// romto8xu.cpp : définit le point d'entrée pour l'application console.
//

#define PAGE_SIZE (16*1024)

#include "stdio.h"
#include "string.h"
#include "stdlib.h"

char rombuffer[0x400000];
int romind=0;
int romsize=0;

int romgetc()
{	unsigned char c = rombuffer[romind++];
	return c;
}

void readversion(int* a, int* b, int i)
{	*a=0;
	*b=0;
	int* t = a;
	while(rombuffer[i]!=' ' && rombuffer[i]!=0)
	{	char c = rombuffer[i];
		if(c!=' ' && c && c!='.')
			*t=(*t)*10+(c-'0');
		else if(c=='.')
			t=b;
		i++;
	}
}

int romfind(char* str)
{	int n = strlen(str);
	char* tmp = (char*) malloc(n+1);
	tmp[n]=0;
	int i;
	for(i=0;i<romsize;i++)
	{	memcpy(tmp,rombuffer+i,n);
		if(!strcmp(tmp,str))
			break;
	}
	if(i>=romsize) i=-1;
	free(tmp);
	return i;
}

int main(int argc, char* argv[])
{	char buffer[77],buffer2[17];
	char* hexa="0123456789ABCDEF";
	int mode, tromsize;
	int c,i,h=0,page=0;
	FILE* rom;
	FILE* upd;
	
	printf("\n+----------+\n");
	printf("! ROMto8XU !\n");
	printf("+----------+\n");
	printf(" X. Andreani\n\n");
	printf("Extracts a TI OS from a z80 Flash-ROM file\n");
	printf("and generates a matching update file.\n\n");
	printf("ROMs of the following models are supported:\n");
	printf("* TI-73\n");
	printf("* TI-83+\t* TI-83+SE\n");
	printf("* TI-84+\t* TI-84+SE\t* TI-84+nSpire(Keypad)\n");
	printf("* TI-84+C\n");
	printf("TI .clc files (ROM + RAM backup) are also supported.\n\n");
	printf("Update files  will be written in the .73u, .8xu or .8cu format.\n\n");
	printf("To be installable on a true calculator, the generated\n");
	printf("update file may need to be signed with the correct key.\n\n");
	if( argc<4 )
	{	printf("ERROR: too few arguments\n");
		printf("Usage: %s source.rom dest.8xu mode\n", argv[0]);
		printf(" where mode is 7 (TI-73), 3 (TI-83), 4 (TI-84+ 512bits RSA), 5 (TI-84+ 2048bits RSA), 6 (TI-84+C)\n");
		return 0;
	}
	mode=*argv[3]-'0';
	if(mode!=7 && mode!=3 && mode!=4 && mode!=5 && mode!=6)
	{	printf("ERROR: unknown mode\n");
		printf(" where mode is 7 (TI-73), 3 (TI-83), 4 (TI-84+ 512bits RSA), 5 (TI-84+ 2048bits RSA), 6 (TI-84+C)\n");
		return 0;
	}
	rom=fopen(argv[1],"rb");
	if(!rom)
	{	printf("Source file open error\n");
		return 0;
	}
	upd=fopen(argv[2],"w");
	if(!rom)
	{	fclose(rom);
		printf("Dest file open error\n");
		return 0;
	}
	fseek(rom,0,SEEK_END);
	tromsize=ftell(rom);
	fseek(rom,0,SEEK_SET);
	int npages = 0;
	romsize = PAGE_SIZE;
	while(tromsize>=2*romsize)
	{	romsize*=2;
	}
	npages = romsize/PAGE_SIZE;	
	fread(rombuffer, 1, romsize, rom);
	fclose(rom);

