/*

 ** $Id: lstrlib.c,v 1.132.1.4 2008/07/11 17:27:21 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>

 

 #define lstrlib_c

 #define LUA_LIB

 

 #include "lua.h"

 

 #include "lauxlib.h"

 #include "lualib.h"

 

 

 /* macro to `unsign' a character */

 #define uchar(c)        ((unsigned char)(c))

 

 

 

 static int str_len (lua_State *L) {

   size_t l;

   luaL_checklstring(L, 1, &l);

   lua_pushinteger(L, l);

   return 1;

 }

 

 

 static ptrdiff_t posrelat (ptrdiff_t pos, size_t len) {

   /* relative string position: negative means back from end */

   if (pos < 0) pos += (ptrdiff_t)len + 1;

   return (pos >= 0) ? pos : 0;

 }

 

 

 static int str_sub (lua_State *L) {

   size_t l;

   const char *s = luaL_checklstring(L, 1, &l);

   ptrdiff_t start = posrelat(luaL_checkinteger(L, 2), l);

   ptrdiff_t end = posrelat(luaL_optinteger(L, 3, -1), l);

   if (start < 1) start = 1;

   if (end > (ptrdiff_t)l) end = (ptrdiff_t)l;

   if (start <= end)

     lua_pushlstring(L, s+start-1, end-start+1);

   else lua_pushliteral(L, "");

   return 1;

 }

 

 

 static int str_reverse (lua_State *L) {

   size_t l;

   luaL_Buffer b;

   const char *s = luaL_checklstring(L, 1, &l);

   luaL_buffinit(L, &b);

   while (l--) luaL_addchar(&b, s[l]);

   luaL_pushresult(&b);

   return 1;

 }

 

 

 static int str_lower (lua_State *L) {

   size_t l;

   size_t i;

   luaL_Buffer b;

   const char *s = luaL_checklstring(L, 1, &l);

   luaL_buffinit(L, &b);

   for (i=0; i<l; i++)

     luaL_addchar(&b, tolower(uchar(s[i])));

   luaL_pushresult(&b);

   return 1;

 }

 

 

 static int str_upper (lua_State *L) {

   size_t l;

   size_t i;

   luaL_Buffer b;

   const char *s = luaL_checklstring(L, 1, &l);

   luaL_buffinit(L, &b);

   for (i=0; i<l; i++)

     luaL_addchar(&b, toupper(uchar(s[i])));

   luaL_pushresult(&b);

   return 1;

 }

 

 static int str_rep (lua_State *L) {

   size_t l;

   luaL_Buffer b;

   const char *s = luaL_checklstring(L, 1, &l);

   int n = luaL_checkint(L, 2);

   luaL_buffinit(L, &b);

   while (n-- > 0)

     luaL_addlstring(&b, s, l);

   luaL_pushresult(&b);

   return 1;

 }

 

 

 static int str_byte (lua_State *L) {

   size_t l;

   const char *s = luaL_checklstring(L, 1, &l);

   ptrdiff_t posi = posrelat(luaL_optinteger(L, 2, 1), l);

   ptrdiff_t pose = posrelat(luaL_optinteger(L, 3, posi), l);

   int n, i;

   if (posi <= 0) posi = 1;

   if ((size_t)pose > l) pose = l;

   if (posi > pose) return 0;  /* empty interval; return no values */

   n = (int)(pose -  posi + 1);

   if (posi + n <= pose)  /* overflow? */

     luaL_error(L, "string slice too long");

   luaL_checkstack(L, n, "string slice too long");

   for (i=0; i<n; i++)

     lua_pushinteger(L, uchar(s[posi+i-1]));

   return n;

 }

 

 

 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_checkint(L, i);

     luaL_argcheck(L, uchar(c) == c, i, "invalid value");

     luaL_addchar(&b, uchar(c));

   }

   luaL_pushresult(&b);

   return 1;

 }

 

 

 static int writer (lua_State *L, const void* b, size_t size, void* B) {

   (void)L;

   luaL_addlstring((luaL_Buffer*) B, (const char *)b, size);

   return 0;

 }

 

 

 static int str_dump (lua_State *L) {

   luaL_Buffer b;

   luaL_checktype(L, 1, LUA_TFUNCTION);

   lua_settop(L, 1);

   luaL_buffinit(L,&b);

   if (lua_dump(L, writer, &b) != 0)

     luaL_error(L, "unable to dump given function");

   luaL_pushresult(&b);

   return 1;

