#include <stdio.h>
#include <curses.h>
#define CPL 16 //characters per line 
#define LPS 25 //lines per screen

int main(int argc,char *argv[]) {
 FILE *fp;
 int done=0;
 int in;
 int in2;
 int pos=0;
 int bottom;
 int top;
 int len=0;
 int i;
 int j;
 int mod=1;//1=hex 2=normal
 char cont[1024*1024];//lol. buffer overflow. use for *small* files. ;)
 memset(cont,0,1024*1024-1);
 if(!argv[1]) {
  printf("error.\n");
  return 0;
 }
 if(!(fp=fopen(argv[1],"rb"))) {
 } else {
  for(i=0;!feof(fp);i++) {
   fread(&cont[i],1,1,fp);
   len++;
  }
  done=0;
  fclose(fp);
 }
 initscr();
 cbreak();
 for( ; !done ; in=getch()) {
  if(in=='\x1b') {
   in=getch();
   if(in=='[') {
    in=getch();
    if(in=='A') {//up
     pos-=CPL;
    }
    if(in=='B') {//down
     pos+=CPL;
    }
    if(in=='C') {//right
     pos++;
    }
    if(in=='D') {//left
     pos--;
    }
    if(in=='G') {//page down
     pos+=CPL*LPS;
    }
    if(in=='I') {//page up
     pos-=CPL*LPS;
    }
    if(pos<0) {pos=0;}// :P
    if(pos>len) {pos=len;}
   } else if(in=='\x1b') {//double escape to exit and save.
    break;
   }
   //continue;
  }
  else {
   if(in=='\t') {
    mod=(mod)?0:1;
   }
   else if(in=='\b') {
    for(j=pos-1;j<len-1;j++) {
     cont[j]=cont[j+1];
    }
    cont[j]=0;
    pos--;
    len--;
   }
   else if(mod) { //hex mode?
    if(isxdigit(in)) {//get the first digit...
     in2=getch();
     if(isxdigit(in2)) {//is there an easier way? I made this up. :P
      in=(isdigit(in))?in-'0':toupper(in)-'A'+10;
      in2=(isdigit(in2))?in2-'0':toupper(in2)-'A'+10;
      //the chars were converted to ints...
      cont[pos++]=in*16+in2;
      len+=len<pos;
     }
    }
   } else { //text mode?
    cont[pos++]=in;
    len+=(len<pos);
   }
  }
  clear();
  bottom=0;
  //this makes it go a screen full at a time.
  bottom=(pos-(pos%(CPL*LPS)));
  top=bottom+(CPL*LPS);
  for(i=bottom;i<top && i < len+(CPL-(len%CPL));i++) {
   if(i%CPL==0) {
    printw("%.8x ",i);
   }
   if(i%CPL==8) {
    printw(" ");
   }
   if(pos==i) {
    attron(mod?A_REVERSE:A_BOLD);
   }
   if(i>=len) {
    printw("--");
   } else {
    printw("%.2hhx",cont[i]);
   }
   if(pos==i) {
    attroff(mod?A_REVERSE:A_BOLD);
   }
   printw(" ");
   if(i%CPL==(CPL-1)) {
    printw(" |");
    for(j=i-(CPL-1);j<=i;j++) {
     if(pos==j) {
      attron(mod?A_BOLD:A_REVERSE);
     }
     printw("%c",isprint(cont[j])?cont[j]:'.');
     if(pos==j) {
      attroff(mod?A_BOLD:A_REVERSE);
     }
    }
    printw("|%s",((j)==(CPL*LPS))?"":"\n");
   }
  }
 }
 nocbreak();
 endwin();
 if(!(fopen(argv[1],"wb"))) {
  fprintf(stderr,"couldn't create file!!! oh shit!\n");
  return 0;
 }
 for(i=0;i<len;i++) {
  fwrite(&cont[i],1,1,fp);
 }
 fclose(fp);
 return 0;
}