/*

    int2tap - Convert an Intel segment file to a loadable Spectrum tape file

    Copyright (C) 2004  Ian Cowburn (ianc@noddybox.demon.co.uk)

    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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    -------------------------------------------------------------------------

*/
static const char id[]="$Id$";

#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#include "tap.h"

static const char header_id[]=I2T_TAP_H;


/* ---------------------------------------- CONSTANTS
*/
#undef TRUE
#undef FALSE

#define TRUE	1
#define FALSE	0


/* ---------------------------------------- TYPES
*/


/* ---------------------------------------- GLOBALS
*/
extern const char	*progname;

static FILE		*fp;
static int		file_no;


/* ---------------------------------------- PRIVATE FUNCTIONS
*/
unsigned char TapWord(unsigned w, unsigned char chk)
{
    putc(w&0xff,fp);
    chk^=w&0xff;
    putc(w>>8,fp);
    chk^=w>>8;
    return chk;
}

unsigned char TapByte(unsigned char c, unsigned char chk)
{
    putc(c,fp);
    chk^=c;
    return chk;
}

unsigned char TapString(char *p, int len, unsigned char chk)
{
    while(len--)
    {
    	chk=TapByte(*p++,chk);
    }

    return chk;
}

unsigned char TapStream(const unsigned char p[0x10000],
			unsigned addr, unsigned len, unsigned char chk)
{
    while(len--)
    {
    	chk=TapByte(p[addr],chk);
	addr=(addr+1)&0xffff;
    }

    return chk;
}

/* ---------------------------------------- INTERFACES
*/

int TapOpen(const char *filename)
{
    file_no=0;

    if (!(fp=fopen(filename,"wb")))
    {
    	fprintf(stderr,"%s: Failed to create %s\n",progname,filename);
    }

    return fp!=NULL;
}


void TapWrite(const unsigned char mem[0x1000],
	      unsigned addr, unsigned len, int is_code)
{
    char name[11]={0};
    unsigned char chk;

    sprintf(name,"%10.10d",file_no);
    file_no=(file_no+1)%10000;

    /* Output file header
    */
    chk=TapWord(19,chk);
    chk=TapByte(0,chk);

    if (is_code)
    {
	chk=TapByte(3,chk);
    }
    else
    {
	chk=TapByte(3,chk);
    }

    chk=TapString(name,10,chk);
    chk=TapWord(len,chk);

    if (is_code)
    {
    	chk=TapWord(addr,chk);
	chk=TapWord(32768,chk);
    }
    else
    {
    	chk=TapWord(0,chk);
	chk=TapWord(0,chk);
    }

    TapByte(chk,0);

    /* Output file data
    */
    chk=0;

    chk=TapWord(len+2,chk);
    chk=TapStream(mem,addr,len,chk);
    TapByte(chk,0);
}


void TapClose(void)
{
    if (fp)
    {
    	fclose(fp);
	fp=NULL;
    }
}


/* END OF FILE */