 }

 

 

 

 /*

 ** {======================================================

 ** PATTERN MATCHING

 ** =======================================================

 */

 

 

 #define CAP_UNFINISHED	(-1)

 #define CAP_POSITION	(-2)

 

 typedef struct MatchState {

   const char *src_init;  /* init of source string */

   const char *src_end;  /* end (`\0') of source string */

   lua_State *L;

   int level;  /* total number of captures (finished or unfinished) */

   struct {

     const char *init;

     ptrdiff_t len;

   } capture[LUA_MAXCAPTURES];

 } MatchState;

 

 

 #define L_ESC		'%'

 #define SPECIALS	"^$*+?.([%-"

 

 

 static int check_capture (MatchState *ms, int l) {

   l -= '1';

   if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED)

     return luaL_error(ms->L, "invalid capture index");

   return l;

 }

 

 

 static int capture_to_close (MatchState *ms) {

   int level = ms->level;

   for (level--; level>=0; level--)

     if (ms->capture[level].len == CAP_UNFINISHED) return level;

   return luaL_error(ms->L, "invalid pattern capture");

 }

 

 

 static const char *classend (MatchState *ms, const char *p) {

   switch (*p++) {

     case L_ESC: {

       if (*p == '\0')

         luaL_error(ms->L, "malformed pattern (ends with " LUA_QL("%%") ")");

       return p+1;

     }

     case '[': {

       if (*p == '^') p++;

       do {  /* look for a `]' */

         if (*p == '\0')

           luaL_error(ms->L, "malformed pattern (missing " LUA_QL("]") ")");

         if (*(p++) == L_ESC && *p != '\0')

           p++;  /* skip escapes (e.g. `%]') */

       } while (*p != ']');

       return p+1;

     }

     default: {

       return p;

     }

   }

 }

 

 

 static int match_class (int c, int cl) {

   int res;

   switch (tolower(cl)) {

     case 'a' : res = isalpha(c); break;

     case 'c' : res = iscntrl(c); break;

     case 'd' : res = isdigit(c); break;

     case 'l' : res = islower(c); break;

     case 'p' : res = ispunct(c); break;

     case 's' : res = isspace(c); break;

     case 'u' : res = isupper(c); break;

     case 'w' : res = isalnum(c); break;

     case 'x' : res = isxdigit(c); break;

     case 'z' : res = (c == 0); break;

     default: return (cl == c);

   }

   return (islower(cl) ? res : !res);

 }

 

 

 static int matchbracketclass (int c, const char *p, const char *ec) {

   int sig = 1;

   if (*(p+1) == '^') {

     sig = 0;

     p++;  /* skip the `^' */

   }

   while (++p < ec) {

     if (*p == L_ESC) {

       p++;

       if (match_class(c, uchar(*p)))

         return sig;

     }

     else if ((*(p+1) == '-') && (p+2 < ec)) {

       p+=2;

       if (uchar(*(p-2)) <= c && c <= uchar(*p))

         return sig;

     }

     else if (uchar(*p) == c) return sig;

   }

   return !sig;

 }

 

 

 static int singlematch (int c, const char *p, const char *ep) {

   switch (*p) {

     case '.': return 1;  /* matches any char */

     case L_ESC: return match_class(c, uchar(*(p+1)));

     case '[': return matchbracketclass(c, p, ep-1);

     default:  return (uchar(*p) == c);

   }

 }

 

 

 static const char *match (MatchState *ms, const char *s, const char *p);

 

 

 static const char *matchbalance (MatchState *ms, const char *s,

                                    const char *p) {

   if (*p == 0 || *(p+1) == 0)

     luaL_error(ms->L, "unbalanced pattern");

   if (*s != *p) return NULL;

   else {

     int b = *p;

     int e = *(p+1);

     int cont = 1;

     while (++s < ms->src_end) {

       if (*s == e) {

         if (--cont == 0) return s+1;

       }

       else if (*s == b) cont++;

     }

   }

   return NULL;  /* string ends out of balance */

 }

 

 

 static const char *max_expand (MatchState *ms, const char *s,

                                  const char *p, const char *ep) {

   ptrdiff_t i = 0;  /* counts maximum expand for item */

   while ((s+i)<ms->src_end && singlematch(uchar(*(s+i)), p, ep))

     i++;

