length format");
-        break;
+        /* call never return, but to avoid warnings: *//* FALLTHROUGH */
       default:  break;
     }
   }
diff --git a/ltablib.c b/ltablib.c
index 8f78afb..b3c9a7c 100644
--- a/ltablib.c
+++ b/ltablib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ltablib.c,v 1.79 2014/11/02 19:19:04 roberto Exp $
+** $Id: ltablib.c,v 1.90 2015/11/25 12:48:57 roberto Exp $
 ** Library for Table Manipulation
 ** See Copyright Notice in lua.h
 */
@@ -12,6 +12,7 @@
 
 #include <limits.h>
 #include <stddef.h>
+#include <string.h>
 
 #include "lua.h"
 
@@ -19,42 +20,44 @@
 #include "lualib.h"
 
 
-
 /*
-** Structure with table-access functions
+** Operations that an object must define to mimic a table
+** (some functions only need some of them)
 */
-typedef struct {
-  int (*geti) (lua_State *L, int idx, lua_Integer n);
-  void (*seti) (lua_State *L, int idx, lua_Integer n);
-} TabA;
+#define TAB_R   1                       /* read */
+#define TAB_W   2                       /* write */
+#define TAB_L   4                       /* length */
+#define TAB_RW  (TAB_R | TAB_W)         /* read/write */
+
+
+#define aux_getn(L,n,w) (checktab(L, n, (w) | TAB_L), luaL_len(L, n))
+
+
+static int checkfield (lua_State *L, const char *key, int n) {
+  lua_pushstring(L, key);
+  return (lua_rawget(L, -n) != LUA_TNIL);
+}
 
 
 /*
-** Check that 'arg' has a table and set access functions in 'ta' to raw
-** or non-raw according to the presence of corresponding metamethods.
+** Check that 'arg' either is a table or can behave like one (that is,
+** has a metatable with the required metamethods)
 */
-static void checktab (lua_State *L, int arg, TabA *ta) {
-  ta->geti = NULL; ta->seti = NULL;
-  if (lua_getmetatable(L, arg)) {
-    lua_pushliteral(L, "__index");  /* 'index' metamethod */
-    if (lua_rawget(L, -2) != LUA_TNIL)
-      ta->geti = lua_geti;
-    lua_pushliteral(L, "__newindex");  /* 'newindex' metamethod */
-    if (lua_rawget(L, -3) != LUA_TNIL)
-      ta->seti = lua_seti;
-    lua_pop(L, 3);  /* pop metatable plus both metamethods */
-  }
-  if (ta->geti == NULL || ta->seti == NULL) {
-    luaL_checktype(L, arg, LUA_TTABLE);  /* must be table for raw methods */
-    if (ta->geti == NULL) ta->geti = lua_rawgeti;
-    if (ta->seti == NULL) ta->seti = lua_rawseti;
+static void checktab (lua_State *L, int arg, int what) {
+  if (lua_type(L, arg) != LUA_TTABLE) {  /* is it not a table? */
+    int n = 1;  /* number of elements to pop */
+    if (lua_getmetatable(L, arg) &&  /* must have metatable */
+        (!(what & TAB_R) || checkfield(L, "__index", ++n)) &&
+        (!(what & TAB_W) || checkfield(L, "__newindex", ++n)) &&
+        (!(what & TAB_L) || checkfield(L, "__len", ++n))) {
+      lua_pop(L, n);  /* pop metatable and tested metamethods */
+    }
+    else
+      luaL_argerror(L, arg, "table expected");  /* force an error */
   }
 }
 