	printf("Detected ROM: %iKB (%i pages)\n",npages*PAGE_SIZE/1024,npages);
	int mpages = 0x20;
	int lpages = mpages-3;
	if( mode==6)
	{	mpages = 0x100;
		lpages = mpages-4;
	}
	int v1=0,v2=0;
	int b = romfind("BASE Code");
	if(b>0)
	{	readversion(&v1,&v2,b+10);
		printf("OS version: %i.%i\n",v1,v2);
	}
	else
		printf("Warning: version string not found\n");
	fwrite("**TIFL**",1,8,upd);
	fputc(v1,upd);
	fputc(v2,upd);
	fwrite("\1\0\1\1\1\1",1,7,upd);
	if(mode==7)
		fwrite("BASECODE",1,8,upd);
	else
		fwrite("basecode",1,8,upd);
	fwrite("\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0",1,23,upd);
	if(mode==7)
		fwrite("t",1,1,upd);
	else
		fwrite("s",1,1,upd);
	fwrite("#\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0",1,25,upd);
	if( mode==7 )
		fwrite("Ln\0:17000000800F0003801C80110280210180312880A0807F000380000B",1,61,upd);
	if( mode==3 )
		fwrite("Nn\0:18000000800F0000000080110480210180310D80A101807F0000000043",1,63,upd);
	if( mode==4 || mode==5)
		fwrite("˜Ö\n\0:1B000000800F0000000080110A80210280311580A103808112807F000000001C",1,69,upd);
	if( mode==6 )
		fwrite("—Ý\0:1B000000800F0000000080110F80210480310080A105808121807F0000000019",1,69,upd);
	fwrite("\n",1,1,upd);
	strcpy(buffer2,":0200000200xx..\n");
	strcpy(buffer,":20hhh000xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx..\n\0");
	fwrite(":00000001FF\n",1,12,upd);
	while(page<=lpages)
	{	printf("Extracting page %i...\n",page);
		buffer2[11]=hexa[page/16];
		buffer2[12]=hexa[page%16];
		int k=252-page;
		buffer2[13]=hexa[k/16];
		buffer2[14]=hexa[k%16];
		fwrite(buffer2,1,16,upd);
		while(h<2048)
		{	k=32;
			for(i=0;i<32;i++)
			{	c=romgetc();
				if((c==0x5A && page==0 && h==4)
					|| ((((mode==4 || mode==5) && page==0x1A) || (mode==6 && page==0xFA)) && (h>=0x400 && h<0x420)))
						c=0xFF;
				k=k+c;
				*(buffer+9+2*i)=hexa[(c-(c%16))/16];
	 			*(buffer+9+2*i+1)=hexa[c%16];
			}
			*(buffer+5)=hexa[h%16];
			*(buffer+4)=hexa[(h/16)%16];
			*(buffer+3)=hexa[h/256];
			k=k+(h%256)*16;
			k=k+h/16;
			k=k%256;
			k=(256-k)%256;
			buffer[73]=hexa[k/16];
			buffer[74]=hexa[k%16];
			fwrite(buffer, 1, 76, upd);
			h=h+2;
			if(h==1024)
			{	buffer2[12]='1';
				buffer2[13]='F';
				buffer2[14]='B';
				fwrite(buffer2,1,16,upd);
			}
		}
		h=1024;
		if(page==0) page++;
		page++;
		if(page==8)
		{	int t = 0;
			if(mode==6) // TI-84+C
				t = 28;
			else if(mode==4) // TI-84+ 512-bits RSA
				t = 12;
			else if(mode==5) // TI-84+ 2048-bits RSA
				t = 16;
			else // TI-73/83+
				t = 8;
			page=mpages-t;
			romind = (npages-t)*PAGE_SIZE;
		}
	}
	fwrite(":00000001FF\n",1,12,upd);
	romind = (npages-6)*PAGE_SIZE+0x100;
	*(buffer+9 )='0';
	*(buffer+10)='2';
	*(buffer+11)='0';
	*(buffer+12)='D';
	for(h=0;h<=4;h+=2)
	{		int k=32;
			for(i=0;i<32;i++)
			{	if(h==0 && i==0) c=0x02;
				else if(h==0 && i==1) c=0x0D;
				else c=romgetc();
				k=k+c;
				*(buffer+9+2*i)=hexa[(c-(c%16))/16];
	 			*(buffer+9+2*i+1)=hexa[c%16];
			}
			*(buffer+5)=hexa[h%16];
			*(buffer+4)=hexa[(h/16)%16];
			*(buffer+3)=hexa[h/256];
			k=k+(h%256)*16;
			k=k+h/16;
			k=k%256;
			k=(256-k)%256;
			buffer[73]=hexa[k/16];
			buffer[74]=hexa[k%16];
			fwrite(buffer, 1, 76, upd);
	}
	fwrite(":00000001FF   -- CONVERT 2.6 --\n",1,32,upd);
	fclose(upd);
	return 0;
}