Use this to slow down view of ascii anims (UNIX)

ewh...@uxa.cso.uiuc.edu (Buck Hodges) writes:

> Someone once posted a C program to do a similar thing which would of course 
> work on whatever system had a C compiler.  Maybe they'll post it again.

	Here is `slocat' C-program which was posted here some time
ago. I modified it to use usleep-function instead of dummy for loop,
so this version shouldn't jam the whole computer. 

	Altough usleep is included in standard libraries of most UNIX
systems I found that this is not the case for all systems. To be more
compatible I included it in the code. 

	`slocat' requires name of ascii file (animation) as
first argument and as second argument (optional) the lenght of delay in
milliseconds (default is 400). E.g. `slocat twilight.vt 500' 

	I am not sure wether the system calls are universal enough to
work in other environments than UNIX but it might be worth of try.
Please report any inconveniences caused.
	
------ cut here ------- cut here ------ cut here ------ cut here ------

/*
 *            slocat.c
 *      
 *    slocat <filename> [delay]
 *
 */ 

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <signal.h>
#include <sys/time.h>

#define DEFAULT_DELAY 400

void usleep (unsigned int);

main(int argc,char *argv[])
{
  FILE *f;
  unsigned long int delay;
  char c;

  if ( !argv[2] || (delay = atoi (argv[2])) <1 )
    delay=DEFAULT_DELAY;

  if (!argv[1]) {
    puts ("slocat: file not specified");
    exit (1);
  }

  if (!(f=fopen( argv[1], "r"))) {
    printf ("slocat: can not open %s\n",argv[1]);
    exit (2);
  }

  while ( !feof(f) ) {
    putc( getc(f), stdout );
    usleep (delay);
  }
  fclose(f);
}

void usleep(unsigned int usec)
{
  struct timeval timeout;
  if(usec == 0) 
    return;
  timeout.tv_sec = usec / 1000000;
  timeout.tv_usec = usec - 1000000 * timeout.tv_sec;
  select(1, NULL, NULL, NULL, &timeout);
}

------ cut here ------- cut here ------ cut here ------ cut here ------
	
	-Petri Paavilainen (ppa...@snakemail.hut.fi)

Use of usleep etc.

A much simpler and almost certainly much more portable method (and one that
could be done in almost any language) would be to output a number of NUL
characters after _each_ character output.  The more NULs the slower it goes!
I think almost any operating system/terminal will cope with this.

Just a suggestion.

Eddie