text: /****************************************************************************
   * Copyright (c) 1998-2017,2018 Free Software Foundation, Inc.              *
   *                                                                          *
   * Permission is hereby granted, free of charge, to any person obtaining a  *
   * copy of this software and associated documentation files (the            *
   * "Software"), to deal in the Software without restriction, including      *
   * without limitation the rights to use, copy, modify, merge, publish,      *
   * distribute, distribute with modifications, sublicense, and/or sell       *
   * copies of the Software, and to permit persons to whom the Software is    *
   * furnished to do so, subject to the following conditions:                 *
   *                                                                          *
   * The above copyright notice and this permission notice shall be included  *
   * in all copies or substantial portions of the Software.                   *
   *                                                                          *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
   * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
   * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
   * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
   * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
   * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
   *                                                                          *
   * Except as contained in this notice, the name(s) of the above copyright   *
   * holders shall not be used in advertising or otherwise to promote the     *
   * sale, use or other dealings in this Software without prior written       *
   * authorization.                                                           *
   ****************************************************************************/
  
  /****************************************************************************
   *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
   *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
   *     and: Thomas E. Dickey                        1996-on                 *
   ****************************************************************************/
  
  /*
   *	read_entry.c -- Routine for reading in a compiled terminfo file
   */
  
  #include <curses.priv.h>
  #include <hashed_db.h>
  
  #include <tic.h>
  
  MODULE_ID("$Id: read_entry.c,v 1.147 2018/04/01 01:32:39 tom Exp $")
  
  #define TYPE_CALLOC(type,elts) typeCalloc(type, (unsigned)(elts))
  
  #define MyNumber(n) (short) LOW_MSB(n)
  
  #define SIZEOF_32BITS 4
  
  #if NCURSES_USE_DATABASE
  #if NCURSES_EXT_NUMBERS
  static size_t
  convert_16bits(char *buf, NCURSES_INT2 *Numbers, int count)
  {
      int i;
      size_t j;
      size_t size = SIZEOF_SHORT;
      unsigned char ch;
      for (i = 0; i < count; i++) {
  	unsigned mask = 0xff;
  	Numbers[i] = 0;
  	for (j = 0; j < size; ++j) {
  	    ch = UChar(*buf++);
  	    Numbers[i] |= (ch << (8 * j));
  	    mask <<= 8;
  	}
  	if (ch & 0x80) {
  	    while (mask != 0) {
  		Numbers[i] |= (int) mask;
  		mask <<= 8;
  	    }
  	}
  	TR(TRACE_DATABASE, ("get Numbers[%d]=%d", i, Numbers[i]));
      }
      return size;
  }
  
  static size_t
  convert_32bits(char *buf, NCURSES_INT2 *Numbers, int count)
  {
      int i;
      size_t j;
      size_t size = SIZEOF_INT2;
      unsigned char ch;
  
      assert(sizeof(NCURSES_INT2) == size);
      for (i = 0; i < count; i++) {
  	Numbers[i] = 0;
  	for (j = 0; j < size; ++j) {
  	    ch = UChar(*buf++);
  	    Numbers[i] |= (ch << (8 * j));
  	}
  	/* "unsigned" and NCURSES_INT2 are the same size - no sign-extension */
  	TR(TRACE_DATABASE, ("get Numbers[%d]=%d", i, Numbers[i]));
      }
      return size;
  }
  #else
  static size_t
  convert_32bits(char *buf, NCURSES_INT2 *Numbers, int count)
  {
      int i, j;
      unsigned char ch;
      for (i = 0; i < count; i++) {
  	int value = 0;
  	for (j = 0; j < SIZEOF_32BITS; ++j) {
  	    ch = UChar(*buf++);
  	    value |= (ch << (8 * j));
  	}
  	if (value == -1)
  	    Numbers[i] = ABSENT_NUMERIC;
  	else if (value == -2)
  	    Numbers[i] = CANCELLED_NUMERIC;
  	else if (value > MAX_OF_TYPE(NCURSES_INT2))
  	    Numbers[i] = MAX_OF_TYPE(NCURSES_INT2);
  	else
  	    Numbers[i] = (short) value;
  	TR(TRACE_DATABASE, ("get Numbers[%d]=%d", i, Numbers[i]));
      }
      return SIZEOF_SHORT;
  }
  
