edit.c

COP8 CPU的一个解释型BASIC源码

////////////////////////////////////////////////////////////////
//
//                S C R I P T H E R M
//             A SCRIPTABLE THERMOMETER
// 
// entry of the National Semiconductor COP8FLASH Design Contest
//        submitted by Alberto Ricci Bitti (C) 2001
//              [e-mail]
//
//--------------------------------------------------------------
//       FOR A BETTER VIEW SET TAB SIZE=4, INDENT SIZE=4
//--------------------------------------------------------------
// FILE   : edit.c
// PURPOSE: Simple full-screen editor for small files. 
//          Very portable, just redefine peek_ram() and 
//          poke_ram() to suit your edit buffer 
//          implementation. 
//
////////////////////////////////////////////////////////////////

#include "types.h"
#include "ascii.h"
#include "serial.h"
#include "memory.h"
#include "lcd.h"
#include "main.h"
#include "edit.h"

// codes used for full screen navigation and for deleting a character

#define KEY_BACKSP	0x7F
#define KEY_UP		0x0B
#define KEY_DOWN	0x0A
#define KEY_LEFT	0x08
#define KEY_RIGHT	0x09
#define KEY_CANC	0x18

static unsigned int first_visible = 0;  //address of the first visible line
static unsigned int current = 0;        //cursor address
static unsigned char modified = 0;      //flags buffer changes

//given an address, returns the beginning of the line that incudes it
static unsigned int line_start( unsigned int pos)
{
	while (pos > 0)
	{
		if ( peek_ram(--pos) == END_OF_LINE )
		{	pos++; 	break; };
	};
	return pos;
}


//given an address, returns the position of next line start
static unsigned int next_line(unsigned int pos)
{	unsigned char c;

	c = peek_ram(pos);
	while( (c != 0) && (c != END_OF_LINE) )
	{
		c = peek_ram(++pos);
	};
	if (c != 0)
		pos++;
	return pos;
}


static void cursor_forward(void)
{
	if ( peek_ram(current) != 0 )
		current++;
}


static void cursor_back(void)
{
	if (current > 0) 
		current--;
}


static void cursor_up(void)
{
	cursor_back();
	current = line_start( current );
}


static void cursor_down(void)
{
	current = next_line( current );
}

//inserts a character at current cursor position
static void ins(unsigned char replacer)
{
	unsigned int pos = current;
	unsigned char replaced;
	
	if (current < RAM_SIZE -1) 
	{
		modified = 1;
		while (1) 
		{
			replaced = peek_ram(pos);
			poke_ram(pos++, replacer);
			if (replacer == 0) 
				break;
			replacer = replaced;
		};
	}
	cursor_forward();
}

//deletes a character at the current cursor position
static void del(void)
{
	unsigned int pos = current;
	
	modified = 1;
	while (peek_ram(pos) != 0)
	{
		poke_ram( pos, peek_ram(pos+1) );
		pos++;
	}
}

// redraws the screen
static void refresh(void)
{	
	unsigned int i;
	unsigned char r=0, c=0, char_buf;

	
	//if current not shown, scroll window back
	while (first_visible > current)
		first_visible = line_start( --first_visible );

	do
	{
		i = first_visible;
		LCD_locate(0,0);
		do
		{
			//take note of cursor position
			if (i==current)	{	r = cursor_row; c = cursor_col; };
			
			char_buf = peek_ram(i);
			//in case replace end of file with end of line
			LCD_putchar( (unsigned char) (char_buf ? char_buf : END_OF_LINE) );
			i++;
		//repeat until buffer end or screen end
		} while ( ! (char_buf == 0 || cursor_row == 0 && cursor_col == 0) );
		
		//if current not shown, scroll window forward and repeat
		if (i <= current)					
		{
			first_visible = next_line( first_visible );
			continue;
		};
	} while (i <= current);

	//clear space to end of screen...
	while(cursor_row != 0 || cursor_col != 0)
		LCD_putchar(' ');
	//...and restore cursor
	LCD_locate(r,c);
	LCD_move_cursor(r,c);
}

//full screen edit, places the cursor to the specified position
unsigned char edit_program(unsigned int cursor)
{
	unsigned int k;
	
	modified = 0;
	current = cursor;
	first_visible = line_start(cursor);
	LCD_clear_text();
	do
	{
		if ( !com_pending() )   refresh();

		while( !com_pending() && flags.program) 
		{ /* loop intentionally void*/ };

        if (! flags.program)    
        {
            //tricky: hide cursor
            LCD_move_cursor(0, 40); 
            return modified;
        };

		switch( k = com_getchar() )
		{
		case KEY_UP:
			cursor_up();
			break;
		case KEY_DOWN:
			cursor_down();
			break;
		case KEY_LEFT:
			cursor_back();
			break;
		case KEY_RIGHT:
			cursor_forward();
			break;
		case KEY_CANC:
			del();
			break;
		case KEY_BACKSP:
			if (current > 0)
			{
				cursor_back();
				del();
			};
			break;
		case END_OF_LINE:
			ins( END_OF_LINE );
			break;
		default:
			if ( k > 31 && k < 128 )
				ins( (unsigned char) k );
			break;
		};
	} while (1); 
}