1 files changed, 265 insertions, 238 deletions

diff --git a/src/lib/lstrlib.c b/src/lib/lstrlib.c
index b47e21d3..8f286982 100644
--- a/src/lib/lstrlib.c
+++ b/src/lib/lstrlib.c
@@ -1,112 +1,111 @@
 /*
-** $Id: lstrlib.c,v 1.32 1999/06/17 17:04:03 roberto Exp $
-** Standard library for strings and pattern-matching
+** $Id: lstrlib.c,v 1.56 2000/10/27 16:15:53 roberto Exp $
+** Standard library for string operations and pattern-matching
 ** See Copyright Notice in lua.h
 */
 
 
 #include <ctype.h>
+#include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
-#include "lauxlib.h"
 #include "lua.h"
-#include "lualib.h"
-
-
-
-static void addnchar (char *s, int n)
-{
-  char *b = luaL_openspace(n);
-  memcpy(b, s, n);
-  luaL_addsize(n);
-}
 
+#include "lauxlib.h"
+#include "lualib.h"
 
-static void str_len (void)
-{
-  long l;
-  luaL_check_lstr(1, &l);
-  lua_pushnumber(l);
-}
 
 
-static void closeandpush (void) {
-  lua_pushlstring(luaL_buffer(), luaL_getsize());
+static int str_len (lua_State *L) {
+  size_t l;
+  luaL_check_lstr(L, 1, &l);
+  lua_pushnumber(L, l);
+  return 1;
 }
 
 
-static long posrelat (long pos, long len) {
+static long posrelat (long pos, size_t len) {
   /* relative string position: negative means back from end */
-  return (pos>=0) ? pos : len+pos+1;
+  return (pos>=0) ? pos : (long)len+pos+1;
 }
 
 
-static void str_sub (void) {
-  long l;
-  char *s = luaL_check_lstr(1, &l);
-  long start = posrelat(luaL_check_long(2), l);
-  long end = posrelat(luaL_opt_long(3, -1), l);
+static int str_sub (lua_State *L) {
+  size_t l;
+  const char *s = luaL_check_lstr(L, 1, &l);
+  long start = posrelat(luaL_check_long(L, 2), l);
+  long end = posrelat(luaL_opt_long(L, 3, -1), l);
   if (start < 1) start = 1;
-  if (end > l) end = l;
+  if (end > (long)l) end = l;
   if (start <= end)
-    lua_pushlstring(s+start-1, end-start+1);
-  else lua_pushstring("");
+    lua_pushlstring(L, s+start-1, end-start+1);
+  else lua_pushstring(L, "");
+  return 1;
 }
 
 
-static void str_lower (void) {
-  long l;
-  int i;
-  char *s = luaL_check_lstr(1, &l);
-  luaL_resetbuffer();
+static int str_lower (lua_State *L) {
+  size_t l;
+  size_t i;
+  luaL_Buffer b;
+  const char *s = luaL_check_lstr(L, 1, &l);
+  luaL_buffinit(L, &b);
   for (i=0; i<l; i++)
-    luaL_addchar(tolower((unsigned char)(s[i])));
-  closeandpush();
+    luaL_putchar(&b, tolower((unsigned char)(s[i])));
+  luaL_pushresult(&b);
+  return 1;
 }
 
 
-static void str_upper (void) {
-  long l;
-  int i;
-  char *s = luaL_check_lstr(1, &l);
-  luaL_resetbuffer();
+static int str_upper (lua_State *L) {
+  size_t l;
+  size_t i;
+  luaL_Buffer b;
+  const char *s = luaL_check_lstr(L, 1, &l);
+  luaL_buffinit(L, &b);
   for (i=0; i<l; i++)
-    luaL_addchar(toupper((unsigned char)(s[i])));
-  closeandpush();
+    luaL_putchar(&b, toupper((unsigned char)(s[i])));
+  luaL_pushresult(&b);
+  return 1;
 }
 