  static size_t
  convert_16bits(char *buf, NCURSES_INT2 *Numbers, int count)
  {
      int i;
      for (i = 0; i < count; i++) {
  	if (IS_NEG1(buf + 2 * i))
  	    Numbers[i] = ABSENT_NUMERIC;
  	else if (IS_NEG2(buf + 2 * i))
  	    Numbers[i] = CANCELLED_NUMERIC;
  	else
  	    Numbers[i] = MyNumber(buf + 2 * i);
  	TR(TRACE_DATABASE, ("get Numbers[%d]=%d", i, Numbers[i]));
      }
      return SIZEOF_SHORT;
  }
  #endif
  
  static void
  convert_strings(char *buf, char **Strings, int count, int size, char *table)
  {
      int i;
      char *p;
  
      for (i = 0; i < count; i++) {
  	if (IS_NEG1(buf + 2 * i)) {
  	    Strings[i] = ABSENT_STRING;
  	} else if (IS_NEG2(buf + 2 * i)) {
  	    Strings[i] = CANCELLED_STRING;
  	} else if (MyNumber(buf + 2 * i) > size) {
  	    Strings[i] = ABSENT_STRING;
  	} else {
  	    Strings[i] = (MyNumber(buf + 2 * i) + table);
  	    TR(TRACE_DATABASE, ("Strings[%d] = %s", i, _nc_visbuf(Strings[i])));
  	}
  
  	/* make sure all strings are NUL terminated */
  	if (VALID_STRING(Strings[i])) {
  	    for (p = Strings[i]; p <= table + size; p++)
  		if (*p == '\0')
  		    break;
  	    /* if there is no NUL, ignore the string */
  	    if (p > table + size)
  		Strings[i] = ABSENT_STRING;
  	}
      }
  }
  
  static int
  fake_read(char *src, int *offset, int limit, char *dst, unsigned want)
  {
      int have = (limit - *offset);
  
      if (have > 0) {
  	if ((int) want > have)
  	    want = (unsigned) have;
  	memcpy(dst, src + *offset, (size_t) want);
  	*offset += (int) want;
      } else {
  	want = 0;
      }
      return (int) want;
  }
  
  #define Read(buf, count) fake_read(buffer, &offset, limit, (char *) buf, (unsigned) count)
  
  #define read_shorts(buf, count) \
  	(Read(buf, (count)*SIZEOF_SHORT) == (int) (count)*SIZEOF_SHORT)
  
  #define read_numbers(buf, count) \
  	(Read(buf, (count)*(unsigned)size_of_numbers) == (int) (count)*size_of_numbers)
  
  #define even_boundary(value) \
      if ((value) % 2 != 0) Read(buf, 1)
  #endif
  
  NCURSES_EXPORT(void)
  _nc_init_termtype(TERMTYPE2 *const tp)
  {
      unsigned i;
  
  #if NCURSES_XNAMES
      tp->num_Booleans = BOOLCOUNT;
      tp->num_Numbers = NUMCOUNT;
      tp->num_Strings = STRCOUNT;
      tp->ext_Booleans = 0;
      tp->ext_Numbers = 0;
      tp->ext_Strings = 0;
  #endif
      if (tp->Booleans == 0)
  	TYPE_MALLOC(NCURSES_SBOOL, BOOLCOUNT, tp->Booleans);
      if (tp->Numbers == 0)
  	TYPE_MALLOC(NCURSES_INT2, NUMCOUNT, tp->Numbers);
      if (tp->Strings == 0)
  	TYPE_MALLOC(char *, STRCOUNT, tp->Strings);
  
      for_each_boolean(i, tp)
  	tp->Booleans[i] = FALSE;
  
      for_each_number(i, tp)
  	tp->Numbers[i] = ABSENT_NUMERIC;
  
      for_each_string(i, tp)
  	tp->Strings[i] = ABSENT_STRING;
  }
  
  #if NCURSES_USE_DATABASE
  #if NCURSES_XNAMES
  static bool
  valid_shorts(char *buffer, int limit)
  {
      bool result = FALSE;
      int n;
      for (n = 0; n < limit; ++n) {
  	if (MyNumber(buffer + (n * 2)) > 0) {
  	    result = TRUE;
  	    break;
  	}
      }
      return result;
  }
  #endif
  