   /* keeps trying to match with the maximum repetitions */

   while (i>=0) {

     const char *res = match(ms, (s+i), ep+1);

     if (res) return res;

     i--;  /* else didn't match; reduce 1 repetition to try again */

   }

   return NULL;

 }

 

 

 static const char *min_expand (MatchState *ms, const char *s,

                                  const char *p, const char *ep) {

   for (;;) {

     const char *res = match(ms, s, ep+1);

     if (res != NULL)

       return res;

     else if (s<ms->src_end && singlematch(uchar(*s), p, ep))

       s++;  /* try with one more repetition */

     else return NULL;

   }

 }

 

 

 static const char *start_capture (MatchState *ms, const char *s,

                                     const char *p, int what) {

   const char *res;

   int level = ms->level;

   if (level >= LUA_MAXCAPTURES) luaL_error(ms->L, "too many captures");

   ms->capture[level].init = s;

   ms->capture[level].len = what;

   ms->level = level+1;

   if ((res=match(ms, s, p)) == NULL)  /* match failed? */

     ms->level--;  /* undo capture */

   return res;

 }

 

 

 static const char *end_capture (MatchState *ms, const char *s,

                                   const char *p) {

   int l = capture_to_close(ms);

   const char *res;

   ms->capture[l].len = s - ms->capture[l].init;  /* close capture */

   if ((res = match(ms, s, p)) == NULL)  /* match failed? */

     ms->capture[l].len = CAP_UNFINISHED;  /* undo capture */

   return res;

 }

 

 

 static const char *match_capture (MatchState *ms, const char *s, int l) {

   size_t len;

   l = check_capture(ms, l);

   len = ms->capture[l].len;

   if ((size_t)(ms->src_end-s) >= len &&

       memcmp(ms->capture[l].init, s, len) == 0)

     return s+len;

   else return NULL;

 }

 

 

 static const char *match (MatchState *ms, const char *s, const char *p) {

   init: /* using goto's to optimize tail recursion */

   switch (*p) {

     case '(': {  /* start capture */

       if (*(p+1) == ')')  /* position capture? */

         return start_capture(ms, s, p+2, CAP_POSITION);

       else

         return start_capture(ms, s, p+1, CAP_UNFINISHED);

     }

     case ')': {  /* end capture */

       return end_capture(ms, s, p+1);

     }

     case L_ESC: {

       switch (*(p+1)) {

         case 'b': {  /* balanced string? */

           s = matchbalance(ms, s, p+2);

           if (s == NULL) return NULL;

           p+=4; goto init;  /* else return match(ms, s, p+4); */

         }

         case 'f': {  /* frontier? */

           const char *ep; char previous;

           p += 2;

           if (*p != '[')

             luaL_error(ms->L, "missing " LUA_QL("[") " after "

                                LUA_QL("%%f") " in pattern");

           ep = classend(ms, p);  /* points to what is next */

           previous = (s == ms->src_init) ? '\0' : *(s-1);

           if (matchbracketclass(uchar(previous), p, ep-1) ||

              !matchbracketclass(uchar(*s), p, ep-1)) return NULL;

           p=ep; goto init;  /* else return match(ms, s, ep); */

         }

         default: {

           if (isdigit(uchar(*(p+1)))) {  /* capture results (%0-%9)? */

             s = match_capture(ms, s, uchar(*(p+1)));

             if (s == NULL) return NULL;

             p+=2; goto init;  /* else return match(ms, s, p+2) */

           }

           goto dflt;  /* case default */

         }

       }

     }

     case '\0': {  /* end of pattern */

       return s;  /* match succeeded */

     }

     case '$': {

       if (*(p+1) == '\0')  /* is the `$' the last char in pattern? */

         return (s == ms->src_end) ? s : NULL;  /* check end of string */

       else goto dflt;

     }

     default: dflt: {  /* it is a pattern item */

       const char *ep = classend(ms, p);  /* points to what is next */

       int m = s<ms->src_end && singlematch(uchar(*s), p, ep);

       switch (*ep) {

         case '?': {  /* optional */

           const char *res;

           if (m && ((res=match(ms, s+1, ep+1)) != NULL))

             return res;

           p=ep+1; goto init;  /* else return match(ms, s, ep+1); */

         }

         case '*': {  /* 0 or more repetitions */

           return max_expand(ms, s, p, ep);