-static void str_rep (void)
-{
-  long l;
-  char *s = luaL_check_lstr(1, &l);
-  int n = luaL_check_int(2);
-  luaL_resetbuffer();
+static int str_rep (lua_State *L) {
+  size_t l;
+  luaL_Buffer b;
+  const char *s = luaL_check_lstr(L, 1, &l);
+  int n = luaL_check_int(L, 2);
+  luaL_buffinit(L, &b);
   while (n-- > 0)
-    addnchar(s, l);
-  closeandpush();
+    luaL_addlstring(&b, s, l);
+  luaL_pushresult(&b);
+  return 1;
 }
 
 
-static void str_byte (void) {
-  long l;
-  char *s = luaL_check_lstr(1, &l);
-  long pos = posrelat(luaL_opt_long(2, 1), l);
-  luaL_arg_check(0<pos && pos<=l, 2,  "out of range");
-  lua_pushnumber((unsigned char)s[pos-1]);
+static int str_byte (lua_State *L) {
+  size_t l;
+  const char *s = luaL_check_lstr(L, 1, &l);
+  long pos = posrelat(luaL_opt_long(L, 2, 1), l);
+  luaL_arg_check(L, 0<pos && (size_t)pos<=l, 2,  "out of range");
+  lua_pushnumber(L, (unsigned char)s[pos-1]);
+  return 1;
 }
 
 
-static void str_char (void) {
-  int i = 0;
-  luaL_resetbuffer();
-  while (lua_getparam(++i) != LUA_NOOBJECT) {
-    double c = luaL_check_number(i);
-    luaL_arg_check((unsigned char)c == c, i, "invalid value");
-    luaL_addchar((unsigned char)c);
+static int str_char (lua_State *L) {
+  int n = lua_gettop(L);  /* number of arguments */
+  int i;
+  luaL_Buffer b;
+  luaL_buffinit(L, &b);
+  for (i=1; i<=n; i++) {
+    int c = luaL_check_int(L, i);
+    luaL_arg_check(L, (unsigned char)c == c, i, "invalid value");
+    luaL_putchar(&b, (unsigned char)c);
   }
-  closeandpush();
+  luaL_pushresult(&b);
+  return 1;
 }
 
 
@@ -117,63 +116,53 @@ static void str_char (void) {
 ** =======================================================
 */
 
-#ifndef MAX_CAPT
-#define MAX_CAPT 32  /* arbitrary limit */
+#ifndef MAX_CAPTURES
+#define MAX_CAPTURES 32  /* arbitrary limit */
 #endif
 
 
 struct Capture {
-  char *src_end;  /* end ('\0') of source string */
+  const char *src_end;  /* end ('\0') of source string */
   int level;  /* total number of captures (finished or unfinished) */
   struct {
-    char *init;
-    int len;  /* -1 signals unfinished capture */
-  } capture[MAX_CAPT];
+    const char *init;
+    long len;  /* -1 signals unfinished capture */
+  } capture[MAX_CAPTURES];
 };
 
 
-#define ESC	'%'
-#define SPECIALS  "^$*+?.([%-"
+#define ESC		'%'
+#define SPECIALS	"^$*+?.([%-"
 
 
-static void push_captures (struct Capture *cap) {
-  int i;
-  for (i=0; i<cap->level; i++) {
-    int l = cap->capture[i].len;
-    if (l == -1) lua_error("unfinished capture");
-    lua_pushlstring(cap->capture[i].init, l);
-  }
-}
-
-
-static int check_cap (int l, struct Capture *cap) {
+static int check_capture (lua_State *L, int l, struct Capture *cap) {
   l -= '1';
   if (!(0 <= l && l < cap->level && cap->capture[l].len != -1))
-    lua_error("invalid capture index");
+    lua_error(L, "invalid capture index");
   return l;
 }
 