  /*
   * Return TGETENT_YES if read, TGETENT_NO if not found or garbled.
   */
  NCURSES_EXPORT(int)
  _nc_read_termtype(TERMTYPE2 *ptr, char *buffer, int limit)
  {
      int offset = 0;
      int name_size, bool_count, num_count, str_count, str_size;
      int i;
      char buf[MAX_ENTRY_SIZE + 2];
      char *string_table;
      unsigned want, have;
      bool need_ints;
      size_t (*convert_numbers) (char *, NCURSES_INT2 *, int);
      int size_of_numbers;
      int max_entry_size = MAX_ENTRY_SIZE;
  
      TR(TRACE_DATABASE,
         (T_CALLED("_nc_read_termtype(ptr=%p, buffer=%p, limit=%d)"),
  	(void *) ptr, buffer, limit));
  
      TR(TRACE_DATABASE, ("READ termtype header @%d", offset));
  
      memset(ptr, 0, sizeof(*ptr));
  
      /* grab the header */
      if (!read_shorts(buf, 6)
  	|| !IS_TIC_MAGIC(buf)) {
  	returnDB(TGETENT_NO);
      }
  #if NCURSES_EXT_NUMBERS
      if ((need_ints = (LOW_MSB(buf) == MAGIC2))) {
  	convert_numbers = convert_32bits;
  	size_of_numbers = SIZEOF_INT2;
      } else {
  	max_entry_size = MAX_ENTRY_SIZE1;
  	convert_numbers = convert_16bits;
  	size_of_numbers = SIZEOF_SHORT;
      }
  #else
      if ((need_ints = (LOW_MSB(buf) == MAGIC2))) {
  	convert_numbers = convert_32bits;
  	size_of_numbers = SIZEOF_32BITS;
      } else {
  	convert_numbers = convert_16bits;
  	size_of_numbers = SIZEOF_INT2;
      }
  #endif
  
      /* *INDENT-EQLS* */
      name_size  = MyNumber(buf + 2);
      bool_count = MyNumber(buf + 4);
      num_count  = MyNumber(buf + 6);
      str_count  = MyNumber(buf + 8);
      str_size   = MyNumber(buf + 10);
  
      TR(TRACE_DATABASE,
         ("TERMTYPE name_size=%d, bool=%d/%d, num=%d/%d str=%d/%d(%d)",
  	name_size, bool_count, BOOLCOUNT, num_count, NUMCOUNT,
  	str_count, STRCOUNT, str_size));
      if (name_size < 0
  	|| bool_count < 0
  	|| num_count < 0
  	|| str_count < 0
  	|| str_size < 0) {
  	returnDB(TGETENT_NO);
      }
  
      want = (unsigned) (str_size + name_size + 1);
      /* try to allocate space for the string table */
      if (str_count * SIZEOF_SHORT >= max_entry_size
  	|| (string_table = typeMalloc(char, want)) == 0) {
  	returnDB(TGETENT_NO);
      }
  
      /* grab the name (a null-terminated string) */
      want = min(MAX_NAME_SIZE, (unsigned) name_size);
      ptr->str_table = string_table;
      ptr->term_names = string_table;
      if ((have = (unsigned) Read(ptr->term_names, want)) != want) {
  	memset(ptr->term_names + have, 0, (size_t) (want - have));
      }
      ptr->term_names[want] = '\0';
      string_table += (want + 1);
  
      if (have > MAX_NAME_SIZE)
  	offset = (int) (have - MAX_NAME_SIZE);
  
      /* grab the booleans */
      if ((ptr->Booleans = TYPE_CALLOC(NCURSES_SBOOL,
  				     max(BOOLCOUNT, bool_count))) == 0
  	|| Read(ptr->Booleans, (unsigned) bool_count) < bool_count) {
  	returnDB(TGETENT_NO);
      }
  
