/*
 * Copyright (c) 2001-2002, David Janssens
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS'
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "tgt.h"
#include "bio.h"
#include <stdlib.h>
#include <stdio.h>

/* <summary> */
/* Reset tag-tree. */
/* </summary> */
void tgt_reset(tgt_tree_t * tree)
{
	int i;
	/* new */
	if (!tree || tree == NULL)
		return;

	for (i = 0; i < tree->numnodes; i++) {
		tree->nodes[i].value = 999;
		tree->nodes[i].low = 0;
		tree->nodes[i].known = 0;
	}
}

/* <summary> */
/* Create tag-tree. */
/* </summary> */
tgt_tree_t *tgt_create(int numleafsh, int numleafsv)
{
	int nplh[32];
	int nplv[32];
	tgt_node_t *node;
	tgt_node_t *parentnode;
	tgt_node_t *parentnode0;
	tgt_tree_t *tree;
	int i, j, k;
	int numlvls;
	int n;

	tree = (tgt_tree_t *) malloc(sizeof(tgt_tree_t));
	tree->numleafsh = numleafsh;
	tree->numleafsv = numleafsv;

	numlvls = 0;
	nplh[0] = numleafsh;
	nplv[0] = numleafsv;
	tree->numnodes = 0;
	do {
		n = nplh[numlvls] * nplv[numlvls];
		nplh[numlvls + 1] = (nplh[numlvls] + 1) / 2;
		nplv[numlvls + 1] = (nplv[numlvls] + 1) / 2;
		tree->numnodes += n;
		++numlvls;
	} while (n > 1);

	/* ADD */
	if (tree->numnodes == 0) {
		free(tree);
		return NULL;
	}

	tree->nodes = (tgt_node_t *) malloc(tree->numnodes * sizeof(tgt_node_t));

	node = tree->nodes;
	parentnode = &tree->nodes[tree->numleafsh * tree->numleafsv];
	parentnode0 = parentnode;

	for (i = 0; i < numlvls - 1; ++i) {
		for (j = 0; j < nplv[i]; ++j) {
			k = nplh[i];
			while (--k >= 0) {
				node->parent = parentnode;
				++node;
				if (--k >= 0) {
					node->parent = parentnode;
					++node;
				}
				++parentnode;
			}
			if ((j & 1) || j == nplv[i] - 1) {
				parentnode0 = parentnode;
			} else {
				parentnode = parentnode0;
				parentnode0 += nplh[i];
			}
		}
	}
	node->parent = 0;

	tgt_reset(tree);

	return tree;
}

/* <summary> */
/* Destroy tag-tree. */
/* </summary> */
void tgt_destroy(tgt_tree_t * t)
{
	free(t->nodes);
	free(t);
}

/* <summary> */
/* Set the value of a leaf of the tag-tree. */
/* </summary> */
void tgt_setvalue(tgt_tree_t * tree, int leafno, int value)
{
	tgt_node_t *node;
	node = &tree->nodes[leafno];
	while (node && node->value > value) {
		node->value = value;
		node = node->parent;
	}
}

/* <summary> */
/* Encode the value of a leaf of the tag-tree. */
/* </summary> */
void tgt_encode(tgt_tree_t * tree, int leafno, int threshold)
{
	tgt_node_t *stk[31];
	tgt_node_t **stkptr;
	tgt_node_t *node;
	int low;

	stkptr = stk;
	node = &tree->nodes[leafno];
	while (node->parent) {
		*stkptr++ = node;
		node = node->parent;
	}

	low = 0;
	for (;;) {
		if (low > node->low) {
			node->low = low;
		} else {
			low = node->low;
		}

		while (low < threshold) {
			if (low >= node->value) {
				if (!node->known) {
					bio_write(1, 1);
					node->known = 1;
				}
				break;
			}
			bio_write(0, 1);
			++low;
		}

		node->low = low;
		if (stkptr == stk)
			break;
		node = *--stkptr;
	}

}

/* <summary> */
/* Decode the value of a leaf of the tag-tree. */
/* </summary> */
int tgt_decode(tgt_tree_t * tree, int leafno, int threshold)
{
	tgt_node_t *stk[31];
	tgt_node_t **stkptr;
	tgt_node_t *node;
	int low;

	stkptr = stk;
	node = &tree->nodes[leafno];
	while (node->parent) {
		*stkptr++ = node;
		node = node->parent;
	}

	low = 0;
	for (;;) {
		if (low > node->low) {
			node->low = low;
		} else {
			low = node->low;
		}
		while (low < threshold && low < node->value) {
			if (bio_read(1)) {
				node->value = low;
			} else {
				++low;
			}
		}
		node->low = low;
		if (stkptr == stk) {
			break;
		}
		node = *--stkptr;
	}

	return (node->value < threshold) ? 1 : 0;
}