/* fii_fccomp.c -  code used to delta compress colors. */

#include "aai86.h"
#include "aaflisav.h"
#include "aafii.h"

/* fii_fccomp - compress an rgb triples color map just doing 'skip' compression */
Cbuf *fii_fccomp(Cmap *s1, Cmap *s2, USHORT *cbuf, int count)
{
USHORT wcount, i;
Cbuf *c;
USHORT op_count;
USHORT dif_count;
USHORT same_count;
USHORT next_match;
USHORT bcount;
Cmap *s2x;
USHORT c3;

c = (Cbuf *)(cbuf+1);
op_count = 0;
count *= 3;
wcount = i86_wcompare(s1, s2, count>>1);
wcount <<= 1;
if (wcount == count)
	return(c);	/* stupid way to say got nothing... */
for (;;)
	{
	/* first find out how many words to skip... */
	c3 = (i86_bcompare(s1, s2, count)/3);
	wcount = c3*3;
	if ((count -= wcount) == 0)
		goto OUT;	/* same until the end... */
	*c++ = c3;
	s1 += wcount;
	s2 += wcount;
	op_count++;

	/* figure out how long until the next worthwhile "skip" */
	dif_count = 0;
	bcount = count;
	for (;;)
		{
		wcount = i86_bcontrast(s1,s2,bcount)/3;
		dif_count += wcount;
		wcount *= 3;
		s1 += wcount;
		s2 += wcount;
		bcount -= wcount;
		if (bcount >= 3)
			{
			if ((wcount = i86_bcompare(s1,s2,3)) == 3)
				{
				break;
				}
			else
				{
				dif_count += 1;
				s1 += 3;
				s2 += 3;
				bcount -= 3;
				}
			}
		else
			{
			break;
			}
		}
	*c++ = dif_count;
	dif_count *= 3;
	s2 -= dif_count;
	count -= dif_count;
	for (;;)
		{
		if (dif_count == 0)
			break;
		dif_count -= 1;
		*c++ = *s2++;
		}
	if (count <= 0)
		break;
	}
OUT:
*cbuf = op_count;
return(i86_enorm_ptr(c));
}