      /*
       * If booleans end on an odd byte, skip it.  The machine they
       * originally wrote terminfo on must have been a 16-bit
       * word-oriented machine that would trap out if you tried a
       * word access off a 2-byte boundary.
       */
      even_boundary(name_size + bool_count);
  
      /* grab the numbers */
      if (!(ptr->Numbers = TYPE_CALLOC(NCURSES_INT2, max(NUMCOUNT, num_count)))
  	|| !read_numbers(buf, num_count)) {
  	returnDB(TGETENT_NO);
      }
      convert_numbers(buf, ptr->Numbers, num_count);
  
      if ((ptr->Strings = TYPE_CALLOC(char *, max(STRCOUNT, str_count))) == 0) {
  	returnDB(TGETENT_NO);
      }
  
      if (str_count) {
  	/* grab the string offsets */
  	if (!read_shorts(buf, str_count)) {
  	    returnDB(TGETENT_NO);
  	}
  	/* finally, grab the string table itself */
  	if (Read(string_table, (unsigned) str_size) != str_size) {
  	    returnDB(TGETENT_NO);
  	}
  	convert_strings(buf, ptr->Strings, str_count, str_size, string_table);
      }
  #if NCURSES_XNAMES
  
      ptr->num_Booleans = BOOLCOUNT;
      ptr->num_Numbers = NUMCOUNT;
      ptr->num_Strings = STRCOUNT;
  
      /*
       * Read extended entries, if any, after the normal end of terminfo data.
       */
      even_boundary(str_size);
      TR(TRACE_DATABASE, ("READ extended_header @%d", offset));
      if (_nc_user_definable && read_shorts(buf, 5) && valid_shorts(buf, 5)) {
  	int ext_bool_count = MyNumber(buf + 0);
  	int ext_num_count = MyNumber(buf + 2);
  	int ext_str_count = MyNumber(buf + 4);
  	int ext_str_usage = MyNumber(buf + 6);
  	int ext_str_limit = MyNumber(buf + 8);
  	unsigned need = (unsigned) (ext_bool_count + ext_num_count + ext_str_count);
  	int base = 0;
  
  	if ((int) need >= (max_entry_size / 2)
  	    || ext_str_usage >= max_entry_size
  	    || ext_str_limit >= max_entry_size
  	    || ext_bool_count < 0
  	    || ext_num_count < 0
  	    || ext_str_count < 0
  	    || ext_str_usage < 0
  	    || ext_str_limit < 0) {
  	    returnDB(TGETENT_NO);
  	}
  
  	ptr->num_Booleans = UShort(BOOLCOUNT + ext_bool_count);
  	ptr->num_Numbers = UShort(NUMCOUNT + ext_num_count);
  	ptr->num_Strings = UShort(STRCOUNT + ext_str_count);
  
  	TYPE_REALLOC(NCURSES_SBOOL, ptr->num_Booleans, ptr->Booleans);
  	TYPE_REALLOC(NCURSES_INT2, ptr->num_Numbers, ptr->Numbers);
  	TYPE_REALLOC(char *, ptr->num_Strings, ptr->Strings);
  
  	TR(TRACE_DATABASE, ("extended header: "
  			    "bool %d, "
  			    "number %d, "
  			    "string %d(%d:%d)",
  			    ext_bool_count,
  			    ext_num_count,
  			    ext_str_count,
  			    ext_str_usage,
  			    ext_str_limit));
  
  	TR(TRACE_DATABASE, ("READ %d extended-booleans @%d",
  			    ext_bool_count, offset));
  	if ((ptr->ext_Booleans = UShort(ext_bool_count)) != 0) {
  	    if (Read(ptr->Booleans + BOOLCOUNT, (unsigned)
  		     ext_bool_count) != ext_bool_count) {
  		returnDB(TGETENT_NO);
  	    }
  	}
  	even_boundary(ext_bool_count);
  