         }

         case '+': {  /* 1 or more repetitions */

           return (m ? max_expand(ms, s+1, p, ep) : NULL);

         }

         case '-': {  /* 0 or more repetitions (minimum) */

           return min_expand(ms, s, p, ep);

         }

         default: {

           if (!m) return NULL;

           s++; p=ep; goto init;  /* else return match(ms, s+1, ep); */

         }

       }

     }

   }

 }

 

 

 

 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 push_onecapture (MatchState *ms, int i, const char *s,

                                                     const char *e) {

   if (i >= ms->level) {

     if (i == 0)  /* ms->level == 0, too */

       lua_pushlstring(ms->L, s, e - s);  /* add whole match */

     else

       luaL_error(ms->L, "invalid capture index");

   }

   else {

     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);

     else

       lua_pushlstring(ms->L, ms->capture[i].init, l);

   }

 }

 

 

 static int push_captures (MatchState *ms, const char *s, const char *e) {

   int i;

   int nlevels = (ms->level == 0 && s) ? 1 : ms->level;

   luaL_checkstack(ms->L, nlevels, "too many captures");

   for (i = 0; i < nlevels; i++)

     push_onecapture(ms, i, s, e);

   return nlevels;  /* number of strings pushed */

 }

 

 

 static int str_find_aux (lua_State *L, int find) {

   size_t l1, l2;

   const char *s = luaL_checklstring(L, 1, &l1);

   const char *p = luaL_checklstring(L, 2, &l2);

   ptrdiff_t init = posrelat(luaL_optinteger(L, 3, 1), l1) - 1;

   if (init < 0) init = 0;

   else if ((size_t)(init) > l1) init = (ptrdiff_t)l1;

   if (find && (lua_toboolean(L, 4) ||  /* explicit request? */

       strpbrk(p, SPECIALS) == NULL)) {  /* or no special characters? */

     /* do a plain search */

     const char *s2 = lmemfind(s+init, l1-init, p, l2);

     if (s2) {

       lua_pushinteger(L, s2-s+1);

       lua_pushinteger(L, s2-s+l2);

       return 2;

     }

   }

   else {

     MatchState ms;

     int anchor = (*p == '^') ? (p++, 1) : 0;

     const char *s1=s+init;

     ms.L = L;

     ms.src_init = s;

     ms.src_end = s+l1;

     do {

       const char *res;

       ms.level = 0;

       if ((res=match(&ms, s1, p)) != NULL) {

         if (find) {

           lua_pushinteger(L, s1-s+1);  /* start */

           lua_pushinteger(L, res-s);   /* end */

           return push_captures(&ms, NULL, 0) + 2;

         }

         else

           return push_captures(&ms, s1, res);

       }

     } while (s1++ < ms.src_end && !anchor);

   }

   lua_pushnil(L);  /* not found */

   return 1;

 }

 

 

 static int str_find (lua_State *L) {

   return str_find_aux(L, 1);

 }

 

 

 static int str_match (lua_State *L) {

   return str_find_aux(L, 0);

 }

 

 

 static int gmatch_aux (lua_State *L) {

   MatchState ms;

   size_t ls;

   const char *s = lua_tolstring(L, lua_upvalueindex(1), &ls);

   const char *p = lua_tostring(L, lua_upvalueindex(2));

   const char *src;

   ms.L = L;

   ms.src_init = s;

   ms.src_end = s+ls;

   for (src = s + (size_t)lua_tointeger(L, lua_upvalueindex(3));

        src <= ms.src_end;

        src++) {

     const char *e;

     ms.level = 0;

     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);

     }

   }

   return 0;  /* not found */

 }

 

 

 static int gmatch (lua_State *L) {

   luaL_checkstring(L, 1);

   luaL_checkstring(L, 2);

   lua_settop(L, 2);

   lua_pushinteger(L, 0);

   lua_pushcclosure(L, gmatch_aux, 3);

   return 1;

 }

 

 

 static int gfind_nodef (lua_State *L) {

   return luaL_error(L, LUA_QL("string.gfind") " was renamed to "

                        LUA_QL("string.gmatch"));

 }

 

