#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>

extern const char *__progname;

static const char *videodev = "viddev";

#define MAXFRAMEBYTES (100<<20)

static int vfd;
static unsigned char *framebuf;
static unsigned int framelen;

static void open_video(void)
{
 vfd = open(videodev,O_RDWR,0);
 if (vfd < 0)
  { fprintf(stderr,"%s: %s: %s\n",__progname,videodev,strerror(errno));
    exit(1);
  }
}

static void size_frame(void)
{
 int lastlen;
 int goodcount;
 int n;
 int goodlen;

 framelen = 1000;
 lastlen = 0;
 framebuf = 0;
 while (1)
  { if (framelen != lastlen)
     { goodcount = 0;
       free(framebuf);
       framebuf = malloc(framelen+1);
       lastlen = framelen;
     }
    n = read(vfd,framebuf,framelen+1);
    if (n < 0)
     { fprintf(stderr,"%s: %s: read: %s\n",__progname,videodev,strerror(errno));
       exit(1);
     }
    if (n == 0)
     { fprintf(stderr,"%s: %s: read EOF\n",__progname,videodev);
       exit(1);
     }
    if (n > framelen)
     { framelen <<= 1;
     }
    else
     { if ((goodcount == 0) || (goodlen != n))
	{ goodlen = n;
	  goodcount = 1;
	}
       else
	{ goodcount ++;
	}
       if (goodcount > 4) break;
     }
  }
 framelen = n;
 fprintf(stderr,"framelen %d\n",n);
}

int main(void);
int main(void)
{
 int l;

 open_video();
 size_frame();
 while (1)
  { l = read(vfd,framebuf,framelen+1);
    if (l < 0)
     { fprintf(stderr,"%s: %s: read: %s\n",__progname,videodev,strerror(errno));
       exit(1);
     }
    if (l == 0)
     { fprintf(stderr,"%s: %s: read EOF\n",__progname,videodev);
       exit(1);
     }
    if (l < framelen)
     { fprintf(stderr,"%s: %s: short read (got %d wanted %d)\n",__progname,videodev,l,framelen);
       continue;
     }
    if (l > framelen)
     { fprintf(stderr,"%s: %s: long read (got %d wanted %d)\n",__progname,videodev,l,framelen);
       continue;
     }
    write(1,framebuf,framelen);
  }
}