 
-#define aux_getn(L,n,ta)        (checktab(L, n, ta), luaL_len(L, n))
-
-
 #if defined(LUA_COMPAT_MAXN)
 static int maxn (lua_State *L) {
   lua_Number max = 0;
@@ -74,8 +77,7 @@ static int maxn (lua_State *L) {
 
 
 static int tinsert (lua_State *L) {
-  TabA ta;
-  lua_Integer e = aux_getn(L, 1, &ta) + 1;  /* first empty element */
+  lua_Integer e = aux_getn(L, 1, TAB_RW) + 1;  /* first empty element */
   lua_Integer pos;  /* where to insert new element */
   switch (lua_gettop(L)) {
     case 2: {  /* called with only 2 arguments */
@@ -87,8 +89,8 @@ static int tinsert (lua_State *L) {
       pos = luaL_checkinteger(L, 2);  /* 2nd argument is the position */
       luaL_argcheck(L, 1 <= pos && pos <= e, 2, "position out of bounds");
       for (i = e; i > pos; i--) {  /* move up elements */
-        (*ta.geti)(L, 1, i - 1);
-        (*ta.seti)(L, 1, i);  /* t[i] = t[i - 1] */
+        lua_geti(L, 1, i - 1);
+        lua_seti(L, 1, i);  /* t[i] = t[i - 1] */
       }
       break;
     }
@@ -96,55 +98,57 @@ static int tinsert (lua_State *L) {
       return luaL_error(L, "wrong number of arguments to 'insert'");
     }
   }
-  (*ta.seti)(L, 1, pos);  /* t[pos] = v */
+  lua_seti(L, 1, pos);  /* t[pos] = v */
   return 0;
 }
 
 
 static int tremove (lua_State *L) {
-  TabA ta;
-  lua_Integer size = aux_getn(L, 1, &ta);
+  lua_Integer size = aux_getn(L, 1, TAB_RW);
   lua_Integer pos = luaL_optinteger(L, 2, size);
   if (pos != size)  /* validate 'pos' if given */
     luaL_argcheck(L, 1 <= pos && pos <= size + 1, 1, "position out of bounds");
-  (*ta.geti)(L, 1, pos);  /* result = t[pos] */
+  lua_geti(L, 1, pos);  /* result = t[pos] */
   for ( ; pos < size; pos++) {
-    (*ta.geti)(L, 1, pos + 1);
-    (*ta.seti)(L, 1, pos);  /* t[pos] = t[pos + 1] */
+    lua_geti(L, 1, pos + 1);
+    lua_seti(L, 1, pos);  /* t[pos] = t[pos + 1] */
   }
   lua_pushnil(L);
-  (*ta.seti)(L, 1, pos);  /* t[pos] = nil */
+  lua_seti(L, 1, pos);  /* t[pos] = nil */
   return 1;
 }
 
 
+/*
+** Copy elements (1[f], ..., 1[e]) into (tt[t], tt[t+1], ...). Whenever
+** possible, copy in increasing order, which is better for rehashing.
+** "possible" means destination after original range, or smaller
+** than origin, or copying to another table.
+*/
 static int tmove (lua_State *L) {
-  TabA ta;
   lua_Integer f = luaL_checkinteger(L, 2);
   lua_Integer e = luaL_checkinteger(L, 3);
   lua_Integer t = luaL_checkinteger(L, 4);
   int tt = !lua_isnoneornil(L, 5) ? 5 : 1;  /* destination table */
-  /* the following restriction avoids several problems with overflows */
-  luaL_argcheck(L, f > 0, 2, "initial position must be positive");
+  checktab(L, 1, TAB_R);
+  checktab(L, tt, TAB_W);
   if (e >= f) {  /* otherwise, nothing to move */
     lua_Integer n, i;
-    ta.geti = (luaL_getmetafield(L, 1, "__index") == LUA_TNIL)
-      ? (luaL_checktype(L, 1, LUA_TTABLE), lua_rawgeti)
-      : lua_geti;
-    ta.seti = (luaL_getmetafield(L, tt, "__newindex") == LUA_TNIL)
-      ? (luaL_checktype(L, tt, LUA_TTABLE), lua_rawseti)
-      : lua_seti;
+    luaL_argcheck(L, f > 0 || e < LUA_MAXINTEGER + f, 3,
+                  "too many elements to move");
     n = e - f + 1;  /* number of elements to move */
-    if (t > f) {
-      for (i = n - 1; i >= 0; i--) {
-        (*ta.geti)(L, 1, f + i);
-        (*ta.seti)(L, tt, t + i);
+    luaL_argcheck(L, t <= LUA_MAXINTEGER - n + 1, 4,
+                  "destination wrap around");
+    if (t > e || t <= f || tt != 1) {
+      for (i = 0; i < n; i++) {
+        lua_geti(L, 1, f + i);
+        lua_seti(L, tt, t + i);
       }
     }
     else {
-      for (i = 0; i < n; i++) {
-        (*ta.geti)(L, 1, f + i);
-        (*ta.seti)(L, tt, t + i);
+      for (i = n - 1; i >= 0; i--) {
+        lua_geti(L, 1, f + i);
+        lua_seti(L, tt, t + i);
       }
     }
   }
@@ -153,8 +157,8 @@ static int tmove (lua_State *L) {
 }
 