 

 static void add_s (MatchState *ms, luaL_Buffer *b, const char *s,

                                                    const char *e) {

   size_t l, i;

   const char *news = lua_tolstring(ms->L, 3, &l);

   for (i = 0; i < l; i++) {

     if (news[i] != L_ESC)

       luaL_addchar(b, news[i]);

     else {

       i++;  /* skip ESC */

       if (!isdigit(uchar(news[i])))

         luaL_addchar(b, news[i]);

       else if (news[i] == '0')

           luaL_addlstring(b, s, e - s);

       else {

         push_onecapture(ms, news[i] - '1', s, e);

         luaL_addvalue(b);  /* add capture to accumulated result */

       }

     }

   }

 }

 

 

 static void add_value (MatchState *ms, luaL_Buffer *b, const char *s,

                                                        const char *e) {

   lua_State *L = ms->L;

   switch (lua_type(L, 3)) {

     case LUA_TNUMBER:

     case LUA_TSTRING: {

       add_s(ms, b, s, e);

       return;

     }

     case LUA_TFUNCTION: {

       int n;

       lua_pushvalue(L, 3);

       n = push_captures(ms, s, e);

       lua_call(L, n, 1);

       break;

     }

     case LUA_TTABLE: {

       push_onecapture(ms, 0, s, e);

       lua_gettable(L, 3);

       break;

     }

   }

   if (!lua_toboolean(L, -1)) {  /* nil or false? */

     lua_pop(L, 1);

     lua_pushlstring(L, s, e - s);  /* keep original text */

   }

   else if (!lua_isstring(L, -1))

     luaL_error(L, "invalid replacement value (a %s)", luaL_typename(L, -1)); 

   luaL_addvalue(b);  /* add result to accumulator */

 }

 

 

 static int str_gsub (lua_State *L) {

   size_t srcl;

   const char *src = luaL_checklstring(L, 1, &srcl);

   const char *p = luaL_checkstring(L, 2);

   int  tr = lua_type(L, 3);

   int max_s = luaL_optint(L, 4, srcl+1);

   int anchor = (*p == '^') ? (p++, 1) : 0;

   int n = 0;

   MatchState ms;

   luaL_Buffer b;

   luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||

                    tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,

                       "string/function/table expected");

   luaL_buffinit(L, &b);

   ms.L = L;

   ms.src_init = src;

   ms.src_end = src+srcl;

   while (n < max_s) {

     const char *e;

     ms.level = 0;

     e = match(&ms, src, p);

     if (e) {

       n++;

       add_value(&ms, &b, src, e);

     }

     if (e && e>src) /* non empty match? */

       src = e;  /* skip it */

     else if (src < ms.src_end)

       luaL_addchar(&b, *src++);

     else break;

     if (anchor) break;

   }

   luaL_addlstring(&b, src, ms.src_end-src);

   luaL_pushresult(&b);

   lua_pushinteger(L, n);  /* number of substitutions */

   return 2;

 }

 

 /* }====================================================== */

 

 

 /* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */

 #define MAX_ITEM	512

 /* valid flags in a format specification */

 #define FLAGS	"-+ #0"

 /*

 ** maximum size of each format specification (such as '%-099.99d')

 ** (+10 accounts for %99.99x plus margin of error)

 */

 #define MAX_FORMAT	(sizeof(FLAGS) + sizeof(LUA_INTFRMLEN) + 10)

 

 

 static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {

   size_t l;

   const char *s = luaL_checklstring(L, arg, &l);

   luaL_addchar(b, '"');

   while (l--) {

     switch (*s) {

       case '"': case '\\': case '\n': {

         luaL_addchar(b, '\\');

         luaL_addchar(b, *s);

         break;

       }

       case '\r': {

         luaL_addlstring(b, "\\r", 2);

         break;

       }

       case '\0': {

         luaL_addlstring(b, "\\000", 4);

         break;

       }

       default: {

         luaL_addchar(b, *s);

         break;

       }

     }

     s++;

   }

   luaL_addchar(b, '"');

 }

 

 static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {

   const char *p = strfrmt;

   while (*p != '\0' && strchr(FLAGS, *p) != NULL) p++;  /* skip flags */

   if ((size_t)(p - strfrmt) >= sizeof(FLAGS))

     luaL_error(L, "invalid format (repeated flags)");

   if (isdigit(uchar(*p))) p++;  /* skip width */

   if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */

   if (*p == '.') {

     p++;

     if (isdigit(uchar(*p))) p++;  /* skip precision */

     if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */

   }

   if (isdigit(uchar(*p)))

     luaL_error(L, "invalid format (width or precision too long)");

