Re: Hex numbers

[Paul Davis <paul linuxaudiosystems com>]

some ideas from the world of C++. This is a C++ widget that filters
input at the keypress level and only allows hex digits to be entered.
i believe i've used it :)

--p


/*
    Copyright (C) 1999 Paul Barton-Davis 

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

    This program 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

    $Id: hexentry.h,v 1.2 2003/02/10 14:31:58 pbd Exp $
*/

#ifndef __gtkmmext_hexentry_h__
#define __gtkmmext_hexentry_h__

#include <gtk--.h>

namespace Gtkmmext {

class HexEntry : public Gtk::Entry

{
  public:
	/* Take a byte-level representation of a series of hexadecimal
	   values and use them to set the displayed text of the entry.
	   Eg. if hexbuf[0] = 0xff and hexbuf[1] = 0xa1 and buflen = 2,
	   then the text will be set to "ff a1".
	*/

	void set_hex (unsigned char *hexbuf, unsigned int buflen);

	/* puts byte-level representation of current entry text
	   into hexbuf, and returns number of bytes written there.

	   NOTE: this will release the existing memory pointed to
	   by hexbuf if buflen indicates that it is not long enough
	   to hold the new representation, and hexbuf is not zero.

	   If the returned length is zero, the contents of hexbuf 
	   are undefined.
	*/

	unsigned int get_hex (unsigned char *hexbuf, size_t buflen);

  private:
	gint key_press_event_impl (GdkEventKey *);
};

} /* namespace */

#endif /* __gtkmmext_hexentry_h__ */

/*
    Copyright (C) 2000 Paul Barton-Davis 

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

    This program 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

    $Id: hexentry.cc,v 1.3 2002/06/01 03:32:49 trutkin Exp $
*/

#include <stdio.h> /* for sprintf, sigh ... */
#include <string>
#include <ctype.h>

#include <gdk/gdkkeysyms.h>
#include <gtkmmext/hexentry.h>

using namespace std;
using namespace Gtkmmext;

gint
HexEntry::key_press_event_impl (GdkEventKey *ev)

{
	if ((ev->keyval >= GDK_a && ev->keyval <= GDK_f) ||
	    (ev->keyval >= GDK_A && ev->keyval <= GDK_A) ||
	    (ev->keyval >= GDK_0 && ev->keyval <= GDK_9) ||
	    ev->keyval == GDK_space || 
	    ev->keyval == GDK_Tab ||
	    ev->keyval == GDK_Return ||
	    ev->keyval == GDK_BackSpace ||
	    ev->keyval == GDK_Delete) {
		return Gtk::Entry::key_press_event_impl (ev);
	} else {
		gdk_beep ();
		return FALSE;
	}
}


void
HexEntry::set_hex (unsigned char *msg, unsigned int len) 
	
{
	/* create a textual representation of the MIDI message */
	
	if (msg && len) {
		char *rep;
		
		rep = new char[(len * 3) + 1];
		for (size_t i = 0; i < len; i++) {
			sprintf (&rep[i*3], "%02x ", msg[i]);
		}
		rep[len * 3] = '\0';
		set_text (rep);
		delete [] rep;
	} else {
		set_text ("");
	}
}

unsigned int
HexEntry::get_hex (unsigned char *hexbuf, size_t buflen)

{
	int fetched_len;
	char buf[3];
	string text = get_text();
	string::size_type length = text.length ();
	string::size_type offset;

	fetched_len = 0;
	buf[2] = '\0';
	offset = 0;

	while (1) {
		offset = text.find_first_of ("abcdef0123456789", offset);

		if (offset == string::npos) {
			break;
		}

		/* grab two characters, but no more */
		
		buf[0] = text[offset];

		if (offset < length - 1) {
			buf[1] = text[offset+1];
			offset += 2;
		} else {
			buf[1] = '\0';
			offset += 1;
		}

		hexbuf[fetched_len++] = (char) strtol (buf, 0, 16);
	}

	return fetched_len;
}