  	TR(TRACE_DATABASE, ("READ %d extended-numbers @%d",
  			    ext_num_count, offset));
  	if ((ptr->ext_Numbers = UShort(ext_num_count)) != 0) {
  	    if (!read_numbers(buf, ext_num_count)) {
  		returnDB(TGETENT_NO);
  	    }
  	    TR(TRACE_DATABASE, ("Before converting extended-numbers"));
  	    convert_numbers(buf, ptr->Numbers + NUMCOUNT, ext_num_count);
  	}
  
  	TR(TRACE_DATABASE, ("READ extended-offsets @%d", offset));
  	if ((ext_str_count + (int) need) >= (max_entry_size / 2)) {
  	    returnDB(TGETENT_NO);
  	}
  	if ((ext_str_count || need)
  	    && !read_shorts(buf, ext_str_count + (int) need)) {
  	    returnDB(TGETENT_NO);
  	}
  
  	TR(TRACE_DATABASE, ("READ %d bytes of extended-strings @%d",
  			    ext_str_limit, offset));
  
  	if (ext_str_limit) {
  	    ptr->ext_str_table = typeMalloc(char, (size_t) ext_str_limit);
  	    if (ptr->ext_str_table == 0) {
  		returnDB(TGETENT_NO);
  	    }
  	    if (Read(ptr->ext_str_table, (unsigned) ext_str_limit) != ext_str_limit) {
  		returnDB(TGETENT_NO);
  	    }
  	    TR(TRACE_DATABASE, ("first extended-string is %s", _nc_visbuf(ptr->ext_str_table)));
  	}
  
  	if ((ptr->ext_Strings = UShort(ext_str_count)) != 0) {
  	    int check = (ext_bool_count + ext_num_count + ext_str_count);
  
  	    TR(TRACE_DATABASE,
  	       ("Before computing extended-string capabilities "
  		"str_count=%d, ext_str_count=%d",
  		str_count, ext_str_count));
  	    convert_strings(buf, ptr->Strings + str_count, ext_str_count,
  			    ext_str_limit, ptr->ext_str_table);
  	    for (i = ext_str_count - 1; i >= 0; i--) {
  		TR(TRACE_DATABASE, ("MOVE from [%d:%d] %s",
  				    i, i + str_count,
  				    _nc_visbuf(ptr->Strings[i + str_count])));
  		ptr->Strings[i + STRCOUNT] = ptr->Strings[i + str_count];
  		if (VALID_STRING(ptr->Strings[i + STRCOUNT])) {
  		    base += (int) (strlen(ptr->Strings[i + STRCOUNT]) + 1);
  		    ++check;
  		}
  		TR(TRACE_DATABASE, ("... to    [%d] %s",
  				    i + STRCOUNT,
  				    _nc_visbuf(ptr->Strings[i + STRCOUNT])));
  	    }
  	    TR(TRACE_DATABASE, ("Check table-size: %d/%d", check, ext_str_usage));
  #if 0
  	    /*
  	     * Phasing in a proper check will be done "later".
  	     */
  	    if (check != ext_str_usage)
  		returnDB(TGETENT_NO);
  #endif
  	}
  
  	if (need) {
  	    if (ext_str_count >= (max_entry_size / 2)) {
  		returnDB(TGETENT_NO);
  	    }
  	    if ((ptr->ext_Names = TYPE_CALLOC(char *, need)) == 0) {
  		returnDB(TGETENT_NO);
  	    }
  	    TR(TRACE_DATABASE,
  	       ("ext_NAMES starting @%d in extended_strings, first = %s",
  		base, _nc_visbuf(ptr->ext_str_table + base)));
  	    convert_strings(buf + (2 * ext_str_count),
  			    ptr->ext_Names,
  			    (int) need,
  			    ext_str_limit, ptr->ext_str_table + base);
  	}
  
  	TR(TRACE_DATABASE,
  	   ("...done reading terminfo bool %d(%d) num %d(%d) str %d(%d)",
  	    ptr->num_Booleans, ptr->ext_Booleans,
  	    ptr->num_Numbers, ptr->ext_Numbers,
  	    ptr->num_Strings, ptr->ext_Strings));
  