   *(form++) = '%';

   strncpy(form, strfrmt, p - strfrmt + 1);

   form += p - strfrmt + 1;

   *form = '\0';

   return p;

 }

 

 

 static void addintlen (char *form) {

   size_t l = strlen(form);

   char spec = form[l - 1];

   strcpy(form + l - 1, LUA_INTFRMLEN);

   form[l + sizeof(LUA_INTFRMLEN) - 2] = spec;

   form[l + sizeof(LUA_INTFRMLEN) - 1] = '\0';

 }

 

 

 static int str_format (lua_State *L) {

   int arg = 1;

   size_t sfl;

   const char *strfrmt = luaL_checklstring(L, arg, &sfl);

   const char *strfrmt_end = strfrmt+sfl;

   luaL_Buffer b;

   luaL_buffinit(L, &b);

   while (strfrmt < strfrmt_end) {

     if (*strfrmt != L_ESC)

       luaL_addchar(&b, *strfrmt++);

     else if (*++strfrmt == L_ESC)

       luaL_addchar(&b, *strfrmt++);  /* %% */

     else { /* format item */

       char form[MAX_FORMAT];  /* to store the format (`%...') */

       char buff[MAX_ITEM];  /* to store the formatted item */

       arg++;

       strfrmt = scanformat(L, strfrmt, form);

       switch (*strfrmt++) {

         case 'c': {

           sprintf(buff, form, (int)luaL_checknumber(L, arg));

           break;

         }

         case 'd':  case 'i': {

           addintlen(form);

           sprintf(buff, form, (LUA_INTFRM_T)luaL_checknumber(L, arg));

           break;

         }

         case 'o':  case 'u':  case 'x':  case 'X': {

           addintlen(form);

           sprintf(buff, form, (unsigned LUA_INTFRM_T)luaL_checknumber(L, arg));

           break;

         }

         case 'e':  case 'E': case 'f':

         case 'g': case 'G': {

           sprintf(buff, form, (double)luaL_checknumber(L, arg));

           break;

         }

         case 'q': {

           addquoted(L, &b, arg);

           continue;  /* skip the 'addsize' at the end */

         }

         case 's': {

           size_t l;

           const char *s = luaL_checklstring(L, arg, &l);

           if (!strchr(form, '.') && l >= 100) {

             /* no precision and string is too long to be formatted;

                keep original string */

             lua_pushvalue(L, arg);

             luaL_addvalue(&b);

             continue;  /* skip the `addsize' at the end */

           }

           else {

             sprintf(buff, form, s);

             break;

           }

         }

         default: {  /* also treat cases `pnLlh' */

           return luaL_error(L, "invalid option " LUA_QL("%%%c") " to "

                                LUA_QL("format"), *(strfrmt - 1));

         }

       }

       luaL_addlstring(&b, buff, strlen(buff));

     }

   }

   luaL_pushresult(&b);

   return 1;

 }

 

 

 static const luaL_Reg strlib[] = {

   {"byte", str_byte},

   {"char", str_char},

   {"dump", str_dump},

   {"find", str_find},

   {"format", str_format},

   {"gfind", gfind_nodef},

   {"gmatch", gmatch},

   {"gsub", str_gsub},

   {"len", str_len},

   {"lower", str_lower},

   {"match", str_match},

   {"rep", str_rep},

   {"reverse", str_reverse},

   {"sub", str_sub},

   {"upper", str_upper},

   {NULL, NULL}

 };

 

 

 static void createmetatable (lua_State *L) {

   lua_createtable(L, 0, 1);  /* create metatable for strings */

   lua_pushliteral(L, "");  /* dummy string */

   lua_pushvalue(L, -2);

   lua_setmetatable(L, -2);  /* set string metatable */

   lua_pop(L, 1);  /* pop dummy string */

   lua_pushvalue(L, -2);  /* string library... */

   lua_setfield(L, -2, "__index");  /* ...is the __index metamethod */

   lua_pop(L, 1);  /* pop metatable */

 }

 

 

 /*

 ** Open string library

 */

 LUALIB_API int luaopen_string (lua_State *L) {

   luaL_register(L, LUA_STRLIBNAME, strlib);

 #if defined(LUA_COMPAT_GFIND)

   lua_getfield(L, -1, "gmatch");

   lua_setfield(L, -2, "gfind");

 #endif

   createmetatable(L);

   return 1;

 }