Synopsis: Condensing multiple messages. February 97
From erwin@pip.dknet.dk Thu Mar 20 16:46:10 1997
To: MERC/Envy Mailing List <merc-l@webnexus.com>
Subject: Simple message condensing

I have implemented a simple way to condense multiple identical messages
that follow each other. Rather than seeing: 

A cityguard is here.
A cityguard is here.

You'd see:

(x2) A cityguard is here.

What I am doing is to remember the length of the last printed line via
write_to_buffer: next time write_to_buffer is used, if the line of this
new message matches the old one I compare it with the old message, and if
it matches, I increase a counter and bail out, not appending the identical
string. 

This works on one-line strings only, that are sent one line at the time:
so it wouldn't for example condense two identical lines when a help file
is displayed.

If the message does not match, and the counter is more than 1, I change
the last part of the buffer into "(x%d) %s" where %d is the repeat count
and %s is the string.

I also check for count > 1 in process_output.

This is the rough code; you'll have to modify it to fit with your
write_to_buffer:

	
	/* Check if we want to repeat */
	if (d->last_len && d->last_len == length && d->outtop >= length)
		/* The strings have the same length: compare last length bytes in outbuf now */
		if (!memcmp(buf, d->outbuf + d->outtop - length, length))
		{
			d->last_count++;
			return;
		}

	/* Now that we know we have another string, check if there is an old string that needs
	   to have its count data written
    */
    
    if (d->last_count > 1)
    {
    	/* We only allow this if we can do it without expanding the buffer */
    	if (d->outtop + 16 < d->outsize)
    	{
    		char new_buf[d->last_len + 16];
    		int len;
    		
    		len = sprintf (new_buf, "(x%d) ", d->last_count);
    		memcpy (new_buf+len, d->outbuf + d->outtop - d->last_len, d->last_len);
    		memcpy (d->outbuf + d->outtop - d->last_len, new_buf, len + d->last_len);
    		d->outtop += len;
    	}
    }	   


   	d->last_count = 1;

	/* Only consider this if the string is not a multiline one */
   	if (real_len > 10 && newlines == 1)
	   	d->last_len = length;
	else
		d->last_len = 0;

In process output, repeat the if (d->last_count) code and set d->last_len
to 0. I should make this into a separate function, but I just added this
today :P

real_len is the length of the string without color; newlines is the number
of \ns there.

The variable-size array is gccism; it's not much different from char
*new_buf = alloca(d->last_len+16);

Tell me if you implement this and find it useful :)

==============================================================================
Erwin Andreasen  Viby J, Denmark   Computer Science Student at Aarhus Business
erwin@pip.dknet.dk        <URL:http://pip.dknet.dk/~pip1773/>          College
==============================================================================