  	TR(TRACE_DATABASE, ("extend: num_Booleans:%d", ptr->num_Booleans));
      } else
  #endif /* NCURSES_XNAMES */
      {
  	TR(TRACE_DATABASE, ("...done reading terminfo bool %d num %d str %d",
  			    bool_count, num_count, str_count));
  #if NCURSES_XNAMES
  	TR(TRACE_DATABASE, ("normal: num_Booleans:%d", ptr->num_Booleans));
  #endif
      }
  
      for (i = bool_count; i < BOOLCOUNT; i++)
  	ptr->Booleans[i] = FALSE;
      for (i = num_count; i < NUMCOUNT; i++)
  	ptr->Numbers[i] = ABSENT_NUMERIC;
      for (i = str_count; i < STRCOUNT; i++)
  	ptr->Strings[i] = ABSENT_STRING;
  
      returnDB(TGETENT_YES);
  }
  
  /*
   *	int
   *	_nc_read_file_entry(filename, ptr)
   *
   *	Read the compiled terminfo entry in the given file into the
   *	structure pointed to by ptr, allocating space for the string
   *	table.
   */
  NCURSES_EXPORT(int)
  _nc_read_file_entry(const char *const filename, TERMTYPE2 *ptr)
  /* return 1 if read, 0 if not found or garbled */
  {
      FILE *fp = 0;
      int code;
  
      if (_nc_access(filename, R_OK) < 0
  	|| (fp = fopen(filename, "rb")) == 0) {
  	TR(TRACE_DATABASE, ("cannot open terminfo %s (errno=%d)", filename, errno));
  	code = TGETENT_NO;
      } else {
  	int limit;
  	char buffer[MAX_ENTRY_SIZE + 1];
  
  	if ((limit = (int) fread(buffer, sizeof(char), sizeof(buffer), fp))
  	    > 0) {
  
  	    TR(TRACE_DATABASE, ("read terminfo %s", filename));
  	    if ((code = _nc_read_termtype(ptr, buffer, limit)) == TGETENT_NO) {
  		_nc_free_termtype2(ptr);
  	    }
  	} else {
  	    code = TGETENT_NO;
  	}
  	fclose(fp);
      }
  
      return (code);
  }
  
  #if USE_HASHED_DB
  /*
   * Return if if we can build the filename of a ".db" file.
   */
  static bool
  make_db_filename(char *filename, unsigned limit, const char *const path)
  {
      static const char suffix[] = DBM_SUFFIX;
  
      size_t lens = sizeof(suffix) - 1;
      size_t size = strlen(path);
      size_t test = lens + size;
      bool result = FALSE;
  
      if (test < limit) {
  	if (size >= lens
  	    && !strcmp(path + size - lens, suffix))
  	    _nc_STRCPY(filename, path, limit);
  	else
  	    _nc_SPRINTF(filename, _nc_SLIMIT(limit) "%s%s", path, suffix);
  	result = TRUE;
      }
      return result;
  }
  #endif
  
  /*
   * Return true if we can build the name of a filesystem entry.
   */
  static bool
  make_dir_filename(char *filename,
  		  unsigned limit,
  		  const char *const path,
  		  const char *name)
  {
      bool result = FALSE;
  
  #if NCURSES_USE_TERMCAP
      if (_nc_is_dir_path(path))
  #endif
      {
  	unsigned need = (unsigned) (LEAF_LEN + 3 + strlen(path) + strlen(name));
  
  	if (need <= limit) {
  	    _nc_SPRINTF(filename, _nc_SLIMIT(limit)
  			"%s/" LEAF_FMT "/%s", path, *name, name);
  	    result = TRUE;
  	}
      }
      return result;
  }
  
