/**
 * Navit, a modular navigation system.
 * Copyright (C) 2005-2008 Navit Team
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA  02110-1301, USA.
 */

#include <stdio.h>
#include <string.h>
#include "debug.h"
#include "mg.h"

struct tree_hdr {
	/*unsigned int addr;
	unsigned int size;
	unsigned int low;*/
	unsigned char p[12];
};
static inline unsigned int tree_hdr_get_addr(struct tree_hdr * tree) { unsigned char *p = tree->p; return get_u32(&p); }
static inline unsigned int tree_hdr_get_size(struct tree_hdr * tree) { unsigned char *p = tree->p+4; return get_u32(&p); }
static inline unsigned int tree_hdr_get_low(struct tree_hdr * tree) { unsigned char *p = tree->p+8; return get_u32(&p); }

struct tree_hdr_h {
/*	unsigned int addr;
	unsigned int size;*/
	unsigned char p[8];
};
static inline unsigned int tree_hdr_h_get_addr(struct tree_hdr_h * tree) { unsigned char *p = tree->p; return get_u32(&p); }
static inline unsigned int tree_hdr_h_get_size(struct tree_hdr_h * tree) { unsigned char *p = tree->p+4; return get_u32(&p); }

struct tree_leaf_h {
/*	unsigned int lower;
	unsigned int higher;
	unsigned int match;
	unsigned int value;*/
	unsigned char p[16];
};
static inline unsigned int tree_leaf_h_get_lower(struct tree_leaf_h * tree) { unsigned char *p = tree->p; return get_u32(&p); }
static inline unsigned int tree_leaf_h_get_higher(struct tree_leaf_h * tree) { unsigned char *p = tree->p+4; return get_u32(&p); }
static inline unsigned int tree_leaf_h_get_match(struct tree_leaf_h * tree) { unsigned char *p = tree->p+8; return get_u32(&p); }
static inline unsigned int tree_leaf_h_get_value(struct tree_leaf_h * tree) { unsigned char *p = tree->p+12; return get_u32(&p); }


struct tree_hdr_v {
	/*unsigned int count;
	unsigned int next;
	unsigned int unknown;*/
	unsigned char p[12];
};
static inline unsigned int tree_hdr_v_get_count(struct tree_hdr_v * tree) { unsigned char *p = tree->p; return get_u32_unal(&p); }
static inline unsigned int tree_hdr_v_get_next(struct tree_hdr_v * tree) { unsigned char *p = tree->p+4; return get_u32_unal(&p); }
static inline unsigned int tree_hdr_v_get_unknown(struct tree_hdr_v * tree) { unsigned char *p = tree->p+8; return get_u32_unal(&p); }

struct tree_leaf_v {
	unsigned char key;
	/*int value;*/
	unsigned char p[4];
} __attribute__((packed));
static inline int tree_leaf_v_get_value(struct tree_leaf_v * tree) { unsigned char *p = tree->p; return get_u32_unal(&p); }

static int
tree_search_h(struct file *file, unsigned int search)
{
	unsigned char *p=file->begin,*end;
	int last,i=0,value,lower;
	struct tree_hdr_h *thdr;
	struct tree_leaf_h *tleaf;

	dbg(1,"enter\n");
	while (i++ < 1000) {
		thdr=(struct tree_hdr_h *)p;
		p+=sizeof(*thdr);
		end=p+tree_hdr_h_get_size(thdr);
		dbg(1,"@0x%x\n", p-file->begin);
		last=0;
		while (p < end) {
			tleaf=(struct tree_leaf_h *)p;
			p+=sizeof(*tleaf);
			dbg(1,"low:0x%x high:0x%x match:0x%x val:0x%x search:0x%x\n", tree_leaf_h_get_lower(tleaf), tree_leaf_h_get_higher(tleaf), tree_leaf_h_get_match(tleaf), tree_leaf_h_get_value(tleaf), search);
			value=tree_leaf_h_get_value(tleaf);
			if (value == search)
				return tree_leaf_h_get_match(tleaf);
			if (value > search) {
				dbg(1,"lower\n");
				lower=tree_leaf_h_get_lower(tleaf);
				if (lower)
					last=lower;
				break;
			}
			last=tree_leaf_h_get_higher(tleaf);
		}
		if (! last || last == -1)
			return 0;
		p=file->begin+last;
	}
	return 0;
}

static int
tree_search_v(struct file *file, int offset, int search)
{
	unsigned char *p=file->begin+offset;
	int i=0,count,next;
	struct tree_hdr_v *thdr;
	struct tree_leaf_v *tleaf;
	while (i++ < 1000) {
		thdr=(struct tree_hdr_v *)p;
		p+=sizeof(*thdr);
		count=tree_hdr_v_get_count(thdr);
		dbg(1,"offset=0x%x count=0x%x\n", p-file->begin, count);
		while (count--) {
			tleaf=(struct tree_leaf_v *)p;
			p+=sizeof(*tleaf);
			dbg(1,"0x%x 0x%x\n", tleaf->key, search);
			if (tleaf->key == search)
				return tree_leaf_v_get_value(tleaf);
		}
		next=tree_hdr_v_get_next(thdr);
		if (! next)
			break;
		p=file->begin+next;
	}
	return 0;
}

int
tree_search_hv(char *dirname, char *filename, unsigned int search_h, unsigned int search_v, int *result)
{
	struct file *f_idx_h, *f_idx_v;
	char buffer[4096];
	int h,v;