 
-static int capture_to_close (struct Capture *cap) {
+static int capture_to_close (lua_State *L, struct Capture *cap) {
   int level = cap->level;
   for (level--; level>=0; level--)
     if (cap->capture[level].len == -1) return level;
-  lua_error("invalid pattern capture");
+  lua_error(L, "invalid pattern capture");
   return 0;  /* to avoid warnings */
 }
 
 
-char *luaI_classend (char *p) {
+const char *luaI_classend (lua_State *L, const char *p) {
   switch (*p++) {
     case ESC:
-      if (*p == '\0')
-        luaL_verror("incorrect pattern (ends with `%c')", ESC);
+      if (*p == '\0') lua_error(L, "malformed pattern (ends with `%')");
       return p+1;
     case '[':
       if (*p == '^') p++;
-      if (*p == ']') p++;
-      p = strchr(p, ']');
-      if (!p) lua_error("incorrect pattern (missing `]')");
+      do {  /* look for a ']' */
+        if (*p == '\0') lua_error(L, "malformed pattern (missing `]')");
+        if (*(p++) == ESC && *p != '\0') p++;  /* skip escapes (e.g. '%]') */
+      } while (*p != ']');
       return p+1;
     default:
       return p;
@@ -181,7 +170,7 @@ char *luaI_classend (char *p) {
 }
 
 
-static int matchclass (int c, int cl) {
+static int match_class (int c, int cl) {
   int res;
   switch (tolower(cl)) {
     case 'a' : res = isalpha(c); break;
@@ -201,36 +190,36 @@ static int matchclass (int c, int cl) {
 
 
 
-static int matchbracketclass (int c, char *p, char *end) {
+static int matchbracketclass (int c, const char *p, const char *endclass) {
   int sig = 1;
   if (*(p+1) == '^') {
     sig = 0;
     p++;  /* skip the '^' */
   }
-  while (++p < end) {
+  while (++p < endclass) {
     if (*p == ESC) {
       p++;
-      if ((p < end) && matchclass(c, (unsigned char)*p))
+      if (match_class(c, (unsigned char)*p))
         return sig;
     }
-    else if ((*(p+1) == '-') && (p+2 < end)) {
+    else if ((*(p+1) == '-') && (p+2 < endclass)) {
       p+=2;
       if ((int)(unsigned char)*(p-2) <= c && c <= (int)(unsigned char)*p)
         return sig;
     }
-    else if ((unsigned char)*p == c) return sig;
+    else if ((int)(unsigned char)*p == c) return sig;
   }
   return !sig;
 }
 
 
 
-int luaI_singlematch (int c, char *p, char *ep) {
+int luaI_singlematch (int c, const char *p, const char *ep) {
   switch (*p) {
     case '.':  /* matches any char */
       return 1;
     case ESC:
-      return matchclass(c, (unsigned char)*(p+1));
+      return match_class(c, (unsigned char)*(p+1));
     case '[':
       return matchbracketclass(c, p, ep-1);
     default:
@@ -239,12 +228,14 @@ int luaI_singlematch (int c, char *p, char *ep) {
 }
 
 
-static char *match (char *s, char *p, struct Capture *cap);
+static const char *match (lua_State *L, const char *s, const char *p,
+                          struct Capture *cap);
 
 
-static char *matchbalance (char *s, char *p, struct Capture *cap) {
+static const char *matchbalance (lua_State *L, const char *s, const char *p,
+                                 struct Capture *cap) {
   if (*p == 0 || *(p+1) == 0)
-    lua_error("unbalanced pattern");
+    lua_error(L, "unbalanced pattern");
   if (*s != *p) return NULL;
   else {
     int b = *p;
@@ -261,13 +252,14 @@ static char *matchbalance (char *s, char *p, struct Capture *cap) {
 }
 
