mod_tile/src/metatile.cpp

/*
 * Copyright (c) 2007 - 2020 by mod_tile contributors (see AUTHORS file)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * 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, see http://www.gnu.org/licenses/.
 */

#include "config.h"

#include <string.h>
#include <limits.h>
#include <stdlib.h>

#include "render_config.h"
#include "metatile.h"
#include "store.h"
#include "cache_expire.h"
#include "request_queue.h"
#include "g_logger.h"


metaTile::metaTile(const std::string &xmlconfig, const std::string &options, int x, int y, int z):
	x_(x), y_(y), z_(z), xmlconfig_(xmlconfig), options_(options)
{
	clear();
}

void metaTile::clear()
{
	for (int x = 0; x < METATILE; x++)
		for (int y = 0; y < METATILE; y++) {
			tile[x][y] = "";
		}
}

void metaTile::set(int x, int y, const std::string &data)
{
	tile[x][y] = data;
}

const std::string metaTile::get(int x, int y)
{
	return tile[x][y];
}

// Returns the offset within the meta-tile index table
int metaTile::xyz_to_meta_offset(int x, int y, int z)
{
	unsigned char mask = METATILE - 1;
	return (x & mask) * METATILE + (y & mask);
}

void metaTile::save(struct storage_backend * store)
{
	int ox, oy, limit;
	ssize_t offset;
	struct meta_layout m;
	struct entry offsets[METATILE * METATILE];
	char * metatilebuffer;
	char *tmp;

	memset(&m, 0, sizeof(m));
	memset(&offsets, 0, sizeof(offsets));

	// Create and write header
	m.count = METATILE * METATILE;
	memcpy(m.magic, META_MAGIC, strlen(META_MAGIC));
	m.x = x_;
	m.y = y_;
	m.z = z_;

	offset = header_size;
	limit = (1 << z_);
	limit = MIN(limit, METATILE);
	limit = METATILE;

	// Generate offset table
	for (ox = 0; ox < limit; ox++) {
		for (oy = 0; oy < limit; oy++) {
			int mt = xyz_to_meta_offset(x_ + ox, y_ + oy, z_);
			offsets[mt].offset = offset;
			offsets[mt].size   = tile[ox][oy].size();
			offset += offsets[mt].size;
		}
	}

	metatilebuffer = (char *) malloc(offset);

	if (metatilebuffer == 0) {
		g_logger(G_LOG_LEVEL_WARNING, "Failed to write metatile. Out of memory");
		return;
	}

	memset(metatilebuffer, 0, offset);
	memcpy(metatilebuffer, &m, sizeof(m));
	memcpy(metatilebuffer + sizeof(m), &offsets, sizeof(offsets));

	// Write tiles
	for (ox = 0; ox < limit; ox++) {
		for (oy = 0; oy < limit; oy++) {
			memcpy(metatilebuffer + offsets[xyz_to_meta_offset(x_ + ox, y_ + oy, z_)].offset, (const void *)tile[ox][oy].data(), tile[ox][oy].size());
		}
	}

	if (store->metatile_write(store, xmlconfig_.c_str(), options_.c_str(), x_, y_, z_, metatilebuffer, offset) != offset) {
		tmp = (char *)malloc(sizeof(char) * PATH_MAX);
		g_logger(G_LOG_LEVEL_WARNING, "Failed to write metatile to %s", store->tile_storage_id(store, xmlconfig_.c_str(), options_.c_str(), x_, y_, z_, tmp));
		free(tmp);
	}

	free(metatilebuffer);
}


void metaTile::expire_tiles(int sock, char * host, char * uri)
{
	if (sock < 0) {
		return;
	}

	g_logger(G_LOG_LEVEL_INFO, "Purging metatile via HTCP cache expiry");
	int ox, oy;
	int limit = (1 << z_);
	limit = MIN(limit, METATILE);

	// Generate offset table
	for (ox = 0; ox < limit; ox++) {
		for (oy = 0; oy < limit; oy++) {
			cache_expire(sock, host, uri, (x_ + ox), (y_ + oy), z_);
		}
	}
}