 
-static void addfield (lua_State *L, luaL_Buffer *b, TabA *ta, lua_Integer i) {
-  (*ta->geti)(L, 1, i);
+static void addfield (lua_State *L, luaL_Buffer *b, lua_Integer i) {
+  lua_geti(L, 1, i);
   if (!lua_isstring(L, -1))
     luaL_error(L, "invalid value (%s) at index %d in table for 'concat'",
                   luaL_typename(L, -1), i);
@@ -163,21 +167,19 @@ static void addfield (lua_State *L, luaL_Buffer *b, TabA *ta, lua_Integer i) {
 
 
 static int tconcat (lua_State *L) {
-  TabA ta;
   luaL_Buffer b;
+  lua_Integer last = aux_getn(L, 1, TAB_R);
   size_t lsep;
-  lua_Integer i, last;
   const char *sep = luaL_optlstring(L, 2, "", &lsep);
-  checktab(L, 1, &ta);
-  i = luaL_optinteger(L, 3, 1);
-  last = luaL_opt(L, luaL_checkinteger, 4, luaL_len(L, 1));
+  lua_Integer i = luaL_optinteger(L, 3, 1);
+  last = luaL_opt(L, luaL_checkinteger, 4, last);
   luaL_buffinit(L, &b);
   for (; i < last; i++) {
-    addfield(L, &b, &ta, i);
+    addfield(L, &b, i);
     luaL_addlstring(&b, sep, lsep);
   }
   if (i == last)  /* add last value (if interval was not empty) */
-    addfield(L, &b, &ta, i);
+    addfield(L, &b, i);
   luaL_pushresult(&b);
   return 1;
 }
@@ -195,7 +197,7 @@ static int pack (lua_State *L) {
   lua_createtable(L, n, 1);  /* create result table */
   lua_insert(L, 1);  /* put it at index 1 */
   for (i = n; i >= 1; i--)  /* assign elements */
-    lua_rawseti(L, 1, i);
+    lua_seti(L, 1, i);
   lua_pushinteger(L, n);
   lua_setfield(L, 1, "n");  /* t.n = number of elements */
   return 1;  /* return table */
@@ -203,20 +205,17 @@ static int pack (lua_State *L) {
 