  static int
  lookup_b64(int *target, const char **source)
  {
      int result = 3;
      int j;
      /*
       * ncurses' quickdump writes only RFC 4648 "url/filename-safe" encoding,
       * but accepts RFC-3548
       */
      for (j = 0; j < 4; ++j) {
  	int ch = UChar(**source);
  	*source += 1;
  	if (ch >= 'A' && ch <= 'Z') {
  	    target[j] = (ch - 'A');
  	} else if (ch >= 'a' && ch <= 'z') {
  	    target[j] = 26 + (ch - 'a');
  	} else if (ch >= '0' && ch <= '9') {
  	    target[j] = 52 + (ch - '0');
  	} else if (ch == '-' || ch == '+') {
  	    target[j] = 62;
  	} else if (ch == '_' || ch == '/') {
  	    target[j] = 63;
  	} else if (ch == '=') {
  	    target[j] = 64;
  	    result--;
  	} else {
  	    result = -1;
  	    break;
  	}
      }
      return result;
  }
  
  static int
  decode_hex(const char **source)
  {
      int result = 0;
      int nibble;
      int ch;
  
      for (nibble = 0; nibble < 2; ++nibble) {
  	result <<= 4;
  	ch = UChar(**source);
  	*source += 1;
  	if (ch >= '0' && ch <= '9') {
  	    ch -= '0';
  	} else if (ch >= 'A' && ch <= 'F') {
  	    ch -= 'A';
  	    ch += 10;
  	} else if (ch >= 'a' && ch <= 'f') {
  	    ch -= 'a';
  	    ch += 10;
  	} else {
  	    result = -1;
  	    break;
  	}
  	result |= ch;
      }
      return result;
  }
  
  static int
  decode_quickdump(char *target, const char *source)
  {
      char *base = target;
      int result = 0;
  
      if (!strncmp(source, "b64:", 4)) {
  	source += 4;
  	while (*source != '\0') {
  	    int bits[4];
  	    int ch = lookup_b64(bits, &source);
  	    if (ch < 0 || (ch + target - base) >= MAX_ENTRY_SIZE) {
  		result = 0;
  		break;
  	    }
  	    result += ch;
  	    *target++ = (char) ((bits[0] << 2) | (bits[1] >> 4));
  	    if (bits[2] < 64) {
  		*target++ = (char) ((bits[1] << 4) | (bits[2] >> 2));
  		if (bits[3] < 64) {
  		    *target++ = (char) ((bits[2] << 6) | bits[3]);
  		}
  	    }
  	}
      } else if (!strncmp(source, "hex:", 4)) {
  	source += 4;
  	while (*source != '\0') {
  	    int ch = decode_hex(&source);
  	    if (ch < 0 || (target - base) >= MAX_ENTRY_SIZE) {
  		result = 0;
  		break;
  	    }
  	    *target++ = (char) ch;
  	    ++result;
  	}
      }
      return result;
  }
  
  /*
   * Build a terminfo pathname and try to read the data.  Returns TGETENT_YES on
   * success, TGETENT_NO on failure.
   */
  static int
  _nc_read_tic_entry(char *filename,
  		   unsigned limit,
  		   const char *const path,
  		   const char *name,
  		   TERMTYPE2 *const tp)
  {
      int code = TGETENT_NO;
  #if USE_HASHED_DB
      DB *capdbp;
  #endif
      char buffer[MAX_ENTRY_SIZE + 1];
      int used;
  
      TR(TRACE_DATABASE,
         (T_CALLED("_nc_read_tic_entry(file=%p, path=%s, name=%s)"),
  	filename, path, name));
  
      if ((used = decode_quickdump(buffer, path)) != 0
  	&& (code = _nc_read_termtype(tp, buffer, used)) == TGETENT_YES
  	&& _nc_name_match(tp->term_names, name, "|")) {
  	TR(TRACE_DATABASE, ("loaded quick-dump for %s", name));
      } else
  #if USE_HASHED_DB
  	if (make_db_filename(filename, limit, path)
  	    && (capdbp = _nc_db_open(filename, FALSE)) != 0) {
  
  	DBT key, data;
  	int reccnt = 0;
  	char *save = strdup(name);
  
  	memset(&key, 0, sizeof(key));
  	key.data = save;
  	key.size = strlen(save);
  