 
-static char *max_expand (char *s, char *p, char *ep, struct Capture *cap) {
-  int i = 0;  /* counts maximum expand for item */
+static const char *max_expand (lua_State *L, const char *s, const char *p,
+                               const char *ep, struct Capture *cap) {
+  long i = 0;  /* counts maximum expand for item */
   while ((s+i)<cap->src_end && luaI_singlematch((unsigned char)*(s+i), p, ep))
     i++;
-  /* keeps trying to match mith the maximum repetitions */
+  /* keeps trying to match with the maximum repetitions */
   while (i>=0) {
-    char *res = match((s+i), ep+1, cap);
+    const char *res = match(L, (s+i), ep+1, cap);
     if (res) return res;
     i--;  /* else didn't match; reduce 1 repetition to try again */
   }
@@ -275,9 +267,10 @@ static char *max_expand (char *s, char *p, char *ep, struct Capture *cap) {
 }
 
 
-static char *min_expand (char *s, char *p, char *ep, struct Capture *cap) {
+static const char *min_expand (lua_State *L, const char *s, const char *p,
+                               const char *ep, struct Capture *cap) {
   for (;;) {
-    char *res = match(s, ep+1, cap);
+    const char *res = match(L, s, ep+1, cap);
     if (res != NULL)
       return res;
     else if (s<cap->src_end && luaI_singlematch((unsigned char)*s, p, ep))
@@ -287,56 +280,60 @@ static char *min_expand (char *s, char *p, char *ep, struct Capture *cap) {
 }
 
 
-static char *start_capt (char *s, char *p, struct Capture *cap) {
-  char *res;
+static const char *start_capture (lua_State *L, const char *s, const char *p,
+                                  struct Capture *cap) {
+  const char *res;
   int level = cap->level;
-  if (level >= MAX_CAPT) lua_error("too many captures");
+  if (level >= MAX_CAPTURES) lua_error(L, "too many captures");
   cap->capture[level].init = s;
   cap->capture[level].len = -1;
   cap->level = level+1;
-  if ((res=match(s, p+1, cap)) == NULL)  /* match failed? */
+  if ((res=match(L, s, p+1, cap)) == NULL)  /* match failed? */
     cap->level--;  /* undo capture */
   return res;
 }
 
 
-static char *end_capt (char *s, char *p, struct Capture *cap) {
-  int l = capture_to_close(cap);
-  char *res;
+static const char *end_capture (lua_State *L, const char *s, const char *p,
+                                struct Capture *cap) {
+  int l = capture_to_close(L, cap);
+  const char *res;
   cap->capture[l].len = s - cap->capture[l].init;  /* close capture */
-  if ((res = match(s, p+1, cap)) == NULL)  /* match failed? */
+  if ((res = match(L, s, p+1, cap)) == NULL)  /* match failed? */
     cap->capture[l].len = -1;  /* undo capture */
   return res;
 }
 
 
-static char *match_capture (char *s, int level, struct Capture *cap) {
-  int l = check_cap(level, cap);
-  int len = cap->capture[l].len;
-  if (cap->src_end-s >= len &&
+static const char *match_capture (lua_State *L, const char *s, int level,
+                                  struct Capture *cap) {
+  int l = check_capture(L, level, cap);
+  size_t len = cap->capture[l].len;
+  if ((size_t)(cap->src_end-s) >= len &&
       memcmp(cap->capture[l].init, s, len) == 0)
     return s+len;
   else return NULL;
 }
 
