mesg.c

hex editor for editing all files

/*
 * mesg.c   - message loop
 * 
 *        Author: David Scott
 *  Date Started: 25-Aug-2000
 * 
 *  Modification history:
 *
 *  .000830  initial beta release
 */



#include <curses.h>
#include <unistd.h>
#include <stdlib.h>
#include <ctype.h>
#include "hview.h"

int x,y;

/* 
 * the main message loop 
 * inputs: pointing to current window
 *         input stream
 */

void message_loop( WINDOW *wp, FILE *in )
{
	int offset, pagelen,bytesread;
	int ch;
        bool in_echo; 

	in_echo = FALSE;

	offset = 0;
	pagelen = (screen_y-4)*16;
	bytesread=printscr( wp, in, 0 );

	move(1,10);
	refresh();
	x = 10; y = 1;
	noecho();

         
	while (((ch = getch()) != 'q') && (ch != 'Q'))
	{
		switch(toupper(ch))
		{
			case KEY_DOWN:  /* down arrow or control-n */  
			case CTRL('N'):	y++;
					if( y > screen_y-4 )
					{
						if( offset != totalbytes)
						{
							offset+=16;
					  		move(0,60);
					        	printheader(wp,bytesread=printscr(wp,in, offset));						
						}						
						y--;
					}
					if( OFFSET(x,y) > bytesread)
						y--;
					break;
			
			case KEY_UP: 	/* up arrow or control-p */
			case CTRL('P'): y-=1;
					if( y < 1 )
					{
/*						if( in_echo )
						{
							
						}*/
						if( offset != 0 )
						{
							offset-=16;
							move(0,60);
							printheader(wp,bytesread=printscr(wp,in,offset));
						}
						y++;
						
					}
					break; 

			case KEY_LEFT:	/* left arrow or control-f */
			case CTRL('F'): if( (x-3) < 10 )
					{
						if( y == 1 )
						{ 
							if( offset != 0 )
							{
								offset-=16;
								move(0,60);
								printheader(wp,bytesread=printscr(wp,in,offset));
								x=55;
							}
						}
						else
						{
							y--;
							x=55;
						}
					}
					else
					{
						x = ((x-3)<10)?10:x-3;
					}
					break;

			case KEY_RIGHT: /* right arrow or control-b */
			case CTRL('B'): if( ((x+3) > 56)  )
					{
					   	if( y < screen_y-4)
						{
							x=10;
							y++;
						}
						else if (offset != totalbytes)
						{
							offset+=16;
					  		move(0,60);
					        	printheader(wp,bytesread=printscr(wp,in, offset));						
							x = 10;
						}
					}
					else
					{
						x+=3;
					}

					if(OFFSET(x+3,y) > bytesread)
						x-=3;
					break;
			
			case CTRL('V'): /* Control-V (Page Down) */
					offset =  ((offset+pagelen)<=abs(totalbytes))?offset+pagelen:offset;
					move( 0,60 );
					printheader(wp, bytesread=printscr(wp,in,offset));
					x = 10; y=1;
					break;

			case CTRL('Y'): /* Control-Y (Page up) */
					offset = ((offset-pagelen) >= 0)?offset-pagelen:0;
					move( 0,60 );
					printheader(wp, bytesread=printscr(wp,in,offset));
					x = 10, y = 1;
					break;

			case CTRL('R'): /* Control-R (Refresh) */
					move(0,60);
					printheader(wp, bytesread=printscr(wp,in,offset));
					break;

			case 'M': 	/* M - modify */
					in_echo = !in_echo;
					move(0,0);
					printw("%c", (in_echo)?'*':' ');
					move(y,x);
					break;

			case 'W':       /* W -write block out */
					writeblock( in, offset, bytesread ) ;
					break;
					
			default:        if( in_echo )
						edit(toupper(ch));

		}
		move( y, x );
		refresh();
	}
	echo(); 

}

void edit(int ch)
{

	int z;

	if( isxdigit( ch ) )
	{						
		if(!( (y < 1) || (y > screen_y -4)))
		{
			move(y,x);
			printw("%c", toupper(ch)  );

			/*
			 * calc offset once instead of every time we need 
			 * the value. 
			 */

			z = OFFSET(x,y);
	
			/* 
			 * this checks to see if the next position of the cursor
			 * will be a break.  
 			 *
	 		 * If it is then we are dealing with the low nibble so 
			 * mask off the high nibble and add in the new bits.
			 * else mask off the high nibble, shift the current bits 
			 * into the high nibble and mask off the low.
			 */
	
			buffer[z] = ((x+1)%3)? 
				(xtoi(ch)<<4) + (buffer[z] & 0x0f): 
				xtoi(ch) + (buffer[z] & 0xf0);

			move(y,XOFFSET(x)+60);
			printch(buffer[z]); 
			refresh();

			x += ((x+1)%3)?1:2;
			if (x > 56 && y <=(screen_y -4))
			{
				y++; x=10;
			}
			move(y,x);
			refresh();
		}
	}
}


int writeblock( FILE *in, int offset, int len)
{

	int x, ch, err;
	FILE *tmp;

	err = 1;
	fseek(in, offset,SEEK_SET);
	for( x = 0; x<len && err!=EOF;x++ )
	{
		fprintf(tmp,"%x ",x);
	 	err = fputc(buffer[x],in);
	}
	
	return err;

}