  	/*
  	 * This lookup could return termcap data, which we do not want.  We are
  	 * looking for compiled (binary) terminfo data.
  	 *
  	 * cgetent uses a two-level lookup.  On the first it uses the given
  	 * name to return a record containing only the aliases for an entry. 
  	 * On the second (using that list of aliases as a key), it returns the
  	 * content of the terminal description.  We expect second lookup to
  	 * return data beginning with the same set of aliases.
  	 *
  	 * For compiled terminfo, the list of aliases in the second case will
  	 * be null-terminated.  A termcap entry will not be, and will run on
  	 * into the description.  So we can easily distinguish between the two
  	 * (source/binary) by checking the lengths.
  	 */
  	while (_nc_db_get(capdbp, &key, &data) == 0) {
  	    char *have = (char *) data.data;
  	    used = (int) data.size - 1;
  
  	    if (*have++ == 0) {
  		if (data.size > key.size
  		    && IS_TIC_MAGIC(have)) {
  		    code = _nc_read_termtype(tp, have, used);
  		    if (code == TGETENT_NO) {
  			_nc_free_termtype2(tp);
  		    }
  		}
  		break;
  	    }
  
  	    /*
  	     * Just in case we have a corrupt database, do not waste time with
  	     * it.
  	     */
  	    if (++reccnt >= 3)
  		break;
  
  	    /*
  	     * Prepare for the second level.
  	     */
  	    key.data = have;
  	    key.size = used;
  	}
  
  	free(save);
      } else			/* may be either filesystem or flat file */
  #endif
      if (make_dir_filename(filename, limit, path, name)) {
  	code = _nc_read_file_entry(filename, tp);
      }
  #if NCURSES_USE_TERMCAP
      else if (code != TGETENT_YES) {
  	code = _nc_read_termcap_entry(name, tp);
  	_nc_SPRINTF(filename, _nc_SLIMIT(PATH_MAX)
  		    "%.*s", PATH_MAX - 1, _nc_get_source());
      }
  #endif
      returnDB(code);
  }
  #endif /* NCURSES_USE_DATABASE */
  
  /*
   * Find and read the compiled entry for a given terminal type, if it exists. 
   * We take pains here to make sure no combination of environment variables and
   * terminal type name can be used to overrun the file buffer.
   */
  NCURSES_EXPORT(int)
  _nc_read_entry2(const char *const name, char *const filename, TERMTYPE2 *const tp)
  {
      int code = TGETENT_NO;
  
      _nc_SPRINTF(filename, _nc_SLIMIT(PATH_MAX)
  		"%.*s", PATH_MAX - 1, name);
  
      if (strlen(name) == 0
  	|| strcmp(name, ".") == 0
  	|| strcmp(name, "..") == 0
  	|| _nc_pathlast(name) != 0
  	|| strchr(name, NCURSES_PATHSEP) != 0) {
  	TR(TRACE_DATABASE, ("illegal or missing entry name '%s'", name));
      } else {
  #if NCURSES_USE_DATABASE
  	DBDIRS state;
  	int offset;
  	const char *path;
  
  	_nc_first_db(&state, &offset);
  	code = TGETENT_ERR;
  	while ((path = _nc_next_db(&state, &offset)) != 0) {
  	    code = _nc_read_tic_entry(filename, PATH_MAX, path, name, tp);
  	    if (code == TGETENT_YES) {
  		_nc_last_db();
  		break;
  	    }
  	}
  #elif NCURSES_USE_TERMCAP
  	if (code != TGETENT_YES) {
  	    code = _nc_read_termcap_entry(name, tp);
  	    _nc_SPRINTF(filename, _nc_SLIMIT(PATH_MAX)
  			"%.*s", PATH_MAX - 1, _nc_get_source());
  	}
  #endif
      }
      return code;
  }
  
  #if NCURSES_EXT_NUMBERS
  /*
   * This entrypoint is used by tack.
   */
  NCURSES_EXPORT(int)
  _nc_read_entry(const char *const name, char *const filename, TERMTYPE *const tp)
  {
      TERMTYPE2 dummy;
      int rc;
      rc = _nc_read_entry2(name, filename, &dummy);
      if (rc == TGETENT_YES)
  	_nc_export_termtype2(tp, &dummy);
      return rc;
  }
  #endif
  