lstrlib.c

Ubuntu packages of security software。 相当不错的源码

          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;
}