 
 static int unpack (lua_State *L) {
-  TabA ta;
-  lua_Integer i, e;
   lua_Unsigned n;
-  checktab(L, 1, &ta);
-  i = luaL_optinteger(L, 2, 1);
-  e = luaL_opt(L, luaL_checkinteger, 3, luaL_len(L, 1));
+  lua_Integer i = luaL_optinteger(L, 2, 1);
+  lua_Integer e = luaL_opt(L, luaL_checkinteger, 3, luaL_len(L, 1));
   if (i > e) return 0;  /* empty range */
   n = (lua_Unsigned)e - i;  /* number of elements minus 1 (avoid overflows) */
   if (n >= (unsigned int)INT_MAX  || !lua_checkstack(L, (int)(++n)))
     return luaL_error(L, "too many results to unpack");
-  do {  /* must have at least one element */
-    (*ta.geti)(L, 1, i);  /* push arg[i..e] */
-  } while (i++ < e); 
-
+  for (; i < e; i++) {  /* push arg[i..e - 1] (to avoid overflows) */
+    lua_geti(L, 1, i);
+  }
+  lua_geti(L, 1, e);  /* push last element */
   return (int)n;
 }
 
@@ -233,97 +232,190 @@ static int unpack (lua_State *L) {
 */
 
 
-static void set2 (lua_State *L, TabA *ta, int i, int j) {
-  (*ta->seti)(L, 1, i);
-  (*ta->seti)(L, 1, j);
+/*
+** Produce a "random" 'unsigned int' to randomize pivot choice. This
+** macro is used only when 'sort' detects a big imbalance in the result
+** of a partition. (If you don't want/need this "randomness", ~0 is a
+** good choice.)
+*/
+#if !defined(l_randomizePivot)          /* { */
+
+#include <time.h>
+
+/* size of 'e' measured in number of 'unsigned int's */
+#define sof(e)          (sizeof(e) / sizeof(unsigned int))
+
+/*
+** Use 'time' and 'clock' as sources of "randomness". Because we don't
+** know the types 'clock_t' and 'time_t', we cannot cast them to
+** anything without risking overflows. A safe way to use their values
+** is to copy them to an array of a known type and use the array values.
+*/
+static unsigned int l_randomizePivot (void) {
+  clock_t c = clock();
+  time_t t = time(NULL);
+  unsigned int buff[sof(c) + sof(t)];
+  unsigned int i, rnd = 0;
+  memcpy(buff, &c, sof(c) * sizeof(unsigned int));
+  memcpy(buff + sof(c), &t, sof(t) * sizeof(unsigned int));
+  for (i = 0; i < sof(buff); i++)
+    rnd += buff[i];
+  return rnd;
+}
+
+#endif                                  /* } */
+
+
+/* arrays larger than 'RANLIMIT' may use randomized pivots */
+#define RANLIMIT        100u
+
+
+static void set2 (lua_State *L, unsigned int i, unsigned int j) {
+  lua_seti(L, 1, i);
+  lua_seti(L, 1, j);
 }
 
+
+/*
+** Return true iff value at stack index 'a' is less than the value at
+** index 'b' (according to the order of the sort).
+*/
 static int sort_comp (lua_State *L, int a, int b) {
-  if (!lua_isnil(L, 2)) {  /* function? */
+  if (lua_isnil(L, 2))  /* no function? */
+    return lua_compare(L, a, b, LUA_OPLT);  /* a < b */
+  else {  /* function */
     int res;
-    lua_pushvalue(L, 2);
+    lua_pushvalue(L, 2);    /* push function */
     lua_pushvalue(L, a-1);  /* -1 to compensate function */
     lua_pushvalue(L, b-2);  /* -2 to compensate function and 'a' */
-    lua_call(L, 2, 1);
-    res = lua_toboolean(L, -1);
-    lua_pop(L, 1);
+    lua_call(L, 2, 1);      /* call function */
+    res = lua_toboolean(L, -1);  /* get result */
+    lua_pop(L, 1);          /* pop result */
     return res;
   }
-  else  /* a < b? */
-    return lua_compare(L, a, b, LUA_OPLT);
 }
 