 
-static char *match (char *s, char *p, struct Capture *cap) {
+static const char *match (lua_State *L, const char *s, const char *p,
+                          struct Capture *cap) {
   init: /* using goto's to optimize tail recursion */
   switch (*p) {
     case '(':  /* start capture */
-      return start_capt(s, p, cap);
+      return start_capture(L, s, p, cap);
     case ')':  /* end capture */
-      return end_capt(s, p, cap);
+      return end_capture(L, s, p, cap);
     case ESC:  /* may be %[0-9] or %b */
       if (isdigit((unsigned char)(*(p+1)))) {  /* capture? */
-        s = match_capture(s, *(p+1), cap);
+        s = match_capture(L, s, *(p+1), cap);
         if (s == NULL) return NULL;
-        p+=2; goto init;  /* else return match(p+2, s, cap) */
+        p+=2; goto init;  /* else return match(L, s, p+2, cap) */
       }
       else if (*(p+1) == 'b') {  /* balanced string? */
-        s = matchbalance(s, p+2, cap);
+        s = matchbalance(L, s, p+2, cap);
         if (s == NULL) return NULL;
-        p+=4; goto init;  /* else return match(p+4, s, cap); */
+        p+=4; goto init;  /* else return match(L, s, p+4, cap); */
       }
       else goto dflt;  /* case default */
     case '\0':  /* end of pattern */
@@ -346,178 +343,208 @@ static char *match (char *s, char *p, struct Capture *cap) {
         return (s == cap->src_end) ? s : NULL;  /* check end of string */
       else goto dflt;
     default: dflt: {  /* it is a pattern item */
-      char *ep = luaI_classend(p);  /* points to what is next */
+      const char *ep = luaI_classend(L, p);  /* points to what is next */
       int m = s<cap->src_end && luaI_singlematch((unsigned char)*s, p, ep);
       switch (*ep) {
         case '?': {  /* optional */
-          char *res;
-          if (m && ((res=match(s+1, ep+1, cap)) != NULL))
+          const char *res;
+          if (m && ((res=match(L, s+1, ep+1, cap)) != NULL))
             return res;
-          p=ep+1; goto init;  /* else return match(s, ep+1, cap); */
+          p=ep+1; goto init;  /* else return match(L, s, ep+1, cap); */
         }
         case '*':  /* 0 or more repetitions */
-          return max_expand(s, p, ep, cap);
+          return max_expand(L, s, p, ep, cap);
         case '+':  /* 1 or more repetitions */
-          return (m ? max_expand(s+1, p, ep, cap) : NULL);
+          return (m ? max_expand(L, s+1, p, ep, cap) : NULL);
         case '-':  /* 0 or more repetitions (minimum) */
-          return min_expand(s, p, ep, cap);
+          return min_expand(L, s, p, ep, cap);
         default:
           if (!m) return NULL;
-          s++; p=ep; goto init;  /* else return match(s+1, ep, cap); */
+          s++; p=ep; goto init;  /* else return match(L, s+1, ep, cap); */
+      }
+    }
+  }
+}
+
+
+
+static const char *lmemfind (const char *s1, size_t l1,
+                             const char *s2, size_t l2) {
+  if (l2 == 0) return s1;  /* empty strings are everywhere */
+  else if (l2 > l1) return NULL;  /* avoids a negative `l1' */
+  else {
+    const char *init;  /* to search for a `*s2' inside `s1' */
+    l2--;  /* 1st char will be checked by `memchr' */
+    l1 = l1-l2;  /* `s2' cannot be found after that */
+    while (l1 > 0 && (init = (const char *)memchr(s1, *s2, l1)) != NULL) {
+      init++;   /* 1st char is already checked */
+      if (memcmp(init, s2+1, l2) == 0)
+        return init-1;
+      else {  /* correct `l1' and `s1' to try again */
+        l1 -= init-s1;
+        s1 = init;
       }
     }
+    return NULL;  /* not found */
   }
 }
 
