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;    }    default: {      luaL_argerror(L, 3, "string/function/table expected");       return;    }  }  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 max_s = luaL_optint(L, 4, srcl+1);  int anchor = (*p == '^') ? (p++, 1) : 0;  int n = 0;  MatchState ms;  luaL_Buffer b;  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 '\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 (strchr(FLAGS, *p)) 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 to " LUA_QL("format"));        }      }      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;}