-static void auxsort (lua_State *L, TabA *ta, int l, int u) {
-  while (l < u) {  /* for tail recursion */
-    int i, j;
-    /* sort elements a[l], a[(l+u)/2] and a[u] */
-    (*ta->geti)(L, 1, l);
-    (*ta->geti)(L, 1, u);
-    if (sort_comp(L, -1, -2))  /* a[u] < a[l]? */
-      set2(L, ta, l, u);  /* swap a[l] - a[u] */
+
+/*
+** Does the partition: Pivot P is at the top of the stack.
+** precondition: a[lo] <= P == a[up-1] <= a[up],
+** so it only needs to do the partition from lo + 1 to up - 2.
+** Pos-condition: a[lo .. i - 1] <= a[i] == P <= a[i + 1 .. up]
+** returns 'i'.
+*/
+static unsigned int partition (lua_State *L, unsigned int lo,
+                                             unsigned int up) {
+  unsigned int i = lo;  /* will be incremented before first use */
+  unsigned int j = up - 1;  /* will be decremented before first use */
+  /* loop invariant: a[lo .. i] <= P <= a[j .. up] */
+  for (;;) {
+    /* next loop: repeat ++i while a[i] < P */
+    while (lua_geti(L, 1, ++i), sort_comp(L, -1, -2)) {
+      if (i == up - 1)  /* a[i] < P  but a[up - 1] == P  ?? */
+        luaL_error(L, "invalid order function for sorting");
+      lua_pop(L, 1);  /* remove a[i] */
+    }
+    /* after the loop, a[i] >= P and a[lo .. i - 1] < P */
+    /* next loop: repeat --j while P < a[j] */
+    while (lua_geti(L, 1, --j), sort_comp(L, -3, -1)) {
+      if (j < i)  /* j < i  but  a[j] > P ?? */
+        luaL_error(L, "invalid order function for sorting");
+      lua_pop(L, 1);  /* remove a[j] */
+    }
+    /* after the loop, a[j] <= P and a[j + 1 .. up] >= P */
+    if (j < i) {  /* no elements out of place? */
+      /* a[lo .. i - 1] <= P <= a[j + 1 .. i .. up] */
+      lua_pop(L, 1);  /* pop a[j] */
+      /* swap pivot (a[up - 1]) with a[i] to satisfy pos-condition */
+      set2(L, up - 1, i);
+      return i;
+    }
+    /* otherwise, swap a[i] - a[j] to restore invariant and repeat */
+    set2(L, i, j);
+  }
+}
+
+
+/*
+** Choose an element in the middle (2nd-3th quarters) of [lo,up]
+** "randomized" by 'rnd'
+*/
+static unsigned int choosePivot (unsigned int lo, unsigned int up,
+                                 unsigned int rnd) {
+  unsigned int r4 = (unsigned int)(up - lo) / 4u;  /* range/4 */
+  unsigned int p = rnd % (r4 * 2) + (lo + r4);
+  lua_assert(lo + r4 <= p && p <= up - r4);
+  return p;
+}
+
+
+/*
+** QuickSort algorithm (recursive function)
+*/
+static void auxsort (lua_State *L, unsigned int lo, unsigned int up,
+                                   unsigned int rnd) {
+  while (lo < up) {  /* loop for tail recursion */
+    unsigned int p;  /* Pivot index */
+    unsigned int n;  /* to be used later */
+    /* sort elements 'lo', 'p', and 'up' */
+    lua_geti(L, 1, lo);
+    lua_geti(L, 1, up);
+    if (sort_comp(L, -1, -2))  /* a[up] < a[lo]? */
+      set2(L, lo, up);  /* swap a[lo] - a[up] */
     else
-      lua_pop(L, 2);
-    if (u-l == 1) break;  /* only 2 elements */
-    i = (l+u)/2;
-    (*ta->geti)(L, 1, i);
-    (*ta->geti)(L, 1, l);
-    if (sort_comp(L, -2, -1))  /* a[i]<a[l]? */
-      set2(L, ta, i, l);
+      lua_pop(L, 2);  /* remove both values */
+    if (up - lo == 1)  /* only 2 elements? */
