/*
 *  $Header: /cvs/faces/faces/compface/compress.c,v 1.2 2002/01/15 22:58:46 devface Exp $
 *
 *  Compface - 48x48x1 image compression and decompression
 *
 *  Copyright (c) 1990-2002 James Ashton - Sydney University
 *
 *  Permission is given to distribute these sources, as long as the
 *  copyright messages are not removed, and no monies are exchanged. 
 *
 *  No responsibility is taken for any errors on inaccuracies inherent
 *  either to the comments or the code of this program, but if reported
 *  to me, then an attempt will be made to fix them.
 */

#include "compface.h"

int
Same(f, wid, hei)
register char *f;
register int wid, hei;
{
	register char val, *row;
	register int x;

	val = *f;
	while (hei--)
	{
		row = f;
		x = wid;
		while (x--)
			if (*(row++) != val)
				return(0);
		f += WIDTH;
	}
	return 1;
}

int
AllBlack(f, wid, hei)
char *f;
int wid, hei;
{
	if (wid > 3)
	{
		wid /= 2;
		hei /= 2;
		return (AllBlack(f, wid, hei) && AllBlack(f + wid, wid, hei) &&
		       AllBlack(f + WIDTH * hei, wid, hei) &&
		       AllBlack(f + WIDTH * hei + wid, wid, hei));
    }
	else
		return (*f || *(f + 1) || *(f + WIDTH) || *(f + WIDTH + 1));
}

int
AllWhite(f, wid, hei)
char *f;
int wid, hei;
{
	return ((*f == 0) && Same(f, wid, hei));
}

void
PopGreys(f, wid, hei)
char *f;
int wid, hei;
{
	if (wid > 3)
	{
		wid /= 2;
		hei /= 2;
		PopGreys(f, wid, hei);
		PopGreys(f + wid, wid, hei);
		PopGreys(f + WIDTH * hei, wid, hei);
		PopGreys(f + WIDTH * hei + wid, wid, hei);
	}
	else
	{
		wid = BigPop(freqs);
		if (wid & 1)
			*f = 1;
		if (wid & 2)
			*(f + 1) = 1;
		if (wid & 4)
			*(f + WIDTH) = 1;
		if (wid & 8)
			*(f + WIDTH + 1) = 1;
        }
}

void
PushGreys(f, wid, hei)
char *f;
int wid, hei;
{
	if (wid > 3)
	{
		wid /= 2;
		hei /= 2;
		PushGreys(f, wid, hei);
		PushGreys(f + wid, wid, hei);
		PushGreys(f + WIDTH * hei, wid, hei);
		PushGreys(f + WIDTH * hei + wid, wid, hei);
    }
	else
		RevPush(freqs + *f + 2 * *(f + 1) + 4 * *(f + WIDTH) +
		  8 * *(f + WIDTH + 1));
}

void
UnCompress(f, wid, hei, lev)
register char *f;
register int wid, hei, lev;
{
	switch (BigPop(&levels[lev][0]))
	{
		case WHITE :
			return;
		case BLACK :
			PopGreys(f, wid, hei);
			return;
		default :
			wid /= 2;
			hei /= 2;
			lev++;
			UnCompress(f, wid, hei, lev);
			UnCompress(f + wid, wid, hei, lev);
			UnCompress(f + hei * WIDTH, wid, hei, lev);
			UnCompress(f + wid + hei * WIDTH, wid, hei, lev);
			return;
	}
}

void
Compress(f, wid, hei, lev)
register char *f;
register int wid, hei, lev;
{
	if (AllWhite(f, wid, hei))
	{
		RevPush(&levels[lev][WHITE]);
		return;
	}
	if (AllBlack(f, wid, hei))
	{
		RevPush(&levels[lev][BLACK]);
		PushGreys(f, wid, hei);
		return;
	}
	RevPush(&levels[lev][GREY]);
	wid /= 2;
	hei /= 2;
	lev++;
	Compress(f, wid, hei, lev);
	Compress(f + wid, wid, hei, lev);
	Compress(f + hei * WIDTH, wid, hei, lev);
	Compress(f + wid + hei * WIDTH, wid, hei, lev);
}

void
UnCompAll(fbuf)
char *fbuf;
{
	register char *p;

	BigClear();
	BigRead(fbuf);
	p = F;
	while (p < F + PIXELS)
		*(p++) = 0;
	UnCompress(F, 16, 16, 0);
	UnCompress(F + 16, 16, 16, 0);
	UnCompress(F + 32, 16, 16, 0);
	UnCompress(F + WIDTH * 16, 16, 16, 0);
	UnCompress(F + WIDTH * 16 + 16, 16, 16, 0);
	UnCompress(F + WIDTH * 16 + 32, 16, 16, 0);
	UnCompress(F + WIDTH * 32, 16, 16, 0);
	UnCompress(F + WIDTH * 32 + 16, 16, 16, 0);
	UnCompress(F + WIDTH * 32 + 32, 16, 16, 0);
}

void
CompAll(fbuf)
char *fbuf;
{
	Compress(F, 16, 16, 0);
	Compress(F + 16, 16, 16, 0);
	Compress(F + 32, 16, 16, 0);
	Compress(F + WIDTH * 16, 16, 16, 0);
	Compress(F + WIDTH * 16 + 16, 16, 16, 0);
	Compress(F + WIDTH * 16 + 32, 16, 16, 0);
	Compress(F + WIDTH * 32, 16, 16, 0);
	Compress(F + WIDTH * 32 + 16, 16, 16, 0);
	Compress(F + WIDTH * 32 + 32, 16, 16, 0);
	BigClear();
	while (NumProbs > 0)
		BigPush(ProbBuf[--NumProbs]);
	BigWrite(fbuf);
}