User:Remark/dec-flipbook.c

// dec_flipbook
// written by remark
// thanks to steven & ludo

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

char key [0x40] = {
0xF7, 0x4C, 0x6A, 0x3A, 0xFB, 0x82, 0xA6, 0x37, 0x6E, 0x11, 0x38, 0xCF, 0xA0, 0xDD, 0x85, 0xC0,
0xC7, 0x9B, 0xC4, 0xD8, 0xDD, 0x28, 0x8A, 0x87, 0x53, 0x20, 0xEE, 0xE0, 0x0B, 0xEB, 0x43, 0xA0,
0xDB, 0x55, 0x0F, 0x75, 0x36, 0x37, 0xEB, 0x35, 0x6A, 0x34, 0x7F, 0xB5, 0x0F, 0x99, 0xF7, 0xEF,
0x43, 0x25, 0xCE, 0xA0, 0x29, 0x46, 0xD9, 0xD4, 0x4D, 0xBB, 0x04, 0x66, 0x68, 0x08, 0xF1, 0xF8
};

#define ERR(x ...) { printf(x); exit(1); }
#define PERR(x) { perror(x); exit(1); }

int fsize(FILE *f)
{
  int pos = ftell (f);
  fseek (f, 0, SEEK_END);
  int end = ftell (f);
  fseek (f, pos, SEEK_SET);
  return end;
}


int main(int argc, char* argv[])
{
  if(argc != 3)
  {
    printf("usage: %s <file_in> <file_out>\n", argv[0]);
    return 0;
  }
  
  FILE* f = fopen(argv[1], "rb");
  if(f == NULL)
  	PERR("fopen");
  	
  int len = fsize(f);
  char* buf = malloc(len);
  if(buf == NULL)
  	PERR("malloc");
  
  if(fread(buf,len,1,f) != 1)
  	PERR("fread");
  
  int i;
  for(i=0; i<len; i++)
  {
    buf[i] ^= key[i%0x40];
  }
  
  FILE* fout = fopen(argv[2], "wb+");
  if(fout == NULL) 
  	PERR("fopen");
  	
  if(fwrite(buf, len, 1, fout) != 1)
  	PERR("fwrite");
  
  
  free(buf);
  fclose(f);
  fclose(fout);
  
  return 0;
}