+      return;  /* already sorted */
+    if (up - lo < RANLIMIT || rnd == 0)  /* small interval or no randomize? */
+      p = (lo + up)/2;  /* middle element is a good pivot */
+    else  /* for larger intervals, it is worth a random pivot */
+      p = choosePivot(lo, up, rnd);
+    lua_geti(L, 1, p);
+    lua_geti(L, 1, lo);
+    if (sort_comp(L, -2, -1))  /* a[p] < a[lo]? */
+      set2(L, p, lo);  /* swap a[p] - a[lo] */
     else {
-      lua_pop(L, 1);  /* remove a[l] */
-      (*ta->geti)(L, 1, u);
-      if (sort_comp(L, -1, -2))  /* a[u]<a[i]? */
-        set2(L, ta, i, u);
+      lua_pop(L, 1);  /* remove a[lo] */
+      lua_geti(L, 1, up);
+      if (sort_comp(L, -1, -2))  /* a[up] < a[p]? */
+        set2(L, p, up);  /* swap a[up] - a[p] */
       else
         lua_pop(L, 2);
     }
-    if (u-l == 2) break;  /* only 3 elements */
-    (*ta->geti)(L, 1, i);  /* Pivot */
-    lua_pushvalue(L, -1);
-    (*ta->geti)(L, 1, u-1);
-    set2(L, ta, i, u-1);
-    /* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */
-    i = l; j = u-1;
-    for (;;) {  /* invariant: a[l..i] <= P <= a[j..u] */
-      /* repeat ++i until a[i] >= P */
-      while ((*ta->geti)(L, 1, ++i), sort_comp(L, -1, -2)) {
-        if (i>=u) luaL_error(L, "invalid order function for sorting");
-        lua_pop(L, 1);  /* remove a[i] */
-      }
-      /* repeat --j until a[j] <= P */
-      while ((*ta->geti)(L, 1, --j), sort_comp(L, -3, -1)) {
-        if (j<=l) luaL_error(L, "invalid order function for sorting");
-        lua_pop(L, 1);  /* remove a[j] */
-      }
-      if (j<i) {
-        lua_pop(L, 3);  /* pop pivot, a[i], a[j] */
-        break;
-      }
-      set2(L, ta, i, j);
-    }
-    (*ta->geti)(L, 1, u-1);
-    (*ta->geti)(L, 1, i);
-    set2(L, ta, u-1, i);  /* swap pivot (a[u-1]) with a[i] */
-    /* a[l..i-1] <= a[i] == P <= a[i+1..u] */
-    /* adjust so that smaller half is in [j..i] and larger one in [l..u] */
-    if (i-l < u-i) {
-      j=l; i=i-1; l=i+2;
+    if (up - lo == 2)  /* only 3 elements? */
+      return;  /* already sorted */
+    lua_geti(L, 1, p);  /* get middle element (Pivot) */
+    lua_pushvalue(L, -1);  /* push Pivot */
+    lua_geti(L, 1, up - 1);  /* push a[up - 1] */
+    set2(L, p, up - 1);  /* swap Pivot (a[p]) with a[up - 1] */
+    p = partition(L, lo, up);
+    /* a[lo .. p - 1] <= a[p] == P <= a[p + 1 .. up] */
+    if (p - lo < up - p) {  /* lower interval is smaller? */
+      auxsort(L, lo, p - 1, rnd);  /* call recursively for lower interval */
+      n = p - lo;  /* size of smaller interval */
+      lo = p + 1;  /* tail call for [p + 1 .. up] (upper interval) */
     }
     else {
-      j=i+1; i=u; u=j-2;
+      auxsort(L, p + 1, up, rnd);  /* call recursively for upper interval */
+      n = up - p;  /* size of smaller interval */
+      up = p - 1;  /* tail call for [lo .. p - 1]  (lower interval) */
     }
-    auxsort(L, ta, j, i);  /* call recursively the smaller one */
-  }  /* repeat the routine for the larger one */
+    if ((up - lo) / 128u > n) /* partition too imbalanced? */
+      rnd = l_randomizePivot();  /* try a new randomization */
+  }  /* tail call auxsort(L, lo, up, rnd) */
 }
 
