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#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <zlib.h>
#include "mystdlib.h"

#define XORLEN (29)
#define HUGEBLOCK (1024*1024)

int main(int argc, char **argv) {
  MAP in = map_file( argv[1], 1 );

  unsigned const char xorkey [XORLEN] = "Just for Fun. Linus Torvalds.";
  unsigned char input  [XORLEN];
  unsigned char output [HUGEBLOCK];
  char respath[32]; /* file_XXXXX\0 */
  int i, zres = 0, filenum = 0, resfile;
  size_t offs = 0, reported = 0;

  z_stream z; memset( &z, 0, sizeof(z));

  while( offs < in->size - XORLEN ) {
    for( i=0; i<XORLEN; ++i ) input[i] = in->addr[offs+i] ^ xorkey[i];
    z.next_in  = input;  z.avail_in = XORLEN;
    z.next_out = output; z.avail_out = HUGEBLOCK;
    inflateInit( &z ); zres = inflate( &z, Z_NO_FLUSH );
    if( (zres != Z_OK) && (zres != Z_STREAM_END) )
      goto error_continue;

    z.next_in  = in->addr + offs + XORLEN; z.avail_in = in->size - offs - XORLEN;
    while( zres == Z_OK ) zres = inflate( &z, Z_NO_FLUSH );

    if( zres != Z_STREAM_END ) {
error_continue:
      inflateEnd(&z); memset( &z, 0, sizeof(z));
      offs++;
      continue;
    }

    sprintf( respath, "file_%05X", filenum++ );
    resfile = open( respath, O_RDWR | O_CREAT, 0644 );
    if( resfile < 0 ) {
      fprintf( stderr, "Could not open output file %s\n", respath );
      exit(1);
    }
    write( resfile, output, z.total_out );
    close( resfile );
    offs += z.total_in;

    if( reported < ( offs * 10 ) / in->size ) {
      reported++;
      printf( "%zd%% ", 10 * reported );
      fflush( stdout );
    }

    inflateEnd(&z); memset( &z, 0, sizeof(z));
  }
  unmap_file(&in);
}