In comp.sys.raspberry-pi, Charlie Gibbs   wrote:
> On 2020-08-20, Eli the Bearded  wrote:
> > In comp.sys.raspberry-pi, Charlie Gibbs   wrote:
> >> Wow, we've come a long way from the Andalusian Video Snail
> >> (which, unfortunately, I can no longer find).
> > https://grox.net/misc/vt/
> > snails.vt
> Many thanks.  I've filed this one.

I basically completely rewrote slowcat.c today:

https://gist.github.com/Eli-the-Bearded/162ad5989cc5b95c4b18758dd9da0780

(Source also at end of post, for future proofing.)

It makes snails.vt display well now. Suggested usage:

slowcat -b 9600 snails.vt

Where -b means "emulate baud rate" instead of the old "specify a delay".
That's just a simplicity of usage fix. The real fix is disabling the
stdio buffering, so the delays are more accurate. I also now fixed it
so it now process STDIN or use multiple files.

Elijah
------
/*
 * Inspired by, but a nearly complete rewrite of:
 *    slowcat.c - slow down the display of a file
 *    copyright (c) 2001,2002,2007  dave w capella   All Rights Reserved
 * found here:
 *    https://grox.net/software/mine/slowcat/
 * in August 2020.
 *
 * Original license (unchanged):
 *  *  distributed under the terms of the GNU Public license
 *  *
 *  *  There is NO WARRANTY, and NO SUPPORT WHATSOEVER.
 *
 * Original build / install unchanged:
 *  * building: make slowcat && mv slowcat $HOME/bin
 *  * (assuming that you have a personal bin directory)
 *
 * Usage vastly changed. "slowcat -h" will show usage now.
 *
 */

#include 
#include 
#include 
#include 

int debug = 0;
char version[] = "2020 Aug 20: first rewrite by Eli the Bearded";

void show_version(char *name) {
 printf("%s version %s\n", name, version);
}

void usage(FILE *where, char *name) {
 fprintf(where,"usage: %s\n", name);
 fprintf(where,"\t  slowcat -b BAUDRATE [ filename ... ]\n");
 fprintf(where,"\t  slowcat -d USECONDS [ filename ... ]\n");

 fprintf(where,"\nAdditional options:\n");
 fprintf(where,"\t          -v         be more verbose\n");
 fprintf(where,"\t          -V         show version\n");
 fprintf(where,"\t          -h         show this help\n");

 fprintf(where,"\nRuns something like basic cat(1), but slows the\n");
 fprintf(where,"output down to emulate a BAUDRATE connection (of\n");
 fprintf(where,"75 to 128000) or with an explicit delay between\n");
 fprintf(where,"bytes output of 1 to 20000 useconds. Recall that\n");
 fprintf(where,"baud is a rate of bits per second, so 1200 baud\n");
 fprintf(where,"is one bit ever 833.3 useconds, one byte every\n");
 fprintf(where,"6666.4 useconds, and 150 bytes per second.\n");
}

int main(int argc, char **argv) {
 int c, option;
 useconds_t usecs = 100;
 long baud;
 FILE *fp;
 char *fnam;

 while ( (option = getopt(argc, argv, "b:d:vVh")) != -1 ) {
  switch (option) {
   case 'v':
    debug = 1;
    break;

   case 'b':
    baud = strtoul( optarg, NULL, 10);
    /* 75 is the lowest generally accepted baud
     * rate, but even the Bell 101 modem did 110.
     * At the other end, 128k baud is ISDN.
     */
    if(baud <= 75) {
     baud = 75;
    } else if (baud > 128000L) {
     baud = 128000;
    }
    usecs = 8000000 / baud;
    break;

   case 'd':
    usecs = strtoul(argv[2],NULL,10);
    if(usecs  20000) {
     usecs = 100;
    }
    break;

   case '?':
    fprintf(stderr, "Unrecognized option: %c\n", optopt);
    usage(stderr, argv[0]);
    exit(1);

   case 'V':
    show_version(argv[0]);
    exit(0);
    break;

   case 'h':
    usage(stdout, argv[0]);
    exit(0);
    break;
  } /* switch */
 } /* while */


 setbuf(stdout, NULL);

        if ( optind != argc ) {
  fnam = argv[optind++];
  fp = fopen( fnam, "r");
  if(fp == NULL) {
   fprintf(stderr,"Filename %s errored out\n",fnam);
   exit(2);
  }
 } else {
  fp = stdin;
 }

 do {
  setbuf(fp, NULL);

  while ( (c = fgetc( fp )) != EOF ) {
   putchar(c);
   usleep(usecs);
  }

  fclose(fp);
  fnam = argv[optind++];

  if ( optind <= argc ) {
   fp = fopen( fnam, "r");
   if(fp == NULL) {
    fprintf(stderr,"Filename %s errored out\n",fnam);
    exit(2);
   }
  }
 } while ( optind <= argc );

 if (debug) {
  printf("\nDelay used: %lu useconds.\n", (unsigned long) usecs);
 }
 return (0);
}
/* EOF */

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