 
-static void str_find (void) {
-  long l;
-  char *s = luaL_check_lstr(1, &l);
-  char *p = luaL_check_string(2);
-  long init = posrelat(luaL_opt_long(3, 1), l) - 1;
+static int push_captures (lua_State *L, struct Capture *cap) {
+  int i;
+  luaL_checkstack(L, cap->level, "too many captures");
+  for (i=0; i<cap->level; i++) {
+    int l = cap->capture[i].len;
+    if (l == -1) lua_error(L, "unfinished capture");
+    lua_pushlstring(L, cap->capture[i].init, l);
+  }
+  return cap->level;  /* number of strings pushed */
+}
+
+
+static int str_find (lua_State *L) {
+  size_t l1, l2;
+  const char *s = luaL_check_lstr(L, 1, &l1);
+  const char *p = luaL_check_lstr(L, 2, &l2);
+  long init = posrelat(luaL_opt_long(L, 3, 1), l1) - 1;
   struct Capture cap;
-  luaL_arg_check(0 <= init && init <= l, 3, "out of range");
-  if (lua_getparam(4) != LUA_NOOBJECT ||
-      strpbrk(p, SPECIALS) == NULL) {  /* no special characters? */
-    char *s2 = strstr(s+init, p);
+  luaL_arg_check(L, 0 <= init && (size_t)init <= l1, 3, "out of range");
+  if (lua_gettop(L) > 3 ||  /* extra argument? */
+      strpbrk(p, SPECIALS) == NULL) {  /* or no special characters? */
+    const char *s2 = lmemfind(s+init, l1-init, p, l2);
     if (s2) {
-      lua_pushnumber(s2-s+1);
-      lua_pushnumber(s2-s+strlen(p));
-      return;
+      lua_pushnumber(L, s2-s+1);
+      lua_pushnumber(L, s2-s+l2);
+      return 2;
     }
   }
   else {
     int anchor = (*p == '^') ? (p++, 1) : 0;
-    char *s1=s+init;
-    cap.src_end = s+l;
+    const char *s1=s+init;
+    cap.src_end = s+l1;
     do {
-      char *res;
+      const char *res;
       cap.level = 0;
-      if ((res=match(s1, p, &cap)) != NULL) {
-        lua_pushnumber(s1-s+1);  /* start */
-        lua_pushnumber(res-s);   /* end */
-        push_captures(&cap);
-        return;
+      if ((res=match(L, s1, p, &cap)) != NULL) {
+        lua_pushnumber(L, s1-s+1);  /* start */
+        lua_pushnumber(L, res-s);   /* end */
+        return push_captures(L, &cap) + 2;
       }
     } while (s1++<cap.src_end && !anchor);
   }
-  lua_pushnil();  /* if arrives here, it didn't find */
+  lua_pushnil(L);  /* not found */
+  return 1;
 }
 
 
-static void add_s (lua_Object newp, struct Capture *cap) {
-  if (lua_isstring(newp)) {
-    char *news = lua_getstring(newp);
-    int l = lua_strlen(newp);
-    int i;
+static void add_s (lua_State *L, luaL_Buffer *b, struct Capture *cap) {
+  if (lua_isstring(L, 3)) {
+    const char *news = lua_tostring(L, 3);
+    size_t l = lua_strlen(L, 3);
+    size_t i;
     for (i=0; i<l; i++) {
       if (news[i] != ESC)
-        luaL_addchar(news[i]);
+        luaL_putchar(b, news[i]);
       else {
         i++;  /* skip ESC */
         if (!isdigit((unsigned char)news[i]))
-          luaL_addchar(news[i]);
+          luaL_putchar(b, news[i]);
         else {
-          int level = check_cap(news[i], cap);
-          addnchar(cap->capture[level].init, cap->capture[level].len);
+          int level = check_capture(L, news[i], cap);
+          luaL_addlstring(b, cap->capture[level].init, cap->capture[level].len);
         }
       }
     }
   }
   else {  /* is a function */
-    lua_Object res;
-    int status;
-    int oldbuff;
-    lua_beginblock();
-    push_captures(cap);
-    /* function may use buffer, so save it and create a new one */
-    oldbuff = luaL_newbuffer(0);
-    status = lua_callfunction(newp);
-    /* restore old buffer */
-    luaL_oldbuffer(oldbuff);
-    if (status != 0) {
-      lua_endblock();
-      lua_error(NULL);
-    }
-    res = lua_getresult(1);
-    if (lua_isstring(res))
-      addnchar(lua_getstring(res), lua_strlen(res));
-    lua_endblock();
+    int n;
+    lua_pushvalue(L, 3);
+    n = push_captures(L, cap);
+    lua_rawcall(L, n, 1);
+    if (lua_isstring(L, -1))
+      luaL_addvalue(b);  /* add return to accumulated result */
+    else
+      lua_pop(L, 1);  /* function result is not a string: pop it */
   }
 }
 
