#define _LARGEFILE64_SOURCE 1

#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <limits.h>
#include <unistd.h>
#include <time.h>
#include <string.h>
#include <stdarg.h>

#define DEF_BLOCK 1024

#ifndef LLONG_MAX
#   define LLONG_MAX	9223372036854775807LL
#endif

char *pname;

static void msg(const char *fmt,...)
{
va_list ap;
time_t tm=time(NULL);
char *ts=ctime(&tm),*s;

	if ((s=strchr(ts,'\n'))) *s='\0';
	fprintf(stderr,"%s: %s - ",pname,ts);
	va_start(ap,fmt);
	vfprintf(stderr,fmt,ap);
	va_end(ap);
	fputc('\n',stderr);
}

int main(int argc,char **argv)
{
int block=DEF_BLOCK,r,fd;
char *buf;
long long offs=0,offs2=0,totsize=-1,forcedsize=0;

	pname=argv[0];
	if (argc>1) {
		if ((fd=open(argv[1],O_RDONLY
#ifdef O_BINARY
		|O_BINARY
#endif
		))==-1) {
			msg("open(\"%s\") error: %m",argv[1]);
			return(EXIT_FAILURE);
			}
		if (argc>2) {
			block=atoi(argv[2]);
			if (block<1||block>=INT_MAX) {
				block=DEF_BLOCK;
				msg("Forced block size %d",block);
				}
			}
		if (argc>3) {
			forcedsize=atoll(argv[3]);
			if (forcedsize<1||forcedsize>=LLONG_MAX) {
				forcedsize=0;
				msg("Total size NOT forced");
				}
			}
		}
	else fd=STDIN_FILENO;
	if (!(buf=malloc(block))) {
		msg("Error allocating buffer, size=%d",block);
		return(EXIT_FAILURE);
		}
	if (!(totsize=forcedsize)) {
		if ((totsize=lseek64(fd,0,SEEK_END))>0) {
			if ((offs2=lseek64(fd,0,SEEK_SET)))
				msg("Error back-lseek64(0,SEEK_SET)=%Ld: %m",offs2);
			}
		}
	if (totsize)
		msg("Starting, size=%Ld...",totsize);
	else
		msg("Starting, size unknown...",totsize);

	while (errno=0,(r=read(fd,buf,block))) {
		if (r<0) {
			msg("read %Ld:%Ld(%u): %m",offs,offs+block,block);
			if (fd==STDIN_FILENO) {
				msg("Error skipping from stdin not supported!");
				return(EXIT_FAILURE);
				}
			offs+=block;
			if ((offs2=lseek64(STDIN_FILENO,offs,SEEK_SET))!=offs) { /* FIXME */
				msg("Error recovery lseek64(%Ld,SEEK_SET)=%Ld: %m",offs,offs2);
				return(EXIT_FAILURE);
				}
			continue;
			}
		offs+=r;
		printf("%Ld",offs);
		if (totsize>0) printf("/%Ld",totsize);
		putchar('\r');
		fflush(stdout);
		}
	msg("Finished, total read %Ld.",offs);
	return(EXIT_SUCCESS);
}