libiberty/hex.c

/* Hex character manipulation support.
   Copyright (C) 1995-2025 Free Software Foundation, Inc.

This file is part of the libiberty library.
Libiberty is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

Libiberty is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with libiberty; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
Boston, MA 02110-1301, USA.  */

#include <stdio.h>  /* for EOF */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "libiberty.h"
#include "safe-ctype.h" /* for HOST_CHARSET_ASCII */

#if EOF != -1
 #error "hex.c requires EOF == -1"
#endif

/*

@deftypefn Extension void hex_init (void)

Initializes the array mapping the current character set to
corresponding hex values.  This function must be called before any
call to @code{hex_p} or @code{hex_value}.  If you fail to call it, a
default ASCII-based table will normally be used on ASCII systems.

@end deftypefn

@deftypefn Extension int hex_p (int @var{c})

Evaluates to non-zero if the given character is a valid hex character,
or zero if it is not.  Note that the value you pass will be cast to
@code{unsigned char} within the macro.

@end deftypefn

@deftypefn Extension {unsigned int} hex_value (int @var{c})

Returns the numeric equivalent of the given character when interpreted
as a hexadecimal digit.  The result is undefined if you pass an
invalid hex digit.  Note that the value you pass will be cast to
@code{unsigned char} within the macro.

The @code{hex_value} macro returns @code{unsigned int}, rather than
signed @code{int}, to make it easier to use in parsing addresses from
hex dump files: a signed @code{int} would be sign-extended when
converted to a wider unsigned type --- like @code{bfd_vma}, on some
systems.

@end deftypefn

@undocumented _hex_array_size
@undocumented _hex_bad
@undocumented _hex_value

*/


/* Are we ASCII? */
#if HOST_CHARSET == HOST_CHARSET_ASCII

const unsigned char _hex_value[_hex_array_size] =
{
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* NUL SOH STX ETX */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* EOT ENQ ACK BEL */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* BS  HT  LF  VT  */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* FF  CR  SO  SI  */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* DLE DC1 DC2 DC3 */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* DC4 NAK SYN ETB */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* CAN EM  SUB ESC */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* FS  GS  RS  US  */

  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* SP  !   "   #   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* $   %   &   '   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* (   )   *   +   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* ,   -   .   /   */
  0,        1,        2,        3,          /* 0   1   2   3   */
  4,        5,        6,        7,          /* 4   5   6   7   */
  8,        9,        _hex_bad, _hex_bad,   /* 8   9   :   ;   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* <   =   >   ?   */

  _hex_bad, 10,       11,       12,         /* @   A   B   C   */
  13,       14,       15,       _hex_bad,   /* D   E   F   G   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* H   I   J   K   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* L   M   N   O   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* P   Q   R   S   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* T   U   V   W   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* X   Y   Z   [   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* \   ]   ^   _   */

  _hex_bad, 10,       11,       12,         /* `   a   b   c   */
  13,       14,       15,       _hex_bad,   /* d   e   f   g   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* h   i   j   k   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* l   m   n   o   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* p   q   r   s   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* t   u   v   w   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* x   y   z   {   */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,   /* |   }   ~   DEL */

  /* The high half of unsigned char, all values are _hex_bad.  */
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,

  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,

  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,

  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
  _hex_bad, _hex_bad, _hex_bad, _hex_bad,
};
#define HEX_TABLE_INITIALIZED

#else

unsigned char _hex_value[_hex_array_size];

#endif /* not ASCII */

void
hex_init (void)
{
#ifndef HEX_TABLE_INITIALIZED
  int i;

  for (i=0; i<_hex_array_size; i++)
    {
      switch (i)
	{
	case '0': _hex_value[i] = 0; break;
	case '1': _hex_value[i] = 1; break;
	case '2': _hex_value[i] = 2; break;
	case '3': _hex_value[i] = 3; break;
	case '4': _hex_value[i] = 4; break;
	case '5': _hex_value[i] = 5; break;
	case '6': _hex_value[i] = 6; break;
	case '7': _hex_value[i] = 7; break;
	case '8': _hex_value[i] = 8; break;
	case '9': _hex_value[i] = 9; break;

	case 'a': case 'A': _hex_value[i] = 10; break;
	case 'b': case 'B': _hex_value[i] = 11; break;
	case 'c': case 'C': _hex_value[i] = 12; break;
	case 'd': case 'D': _hex_value[i] = 13; break;
	case 'e': case 'E': _hex_value[i] = 14; break;
	case 'f': case 'F': _hex_value[i] = 15; break;

	default:
	  _hex_value[i] = _hex_bad;
	  break;
	}
    }
#endif
}