 
-static void str_gsub (void) {
-  long srcl;
-  char *src = luaL_check_lstr(1, &srcl);
-  char *p = luaL_check_string(2);
-  lua_Object newp = lua_getparam(3);
-  int max_s = luaL_opt_int(4, srcl+1);
+static int str_gsub (lua_State *L) {
+  size_t srcl;
+  const char *src = luaL_check_lstr(L, 1, &srcl);
+  const char *p = luaL_check_string(L, 2);
+  int max_s = luaL_opt_int(L, 4, srcl+1);
   int anchor = (*p == '^') ? (p++, 1) : 0;
   int n = 0;
   struct Capture cap;
-  luaL_arg_check(lua_isstring(newp) || lua_isfunction(newp), 3,
-                 "string or function expected");
-  luaL_resetbuffer();
+  luaL_Buffer b;
+  luaL_arg_check(L,
+    lua_gettop(L) >= 3 && (lua_isstring(L, 3) || lua_isfunction(L, 3)),
+    3, "string or function expected");
+  luaL_buffinit(L, &b);
   cap.src_end = src+srcl;
   while (n < max_s) {
-    char *e;
+    const char *e;
     cap.level = 0;
-    e = match(src, p, &cap);
+    e = match(L, src, p, &cap);
     if (e) {
       n++;
-      add_s(newp, &cap);
+      add_s(L, &b, &cap);
     }
     if (e && e>src) /* non empty match? */
       src = e;  /* skip it */
     else if (src < cap.src_end)
-      luaL_addchar(*src++);
+      luaL_putchar(&b, *src++);
     else break;
     if (anchor) break;
   }
-  addnchar(src, cap.src_end-src);
-  closeandpush();
-  lua_pushnumber(n);  /* number of substitutions */
+  luaL_addlstring(&b, src, cap.src_end-src);
+  luaL_pushresult(&b);
+  lua_pushnumber(L, n);  /* number of substitutions */
+  return 2;
 }
 
 /* }====================================================== */
 
 
-static void luaI_addquoted (int arg) {
-  long l;
-  char *s = luaL_check_lstr(arg, &l);
-  luaL_addchar('"');
+static void luaI_addquoted (lua_State *L, luaL_Buffer *b, int arg) {
+  size_t l;
+  const char *s = luaL_check_lstr(L, arg, &l);
+  luaL_putchar(b, '"');
   while (l--) {
     switch (*s) {
       case '"':  case '\\':  case '\n':
-        luaL_addchar('\\');
-        luaL_addchar(*s);
+        luaL_putchar(b, '\\');
+        luaL_putchar(b, *s);
         break;
-      case '\0': addnchar("\\000", 4); break;
-      default: luaL_addchar(*s);
+      case '\0': luaL_addlstring(b, "\\000", 4); break;
+      default: luaL_putchar(b, *s);
     }
     s++;
   }
-  luaL_addchar('"');
+  luaL_putchar(b, '"');
 }
 
+/* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */
+#define MAX_ITEM	512
 /* maximum size of each format specification (such as '%-099.99d') */
-#define MAX_FORMAT 20  /* arbitrary limit */
+#define MAX_FORMAT	20
 
