/*
 * This file has been modified for the cdrkit suite.
 *
 * The behaviour and appearence of the program code below can differ to a major
 * extent from the version distributed by the original author(s).
 *
 * For details, see Changelog file distributed with the cdrkit package. If you
 * received this file from another source then ask the distributing person for
 * a log of modifications.
 *
 */

/* @(#)overlap.c	1.11 04/02/20 J. Schilling from cdparanoia-III-alpha9.8 */
/*
 *	Modifications to make the code portable Copyright (c) 2002 J. Schilling
 */
/*
 * CopyPolicy: GNU Public License 2 applies
 * Copyright (C) by Monty (xiphmont@mit.edu)
 *
 * Statistic code and cache management for overlap settings
 *
 */

#include <mconfig.h>
#include <stdxlib.h>
#include <standard.h>
#include <utypes.h>
#include "p_block.h"
#include "cdda_paranoia.h"
#include "overlap.h"
#include "isort.h"

void paranoia_resetcache(cdrom_paranoia *p);
void paranoia_resetall(cdrom_paranoia *p);
void i_paranoia_trim(cdrom_paranoia *p, long beginword, long endword);
void offset_adjust_settings(cdrom_paranoia *p, void (*callback)(long, int));
void offset_add_value(cdrom_paranoia *p, offsets *o, long value, 
							 void (*callback)(long, int));

/*
 * Internal cache management
 */
void paranoia_resetcache(cdrom_paranoia *p)
{
	c_block		*c = c_first(p);
	v_fragment	*v;

	while (c) {
		free_c_block(c);
		c = c_first(p);
	}

	v = v_first(p);
	while (v) {
		free_v_fragment(v);
		v = v_first(p);
	}
}

void paranoia_resetall(cdrom_paranoia *p)
{
	p->root.returnedlimit = 0;
	p->dyndrift = 0;
	p->root.lastsector = 0;

	if (p->root.vector) {
		i_cblock_destructor(p->root.vector);
		p->root.vector = NULL;
	}
	paranoia_resetcache(p);
}

void i_paranoia_trim(cdrom_paranoia *p, long beginword, long endword)
{
	root_block	*root = &(p->root);

	if (root->vector != NULL) {
		long	target = beginword - p->maxdynoverlap;
		long	rbegin = cb(root->vector);
		long	rend = ce(root->vector);

		if (rbegin > beginword)
			goto rootfree;

		if (rbegin + p->maxdynoverlap < beginword) {
			if (target + MIN_WORDS_OVERLAP > rend)
				goto rootfree;

			{
				long	offset = target - rbegin;

				c_removef(root->vector, offset);
			}
		} {
			c_block	*c = c_first(p);

			while (c) {
				c_block	*next = c_next(c);

				if (ce(c) < beginword - p->maxdynoverlap)
					free_c_block(c);
				c = next;
			}
		}

	}
	return;

rootfree:

	i_cblock_destructor(root->vector);
	root->vector = NULL;
	root->returnedlimit = -1;
	root->lastsector = 0;

}

/*
 * Statistical and heuristic[al? :-] management
 */
void offset_adjust_settings(cdrom_paranoia *p, void (*callback)(long, int))
{
	if (p->stage2.offpoints >= 10) {
		/*
		 * drift: look at the average offset value.  If it's over one
		 * sector, frob it.  We just want a little hysteresis [sp?]
		 */
		long	av = (p->stage2.offpoints ? p->stage2.offaccum / p->stage2.offpoints : 0);

		if (abs(av) > p->dynoverlap / 4) {
			av = (av / MIN_SECTOR_EPSILON) * MIN_SECTOR_EPSILON;

			if (callback)
				(*callback) (ce(p->root.vector), PARANOIA_CB_DRIFT);
			p->dyndrift += av;

			/*
			 * Adjust all the values in the cache otherwise we get
			 * a (potentially unstable) feedback loop
			 */
			{
				c_block		*c = c_first(p);
				v_fragment	*v = v_first(p);

				while (v && v->one) {
					/*
					 * safeguard beginning bounds case with
					 * a hammer
					 */
					if (fb(v) < av || cb(v->one) < av) {
						v->one = NULL;
					} else {
						fb(v) -= av;
					}
					v = v_next(v);
				}
				while (c) {
					long	adj = min(av, cb(c));

					c_set(c, cb(c) - adj);
					c = c_next(c);
				}
			}

			p->stage2.offaccum = 0;
			p->stage2.offmin = 0;
			p->stage2.offmax = 0;
			p->stage2.offpoints = 0;
			p->stage2.newpoints = 0;
			p->stage2.offdiff = 0;
		}
	}
	if (p->stage1.offpoints >= 10) {
		/*
		 * dynoverlap: we arbitrarily set it to 4x the running
		 * difference value, unless min/max are more
		 */
		p->dynoverlap = (p->stage1.offpoints ? p->stage1.offdiff /
			p->stage1.offpoints * 3 : CD_FRAMEWORDS);

		if (p->dynoverlap < -p->stage1.offmin * 1.5)
			p->dynoverlap = -p->stage1.offmin * 1.5;

		if (p->dynoverlap < p->stage1.offmax * 1.5)
			p->dynoverlap = p->stage1.offmax * 1.5;

		if (p->dynoverlap < p->mindynoverlap)
			p->dynoverlap = p->mindynoverlap;
		if (p->dynoverlap > p->maxdynoverlap)
			p->dynoverlap = p->maxdynoverlap;

		if (callback)
			(*callback) (p->dynoverlap, PARANOIA_CB_OVERLAP);

		if (p->stage1.offpoints > 600) {
			/*
			 * bit of a bug; this routine is called too often
			 * due to the overlap mesh alg we use in stage 1
			 */
			p->stage1.offpoints /= 1.2;
			p->stage1.offaccum /= 1.2;
			p->stage1.offdiff /= 1.2;
		}
		p->stage1.offmin = 0;
		p->stage1.offmax = 0;
		p->stage1.newpoints = 0;
	}
}

void offset_add_value(cdrom_paranoia *p, offsets *o, long value, 
                      void (*callback)(long, int))
{
	if (o->offpoints != -1) {

		o->offdiff += abs(value);
		o->offpoints++;
		o->newpoints++;
		o->offaccum += value;
		if (value < o->offmin)
			o->offmin = value;
		if (value > o->offmax)
			o->offmax = value;

		if (o->newpoints >= 10)
			offset_adjust_settings(p, callback);
	}
}