#include <stdio.h>
#include <string.h>
int fsize(FILE *sizefile)
{
	int curpos,length;
	curpos=ftell(sizefile);
	fseek(sizefile,0L,SEEK_END);
	length=ftell(sizefile);
	fseek(sizefile, curpos, SEEK_SET);
	return length;
}
void strfix(char *str)
{
	if((str[0]>=48)&&(str[0]<=57))
		str[0]=0;
	for(int i=0;i<8;i++)
	{
		if((str[i]>=97)&&(str[i]<=122))
			str[i]-=32;
		if((str[i]<48)||((str[i]>57)&&(str[i]<65))||(str[i]>90))
		{
			for(;i<8;i++)
				str[i]=0;
		}
	}
}
void main(int argc, char* argv[])
{
	char filetitle[8];
	char* newfilename;
	char* filecontenceptr=strdup("\x00");
	char* ext;
	char* lastslash;
	FILE *readfile,*writefile;
	if((argc!=2)&&(argc!=3)&&(argc!=4)) printf("Usage: TxttoCal source (destination) (name)");
	else
	{
		if (argc==2)
		{
			ext=strrchr(argv[1],'.')!=0 ? strrchr(argv[1],'.') : strrchr(argv[1],0);
			newfilename=strdup("");
			strncat(newfilename,argv[1],ext-argv[1]);
			strcat(newfilename,".83p");
			lastslash=strrchr(argv[1],'\\')!=0 ? strrchr(argv[1],'\\') : argv[1]-1;
		}
		if ((argc==3)||(argc==4))
		{
			newfilename=strdup(argv[2]);
			if(argc==3)
			{
				ext=strrchr(newfilename,'.')!=0 ? strrchr(newfilename,'.') : strrchr(newfilename,0);
				lastslash=strrchr(newfilename,'\\')!=0 ? strrchr(newfilename,'\\') : newfilename-1;
			}
			else
			{
				ext=strrchr(argv[3],0);
				lastslash=argv[3]-1;
			}
		}
		if(strcmp(argv[1],newfilename)==0)
		{
			printf("Destination and source are the same!");
		}
		else
		{
			if(ext-lastslash>9)
			{
				strncpy(filetitle,lastslash+1,8);
			}
			else
			{
				strncpy(filetitle,lastslash+1,ext-lastslash-1);
				filetitle[ext-lastslash-1]=0;
			}
			strfix(filetitle);
			if(filetitle[0]==0)
			{
				printf("Error generating file name!");
			}
			else
			{
				readfile=fopen(argv[1],"rb");
				if(!readfile) printf("\"%s\" is not found!",argv[1]);
				else
				{
					writefile=fopen(newfilename,"wb");
					if(!writefile) printf("Error writing to \"%s\"!",newfilename);
					else
					{
						unsigned char* filecontence = NULL;
						int filesize=fsize(readfile);
						filecontence=new unsigned char[filesize+86];
						memcpy(filecontence,"**TI83**\x1A\x0A\x00",11);
						memcpy(filecontence+11,"Qwerty Text Document\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",42);
						unsigned short num1=filesize+29;
						memcpy(filecontence+53,&num1,2);
						memcpy(filecontence+55,"\x0B\x00",2);
						num1=filesize+14;
						memcpy(filecontence+57,&num1,2);
						memcpy(filecontence+59,"\x06",1);
						memcpy(filecontence+60,filetitle,8);
						memcpy(filecontence+68,&num1,2);
						num1=filesize+12;
						memcpy(filecontence+70,&num1,2);
						memcpy(filecontence+72,"QWERTY Text\x00",12);
						fread(filecontence+84,filesize,1,readfile);
						num1=0;
						for(int i=55;i<=filesize+83;i++)
							num1+=filecontence[i];
						memcpy(filecontence+84+filesize,&num1,2);
						fwrite(filecontence,filesize+86,1,writefile);
						delete filecontence;
						printf("Success! \"%s\" converted to \"%s\".",argv[1],newfilename);
					}
				}
			}
		}
	}
}