-static void str_format (void) {
+static int str_format (lua_State *L) {
   int arg = 1;
-  char *strfrmt = luaL_check_string(arg);
-  luaL_resetbuffer();
+  const char *strfrmt = luaL_check_string(L, arg);
+  luaL_Buffer b;
+  luaL_buffinit(L, &b);
   while (*strfrmt) {
     if (*strfrmt != '%')
-      luaL_addchar(*strfrmt++);
+      luaL_putchar(&b, *strfrmt++);
     else if (*++strfrmt == '%')
-      luaL_addchar(*strfrmt++);  /* %% */
+      luaL_putchar(&b, *strfrmt++);  /* %% */
     else { /* format item */
       struct Capture cap;
       char form[MAX_FORMAT];  /* to store the format ('%...') */
-      char *buff;  /* to store the formatted item */
-      char *initf = strfrmt;
+      char buff[MAX_ITEM];  /* to store the formatted item */
+      const char *initf = strfrmt;
       form[0] = '%';
       if (isdigit((unsigned char)*initf) && *(initf+1) == '$') {
         arg = *initf - '0';
@@ -526,33 +553,33 @@ static void str_format (void) {
       arg++;
       cap.src_end = strfrmt+strlen(strfrmt)+1;
       cap.level = 0;
-      strfrmt = match(initf, "[-+ #0]*(%d*)%.?(%d*)", &cap);
+      strfrmt = match(L, initf, "[-+ #0]*(%d*)%.?(%d*)", &cap);
       if (cap.capture[0].len > 2 || cap.capture[1].len > 2 ||  /* < 100? */
           strfrmt-initf > MAX_FORMAT-2)
-        lua_error("invalid format (width or precision too long)");
+        lua_error(L, "invalid format (width or precision too long)");
       strncpy(form+1, initf, strfrmt-initf+1); /* +1 to include conversion */
       form[strfrmt-initf+2] = 0;
-      buff = luaL_openspace(512);  /* 512 > size of format('%99.99f', -1e308) */
       switch (*strfrmt++) {
         case 'c':  case 'd':  case 'i':
-          sprintf(buff, form, luaL_check_int(arg));
+          sprintf(buff, form, luaL_check_int(L, arg));
           break;
         case 'o':  case 'u':  case 'x':  case 'X':
-          sprintf(buff, form, (unsigned int)luaL_check_number(arg));
+          sprintf(buff, form, (unsigned int)luaL_check_number(L, arg));
           break;
         case 'e':  case 'E': case 'f': case 'g': case 'G':
-          sprintf(buff, form, luaL_check_number(arg));
+          sprintf(buff, form, luaL_check_number(L, arg));
           break;
         case 'q':
-          luaI_addquoted(arg);
+          luaI_addquoted(L, &b, arg);
           continue;  /* skip the "addsize" at the end */
         case 's': {
-          long l;
-          char *s = luaL_check_lstr(arg, &l);
+          size_t l;
+          const char *s = luaL_check_lstr(L, arg, &l);
           if (cap.capture[1].len == 0 && l >= 100) {
-            /* no precision and string is too big to be formatted;
+            /* no precision and string is too long to be formatted;
                keep original string */
-            addnchar(s, l);
+            lua_pushvalue(L, arg);
+            luaL_addvalue(&b);
             continue;  /* skip the "addsize" at the end */
           }
           else {
@@ -561,16 +588,17 @@ static void str_format (void) {
           }
         }
         default:  /* also treat cases 'pnLlh' */
-          lua_error("invalid option in `format'");
+          lua_error(L, "invalid option in `format'");
       }
-      luaL_addsize(strlen(buff));
+      luaL_addlstring(&b, buff, strlen(buff));
     }
   }
-  closeandpush();  /* push the result */
+  luaL_pushresult(&b);
+  return 1;
 }
 
 
-static struct luaL_reg strlib[] = {
+static const struct luaL_reg strlib[] = {
 {"strlen", str_len},
 {"strsub", str_sub},
 {"strlower", str_lower},
@@ -588,7 +616,6 @@ static struct luaL_reg strlib[] = {
 /*
 ** Open string library
 */
-void strlib_open (void)
-{
-  luaL_openlib(strlib, (sizeof(strlib)/sizeof(strlib[0])));
+LUALIB_API void lua_strlibopen (lua_State *L) {
+  luaL_openl(L, strlib);
 }