+
 static int sort (lua_State *L) {
-  TabA ta;
-  int n = (int)aux_getn(L, 1, &ta);
-  luaL_checkstack(L, 50, "");  /* assume array is smaller than 2^50 */
-  if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
-    luaL_checktype(L, 2, LUA_TFUNCTION);
-  lua_settop(L, 2);  /* make sure there are two arguments */
-  auxsort(L, &ta, 1, n);
+  lua_Integer n = aux_getn(L, 1, TAB_RW);
+  if (n > 1) {  /* non-trivial interval? */
+    luaL_argcheck(L, n < INT_MAX, 1, "array too big");
+    luaL_checkstack(L, 40, "");  /* assume array is smaller than 2^40 */
+    if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
+      luaL_checktype(L, 2, LUA_TFUNCTION);  /* must be a function */
+    lua_settop(L, 2);  /* make sure there are two arguments */
+    auxsort(L, 1, (unsigned int)n, 0u);
+  }
   return 0;
 }
 
diff --git a/lutf8lib.c b/lutf8lib.c
index be4f087..9042582 100644
--- a/lutf8lib.c
+++ b/lutf8lib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lutf8lib.c,v 1.13 2014/11/02 19:19:04 roberto Exp $
+** $Id: lutf8lib.c,v 1.15 2015/03/28 19:16:55 roberto Exp $
 ** Standard library for UTF-8 manipulation
 ** See Copyright Notice in lua.h
 */
@@ -11,6 +11,7 @@
 
 
 #include <assert.h>
+#include <limits.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -37,7 +38,7 @@ static lua_Integer u_posrelat (lua_Integer pos, size_t len) {
 ** Decode one UTF-8 sequence, returning NULL if byte sequence is invalid.
 */
 static const char *utf8_decode (const char *o, int *val) {
-  static unsigned int limits[] = {0xFF, 0x7F, 0x7FF, 0xFFFF};
+  static const unsigned int limits[] = {0xFF, 0x7F, 0x7FF, 0xFFFF};
   const unsigned char *s = (const unsigned char *)o;
   unsigned int c = s[0];
   unsigned int res = 0;  /* final result */
@@ -106,9 +107,9 @@ static int codepoint (lua_State *L) {
   luaL_argcheck(L, posi >= 1, 2, "out of range");
   luaL_argcheck(L, pose <= (lua_Integer)len, 3, "out of range");
   if (posi > pose) return 0;  /* empty interval; return no values */
-  n = (int)(pose -  posi + 1);
-  if (posi + n <= pose)  /* (lua_Integer -> int) overflow? */
+  if (pose - posi >= INT_MAX)  /* (lua_Integer -> int) overflow? */
     return luaL_error(L, "string slice too long");
+  n = (int)(pose -  posi) + 1;
   luaL_checkstack(L, n, "string slice too long");
   n = 0;
   se = s + pose;
@@ -234,7 +235,7 @@ static int iter_codes (lua_State *L) {
 #define UTF8PATT        "[\0-\x7F\xC2-\xF4][\x80-\xBF]*"
 
 
-static struct luaL_Reg funcs[] = {
+static const luaL_Reg funcs[] = {
   {"offset", byteoffset},
   {"codepoint", codepoint},
   {"char", utfchar},
@@ -248,7 +249,7 @@ static struct luaL_Reg funcs[] = {
 
 LUAMOD_API int luaopen_utf8 (lua_State *L) {
   luaL_newlib(L, funcs);
-  lua_pushliteral(L, UTF8PATT);
+  lua_pushlstring(L, UTF8PATT, sizeof(UTF8PATT)/sizeof(char) - 1);
   lua_setfield(L, -2, "charpattern");
   return 1;
 }