	dbg(1,"enter(%s, %s, 0x%x, 0x%x, %p)\n",dirname, filename, search_h, search_v, result);
	sprintf(buffer, "%s/%s.h1", dirname, filename);
	f_idx_h=file_create_caseinsensitive(buffer, 0);
	if ((!f_idx_h) || (!file_mmap(f_idx_h)))
		return 0;
	sprintf(buffer, "%s/%s.v1", dirname, filename);
	f_idx_v=file_create_caseinsensitive(buffer, 0);
	dbg(1,"%p %p\n", f_idx_h, f_idx_v);
	if ((!f_idx_v) || (!file_mmap(f_idx_v))) {
		file_destroy(f_idx_h);
		return 0;
	}
	if ((h=tree_search_h(f_idx_h, search_h))) {
		dbg(1,"h=0x%x\n", h);
		if ((v=tree_search_v(f_idx_v, h, search_v))) {
			dbg(1,"v=0x%x\n", v);
			*result=v;
			file_destroy(f_idx_v);
			file_destroy(f_idx_h);
			dbg(1,"return 1\n");
			return 1;
		}
	}
	file_destroy(f_idx_v);
	file_destroy(f_idx_h);
	dbg(1,"return 0\n");
	return 0;
}

static struct tree_search_node *
tree_search_enter(struct tree_search *ts, int offset)
{
	struct tree_search_node *tsn=&ts->nodes[++ts->curr_node];
	unsigned char *p;
	p=ts->f->begin+offset;
	tsn->hdr=(struct tree_hdr *)p;
	tsn->p=p+sizeof(struct tree_hdr);
	tsn->last=tsn->p;
	tsn->end=p+tree_hdr_get_size(tsn->hdr);
	tsn->low=tree_hdr_get_low(tsn->hdr);
	tsn->high=tree_hdr_get_low(tsn->hdr);
	dbg(1,"pos 0x%x addr 0x%x size 0x%x low 0x%x end 0x%x\n", p-ts->f->begin, tree_hdr_get_addr(tsn->hdr), tree_hdr_get_size(tsn->hdr), tree_hdr_get_low(tsn->hdr), tsn->end-ts->f->begin);
	return tsn;
}

int tree_search_next(struct tree_search *ts, unsigned char **p, int dir)
{
	struct tree_search_node *tsn=&ts->nodes[ts->curr_node];

	if (! *p) 
		*p=tsn->p;
	dbg(1,"next *p=%p dir=%d\n", *p, dir);
	dbg(1,"low1=0x%x high1=0x%x\n", tsn->low, tsn->high);
	if (dir <= 0) {
		dbg(1,"down 0x%x\n", tsn->low);
		if (tsn->low != 0xffffffff) {
			tsn=tree_search_enter(ts, tsn->low);
			*p=tsn->p;
			tsn->high=get_u32(p);
			ts->last_node=ts->curr_node;
			dbg(1,"saving last2 %d 0x%x\n", ts->curr_node, tsn->last-ts->f->begin);
			dbg(1,"high2=0x%x\n", tsn->high);
			return 0;
		}
		return -1;
	}
	tsn->low=tsn->high;
	tsn->last=*p;
	tsn->high=get_u32_unal(p);
	dbg(1,"saving last3 %d %p\n", ts->curr_node, tsn->last);
	if (*p < tsn->end)
		return (tsn->low == 0xffffffff ? 1 : 0);
	dbg(1,"end reached high=0x%x\n",tsn->high);
	if (tsn->low != 0xffffffff) {
		dbg(1,"low 0x%x\n", tsn->low);
		tsn=tree_search_enter(ts, tsn->low);
		*p=tsn->p;
		tsn->high=get_u32_unal(p);
		ts->last_node=ts->curr_node;
		dbg(1,"saving last4 %d 0x%x\n", ts->curr_node, tsn->last-ts->f->begin);
		dbg(1,"high4=0x%x\n", tsn->high);
		return 0;
	}
	return -1;
}

int tree_search_next_lin(struct tree_search *ts, unsigned char **p)
{
	struct tree_search_node *tsn=&ts->nodes[ts->curr_node];
	int high;
	
	dbg(1,"pos=%d 0x%x\n", ts->curr_node, *p-ts->f->begin);
	if (*p)
		ts->nodes[ts->last_node].last=*p;
	*p=tsn->last;
	for (;;) {
		high=get_u32_unal(p);
		if (*p < tsn->end) {
			ts->last_node=ts->curr_node;
			while (high != 0xffffffff) {
				tsn=tree_search_enter(ts, high);
				dbg(1,"reload %d\n",ts->curr_node);
				high=tsn->low;
			}
			return 1;
		}
		dbg(1,"eon %d 0x%x 0x%x\n", ts->curr_node, *p-ts->f->begin, tsn->end-ts->f->begin);
		if (! ts->curr_node)
			break;
		ts->curr_node--;
		tsn=&ts->nodes[ts->curr_node];
		*p=tsn->last;
	}

	return 0;
}

void
tree_search_init(char *dirname, char *filename, struct tree_search *ts, int offset)
{
	char buffer[4096];
	sprintf(buffer, "%s/%s", dirname, filename);
	ts->f=file_create_caseinsensitive(buffer, 0);
	ts->curr_node=-1;
	if (ts->f) {
		file_mmap(ts->f);
		tree_search_enter(ts, offset);
	}
}

void
tree_search_free(struct tree_search *ts)
{
	if (ts->f)
		file_destroy(ts->f);
}